Multilocus sequence typing of Escherichia coli isolates from urinary tract infection patients and from fecal samples of healthy subjects in a college community

• Published in: MicrobiologyOpen (Weinheim) Vol. 9; no. 6; pp. 1225 - 1233
• Main Authors: Matsui, Yusuke, Hu, Yuan, Rubin, Julia, Assis, Reginara Souza, Suh, Joy, Riley, Lee W.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.06.2020; John Wiley and Sons Inc; Wiley
• Subjects: Antibiotics; Bacterial diseases; Bacterial infections; Bladder; commensal E. coli; Drug resistance; E coli; Escherichia coli; Feces; Genes; Genotypes; Health care facilities; Intestine; Laboratories; Lactose; molecular epidemiology; Multilocus sequence typing; Original; Pathogens; Patients; Questionnaires; Rectum; Subgroups; Urethra; Urinary tract; Urinary tract diseases; urinary tract infection; Urinary tract infections; Urine; Urogenital system; uropathogenic E. coli; United States > US; California; molecular epidemiology; multilocus sequence typing; commensal E. coli; uropathogenic E. coli; Escherichia coli; urinary tract infection
• ISSN: 2045-8827; 2045-8827
• DOI: 10.1002/mbo3.1032

Community‐acquired urinary tract infections (UTIs) are one of the most common bacterial infections worldwide. Escherichia coli is the most common cause of community‐acquired UTI. In general, UTI results from E. coli in the intestine that enters the bladder via the urethra. However, whether these E. coli strains that cause UTI represent members of the intestinal commensal E. coli or a distinct subgroup of pathogenic E. coli remains unestablished. Here, we analyzed E. coli isolates from fecal samples of healthy volunteers and urine samples of UTI patients obtained from a university‐affiliated health center. The E. coli isolates were genotyped by multilocus sequence typing (MLST). From May to October 2018, we analyzed 89 E. coli isolates from 76 (75%) rectal swabs from 113 unique healthy volunteers. We also analyzed 106 (27%) E. coli isolates from 398 unique urine samples collected between August and October 2018. Fecal and urine E. coli isolates each contained 31 distinct sequence types (STs). Nine STs were shared by fecal and urine E. coli isolates, which accounted for approximately 50% of urine isolates typed by MLST. Among the shared genotypes, ST10 and ST131 were significantly more frequently found in fecal samples, whereas ST95 and ST127 were significantly more frequently recovered from UTI samples. ST73 was found only among urine samples. These E. coli genotypes clustered and fluctuated over time. These observations suggest that E. coli genotypes found to cause UTI transiently colonize the intestine and that their primary reservoir may reside outside of the human intestine. We address an unresolved question regarding the source of Escherichia coli that causes community‐acquired urinary tract infection (CA‐UTI)—whether E. coli strains that cause UTI represent members of the intestinal commensal E. coli or a distinct subgroup of pathogenic E. coli. Our results based on multilocus sequence type (MLST) analysis of E. coli isolates from healthy volunteers versus urine isolates from patients with UTI indicate that uropathogenic E. coli has a source outside of the human intestine.