Outbreak of plasmid-mediated NDM-1-producing Klebsiella pneumoniae ST105 among neonatal patients in Yunnan, China

Annals of Clinical Microbiology and Antimicrobials, Feb 2016

Background In the past decade, the carbapenemase-producing Enterobacteriaceae (CPE) have been reported worldwide. Emergence of carbapenemase-producing strains among Enterobacteriaceae has been a challenge for treatment of clinical infection. The present study was undertaken to investigate the characteristics of carbapenem-resistant Klebsiella pneumoniae recovered from an outbreak that affected 17 neonatal patients in neonatal intensive care unit (NICU) of Kunming City Maternal and Child health Hospital, which is located in the Kunming city in far southwest of China. Methods Minimum inhibitory concentrations (MICs) for antimicrobial agents were determined according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI); Modified Hodge test and Carba-NP test were preformed to identified the phenotypes of carbapenemases producing; To determine whether carbapenem resistance was transferable, a conjugation experiment was carried out in mixed broth cultures; Resistant genes were detected by using PCR and sequencing; Plasmids were typed by PCR-based replicon typing method; Clone relationships were analyzed by using multilocus-sequence typing (MLST) and pulsed field gel electrophoresis (PFGE). Results Eighteen highly carbapenem-resistant Klebsiella pneumoniae were isolated from patients in NICU and one carbapenem-resistant K. pneumoniae isolate was detected in incubator water. All these isolates harbored bla NDM-1 . Moreover, other resistance genes, viz., bla IMP-4 , bla SHV-1 , bla TEM-1 , bla CTX-M-15 , qnrS1, qnrB4, and aacA4 were detected. The bla NDM-1 gene was located on a ca. 50 kb IncFI type plasmid. PFGE analysis showed that NDM-1-producing K. pneumoniae were clonally related and MLST assigned them to sequence type 105. Conclusions NDM-1 producing strains present in the hospital environment pose a potential risk and the incubator water may act as a diffusion reservoir of NDM-1- producing bacteria. Nosocomial surveillance system should play a more important role in the infection control to limit the spread of these pathogens.

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Outbreak of plasmid-mediated NDM-1-producing Klebsiella pneumoniae ST105 among neonatal patients in Yunnan, China

Zheng et al. Ann Clin Microbiol Antimicrob Outbreak of plasmid-mediated NDM-1-producing Klebsiella pneumoniae ST105 among neonatal patients in Yunnan, China Rui Zheng 0 1 2 Qian Zhang 4 Yidan Guo 3 Yue Feng 0 2 Li Liu 0 2 Amei Zhang 0 2 Yue Zhao 0 2 Xiaoyu Yang 0 2 Xueshan Xia 0 2 0 Faculty of Life Science and Technology, Kunming University of Science and Technology , No. 727 Jing Ming Road, Chenggong District, Kunming, Yunnan , China 1 Department of Clinical Laboratory, First People's Hospital of Yunnan province , Kunming, Yunnan , China 2 Faculty of Environmental Science and Engineering, Kunming University of Science and Technology , Kunming, Yunnan , China 3 Yunnan Center for Dis- ease Control and Prevention , Kunming, Yunnan , China 4 Department of Clinical Laboratory, Kunming City Maternal and Child health Hospital , Kunming, Yunnan , China Background: In the past decade, the carbapenemase-producing Enterobacteriaceae (CPE) have been reported worldwide. Emergence of carbapenemase-producing strains among Enterobacteriaceae has been a challenge for treatment of clinical infection. The present study was undertaken to investigate the characteristics of carbapenemresistant Klebsiella pneumoniae recovered from an outbreak that affected 17 neonatal patients in neonatal intensive care unit (NICU) of Kunming City Maternal and Child health Hospital, which is located in the Kunming city in far southwest of China. Methods: Minimum inhibitory concentrations (MICs) for antimicrobial agents were determined according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI); Modified Hodge test and Carba-NP test were preformed to identified the phenotypes of carbapenemases producing; To determine whether carbapenem resistance was transferable, a conjugation experiment was carried out in mixed broth cultures; Resistant genes were detected by using PCR and sequencing; Plasmids were typed by PCR-based replicon typing method; Clone relationships were analyzed by using multilocus-sequence typing (MLST) and pulsed field gel electrophoresis (PFGE). Results: Eighteen highly carbapenem-resistant Klebsiella pneumoniae were isolated from patients in NICU and one carbapenem-resistant K. pneumoniae isolate was detected in incubator water. All these isolates harbored blaNDM-1. Moreover, other resistance genes, viz., blaIMP-4, blaSHV-1, blaTEM-1, blaCTX-M-15, qnrS1, qnrB4, and aacA4 were detected. The blaNDM-1 gene was located on a ca. 50 kb IncFI type plasmid. PFGE analysis showed that NDM-1-producing K. pneumoniae were clonally related and MLST assigned them to sequence type 105. Conclusions: NDM-1 producing strains present in the hospital environment pose a potential risk and the incubator water may act as a diffusion reservoir of NDM-1- producing bacteria. Nosocomial surveillance system should play a more important role in the infection control to limit the spread of these pathogens. CPE; NDM-1; ST105; China Background Gram-negative bacilli are the most important cause of healthcare associated infections [ 1 ]. Among these, Enterobacteriaceae continue to be an important cause of such infections [ 2 ], particularly the carbapenemaseproducing Enterobacteriaceae (CPE) in developing countries, such as China [ 3 ]. In the past decade, the CPEs have been reported worldwide, including KPC-, GES-, VIM-, IMP-, GIM-, NDM- and OXA- types [ 4 ]. Among them, the NDM-type carbapenemase is a novel metalo-betalactamase that was identified for the first time in 2008 [ 5 ]. NDM-1 carbapenemase belongs to class B of Ambler β-lactamases, and efficiently hydrolyses a broad range of β-lactams, including penicillins, cephalosporins, and carbapenems, except for aztreonam. Up to this day, the emergence of carbapenemase-producing strains among Enterobacteriaceae has been a challenge for treatment of clinical infection [ 6 ]. Plasmid-mediated drug resistance is one of the most serious problems in the treatment of infectious diseases due to the horizontal transfer of plasmids account for the dissemination of resistance genes and the emergence of drug resistant strains [ 7, 8 ]. Carbapenemase-producing strains are most often associated with many non-βlactam-resistance genes, because of their locations on plasmids [9], which made therapeutic options for infections were very limited. Klebsiella pneumoniae was a leading cause of nosocomial infections and spread rapidly in health care settings due to efficiency of colonization and rapid development of resistance to a wide range of antimicrobials [ 10 ]. Recently, K. pneumoniae harboring blaNDM-1 were emergencing in China, which should pay great attention [ 11, 12 ]. Therefore, investigation of the molecular characteristics of NDM-1-producing K. pneumoniae is critical. Here, we identified 19 K. pneumoniae harboring blaNDM-1, the transmission of these NDM-1-producing K. pneumoniae among neonatal patients at Kunming City Maternal and Child health Hospital was delineated (...truncated)


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Rui Zheng, Qian Zhang, Yidan Guo, Yue Feng, Li Liu, Amei Zhang, Yue Zhao, Xiaoyu Yang, Xueshan Xia. Outbreak of plasmid-mediated NDM-1-producing Klebsiella pneumoniae ST105 among neonatal patients in Yunnan, China, Annals of Clinical Microbiology and Antimicrobials, 2016, pp. 10, 15, DOI: 10.1186/s12941-016-0124-6