Metallo β-lactamases: A perspective and implications

The emergence of Carbapenem-resistant organisms from the family Enterobacteriaceae is a major challenge in the intensive care facilities. They produce carbapenemases which inhibit carbapenems belonging to the Ambler classification group B and they depend on heavy metals like Zn ++for hydrolysis of β-lactam ring. Most of the clinically important metallo-β-lactamases (MBL) belong to five different families (IMP, VIM, SPM, GIM, and SIM). They are typically transmitted by mobile genetic elements inserted into integrons and spread through Pseudomonas spp, Acinetobacter spp. In a study from New Delhi, 36 out of 56 P. aeruginosa species were MBL positive and from Vellore MBL was detected in 20 out of 61 P. aeruginosa 20 (32%). Inappropriate antibiotic usage, defensive practices by medical practitioners, promotion of antibiotics by pharmaceutical companies are major hurdles in the direction of rational use of antibiotics. Intensified infection control strategy should be adopted to prevent emergence and spread of carbapenemase-producing organisms