Escherichia coli Sequence Type 131 as a Prominent Cause of Antibiotic Resistance among Urinary Escherichia coli Isolates from Reproductive-Age Women

Abstract

dThe recent emergence of multidrug-resistant Escherichia coli sequence type 131 (ST131) has coincided with an increase in general antibiotic resistance of E. coli, suggesting that ST131 has a contributing role in resistance. However, there is little information about the contribution of ST131 to different clinical syndromes or the basis for its impressive emergence and epidemic spread. To investigate this, we studied 953 E. coli isolates from women of reproductive age in the central west region of New South Wales, Australia, including 623 urinary isolates from patients with cystitis (cystitis isolates) (n ‫؍‬ 322) or pyelonephritis (pyelonephritis isolates) (n ‫؍‬ 301) and 330 fecal isolates from healthy controls. The characteristics studied included ST131 clonal group status, resistance to different antibiotics, presence of virulence factor (VF) genes, and biofilm production. As expected, fecal isolates differed significantly from urinary (cystitis and pyelonephritis) isolates in most of the studied characteristics. Antibiotic resistance was significantly more common in ST131 than in non-ST131 isolates. Both antibiotic resistance and ST131 were more common in pyelonephritis than cystitis isolates and least so among fecal isolates. Within each source group, individual VF genes were more prevalent and VF scores were higher for ST131 than for non-ST131 isolates. For ST131 only, the prevalences of most individual VF genes and VF scores were the lowest in the fecal isolates, higher in the cystitis isolates, and highest in the pyelonephritis isolates. Biofilm production was strongly associated with ST131 status and antibiotic resistance. These results clarify the distribution of the ST131 clonal group and its epidemiological associations in our region and suggest that it exhibits both enhanced virulence and increased antibiotic resistance compared with those of other urinary tract infection (UTI) and fecal E. coli isolates from women of reproductive age. U rinary tract infections (UTIs) are among the most common bacterial infections in humans (1). They are usually caused by specialized strains of Escherichia coli termed uropathogenic E. coli (UPEC), which possess distinct virulence factors (VFs) that can allow them to invade and injure a host. The effective management of UPEC is needed to reduce the associated health care costs and social burden.Among urinary E. coli isolates, the prevalence of antibiotic resistance, especially to commonly used agents, such as fluoroquinolones (FQs), has increased substantially in recent years (2, 3, 4). However, although several studies have examined antibiotic resistance in different populations, most have not examined the related clinical and epidemiological associations. A better understanding of the microbiological basis for the emergence of antibiotic resistance among UPEC isolates is needed to guide the efforts that are aimed at interrupting this process.The recent emergence of multidrug-resistant E. coli sequence type 131 (ST131) has contributed to the rising prevalence of re...

Characteristics of Extended-Spectrum β-Lactamases-Producing <i>Escherichia coli</i> in Fecal Samples of Inpatients of Beijing Tongren Hospital

“…Similar results were also reported out of other countries, such as USA and Korea (22,23). ST131 is also the prominent ST in the Central West region of New South Wales, Australia (24). In the present study, the most common ST was ST38 (7.2%), followed by ST10 (6.0%), and ST131 (5.4%), and ST167 (5.4%).…”

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

“…This is consistent with the extensive virulence genotypes of clade members, which closely resemble those of conventional O25b ST131 isolates. These observations suggest substantial virulence potential for humans, which is supported by the epidemiological finding of Kudinha et al (8,9), in both women and men, of an ascending prevalence gradient for O16 ST131 isolates in relation to clinical severity, from fecal isolates from healthy hosts, through cystitis isolates, to pyelonephritis isolates, implying enhanced virulence for this clade relative to other E. coli.…”

“…We report here the first broad survey for this clade among unselected clinical isolates, as previous studies of this clade focused on ESBL-producing isolates from a single region (10)(11)(12), diverse convenience sample isolates (14,31), or all-comer isolates from a single locale (8,9,32). Our findings document that at multiple centers across the United States and Europe, the clade consistently accounts for approximately 1 to 5% of the E. coli clinical isolates overall and is associated with resistance to ampicillin, gentamicin, and TMP-SMZ but, especially in comparison with H30 ST131 isolates, with susceptibility to fluoroquinolones and extended-spectrum cephalosporins.…”

“…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.…”

Escherichia coli ST131, an Intriguing Clonal Group

“…E. coli ST131 strains are mostly of serotype O25:H4, with a specific O25 type, O25b. However, ST131 E. coli isolates of serotype O16:H5 have recently been identified in Japan, Denmark, Australia, Spain, Pakistan, and France (18)(19)(20)(21)(22)(23)(24). Moreover, some E. coli ST131 isolates have been shown to be nontypeable for O or H antigens (18,25).…”