Molecular Epidemiology of Third-Generation-Cephalosporin-Resistant Enterobacteriaceae in Southeast Queensland, Australia.
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.
['Stewart|A G|AG|', 'Price|E P|EP|0000-0002-1079-4882', 'Schabacker|K|K|', 'Birikmen|M|M|', 'Harris|P N A|PNA|0000-0002-2895-0345', 'Choong|K|K|', 'Subedi|S|S|', 'Sarovich|D S|DS|0000-0002-6944-3980']
D000900:Anti-Bacterial Agents D001315:Australia D002440:Cefoxitin D004755:Enterobacteriaceae D004756:Enterobacteriaceae Infections D004926:Escherichia coli D006801:Humans D008826:Microbial Sensitivity Tests D017720:Molecular Epidemiology D011793:Queensland D012336:RNA, Ribosomal, 16S D001618:beta-Lactamases
Enterobacteriaceae antibiotic real-time PCR ESBL resistance whole-genome sequencing antimicrobial cephalosporin diagnostics