Biofilm formation by uropathogenic Escherichia coli: a complicating factor for treatment and recurrence of urinary tract infections.

BACKGROUND: Uropathogenic Escherichia coli (UPEC) are the principal cause of urinary tract infections (UTIs) which can be either hospital- or community-acquired. The most crucial factor in the persistence and recurrence of UTIs is the biofilm formation ability of UPEC, which protects them against antimicrobial treatment. AIM: To investigate the genetic relatedness, biofilm formation ability, and biofilm-related genes in UPEC isolated from hospital- and community-acquired UTI patients. METHODS: In vitro biofilm formation ability of 100 UPEC isolates, collected from the urine samples of 49 inpatients and 51 outpatients with UTIs, was assessed by the microtitre plate method. The association between the presence of fimH, papC, sfa/focDE, csgA, crl, afa, flu, and bcsA genes and biofilm formation ability of UPEC was statistically analysed. The genetic relatedness of UPEC isolates was evaluated by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). FINDINGS: Overall, 99% of the UPEC isolates showed in vitro biofilm formation ability, and 27% of the isolates were moderate to strong biofilm producers. Only the presence of sfa/focDE gene was significantly associated with moderate and strong biofilm formation by the UPEC isolates. Analysis of dendrograms revealed higher genetic similarities among UPEC isolates of inpatients compared with outpatients. CONCLUSION: Based on the results, selection of effective therapeutic approaches, which can affect both biofilm formation and enclosed UPEC, is important for preventing recurrent UTIs. The common UPEC clones among inpatients in different hospital units emphasize the need for more rigid control measures to prevent the spread of UPEC in hospitalized patients and to reduce the occurrence of hospital-acquired UTIs.

DNA fingerprinting approaches to trace Escherichia coli sharing between dogs and owners.

AIMS: To determine the prevalence of cross-species sharing of Escherichia coli between healthy dogs and humans living in the same household. METHODS AND RESULTS: Two faecal E. coli isolates from 25 healthy dog-owner pairs and 16 healthy control humans were tested using three fingerprinting methods. The prevalence of within-household sharing of E. coli was 4, 8 and 8% using pulsed-field gel electrophoresis, randomly amplified polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR analyses respectively. Within-household bacterial sharing was more prevalent than across-household sharing (P < 0·05). According to questionnaire analyses avoiding the dog-owner behaviours such as allowing a dog to kiss or lick the owner's face, sharing people food with dog and feeding it raw meat may decrease the chance of cross-species E. coli sharing. CONCLUSIONS: Direct contact between humans and dogs and environmental reservoirs may be important routes for cross-species sharing of bacteria. Good personal hygiene and appropriate veterinary care for pets can minimize this risk. SIGNIFICANCE AND IMPACT OF THE STUDY: Due to the importance of canine pathogenic E. coli reservoir hypothesis, close contacts between humans and dogs raises public health concerns. Determining the rate of cross-species bacterial sharing and confirm its accuracy by different fingerprinting techniques will help to find ways for reducing the economic impact of E. coli infections. This study support claims that public health concerns regarding the cross-species sharing of E. coli are warranted but this risk is minimal.