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OBJECTIVE To survey the distribution of class Ⅰ integron in extended-spectrum beta-lactamases(ESBLs)-producing Escherichia coli and Klebsiella pneumoniae and its contribution in horizontal transfer of ESBLs genes.METHODS The presence of class Ⅰ integron among 230 ESBLs-producers and 197 non-ESBLs-producers of E.coli and K.pneumoniae were detected by PCR.The correlation and co-transfer between integron and genes coding for SHV,CTX and TEM were studied. RESULTS One hundred and thirty-seven(59.6%) isolates were positive for intⅠ gene among ESBLs-producers,contrasted to 48(24.4%) in non-ESBLs-producers(P
ABSTRACT
OBJECTIVE To determine the drug resistance phenotype and genotype of plasmid-mediated AmpC ?-lactamase in Klebsiella pneumoniae isolated from Harbin.METHODS Isolates of K.pneumoniae with an inhibition ring to cefoxitin of ≤18 mm diameter were used.Antimicrobial susceptibilities were determined by disc diffusion method.AmpC genes were detected by PCR with six pairs of primers.RESULTS Sixty-three isolates had an inhibition ring to cefoxitin of ≤18 mm diameter and 26(11.3%)were detected to be AmpC-producing in a total of 231 clinical isolates of K.pneumoniae.Seventy-six percent,70.2%,53.8%,50.5%,57.7%,38.5% and 7.7% of AmpC-producers were resistant to cefoxitin,cefotaxime,ceftazidime,amoxicillin/clavulanic cid,ciprofloxacin,amikacin and imipenem,respectively.ACT,DHA and CIT types of AmpC beta-lactamase were detected in 13,8 and 5 isolates,respectively.No ACC,MOX and FOX were detected.CONCLUSIONS The AmpC ?-lactamase in Harbin is mainly in the types of ACT,DHA and CIT.AmpC-producing K.pneumoniae shows decreased susceptibilities to cefoxitin and third generation cephalosporins.