Abstract
BackgroundThe rates of multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR) isolates among Enterobacteriaceae isolates, particularly Klebsiella pneumoniae, have risen substantially worldwide.Methodology/Principal FindingsTo better understand the molecular mechanisms of drug resistance in K. pneumoniae, we analyzed the drug resistance determinants for K. pneumoniae isolates collected from the 306 Hospital, a tertiary-care hospital in Beijing, China, for the period of September 1, 2010-October 31, 2011. Drug susceptibility testing, PCR amplification and sequencing of the drug resistance determinants were performed. Conjugation experiments were conducted to examine the natural ability of drug resistance to disseminate among Enterobacteriaceae strains using a sodium azide-resistant Escherichia coli J53 strain as a recipient. Among the 223 consecutive non-repetitive K. pneumoniae isolates included in this study, 101 (45.3%) were extended-spectrum beta-lactamases (ESBLs) positive. The rates of MDR, XDR, and PDR isolates were 61.4% (n = 137), 22.0% (n = 49), and 1.8% (n = 4), respectively. Among the tested drug resistance-associated genes, the following ones were detected at relatively high rates bla CTX-M-10 (80, 35.9%), aacC2 (73, 32.7%), dhfr (62, 27.8%), qnrS (58, 26.0%), aacA4 (57, 25.6%), aadA1 (56, 25.1%). Results from conjugation experiments indicate that many of the drug resistance genes were transmissible.Conclusions/SignificanceOur data give a “snapshot” of the complex genetic background responsible for drug resistance in K. pneumoniae in China and demonstrate that a high degree of awareness and monitoring of those drug resistance determinants are urgently needed in order to better control the emergence and transmission of drug-resistant K. pneumoniae isolates in hospital settings.
Highlights
The emergence and rapid spread of drug-resistant Klebsiella pneumoniae isolates is becoming a serious antibiotic management problem and causing a great concern worldwide [1,2,3,4,5,6]
In a study based on the Tigecycline Evaluation and Surveillance Trial (TEST) global surveillance database, the rate of extended-spectrum beta-lactamases (ESBLs) production was highest among the K. pneumoniae isolates collected in Latin America, followed by Asia/Pacific Rim, Europe, and North America (44.0%, 22.4%, 13.3% and 7.5%, respectively) [23]
Demographic and Clinical Characteristics of the Patients From September 1, 2010 to October 31, 2011, a total of 223 non-repetitive patients at the 306 Hospital who had K. pneumoniae isolates were subjected to Drug susceptibility testing (DST) using 18 antibiotics
Summary
The emergence and rapid spread of drug-resistant Klebsiella pneumoniae isolates is becoming a serious antibiotic management problem and causing a great concern worldwide [1,2,3,4,5,6]. Since the production of newer betalactamases is frequently accompanied by broad-spectrum resistance, the ESBL positivity together with the existence of newer beta-lactamases should be monitored closely as the emergence of those highly drug-resistant K. pneumoniae strains will pose a serious impact on the remaining therapeutic options [19,20,21,22]. In a study based on the Tigecycline Evaluation and Surveillance Trial (TEST) global surveillance database, the rate of ESBL production was highest among the K. pneumoniae isolates collected in Latin America, followed by Asia/Pacific Rim, Europe, and North America (44.0%, 22.4%, 13.3% and 7.5%, respectively) [23]. The rates of multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR) isolates among Enterobacteriaceae isolates, Klebsiella pneumoniae, have risen substantially worldwide
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