Biofilm and MBL production among imipenem resistant Pseudomonas aeruginosa and Acinetobacter species

  • Yang Metok Manipal College of Medical Sciences, Pokhara, Nepal; Kantipur College of Medical Sciences, Kathmandu, Nepal
  • Supram Hosuru Subramanya Manipal College of Medical Sciences, Pokhara, Nepal
  • Upendra Thapa Shrestha Kantipur College of Medical Sciences, Kathmandu, Nepal
  • Leandro Reus Rodrigues Perez Hospital Mae de Deus, Porto Alegre, Brazil
  • Nabaraj Adhikari Kantipur College of Medical Sciences, Kathmandu, Nepal
  • Niranjan Nayak Manipal College of Medical Sciences, Pokhara, Nepal
Keywords: Pseudomonas aeruginosa, Acinetobacter spp., Imipenem-resistance, MBL, Biofilm


Pseudomonas aeruginosa and Acinetobacter species are the primary cause of nosocomial infections. The advent of Metallo-beta-lactamase (MBL) and biofilm-producing bacterial strains poses a serious threat to reserve drugs such as carbapenem. The objective of this study was to determine the rate of MBL and biofilm production among imipenem resistant P. aeruginosa (IRPA) and imipenem resistant Acinetobacter spp. (IRAS) isolates. A total of 79 P. aeruginosa and 117 Acinetobacter spp. were isolated from various clinical specimens of patients from July 2016 to January 2017 at Manipal Teaching Hospital, Pokhara. MBL in IRPA and IRAS isolates were detected by Combined disc test and E-test. Biofilm production in imipenem resistant isolates was carried out by Microtitre plate assay. Fifteen (19%) P. aeruginosa and 57 (48.7%) Acinetobacter spp. were imipenem resistant isolates. MBL producers were found among 53.3% of IRPA and 38.6% of IRAS, whereas 100% of IRPA and 82.5% of IRAS were biofilm producers. All the biofilm producer IRPA isolates were Extensively Drug-Resistant (XDR), and a larger proportion of XDR IRAS strains were of high biofilm-producing phenotype. However, the majority of imipenem resistant (80% of IRPA and 49.1% of IRAS) and MBL producing (63%) isolates were weak biofilm formers. The study demonstrated the high capability of IRPA and IRAS to form a biofilm, which was strongly related to higher drug resistance. Nonetheless, imipenem resistant and MBL producer isolates showed an analogous association with the degree of biofilm formation. These MBL cum biofilm producer isolates were better susceptible to polymyxin B and ampicillin-sulbactam.


Author Biography

Leandro Reus Rodrigues Perez, Hospital Mae de Deus, Porto Alegre, Brazil




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How to Cite
Metok, Y., Subramanya, S., Shrestha, U., Perez, L., Adhikari, N., & Nayak, N. (2020). Biofilm and MBL production among imipenem resistant Pseudomonas aeruginosa and Acinetobacter species. MicroMedicine, 8(2), 63-73. Retrieved from
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