Prevalence of CTX-M extended-spectrum beta-lactamases and sequence type 131 in Korean blood, urine, and rectal Escherichia coli isolates

Extended-Spectrum β-Lactamase and AmpC β-Lactamase-Producing Escherichia coli Isolates from Chickens Raised in Small Flocks in Ontario, Canada

Food-producing animals are recognized to play a role in the epidemiology of antimicrobial resistance in Canada. However, the presence of resistant organisms in particular groups of animals, such as chickens raised in small-holder flocks, has not been studied. The purpose of this study was, therefore, to identify and characterize Escherichia coli possessing broad-spectrum β-lactamase genes among a collection of third-generation cephalosporin-resistant isolates recovered from 205 small flocks in southern Ontario. Extended-spectrum β-lactamase (ESBL; CTX-M-1) positive strains were isolated from 26 out of 205 flocks (12.7%), whereas 39 strains possessing AmpC (CMY-2) were grown from 31 out of 205 flocks (15.1%). Pulsed-field gel electrophoresis (PFGE) revealed that the isolates were genetically heterogeneous. Further testing by multi-locus sequence typing confirmed that none of the PFGE-defined clusters belonged to ST131. Our results suggest that the dissemination of this resistance in bacteria isolated from chickens in small-holder flocks may be associated with the spread of plasmids rather than particular E. coli clones and that these isolates do not possess the ESBL types most commonly associated with human infections (CTX-M-15).

High Prevalence of Multidrug-Resistant Escherichia coli in Urine Samples from Inpatients and Outpatients at a Tertiary Care Hospital in Sétif, Algeria

The worldwide dissemination of multidrug-resistant (MDR) Enterobacteriaceae is a major public health issue. The aim of this study was to investigate the prevalence of MDR Escherichia coli (MDR-EC) isolates, in inpatients/outpatients with urinary tract infections at Sétif University Hospital (Algeria). Bacterial cultures were obtained from 426 of the 3,944 urine samples collected from January 2015 to February 2017. Among these cultures, 215 E. coli isolates were identified by mass spectrometry, and 38 (17.7%) were MDR-EC (disk diffusion method): 36 produced only extended-spectrum β-lactamases (ESBL), one ESBL and a carbapenemase, and one only a cephalosporinase (double-disk synergy test). Multiplex PCR and sequencing analyses showed that 37 ESBL-producing isolates harbored genes encoding CTX-M enzymes (CTX-M-15 in 33 isolates, 89.19%; and CTX-M-14 group in four isolates, 10.81%). One CTX-M-15-producing isolate co-expressed also an OXA-48-like carbapenemase. Phylogenetic group analysis of the 37 ESBL-producing and 178 non-ESBL-producing isolates indicated that the most common phylogenetic group was B2 (54.05% of ESBL-producing and 48.31% of non-ESBL-producing isolates), followed by A and D for ESBL-, and by B1, A, and F for non-ESBL-producing isolates. This is the first report highlighting the presence of MDR-EC isolates that produce both CTX-M and OXA-48-like enzymes in Sétif, Algeria.

Antibiotic-resistant clones in Gram-negative pathogens: presence of global clones in Korea

Antibiotic resistance is a global concern in public health. Antibiotic-resistant clones can spread nationally, internationally, and globally. This review considers representative antibiotic-resistant Gram-negative bacterial clones-CTX-M- 15-producing ST131 in Escherichia coli, extended-spectrum ß-lactamase-producing ST11 and KPC-producing ST258 in Klebsiella pneumoniae, IMP-6-producing, carbapenem-resistant ST235 in Pseudomonas aeruginosa, and OXA-23-producing global clone 2 in Acinetobacter baumannii-that have disseminated worldwide, including in Korea. The findings highlight the urgency for systematic monitoring and international cooperation to suppress the emergence and propagation of antibiotic resistance.

Association of Escherichia coli ST131 lineage with risk of urinary tract infection recurrence among young women

OBJECTIVES

The aim of this study was to test the hypothesis that urinary tract infections (UTIs) caused by Escherichia coli of the sequence type 131 (ST131) lineage are more likely to recur than UTIs caused by other E. coli lineages.

METHODS

Isolates from 221 young women with UTI caused by E. coli participating in a randomised controlled trial were used. Participants were followed for 6 months or until UTI recurrence.

RESULTS

Sequence type was not associated with risk of recurrence. Isolates in the ST131 lineage were more resistant than other STs to quinolones (6.2% vs. 1.3%) but not trimethoprim/sulfamethoxazole (15.4% vs. 15.0%).

CONCLUSIONS

These results do not support an increased risk of recurrent UTI among otherwise healthy women with UTI caused by E. coli ST131.

Extended-spectrum β-lactamase-producing Escherichia coli bacteremia: Comparison of pediatric and adult populations

BACKGROUND/PURPOSE

The prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is increasing worldwide. This study investigated the clinical features and bacteriology of pediatric patients with ESBL-producing E. coli bacteremia and compared their characteristics with those of adult patients.

METHODS

Clinical and laboratory data from all of the 41 patients aged ≤18 years diagnosed with E. coli bacteremia were collected over 5 years. Patients aged >18 years diagnosed with E. coli bacteremia, matched 1:1 for calendar time, were enrolled as the adult group. All E. coli isolates were tested for their blaCTX-M group and sequence type 131 (ST131). A novel seven-single nucleotide polymorphism-based clonotyping test was applied to detect the septatypes of each isolate.

RESULTS

In the adult group, patients with ESBL-producing E. coli bacteremia had more previous hospitalizations and antimicrobial agent use than did those with non-ESBL-producing E. coli bacteremia, but these differences were not found in pediatric group. In the pediatric group, the proportion of isolates producing CTX-M group 9 was higher than that in the adult group (85.7% vs. 42.9%; p < 0.05). Among both groups, there were more E. coli ST131 in ESBL isolates in than there were non-ESBL isolates. The distribution of septatypes was more homogenous in ESBL-producing E. coli among the pediatric patients than among the adult patients.

CONCLUSION

ST131 was the major clone causing E. coli bacteremia in both pediatric and adult populations. The pediatric population demonstrated a higher number of isolates producing CTX-M group 9 with more homogenous septatypes compared with the adult population.