Detection of the biofilm formation ability and the extended spectrum β-lactamase of Escherichia coli clinical isolates

Objective To understand the biofilm-formation ability and drug resistance characteristics of Escherichia coli clinical isolates,in order to provide a theoretical basis for the clinical application of antibiotics.Methods The method of microtiterplate culture-crystal violet stain was established for the quantificative analysis of the biofilm-formation of 389 Escherichia coli isolates.Extended spectrum β-lactamases(ESBLs) was detected by phenotypic confirmatory test and K-B method was used for susceptibility test.Results Among 389 Escherichia coli isolates examined,301 of them formed biofilm,the positive rate was 77.4%,most of the Escherichia coli isolates formed the middle quantity or a large number of biofilm;160 bacteria produced Extended spectrum β-lactamases among 301 Escherichia coli biofilm bacteria,accounting for 53.2%;the biofilm bacteria producing extended spectrum β-lactamases had higher drug resistance rate to 12 antibiotics except imipenem.Conclusion Escherichia coli clinical isolates have very strong biofilm formation ability.The drug resistance and multidrug resistance of these isolates are more serious.