however, pbp2a encoded by the meca gene have reduced affinity for, and thus is not inhibited by, most beta-lactam antibiotics thus conferring resistance against most beta-lactam antibiotics. staphylococcus schleiferi has also shown resistance to fluoroquinolones, including second and third generation fluoroquinolones, but may retain susceptibility to fourth generation fluoroquinolones. this resistance was associated with changes in the gyra gene which encodes for dna gyrase subunit a, resulting in less susceptibility of the enzyme to fluoroquinolones. enterotoxins and exoenzymes many staphylococcal species produce enterotoxins which have known pyrogenic and emetic effects. pcr analysis has detected the presence of enterotoxin producing genes sed and elisa methods have shown the production of the corresponding staphylococcal enterotoxin sed by s. schleiferi. sed is thought to be one of the most common enterotoxins produced by staphylococcus spp. associated with food poisoning. s. schleiferi also produce staphylococcal enterotoxins sea, seb, sec and toxic-shock syndrome toxin (tsst-1). enterotoxins sea and seb are known emetics in primates and, with tsst-1, cause toxic shock syndrome with acute intoxication. staphylococcus schleiferi also possess the ability to produce numerous exoenzymes such as alpha and delta toxins, dnase, lipase, esterase, and protease which may also contribute to its virulence or serve as aggressins. a beta-like toxin similar in structure and functionality to the beta-toxin of s. aureus has also been described in s. schleiferi. disease diseases of dogs and cats staphylococcus schleiferi is most commonly identified as a pathogenic bacteria of companion animals (primarily dogs and cats). staphylococcus schleiferi rarely causes disease in cats, and it is more commonly associated with inflammatory conditions of dogs. staphylococcus schleiferi can be involved in conditions of pyoderma, otitis externa, and otitis media in both dogs and cats. pyoderma staphylococcus schleiferi is one of the causative agents in pyoderma of dogs and cats. pyoderma is a skin infection characterized by the presence of purulent discharge (pus). dogs are most commonly affected by this skin infection which may be caused by a bacterial infection or sometimes, but less commonly, a fungal infection. staphylococcus schleiferi along with staphylococcus aureus and staphylococcus pseudintermedius are the most common bacteria that cause pyoderma in dogs. staphylococcus schleiferi is more commonly found in cases of pyoderma with dogs suffering from reoccurring pyoderma who have already undergone antimicrobial treatment. staphylococcus pseudintermedius and staphylococcus aureus are more commonly found to be the cause of pyoderma in dogs who are experiencing the infection for the first time. the symptoms of pyoderma include: pruritus (severe itchiness); dermatitis (general skin irritation); alopecia (hair loss); scaling/scabbing; and bloody and/or purulent discharge. when treating a dog with pyoderma related to staphylococcus schleiferi, it is important to avoid administering methicillin and other penicillins, as there is increasing resistance to these antimicrobial therapies. otitis externa a cocker spaniel diagnosed with otitis externa. otitis externa is an inflammatory condition of the outer ear canal that affects many species, including canids. staphylococcus schleiferi has been identified as one of the organisms which contributes to otitis externa in dogs and less commonly in cats. otitis externa is the most common disorder of the ear canal of dogs. clinical signs of otitis externa include: head shaking, alopecia (hair loss), erythema (reddening of the skin), and pruritus (itchiness). there appears to be a higher incidence of otitis externa in young dogs (1–5 years of age) as compared to older dogs (>5 years of age). there is also disposition to otitis externa in certain breeds, including: cocker spaniels, golden retrievers, and west highland white terriers. treatment of otitis externa depends on the cause. there are multiple organisms that may cause this inflammation and infection of the ear canal. treatment plans should be decided based on bacterial identification and susceptibility profiles. otitis media staphylococcus schleiferi has been identified as a contributor to otitis media in dogs and less commonly cats. otitis media is a condition of inflammation of the middle ear canal. otitis media is concurrently present in many of the cases of dogs diagnosed with otitis externa. if otitis media is not diagnosed and treated, it can lead to otitis externa. signs of otitis media include: head shaking, vestibular signs (head tilt), and scratching of the effected ear. diagnosis of otitis media is more challenging than with otitis externa because access to the middle ear canal can be challenging. following diagnosis, bacterial identification is required and susceptibility testing on the bacteria is warranted to guide the microbial treatment plan. surgery is a treatment option when antimicrobial treatment fails to resolve the clinical signs associated with otitis media. diseases of humans staphylococcus schleiferi has rarely been described as a human pathogen, but there are some case reports and case series reports that describe the correlation between isolation of staphylococcus schleiferi and surgical site and wound infections. staphylococcus schleiferi has been described as the causative agent of surgical site and wound infections; pediatric meningitis; endocarditis; and intravascular device-related bacteremia in case reports and case series reports: surgical site and wound infections staphylococcus schleiferi has been described in a clinical case series report as causing infections at surgical sites post-operatively. pediatric meningitis illustration of endocarditis on a heart valve. meningitis refers to inflammation of the meninges. staphylococcus schleiferi has been identified as the causative agent of meningitis in a child (6 years old) and an infant (2 months old) in case reports. endocarditis endocarditis refers to inflammation of the endocardium of the heart. staphylococcus schleiferi was isolated as the cause of endocarditis of a prosthetic valve in a case report involving a 78-year-old man. intravascular device-related bacteremia in a case report describing a 55-year-old female who had recently had a left ventricular assist device placed, staphylococcus schleiferi was identified as the causative agent of bacteremia. a second case was described involving a 58-year-old male who had undergone a liver transplant and subsequently developed staphylococcus schleiferi aortic valve endocarditis. diagnosis a swab collected from the area of interest is regularly taken because staphylococcus schleiferi is often associated with superficial infections of the skin for people and skin or ears for animals. sample collection does depend on the site of interest and so an appropriate specimen is obtained based on the area of infection, such as a cystocentesis for urinary tract infections. the initial step of gram staining assists in distinguishing the characteristic gram-positive cocci in clusters for staphylococcus species. it is then cultured on blood agar as non-pigmented round colonies that are beta-hemolytic meaning there is complete clearing of the red blood cells. staphylococcal species are typically differentiated based on their coagulation reaction but because staphylococcus schleiferi is a coagulase variable species, meaning it can appear positive or negative on coagulase testing depending on the subtype, additional biochemical tests are needed to be performed. further testing may include polymerase chain reaction (pcr) and matrix-assisted laser desorption ionization time of flight mass spectrometry (maldi-tof ms). pcr amplifies dna for identification whereas maldi-tof uses both the mass and charge of molecules to acquire a unique peptide mass fingerprint (pmf). the pmf is matched to a database of known microbial isolates, but this database is a limitation as the database must contain the pmf for the tested organism. maldi-tof ms has been reliable for distinguishing s. schleiferi from other staphylooccus species but not for identifying subspecies like schleiferi and coagulans. clinically, subspecies identification is commonly not done as treatment is based on susceptibility testing and location of the infection.