Methicillin-resistant Staphylococcus lentus strains isolated from chicken carcasses and employees of a poultry abattoir

Methicillin-resistant coagulase-negative staphylococci (MR-CNS) are increasingly reported in animals and humans as colonizing organisms and as opportunistic pathogens. Within a collection of MR-CNS isolates from livestock, chicken carcasses, bulk tank milk, minced meat, and contact persons, matrix-assisted laser desorption ionization-time of flight mass spectrometry identified 37 isolates as S. lentus. All 37 methicillin-resistant S. lentus strains originated from either chicken carcasses (30 strains) or employees working in a poultry abattoir (seven strains). To assess the phenotypic antibiotic resistance to selected antibiotics (ciprofloxacin, clindamycin, erythromycin, gentamicin, rifampin, sulfamethoxazole/trimethoprime, tetracycline, vancomycin), the disk diffusion method was used and none of the strains was resistant to gentamicin, rifampin, or vancomycin. Pulsed-field gel electrophoresis (SmaI) was applied to evaluate the genotypic relationship of the 37 methicillin-resistant S. lentus strains. With a cut-off level of 80 % similarity, 30 (81.1 %) strains were grouped into only two clusters. Overall, the seven human strains showed between 85 % and 100 % similarity to the closest related chicken isolates. Our results suggest potential transmission of methicillin-resistant S. lentus between slaughtered chickens and abattoir personnel.