Detection of Metallo β-Lactamase in Acinetobacter Species Using Phenotypic Methods with their Antibiotic Resistance Profile in Tertiary Care Hospital

Background: Acinetobacter species are commonly found in nature, in water, and in soil, and also, and they have been isolated from humans and animals. In the hospital setting, Acinetobacter species has emerged as a major opportunistic pathogen, being able to colonize and develop infections in patients. In Acinetobacter species, β-lactamases and outer membrane alterations are likely to function together to impart resistance. Understanding the epidemiology, and resistance mechanism, and for infection management and preventing a potential global health crisis, techniques for identifying Carbapenem-Resistant-Acinetobacter species are essential.

Aim: To detect Metallo β-Lactamase (MBL) in Acinetobacter species with their antimicrobial susceptibility pattern.

Material and Methods: 100 Acinetobacter species isolates from various clinical samples such as blood, cerebrospinal fluid, sputum, bronchoalveolar lavage, pus, urine, wound swab, and body fluids were included in the study. Phenotypic tests such as, Disc Potentiation test & Modified Hodge test were used to detect the presence of Metallo β-lactamase in imipenem & meropenem-resistant isolates.

Results: The highest prevalence of Acinetobacter was found in blood (37%), followed by sputum (31%) and others [pus, urine, ascitic fluid, cerebrospinal fluid (CSF), bronchoalveolar Lavage (BAL), and pleural fluid]. A maximum number of Acinetobacter were isolated from MICU followed by medicine and surgery. The Modified Hodge test yielded the largest percentage of MBL-positive Acinetobacter isolates (67.26%) when compared to the Disc Potentiation test method (50.45%). Conclusion: Early detection of Metallo β-lactamase production is essential for planning appropriate treatment according to the resistance mechanisms of the multi-drug resistant strains, as well as for efficient infection control procedures to prevent the spread of infection.