Short communication: Occurrence of methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci in dairy goat herds in Ohio, United States

Abstract

In light of the scarcity of information about the occurrence and epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (MRCNS) in small ruminants in general, and particularly dairy goats, we launched this limited-scope study. The findings reported here show the detection of MRSA and MRCNS in goat milk and teat skin samples from dairy goat herds in the state of Ohio. A total of 120 milk samples and 120 teat-swab samples were collected from 5 farms. After conventional isolation and phenotypic characterization of the staphylococci colonies, bacterial isolates were tested by PCR assay targeting the genes nuc to identify Staphylococcus aureus and mecA to detect MRSA and MRCNS. The clonal complexes of MRSA isolates was also determined by multiloccus sequence typing. Fifteen (6.2%) positive S. aureus samples were found in this study: 9 from milk and 6 from teat skin samples. Four (2%) MRSA isolates were detected and, using multiloccus sequence typing genotyping, these were designated to clonal complexes CC133 (n = 2; milk samples) and CC5 (n = 2; teat skin). Three (1.25%) coagulase-negative staphylococci isolates from the teat skin also harbored the mecA gene. Although, the MRSA isolated from milk samples is not a typical human-associated lineage, the CC5 clone isolated from teat skin is a common and widespread clonal complex associated with humans, suggesting that this extramammary niche could be a relevant reservoir of methicillin-resistant staphylococci. Furthermore, the fact that 75% of MRSA were recovered from 1 farm showing poor hygiene practices strengthens the hypothesis that good hygiene practices could be useful to prevent persistence and spread of MRSA at a farm level.

β-lactam resistance in coagulase-negative Staphylococcus isolated from subclinical goat mastites

“…urealyticum). These results are similar to those obtained by Moura et al (2018), who reported a frequency of 1.25% for the mecA gene in CoNS isolated from goat mastitis. Contrarily, Cantekin et al (2019), Nobrega et al (2018, Bhargava & Zang (2012), and Klimiene et al (2016) found rates of 6.6, 17, 60, and 67.8% in CoNS isolated from different animal origins.…”

No Detection of Methicillin-Resistant Staphylococcus aureus in Dairy Goats

“…In two studies from Italy, the bulk milk prevalence was 0.6 and 2%, respectively [20,21]. On an individual goat level, the MRSA prevalence has been described to range from 2% in the US and Saudi Arabia to 8% in Austria, 16% in Tenerife, Spain, and 23% in Nigeria [2,[22][23][24][25]. However, a direct comparison of the occurrence between studies should be done with care since different methods for sampling and detection are used in different studies.…”

Safety Issues Regarding the Detection of Antibiotics Residues, Microbial Indicators and Somatic Cell Counts in Ewes’ and Goats’ Milk Reared in Two Different Farming Systems

“…-Detection of Staphylococcus sp. [31][32][33]: 1 mL of milk samples was enriched in 9 mL of Mueller-Hinton broth supplemented with 6.5% NaCl (Oxoid Ltd., Basingstoke, UK). Incubation at 37 • C for 20 h followed and 1 mL was enriched in 9 mL of Tryptone Soya broth with 10% NaCl and 1% sodium pyruvate (HiMedia Labs, Einhausen, Germany).…”