Association of Fluoroquinolone Resistance, Virulence Genes, and IncF Plasmids with Extended-Spectrum-β-Lactamase-Producing Escherichia coli Sequence Type 131 (ST131) and ST405 Clonal Groups

Abstract

bThe global increase of extended-spectrum-␤-lactamase (ESBL)-producing Escherichia coli is associated with the specific clonal group sequence type 131 (ST131). In order to understand the successful spread of ESBL-producing E. coli clonal groups, we characterized fluoroquinolone resistance determinants, virulence genotypes, and plasmid replicons of ST131 and another global clonal group, ST405. We investigated 41 ST131-O25b, 26 ST131-O16, 41 ST405, and 41 other ST (OST) ESBL-producing isolates, which were collected at seven acute care hospitals in Japan. The detection of ESBL types, fluoroquinolone resistance-associated mutations (including quinolone resistance-determining regions [QRDRs]), virulence genotypes, plasmid replicon types, and IncF replicon sequence types was performed using PCR and sequencing. bla CTX-M , specifically bla CTX-M-14 , was the most common ESBL gene type among the four groups. Ciprofloxacin resistance was found in 90% of ST131-O25b, 19% of ST131-O16, 100% of ST405, and 54% of OST isolates. Multidrug resistance was more common in the ST405 group than in the ST131-O25 group (56% versus 32%; P ‫؍‬ 0.045). All ST131-O25b isolates except one had four characteristic mutations in QRDRs, but most of the isolates from the other three groups had three mutations in common. The ST131-O25b and ST405 groups had larger numbers of virulence genes than the OST group. All of the ST131-O25b and ST405 isolates and most of the ST131-O16 and OST isolates carried IncF replicons. The most prevalent IncF replicon sequence types differed between the four clonal groups. Both the ST131-O25b and ST405 clonal groups had a fluoroquinolone resistance mechanism in QRDRs, multidrug resistance, high virulence, and IncF plasmids, suggesting the potential for further global expansion and a need for measures against these clonal groups.T he global increase in extended-spectrum-␤-lactamase (ESBL)-producing Escherichia coli is closely related to a pandemic clonal group: CTX-M-type ESBL-producing E. coli with sequence type 131 belonging to the O25b serogroup and the B2 phylogenetic group (ST131-O25b) (1, 2). In addition to the ST131 clonal group, a CTX-M-producing ST405 clonal group belonging to phylogenetic group D (ST405) has also been detected worldwide (3-5). Our regional surveillance program in Japan previously demonstrated that not only the ST131-O25b group, but also the B2-ST131-O16 (ST131-O16) and ST405 clonal groups, contributed to the recent increase in prevalence of ESBL-producing E. coli (6).The success of the ST131-O25b clonal group has been explained by its acquisition of fluoroquinolone resistance and additional virulence factors (2). However, data for the ST131-O16 and ST405 clonal groups are lacking. Plasmids could be an important component of these clonal groups, because ESBL genes are generally located on plasmids (1). Clonal groups that were determined by multilocus sequence typing (MLST) have chromosomal genetic similarity. To characterize plasmids, replicon typing to assess the incompatibility group and seq...

Detection of <i>Escherichia coli</i> Producing CTX-M-1-Group Extended-Spectrum β-Lactamases from Pigs in Aichi Prefecture, Japan, between 2015 and 2016

“…In Japan, the isolation of E. coli isolates producing blaCTX-M-55 from livestock has been limited, and the isolation rates among healthy humans and in clinical settings have remained low to date (30,31). Moreover, IncF-group plasmids harboring blaCTX-M-14 and blaCTX-M-27 have been predominant among both healthy humans and clinical isolates (30,31). These findings suggest that pigs do not act as the main reservoir for ESBL producers found in humans.…”

“…All the E. coli isolates producing CTX-M-55 were susceptible to CIP and identified as ST117, but they were isolated from several different farms, suggesting that this bacterial strain spreads clonally among livestock in this area. In Japan, the isolation of E. coli isolates producing blaCTX-M-55 from livestock has been limited, and the isolation rates among healthy humans and in clinical settings have remained low to date (30,31). Moreover, IncF-group plasmids harboring blaCTX-M-14 and blaCTX-M-27 have been predominant among both healthy humans and clinical isolates (30,31).…”

Characteristics of ciprofloxacin-resistant Enterobacteriaceae isolates recovered from wastewater of an Algerian hospital

“…They are linked to phylogroups D, B1, and A, respectively [48], and are associated with ciprofloxacin resistance [49,50]. ST405 was associated with the spread of CTX-M-15 ESBL [48,50].…”

Rapid and Specific Detection, Molecular Epidemiology, and Experimental Virulence of the O16 Subgroup within Escherichia coli Sequence Type 131

“…Although ST131 classically exhibits serotype O25b:H4, multiple studies have documented a minor subset of ST131 isolates with serotype O16:H5 or O-type O16 (7)(8)(9)(10)(11)(12). This O16 subset within ST131 remains poorly characterized.…”

“…Among the extended-spectrum ␤-lactamase (ESBL)-producing E. coli isolates from Japan, the O16 ST131 subset was recently shown to represent a different Pasteur Institute sequence type (PST506) than classic O25b ST131 isolates (PST43) and to constitute a distinct phylogenetic clade (10,11). Additionally, compared with classic O25b ST131 clade members, the studied O16 ST131 clade members exhibited a relatively greater prevalence of CTX-M-14 over (ST131-associated) CTX-M-15, were less commonly fluoroquinolone resistant but more commonly trimethoprimsulfamethoxazole resistant, and escaped detection by a widely used PCR screening assay for ST131 that targets the O25b rfb (O lipopolysaccharide) allele and the housekeeping gene pabB (10,11).…”