Investigation of methicillin resistance and Panton-Valentine leukocidin in Staphylococci isolated from bovine mastitis

Background: Mastitis, which is inflammation of the mammary gland, is among the most important diseases in dairy herds resulting in reductions of milk yield and milk quality. Although several groups of microorganisms have been reported as etiological agents of mastitis, Staphylococci are the most frequently isolated bacteria from bovine mastitic milk samples. The aim of this study was to isolate the Staphylococcus species from bovine mastitis, investigate the mecA ve pvl genes in isolated species by PCR and determine the antibiotic resistance of methicillin resistant strains to some antibiotics commonly used in veterinary field. Materials, Methods & Results: In the present study, 972 half-udder milk samples (n = 757 CMT positive, n = 215 CMT negative) were used from 251 lactating cows from 34 different enterprises located center town and villages of Õdemi, zmir. Ten microliters of each milk sample was inoculated onto Columbia blood agar, containing 7% of sheep blood and incubated under aerobic conditions for 24-48 h at 37C. The certain identification of Staphylococcus isolates was achieved using Crystal Identification Systems Gram-Positive ID kit. Bacterial DNAs were extracted from all strains using boiling method and strains were screened for the presence of 16S rDNA, mecA and pvl genes by PCR. The antimicrobial resistance of MRS species was determined by using disc [...](AU)

Investigation of methicillin resistance and Panton-Valentine leukocidin in Staphylococci isolated from bovine mastitis

Background: Mastitis, which is inflammation of the mammary gland, is among the most important diseases in dairy herds resulting in reductions of milk yield and milk quality. Although several groups of microorganisms have been reported as etiological agents of mastitis, Staphylococci are the most frequently isolated bacteria from bovine mastitic milk samples. The aim of this study was to isolate the Staphylococcus species from bovine mastitis, investigate the mecA ve pvl genes in isolated species by PCR and determine the antibiotic resistance of methicillin resistant strains to some antibiotics commonly used in veterinary field. Materials, Methods & Results: In the present study, 972 half-udder milk samples (n = 757 CMT positive, n = 215 CMT negative) were used from 251 lactating cows from 34 different enterprises located center town and villages of Õdemi, zmir. Ten microliters of each milk sample was inoculated onto Columbia blood agar, containing 7% of sheep blood and incubated under aerobic conditions for 24-48 h at 37C. The certain identification of Staphylococcus isolates was achieved using Crystal Identification Systems Gram-Positive ID kit. Bacterial DNAs were extracted from all strains using boiling method and strains were screened for the presence of 16S rDNA, mecA and pvl genes by PCR. The antimicrobial resistance of MRS species was determined by using disc [...]

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA): molecular background, virulence, and relevance for public health

Staphylococcus aureus and coagulase-negative Staphylococcus (CoNS) are frequently found in nosocomial environments as the main pathogen in several infections. In 1961, reports of nosocomial S. aureus resistant to methicillin, the drug of choice against penicillin-resistant strains, required new alternatives and vancomycin started being used to treat infections caused by methicillin-resistant S. aureus (MRSA). Community-acquired methicillin-resistant S. aureus (CA-MRSA) was first reported in 1990 affecting patients without risk factors for infection with MRSA of hospital origin. MRSA of community origin harbor the genes responsible for the synthesis of Panton-Valentine leukocidin (PVL), a toxin associated with skin and soft tissue infections and that carries the staphylococcal cassette chromosome mec (SCCmec) type IV. CA-MRSA emergence has caused great impact on the worldwide medical community since the presence of this pathogen in patients without risk factors represents a high risk to public health.(AU)