Identification of Urovirulence Traits inEscherichia coliby Comparison of Urinary and RectalE. coliIsolates from Dogs with Urinary Tract Infection

Abstract

Spontaneously occurring urinary tract infection (UTI) in dogs was exploited as an experiment of nature to gain insights into UTI pathogenesis in humans. Concurrent urinary and rectal Escherichia coli isolates from 37 dogs with UTI were compared with respect to phylogenetic background, O antigens, and extended virulence genotype. In 54% of the UTI episodes, the dog's urinary and rectal isolates represented the same strain. Urinary isolates differed dramatically from rectal-only isolates in that they derived predominantly from E. coli phylogenetic group B2, expressed typical (human) UTI-associated O antigens, and possessed many virulenceassociated genes, most notably pap elements (P fimbriae), papG (adhesin) allele III, sfa/foc and sfaS (S fimbriae), hly (hemolysin), fyuA (yersiniabactin), iroN (siderophore), and ompT (outer membrane protease T). The 20 urinary isolates that corresponded with the host's predominant rectal strain were no less virulent according to the markers analyzed than were the 17 urinary isolates that differed from the host's predominant rectal strain. These findings suggest that UTI pathogenesis is similar in dogs and humans, provide added support for the special-pathogenicity over the prevalence hypothesis of UTI pathogenesis, and identify numerous specific virulence-associated factors as significant correlates of urovirulence. Dogs spontaneously develop urinary tract infection (UTI)due to strains of Escherichia coli similar to those that cause UTI in humans (4, 6, 7, 15, 18, 25, 30, 42, 45-47, 50, 51). In both host groups, the urinary pathogens typically derive from specific clonal groups within virulence-associated E. coli phylogenetic group B2, express one of several UTI-associated O antigens, and possess specialized virulence-associated factors (VFs) that directly contribute to, or are markers for, an enhanced ability to overcome host defenses and cause extraintestinal disease (15,18,25,41). In both dogs (18, 30) and humans (8,40,49) at the time of a UTI episode, the infecting urinary strain is often the host's predominant rectal E. coli strain, consistent with the fecal reservoir as the proximate source from which pathogens enter the urinary tract. Even healthy dogs are frequently intestinally colonized with uropathogenic E. coli and shed these organisms in their feces (23,50,51).These observations are potentially relevant to human health because they suggest that dogs may pose an infectious threat to humans by providing a reservoir of "human" uropathogenic E. coli for acquisition by susceptible human hosts (15,18,23,25,30,45). In addition, they suggest that the pathogenesis of UTI is similar in dogs and humans, so that dogs might serve as a pathogenetically relevant model system for observational or experimental studies of UTI pathogenesis (15,25).Accordingly, in the present study we took advantage of spontaneously occurring UTI in dogs to address several questions regarding the pathogenesis of UTI in humans. In 37 dogs with UTI, which served as their own controls, we compared concurre...

Association between virulence profile and fluoroquinolone resistance in Escherichia coli isolated from dogs and cats in China

“…Usually, E. coli isolates can be classified into commensal, intestinal pathogenic, and extraintestinal pathogenic E. coli (ExPEC) groups, based on different virulence genes [2]. ExPEC usually possesses diverse virulence genes responsible for pathogenesis outside the gastrointestinal tract, and is also distinguished from commensal E. coli by the presence of a broad spectrum of virulence genes [3][4][5], while commensal isolates can also develop into intestinal or ExPEC isolates by acquiring virulence genes [2][3][4][5][6][7].…”

Association between Presence of Urovirulence Factors, Phylogenetic Class, and Antimicrobial Resistance Patterns in 159 Uropathogenic <i>Escherichia coli</i> Samples Isolated from Dogs

“…Virulence factors are present in increased numbers in E. coli that infect the urinary tract compared to E. coli that are present only in the rectum [5,6]. Several urovirulence factors (UVFs) have been associated with canine uropathogenic E. coli (UPEC), including adhesion-encoding operons (pilus associated with pyelonephritis gene G allele III [pap]), s-fimbrial adhesion gene [sfa]), hemolysin (hly), cytotoxic necrotizing factor (cnf), and aerobactin (aer) [5][6][7]. In one study of 12 dogs with persistent or recurrent UTIs, 70% of the UPEC were positive for at least one UVF [8].…”

Preventing canine urinary tract infection (UTI) using an asymptomatic bacteriuria (ASB) Escherichia coli strain

“…An E. coli isolate may be classified as an extraintestinal pathogenic E. coli (ExPEC) if it satisfies certain criteria with regard to virulence gene carriage; it must exhibit > 2 of pap (P fimbriae), sfa/foc (S/F1C fimbriae), afa/dra (Dr binding adhesins), iutA (aerobactin receptor), and kpsMT II (group 2 capsule synthesis) virulence genes (Johnson et al, 2003b). Most ExPEC in humans, including those associated with UTI, belong to phylogenetic group B2 (isolates in this group are generally found to contain more virulence genes) and to a lesser extent group D, and a similar distribution has been reported in dogs (Picard et al, 1999;Clermont et al, 2000;Johnson et al, 2003a;Platell et al, 2011c). These groups of organisms are phylogenetically distinct from commensal and intestinal E. coli, which predominantly belong to groups A and B1 (Picard et al, 1999;Tenaillon et al, 2010).…”

“…Virulence factors of importance to uropathogenic E. coli (UPEC) include capsular factors, cytotoxins, invasion factors (invasins), siderophores and related transport systems, as well as adhesins that mediate binding to the renal tubule (P, S and F1C fimbriae) and bladder urothelium (type 1 fimbriae) (Yuri et al, 1998b, a;Johnson et al, 2003a). This is likely to be of particular importance in dogs with intact urinary tract defence mechanisms because to establish a UTI, host defences must be overcome.…”

“…As E. coli isolates from canine and human sources share close phylogenetic and pathotypic similarities (Low et al, 1988;Johnson et al, 2003aJohnson et al, , 2009a, it is possible that the long-term colonisation of dogs by E. coli 83972 may also prevent chronic, symptomatic UTI. Therefore, the aim of the current study was to determine if persistent bacteriuria with E. coli 83972 could be achieved in healthy dogs following a single bladder inoculation.…”