Mariela E Srednik1, Marie Archambault2, Mario Jacques2, Elida R Gentilini3. 1. Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Microbiología, Av. Chorroarín 280, C1427CWO Buenos Aires, Argentina. 2. Université de Montréal, Faculté de Médecine Vétérinaire, 3200 rue Sicotte, Saint-Hyacinthe, Québec J2S 7C6, Canada; Regroupement de recherche pour un lait de qualité optimale (Op+Lait), Canada; Canadian Bovine Mastitis and Milk Quality Research Network, Canada. 3. Universidad de Buenos Aires, Facultad de Ciencias Veterinarias, Cátedra de Microbiología, Av. Chorroarín 280, C1427CWO Buenos Aires, Argentina. Electronic address: egenti@fvet.uba.ar.
Abstract
INTRODUCTION: Bovine mastitis causes important economic losses in the dairy industry. Coagulase-negative staphylococci (CNS) are a group of bacteria commonly isolated from bovine mastitis and can display resistance to a wide range of antimicrobial agents. OBJECTIVES: The objective of this study was to determine staphylococcal resistance towards β-lactam, macrolide and lincosamide antimicrobials in quarters previously treated with third-generation cephalosporin and after lincosamide intramammary therapy. METHODS: Sick quarters of eighteen cows from Villaguay, Entre Ríos (Argentina) with clinical mastitis were studied. All staphylococcal isolates were tested by disk diffusion for their antimicrobial susceptibilities. Cefoxitin resistance was investigated by PCR and sequencing for both the mecA and mecC genes. RESULTS: Resistances to penicillin, oxacillin and cefoxitin were observed, whereas no resistance to macrolide and lincosamide was detected. A cefoxitin-resistant Staphylococcus saprophyticus was found to be mecA-negative but mecC-positive. CONCLUSIONS: This study reports for the first time the mecC gene from a CNS in bovine mastitis in South America. Because CNS may act as reservoirs of antimicrobial resistance genes, they can be seen as a potential public health threat with respect to antimicrobial resistance and the development of multiple resistance. Also, the emergence of methicillin-resistant phenotypes will limit therapeutic options.
INTRODUCTION:Bovinemastitis causes important economic losses in the dairy industry. Coagulase-negative staphylococci (CNS) are a group of bacteria commonly isolated from bovinemastitis and can display resistance to a wide range of antimicrobial agents. OBJECTIVES: The objective of this study was to determine staphylococcal resistance towards β-lactam, macrolide and lincosamide antimicrobials in quarters previously treated with third-generation cephalosporin and after lincosamide intramammary therapy. METHODS: Sick quarters of eighteen cows from Villaguay, Entre Ríos (Argentina) with clinical mastitis were studied. All staphylococcal isolates were tested by disk diffusion for their antimicrobial susceptibilities. Cefoxitin resistance was investigated by PCR and sequencing for both the mecA and mecC genes. RESULTS: Resistances to penicillin, oxacillin and cefoxitin were observed, whereas no resistance to macrolide and lincosamide was detected. A cefoxitin-resistant Staphylococcus saprophyticus was found to be mecA-negative but mecC-positive. CONCLUSIONS: This study reports for the first time the mecC gene from a CNS in bovinemastitis in South America. Because CNS may act as reservoirs of antimicrobial resistance genes, they can be seen as a potential public health threat with respect to antimicrobial resistance and the development of multiple resistance. Also, the emergence of methicillin-resistant phenotypes will limit therapeutic options.
Authors: A C MacFadyen; E M Harrison; M J Ellington; J Parkhill; M A Holmes; G K Paterson Journal: J Antimicrob Chemother Date: 2018-12-01 Impact factor: 5.790
Authors: Diego B Nobrega; Sohail Naushad; S Ali Naqvi; Larissa A Z Condas; Vineet Saini; John P Kastelic; Christopher Luby; Jeroen De Buck; Herman W Barkema Journal: Front Microbiol Date: 2018-02-16 Impact factor: 5.640