Evaluation of Clinical Laboratory Standards Institute Interpretive Criteria for Methicillin-Resistant <i>Staphylococcus Pseudintermedius</i> Isolated from Dogs

Schissler, Jennifer R.; Hillier, Andrew; Daniels, Joshua B.; Cole, Lynette K.; Gebreyes, Wondwossen A.

doi:10.1177/104063870902100514

Cited by 62 publications

(59 citation statements)

References 22 publications

(34 reference statements)

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“…The oxacillin breakpoints used to confirm methicillin resistance were a MIC of Ն0.5 g/ml and a disk diffusion zone of inhibition of Յ17 mm. These breakpoints were adopted by the clinical microbiology laboratory following recognition that the CLSI standards published in 2008 failed to identify some MRSP isolates (13,14). Any isolate in which at least two of the three tests indicated methicillin resistance was deemed MRSP.…”

Section: Bacterial Isolatesmentioning

confidence: 99%

Amikacin Resistance in Staphylococcus pseudintermedius Isolated from Dogs

2014

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bStaphylococcus pseudintermedius is the most common microorganism isolated from canine pyoderma and postoperative wound infections. The prevalence of methicillin-resistant S. pseudintermedius (MRSP) has increased, and recently, isolates that are resistant not only to methicillin but also to other classes of antibiotic drugs, including aminoglycosides, have become common. A total of 422 S. pseudintermedius isolates collected from 413 dogs were analyzed for amikacin and methicillin resistance using broth microdilution and disk diffusion testing. Methicillin-resistant isolates were significantly (P < 0.0001) more likely to be resistant to amikacin (37%, 31/84) than were methicillin-susceptible isolates (7%, 22/338). Additionally, resistance to non-␤-lactam antibiotics was significantly associated with resistance to amikacin irrespective of methicillin resistance. Among the 422 isolates, 32 that tested positive for amikacin resistance by broth microdilution or disk diffusion testing were investigated further for the presence of aminoglycoside-modifying enzyme genes using multiplex PCR. Of these isolates, 66% (21/32) were methicillin resistant. In contrast to previous studies of Staphylococcus aureus, the most prevalent gene detected was aph(3=)-IIIa found in 75% (24/32) of isolates followed by aac(6=)/aph(2؆) and ant(4=)-Ia in 12% (4/32) and 3% (1/32), respectively. Understanding the differences in antimicrobial resistance gene carriage between different species of Staphylococcus may improve antimicrobial drug selection for clinical therapy and provide insights into how resistance develops in S. pseudintermedius.

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Section: Bacterial Isolatesmentioning

confidence: 99%

Amikacin Resistance in Staphylococcus pseudintermedius Isolated from Dogs

2014

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“…However, the incidence of methicillin-resistant S. pseudintermedius (MRSP) in dogs has increased, presenting a major treatment challenge for veterinarians (21). In face of this emerging resistance, the Clinical and Laboratory Standards Institute (CLSI) veterinary group revised recommendations for the detection of methicillin resistance in these isolates (22)(23)(24) and now stipulates that oxacillin disk or MIC testing be performed and interpreted by using S. pseudintermedius-specific breakpoints (Table 1). These guidelines are found in the CLSI VET01-S2 document (25).…”

mentioning

confidence: 99%

Evaluation of Oxacillin and Cefoxitin Disk and MIC Breakpoints for Prediction of Methicillin Resistance in Human and Veterinary Isolates of Staphylococcus intermedius Group

Burnham

Westblade

et al. 2016

J Clin Microbiol

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Staphylococcus pseudintermedius is a coagulase-positive species that colonizes the nares and anal mucosa of healthy dogs and cats. Human infections with S. pseudintermedius range in severity from bite wounds and rhinosinusitis to endocarditis; historically, these infections were thought to be uncommon, but new laboratory methods suggest that their true incidence is underreported. Oxacillin and cefoxitin disk and MIC tests were evaluated for the detection of mecA-or mecC-mediated methicillin resistance in 115 human and animal isolates of the Staphylococcus intermedius group (SIG), including 111 Staphylococcus pseudintermediusand 4 Staphylococcus delphini isolates, 37 of which were mecA positive. The disk and MIC breakpoints evaluated included the Clinical and Laboratory Standards Institute (CLSI) M100-S25 Staphylococcus aureus/Staphylococcus lugdunensis oxacillin MIC breakpoints and cefoxitin disk and MIC breakpoints, the CLSI M100-S25 coagulase-negative Staphylococcus (CoNS) oxacillin MIC breakpoint and cefoxitin disk breakpoint, the CLSI VET01-S2 S. pseudintermedius oxacillin MIC and disk breakpoints, and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) S. pseudintermedius cefoxitin disk breakpoint. The oxacillin results interpreted by the VET01-S2 (disk and MIC) and M100-S25 CoNS (MIC) breakpoints agreed with the results of mecA/mecC PCR for all isolates, with the exception of one false-resistant result (1.3% of mecA/ mecC PCR-negative isolates). In contrast, cefoxitin tests performed poorly, ranging from 3 to 89% false susceptibility (very major errors) and 0 to 48% false resistance (major errors). BD Phoenix, bioMérieux Vitek 2, and Beckman Coulter MicroScan commercial automated susceptibility test panel oxacillin MIC results were also evaluated and demonstrated >95% categorical agreement with mecA/mecC PCR results if interpreted by using the M100-S25 CoNS breakpoint. The Alere penicillin-binding protein 2a test accurately detected all mecA-positive isolates, although for four isolates, cefoxitin induction was required prior to testing. These data demonstrate that the cefoxitin surrogate test does not reliably detect the presence of mecA in S. pseudintermedius isolates and that laboratories should perform oxacillin disk or MIC tests of these isolates when they are encountered. Staphylococcus pseudintermedius is a coagulase-positive, hemolytic species that colonizes the nares and anal mucosa of healthy dogs and cats (1-4). Clinically, S. pseudintermedius is the most common cause of canine pyoderma and occasionally causes urinary tract and joint infections in dogs and cats (5-8). Phenotypically, S. pseudintermedius is difficult to differentiate from Staphylococcus intermedius and Staphylococcus delphini, which are also coagulase-positive veterinary staphylococci. Collectively, these three species are referred to as the S. intermedius group (SIG). Differentiation of the members of this group requires molecular analysis (9), although matrix-assisted laser desorption ionization-time of flig...

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“…Studies of S. pseudintermedius from dogs revealed that the oxacillin breakpoint for S. aureus and the cefoxitin disc test in particular cannot reliably identify isolates that carry the mecA gene, which determines resistance mediated by PBP2a (1,14). Thus, in cases of coagulase-positive staphylococci causing zoonotic infection, it is reasonable to apply oxacillin breakpoints recommended for coagulase-negative staphylococci in human infections (MIC Յ 0.25 g/ml [using broth dilution] and/or Ն18-mm zone diameter [using the disc diffusion test]).…”

mentioning

confidence: 99%

Staphylococcus hyicus Bacteremia in a Farmer

et al. 2011

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Bacteria known in animal infectious diseases can cause challenges in human diagnostic laboratories. We present pitfalls in the identification and susceptibility testing of Staphylococcus hyicus , a pathogen that typically causes exudative epidermitis in pigs. In this case, the coagulase-positive staphylococcus isolated from a septic patient was misidentified as Staphylococcus aureus .

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Evaluation of Clinical Laboratory Standards Institute Interpretive Criteria for Methicillin-Resistant Staphylococcus Pseudintermedius Isolated from Dogs

Abstract: Our findings also suggest that cefoxitin disk diffusion is an inappropriate screening test for methicillin resistance of canine S. pseudintermedius.

Cited by 62 publications

References 22 publications

Amikacin Resistance in Staphylococcus pseudintermedius Isolated from Dogs

Amikacin Resistance in Staphylococcus pseudintermedius Isolated from Dogs

Evaluation of Oxacillin and Cefoxitin Disk and MIC Breakpoints for Prediction of Methicillin Resistance in Human and Veterinary Isolates of Staphylococcus intermedius Group

Staphylococcus hyicus Bacteremia in a Farmer

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