• Smitha Bagali Associate Professor, Department of Microbiology, BLDE (DU) Shri B. M. Patil Medical College, Hospital & Research Centre, Vijayapura, Karnatak, India.
  • Laxmi Kakhandaki Associate Professor, Department of Microbiology, BLDE (DU)Shri B. M. Patil Medical College, Hospital & Research Centre, Vijayapura, Karnataka, India.
  • Rashmi Karigoudar Assistant Professor, Department of Microbiology, BLDE (DU) Shri B. M. Patil Medical College, Hospital & Research Centre, Vijayapura, Karnataka, India.
  • Shivali V Gajul Lecturer, Department of Microbiology, BLDE (DU) Shri B. M. PatilMedical College, Hospital & Research Centre, Vijayapura, Karnataka, India.
  • Prakash G Mantur Associate Professor, Department of Medicine, BLDE (DU) ShriB. M. Patil Medical College, Hospital & Research Centre, Vijayapura, Karnataka, India.
  • Praveen R Shahapur Professor, Department of Microbiology, BLDE (DU) Shri B.M. Patil Medical College, Hospital & Research Centre, Vijayapura, Karnataka, India.



Imipenem resistance, Phenotypic methods, Colistin sensitivity.



The spread of carbapenem resistant bacteria has caused grave concern due to the limited choice in antibiotics for treating infections caused by them. The emergence of  metallo beta-lactamse (MBL) producing  gram negative bacilli poses a therapeutic challenge and is of serious concern for infection control in hospital environment.

Materials & Methods:

A total of 475 non repeat clinical isolates of family Enterobacteriaceae were included in the study. Resistance to imipenem was determined in isolates by disc diffusion & minimum inhibitory concentration (MIC) method. Imipenem resistant  isolates  were tested for MBL production by combined disc diffusion test and modified Hodge test.


Out of the 475 Enterobacteriaceae strains,  20 showed resistance to imipenem. MBL activity was detected in all 20 (4.2%) isolates by combined disc diffusion test, in 18 isolates by modified Hodge test. The MBL producing isolates included clinical strains of Klebsiella spp (45%), E. coli (40%), Citrobacter spp (15%).  Majority of the MBL isolates were from Intensive care unit (65%), from patients with comorbid conditions and with invasive devices.  MBL producing isolates showed high level of resistance to aminoglycosides and fluoroquinolones but all were susceptible to colistin.


The need of the hour is to detect MBL producing isolates for better patient outcomes, to execute prompt infection control measures and decrease the escalation of resistance.


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