Genetic characterization of antimicrobial resistance in coagulase-negative staphylococci from bovine mastitis milk

Abstract

Coagulase-negative staphylococci (CNS; n = 417) were isolated from bovine milk and identified by matrix-assisted laser desorption/ionization time-offlight mass spectrometry. Nineteen different species were identified, and Staphylococcus xylosus, Staphylococcus chromogenes, Staphylococcus haemolyticus, and Staphylococcus sciuri were the most prevalent species. Resistance to oxacillin (47.0% of the isolates), fusidic acid (33.8%), tiamulin (31.9%), penicillin (23.3%), tetracycline (15.8%), streptomycin (9.6%), erythromycin (7.0%), sulfonamides (5%), trimethoprim (4.3%), clindamycin (3.4%), kanamycin (2.4%), and gentamicin (2.4%) was detected. Resistance to oxacillin was attributed to the mecA gene in 9.7% of the oxacillin-resistant isolates. The remaining oxacillin-resistant CNS did not contain the mecC gene or mecA1 promoter mutations. The mecA gene was detected in Staphylococcus fleurettii, Staphylococcus epidermidis, Staph. haemolyticus, and Staph. xylosus. Resistance to tetracycline was attributed to the presence of tet(K) and tet(L), penicillin resistance to blaZ, streptomycin resistance to str and ant(6)-Ia, and erythromycin resistance to erm(C), erm(B), and msr. Resistance to tiamulin and fusidic acid could not be attributed to an acquired resistance gene. In total, 15.1% of the CNS isolates were multidrug resistant (i.e., resistant to 2 or more antimicrobials). The remaining CNS isolates were susceptible to antimicrobials commonly used in mastitis treatment. Methicillin-resistant CNS isolates were diverse, as determined by mecA gene sequence analysis, staphylococcal cassette chromosome mec typing, and pulsed-field gel electrophoresis. Arginine catabolic mobile element types 1 and 3 were detected in both methicillin-resistant and methicillin-susceptible Staph. epidermidis and were associated with sequence types ST59 and ST111. Because this study revealed the presence of multidrugresistant CNS in a heterogeneous CNS population, we recommend antibiogram analysis of CNS in persistent infections before treatment with antimicrobials.

Quarter- and cow-level risk factors for intramammary infection with coagulase-negative staphylococci species in Swiss dairy cows

“…Variance components of all final models are presented in Table 8 Frey et al, 2013). It must be noted that the Staph.…”

“…Ten microliters of milk sediment was streaked on chromogenic agar plates selective for staphylococci (SaSelect, Bio-Rad, Marnes-la-Coquette, France) and incubated at 37°C for 48 h. Growth of staphylococci from milk on this selective agar was first validated with a collection of 19 different Staphylococcus species previously isolated from mastitis milk (Frey et al, 2013). Staphylococci were discriminated from incidentally growing non-staphylococci-like Corynebacterium spp., Bacillus spp., and Aerococcus spp.…”

Isolation of <i>Staphylococcus sciuri</i> from horse skin infection

“…Discussion S. sciuri is mostly recovered from skin and mucous membrane of animals and has long been considered as a non-pathogenic commensal bacterium (Adegoke, 1986). During the last decade of years, it has been associated with several cases of bovine mastitis (Lüthje and Schwarz, 2006;Nam et al, 2010;Frey et al, 2013), as well as from goats suffering from peste des petites ruminants (PPR) (Ugochukwu and Agwu, 1991), from cases of canine dermatitis (Hauschild and Wójcik, 2007;Hauschild et al, 2010), and from several outbreaks of fatal exudative epidermitis in piglets (Chen et al, 2007;Nemeghaire et al, 2014c). The recurrent manifestation of skin lesions monitored in the present case, initially suggested a permanent colonization of the horse with S. sciuri.…”

“…This group includes S. sciuri (with three subspecies), S. lentus, S. vitulinus, S. fleurettii and S. stepanovicii (Becker et al, 2014a), which are in general considered as commensal animal-associated species (Kloos et al, 1976). S. sciuri possesses a certain pathogenic potential and is able to induce infections in both, animals (Frey et al, 2013;Dos Santos et al, 2015) and humans (Stepanovic et al, 2003). Some isolates of the S. sciuri group are known to carry different homologues of the methicillin resistance genes mecA, B and C and display methicillin/oxacillin resistance (Becker et al, 2014a,b;Harrison et al, 2014).…”

New Macrolide-Lincosamide-Streptogramin B Resistance Gene erm (48) on the Novel Plasmid pJW2311 in Staphylococcus xylosus

“…taphylococcus xylosus is an important cause of subclinical bovine mastitis and is therefore in frequent contact with intramammary antibiotics used for mastitis treatment, such as macrolides and lincosamides (1). S. xylosus strain JW2311 was isolated from bovine mastitis milk in Switzerland in 2010.…”