Resistance of Clinical Isolated Gram-negative Bacilli to ?-Lactam Antibiotics / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To study the resistant characteristics and the resistant mechanisms of Gram-negative bacilli(G-) to ?-lactam antibiotics in the local nosocomial infections.METHODS The effects of efflux pump inhibitor on MICs were determined.Phenotypes and isoelectric points of ?-lactamases(Bla) were determined.Bla Genes were amplified and sequenced.RESULTS Of all tested isolates,the resistant rates to the most antibiotics were high.Besides 10.5% isolates with the efflux pumps,all tested isolates produced Bla,among which extended spectrum ?-lactamases(ESBLs),cephalosporin ?-lactamase(AmpC Bla) and metallo-?-lactamase were responsible for 42.1%,17.5% and 7.0% isolates,respectively.The complete nucleotide sequences of the ampC genes in 8 Enterobacter cloacae isolates had very high homology with the ampC gene in E.cloacae ECLC074.CONCLUSIONS The production of Bla is the main resistant mechanism of G-to ?-lactam antibiotics.ESBLs are the most frequent Bla.All of the ampC genes of AmpC Bla-producing E.cloacae originate from the ampC gene in E.cloacae ECLC074.Imipenen is the best choice for the treatment of the infections caused by multidrug resistant G-.Piperacillin/tazobactam and cefoperazone/sulbactam can be used to treat the infections caused by drug-resistant non-fermentative bacilli.Amikacin is effective to treat the infections caused by AmpC Bla-producing E.cloacae.