Detection of metallo beta lactamase production in imipenem resistant gram negative bacilli non fermenters isolated in a Tertiary Care Hospital.

Abstract

Objectives: Metallo-beta lactamase (MBL) producing non fermenter Gram negative bacilli is an emerging warning and cause of worry as they have established as one of the most feared resistance mechanisms and are the foremost cause of nosocomial infections worldwide. Carbapenem, including Imipenem, Meropenem and Doripenem are often used as a last remedy for treatment of infections caused by Pseudomonas aeruginosa, Acinetobacter and other Gram-negative. The present study was designed to explore the distribution of imipenem resistant non-fermenter Gram-negative bacilli isolates in different age groups. Study Design: Cross sectional Descriptive study. Setting: Microbiology laboratory, PGMI, Lahore. Period: January 2015 to December 2015. Material & Methods: 53 imipenem resistant NFGNB that were isolated from appropriate sampling of patients suffering from several infections were analyzed by using different standard microbiological techniques like microscopy, culture methods, biochemical reactions and antibiotic susceptibility using Kirby-Bauer method. MBL recognition was performed by imipenem-2MPA double disc synergy test (DDST). Results: This study shows the frequency of imipenem resistant non-fermenter Gram-negative bacilli isolated from various clinical wards. Maximum NFGNB were recovered from surgery/surgical allied 35.84% followed by ICU 28.3%, medicine /medicine allied 20.75%, pediatrics 9.4% and gynae/obs 5.6% respectively. MBL production was identified among different imipenem resistant non-fermenter Gram-negative bacilli isolates by DDST using 2-MPA. Out of total 53 imipenem resistant non-fermenter Gram Negative Bacilli 37 Pseudomonas aeruginosa 20(54.05%) were MBL positive. Out of 13 Acinetobacter baumannii and 2 Pseudomonas luteola, 11(84.61%) Acinetobacter baumannii and 1(50%) Pseudomonas luteola were positive for MBL production. None of the Acinetobacter junii indicated MBL production. Conclusion: Double disc synergy test is operational for detection of MBL producers among NFGNB. It can be established in our routine clinical microbiology laboratories, for the MBL recognition especially in imipenem resistant isolates as of its cost efficiency.