Abstract
BackgroundThe aim of this study was to elucidate the molecular epidemiology of carbapenem non-susceptible Enterobacteriaceae(CNSE) isolated in the Eastern region of Heilongjiang Province, China, and the mechanism of carbapenem resistance.MethodsA total of 53 CNSE isolates were collected in a grade-3 hospital in Heilongjiang province. Sensitivity to antibiotics was determined using the VITEK-2 Compact automatic system. The modified Hodge test (MHT) and modified carbapenem inactivation test (mCIM) were performed for phenotypic identification. Beta-lactamases gene were detected by Polymerase chain reaction(PCR) and DNA sequencing. The transfer of blaNDM and blaKPC was investigated through conjugation experiment. The clinical data of patients were retrospectively reviewed. Homology of Carbapenem-resistant Klebsiella pneumoniae(CRKP) was conducted by multilocus sequence typing (MLST).ResultsCNSE were highly resistant to the majority of antimicrobial agents. The resistance rate was 100% for first, third, fourth generation cephalosporins and enzyme inhibitor compounds. Gentamicin and tobramycin recorded a resistance rate higher than 80%. Less than 30% resistance was detected for amikacin and levofloxacin. Among CNSE 52(98.1%) and 48(90.6%) of CNSE were positive for mCIM and MHT respectively. There were 42 positive blaKPC genes, three blaNDM-1 genes, three blaNDM-5 genes, one blaNDM-7 gene, and six blaIMP-4 genes. Most isolates harbored multiple drug resistance gene, especially as related to extended-spectrum-β-lactamases, blaSHV, blaTEM and blaCTX-M-15 genes.The resistant gene was transferred into recipient Escherichia coli J53 through conjugation in 21.3% (10/47) of the strains. MLST revealed that ST76 (n = 36) was the most predominant clone, followed by ST896, ST323 and ST11. A new one ST 2946 was identity by this study.ConclusionThe carbapenem resistance phenomenon is alarming and blaKPC-2 is the main resistant gene of CNSE in our hospital. This is the first report of an outbreak caused by blaKPC-2 positive K. pneumoniae ST76 in the Eastern region of Heilongjiang Province, China. Relevant departments should implement infection control and prevention measures to avoid further dissemination of the multi drug-resistant bacteria (MDR).
Highlights
The aim of this study was to elucidate the molecular epidemiology of carbapenem non-susceptible Enterobacteriaceae(CNSE) isolated in the Eastern region of Heilongjiang Province, China, and the mechanism of carbapenem resistance
It has been reported that the high colonization rate of Klebsiella pneumoniae Carbapenemase(KPC)producing Klebsiella pneumoniae in patients with ICU is related to the number of comorbidities, administration of carbapenems, β-lactams/lactamase inhibitors, and the time of previous ICU admission [2]
We demonstrated that the sequence type ST76 was the predominant type among Carbapenemresistant Klebsiella pneumoniae (CRKP) isolates which are blaKPC-2 positive in Heilongjiang Province
Summary
The aim of this study was to elucidate the molecular epidemiology of carbapenem non-susceptible Enterobacteriaceae(CNSE) isolated in the Eastern region of Heilongjiang Province, China, and the mechanism of carbapenem resistance. It has been reported that the high colonization rate of Klebsiella pneumoniae Carbapenemase(KPC)producing Klebsiella pneumoniae in patients with ICU is related to the number of comorbidities, administration of carbapenems, β-lactams/lactamase inhibitors, and the time of previous ICU admission [2]. The main mechanisms of carbapenem resistance among Enterobacteriaceae are the production of carbapenemases such as KPC and New Delhi metalloβ-lactamase (NDM), extended spectrum β-lactamase (ESBL) or AmpC β-lactamases(AmpC) enzymes that are accompanied more rarely with loss of outer membrane proteins. These resistant genes are often located on plasmids. We investigated the prevalence and resistance characteristics of CNSE in the largest university hospital in the eastern region of Heilongjiang Province, focusing on the resistance mechanism and epidemiologic characteristics
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