Relationship between virulence factors, resistance to antibiotics and phylogenetic groups of uropathogenic Escherichia coli in two locations in Mexico. / Relación entre factores de virulencia, resistencia a antibióticos y los grupos filogenéticos de Escherichia coli uropatógena en dos localidades de México.

INTRODUCTION: Escherichia coli is the major causative agent of urinary tract infections (UTI), and virulence factors are responsible for the severity of these emerging infections. The aim of this study was to evaluate the relationship between virulence determinants and antibiotic susceptibility with phylogenetic groups of E.coli isolates of UTI in two locations in Mexico. METHODS: An analysis was performed on 50 isolates of E.coli from the centre of the country and 57 from a town in the southwest. The isolates were characterized by phenotype (serotyping assays, in vitro adhesion, biofilm formation, production of haemolysin, and antibiotic susceptibility) and genotype (phylogenetic groups and virulence genes). RESULTS: In the centre of the country location the phylogenetic group B2 (60%) and F (12%) were significantly more prevalent and had a higher frequency of genes, fimH (96%), iutA (66%), sat (36%), compared to the southwest location, where the group A (35%) and B1 (21%) were significantly predominant and had fewer virulence genes. About one-fifth (21.5%) of all isolates belonged to the O25-ST131 group. Haemolysin and biofilm producing strains were significantly higher in the southwest location. Resistance to ampicillin (92.5%), tetracycline (76.6%), and trimethoprim/sulfamethoxazole (70.1%) were the most common in both groups. CONCLUSION: The phylogenetic group, virulence factors, and antibiotic susceptibility of the E.coli that causes UTI in the community, varies significantly among the Mexican populations studied. Phylogenetic groups A and B1 may be multidrug resistant and have the ability to produce UTI.

Enteroaggregative Escherichia coli is associated with antibiotic resistance and urinary tract infection symptomatology.

BACKGROUND: Uropathogenic Escherichia coli (UPEC) is the causative agent of uncomplicated urinary tract infections (UTIs) in ambulatory patients. However, enteroaggregative E. coli (EAEC), an emergent bacterial pathogen that causes persistent diarrhoea, has recently been associated with UTIs. The aim of this study was to determine the frequency of EAEC virulence genes, antibiotic resistance, as well as biofilm production of UPEC isolates obtained from ambulatory patients with non-complicated UTIs that attended to the ISSSTE clinic in Chilpancingo, Guerrero, Mexico, and correlate these with the patients' urinary tract infection symptomatology. METHODS: One hundred clinical isolates were obtained. The identification of clinical isolates, antimicrobial susceptibility testing, and extended spectrum beta-lactamases (ESBLs) production were performed using the Vitek automated system. Assignment of E. coli phylogenetic groups was performed using the quadruplex phylo-group assignment PCR assay. UPEC virulence genes (hlyA, fimH, papC, iutA, and cnf1) and EAEC virulence genes (aap, aggR, and aatA) were detected by multiple PCR. RESULTS: We found that 22% of the isolates carried the aggR gene and were classified as UPEC/EAEC. The main phylogenetic group was B2 (44.1% were UPEC and 77.27% UPEC/EAEC isolates, respectively). Over half of the UPEC/EAEC isolates (63.64%) were obtained from symptomatic patients, however the aatA gene was the only one found to be associated with the risk of developing pyelonephritis (OR = 5.15, p = 0.038). A total of 77.71% of the UPEC/EAEC isolates were ESBL producers and 90.91% multidrug-resistant (MDR). In conclusion, UPEC/EAEC isolates are more frequent in symptomatic patients and the aatA gene was associated with a higher risk of developing pyelonephritis, along with UPEC genes hlyA and cfn1. UPEC/EAEC isolates obtained from UTI showed ESBL production and MDR.

Association between TLR4 polymorphisms (896 A>G, 1196 C>T, - 2570 A>G, - 2081 G>A) and virulence factors in uropathogenic Escherichia coli.

Escherichia coli is the main etiological agent of urinary tract infections. Its virulence factors are important during the initial interaction stage with the host as they enable colonization of urinary tract tissues. The genetic markers evidencing susceptibility to develop recurrent infections have been previously described. Toll-like receptors are critical sensors of microbial attacks, and they are also effectors of the individual's innate defense for elimination of pathogens. The aim of this study was to evaluate the association between functional polymorphisms (896 A>G, 1196 C>T, - 2570 A>G, - 2081 G>A) and susceptibility to develop urinary tract infections as well as E. coli virulence factors. This study includes 100 samples from patients diagnosed with UTI and 100 samples from uninfected subjects. A conventional urine culture was performed and the isolates were identified by using the Vitek automated system. TLR4 gene polymorphisms were identified by the PCR-RFLP technique. The hlyA, fimH, papC, iutA and cnf1 virulence factors as well as the E. coli phylogenetic group were assessed by PCR. In this study, it was observed that the presence of the - 2570 polymorphism represents a risk of UTI (p < 0.01), whereas - 2081 confers protection (p < 0.01). The 896A>G and 1196C>T polymorphisms were associated with the E. coli virulence factors fimH and hlyA, respectively (p < 0.05). The B2 group was the most frequent in clinical isolates (51%), and it displayed more virulence factors regarding other phylogenetic groups (p ≤ 0.05). An interesting finding was that strains considered as commensals, belonging to groups A and B1, can cause UTI and present virulence factors. Polymorphisms occurring in the TLR4 promoter region are correlated with susceptibility or risk of UTI, whereas structural polymorphisms are associated with the recognition of virulence factors displayed by E. coli.