title: Isolation and molecular characterization of New Delhi metallo-beta-lactamase-1 producing superbug in Bangladesh.
abstract: BACKGROUND
  New Delhi metallo-beta-lactamse-1 (NDM-1) producing superbugs create a global public health problem because of their resistance to most antibiotics. This study was conducted to determine the presence of MBL producers, including NDM-1 producers, in Bangladesh, along with the antimicrobial resistance patterns of these organisms.
  
  
  METHODS
  Thirty-five isolates resistant to imipenem by disk diffusion technique were investigated for MBL production. Minimum inhibitory concentration (MIC) of imipenem was determined by agar dilution method. MBL producers were phenotypically detected by double disk synergy test and combined disk assay. Gene encoding blaIMP-1, blaIMP-2, blaVIM-1, blaVIM-2, blaNDM-1 and class 1 integron was identified by PCR.
  
  
  RESULTS
  Thirty-one (88.57%) MBL producers were detected by PCR, 24 (68.57%) by double disk synergy test, and 30 (85.71%) by combined disk assay. Eight (22.86%) were positive for blaNDM-1, 13 (37.15%) for blaVIM-1, 21 (60.00%) for blaVIM-2, 18 (51.43%) for blaIMP-1, and 9 (25.71%) for blaIMP-2. More than one blaMBL was present in 23 (65.71%) of the isolates. MIC of imipenem of MBL producers ranged from ≥256 µg/ml to ≤8 µg/ml. All the NDM-1 producing isolates carried class 1 integron. NDM-1 producers were 100% resistant to amoxicillin, cephradine, cefuroxime, ceftazidime, cefotaxime, ceftriaxone, aztreonam, gentamicin and piperacillin, 87.5% to amikacin, 75% to ciprofloxacin, and 62.5% to co-trimoxazole and the combination of tazobactam and piperacillin. All were sensitive to colistin.
  
  
  CONCLUSIONS
  The results of this study provide insight into the presence of blaMBL, including blaNDM-1, in Bangladesh. Urgent epidemiological monitoring of MBL producers in Bangladesh may combat their rapid dissemination.
authors.affiliation: Dhaka Medical College, Department of Microbiology, Dhaka, Bangladesh. refath_farzana@yahoo.com
authors.forename: Refath
authors.initials: R
authors.lastname: Farzana
authors.forename: Sm
authors.initials: S
authors.lastname: Shamsuzzaman
authors.forename: Kazi Zulfiquer
authors.initials: KZ
authors.lastname: Mamun
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001459:Bangladesh / Q000453:epidemiology; D003430:Cross-Sectional Studies; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; C552864:beta-lactamase NDM-1