Abstract
Objective: To assess the prevalence, bacterial spectrum, and antibiotic resistance patterns of pathogens causing chronic suppurative otitis media (CSOM) in pediatric patients at a teaching hospital in Larkana.
Methodology: This descriptive cross-sectional study was conducted at CMC Teaching Hospital, enrolling 98 children (aged 5-15 years). Patients on recent antibiotic therapy were excluded. Aural swabs were cultured on Blood and MacConkey agar and identified by standard techniques. Antimicrobial susceptibility was determined using the Kirby-Bauer disc diffusion method. Data analysis was performed using SPSS 20.
Results: Bacterial growth occurred in 80% of samples, with Gram-negative (46.9%) and Gram-positive (33.7%) organisms. S. aureus (21.4%), E. coli (18.4%), Klebsiella spp. (17.3%), and P. aeruginosa (16.3%) were the most prevalent. Alarmingly high resistance to first-line agents was observed: S. aureus exhibited 42.86% penicillin resistance and 28.6% gentamicin resistance but 100% sensitivity to linezolid. E. coli showed 39-61% resistance to ampicillin and Amoxicillin-clavulanate, while carbapenems (imipenem/meropenem) and ceftazidime-avibactam demonstrated 94.44-100% sensitivity. Klebsiella spp. displayed 52.9% ampicillin resistance but 100% sensitivity to Ertapenem. P. aeruginosa exhibited 75-81% resistance to Ceftazidime and Gentamicin, while carbapenems and colistin achieved 100% efficacy. S. pneumoniae isolates showed 33.33% Penicillin resistance but full sensitivity to clindamycin and vancomycin.
Conclusion: These findings underscore widespread resistance to empiric therapies like β-lactams and aminoglycosides, contrasting with retained susceptibility to carbapenems, linezolid, and newer β-lactamase inhibitors.

Key words: Chronic suppurative otitis media, antibacterial resistance, S. aureus, E. coli, P. aeruginosa, Klebsiella spp. S. pneumoniae.