Bacteremia Caused by Extended-Spectrum-β-Lactamase-Producing Escherichia coli Sequence Type ST131 and Non-ST131 Clones: Comparison of Demographic Data, Clinical Features, and Mortality

Abstract

Escherichia coli producing the highly virulent, multidrug-resistant, CTX-M-15 extended-spectrum ␤-lactamase (ESBL), sequence type 131 (ST131), has emerged on three continents since the late 2000s. We described the molecular epidemiology, clinical features, and outcome of ESBL-producing E. coli bacteremia in Taiwan Independent risk factors predicting mortality at day 28 included malignancy, shock, and hospital-acquired bacteremia. In ESBLproducing E. coli bloodstream infections, the ST131 clone was not associated with health-care-associated risk factors, such as urinary catheter use or antibiotic exposure. Although highly virulent and multidrug resistant, the ST131 clone was not associated with higher mortality than non-ST131 clones. Between 2000 and 2006, Escherichia coli clone O25:H4-ST131, which produces CTX-M-15 extended-spectrum ␤-lactamase (ESBL), was identified on three continents and later found to be widespread in Europe, Australia, and the United States of America (6,11,13,17,19,22,24). The sequence type 131 (ST131) strain was associated with high, homogenous, extraintestinal virulence and multidrug resistance (6,11,13,17,19,22,24). Virulence gene analysis indicated that clone ST131 strains were more likely than non-ST131 strains to possess traT, iutA, iha, ompT, fimH, malX, fyuA, kpsM, or sat genes (6, 11, 13, 17, 19, 22, 24). Pulsotype analysis revealed that CTX-M-15 ST131 clones were usually approximately 85% similar (6,11,13,17,19,22,24).According to the published literature, most ST131 clones have been identified as a result of urine culture surveillance, and a few have been isolated from individuals with bacteremia. ST131 clones have been observed in the community, hospitals, and nursing homes (6,11,13,17,19,22,24) as well as in companion animals and poultry (23). In a French study, ST131 isolates were found in 7% of fecal E. coli isolates from independent healthy subjects and were unaccompanied by the CTX-M enzyme (14). However, several case reports have shown that ST131 clones can present in cases of severe infection, such as pyomyositis, emphysematous pyelonephritis, and other life-threatening infections (10,18,28). Only two cohorts with ST131 ESBL E. coli bacteremia have been reported in the literature. In these two ESBL E. coli bacteremia series, ST131 was found in 34% of isolates in the Netherlands (27) and 31.3% of isolates in Calgary, Canada (21). In Calgary's ESBL E. coli bacteremia cohort (21), ST131 isolates producing CTX-M-15 became predominant from 2005 to 2007 and were associated with community-onset infection and urosepsis. However, the detailed demographic features, clinical syndromes, and outcomes in these two cohorts of patients with ESBL E. coli bacteremia in clone ST131 are lacking. In previous risk factor analyses, ESBL E. coli infection was more closely associated with antibiotic use, comorbidity, and urinary catheter use than non-ESBL E. coli infection (2, 9, 15). We did not know whether ST131 clones were associated with the same risk factors as previous traditional ESBL E...

Four Main Virotypes among Extended-Spectrum-β-Lactamase-Producing Isolates of Escherichia coli O25b:H4-B2-ST131: Bacterial, Epidemiological, and Clinical Characteristics

“…Although the O25b-ST131 isolates were associated with bacteremia in univariate analyses, this association was not significant when age and acquisition type were considered in multivariate analysis. Chung et al (40) found that patients with clone ST131 were more likely to have secondary bacteremia than those with non-ST131 isolates. As has been found in other studies (39-41), we did not find that O25b-ST131 isolates were associated with increased mortality.…”

Escherichia coli ST131, an Intriguing Clonal Group

“…The study designs were different, with a case-control design used in France (case, a patient with a CTX-M-producing ST131 E. coli isolate from any clinical sample; control, a patient with an ESBLproducing non-ST131 E. coli clinical isolate from any sample) and in Spain (case 1, a patient with a non-ESBL-producing ST131 E. coli clinical isolate; control 1, a patient with a non-ESBL-producing non-ST131 E. coli clinical isolate; case 2, a patient with an ESBL-producing ST131 E. coli isolate from any clinical sample; and control 2, a patient with an ESBL-producing non-ST131 E. coli clinical isolate from any sample) (54,208). In contrast, cohort studies were carried out in Taiwan (cases, patients with an ESBLproducing ST131 E. coli isolate causing bacteremia; controls, patients with an ESBL-producing non-ST131 E. coli isolate causing bacteremia) and the United States (cases, patients with an E. coli ST131 isolate from any sample; controls, patients with a non-ST131 E. coli isolate from any sample) (156,162). The number of E. coli isolates producing ESBL was not mentioned in the American study.…”

“…Four studies to date have investigated the factors associated with clinical isolates of E. coli ST131 (54,156,162,208). These studies were performed in different countries (Taiwan, one hospital be- .…”

“…These studies also differed in terms of the methods used to identify the ST131 clonal group among E. coli isolates. The MLST method was applied to all E. coli isolates included in the Taiwanese and French studies (162,208). Screening methods were carried out in both the Spanish study (PCR for 025b rfb and allele 3 of the pabB gene in B2 group isolates) and in the American study (detection of single-nucleotide polymorphisms of the mdh and gyrB genes associated with the two-locus clonal typing strategy based on the sequencing of the fumC and fimH genes in B2 group E. coli isolates) (54,156).…”

Molecular Epidemiological Characteristics of Klebsiella pneumoniae Associated with Bacteremia among Patients with Pneumonia

“…In order to predict and evaluate bacterial pathogenicity, it is important to first determine the genetic background of the bacteria causing severe infections. Recently, using MLST, some studies investigated the relationship between the pathogenicity of microbes and the specific multilocus sequence types (STs) in Escherichia coli and Streptococcus pneumoniae (13,14). However, research on this relationship among K. pneumoniae infections is limited (15).…”