Suchergebnisse

Kaiying Wang,1,2,* Peihan Li,1,2,* Jinhui Li,2,* Xiaofeng Hu,2,* Yanfeng Lin,1,2 Lang Yang,1,2 Shaofu Qiu,2 Hui Ma,*,3 Peng Li,2 Hongbin Song2 1College of Military Medicine, Academy of Military Sciences, Beijing, People's Republic of China; 2Center for Disease Control and Prevention of PLA, Beijing, People's Republic of China; 3The Sixth Medical Center of PLA General Hospital, Beijing, People's Republic of China*These authors contributed equally to this workCorrespondence: Peng Li; Hongbin Song Tel/ Fax +86-10-66948475Email jiekenlee@126.com; hongbinsong@263.netBackground: The New Delhi metallo-β-lactamase-1 (NDM-1)-positive plasmid and its variants pose daunting threats to public health. Hospital sewage was considered as an important reservoir of antibiotic genes. Numerous and diverse taxa of multidrug-resistant (MDR) bacteria carrying NDM-1-positive plasmids have been identified during routine surveillance of hospital sewage. We herein report a carbapenem-resistant Acinetobacter towneri strain AeBJ009 with an NDM-1-positive plasmid isolated from hospital sewage.Materials and Methods: Bacteria were isolated from cultures of hospital sewage and identified by using the Vitek 2 compact system and 16S rRNA sequencing. The blaNDM-1 gene was amplified and confirmed by sequencing. Antimicrobial susceptibility testing was performed using AST-GN14 on the Vitek2 compact system. In addition, the blaNDM-1 gene was located by Southern blotting. Conjugation experiment and whole-genome sequencing were performed for further analysis.Results: Strain AeBJ009 was isolated from hospital sewage and identified as A. towneri. Antimicrobial susceptibility testing revealed an MDR phenotype. Pulsed-field gel electrophoresis and Southern blotting showed that strain AeBJ009 carries three plasmids and that blaNDM-1 is located on the 47kb plasmid pNDM-AeBJ009. However, the conjugation experiment to transfer pNDM-AeBJ009 to Escherichia coli strain J53 was unsuccessful. Whole-genome sequencing found that pNDM-AeBJ009 contains a Tn 125 element carrying blaNDM-1. The ble gene downstream of blaNDM-1 displayed a single-nucleotide polymorphism compared to its homologue on plasmid pM131_NDM1. BLAST analysis using the Comprehensive Antibiotic Resistance Database identified no gene polymorphisms with 100% identity to our ble variant.Conclusion: The A. towneri strain AeBJ009 exhibiting an extended spectrum of antibiotic resistance was isolated from hospital sewage and may potentially exacerbate the risk of MDR bacterial infections. The prevention of nosocomial infections due to drug-resistant bacteria will require enhanced monitoring and control of MDR pathogens in environmental reservoirs.Keywords: NDM-1, ble, Acinetobacter towneri, drug resistance

Tingyan Zhang,1,2,* Yanfeng Lin,2,3,* Peihan Li,2,3,* Zhonghong Li,2 Xiong Liu,2 Jinhui Li,2 Lizhong Li,2 Kaiying Wang,2,3 Zhongdong Liu,1 Peng Li,2 Lanfen Lu,4 Hongyan Wang1 1School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, People's Republic of China; 2Chinese PLA Center for Disease Control and Prevention, Beijing, People's Republic of China; 3Academy of Military Medical Sciences, Beijing, People's Republic of China; 4Department of Laboratory Diagnosis, Sun Yat-Sen University Affiliated Zhongshan Hospital, Zhongshan, Guangdong, People's Republic of China*These authors contributed equally to this workCorrespondence: Peng Li; Hongyan Wang Email jiekenlee@126.com; 18623717897@163.comBackground: The emergence of multidrug-resistant Citrobacter freundii poses daunting challenges to the treatment of clinical infections. The purpose of this study was to characterize the genome of a C. freundii strain with an IncX3 plasmid encoding both the blaNDM-1 and blaSHV-12 genes.Methods: Strain ZT01-0079 was isolated from a clinical urine sample. The Vitek2 system was used for identification and antimicrobial susceptibility testing. The presence of blaNDM-1 was detected by PCR and sequencing. Conjugation experiments and Southern blotting were performed to determine the transferability of the blaNDM-1- carrying plasmid. Nanopore and Illumina sequencing were performed to better understand the genomic characteristics of the strain.Results: Strain ZT01-0079 was identified as C. freundii, and the coexistence of blaNDM-1 and multiple drug resistance genes was confirmed. Electrophoresis and Southern blotting showed that blaNDM-1 was located on a ∼ 53kb IncX3 plasmid. The NDM-1-encoding plasmid was successfully transferred at a frequency of 1.68× 10− 3. Both the blaNDM-1 and blaSHV-12 genes were located on the self-transferable IncX3 plasmid.Conclusion: The rapid spread of the IncX3 plasmid highlights the importance of continuous monitoring of the prevalence of NDM-1-encoding Enterobacteriaceae. Mutations of existing carbapenem resistance genes will bring formidable challenges to clinical treatment.Keywords: C. freundii, whole-genome sequencing, genomics analysis

Peihan Li, 1, 2,* Yanfeng Lin, 1, 2,* Xiaofeng Hu, 2,* Yuqi Liu, 1, 2 Mei Xue, 3 Lang Yang, 1, 2 Jinhui Li, 2 Lei Zha, 2 Kaiying Wang, 1 Kezong Qi, 3 Shaofu Qiu, 2 Peng Li, 2 Hongbin Song 2 1Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, People's Republic of China; 2Center for Disease Control and Prevention of PLA, Beijing, People's Republic of China; 3Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, Anhui Agricultural University, Anhui, People's Republic of China*These authors contributed equally to this workCorrespondence: Peng Li; Hongbin SongCenter for Disease Control and Prevention of PLA, 20 DongDa Street, Fengtai District, Beijing 100071, People's Republic of ChinaTel/Fax +86-10-66948475Email jiekenlee@126.com; hongbinsong@263.netPurpose: Carbapenem-resistant Enterobacter cloacae complex has been reported worldwide and becomes a new challenge for clinical management. The present study was to characterize the IncX3 plasmid encoding blaNDM-1 and blaSHV-12 gene in E. hormaechei sequence.Materials and Methods: EcHK001 was recovered from the sputum sample of a patient. Species identification and antimicrobial susceptibility testing were performed using the VITEK 2 system, while further classification was carried out by hsp60 typing. The presence of NDM-1 was detected by PCR and sequencing. Conjugation experiments and southern blotting were carried out to determine the transferability of the NDM-1-carrying plasmid. Whole-genome sequencing and analysis were conducted to better understand the molecular characteristics of the multi-drug resistant isolate.Results: Strain EcHK001 was classified as E. hormaechei of new sequence type 1000. Multiple drug-resistant genes were detected. The blaNDM-1 and blaSHV-12 genes were located on a self-transferable IncX3 plasmid. Synonymous mutations were identified in the genes encoding TEM-1 and ACT-17. Phylogenetic analysis indicated that EcHK001 clustered into a different clade from domestic strains.Conclusion: The rapid spread of the recurrent IncX3 plasmid highlights the need for continuous surveillance of the NDM-1 dissemination. The presence of mutations in existing carbapenem-resistant genes may generate potential new variants and raise serious challenges for clinical treatment.Keywords: multidrug-resistant, NDM-1, SHV-12, enterobacter hormaechei