Epidemiological And Molecular Biological Study On Klebsiella Pneumoniae And Escherichia Coli Producing Extended-spectrum β-lactamases In Bengbu, AnHui Province

BackgroundSoon after introducing the clinical use of extended-spectrum cephalosporins, such as cefetaxime,ceftriaxone,aztreonam and ceftazidime, SHV2-type-extended-spectrum β -lactamases(ESBLs) were firstly isolated from Enterobacteriaceae in Germany in 1983. Then, reports about new ESBLs spread around the world.extended spectrum beta-lactamases were plasmid-mediated ,which made bacteria resist to many beta-lactams. ESBLs were produced by Gram-negative bacteria, and the resistance of ESBLs-producing strains has currently become one of the most important nosocomial resistance problems in hospitals around the world.ESBLs have spread around the world from they were reported .The partly reason is the fact that we lack dependable test method.After third generation cephalosporin treatment failed,the people began to be aware of ESBLs existence. In ordor to control its epidemic ,early detection of ESBLs is very important, and genetype diversity everywhere lead to distinction of resistance and detecting substrates. We studied on the best detective substrates and drug-resistance of ESBLs-producing K.pneumoniae and E.coli isolates in Bengbu ,Anhui Province,So that we could prevent regional prevalence of ESBLs producers and guide clinical therapy in order to avoid delaying therapy and wasting drugs.In view of lacking wide-ranging investigation about the prevalence of ESBLs in Anhui, we studied the resistance and resistant genotypes of ESBLs-producing K.pneumoniae and E.coli isolates in Bengbu ,Anhui ProvinceObjectiveTo study the best detective substrate of ESBLs-producing K.pneumoniae and E.coli isolates from Bengbu ,Anhui Province.To investigate epidemiological data and resistance of ESBLs producers in Bengbu,Anhui Province from 2003 to 2004.To study resistant genotypes of ESBLs producers isolated from from Bengbu ,Anhui Province from 2003 to 2004.Materials and Methods300 clinical isolates of K.pneumoniae and E.coli were collected from different hospitals in Bengbu. and identified using MicroScan WalkAway-40 system. Their resistance to 18 antimicrobial agents were also tested by the system automaticly manufacturers' criteria, ESBls producers were screened by ESBLs initial screening test and phenotype comfirmatory test in accordance to the guidelines of NCCLS in 1999,respectively.Eight pairs of primers were designed in accordance to the basic sequences of blarEM, blasuv, blacix ,6/ooxa in the GenBank,respectively.PCR was performed with the Eight pairs primers respectively.ResultsCTX was the best detective substrates of ESBLs-producing K.pneumoniae and E.coli isolates in Bengbu. and CAZ resistance as a single marker for presence of ESBLs may be unreliable. The incidence of ESBLs of K.pneumoniae and E.coli were 50.0% and 57.1% respectively.Compared with the resistance rates of non-ESBLs producing strains, ESBLs producers were more resistant to ceftazidime, aztreonam, cefoxitin, and ciprofloxacin. but all ESBLs producers were susceptible to imipenem. PCR results...