Livestock-associated methicillin-resistant coagulase-negative staphylococci in pig in Lamphun Province, Thailand, carrying Type-IX SCCmec element

Abstract

Methicillin-resistant coagulase-negative staphylococci (MRCNS) are important opportunistic pathogens of nosocomial infections. An increase in reports of MRCNS in livestock, especially pigs and the evidences of transmission between domestic animals and humans pose a significant public health concern worldwide. The aims of this study were to determine the diversity of the staphylococcal cassette chromosome mec (SCCmec) elements among MRCNS isolates from pigs and to examine the species distribution and antibiotic resistance of these isolates. Sixteen isolates of pig MRCNS were recovered and identified at a species level and subsequently confirmed by PCR detection of staphylococcal 16S rRNA, nuc and mecA genes. These isolates consisted of six staphylococcal species. The most predominate species was S. saprophyticus (9 isolates), followed by S. cohnii (2 isolates) and S. haemolyticus (2 isolates). All isolates were resistant to at least three classes of 10 tested antibiotics – penicillin, erythromycin and clindamycin, but susceptible to vancomycin, gentamicin and tigecycline. However, some isolates were also resistant to other non-beta-lactam antibiotics. The most prevalent SCCmec type was type IX, which was detected in six isolates (37.5%). This is the first report of SCCmec type IX in MRCNS in pigs in Thailand. SCCmec type V was also detected in three isolates (18.8%). In addition, seven isolates (43.8%) were non-typeable and possibly possess a novel type of SCCmec. Therefore, MRCNS in pigs might be a potential source of diverse SCCmec elements that result to beta-lactam resistance among other staphylococci, especially S. aureus, an important human pathogen.  Bull Chiang Mai Assoc Med Sci