Molecular characterization of metallo-beta lactamase geneblaimp-1 in imipenem resistant Pseudomonas aeruginosa isolates from patients of chronic suppurative otitis media at a tertiary care hospital

Abstract

Chronic suppurative otitis media (CSOM) is a chronic inflammation of the middle ear and mastoid cavity, persisting for more than 2 weeks. is one of the most common organisms to cause CSOM. Carbapenems are among the most effective antibiotics used against infections resistant to carbapenems is often associated with production of metallo-ß-lactamases strains. Detection of MBLs producing strains can be effective for optimal treatment of patients for the control and spread of resistance. The main purpose of the study is to determine the imipenem resistant carrying metallo-ß-lactamase (MBL) genebla in Patients of Chronic Suppurative Otitis Media at a Tertiary care hospital”This was a cross sectional study carried out in the Department of Microbiology and ENT Department for a period of 1 year between July 2021 to July 2022. A total of 185 patients clinically suspected cases for CSOM were studied. Swabs taken from discharging ears were sent for Gram’s staining, culture and antibiotic sensitivity test as per the latest CLSI guidelines. The isolates were further tested for MBL by screening test, by Imipenem – EDTA combined disc test, and MBL E test (Imipenem). The DNA was extracted by using Qiagen DNA Extraction kit and  gene for isolates was detected by conventional PCR.In our study the number of cases clinically diagnosed of having CSOM was 185, out of which 63 (34%) was found to be culture positive for CSOM infection. Males were 38 (60.3%) as compared to that of female 25 (39.6%), Both the ears affected were almost in equal distribution, with the left ear being 32 (50.7%) and the right ear being 28 (44.4%) while in 3 cases (4.7%) it was bilateral. Gram negative bacilli were (74.6%), being the most common isolate with 47.6% followed by 19% and among the Gram positive isolates (25.3%). (12.6%) was the most common isolate. Colistin (96.6%), Piperacillin‑tazobactam (73.3%), Amikacin (76.6.3%), and Cefepime (73.3%) were found to be the most effective Antibiotics. The resistance to ciprofloxacin was (56.6%), Levofloxacin (50%), Piperacillin (46.6%), Gentamicin(36.6%), Imipenem (36.6%), Tobramycin (30%), Ceftazidime (30%). Out of 30 isolated 11(36.6%) were screening test-positives for MBL by Imipenem – EDTA combined disc test, and MBL E test (Imipenem). The bla  gene was detected in all 11 (36.6%) of the isolates of In the present study being the most common isolate with Colistin, Piperacillin‑tazobactam, Amikacin, and cefepime to be the most effective antibiotics. Resistance of isolates to Imipenem due to MBL enzymes is increasing in the Kanpur region (36.6%). Judicial use of broad spectrum antibiotics, like Imipenem is the need of the hour, hence knowledge of the etiological agents of CSOM and their antibiogram is of paramount importance for an efficient treatment and prevention of both disease complications and antimicrobial resistance.