Frequency, Distribution, and Antimicrobial Resistance of Coagulase-Negative Staphylococci Isolated from Clinical Samples in Dogs and Cats

Abstract

This study aimed to investigate the frequency, distribution, and antimicrobial resistance of coagulase-negative staphylococci (CoNS) obtained from clinical samples from dogs and cats and to classify any methicillin-resistant CoNS (MRCoNS). The samples were collected in 2017-2018, and species identification and antimicrobial susceptibility testing were routinely performed using the Vitek2 system. Among 1,056 staphylococci, 185 CoNS (17.5%) were obtained and included 18 species from dogs (<i>n</i> = 116) and 14 species from cats (<i>n</i> = 69). The predominant species were <i>Staphylococcus chromogenes</i> (31.4%)<i>, Staphylococcus hominis</i> ssp. <i>hominis</i> (16.2%), <i>Staphylococcus warneri</i> (10.8%), and <i>Staphylococcus epidermidis</i> (8.1%). The primary isolation sites were the skin and urinary tract. High levels of resistance to β-lactams (65.4%), tetracycline (44.3%), clindamycin (36.8%), and erythromycin (30.8%) were observed. Twenty-five MRCoNS (13.4%), mainly <i>Staphylococcus haemolyticus</i> (<i>n</i> = 8), <i>S. epidermidis</i> (<i>n</i> = 6), and <i>S. hominis</i> ssp. <i>hominis</i> (<i>n</i> = 5), were identified. SCC<i>mec</i> type V (<i>n</i> = 8) was the most common type, followed by SCC<i>mec</i> type IV (<i>n</i> = 6) and SCC<i>mec</i> type III (<i>n</i> = 2), whereas nontypable SCC<i>mec</i> were classified into nine MRCoNS. Some CoNS have been recorded in humans, and these might be transferred to and cause subsequent infections in humans. Moreover, the diversity of SCC<i>mec</i> types and resistant strains suggested that they may serve as a reservoir of resistance genes among staphylococci.