The Investigation Of Distribution Of Bacterial In Urinary Tract Infection And The Study On Drug-resistance And Genotype Of Escherichia Coli

Background Since 1983,the first extended spectrum beta-lactamase(ESBLs) was reported in Germany, the prevalence of ESBLs was reported all around the world. And some new ESBLs was found continuely in many place. No more than 20 years,the kinds of ESBLs have exceeded 150.Extended spectrum beta-lactamases were plasmid-mediated, which made bacteria resist to many beta-lactams. Now ESBLs were mostly divided into categories of TEM,SHV,CTX-M,OXA and the others. ESBLs were produced by Gram-negative bacteria(mainly by Escherichia coli and klebsiella pneumoniae). ESBLs was the main reason of Gram-negative bacteria drug- resistant toβ-lactam antibiotic. And the resistance of ESBLs-producing strains has currently become one of the most important nosocomial resistance problems in hospitals around the world. The isolating rate of ESBLs-producing strains is increasing year by year. The study of ESBLs has become a new hot point of bacteria's drug resistance mechanism.The main pathogenic bacteria of UTI are Gram-negative bacteria, the most common phathogenic bacteria are E-coli which constitute about 70 percent of total pathogenic bacferia. The others include bacillus proteus, Klebsiella,aeruginosus bacillus etc. As time goes on, and the wide spread use of antibiotic, the drug resistance of E-coli increased by wide margin. Multiple drug resistance bacteria increased harply, drug resistance pedigree increased. In order 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 E.coli isolates in Hefei,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.As the wild use of antibiotics,the drug-resistance of bacteria and produce of ESBLs vary every year. Though the investigate and analysis of bacteria of the midstream urine of the patients who suffered from UTI, we understand the condition of the bacteria drug-resistance pedigree and go a step to find out the drug-resistance of E-coli separated from uriary tract,the produce of ESBLs and initially classify the drug-resistance gene of E-coli which produce ESBLs.Objective 1.To study the best detective substrate of ESBLs-producing E.coli which induce urinary tract infection from our hospital. 2.To investigate the distribution of the bacterial in urinary tract infection,epidemiological data and resistance of ESBLs producers of our hospital in 2008. 3.To study resistant genotypes of ESBLs producers in urinary tract infection in our hospital. 4.To suggest the plan to control the urinary infection caused by E.coli.Materials and Methods We collect clinical strains from medistream urine which was clinical definited urinary tract infection from January to December in 2008, and identified sample using MicroScan WalkAway-40 system. Susceptibility test were detected by applying K-B method and ESBLs test to Escherichia Coli infected urinary samples.ESBIs producers were screened by ESBLs initial screening test and phenotype comfirmatory test in accordance to the guidelines of CLSI in 2008,respectively.Nine pairs of primers were designed in accordance to the basic sequences of blaTEM, blaSHV, blaCTX ,blaOXA in the GenBank,respectively. PCR was performed with the nine pairs primers respectively. Results We fetch the samples of urina of the out patients and in patients whose clinical diagnosis were urinary defection.The number of positive culture results is 926, among them were 336 E-coli. The detection rate of Escherichia Coli is 36.0%, and the next rate is Staphylococcus. Escherichia Coli have a low drug tolerance rate for imipenem, piperacillin/Tazobactam,amikacin,ticar/K Clav, Amoxicillin/ K Clav and cefoxitin, which are 0.9%,5.4%,7.1%,9.8%,10.7% and 14.3% respectively. As for other commonly used antibiotics, the rates are all over 50%. Besides, ESBLs(+)bacterium shows a upward detection rate and generally has a higher drug tolerance rate than ESBLs(-)bacterium, which have statistical significance (P<0.025). PCR results showed that there were 54 strains TEM-type(16.1%), 3 strains SHV type(0.9%), 219 strains CTX-M-type(65.2%)and 9 strains OXA-type(2.7%)in ESBLs-producing E.coli isolates. The results of conjugation test showed that resistance were transfer by plasmid.Conclusion 1.With an increasing detection rate and enzyme-producing rate of Escherichia Coli in urinary tract infection, clinicians should choose antibiotics based on susceptibility test. 2.The results showed that the incidence of ESBLs producers was high in E.coli isolates and there was wide prevalence. ESBLs of E.coli was 36.29%. And CTX was the best detective substrate of ESBLs. 3. Drug-resistant data showed that ESBLs-producing E.coli isolates was often multidrug- resistant organisms. Carbapenems like IMP were most reliable therapeutic drugs. 4.The main genotype of ESBLs was CTX-M-type,and many strains carried two or more gene. 5. The CTX-M-14-type genes of ESBLs are predominate. At the same time CTX-M-1 and CTX-M-8 have spreaded.