Project description:The prevalence of Klebsiella pneumoniae coproducing carbapenemase metallo-?-lactamase 1 (NDM-1) and OXA-48 has been increasing globally since 2013. The complete genome of KP617 was sequenced and assembled into a circular chromosome and two plasmids. This sequence provides the genetic background for understanding the evolution of carbapenemase genes in K. pneumoniae KP617.
Project description:After an increase in carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections and associated deaths in the neonatal unit of a South Africa hospital, we conducted an outbreak investigation during October 2019-February 2020 and cross-sectional follow-up during March 2020-May 2021. We used genomic and epidemiologic data to reconstruct transmission networks of outbreak-related clones. We documented 31 cases of culture-confirmed CRKP infection and 14 deaths. Two outbreak-related clones (blaNDM-1 sequence type [ST] 152 [n = 16] and blaOXA-181 ST307 [n = 6]) cocirculated. The major clone blaNDM-1 ST152 accounted for 9/14 (64%) deaths. Transmission network analysis identified possible index cases of blaOXA-181 ST307 in October 2019 and blaNDM-1 ST152 in November 2019. During the follow-up period, 11 new cases of CRKP infection were diagnosed; we did not perform genomic analysis. Sustained infection prevention and control measures, adequate staffing, adhering to bed occupancy limits, and antimicrobial stewardship are key interventions to control such outbreaks.
Project description:BackgroundCarbapenemase producing Enterobacteriaceae are becoming a major public health concern globally, however, relatively little is known about the molecular and clinical epidemiology of these organisms in many parts of the world.MethodsAs part of a laboratory surveillance programme, 96 carbapenem non-susceptible Enterobacteriaceae isolates from clinical samples from patients in seven hospitals were referred for investigation for carbapenemases. Using polymerase chain reaction (PCR) to screen for a collection of genes encoding carbapenemases, 33 of 96 (34.5%) isolates were confirmed as carbapenemase producers. NDM-1 producers were the most prevalent at 64% (21/33) whilst OXA-181 was the second most common carbapenemase constituting 24.5% (8/33) of the carbapenemase producing isolates. Seven of these eight OXA-181 positive isolates underwent further characterisation with screening for other transmissible antimicrobial resistance determinants using PCR. Clonal relatedness was explored using Multilocus sequence typing (MLST) and Pulsed Field Gel Electrophoresis (PFGE). Plasmid characterisation was performed including restriction analysis and transfer by conjugation or transformation.ResultsIn addition to the OXA-181 gene, all contained other transmissible resistance determinants including extended spectrum β-lactamases, oxacillinases or 16S rRNA methylase genes, but none contained metallo-β-lactamases or serine carbapenemases. All isolates had a multidrug resistant phenotype with two isolates being resistant to every antibiotic tested including colistin. Multilocus sequence typing confirmed five isolates belonged to ST17 and two to ST14, with those belonging to the same sequence type having identical PFGE profiles. The OXA-181 gene was typically carried on large plasmids which were mostly non-conjugative.ConclusionsOXA-181 carbapenemase appears to be an important and probably under-recognised cause of carbapenem resistance in Enterobacteriaceae in Singapore. Further coordinated research into clinical and molecular epidemiology of carbapenemases is urgently required in Singapore and throughout Asia.
Project description:BackgroundShewanella genus, as an important carrier of resistance genes, has the potential to transmit resistance to many antimicrobials in many circumstances, especially in aquatic environment. The aim of the study was to describe the risk of Shewanella xiamenensis in hospital environment through analysis of genomic comparison and resistance status.MethodsSeven S. xiamenensis strains were isolated from hospital wastewater. PCR and Sanger sequencing were carried out for detection of common carbapenemase genes. Antimicrobial susceptibility testing was performed to determine the antimicrobial profile. Whole genome sequencing was applied, and sequences were further used for genomic analysis.ResultsSeven Shewanella xiamenensis were all positive for bla NDM and bla OXA-48. Antimicrobial susceptibility testing showed all Shewanella xiamenensis were resistant to cefotaxime, ceftazidime, imipenem, meropenem, gentamycin and trimethoprim-sulfamethoxazole. Whole genome sequencing and phylogenetic analysis demonstrated the diversity of Shewanella xiamenensis despite isolating from one wastewater pool.ConclusionTo the best of our knowledge, this is the first report of detection of three types bla OXA-48-like genes in one hospital in China. And we have detected multi-drug resistant S. xiamenensis from hospital wastewater. This emphasizes that the presence of naturally existing carbapenemases in the environment may be significantly overlooked and that the bla OXA-48-like genes in China may originate through the horizontal gene transfer from S. xiamenensis to Enterobacterales rather than import from other countries.
Project description:We present here the first report of an OXA-181-producing Klebsiella pneumoniae isolated from the fecal specimen of a patient in China. The OXA-181-encoding gene bla OXA-181 was located on a 51 kb IncX3-type plasmid. Conjugation assay and whole-genome sequencing analysis revealed that this transferrable plasmid in the K. pneumoniae isolate might have originated from Escherichia coli and have the potential to mediate the spread of bla OXA-181.
Project description:BACKGROUND:Carbapenems are used for the treatment of serious infections caused by multidrug-resistant Klebsiella pneumoniae. Resistance to carbapenems in K. pneumoniae is mainly due to metallo-beta-lactamases (NDM, IMP, and VIM) and class D oxacillinase (OXA-48-like). AIM AND OBJECTIVE:This study was undertaken to detect the genes encoding for carbapenemase in K. pneumoniae and to determine the clonal relatedness of selected isolates of K. pneumoniae producing NDM and OXA-48 by pulsed-field gel electrophoresis method (PFGE). MATERIALS AND METHODS:The isolates were collected over a period of 1 year. A total of 370 clinically significant, nonduplicate isolates of K. pneumoniae were included in this study. Phenotypic tests for the detection of carbapenemases were performed for all the isolates. Polymerase chain reaction (PCR) was carried out for the detection of carbapenemase genes such as bla KPC, bla IMP, bla VIM, bla NDM, and bla OXA-48. PFGE was performed, and the PFGE profiles were analyzed and compared using BioNumerics version 7.6. RESULTS:Of the 370 isolates of K. pneumoniae, carbapenemase genes were detected in 13.78% (51/370). bla OXA-48 was the prevalent gene detected followed by bla NDM and bla KPC. Thirty strains of K. pneumoniae selected by PFGE analysis were divided into five clusters (A, B, C, D, and E). Cluster C was the major type detected carrying bla NDM and bla OXA-48 genes. CONCLUSION:bla OXA-48 was the most prevalent gene detected in this study. PCR is useful in detecting carbapenemase genes, especially bla NDM, which may show false susceptibility to carbapenems. There was no direct correlation detected between PFGE profiles and antibiotic susceptibility pattern. PFGE has revealed the genomic diversity among isolates, thereby suggesting heterogeneity in strain circulation within intensive care unit and wards of the hospital. Monitoring and molecular typing is essential to curtail the spread of multidrug-resistant strains and control the outbreaks of infection.
Project description:The whole-genome sequence of a carbapenem-resistant Klebsiella pneumoniae strain, PittNDM01, which coproduces NDM-1 and OXA-232 carbapenemases, was determined in this study. The use of single-molecule, real-time (SMRT) sequencing provided a closed genome in a single sequencing run. K. pneumoniae PittNDM01 has a single chromosome of 5,348,284 bp and four plasmids: pPKPN1 (283,371 bp), pPKPN2 (103,694 bp), pPKPN3 (70,814 bp), and pPKPN4 (6,141 bp). The contents of the chromosome were similar to that of the K. pneumoniae reference genome strain MGH 78578, with the exception of a large inversion spanning 23.3% of the chromosome. In contrast, three of the four plasmids are unique. The plasmid pPKPN1, an IncHI1B-like plasmid, carries the blaNDM-1, armA, and qnrB1 genes, along with tellurium and mercury resistance operons. blaNDM-1 is carried on a unique structure in which Tn125 is further bracketed by IS26 downstream of a class 1 integron. The IncFIA-like plasmid pPKPN3 also carries an array of resistance elements, including blaCTX-M-15 and a mercury resistance operon. The ColE-type plasmid pPKPN4 carrying blaOXA-232 is identical to a plasmid previously reported from France. SMRT sequencing was useful in resolving the complex bacterial genomic structures in the de novo assemblies.
Project description:We detected for the first time blaNDM-5 and blaOXA-181 in Escherichia coli isolates from hospitalized patients and healthy volunteers in Chad. These resistance genes were located on IncX3 and IncF plasmids. Despite the large diversity of E. coli clones, the identified resistant intestinal isolates belonged mainly to the same sequence type.