Extraintestinal Pathogenic and Antimicrobial-Resistant Escherichia coli Contamination of 56 Public Restrooms in the Greater Minneapolis-St. Paul Metropolitan Area

Abstract

How extraintestinal pathogenic Escherichia coli (ExPEC) and antimicrobial-resistant E. coli disseminate through the population is undefined. We studied public restrooms for contamination with E. coli and ExPEC in relation to source and extensively characterized the E. coli isolates. For this, we cultured 1,120 environmental samples from 56 public restrooms in 33 establishments (obtained from 10 cities in the greater Minneapolis-St. Paul, MN, metropolitan area in 2003) for E. coli and compared ecological data with culture results. Isolates underwent virulence genotyping, phylotyping, clonal typing, pulsed-field gel electrophoresis (PFGE), and disk diffusion antimicrobial susceptibility testing. Overall, 168 samples (15% from 89% of restrooms) fluoresced, indicating presumptive E. coli: 25 samples (2.2% from 32% of restrooms) yielded E. coli isolates, and 10 samples (0.9% from 16% of restrooms) contained ExPEC. Restroom category and cleanliness level significantly predicted only fluorescence, gender predicted fluorescence and E. coli, and feces-like material and toilet-associated sites predicted all three endpoints. Of the 25 E. coli isolates, 7 (28%) were from phylogenetic group B2(virulence-associated), and 8 (32%) were ExPEC. ExPEC isolates more commonly represented group B2 (50% versus 18%) and had significantly higher virulence gene scores than non-ExPEC isolates. Six isolates (24%) exhibited >3-class antibiotic resistance, 10 (40%) represented classic human-associated sequence types, and one closely resembled reference human clinical isolates by pulsed-field gel electrophoresis. Thus, E. coli, ExPEC, and antimicrobial-resistant E. coli sporadically contaminate public restrooms, in ways corresponding with restroom characteristics and within-restroom sites. Such restroom-source E. coli strains likely reflect human fecal contamination, may pose a health threat, and may contribute to population-wide dissemination of such strains. E scherichia coli is a major cause of urinary tract and other extraintestinal infections, resulting in considerable morbidity, mortality, and costs (1). Most such infections are caused by distinctive E. coli strains called extraintestinal pathogenic E. coli (Ex-PEC) because of their enhanced ability to invade and cause disease at extraintestinal sites (2). Such strains' main reservoir is the human intestinal tract, where they usually reside harmlessly as longterm colonizers (3). ExPEC strains can be distinguished from other E. coli strains by their extensive virulence gene repertoire and primarily group B2 phylogenetic background (2).Dissemination of virulent and antimicrobial-resistant E. coli clones through the human population has been recognized recently as an important contributor to the overall burden of Ex-PEC-associated disease (4-7). However, the mechanisms of such clonal dissemination remain undefined. Flush toilets create microdroplets containing viable bacteria (8, 9), and both public and private restrooms have been shown to be variably contaminated with human-source bacteri...

Phylogenetic Backgrounds and Virulence-Associated Traits of Escherichia coli Isolates from Surface Waters and Diverse Animals in Minnesota and Wisconsin

“…Other humans who are colonized with ExPEC and phylogroup B2 strains undoubtedly are an important source for new acquisitions, since such strains are relatively common among healthy humans, and cohabiting individuals share intestinal E. coli strains extensively, suggesting that person-to-person transmission occurs (8)(9)(10)(11). Additionally, previous work, including studies by some of the present authors, identified ExPEC strains of potential human health relevance, including those from phylogroup B2, in diverse nonhuman reservoirs, such as retail food products (12,13), public restrooms (14), household pets (10,15,16), and environmental waterways (17)(18)(19). This supports the existence of environmental reservoirs of ExPEC.…”

“…Consistent with the possibility that the present chicken and turkey source ExPEC isolates may represent APEC, they lacked sfa/foc, hlyD, and malX, as do many APEC strains, whereas many ExPEC strains from humans, cats, and dogs possess these traits b,c,d No. of isolates with indicated trait (column %) P value e Total (n ‫؍‬ 21) Goat (n ‫؍‬ 1) Cat (n ‫؍‬ 9) Dog (n ‫؍‬ 4) Horse (n ‫؍‬ 1) Chicken (n ‫؍‬ 1) Turkey (n ‫؍‬ 4) Pig (n ‫؍‬ 1) papG II 3 (14) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 3 (75) 0 (0) 0.02 sfa/foc 14 papA, P fimbrial structural subunit (52%); papC, P fimbrial assembly (71%); papEF and papG, P fimbrial tip pilins and adhesin (57% each); papG I, variant P adhesin (11%); papG III, variant P adhesin (38%); sfaS, S fimbriae (5%); focG, F1C fimbriae (43%); iha, adhesin-siderophore (5%); fimA, type-1 fimbrial adhesin (100%); cnf1, cytotoxic necrotizing factor (48%); cdtB, cytolethal distending toxin B (24%); iroN, salmochelin receptor (86%); ireA, siderophore (29%); K1 capsule kpsM variant (10.5%); kpsMT III, group 3 capsule (5%); rfc, O4 lipopolysaccharide (11%); cvaC, colicin (microcin) V (24%); traT, serum resistance associated (43%); ibeA, invasion of brain endothelium (5%); ompT, outer membrane protease (71%); iss, increases serum survival (24%). d Traits sought but not detected: afa/draBC (Dr-binding adhesins), bmaE (M fimbriae), gafD (G fimbriae), K2/K100 kpsM variant, and fliC (H7 flagellar variant).…”

Isolation and Characterization of <i>Escherichia coli</i> from Animals, Humans, and Environment

“…Beta-glucuronidase positive isolates will appear purple on Brilliance E. coli agar or dark-green on Petrifilm Select E. coli count plate. The use of chromogenic media is usually followed by analyses by other techniques, for example, PCR, PFGE, or sequencing [20].…”

“…Isolation of E. coli for EXPEC detection can follow methods that have been mentioned previously for other pathotypes. Detection of EXPEC can be done by multiplex PCR targeting different genes some of which have been previously described and dot blot hybridization [1,20,27,28]. Typing of isolates from different sources can be done by different procedures including PFGE [20].…”

Antimicrobial-Resistant Escherichia coli Distribution and Whole-Genome Analysis of Sequence Type 131 Escherichia coli Isolates in Public Restrooms in Taiwan

“…Therefore, the threat of antibiotic-resistance genes to public health may originate from public restrooms and sewage ( Mkrtchyan et al, 2013 ; Pepper et al, 2018 ; Hendriksen et al, 2019 ). Few studies have surveyed public restrooms for environmental ESBL-producing E. coli ( Mohamed et al, 2015 ). To better understand the burden of ESBL-producing or ceftriaxone-resistant E. coli and ST131 E. coli in public restrooms, we performed surveillance in public restrooms in southern Taiwan.…”