coagulase-negative staphylococci (cons) are often associated with bovine mastitis and may be resistant to antimicrobial therapy. the aim of the current study was to investigate the presence of blaz (responsible for penicillin resistance) and meca (responsible for methicillin resistance) genes among 108 cons belonging to 9 different species isolated from bovine mastitis in seven dairy herds (h1-...

In contrast to most Staphylococcus aureus isolates in which the gene for staphylococcal beta-lactamase (blaZ) is plasmid borne, isolates typeable by group II bacteriophages frequently carry blaZ on the chromosome. Furthermore, the chromosomal gene encodes the type B variant of staphylococcal beta-lactamase for which the nucleotide and deduced amino acid sequences have not yet been reported. To ...

INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) is caused by the production of low-affinity penicillin-binding protein 2a and β-lactamases, which are encoded by mecA and blaZ, respectively. Expressions of the two key genes are mutually regulated by MecI and BlaI. The aim of this study was to design specific anti-mecR1 and anti-blaR1 deoxyribozymes and identify the restoration of...

Altered production of penicillin-binding protein 2a (PBP 2a) may affect the phenotypic expression of resistance in methicillin-resistant Staphylococcus aureus (MRSA). COL, an MRSA strain that constitutively produces PBP 2a, was transformed with a recombinant plasmid containing the two beta-lactamase regulatory genes, blaI and blaR1, with either the beta-lactamase gene, blaZ, or a truncated blaZ...

background staphylococcus aureus is a significant pathogen that can colonize the nares of different animals, causing a wide range of infections in various hosts. objectives we intended to determine the prevalence of s. aureus in the nasal cavity of healthy ruminants and also to investigate the presence of antibiotic resistance genes. materials and methods in the present study, healthy cattle (n...

The aim of this study was to investigate the presence of virulence genes in 46 coagulase-negative staphylococci (CNS) strains isolated from 46 udder quarters of 46 cows with subclinical mastitis. The isolates were examined phenotypically (cultural features, Gram stain, catalase, coagulase, API tests) and genotypically for: icaA, icaAB, icaD, atlE, bhp, agrA, sarA, mecA, and blaZ genes. These is...

Using blaZ PCR as the "gold standard," the sensitivities of CLSI penicillin zone edge and nitrocefin-based tests for β-lactamase production in Staphylococcus aureus were 64.5% and 35.5%, respectively, with specificity of 99.8% for both methods. In 2013, 13.5% of 3,083 S. aureus isolates from 31 U.S. centers were penicillin susceptible.

OBJECTIVES The mec and bla systems, among other genetic factors, are critical in regulating the expression of methicillin resistance in Staphylococcus aureus. We examined by WGS a naturally occurring oxacillin-susceptible mecA-positive S. aureus isolate to identify the mechanism conferring oxacillin susceptibility. METHODS The mecA-positive oxacillin-susceptible S. aureus isolate GR2 (penicil...

ABSTRACT Bovine clinical mastitis caused by Staphylococcus spp. is a serious and widespread disease in the world of dairy farming. Antimicrobial therapy fundamental importance prevention treatment infectious mastitis, but indiscriminate use antimicrobials acts as determining factor for spread disease. The present study evaluated resistance profiles 57 isolated from bovine to beta-lactams gentam...