Is there any difference between characteristics of nosocomial andcommunity-acquired uropathogenic E. coli isolates?

BACKGROUND AND OBJECTIVESNosocomial and community-acquired uropathogenic Escherichia coli (UPECs), the most commoncausative pathogen of urinary tract infection (UTI), have different phenotypic patterns which lead tothe diversity in their pathogenicity, including the antibiotic resistance, influenced by differences inphylogenetic and biofilm formation ability. This study was conducted to evaluate the relationshipbetween antibiotic resistance pattern and these characteristics in UPECs recovered from in-/outpatientswith UTI in two hospitals of Tehran.Materials and methodsFrom December ۲۰۲۲ to March ۲۰۲۳, bacterial samples were collected from the urine of UTI patientswho referred to/hospitalized in Imam and Loghman hospitals. Of these, E. coli bacteria wereconfirmed using biochemical methods and PCR. Phylogenetic grouping was investigated usingmultiplex-PCR, and antibiotic sensitivity was determined using disc diffusion assay. Biofilmformation in the isolates was assessed using the microtiter assay.RESULTS AND DISCUSSIONSixty E. coli isolates (۳۰ from each hospital) were recovered. Of these, ۳۰ were isolated from inpatients(۱۵ from each hospital) and ۳۰ from out-patients, where the ratio of men and women wasalmost equal. Among the isolates, ۹۳% were MDR; more than half of them (۵۴%) were resistant to ۱۰antibiotics or more (highly resistant), while others were resistant to ۳ to ۹ antibiotics (regular MDR).The ratio of the highly resistant isolates was nearly three times higher at Imam Hospital and more thantwo times higher in in-patients. In contrast, regular MDRs were more than twice at LoghmanHospital, and although nonsignificantly, more prevalent among out-patients. Phylogroup B۲ was themost common (۵۲% of isolates), followed by F and E group (۲۳% and ۱۰% respectively). Inphylogroup F, the ratio of highly resistant isolates was ۲.۵ times higher. In phylogroup A (۳% ofisolates) all were highly resistant. The isolates with higher antibiotic resistance formed weak or nobiofilm. Logically, those that have not formed biofilm were all from Imam Hospital, and those thatformed strong biofilm belonged to Loghman Hospital.CONCLUSIONIt seems that the more resistant UPECs are to antibiotics, the weaker biofilm they form. Although itmight be obvious that the UPECs in hospitals are more resistant than the ones in community, thisstudy shows that resistance pattern might depend more on the hospital itself.

کلیدواژه ها:

Urinary tract infection ، E. coli ، antibiotic resistance ، multidrug resistant ، nosocomial infection