Bacteriological Profile, Antibiotic Susceptibility Patterns, and Genotypic Characterization of Drug-Resistant Organisms in Chronic Suppurative Otitis Media at a Tertiary Care Hospital

Background Chronic suppurative otitis media (CSOM) is a major cause of preventable hearing loss, particularly in developing countries. The emergence of multidrug-resistant pathogens has made empirical antibiotic therapy increasingly challenging. This study aimed to investigate the bacteriological profile, antimicrobial resistance pattern, and genotypic characteristics of drug-resistant bacterial isolates from patients with CSOM in a tertiary care setting. Methodology A hospital-based cross-sectional descriptive study was conducted among 111 patients with CSOM over one year. Ear discharge specimens were subjected to Gram staining, bacterial culture, biochemical identification, antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method (HiMedia Laboratories Pvt. Ltd., Mumbai, India) according to Clinical and Laboratory Standards Institute (CLSI), phenotypic detection of resistant organisms, and polymerase chain reaction (PCR) for mecA gene detection in methicillin-resistant Staphylococcus aureus (MRSA). Associations between culture positivity and demographic or clinical variables were analyzed using the Chi-square test. Results Among 111 participants, 68 (61.3%) were females, and 101 (91.0%) were adults. Culture positivity was observed in 90 (81.1%) patients, while 21 (18.9%) showed no bacterial growth. Gram-negative bacilli constituted 62 (68.9%) of isolates, with Pseudomonas aeruginosa being the predominant pathogen (50, 45.1%), followed by S. aureus (22, 19.8%) and Klebsiella pneumoniae (9, 8.1%). Meropenem demonstrated 100% sensitivity against P. aeruginosa and K. pneumoniae, while linezolid showed 100% sensitivity against S. aureus. MRSA accounted for 14/22 (63.6%) S. aureus isolates, and all MRSA isolates (14/14, 100%) were positive for the mecA gene by PCR, confirming genotypic methicillin resistance. Extended-spectrum β-lactamase (ESBL) production was detected in 12/59 (20.3%) Gram-negative isolates. Culture positivity was significantly associated with gender (P = 0.040) and age (P < 0.001) but not with complications (P = 0.617). Conclusions P. aeruginosa remains the predominant pathogen causing CSOM, with a substantial burden of multidrug resistance, including MRSA and ESBL-producing organisms. Routine culture, antimicrobial susceptibility testing, and molecular detection of resistance genes are essential for guiding appropriate therapy, optimizing antimicrobial stewardship, and improving clinical outcomes in CSOM.