Distribution of virulence determinants among Escherichia coli ST131 and its H30/H30-Rx subclones in Turkey

Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading pathogen in urinary tract infection. In recent years multidrug-resistant B2-ST131 E. coli clonal group has disseminated worldwide. The ST131 and its subclones H30 and H30-Rx have been identified only in a few studies from Turkey. The aim of this study is to investigate the presence of ST131 and its subclones and to analyze their adhesin virulence genes and antimicrobial resistance. A total of 250 urinary ExPEC isolates were included in the study. Resistance rates of 16 antimicrobial agents were determined by disk-diffusion. Multidrug-resistance and ESBL production were analyzed. Altogether 8 adhesin genes were investigated namely, papAH, fimH, sfa/focDE, focG, afa/draBC, iha, bmaE and gafD. A total of 39 ST131 isolate were determined and 33 (84.6%) were multidrug-resistant. ESBL production was detected in 34 (87.2%) ST131 and 61 (28.9%) of non-ST131 strains. In our study, we found a strong correlation between ST131 strains and fimH, iha, afa/draBC, papAH virulence determinants. Twenty-nine (85.3%) of 34 ST131-O25b-H30 isolates were identified as H30-Rx. All the papAH gene positive isolates were identified within ST131-O25b-H30-Rx lineage. Non-H30-Rx isolates within H30 isolates were identified as pattern 2. Almost 16% of the isolates were identified as ST131 regardless of clinical syndrome and approximately 34% of the multidrug-resistant isolates were H30-Rx subclone. We report H30-Rx as the dominant subclone of ST131 in our study. Imipenem, fosfomycin and nitrofurantoin proved to be the most effective agents according to antibiotic resistance patterns of both ST131 and non-ST131 E. coli strains.

The clinical impact of ST131 H30-Rx subclone in urinary tract infections due to multidrug-resistant Escherichia coli

In this study, risk factors for ST131 H30 and H30-Rx subclones among urinary tract infections (UTIs) caused by multidrug-resistant (MDR) Escherichia coli were described. Urine samples were collected from consecutive outpatients registered to the outpatient clinics of Başkent University Hospital (Ankara, Turkey) with complaints of acute cystitis in 2011. A total of 107 MDR E. coli isolates were included in the study. Of the 107 isolates studied, 26 (24.3%) were typed as ST131 clone. Extended-spectrum β-lactamase (ESBL)-producers accounted for 59 (55.1%) of the 107 isolates. Among the 59 ESBL-positive isolates, 18 (31%) were found to belong to the ST131 clone. Of the 18 ESBL-positive ST131 isolates, 17 (94%) were defined as H30 subclone, among which 16 (94%) represented the H30-Rx subclone. Among the 48 ESBL-negative isolates, 8 (17%) ST131 isolates were detected, 7 (88%) of which belonged to H30 subclone; 5 (71%) of the H30 subclone isolates were classified under H30-Rx subclone. In multivariate analysis, hospitalisation within last year was the only host risk factor associated with MDR E. coli ST131 H30-Rx subclone UTI (OR=3.5, 95% CI 1.04-12.17; P=0.042). CTX-M-15 production was found to be highly associated with the presence of ST131 H30-Rx subclone (OR=4.8, 95% CI 1.54-15.32; P=0.007). In conclusion, urinary MDR E. coli ST131 H30-Rx subclone was found to be important in the dissemination of MDR UTIs in the community. Approximately 20% of the MDR isolates were H30-Rx subclone. Infection with this subclone was found to be healthcare-associated.