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Staphylococcus in a dog: symptoms and treatment of infection [wet Krystyna Skiersinis

Staphylococcus in a dog

Many pet owners are dismayed by the information that their dog was diagnosed with staphylococcus, associating the bacterium with human golden staphylococcus. Indeed, these microbes in humans can cause serious health problems and, in some situations, even life-threatening conditions.

But is there anything to be afraid of when it comes to dogs??

Is "staphylococcus" in the results of the microbiological test really a cause for panic?

Or is it simply an innocent bacterium that is part of the cutaneous and mucosal microflora??

This study aims to familiarize the reader with the problem of bacteria with a rather repulsive name "staphylococci ".

I will answer the questions that pet keepers often ask in the veterinary office, and which - in most cases - are perfectly justified.

I will try to "tame " these microorganisms a little, and present the complicated differences between individual species of staphylococci in a slightly more accessible form.

I will describe which species of staphylococci pose a real threat to animal and human health, how they can be infected, who is at increased risk and how to protect themselves against infection caused by these microorganisms.

I hope this article will dispel many doubts related to staphylococcal infections in dogs.

  • Staphylococcus - what is it?
  • Classification of staphylococci
    • Staphylococcus Intermedius group - SIG (Staphylococcus intermedius group)
  • Staphylococcus aureus - golden staphylococcus
    • What is mrsa and staphylococcus aureus?
    • What diseases does golden staphylococcus?
    • How can I get infected with staphylococcus aureus?
    • Is mrsa dangerous to me?
    • Who is at risk?
    • How is mrsa colonization or infection diagnosed??
    • How is mrsa treated in humans?
    • How does a dog become infected with staphylococcus aureus?
    • Are there any factors that predispose dogs to Staphylococcus aureus infection??
    • Should I be worried about my dog?
    • What if the dog tests positive for mrs?
    • What can I do to protect myself and my family?
  • Staphylococcus pseudointermedius
    • What is mrsp and staphylococcus pseudintermedius?
    • What diseases does staphylococcus pseudointermedius cause?
    • How common is mrsp in dogs?
    • Can people get MRSP?
    • How mrsp infestation occurs in humans and animals?
    • What is the risk of colonization or infection by mrsp in humans?
    • Are there any predisposing factors to colonization or infection by mrsp?
    • What are the symptoms of staphylococcal infection caused by staphylococcus pseudintermedius in humans?
    • What happens when a dog becomes infected with mrsp?
    • What are the differences between mrsp and mrsa?
    • How is mrsp?
    • How are staphylococcus pseudointermedius and mrsp infections treated??
    • What should I do if my pet is colonized with mrsp?
    • How long will my pet be colonized by mrsp?
    • What should I do if my pet has mrsp infection?
    • How can I prevent my dog ​​from infecting my dog ​​with mrsp?
  • Staphylococcus intermedius and the controversy related to its classification
    • What is mrsi and staphylococcus intermedius?
  • Other species of staphylococci isolated from humans and animals
    • Staphylococcus schleiferi
  • Antibiotic resistance among staphylococci
    • What is antibiotic resistance?
    • Where did antibiotic resistance come from?
  • Staphylococcal infections in dogs
    • Pathogenesis of staphylococcal infections
  • How microbes inhabit the body?
  • What diseases can cause staphylococcal infections in dogs?
  • How are staphylococcal infections diagnosed?
  • Medications for staphylococcus in dogs
  • A threat to public health

Staphylococcus - what is it?

What is staphylococcus?

Staphylococci, otherwise staphylococci (pour. Staphylococcus) is a genus of bacteria that was discovered in 1882 by Sir Alexander Ogston. He observed gram-positive, spherical, immobile, small-grain-shaped bacteria (the so-called. kernels), which were arranged in irregular clusters, resembling clusters. He named the observed microorganisms "staphylococci " - staphylococci (gr. staphyle - grapes, coconut - grain).

Two years later, another researcher - Friedrich Julius Rosenbach, bred, isolated and defined two species of staphylococci:

  1. Staphylococcus aureus (Staphylococcus aureus).
  2. Staphylococcus albus (white staphylococcus), now known as Staphylococcus epidermidis.

In 1976, Václav Hájek distinguished a new species of coagulase-positive staphylococci - Staphylococcus intermedius (indirect staphylococcus).

Its name referred to certain features that shared it with the other two species - some biochemical properties were typical of S. aureus, and on the other hand, the white color of the colony resembled rather NS. epidermidis.

For several dozen years Staphylococcal strains which were isolated from dogs and which caused, among others, pyoderma and inflammation of the external ear canal were classified as S. intermedius.

However, in 2005, thanks to the significant progress made in the field of molecular biology, the classification of staphylococci was changed and it was found that the diseases previously attributed to Staphylococcus intermedius are predominantly caused by the species Staphylococcus pseudointermedius (Gr. pseudes - false).

Staphylococci are conditionally aerobic (they grow in aerobic and anaerobic conditions), gram-positive cocci, whose main habitat is the skin and mucous membranes of mammals and birds.

More than 50 species are distinguished in the group of staphylococci.

All staphylococcal species that are isolated from animals are potentially pathogenic.

Some of them are characterized by a wide range of virulence, the possibility of attacking many species of animals, and the specificity of the attacked site.

Of all staphylococcal species, a small number are commonly isolated from cases of infections in dogs and cats.

Interestingly, bacteria that are adapted to a specific host (e.g. dog) may, for a short time, colonize the host organism belonging to another species (e.g. human), provided that contact between them is frequent and if an infection occurs.

Staphylococci are also present in the external environment where animals live - they are easily isolated from soil, objects, air and water, as well as from various animal products.

Despite the fact that they are non-spore-forming bacteria, staphylococci survive well in the external environment, being one of the most resistant to drying and disinfection of microorganisms.

Staphylococci are characterized by low virulence and can colonize intact epithelium of healthy animals without causing any symptoms of disease.

This means that animals can be short-term or permanent subclinical carriers of staphylococci.

However, since these bacteria are opportunistic microorganisms, they can attack the epithelium when it is damaged.

The skin barrier may be impaired as a result of:

  • epithelial injuries, e.g.:
    • incisions,
    • wounds,
    • cuts,
  • other skin infections, e.g.:
    • demodicosis,
    • dermatophytosis,
  • certain general or local disorders, e.g.:
    • seborrhea,
    • thyroid dysfunction,
    • immunosuppression.

This is why staphylococcal disease is believed to be the result of an imbalance in the host organism.

A characteristic feature of diseases caused by staphylococci is the formation of abscesses, since the main line of defense against these bacteria is leukocytes.

Classification of staphylococci

Staphylococci - due to their ability to produce coagulase - have been generally divided into:

  • coagulase-positive staphylococci (CPS),
  • coagulase-negative staphylococci (CNS).

At least seven species of coagulase-positive staphylococci are isolated from animals, such as:

  • Staphylococcus pseudointermedius,
  • NS. aureus,
  • NS. schleiferi subsp. coagulans,
  • NS. delphini,
  • NS. intermedius,
  • NS. hyicus,
  • NS. lutrae.

Coagulase-negative strains:

  • Coagulase-negative Staphylococcus scirui strains are widespread in nature and have been isolated from the mucous membranes of the nostrils and mouth and the hairy skin of dogs.
  • Staphylococcus epidermidis (epidermis - outer shell, skin) - coagulase-negative commensal, present on the skin and mucous membranes, was isolated in dogs with discospondylosis (this disease is most often caused by S. intermedius)
  • Coagulase negative Staphylococcus schleiferi subsp. schleiferi and coagulase - positive S. schleiferi subsp. coagulans was isolated from the skin of dogs with recurrent pyoderma.

Coagulase-negative staphylococci were considered harmless, moderately or completely non-pathogenic bacteria for many years.

Extremely often, these microorganisms, isolated from biological material obtained from patients, were treated as contaminants without much clinical significance.

They were treated as saprophytic microflora, not posing a threat and causing no disease.

However, it is currently known that coagulase-negative staphylococci can also cause serious illnesses in humans and animals.

Staphylococcus Intermedius group - SIG (Staphylococcus intermedius group)

As already mentioned, detailed studies of staphylococci found in dogs and other animals led to the description of a new species of Staphylococcus pseudointermedius in 2005.

Bacteria previously isolated and recognized as S. intermedius in fact belong to the species S. pseudointermedius.

With the discovery of this species, the SIG group was created, in which three closely related species of staphylococci were distinguished:

  • NS. pseudointermedius,
  • NS. delphini,
  • NS. intermedius.

Their phenotypic identification is particularly difficult as their phenotypic characteristics often overlap.

This causes great diagnostic difficulties, and the identification of a specific species is possible only thanks to the use of molecular biology techniques.

In 2007, the results of research conducted with the use of molecular biology techniques on strains previously recognized as S. intermedius.

It turned out that all isolates from dogs, cats and humans belonged to the species S. pseudointermedius.

Most of the strains isolated from horses and breeding pigeons belonged to S. delphini.

In turn, the strains derived from city pigeons are mostly S. intermedius.

We now know that it is S. pseudointermedius is the predominant species of staphylococcus in dogs. Occasionally it occurs in other animal species and in humans.

NS. delphini was originally isolated from purulent lesions found on the skin of dolphins. It also occurs in mink, breeding pigeons and horses.

NS. intermedius is currently the least known species from the SIG group. It occurs in city pigeons.

This is - to put it very simply - the classification of staphylococci.

However, we are primarily interested in two species:

  • Staphylococcus pseudointermedius, whose favorite host is the dog,
  • Staphylococcus aureus - a bacterium found primarily in humans.

Such differentiation between canine and human strains is not entirely precise, because - as it will turn out in a moment - these staphylococci can live and cause diseases in many species of animals and in humans, changing their hosts and adapting to the prevailing conditions.

Staphylococcus aureus - golden staphylococcus

Diseases caused by staphylococci

What is mrsa and staphylococcus aureus?

Staphylococcus aureus - golden staphylococcus - is a bacterium that is a normal resident of the skin and nasal passages of humans and some animals.

The natural host of S. aureus are people - it inhabits the nasal passages in about 30-40% of healthy adults (less often other places), without causing skin diseases.

It is estimated that at least 10% of healthy people are regular carriers of Staphylococcus aureus, and 70-90% are so-called. transitional vectors.

MRSA or methicillin-resistant Staphylococcus aureus is an emerging bacterial pathogen that is resistant to many commonly used antibiotics.

It is estimated that approximately 1.5% of the population may be carriers of methicillin-resistant staphylococcus aureus.

Small animal veterinarians are three times more likely to be at risk of nasal carriage of MRSA strains, with a 4.4% carrier rate.

There are also other species of Staphylococcus that are also resistant to methicillin, but the likelihood of infection with these bacteria is very low.

Asymptomatic carrier status and the increasing resistance to antibiotics among the strains of Staphylococcus aureus, which are more and more often observed, are conducive to the spread of microorganisms not only among humans, but also animals.

Animals may be infected or may be carriers of methicillin-sensitive MSSA (methicillin-sensitive strains). aureus) and MRSA.

There is a possibility of golden staphylococcus a transfer between animals and humans, therefore dogs and cats can be a potential reservoir of this pathogen for humans.

What diseases does golden staphylococcus?

Under normal circumstances, bacteria do not cause serious disease or health problems for humans and animals.

However, under certain circumstances, when the surface of the skin is damaged (cuts, scrapes, bites, surgical wounds) or the body's ability to fight infectious diseases is impaired or completely absent (immunosuppression or immunodeficiency), Staphylococcus aureus can infect the wound and / or cause disease.

In this case, antibiotics are essential to treat the infection.

Golden staphylococcus is considered the main pathogenic species in humans and may be responsible for many serious infections.

Human infections can be divided into:

  • skin diseases,
  • respiratory system diseases,
  • diseases of the urinary system,
  • gastrointestinal diseases,
  • sepsis and ropowice,
  • nipple inflammation,
  • purulent arthritis,
  • inflammation of the bone marrow and bones,
  • meningitis,
  • Ritter's disease,
  • toxic shock syndrome.

How can I get infected with staphylococcus aureus?

These bacteria can be found all around us.

Remember that Staphylococcus aureus and MRSA are zoonotic pathogens.

This means you can transfer the bacteria to your dog and your dog to you.

This staphylococcus is also present in some environments and you or your pet can acquire an infection through contact with such infected objects.

Exposure to staphylococci can occur in several different ways. They include:

  • contact with an infected person,
  • contact with a polluted environment,
  • recent hospitalization or invasive medical management (e.g. surgery, severe disease, catheterization, or even a cannula),
  • contact with pets or other animals that carry bacteria.

It should be remembered that just contact with bacteria (regardless of their source) does not mean that an infection will occur.

In fact, the vast majority of people exposed to Staphylococcus aureus will not develop the disease.

For bacteria to be able to cause infection, there must be another underlying disease that weakens the immune system, or a wound that is the gateway for microbes to enter.

Is mrsa dangerous to me?

Under normal circumstances, when a person is healthy, MRSA does not cause significant disease.

However, if the skin is damaged or the immune system is weakened (for various reasons, e.g. current cancer and concomitant chemotherapy, recent surgery, invasive medical procedure, steroid therapy, or even another disease that weakens the body), MRSA can cause serious or life-threatening diseases.

In humans, MRSA infections have been and still are the cause of very serious health complications.

Due to the fact that out-of-hospital infections with MRSA are becoming more frequent, and there is also the possibility of the strain being transferred to pets, this infection can be a serious problem, making it difficult to combat not only staphylococcal infection, but also the treatment of the underlying disease.

For infections with strains that are resistant to multiple antibiotics, some antibacterial agents such as vancomycin, teicoplanin, and oxozalidin derivatives such as linezolid are the only agents that are effective against methicillin-resistant staphylococcus aureus.

Who is at risk?

The following are at risk of infection with MRSA strains, known as hospital aquired MRSA (HA-MRSA) strains:

  • Primarily health care workers who are at increased risk of carriage or infections with Staphylococcus aureus.
  • An increased risk of colonization with these strains also occurs in people who have been hospitalized or have had contact with such people, as well as in people who have had contact with the hospital environment in some other way (e.g. parents, staying in the hospital with their child, volunteers, etc.).
  • The percentage of people with isolates of hospital strains is 7.6-11.1%.
  • More frequent colonization with these strains also occurs in veterinarians and auxiliary staff.

People who are not related to the hospital environment are usually infected or are carriers of methicillin-sensitive strains (methicillin-sensitive S. aureus - MSSA).

They may also have methicillin-resistant strains, known as community-aquired MRSA (CA-MRSA).

About 0.8-3.5% of healthy people are carriers of CA-MRSA strains.

How is mrsa colonization or infection diagnosed??

In animals, as in humans, the material for testing for the presence of S. aureus is most often collected from the atrium of the nasal cavity, but staphylococcus may also occur elsewhere on the mucous membranes or skin.

Such material is sent to a laboratory, where a bacteriological test is performed (lasting several days) and the antibiotic sensitivity of the bacteria is determined.

How is mrsa treated in humans?

Vancomycin is used to treat MRSA infections in humans.

It is an extremely important drug, which in many situations is the so-called. the drug of last resort.

Unfortunately, there are reports that staphylococci, even in the face of such heavy artillery, do not give up and become resistant to its effects.

Therefore, there are strains resistant to vancomycin - VRSA (vankomycin-resistant Staphylococcus aureus) and strains with reduced susceptibility to vancomycin - VISA (vankomycin-intermediate S. aureus).

Episodes of resistance to this drug have been reported in human medicine, the first of which was reported in 1997.

A strain of methicillin-resistant staphylococcus with reduced susceptibility to vancomycin was then isolated from the infant.

Although only isolated cases of infections with VRSA strains have been reported, they pose a growing threat, as there may be a situation where there is no longer any drug effective in the fight against staphylococci.

How does a dog become infected with staphylococcus aureus?

Although staphylococcus aureus is a human pathogen, an increasing number of cases of infection with this staphylococcus are observed in animals, and therefore they may be an important factor in the spread of microorganisms.

Animals become infected with this staphylococcus in the same way as humans - through contact with an infected person or animal, a contaminated environment, or recent invasive medical procedures (especially those where asepsis is not followed).

Staphylococcus aureus accounts for less than 10% of isolates from healthy dogs and cats.

It is adapted primarily to humans, but may occasionally colonize animal organisms.

The transmission of germs occurs primarily through direct human-animal contact, but an indirect route may also be important - through a polluted environment.

Staphylococcus can be found on all surfaces and equipment that are used by household members.

Therefore, not only close contact, but also staying in the same room for a long time, can increase the risk of infection.

Methicillin-resistant Staphylococcus aureus (MRSA, often called "mersa ") can be transmitted from humans to pets - such infections are called reverse anthropozoonoses.

An example of such a reverse zoonotic infection is MRSA in a dog, which develops as a postoperative infection (staphylococci have entered. at the hands of the surgeon or operating equipment).

Reverse anthropozoonosis can also be a skin or urinary tract infection that occurs in a dog as a result of contact with its owner who has recently been hospitalized or works in the healthcare sector and has frequent contact with bacteria.

The colonized or infected pets can then act as a reservoir of bacteria, thus facilitating their transfer to humans, colonization, or infection, especially if they have an impaired immune system.

In various parts of the world, MRSA strains have been isolated from dogs from wound infections, from surgical (especially orthopedic) wounds, and from animals with recurrent pyoderma.

Particularly dangerous strains of Staphylococcus aureus are isolated in hospitals, where they can even cause life-threatening conditions (e.g. sepsis syndrome).

Although methicillin-resistant strains of S. aureus are mainly a source of nosocomial infections, but their ability to adapt to the environment increases, which also results in out-of-hospital infections.

Nosocomial MRSA infections are associated with microbes that are resistant to all commonly used antibiotics.

MRSA infections in dogs are usually caused by outpatient strains of staphylococci, which, unlike inpatient strains, are usually resistant only to β-lactam antibiotics, but respond well to other oral antibiotics.

Are there any factors that predispose dogs to Staphylococcus aureus infection??

Predisposing factors for colonization and / or golden staphylococcus in dogs are:

  • previous treatment with antibiotics, often multiple;
  • longer stay in the clinic;
  • surgery,
  • steroid therapy,
  • chemotherapy,
  • weakening of the immune system.

Animals whose owners are in constant contact with hospitals or animal clinics are more likely to be carriers or infections caused by staphylococcus aureus.

Should I be worried about my dog?

Overall, Staphylococcus aureus is a rare cause of infection in animals.

Dogs rarely carry this staphylococcus as a component of the normal bacterial cutaneous and mucosal flora.

These staphylococci prefer humans, although there are occasional cases of infections caused by S. aureus in dogs.

In animals, as in humans, Staphylococcus aureus may constitute a commensal flora, but in healthy animals it is much less common than in humans.

It can cause all kinds of infections, from mild skin infections to severe bacteraemia.

However, there is a strain of Staphylococcus aureus that is resistant to many antibiotics (e.g. penicillin, amoxicillin) commonly used to treat skin infections and related diseases, increasing the likelihood of treatment failure.

Animals with MRSA should be treated in a veterinary hospital and isolated.

What if the dog tests positive for mrs?

Talk to your veterinarian who can help you determine the best treatment for your dog based on the health risks to you, your family and pets in your household.

There is usually no need to get rid of the pet - remember that healthy people or animals very rarely develop the disease under normal circumstances.

Additionally, MRSA is highly adapted to humans but not to other animal species, therefore if your pet is MRSA positive it is possible that your dog's primary source of infection is either you or someone in your home.

If your dog is colonized with MRSA:

  • wash your hands after each contact with your dog, as well as after touching his toys, lair, water bowls or food;
  • avoid contact with the dog's nose, mouth and anus area;
  • prohibit licking the face or other parts of the body, especially those where the skin is broken;
  • avoid contact of the dog with people (especially sick, immunosuppressed, after treatment, etc.);
  • limit contacts with other dogs;
  • immediately after the dog defecates, remove the faeces and throw it into specially designed baskets;
  • do not let the dog sleep from the bed;
  • blankets, bedding and fabric toys should be washed regularly.

In the event of an infection caused by MRSA, your veterinarian will prescribe the appropriate treatment for your dog.

If you have any doubts or are concerned about your own health or that of one of your family members, be sure to consult a medical doctor and veterinarian.

Indeed, there are times when the presence of a dog colonized or infected with MRSA is highly dangerous.

This could be, for example, the presence of an adult or a child at home with cancer, during or after chemotherapy, immunosuppressed, transplant, etc.

I know from experience that in such cases, even a small bacterial infection can be extremely dangerous and have serious consequences.

It is known that then it is necessary to isolate such people not only from sick animals, but also to minimize contact with sick people and their environment.

What can I do to protect myself and my family?

When it comes to contact with animals, follow your veterinarian's instructions in all cases and take basic precautions to minimize the transmission of these bacteria.

  • After playing or other contact with the dog, as well as touching or washing its water or food bowls, toys, lairs, etc. wash your hands thoroughly with warm soapy water.
  • If you have any cuts or scratches, keep them clean and cover them with a dressing, especially when handling your dog.
  • Do not share food with your dog and avoid contact with your personal belongings such as. towels.
  • Do not allow your face or wounds to be licked.
  • Avoid direct dog contact with cuts or scrapes and use gloves to clean them.
  • Do not sleep with your dog if you are immunocompromised or at risk.
  • When handling sick animals, use additional personal hygiene measures such as hand disinfectants, masks, disposable gloves, etc.

Staphylococcus pseudointermedius

What is mrsp and staphylococcus pseudintermedius?

Staphylococcus pseudointermedius is a bacterium commonly found on the skin, mouth, nose, or digestive tract in 90% or more of healthy dogs (and less in healthy cats).

It is a component of the normal, physiological bacterial flora of the skin.

Typically, this staphylococcus does not cause any problems, but is an opportunistic pathogen, meaning that if an animal experiences any kind of injury (e.g. skin breaks, bites or injuries in other circumstances) or becomes sick for some other reason, this bacterium can take advantage of the body's weakened immune system and cause infection and illness.

This may also be the case when the animal is treated with immunosuppressive drugs.

MRSP or methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a form of staphylococcus that is highly resistant to many antibiotics commonly used to treat bacterial infections in dogs and cats.

Staphylococci other than MRSP are methicillin-sensitive.

What diseases does staphylococcus pseudointermedius cause?

Staphylococcus pseudointermedius can infect any tissue, but skin and soft tissue infections are most common in dogs, especially when the skin is damaged (e.g. as a result of allergies, intense scratching, humid environment, wounds, surgery, etc.).

Infections other parts of the body and organs are less common but can be very serious.

Staphylococcus pseudointermedius is the leading bacterium in cases of pyoderma, otitis and wound infections.

It is by far the most common cause of staphylococcal infections in pets and is much more common than Staphylococcus aureus.

Overall, most S. pseudointermedius is still sensitive to the most commonly used beta-lactam antibiotics.

How common is mrsp in dogs?

Healthy animals may be carriers of MRSP (they do not show clinical signs of infection then).

One study found MRSP in 4.5% of healthy dogs, and more recent studies show that the percentage is even higher.

Infections with methicillin-resistant Staphylococcus pseudintermedius appear to increase significantly in animals, however, especially in dogs.

Veterinary dermatology specialists report a very large increase in MRSP skin infections (usually as pyoderma).

Also, post-operative infections are becoming more common and can be very difficult to treat.

Can people get MRSP?

Yes, but it seems quite rare. There are only a few reported human MRSP infections in the world.

Infections in humans methicillin-sensitive S. pseudointermedius are also rare, although dog owners are exposed to these bacteria on a regular (if not daily) basis.

This bacterium is clearly not well suited to causing disease in humans.

While the risk of infection is not zero, it is not a serious health problem.

The isolation of S. pseudointermedius from humans occur really sporadically, but an interesting fact is that these staphylococci are more often found in people who have constant contact with dogs.

It is estimated that human colonization by this species of staphylococcus is about 1% (or less). On the other hand, asymptomatic carriage is more common in dog keepers and reaches 3.7% of the respondents.

Interestingly, staphylococcal strains with identical genotypic characteristics were isolated in the owners and their dogs.

The occurrence of MRSP was therefore found in healthy people, and more often it concerned people who were in constant contact with dogs.

Veterinarians are particularly concerned with this problem, although dog owners may have even higher rates of MRSP.

In many cases, however, it is a transient type of carrier, as evidenced by studies conducted on dog handlers several months after the isolation of staphylococci.

Often, the presence of these bacterial strains is not found in re-examination. This may not be the case for veterinarians who are continuously exposed to patient strains of MRSP.

Unfortunately, there is a high probability of misdiagnosing S. pseudointermedius as S. aureus or coagulase-negative staphylococci (CNS), hence the concern that the results of studies on the occurrence of S. pseudointermedius in humans is underestimated.

How mrsp infestation occurs in humans and animals?

MRSP transmission can be omni-directional - it can spread between dogs and humans, but also between humans and dogs.

Although carriage in humans is usually temporary, infection may occur under favorable circumstances.

As is the case with colonization, also here MRSP infections more often affect people who have frequent contact with dogs.

The main source of methicillin-resistant Staphylococcus pseudointermedius is usually healthy, colonized animals with no signs of contamination.

MRSP is likely to be transmitted between animals through direct contact.

Indirect transmission (i.e. where a person or animal does not touch an object or surface that has been contaminated with MRSP by another animal) is theoretically possible, but possibly rare.

Humans most likely become infected through direct contact with an infected or colonized domestic animal.

People who wash their hands regularly after touching their pets have been shown to be less likely to carry S. pseudointermedius than people who do not wash their hands regularly.

Transmission of MRSP from humans to pets can also occur, although the risk is likely very low as MRSP is very rare in humans.

Methicillin-resistant Staphylococcus pseudointermedius strains may survive in the environment for a limited time, but are susceptible to the most common disinfectants (surface or equipment must be cleaned beforehand).

What is the risk of human colonization or infection by mrsp?

The risk to the general human population of zoonotic infection of MRSP from clinically healthy dogs is low.

The risk of infection (on a scale of 1-10) is 1-2.

People with a compromised immune system (transplant, cancer or HIV patients) are more prone to many types of infections, including those transmitted by pets.

Although most physicians do not recommend that their patients get rid of pets, precautions should be taken to reduce the frequency of contact that may cause transmission of pathogens (e.g. avoiding contact with open wounds, feces).

The ability of infectious agents to disrupt the household (e.g. quick and thorough disinfection of potentially contaminated surfaces).

Immunocompromised people should avoid contact with animals colonized or infected with MRSP.

Babies and young children (under 5 years of age) are more likely than adults to come into contact with pathogens due to increased contact with animals (playing, licking the face, putting toys or sweets in the mouth, licked by a dog, touching their nose more often and dog's mouth, etc.) and less frequent hand washing after contact with the animal.

Such close contact with an animal in children whose immune system is not fully developed yet may increase the risk of disease transmission.

Young children should be supervised when playing with animals, and an adult should ensure that they wash their hands well after handling (especially before eating). Older children must be taught the same.

For these groups of people, the risk of zoonotic infection from MRSP is higher.

Are there any predisposing factors to colonization or infection by mrsp?

The risk factors for MRSP in pets are unknown.

Treatment with antibiotics is a potential risk factor.

What are the symptoms of staphylococcal infection caused by staphylococcus pseudintermedius in humans?

People and animals who develop MRSP but without any clinical signs are considered colonized by staphylococcus.

When Staphylococcus pseudointermedius infection occurs, symptoms of inflammation appear, such as:

  • increasing the temperature of the affected tissue,
  • ache,
  • edema,
  • exudate (most often purulent),
  • fever.

Previously, canine staphylococcal infections have been associated with the infection of bite wounds.

Recently, more and more often (fortunately, sporadically) are cases of infections that have nothing to do with bites, and mainly concern postoperative wounds, sinuses, heart infections after pacemaker implantation in the elderly, varicose and varicose ulcers and brain abscesses.

These staphylococci also lead to bacteremia as a result of the insertion of intravenous catheters.

There are also reports of MRSP infections, such as e.g.:

  • hospital pneumonia,
  • recurrent sinusitis,
  • infections in bone marrow recipients.

Most often, patients are in constant contact with dogs.

What happens when a dog becomes infected with mrsp?

What happens when a dog becomes infected with mrsp?

In dogs, MRSP most commonly causes skin and ear infections.

They can also develop wound infections, surgical site infections, and other types of infections.

Rarely, MRSP can cause severe disease such as necrotizing fasciitis.

Although MRSP infections can be difficult to treat, the available evidence suggests that the treatment effect should be similar to that of a methicillin-susceptible strain, provided that MRSP is diagnosed promptly and appropriate treatment initiated immediately.

If MRSP is not diagnosed in time and / or antibiotics are ineffective, it is possible that a more serious disease may develop.

What are the differences between mrsp and mrsa?

Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant form of S. aureus.

Although S. aureus and S. pseudointermedius are related, MRSA and MRSP are very different.

In humans, MRSA can be a serious health problem, often requiring hospitalization, while in animals it is only a marginal problem.

In turn, MRSP (methicillin-resistant Staphylococcus pseudintermedius) in dogs is quite a serious health problem, but MRSP infections are much less common in humans.

MRSA can infect both humans and animals and can be transferred relatively easily between humans and animals in both directions.

It appears that MRSP can also be transmitted from animals to humans, but this is probably a rare phenomenon.

Therefore, the risk of zoonoses caused by MRSP is low.

How is mrsp?

MRSP is diagnosed on a bacteriological basis that lasts for several days.

From the picture of the infection alone, it is impossible to tell which bacteria are involved.

Infections with methicillin-resistant staphylococcal strains do not differ significantly from those with susceptible strains or other staphylococcal bacteria.

The only way to distinguish them is through a culture test and an antibiotic susceptibility test.

When diagnosing a carrier, it is important to collect material from places that staphylococci are particularly fond of, i.e. the skin around the perineum and the oral mucosa.

How are staphylococcus pseudointermedius and mrsp infections treated??

Infection with methicillin susceptible strains of Staphylococcus pseudointermedius (MSSP):

  • Antibacterial agents used in veterinary dermatology include: amoxicillin with clavulanic acid, cephalosporins, fluoroquinolones and lincosamides.
    Empirical therapy may be effective in infections caused by methicillin-susceptible staphylococci, but in multidrug-resistant strains, culture testing and determination of antibiotic susceptibility are necessary, especially in resistant cases.
  • Most staphylococcal infections in dogs can be successfully treated with amoxicillin / clavulanic acid or cephalotin.
  • Certain canine infections, e.g. pyoderma and some forms of otitis externa often require repeated and / or long-term antimicrobial treatment.
    Difficult cases are often treated with fluoroquinolones and may require continuous treatment for up to 7 months.

Infection with methicillin-resistant Staphylococcus pseudintermedius:

  • Antimicrobial treatment must be based on reliable results of bacterial susceptibility testing. There are a limited number of medications that can be used.
    One of the effective antibacterial drugs that is active against gram-positive bacteria (including methicillin-resistant staphylococci) is mupirocin.
    In veterinary medicine it is sometimes used topically as a medicine to treat purulent dermatitis in dogs.
  • All MRSP strains are resistant to beta-lactam antibiotics (e.g. penicillins, cephalosporins), but due to the fact that different strains may be resistant to other groups of antibiotics at the same time, it is necessary to test the antibiotic sensitivity of bacteria in order to select the optimal drug.
    Reaching the strongest antibiotic right away to treat an infection while the more common drug available (and effective) is available (and effective) can be very dangerous (and costly) as MRSP or other bacteria in the body may become resistant and there may be no cure left. that could effectively treat the infection.
  • Topical treatment of skin and soft tissue infections (e.g. incision and irrigation of the abscess) is also often very effective and should not be overlooked, even if the animal is treated with antibiotics in general.
  • Generally, methicillin-resistant staphylococci in dogs are susceptible to mupirocin, rifampicin, linezolid and vancomycin, which are important in human medicine for the treatment of MRSA infections or represent last resort antibacterial agents.
  • Sometimes the MRSP strain can be resistant to almost all available antibiotics, making choosing the right drug extremely difficult.
    In such situations, consultation of your treating physician with an animal infectious disease specialist to determine the best treatment.

Colonization by methicillin-resistant Staphylococcus pseudintermedius strains:

  • There is no information on whether, when or how to eliminate MRSP from colonized animals.
    Since S. pseudointermedius has evolved to live on dogs and cats, decolonization of these animals may be difficult or impossible.
    Decolonization therapy with antibiotics is not recommended for animals that are asymptomatic carriers of MRSP - unlikely to be effective and may lead to further bacterial resistance to antimicrobials.

What should I do if my pet is colonized with mrsp?

  • Avoid contact with your dog's nose, mouth, or anus as these are the most likely areas where staphylococcus may be present.
  • Do not let your pet lick their face or any area of ​​skin (especially an injured one).
  • MRSP positive dogs should be walked in low traffic areas - where there is less chance of encountering other animals and people and of transferring staphylococci by direct contact.
  • MRSP may be present in the stool, so it is extremely important that the stools are removed promptly and disposed of in the bins provided for this purpose.
  • Although the importance of the environment in the transmission of MRSP is unclear, staphylococcus may persist in the environment for some time.
    Toys and dog beds with positive MRSP results should be changed, washed and cleaned regularly to reduce exposure of both animals and humans to MRSP.
    Dirty blankets should be washed separately.
  • It's a good idea to keep MRSP colonized dogs away from people's beds.
  • Hand hygiene remains the most important preventive factor in the transmission of MRSP.

How long will my pet be colonized by mrsp?

There is no information on how long animals remain colonized with MRSP, but long-term colonization is likely possible as S. pseudointermedius is well adapted to living on dogs, unlike MRSA which animals are supposed to carry for a short time if colonized.

What should I do if my pet has mrsp infection?

First of all, calm down.

Although MRSP infections can be very serious, most animals can be treated successfully.

Follow your veterinarian's instructions.

Getting treated right from the start is very important.

Make sure you follow all treatment recommendations.

Always pay attention to the exact dosage and timing of medication.

It is especially important to complete the full course of antibiotic therapy completely, even if the dog is no longer showing any clinical signs and appears to be perfectly healthy.

Avoid contact with the infected area. If possible, the contaminated area or part of the body should be covered or bandaged to reduce the risk of transmission and environmental contamination.

All dressing instructions given by your veterinarian should be followed very carefully.

Wear gloves if you want to change the dressing.

Wash your hands. Hand hygiene with water and soap, or with an alcohol-based hand sanitizer, is the simplest and most practical way to prevent the transmission of MRSP between animals and humans.

In general, colonization of MRSP is rare in healthy pets, but it is possible that your dog is a carrier of this strain.

Therefore, hand hygiene is important for everyone after contact with an animal, and is especially important in people with a weakened immune system. This is especially important after contact with a dog with an active MRSP infection, as the risk of staphylococcal transmission is then greater.

A strict quarantine is not necessary.

MRSP is widespread in the dog population, so aggressive measures to limit exposure to an infected dog are not advisable.

However, common sense should be used to reduce the likelihood of transmission to other dogs and people by:

  • Avoiding large groups of dogs while the dog's infection is still active.
  • During walks, the dog should be under constant control (on a leash) so that it cannot come into contact with other animals.
  • Faeces should be removed immediately after defecation of a sick animal, as staphylococcus may also be present in the faeces.
  • Keep your dog away from people and animals with a weakened immune system.

Assume the bacterium lives on other parts of the animal's body as well, not just where it has an infection.

Therefore, you should also follow the basic hygiene recommendations that also apply to colonized animals.

How can I prevent my dog ​​from infecting my dog ​​with mrsp?

Exposure to MRSP in pets cannot be completely prevented as it is transmitted by a significant number of clinically healthy animals (and also by some healthy individuals).

Pet owners and veterinary staff can be colonized by the MRSP, so staff working in the veterinary clinic should be aware of the risks of hospital MRSP transmission.

Risk factors for MRSP colonization and infection in domestic animals are not well known. One important step in preventing the emergence of MRSP is the judicious and responsible use of antibiotics.

Antibiotics should only be used when there is a real need, preferably after testing the susceptibility of bacteria to antimicrobial drugs.

Always follow the recommendations as scrupulously as possible. Administer the correct dose of antibiotic at the right time and complete the entire course of antibiotic therapy (unless instructed otherwise by your veterinarian).

Only use antibiotics when they are really needed and only after your veterinarian recommends them.

The prophylactic use of antibiotics should be avoided.

It is also necessary to follow strict hygiene procedures to prevent the transmission of MRSP.

Staphylococcus intermedius and the controversy related to its classification

What is mrsi and staphylococcus intermedius?

Staphylococcus intermedius is a bacterium very closely related to Staphylococcus pseudintermedius.

MRSI is a methicillin resistant Staphylococcus intermedius strain, as is MRSP.

Staphylococcus intermedius was previously considered the most important species of staphylococcus in dogs and cats. In recent years it has been established that what was previously identified as Staphylococcus intermedius is in fact a species of Staphylococcus pseudintermedius, and S itself. intermedius is, in fact, extremely rare.

To distinguish S. intermedius from S. pseudointermedius, it is necessary to perform molecular tests. Since identification is so difficult, some laboratories still report the isolation of S. intermedius from dogs and cats.

It is almost certain that these bacteria are actually S. pseudointermedius.

Fortunately, this distinction has no bearing on how infections are treated with these staphylococci.

Since in older literature sources the species S. intermedius is described as the main cause of dermatological diseases in dogs, it should be corrected that it is probably the S species. pseudointermedius.

Unfortunately, at present - apart from mentioning the isolation of this staphylococcus from city pigeons - there is little data on the presence of the species Staphylococcus intermedius in animals

Staphylococcus pseudointermedius was first described as a new coagulase-positive species in 1976 (at that time it was still called S. intermedius).

It is a component of the normal canine microflora and is also a major opportunistic pathogen responsible for common canine skin infections.

NS. pseudointermedius has also been found in many other animals and can sometimes cause severe infections in humans.

As I mentioned in the description of this pathogen, the approach to identifying this species has changed in recent years.

Independent research groups have shown that isolates phenotypically identified as Staphylococcus intermedius consist of three different species, including S. intermedius, S. pseudointermedius and S. delphini, which together represent the group S. intermedius (SIG - Staphylococcus intermedius group).

Importantly, it was discovered that it was S. pseudointermedius and not S. intermedius is a common etiological agent of pyoderma in dogs and that S. delphini may be of greater clinical importance than previously thought.

Other species of staphylococci isolated from humans and animals

Staphylococcus schleiferi

Staphylococcus schleiferi subsp. coagulans, a coagulase positive bacterium, is less likely to cause pyoderma and otitis externa in dogs and cats.

This staphylococcus very rarely infects humans.

The phenotypic properties of this staphylococcus are very similar to S. pseudointermedius, therefore it may be mistakenly identified as S. intermedius or S. pseudointermedius.

Staphylococcus schleiferi subsp. schleiferi is a coagulase negative bacterium and therefore may be mistakenly reported by a diagnostic laboratory as "non-pathogenic " if it does not specify the type of bacteria.

This staphylococcus uncommonly causes pyoderma and otitis in dogs, but has a high level of methicillin resistance. However, it is not as multi-drug resistant as MRSP.

This bacterium is part of the normal skin flora in humans and can cause postoperative skin and soft tissue infections. Zoonotic infection S. schleiferi spp. is extremely rare.

Staphylococcus epidermidis is the most common species of bacteria isolated from the surface of the human body.

It is a coagulase-negative staphylococcus, which most often colonizes the skin of the armpits, head and the vestibule of the human nose. Once considered harmless, now it is described as "a microorganism on the verge of pathogenicity and commensalism".

In recent years, there has been an increase in the frequency of infections caused by S. epidermidis.

This may be related to the increasing use of invasive medical equipment, such as: vascular ports, catheters, implants or joint prostheses through which bacteria can spread.

Infections caused by this species of staphylococcus mainly affect people with reduced immunity, e.g. patients undergoing chemotherapy, transplant patients, chronically ill or the elderly.

NS. epidermidis is responsible for approximately 70% of infections associated with the use of urological and vascular catheters.

Antibiotic resistance among staphylococci

What is antibiotic resistance?

You may have heard about the rise in antibiotic resistance in the last few years or so.

It has created a rather embarrassing challenge in the treatment of bacterial infections in both human and veterinary medicine.

The trouble is that bacteria acquire certain characteristics that protect them against antibiotics previously thought to be effective.

Increasing resistance to antibiotics among staphylococci is an undesirable and, unfortunately, more and more frequent phenomenon.

A clinically significant problem with the treatment of staphylococcal infections is resistance to beta-lactam antibiotics.

Resistance is due to the presence of the mecA gene within the staphylococcal casette chromosome mec (SCCmec) and strains carrying this gene are called MRSP (methicillin-resistant Staphylococcus pseudointermedius) and, like MRSA (methicillin-a-resistant Staphusylococcus) drug-resistant, due to the fact that SCCmec often contains - in addition to beta-lactam resistance genes, also genes for resistance to other antibiotics and chemotherapeutic agents.

Staphylococcal resistance to different types of antibiotics:

  • Resistance of isolated staphylococci from animals to rifampicin has been observed very rarely.
  • Resistance to first-generation cephalosporins (cephalexin, cefadroxil), β-lactam antibiotics, synthetic penicillins (oxacillin, dicloxacillin, amoxicillin with clavulanic acid), gentamicin, tobramycin, enrofloxacin, and less polympirocin, is mupirocin less than polympirocin, mupirocin 5%.
    If staphylococcal infection is suspected, and there are no results of culture and antibiotic susceptibility testing, they should be antibiotics of first choice.
  • Resistance to sulfonamides with trimethroprim, chloramphenicol, and tyrosine is relatively rare (6-19% of isolates).
  • Resistance to lincomycin, clindamycin and erythromycin is more frequent (20-37% of isolates).
  • Resistance to penicillin, ampicillin, amoxicillin, neomycin and tetracyclines is most common (40-83% of isolates).
    These antibiotics should not be used to treat staphylococcal infections, unless the isolates are susceptible to them or there is no evidence of β-lactamase production.

Methicillin-resistant Staphylococcus pseudointermedius (MRSP) is the most common species of penicillin-resistant Staphylococcus that occurs in small animals.

MRSP is often resistant to many drugs.

This resistance of MRSP strains to so many drugs is a very serious problem in veterinary medicine.

Methicillin resistance is generally associated with resistance to:

  • sulfamethoxazole with trimethoprim,
  • gentamicin,
  • erythromycin,
  • clindamycin,
  • fluoroquinolones,
  • tetracycline.

North American strains have been found to be frequently susceptible to chloramphenicol, rifampicin and amikacin, but chloramphenicol resistance is more common in Europe and susceptibility to minocycline.

An interesting fact is that canine Staphylococcus aureus isolates are more resistant to antibiotics than S. pseudointermedius.

Where did antibiotic resistance come from?

It is well known that increasing resistance to antimicrobials is associated with the widespread use or even abuse of these antibiotics in veterinary practice.

Antimicrobial drugs are often prescribed "exaggerated ", "just in case " or "protectively ".

In many cases, it is indeed necessary to introduce an antibiotic prophylactically, but it requires careful consideration and case studies.

The most common causes of antimicrobial treatment in dogs are:

  • skin and wound infections,
  • otitis externa,
  • respiratory infections
  • urinary tract infections.

In recent years, particular attention has been paid to the resistance to antibacterial agents of bacteria derived from animals and animal products.

Staphylococci isolated from animals are considered relatively sensitive to antimicrobial agents.

However, antimicrobial susceptibility studies revealed a significant increase in the prevalence of methicillin-resistant staphylococci isolated from animals.

Since the same antibacterial drugs are used in animals as are used to treat human infections, the increasing tendency of antibiotic resistance in bacteria that cause human infections is pivotal to the increasing antibiotic resistance of animal strains.

Therefore, it is extremely important that, instead of empirical treatment of animal infections with antibiotics, a bacteriological test to determine antibiotic resistance is performed.

Staphylococcus aureus strains that are resistant to many antibiotics pose a huge threat to public health and make it difficult to treat humans and animals.

Staphylococcal infections in dogs

Staphylococcal infections in dogs

Pathogenesis of staphylococcal infections

Knowledge of the pathogenesis of infections caused by staphylococci is still incomplete.

There are certainly many underlying causes that predispose dogs to develop a purulent skin infection, but there is no known specific disorder that allows staphylococci, nor is there a single bacterial element that contributes to the development of the disease and tissue damage.

The virulence of microbes can be a factor in whether or not you develop disease.

It depends on the presence of specific components of the bacterial cell envelope, enterotoxins and enzymes, which, together or separately, can cause a wide variety of effects in the host organism and, consequently, allow the invasion of the bacteria into the tissues.

Staphylococci from the group of Staphylococcus pseudointermedius isolated from sick and healthy dogs were tested and there was little genetic differentiation between these strains.

It was also impossible to determine whether the dog's organisms are inhabited by subpopulations of virulent and non-virulent staphylococci.

Staphylococcal bacteria can produce various exotoxins that affect an animal's immune system.

Coagulase is an enzyme of major clinical importance produced by most staphylococci.

It binds fibrinogen and cuts the plasma.

Staphylococcus aureus, S. pseudointermedius and three other staphylococcal species often produce coagulase and are usually more pathogenic than species that do not.

However, coagulase-negative staphylococci, which are components of the normal bacterial flora, are also capable of causing disease in immunocompromised animals or animals with an underlying underlying disease.

Protein A, an extracellular or bacterial cell related protein produced by certain S strains. pseudointermedius may increase the virulence of germs.

The polysaccharide complex of the capsule and the carbohydrate layer covering the cell surface (glycocalyx) produced by many strains of staphylococci may also increase virulence.

Staphylococci have the ability to bind biological materials used in surgery as implants, which often leads to systemic infection.

An important factor influencing the development of such an infection is the ability of Staphylococcus epidermidis to survive in macrophages.

In endocarditis, the disease-causing staphylococci have been shown to produce bacterial agents such as adhesins and toxins that allowed for intracellular invasion and binding to the endocardial surface.

Plasmids that can carry genes responsible for virulence and resistance to:

  • penicillin,
  • ampicillin,
  • amoxicillin,
  • lincomycin,
  • erythromycin,
  • tetracyclines,
  • chloramphenicol,
  • cephalosporins,
  • kanamycin,
  • gentamicin.

Other staphylococcal strains rarely have plasmids and in most cases it is the chromosomal genes that are responsible for antibiotic resistance.

In dogs with severe pyoderma, staphylococci that are resistant to multiple antibiotics are occasionally isolated.

As a rule, these dogs have previously been treated with many antibacterial agents.

How microbes inhabit the body?

In dogs, Staphylococcus pseudointermedius is the dominant species of staphylococci among all bacteria included in the normal microflora.

Most often it inhabits the skin and mucous membranes.

Bitches pass staphylococcus to puppies within 8 hours after giving birth.

Initially, the mucosa of the oral and nasal cavity is inhabited, then the bacteria are deposited on the skin of the abdomen.

Interestingly, the intensity of colonization in bitches has an impact on the level of colonization in puppies.

Many bacterial genotypes are transferred to puppies, but only one or two are dominant and persist.

In adult dogs, staphylococci are found in moist areas such as the nasal mucosa, anus, and more covered areas such as the spaces between the fingers, the ear canal.

These types of large populations do inhabit these sites, unlike the smaller populations of bacteria that are found on the surface of the skin and hair of the back of the body (they rather indicate contamination or transient colonization).

Staphylococci at the end of the hair are contaminants, most often originating from the mucous membrane population.

The mucosa is believed to be the site of contamination for the skin.

Dogs with purulent skin infection have a much higher S population density. pseudointermedius in mucous membranes than other healthy domestic animals.

Additional evidence that the mucosa is the main habitat of staphylococci and that the infection spreads from them is the fact that after reducing the number of bacteria on the mucosa (after administering fusidic acid to the mucous membranes), the population of bacteria on the skin decreased.

What diseases can cause staphylococcal infections in dogs?

Coagulase-positive staphylococci are most often isolated from the body integuments of dogs with pyoderma.

They can attack any organ or organ, but most often they are detected in abscesses and infections of the skin, eyes, ears, respiratory and genitourinary tract, bones and joints.

The most frequently isolated species of canine staphylococcus is Staphylococcus pseudointermedius, which is detected in:

  • pyoderma,
  • inflammation of the outer ear,
  • inflammation of the bones and spine,
  • bacteremia,
  • conjunctivitis,
  • urolithiasis,
  • as well as in inflammation of the heart valves and pericarditis.

Staphylococci can also accompany many other disease states, such as. skin burns, toxic shock or fasciitis.

How are staphylococcal infections diagnosed?

Staphylococcal infections are diagnosed on the basis of:

  • Initial cytological examination of smears taken from the ear canal, skin or mucous membranes, or by spot biopsy of pustules, boils or abscesses. The examination shows neutrophils and cocci arranged (singly or in pairs) in short chains or rare, irregular clusters.
  • Bacteriological examination of samples taken by smear or point biopsy.
  • Bacteriological blood tests or urine tests.
  • Bacteriological examination of respiratory aspirates.
  • Bacteriological examination of the biopsy taken from deeply located places (e.g. bone fragments from cases of discospondylosis).

Staphylococci in collected specimens survive up to 48 hours if stored at low temperature (4 ° C) and if collected on an appropriate transport medium.

Due to the increasing occurrence of pathogenic strains of methicillin-resistant staphylococci (MRSP and MRSA) in dogs, it becomes necessary to accurately identify species within this group of staphylococci.

There are certain biochemical features of coagulase positive staphylococci isolated in dogs that allow the initial identification of S. pseudointermedius, however, none of the phenotypic features allows proper identification of the species in the SIG group.

Final identification is made through the use of molecular biology methods.

In practice - in order to facilitate the work of laboratories - it was assumed that staphylococcal strains derived from dogs with phenotypic features considered typical for the species S. intermedius can be recognized as S. pseudointermedius without performing additional molecular tests.

The justification for this is the fact that other species from the SIG group are practically non-existent in dogs.

In turn, staphylococci isolated from other animal species with the phenotypic features of S. intermedius can only be recognized as belonging to the SIG group (unless molecular diagnostics are performed).

Genetic typing methods within the species of S. pseudointermedius:

  • pulsed field gel electrophoresis (PFGE) technique;
  • typing and determining the nucleotide sequence of fragments of selected genes of the multilocus sequence typing (MLST);
  • "Spa-typing " - typing based on the polymorphism of repetitive regions of the spa gene encoding protein A;
  • for methicillin-resistant strains, the type of staphylococcal SCCmec cassette is determined.

Detection of methicillin resistance in S. pseudointermedius is performed using phenotypic and genotypic methods.

Medications for staphylococcus in dogs

The following antibiotics are used to treat staphylococcal infections:

  • amoxicillin with clavulanic acid at a dose of 12.5-20 mg / kg m.c. orally every 8-12 hours;
  • oxacillin at a dose of 22 mg / kg m.c. orally every 8 hours;
  • cefalexin or cefadroxil at a dose of 22 mg / kg m.c. every 12 hours;
  • clindamycin 11 mg / kg m.c. orally every 24 hours;
  • quinolones (e.g. enrofloxacin) at a dose of 5 mg / kg m.c. orally every 24 hours;
  • Erythromycin at a dose of 10-15 mg / kg m.c. orally every 8 hours;
  • chloramphenicol at a dose of 15-25 mg / kg m.c. orally, intravenously or subcutaneously every 8 hours;
  • sulfonamides with trimethoprim at a dose of 22 mg / kg m.c. orally every 12 hours.

If your dog has deep pyoderma and has been previously treated with antibiotics for staphylococcal infection, it will need to be cultured.

Staphylococcus pseudointermedius strains sensitive to methicillin are usually well treated with commonly used antibiotics and chemotherapeutic agents.

Although there is resistance to penicillin and amoxicillin, they usually respond well to cephalosporins, amoxicillin with clavulanic acid, fluoroquinolones, clindamycin and sulfonamides.

The situation is different in the case of diseases caused by methicillin-resistant Staphylococcus pseudintermedius strains, which are characterized by multi-drug resistance.

Here it is necessary to select the appropriate drug based on the results of the antibiogram.

In the treatment of infections caused by methicillin-resistant Staphylococcus pseudintermedius strains, the following may be effective:

  • rifampicin,
  • minocycline,
  • chloramphenicol,
  • amikacin,
  • vancomycin.

However, many of these drugs are not licensed for veterinary use or are not licensed for dogs and cats.

In addition, the World Health Organization (WHO) has published a document on microbial resistance in which some of the drugs that are effective in treating MRSP infections are classified as. extremely important antibiotics that should be reserved exclusively for use in human medicine.

Resistance to vancomycin has not yet been documented in veterinary medicine, but the WHO position mentioned earlier is of great importance; therefore it is believed that the use of vancomycin should be reserved for the treatment of human infections caused by MRSA strains.

The drug linezolid has not yet been reported to be resistant to Staphylococcus pseudintermedius strains, but it is also mainly used to treat MRSA infections in humans.

There is no ban on its use in veterinary medicine, so it can be used to effectively treat MRSP infections in dogs.

Its disadvantage is the high price.

Threat to public health

Due to the possible transmission of bacteria to humans, staphylococcal infections in animals pose a threat to public health.

It is associated mainly with animals used for food production, but the colonization of companion animals by different species of staphylococci is also of great importance.

Staphylococcal infections also contribute to serious economic losses, especially in the dairy industry.

Staphylococcus aureus, being the main etiological factor of mastitis, penetrates the milk of cows and other ruminants.

One of the most important threats to public health, however, is antibiotic resistance.

It lowers the effectiveness of treatment, increases its costs, and additionally creates the risk of therapy failure in the case of such medical procedures as:

  • transplants,
  • cancer chemotherapy,
  • surgical procedures.


Staphylococci in dogs are usually a physiological element of the cutaneous and mucosal microflora, posing no threat to the health of the animal or humans.

However, because they have the potential to cause infections, especially in sick or debilitated individuals, basic rules of personal hygiene (hand washing) and hygiene of rooms and equipment (cleaning, disinfection) should be followed.

Thanks to this, we will significantly reduce the possibility of transmitting bacteria between animals and humans.

What staphylococci are most often detected in dogs?

The most frequently isolated species of canine staphylococcus is Staphylococcus pseudointermedius.

Can people get MRSP?

Yes, but it seems quite rare.

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