The major aim of this study was to investigate the distribution of genes that encode multidrug efflux pumps in Enterococci spp. isolates from bovine milk samples and antibiotic resistance patterns of these strains. of different species of Enterococci, eme(A) was also detected in four strains of E. faecium, seven strains of E. avium, four strains of E. durans and two strains of E. raffinosus. efr(A) was also detected in two strains of E. faecium and two strains of E. durans and efr(B) was also detected in four strains of E. faecium, five strains of E. avium and four strains of E. durans. This means the possibility of co-transfer of resistance genes between Enterococci species in natural environment. These results are the first report describing the presence of same multidrug efflux pumps in different species of Enterococci in Korea.
-This study was investigated to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) isolated from raw milk samples and to further study on the molecular characteristics of the MRSA isolates. Using Staphylococcus Medium 110, Staphylococcus spp. were isolated from raw milk samples and further identification was carried by Vitek2 system. Minimum inhibitory concentrations (MICs) of antibiotics were conducted by serial dilution method according to the Clinical Laboratory Standards Institute (CLSI) guideline. For the detection of resistance genes and molecular characterization, PCR reaction was performed by gene specific primers and followed by DNA sequencing. Of the 698 milk samples, 94 Staphylococcus aureus (S. aureus) were identified (94 S. aureus /286 Staphylococcus spp.). Of the 94 S. aureus, seven isolates have mecA, a methicillin resistant gene. mecA positive seven isolates were then characterized by staphylococcal cassette chromosome mec (SCCmec) typing, and Panton-Valentine Leukocidin (pvl) gene using PCR. All of mecA positive isolates were resistant to ampicillin and oxacillin, but sensitive to teicoplanin, vancomycin and ciprofloxacin. One of seven isolates was SCCmec type II and six isolates were type IV and all seven isolates were pvl gene negative.
The aim of this study was to investigate the prevalence of quinolone resistant E. coli from raw bulk milk and to characterize the resistance determinants. In this study, the gyrA, gyrB, parC, and parE quinolone resistance determining regions (QRDR) were sequenced from quinolone resistant E. coli isolates. Also, the presence of plasmid-mediated quinolone resistance (PMQR) and the expression of efflux pump genes based on quantitative real-time PCR (qRT-PCR) were investigated. Of the 487 coliform bacteria, 9 strains showed nalidixic acid resistance, and 6 of the 9 nalidixic acid resistant isolates were also ciprofloxacin resistant. These 9 strains had a single mutation at codon 83 (S83L) in gyrA, 2 of them had double mutations at codon 83 and 87 (S83L and D87N) in gyrA and 3 of the 9 isolates had single mutations at codon 80 (S80I) in parC. None of the 9 isolates harbored PMQR determinants. Compared with wild-type E. coli ATCC 25922, an over-expression of the acrB gene (2.15-5.74 fold), encoding the pump component of the AcrAB-TolC efflux pump was observed in 4 of 6 ciprofloxacin resistant isolates. This study identified the quinolone resistance mechanism of E. coli isolated from raw milk samples in Gyeonggi-do. (Poirel et al., 2013). 플라스미드에 위치 한 quinolone 내성에 관여하는 유전자로는 qnr 그룹에 속하는 qnrA, qnrB, qnrS 등과 항생제의 변형에 관여하는 aac(6')-lb-cr 및 active efflux pump 유전자인 qepA 등이 알려져 있다 (Strahilevitz et al., 2009;Rodríguez-Martínez et al., 2011). 대장균군(coli form bacteria) 세균은 포유동물의 대장에 상존하는 정상 세균총 이며 환경 중에도 어디에서나 존재 할 수 있으며 대부분은 병원 성이 없으나 일부는 설사, 급성 위장염 등을 일으키며 동물에서 도 장 질환을 유발할 뿐 아니라 소의 유방염을 유발하는 원인균 으로 주목 받고 있다 (Wenz et al., 2001). 환자에서 분리된 임상
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