Detection of Metallo Beta Lactamases Production in Pseudomonas Aeruginosa by Phenotypic Methods from Clinical Isolates in a Tertiary Care Hospital

Dr. Rajitha K, Dr. Mariraj Jeer, Dr. Pushpalatha H, Vanitha Shree T V

Abstract: Introduction: Pseudomonas aeruginosa causes infections majorly of skin, bone, heart, eye, and septicemia. It is a primary contributor to persistent pulmonary infections in children and young people with cystic fibrosis. In the 1980s, carbapenems were created and are utilized as a last option for treating severe infections caused by multidrug - resistant Gram - negative bacilli. Resistance to carbapenems was observed in 1990s. The primary factor contributing to resistance is the synthesis of metallo beta - lactamases (MBL), which hydrolyze all the beta - lactams, including carbapenems. This study aimed to identify Pseudomonas aeruginosa from clinical specimen and its antibiotic susceptibility pattern, also to detect metallo - beta - lactamase production by phenotypic methods, which would assist clinicians to treat patients and improves the curable rate of patients. Materials & Methods: It is a prospective study done on various clinical samples received to central laboratory in department of microbiology, BMCRC Ballari. A total of 100 clinical samples of Pseudomonas aeruginosa were isolated and identified based on gram staining, colony morphology, preliminary tests and biochemical reaction as per standard microbiological procedures followed by Antibiotic susceptibility testing was carried out by using the Kirby - Bauer disc diffusion method on Mueller - Hinton agar and interpreted according to the Clinical Laboratory Standards Institute guidelines (CLSI) of 2023. Later Detection of Metallo - Beta - Lactamases was performed by using the Combined Disk Test, Double Disk Synergy Test, and MBL - E Test. Results: This study examined a total of 100 isolated Pseudomonas aeruginosa were identified from clinical specimen for the development of metallo beta - lactamases. From the 100 samples analyzed, 14 (14%) exhibited resistance to Imipenem, with 11 (11%) identified as MBL producers and the remaining as non - MBL producers. MBL production in CDST and E - test was 9 (81.8%) and 8 (72.7%), respectively and it was 7 (63.6%) in case of DDST. Conclusion: The current study found a relatively high prevalence of Pseudomonas MBL producers with resistance to imipenem. A significant degree of resistance is observed with frequently utilized antibiotics, necessitating the usage of polymyxin in most instances due to the heightened susceptibility of Pseudomonas to polymyxin. Furthermore, our research endorses the utilization of E - tests, CDST, and DDST for the identification of Pseudomonas MBL producers in areas where PCR detection is impossible.

Keywords: Metallo - beta lactamases, CDT, DDST, Multidrug Resistant, Pseudomonas aeruginosa