Feline Otitis Externa Caused by Methicillin-Resistant <i>Staphylococcus aureus</i> with Mixed Hemolytic Phenotype and Overview of Possible Genetic Backgrounds

• Main Authors: Jana Avberšek (Author), Bojan Papić (Author), Darja Kušar (Author), Vladimira Erjavec (Author), Katja Seme (Author), Majda Golob (Author), Irena Zdovc (Author)
• Format: Book
• Published: MDPI AG, 2021-05-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) is an important cause of nosocomial infections in humans, but its importance in small animal practice is increasing. Here, we present a case of feline otitis externa (OE) caused by MRSA; both hemolytic and nonhemolytic variants with a stable phenotype were recovered from the external auditory canal after infection was detected by routine otoscopy. One isolate per variant underwent antimicrobial susceptibility testing (AST) by broth microdilution method, conventional <i>spa</i> typing and whole-genome sequencing (WGS). The results showed that both variants were genetically related and were of sequence type (ST) 1327, SCC<i>mec</i> type IV and <i>spa</i> type t005. AST and WGS showed that both isolates were resistant to β-lactams and sensitive to all tested non-β-lactam antibiotics. Both isolates were <i>pvl</i>-negative, but encoded several other virulence genes (<i>aur</i>, <i>hlgABC</i>, <i>sak</i>, <i>scn</i>, <i>seg</i>, <i>sei</i>, <i>sem</i>, <i>sen</i>, <i>seo</i> and <i>seu</i>). Genetic background of the mixed hemolytic phenotype was not identified; no differences in the <i>agr</i> locus or other regulatory regions were detected. Three single-nucleotide polymorphisms were identified but could not be associated with hemolysis. This well-documented case of MRSA infection in companion animals adds to the reports of MRSA infections with a mixed hemolytic phenotype.

Item Description

10.3390/antibiotics10050599
2079-6382