Whole genome analysis of cephalosporin-resistant Escherichia coli from bloodstream infections in Australia, New Zealand and Singapore: high prevalence of CMY-2 producers and ST131 carrying blaCTX-M-15 and blaCTX-M-27.
J Antimicrob Chemother
; 73(3): 634-642, 2018 03 01.
Article
in En
| MEDLINE
| ID: mdl-29253152
ABSTRACT
Objectives:
To characterize MDR Escherichia coli from bloodstream infections (BSIs) in Australia, New Zealand and Singapore.Methods:
We collected third-generation cephalosporin-resistant (3GC-R) E. coli from blood cultures in patients enrolled in a randomized controlled trial from February 2014 to August 2015. WGS was used to characterize antibiotic resistance genes, MLST, plasmids and phylogenetic relationships. Antibiotic susceptibility was determined using disc diffusion and Etest.Results:
A total of 70 3GC-R E. coli were included, of which the majority were ST131 (61.4%). BSI was most frequently from a urinary source (69.6%), community associated (62.9%) and in older patients (median age 71 years). The median Pitt score was 1 and ICU admission was infrequent (3.1%). ST131 possessed more acquired resistance genes than non-ST131 (P = 0.003). Clade C1/C2 ST131 predominated (30.2% and 53.5% of ST131, respectively) and these were all ciprofloxacin resistant. All clade A ST131 (n = 6) were community associated. The predominant ESBL types were blaCTX-M (80.0%) and were strongly associated with ST131 (95% carried blaCTX-M), with the majority blaCTX-M-15. Clade C1 was associated with blaCTX-M-14 and blaCTX-M-27, whereas blaCTX-M-15 predominated in clade C2. Plasmid-mediated AmpC genes (mainly blaCMY-2) were frequent (17.1%) but were more common in non-ST131 (P < 0.001) isolates from Singapore and Brisbane. Two strains carried both blaCMY-2 and blaCTX-M. The majority of plasmid replicon types were IncF.Conclusions:
In a prospective collection of 3GC-R E. coli causing BSI, community-associated Clade C1/C2 ST131 predominate in association with blaCTX-M ESBLs, although a significant proportion of non-ST131 strains carried blaCMY-2.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Beta-Lactamases
/
Cephalosporins
/
Bacteremia
/
Escherichia coli
/
Escherichia coli Infections
Type of study:
Clinical_trials
/
Observational_studies
/
Prevalence_studies
/
Risk_factors_studies
Limits:
Aged
/
Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
Asia
/
Oceania
Language:
En
Journal:
J Antimicrob Chemother
Year:
2018
Document type:
Article
Affiliation country:
Australia