Study Of ESBLs Genotype And Antimicrobial Resistance Of ESBLs-producing Escherichia Coli From Clinical Samples

ObjectivesEscherichia coli remains a common pathogen in nosoeomia infection. With thewide use of third generation cephalosporins, infection by ESBLs-producing E. coli isincreasing, ESBLs are plasmid-mediated production and easy to lead outbreak, andtransfer with in same species or even different species. The predominant ESBLsgenotype may vary depending on different antibiotics usage in different countries andregions. The spread of ESBLs and their multiple resistance to antibiotic caused greatdifficulties, timely and accurate detection of ESBLs is very important to prevent ESBLsepidemic, infection control. Accordingly, the present study takes NCCLS qualifiedmethodology to investigate ESBLs prevalence its gene type and the antimicrobialprocedure of ESBLs-producing E. eoli. It may provide some information dealing withtreatment, and prevention of ESBL-producing bacterial infections.MethodWe collect a total of 120 unduplicated strains from January 2004 to December2005, according to the National Committee for Clinical Laboratory Standardization(NCCLS) which recommended ESBLs phenotypic cenfirmiry test screenedESBLs-producing E.coli. Extracted plasmid DNA of the ESBLs-producing strainsusing specific PCR primers to amplify TEM type,SHV type,CTX-M-1,CTX-M-9groups, All the positive PCR products DNA were sequenced.ResultsThe results showed that ESBLs-producing E. coli manifested high resistance rate, of which ampicllin 100%, first and the second generation cephalosporins (cefazolin,cefuroxime) more than 90%, the ceftriaxone 80%, cefotaxime 76.7%, tetracycline90%, levofloxacin 86.6%, ciprofloxacin 85%, Trimethoprim-sulfamethoxazole 83.3%,Piperacillin/tazobactam 3.3%, Cefoperazone/sulbactam sodium 16.7%. Innon-ESBLs-producing E. coli ampicillin resistance is up to 88%, tetracycline 80%,imipenem resistance.was not found in ESBLs-producing strains.This study shows 45 strains were 75% ESBLs-producing E. coli is accout forCTX-M-14 were 82.2%(37/45),CTX-M-9 were 4.4%(2/45),CTX-M-15 were2.2%(1/45),CTX-M-22 were 4.4% (2/45),CTX-M-24 were 2.2%(1/45),CTX-M-27were 2.2%(1/45).In one isolate suggests co-existence of CTX-M-14 and TEM-1genotypes, about 2%.DiscussionESBLs-producing E. coli is resistant to multiple antibiotics, but we did not findimipenem resistant strains, we recommend it in treatment of severe infection.CTX-M type,most of which were CTX-M-14 type, is the most common ESBLsthat produced by E. coli isolatesin.The rational use of antibiotics, especially the third generations of cephalosporins,monitoring bacterial resistance in high-risk areas of hospitals, targeed of treatment mayhelp in reducing antibiotics resistance.ConclusionESBLs-producing E. coli leads to antibiotics resistance even lable, but stillsensitive to imipenem.The most common type of ESBLs-production by E. coli isCTX-M, mainly CTX-M-14 in The First Affiliated Hospital of China MedicalUniversity.