Showing papers on "New Delhi metallo-beta-lactamase 1 published in 2014"

Carbapenemase-producing Enterobacteriaceae: overview of a major public health challenge.

Abstract: Bacterial resistance to antibiotics has become a major source of concern for public health. Enterobacteriaceae are among the most common human pathogens, causing community-acquired as well as hospital-acquired infections. Carbapenem-resistant Enterobacteriaceae have been increasingly reported worldwide since their first identification more than 20 years ago. Three main classes of carbapenemases have been identified: Ambler class A beta-lactamase (KPC), class B (metallo-enzymes), and class D (OXA-48 type). Klebsiella pneumoniae carbapenemases (KPC) was first reported in the United States in the late 1990s and since then worldwide, with a marked endemicity in the United States, Greece, and now Italy. Carbapenemase NDM-1 (New Delhi metallo-beta-lactamase-1) is one of the most recently reported metallo-enzymes. It has spread widely in the Indian sub-continent and now worldwide. Carbapenemases of the oxacillinase-48 type (OXA-48) have been identified mostly in Mediterranean and southern European countries with a rapid spread. An early and quick identification of carbapenemase-producing infected patients, but also of carriers, is mandatory to prevent the spread of these highly resistant pathogens. The early identification of carriers and implementing of cohorting strategies is the only means to prevent nosocomial outbreaks caused by carbapenemase, with very few, if any, therapeutic options.

Pathogenicity of pan-drug-resistant Serratia marcescens harbouring blaNDM-1

Abstract: Objectives To characterize a pan-drug-resistant Serratia marcescens clinical isolate carrying the New Delhi metallo-β-lactamase (NDM)-1. Methods The presence of β-lactamase genes was examined by PCR and sequencing. Antibiotic susceptibility was determined by antibiotic gradient test. Transformation assays, transconjugation assays, PFGE and PCR-based replicon typing were used for plasmid analysis. Horizontal gene transfer was evaluated by liquid mating using Escherichia coli J53 as a recipient. Pathogenicity of NDM-1 expressing S. marcescens was analysed using the Galleria mellonella infection model. Results S. marcescens isolate SM1890 was non-susceptible to all tested antibiotics, with minocycline retaining intermediate activity. blaNDM-1 was located on a 140 kb IncA/C-type plasmid which was transferable to E. coli and Klebsiella pneumoniae by conjugation. The LD50 of the NDM-positive, SM1890 isolate was higher than that of other, NDM-1 negative, S. marcescens strains. Conclusions The presence of a blaNDM-1-harbouring IncA/C plasmid resulted in marked resistance to β-lactam antibiotics, but had no significant effect on virulence of isogenic strains. Because of the intrinsic resistance of S. marcescens to colistin and reduced susceptibility to tigecycline, treatment options for infections by NDM-1-positive isolates are extremely limited in this species.

Detection of New Delhi metallo beta lactamase-1 (NDM-1) carbapenemase in Pseudomonas aeruginosa in a single centre in southern India.

Abstract: Background & objectives: New Delhi metallo β-lactamase-1 (NDM-1) producing Pseudomonas aeruginosa isolates are potential threat to human health. This study was conducted to detect the presence of blaNDM-1 in carbapenem resistant P. aeruginosa in a tertiary care center in southern India. Methods: Sixty one carbapenem resistant clinical isolates of a total of 212 P. aeruginosa isolates cultured during the study period were screened for the presence of NDM-1by PCR. Clinical characteristics of the NDM-1 positive isolates were studied and outcome of the patients was followed up. Results: Of the 61 isolates, NDM-1 was detected in four isolates only. These were isolated from patients in the intensive care units and chest medicine ward. The source specimens were pus, sputum, bronchoalveolar lavage and endotracheal aspirate. The NDM-1 producers were susceptible only to polymyxin B. Only one patient responded to polymyxin B therapy, while the others succumbed to the infection. Conclusion: These findings reveal that NDM-1 is not a major mechanism mediating carbapenem resistance in P. aeruginosa in this centre. However, continuous surveillance and screening are necessary to prevent their dissemination.

NDM-1 (New Delhi metallo beta lactamase-1) producing Gram-negative bacilli: Emergence & clinical implications

Abstract: Backgound & objectives: Resistance to carbapenems in Gram-negative bacteria conferred by NDM-1 is a global health problem. We investigated the occurrence of NDM-1 in clinical isolates of Gram-negative bacilli in a tertiary care hospital in Kashmir valley, India. Methods: Gram-negative bacilli from different clinical isolates were included in the study. Antimicrobial susceptibility was performed by Kirby Bauer disk diffusion method and interpreted using Clinical Laboratory Standards Institute (CLSI) guidelines. Isolates resistant to carbapenems were subjected to different phenotypic test such as modified Hodge test (MHT), boronic acid and oxacillin based MHT ( BA-MHT and OXA-MHT), combined disk test and minimum inhibitory concentration (MIC) with imipenem and imipenem -EDTA for determination of class B metallo enzymes. Presence of bla NDM-1 gene was established by PCR and confirmed by sequencing. Results: Of the total 1625 Gram-negative isolates received, 100 were resistant to imipenem. Of the 100 isolates, 55 (55%) were positive by modified Hodge test indicating carbapenemase production. Of the 100 isolates tested by MHT, BA-MHT and OXA-MHT, 29 (29%) isolates belonged to Class A and 15 (15%) to Class B, while 56 (56%) isolates were negative. Of the 15 class B metallo beta lactamase producers, nine carried the bla NDM- 1 gene. NDM-1 was found among Escherichia coli (2 isolates) , Klebsiella pneumoniae (2 isolates) , Citrobacter freundii (3 isolates) , Acinetobacter spp (1 isolate) , and one isolate of Pseudomonas aeruginosa. Isolates were resistant to all antibiotic tested except polymyxin B and tigecycline. Interpretation & conclusions: Our study showed the presence of clinical isolates expressing NDM-1 in Srinagar, Jammu & Kashmir, India. These isolates harbour plasmid mediated multiple drug resistant determinants and can disseminate easily across several unrelated genera. To halt their spread, early identification of these isolates is mandatory.