Antimicrobial resistance and genotypes of staphylococci from bovine milk and the cowshed environment

Abstract

Investigation of antimicrobial resistance and genetic relatedness of staphylococci from milk of cows with mastitis and cowshed environment was the aim of this study. Antimicrobial resistance against 14 antimicrobials were determined by using a disc diffusion method. Genetic similarity between the most frequently isolated species was analysed by PFGE (pulsed-field gel electrophoresis). Haemolytic activity, DNase, protease and esterase production was also investigated. Coagulase-negative Staphylococcus species were isolated from 30.8% of milk samples from cows with mastitis. The most frequently isolated species was Staphylococcus xylosus and yield of these organisms was significantly associated with milk of mastitis cows. S. epidermidis was a predominant penicillin-resistant species. High frequency of resistance to lincomycin was observed among isolates of S. sciuri (54.2%) and S. xylosus (25.9%) from cows with mastitis. PFGE (pulsed-field gel electrophoresis) analysis of 29 Staphylococcus aureus isolates showed the presence of 17 PFGE pulsotypes. Isolates of S. sciuri (n=36) had unique PFGE patterns. Some S. xylosus isolates from milk and milker's hands had the same PFGE pulsotypes, and this observation could indicate that dairyman may be a potential source of the infection. The pulsotype of each of the remaining isolates of S. xylosus suggested that they might have come from common environmental sources; however, these isolates differed in antibiotic resistance pattern or virulence traits. Therefore, knowledge about antibiotic sensitivity pattern and virulence factors of a CNS isolate, besides its genotype, may be informative in tracking the source of the infection.

Detection and characterization of methicillin-resistant and susceptible coagulase-negative staphylococci in milk from cows with clinical mastitis in Tunisia.

“…On the other hand, the MS-CNS isolates showed susceptibility to the tested antimicrobials, with some exceptions due to the presence of erm(B), erm(C), erm(T), msr(A), mph(C) and tet(K) genes. It's important to note, that tetracycline resistance was encoded only by the tet(K) gene in both groups, being this resistance gene very frequent in staphylococci species [29]. According to our study, the…”

Virulence gene profiles inStaphylococcus aureusisolated from cows with subclinical mastitis in eastern Poland

“…In Poland comprehensive data concerning genes encoding adhesins, proteases and enterotoxins in Staph. aureus from mastitis cases are limited (Kot et al 2012a; Jagielski et al 2014). In our study, we investigated the presence of 30 important virulence genes encoding adhesins, proteases and superantigenic toxins.…”

Seasonal Distribution, Antimicrobial Activity, and Risk Factors Associated with the Incidence of Staphylococcus Species in Bovine Milk from a Dairy Farm in Eastern Cape, South Africa

“…They cause both clinical and subclinical mastitis in cattle (Supré et al, 2011), though clinical mastitis caused by CNS species may be placid in some cases . Common CNS species isolated from bovine mastitis include Staphylococcus chromogenes, Staphylococcus xylosus, Staphylococcus epidermidis, Staphylococcus sciuri, and Staphylococcus haemolyticus (Kot et al, 2012;Tenhagen et al, 2006). Other CNS species (e.g., Staphylococcus saprophyticus, Staphylococcus hominis, Staphylococcus warneri, Staphylococcus capitis) causing bovine mastitis have been well documented (Sampimon, Lam, Mevius, Schukken, & Zadoks, 2011).…”