Diversity of staphylococcal cassette chromosome in coagulase-negative staphylococci from animal sources

Abstract

Aims: To type the staphylococcal cassette chromosome (SCC) in coagulase‐negative staphylococci (CoNS) from animal sources. Methods and Results: A total of 92 CoNS isolates recovered from farm animals was analysed. The top three staphylococcal species were Staphylococcus lentus (34), S. sciuri (31), and S. xylosus (13). The presence of the cassette chromosome recombinase (ccr) genes ccrA1, ccrB1, ccrA2, ccrB2, ccrA3, ccrB3 and ccrC, the mec regulatory genes mecI and mecR1, and Tn554 was used to differentiate the SCC. A total of 60 of the 92 isolates were methicillin resistant. Among the 60 methicillin‐resistant Staphylococcus spp. isolates, SCCmec (mecA‐carrying SCC) types I, III, IV and V were identified in 24 isolates based on the combinations of the ccr genes and the mec regulatory genes, with type III being predominant. The single S. epidermidis carried SCCmec type IV. SCC type III was also identified in two of 32 methicillin‐susceptible isolates. Identical SCCmec types were present in different species of CoNS. Pulsed‐field gel electrophoresis (PFGE) generated 64 patterns out of 81 PFGE typeable isolates. Indistinguishable clones were detected in animals from different farms. Conclusions: Heterogeneous SCC existed in CoNS of diverse genetic background. Both clonal transmission of methicillin‐resistant CoNS and horizontal transfer of SCCmec occurred in the animal production environment. Significance and Impact of the Study: This study adds to our knowledge of SCCmec type and the diversity of SCC in CoNS.

Antimicrobial susceptibility pattern and SCCmec types of methicillin-resistant coagulase-negative staphylococci from subclinical bovine mastitis in Hatay, Turkey

“…The study conducted in Germany by Feßler and Billerbeck (3), in which genotypic and phenotypic tests were applied in order to investigate methicillin-resistance in CoNS isolates from bovine mastitis, also reported that some CoNS isolates exhibiting oxacillin resistance (MICs, ≥0.5 µg/mL) did not harbour the mecA gene. Misestimation of methicillin-resistance in CoNS by phenotypic tests has been also reported by other investigators (19,24). The mecA positive CoNS from a variety of animal species have been isolated so far, and the prevalence of mecA positive CoNS obtained from subclinic mastitis in this study was found to be similar to the results of previous studies conducted in European countries (3,19), but higher than that reported by Ünal and Çınar (22) in Turkey.…”

“…In this study, even though 21 (23.6%) isolates demonstrated resistance to oxacillin by broth microdilution method, only 13 (14.6%) were considered as methicillin-resistant because detection of the mecA gene is the best tool for identification of methicillin-resistant isolates (24). The study conducted in Germany by Feßler and Billerbeck (3), in which genotypic and phenotypic tests were applied in order to investigate methicillin-resistance in CoNS isolates from bovine mastitis, also reported that some CoNS isolates exhibiting oxacillin resistance (MICs, ≥0.5 µg/mL) did not harbour the mecA gene.…”

“…However, the emerging antimicrobial resistance to these agents limits the use of this antimicrobials, and causes overuse of other agents such as glycopeptides. Thus, several studies have been conducted to examine the presence of mecA gene encoding PBP2a among CoNS isolates from the mastitis (10,19,24).…”

Methicillin-Resistant Staphylococcus aureus (MRSA) in Food- Producing and Companion Animals and Food Products

“…For instance, ST398 appears to have evolved by multiple acquisitions of the SCCmec elements, such as SCCmec types II, III, IV, IVa, and V [176]. In the Netherlands, two farms were found to have MRSA ST398 with identical spa types, but diferent SCCmec types, suggesting that divergent SCCmec elements were inserted into the clonal MSSA [57].…”

“…Similarly, MSSA ST398 (spa type t899), MRSA ST398-IVa (spa type t899), and MRSA ST398-V (spa type t108) were found in dust samples, nasal swabs, and a blood isolate from workers on the same pig farm [177], suggesting multiple acquisitions of SCCmec cassetes by MSSA precursors. Coagulase-negative staphylococci in the farming environment are suspected as sources of SCCmec [176], and the progeny of emerging MRSA strains are spreading locally rather than globally [178][179][180]. While SCCmec acquisition seems to be fairly common in MRSA ST398, the transfer of staphylococcal toxin genes, including the Panton-Valentine leukocidin gene (pvl) appears to be rarer [ …”