Drug resistance, serotypes, and phylogenetic groups among uropathogenic Escherichia coli including O25-ST131 in Mexico City

Abstract

Introduction: The increasing prevalence of uropathogenic Escherichia coli (UPEC) strains resistant to multiple antibiotics complicates the treatment of urinary tract infections (UTIs). This study aimed to analyze the antimicrobial resistance, serotypes, and phylogenetic groups among strains of E. coli isolated from outpatients with UTIs in Mexico City. Methodology: A total of 119 E. coli isolates were recovered from urine samples from outpatients with clinical diagnosis of uncomplicated UTIs from 2004 to 2007. The serotype was assessed by agglutination in microtiter plates; susceptibility to antimicrobials was determined by the disk diffusion method. Clone O25-ST131 and phylogenetic groups of E. coli strains were tested by methods based on PCR multiplex. Results: The predominant serotype was O25:H4 (21.2%). Resistance to antibiotics was ampicillin (83.7%); piperacillin (53.8%); the fluoroquinolone group (55.5-60.6%), and trimethoprim/sulfamethoxazole (TMP/SMX) (56.4%). Additionally, 36 (30.2%) isolates were multidrug-resistant and 13 of these 36 strains were identified as E. coli O25-ST131 clone by an allele-specific PCR-based assay. Phylogenetic analysis showed that 15 of 17 isolates with serotype O25:H4 belonged to group B2. Conclusions: This is the first report that establishes the presence in Mexico of the O25-ST131 clonal group of E. coli, which has been associated with multidrug-resistance and with high virulence potential. The spread of this clone in Mexico should be monitored closely. We found a correlation between serotype O25:H4 and multidrug resistance in UPEC strains. Our results indicate that the use of ampicillin, fluoroquinolones, and TMP/SMX should be reviewed when selecting empirical therapy for UTIs.

Antibiotic Resistance Pattern of Different Escherichia coli Phylogenetic Groups Isolated from Human Urinary Tract Infection and Avian Colibacillosis

“…The in vitro antibiotic susceptibility pattern of the isolates showed high resistance to commonly used antibiotics such as penicillin, erythromycin, nalidixic acid, cephalexin, amoxicillin, ampicillin and ciprofloxacin. Our findings are in agreement with those of previous studies [2, 4, 8, 17, 18]. This high degree of resistance could be explained by the fact that these drugs are easily available without physicians' prescriptions from pharmacy in developing countries.…”

Identification of Virulence Factors Genes inEscherichia coliIsolates from Women with Urinary Tract Infection in Mexico

“…Positive isolates to hlyA, cnf-1, and/or papC genes were susceptible to fluoroquinolones, results similar to those of Piatti et al [43]. Besides in Mexico, the previously reported E. coli resistance profile included ampicillin, piperacillin, fluoroquinolones, and trimethoprim/sulfamethoxazole which are considered to be first-line choices [13, 44, 45]. Additionally, serotype 025b-ST131 has been reported to be within the Mexican population which has been associated with plasmid mediated quinolone resistance [46].…”

“…The treatment of choice for ITU is in order of importance: fluoroquinolones (ciprofloxacin), the trimethoprim/sulfamethoxazole, cephalosporins, and penicillins (ampicillin) to which an increasingly developed resistance has been reported due mainly to the indiscriminated antibiotic use [13, 14]. In this work it is confirmed the resistance previously reported values for trimethoprim/sulfamethoxazole (56.1%) [14, 42]; for ciprofloxacin (62.3%), gatifloxacin, levofloxacin, and moxifloxacin, resistance was always above 50%.…”

“…UPEC strains can cause acute infections and recurrent infections that do not respond to common antimicrobial treatments. UTI treatment generally includes β -lactam antibiotics, fluoroquinolones, or trimethoprim/sulfamethoxazole [11–13] but may vary according to patient age, sex, Pathogen involved, course of disease, and the urinary tract anatomic area involved [5]. The increased resistance may be related to changes in the bacterial genome by mutation or acquisition by horizontal transfer of an extrachromosomal or chromosomal material [14–16].…”

Recombination Blurs Phylogenetic Groups Routine Assignment in Escherichia coli: Setting the Record Straight

“…Non-specific amplifications (as for an acetyl-hydrolase gene) using conventional Clermont's protocol have been reported for B1 isolates [22], but this protocol has also occasionally failed in the amplification of chu A and/or yja A [5], [23], [24], [25], [26]. In fact, in our series Clermont's multiplex PCR approach provides a worse assignment (14.0% misclassified) than Doumith's schema (1.7%), when C, E and F lineages were excluded.…”