<p>Resistance mechanisms and molecular epidemiology of carbapenem-nonsusceptible <em>Escherichia coli</em> in Taiwan, 2012-2015</p>

Abstract

Purpose This study aimed to investigate the resistance mechanisms and molecular epidemiology of carbapenem-nonsusceptible Escherichia coli (CnsEC) in Taiwan. Patients and methods From 2012 to 2015, 237 E. coli isolates with minimum inhibitory concentrations of imipenem or meropenem >1 μg/mL were collected in a nationwide surveillance and subjected to polymerase chain reaction (PCR) for carbapenemase, AmpC-type β-lactamase, and extended spectrum β-lactamase (ESBL) genes. We evaluated outer membrane proteins (OmpF and OmpC) loss and conducted multilocus sequence typing and pulsed-field gel electrophoresis (PFGE). Isolates that were resistant to all carbapenems were designated as pan-carbapenem-resistant E. coli (pCREC) in this study. Results The predominant resistance mechanism of CnsEC in Taiwan was the CMY-2 β-lactamase in combination with OmpF and OmpC loss. Sequence type 131 was the most prevalent type (29.2%). Among 237 CnsEC isolates, 106 (44.7%) isolates were pCREC and 18 (7.59%) produced carbapenemase. The prevalence of carbapenemases increased from 6% in 2012 to 11.36% in 2015. Various carbapenemases including KPC-2, IMP-8, NDM-1, NDM-5, VIM-1, OXA-48, and OXA-181 were identified, with NDM-1 being the most common (38.9%) carbapenemase. Comparison between pCREC and non-pCREC among the non-carbapenemase-producing CnsEC isolates revealed SHV, CMY, co-carriage of SHV and CTX-M and concurrent loss of both OmpF and OmpC were more commonly detected in the pCREC group. PFGE revealed no nationwide clonal spread of carbapenemase-producing E. coli . Conclusion NDM-1 was the most common carbapenemase and combination of CMY-2 and concurrent OmpF and OmpC porin loss was the most prevalent resistance mechanism in CnsEC in Taiwan.

<p>Molecular Mechanisms and Epidemiology of Carbapenem-Resistant <em>Escherichia coli</em> Isolated from Chinese Patients During 2002–2017</p>

“…Notably, in previous studies in China, a few strains of E. coli with KPC-2 were detected. 36 However, in our study, 22.4% (13/58) of the strains were detected with KPC-2. This finding suggested that more attention should be paid to the spread of KPC-2 in this region.…”

In vitro activity of ceftazidime–avibactam and comparators against Gram-negative bacterial isolates collected in the Asia–Pacific region as part of the INFORM program (2015–2017)

“…Similar trends were observed among K. pneumoniae isolates, although there were relatively low isolate numbers in the resistant subsets for this species. Studies of antimicrobial resistance in South Korea and Taiwan, on isolates collected between 2012 and 2017, have reported the rates of amikacin resistance to be < 10% among E. coli and K. pneumoniae isolates [20][21][22], and among carbapenemnonsusceptible E. coli isolates (Taiwan only) [23].…”

“…For P. aeruginosa isolates in the current study, the MDR subset accounted for 23 [11,26]. Each study used the MDR definition proposed by Magiorakos et al [18]; however, variations in the participating countries and time periods for each study may account for the differences in the overall regional rates.…”

The Current Burden of Carbapenemases: Review of Significant Properties and Dissemination among Gram-Negative Bacteria

“…Among the different efflux systems, the AcrAB-TolC RND system is the most common, and has been identified among carbapenem-resistant E. cloacae [189], E. coli [190], and K. pneumoniae [191]. Alteration of porin synthesis, such as deficiency of OmpK-35 and 36 in K. pneumoniae [192,193], and loss of OmpF and OmpC in E. coli [194], have been described in AmpCand carbapenemase-producing Enterobacteriaceae. Studies suggest that strains with porins mutated or downregulated typically do not have the potential for mobilization into community settings but may carry the risk of possible local proliferation within hospitals [188].…”