Similarity and Divergence of Phylogenies, Antimicrobial Susceptibilities, and Virulence Factor Profiles of Escherichia coli Isolates Causing Recurrent Urinary Tract Infections That Persist or Result from Reinfection

Abstract

In order to obtain a better molecular understanding of recurrent urinary tract infection (RUTI), we collected 75 cases with repeatedly occurring uncomplicated UTI. The genetic relationships among uropathogenic Escherichia coli (UPEC) isolates were analyzed by pulsed-field gel electrophoresis. While 39 (52%) of the RUTI cases were defined as "persistence" of the same strain as the primary infecting strain, 36 (48%) were characterized by "reinfection" with a new strain that is different from the primary strain. We then examined the antimicrobial susceptibilities and phylogenetic backgrounds of 39 persistence and 86 reinfection UPEC isolates, and screened 44 virulence factor (VF) genes. We found that isolates had significant differences in the following: placement in phylogenetic group B2 (41% versus 21%; P ‫؍‬ 0.0193) and the presence of adhesin genes iha (49% versus 28%; P ‫؍‬ 0.0233) and papG allele I= (51% versus 24%; P ‫؍‬ 0.003), iron uptake genes fyuA (85% versus 58%; P ‫؍‬ 0.0037), irp-2 (87% versus 65%; P ‫؍‬ 0.0109), and iutA (87% versus 58%; P ‫؍‬ 0.0014), and an aggregate VF score (median, 11 versus 9; P ‫؍‬ 0.0030). In addition, 41% of persistence strains harbored three adhesin genes simultaneously, whereas 22% of reinfection isolates did (P ‫؍‬ 0.0289). Moreover, 59% versus 29% (P ‫؍‬ 0.0014) of persistence and reinfection isolates contained seven types of iron uptake genes. Taken together, the antimicrobial susceptibilities of UPEC isolates had little effect on the RUTI. Compared with reinfection strains, persistence UPEC isolates exhibited higher VF scores and carried more VF genes than may be involved in the development and progression of RUTI.A bout half of all women experience at least one urinary tract infection (UTI) during their lifetime, and UTIs are the second most common infection and account for nearly 25% of all infections in noninstitutionalized elderly populations (13). Moreover, about 25% to more than 40% of patients with UTIs experience recurrent UTI (RUTI) within weeks or months (3,11,13,16,32).As the most predominant pathogen, uropathogenic Escherichia coli (UPEC) causes almost 75 to 95% of episodes of uncomplicated UTIs (11,16). Some studies suggest that RUTI is primarily caused by a new strain that is quite different from the original strain (reinfection with a new strain) (4, 22). However, other studies indicate that most (50 to 78%) of the recurrent strains are indistinguishable compared with the original strains (persistence of the original strain) (12,14,18,24,37,39). The persistence of UPEC within the bladder could be due to the fact that UPEC strains can persist in the fecal flora for years and cause recurrent ascending UTIs (16). However, RUTI cannot be prevented by daily topical antibiotic treatment of the perineum, suggesting that RUTI does not require pathogen migration from the anus to the urinary tract (17). Furthermore, the intracellular bacterial reservoirs can persist for weeks to months within the urothelium, and intracellular biofilm-like collections of bacteria h...

Detection of virulence genes, phylogenetic group and antibiotic resistance of uropathogenic Escherichia coli in Mongolia

“…In the present study, the predominant phylogenetic group was B2 (33.8%), followed by D (28.4%), A (19.6%), and B1 (18.2%). Comparing to researchers' results from China, geographically located closest to our country, Luo et al [29] and Cao et al [30] reported the most common phylogenetic group in the UPEC isolates was B2 and D. Our results support these findings. Phylogenetic group A, associated with commensal strains, represented 19.6% of isolates, which was higher than in some studies [31,32], suggesting that the gastrointestinal tract is the main reservoir of strains that may be able to colonize the urinary tract, in accordance with previous observations.…”

Phenotypic Identification and Phylogenetic Characterization of Uropathogenic Escherichia coli in Symptomatic Pregnant Women With Urinary Tract Infections in South-Western Nigeria

“…Prevalence of chuA gene in most of the representative isolates in the study may be a pointer to the significance of iron acquisition in the pathogenesis and urovirulence of UPEC. Greater percentage (60%) of isolates in the study belonged to phylogroup D hence, corroborates the reports of Yanping et al (2012) who reported that the predominant group of UPEC recovered from UTI patients in their study belonged to phylogroup D. The finding also agrees with the report of Cao et al (2011), in a multicenter study in China, where larger percentage (54%) www.ccsenet.org/ijb International Journal of Biology Vol. 6, No.…”

Virulence Characteristics and Antibiotic Resistance Patterns among Various Phylogenetic Groups of Uropathogenic <i>Escherichia coli</i> Isolates

“…Previously, this gene was detected in approximately 77z of UPEC isolates causing recurrent UTI in China and in 85.5z of UPEC isolates in the United States (15,24). In the study performed by Luo et al (sitA ＝ 77z), UPEC phylogenetic group D was the most prevalent, followed by groups B2 and then A (24). However, our findings indicate that the frequency of phylogenetic group A was more than twice that of the others.…”

“…To the best of our knowledge, there are no published data pertaining to the presence of sitA in UPEC isolates from Iran. Previously, this gene was detected in approximately 77z of UPEC isolates causing recurrent UTI in China and in 85.5z of UPEC isolates in the United States (15,24). In the study performed by Luo et al (sitA ＝ 77z), UPEC phylogenetic group D was the most prevalent, followed by groups B2 and then A (24).…”