Prevalence of Fluoroquinolone-Resistant Escherichia coli O25:H4-ST131 (CTX-M-15-Nonproducing) Strains Isolated in Japan
ABSTRACT Fluoroquinolone-resistant and extended-spectrum β-lactamase (ESBL)-carrying multidrug-resistant Escherichia coli have become severely problematic. In particular, a lineage of multilocus sequence-type ST131 which belongs to O25:H4 and carries ESBL CTX-M-15 has spread worldwide.
Fluoroquinolone-resistant E. coli strains were isolated from various clinical specimens in a commercial clinical laboratory in 2008 and 2009 in Hokkaido Prefecture, Japan.
Among 478 clinical isolates, 112 strains (23.4%) showed levofloxacin (LVX) resistance. About 80% of the fluoroquinolone-resistant strains (88 strains) showed common features, namely O25:H4-ST131, phylogenetic group B and the same mutation pattern in quinolone resistance-determining regions. Pulsed field gel electrophoresis patterns suggested numerous lineages of O25:H4-ST131. The fluoroquinolone-resistant strains, including strains of O25:H4-ST131 and other types, more frequently shared CTX-type ESBL genes than did fluoroquinolone-susceptible strains. The ESBL genes fell into the CTX-M-9 and CTX-M-2 groups. CTX-M-15 (CTX-M-1 group) was not found among any of the strains isolated in this study. Sitafloxacin showed markedly potent activity against E. coli isolates compared with LVX, ciprofloxacin and ulifloxacin.
The most prevalent fluoroquinolone-resistant strains of E. coli isolated in Hokkaido Prefecture, Japan, are O25:H4-ST131. However, similar to other areas of Japan, the ST131 clones represent distinct lineages from the general worldwide dispersal of multidrug-resistant clones which carry CTX-M-15.
SourceAvailable from: Jiun-Ling Wang[Show abstract] [Hide abstract]
ABSTRACT: Background To compare the epidemiological and clinical features and outcome in clonal group O25b/ST131 and non-clonal group O25b/ST131 in adult patients with non-extended-spectrum B-lactamase (ESBL)-producing Escherichia coli (E. coli) bacteraemia.Methods We collected 371 consecutive isolates with community-onset non-ESBL producing E. coli bloodstream infection in 2010 in a 1200-bed hospital in Taiwan. Twenty adult patients with clonal group O25b/ST131 and 40 patients with non-clonal group O25b/ST131 were compared.ResultClonal group O25b/ST131 accounted for 5.9% of total isolates. The underlying disease and healthcare-associated risk factors were similar in the case and control groups. Patients with the clonal group O25b/ST131 were less likely to have intra-abdominal infection (0% vs. 22.5%; p¿<¿0.05) than patients from the control group. The Day 30 mortality rate was similar in the case and control groups (15% vs. 12.5%).Conclusions Clonal group O25b/ST131 was found in both multidrug-resistant and susceptible E. coli strains, causing community-onset bloodstream infection. Although O25b/ST131 does not lead to a higher mortality than other isolates, choosing an appropriate antimicrobials in the empirical therapy of community-onset E. coli bacteraemia has become more challenging.BMC Infectious Diseases 11/2014; 14(1):579. DOI:10.1186/s12879-014-0579-z · 2.56 Impact Factor
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ABSTRACT: Background: Multidrug-resistant Escherichia coli, especially a lineage of O25b:H4-ST131, has increased and spread worldwide. The surveillance of cross-resistance of E. coli is necessary. Methods: Cross-resistance to fluoroquinolones (FQs) and aminoglycosides (AGs) was examined in E. coli isolated in Hokkaido Prefecture, Japan, between 2008 and 2009. Results: Gentamicin (GEN) resistance was more common in FQ-resistant isolates (30/112 strains; 26.8%) than in FQ-susceptible isolates (2/100 strains; 2%). The frequency of GEN resistance was similar in two groups of FQ-resistant strains, O25b:H4-ST131 genotype (22/87 strains; 25.3%) and a group of other FQ-resistant genotypes (8/25 strains; 32.0%). The main AG resistance gene was aac(3)-II (87.5% of GEN-resistant strains). The only amikacin-resistant strain which was FQ resistant carried the aac(6')-Ib-cr gene. CTX-M type extended-spectrum β-lactamase (ESBL) genes were also found in FQ-resistant strains at a high frequency. However, the number of strains with both ESBL and AG-modifying enzyme genes was relatively low (8 strains). Conclusion: All FQ-resistant strains, not only O25b:H4-ST131, appeared to preferentially acquire ESBL genes and/or genes encoding AG-modifying enzymes; however, the acquisitions of these genes seemed to occur independently. © 2014 S. Karger AG, Basel.Chemotherapy 05/2014; 59(5):379-384. DOI:10.1159/000361011 · 1.55 Impact Factor
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ABSTRACT: In 2008, a previously unknown Escherichia coli clonal group, sequence type 131 (ST131), was identified on three continents. Today, ST131 is the predominant E. coli lineage among extraintestinal pathogenic E. coli (ExPEC) isolates worldwide. Retrospective studies have suggested that it may originally have risen to prominence as early as 2003. Unlike other classical group B2 ExPEC isolates, ST131 isolates are commonly reported to produce extended-spectrum β-lactamases, such as CTX-M-15, and almost all are resistant to fluoroquinolones. Moreover, ST131 E. coli isolates are considered to be truly pathogenic, due to the spectrum of infections they cause in both community and hospital settings and the large number of virulence-associated genes they contain. ST131 isolates therefore seem to contradict the widely held view that high levels of antimicrobial resistance are necessarily associated with a fitness cost leading to a decrease in pathogenesis. Six years after the first description of E. coli ST131, this review outlines the principal traits of ST131 clonal group isolates, based on the growing body of published data, and highlights what is currently known and what we need to find out to provide public health authorities with better information to help combat ST131.Clinical Microbiology Reviews 07/2014; 27(3):543-574. DOI:10.1128/CMR.00125-13 · 16.00 Impact Factor