Open AccessMolecular Epidemiology of Third-Generation-Cephalosporin-Resistant Enterobacteriaceae in Southeast Queensland, Australia
Author(s) -
Adam Stewart,
Erin P. Price,
Kim Schabacker,
Mehmet Birikmen,
Patrick N A Harris,
Keat Choong,
Shradha Subedi,
Derek S. Sarovich
Publication year - 2021
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.00130-21
Subject(s) - enterobacteriaceae , cephalosporin , microbiology and biotechnology , antibiotics , epidemiology , biology , 16s ribosomal rna , bacteria , medicine , gene , genetics , escherichia coli
Third-generation cephalosporin-resistant (3GC-R) Enterobacteriaceae represent a major threat to human health. Here, we captured 288 3GC-R Enterobacteriaceae clinical isolates from 264 patients presenting at a regional Australian hospital over a 14-month period. In addition to routine mass spectrometry and antibiotic sensitivity testing, isolates were examined using rapid (∼40-min) real-time PCR assays targeting the most common extended-spectrum β-lactamases (ESBLs; bla CTX-M-1 and bla CTX-M-9 groups, plus bla TEM , bla SHV , and an internal 16S rRNA gene control). AmpC CMY β-lactamase ( bla CMY ) prevalence was also examined. Escherichia coli (80.2%) and Klebsiella pneumoniae (17.0%) were dominant, with Klebsiella oxytoca , Klebsiella aerogenes , and Enterobacter cloacae infrequently identified. Ceftriaxone and cefoxitin resistance were identified in 97.0% and 24.5% of E. coli and K. pneumoniae isolates, respectively. Consistent with global findings in Enterobacteriaceae , most (98.3%) isolates harbored at least one β-lactamase gene, with 144 (50%) harboring bla CTX-M-1 group, 92 (31.9%) harboring bla CTX-M-9 group, 48 (16.7%) harboring bla SHV , 133 (46.2%) harboring bla TEM , and 34 (11.8%) harboring bla CMY genes. A subset of isolates ( n = 98) were subjected to whole-genome sequencing (WGS) to identify the presence of cryptic resistance determinants and to verify genotyping accuracy. WGS of β-lactamase-negative or carbapenem-resistant isolates identified uncommon ESBL and carbapenemase genes, including bla NDM and bla IMP , and confirmed all PCR-positive genotypes. We demonstrate that our PCR assays enable the rapid and cost-effective identification of ESBLs in the hospital setting, which has important infection control and therapeutic implications.