evaluation of biofilm formation among klebsiella pneumoniae isolates and molecular characterization by eric-pcr

Background: klebsiella pneumoniae is among the most frequently recovered etiologic agents from nosocomial infections. this opportunistic pathogen can generate a thick layer of biofilm as one of its important virulence factors, enabling the bacteria to attach to living or abiotic surfaces, which contributes to drug resistance. objectives: the resistance of biofilm-mediated infections to effective chemotherapy has adverse effects on patient outcomes and survival. therefore, the aim of the present study was to evaluate the biofilm-formation capacity of clinical k. pneumoniae isolates and to perform a molecular characterization using enterobacterial repetitive intergenic consensus-polymerase chain reaction (eric-pcr) to determine the dominant biofilm-producing genotype. patients and methods: in the present study, 94 k. pneumoniae isolates were obtained from two hospitals in tehran, iran. biofilm formation was assayed by a modified procedure, then eric-pcr was carried out. results: the distributions of the clinical specimens used in this study were 61.7% from urine, 18.1% from wounds, 11.7% from sputum, and 8.5% from blood. among these isolates, 33% formed fully established biofilms, 52.1% were categorized as moderately biofilm-producing, 8.5% formed weak biofilms, and 6.4% were non-biofilm-producers. genotyping of k. pneumoniae revealed 31 different eric types. biofilm- formation ability in a special eric type was not observed. conclusions: our results indicated that an enormous proportion of k. pneumoniae isolated from sputum and surgical-wound swabs produced fully established biofilms. it is reasonable to assume the existence of a relationship between the site of infection and the formation of biofilm. a high level of genetic diversity among the k. pneumoniae strains was observed.