Short communication: Antimicrobial resistance and virulence characterization of methicillin-resistant staphylococci isolates from bovine mastitis cases in Portugal.
Methicillin-resistant staphylococci (MRS) have already been reported as mastitis agents. Such bacterial species are a public health concern, and the characterization of their antimicrobial resistance and virulence profile is important to better control their dissemination. The present work evaluated the distribution of methicillin-resistance among 204 staphylococci from clinical (n=50) and subclinical (n=154) bovine mastitis. The presence ofthe mecA gene was determined by PCR. Phenotypic expression of coagulase, DNase, lipase, gelatinase, hemolytic enzymes, and biofilm production was evaluated. The presence of biofilm-related genes, icaA, icaD, and bap, was also determined. Antimicrobial resistance patterns for aminoglycosides, lincosamides, macrolides, fluoroquinolones, sulphonamides, tetracyclines, and fusidic acid were determined. Nineteen (9.3%) isolates were identified as MRS, and the presence of mecA in these isolates was confirmed by PCR. Virulence factors evaluation revealed that gelatinase was the most frequently detected (94.7%), followed by hemolysins (73.7%) and lipase (68.4%); 84.2% of the MRS isolates produced biofilm and icaA and icaD were detected in almost half of the MRS isolates (52.6%), but all were bap-negative. Resistance against other antimicrobial agents ranged from 0 (fusidic acid, ciprofloxacin, norfloxacin, enrofloxacin) to 100% (nalidixic acid). Resistance to nalidixic acid and nalidixic acid-tetracycline were the most common antimicrobial resistance profiles (31.6%). This study confirms that despite the low prevalence of MRS, isolates frequently express other virulence traits, especially biofilm, that may represent a serious challenge to clinicians.
Immunology and Microbiology Laboratory, Interdisciplinary Centre of Research in Animal Health (CIISA)/Faculdade de Medicina Veterinária da Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
R
R
Seixas
Immunology and Microbiology Laboratory, Interdisciplinary Centre of Research in Animal Health (CIISA)/Faculdade de Medicina Veterinária da Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
J P
JP
Santos
Immunology and Microbiology Laboratory, Interdisciplinary Centre of Research in Animal Health (CIISA)/Faculdade de Medicina Veterinária da Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
R
R
Bexiga
Immunology and Microbiology Laboratory, Interdisciplinary Centre of Research in Animal Health (CIISA)/Faculdade de Medicina Veterinária da Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
C L
CL
Vilela
Immunology and Microbiology Laboratory, Interdisciplinary Centre of Research in Animal Health (CIISA)/Faculdade de Medicina Veterinária da Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal. Electronic address: moliveira@fmv.utl.pt.
M
M
Oliveira
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D002417:Cattle; D003030:Coagulase / Q000235:genetics / Q000378:metabolism; D003851:Deoxyribonucleases / Q000235:genetics / Q000378:metabolism; D005260:Female; D018093:Gelatinases / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D008049:Lipase / Q000235:genetics / Q000378:metabolism; D008414:Mastitis, Bovine / Q000188:drug therapy* / Q000382:microbiology*; D016106:Methicillin Resistance / Q000235:genetics*; D011174:Portugal; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013210:Staphylococcus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics
D000900:Anti-Bacterial Agents; D003030:Coagulase; D037521:Virulence Factors; D003851:Deoxyribonucleases; D008049:Lipase; D018093:Gelatinases
biofilm; bovine mastitis; methicillin resistance; staphylococci