METHODS: This cross-sectional study involved 91 ear swab specimens obtained from patients clinically diagnosed with active CSOM. Swabs were cultured for microbial identification according to a standard protocol. We performed antibiotic susceptibility testing, using the modified Kirby-Bauer disc diffusion method, and the diameter of the inhibition zone was interpreted based Clinical Laboratory Standards Institute guidelines.
RESULTS: Microbial growth was seen in 85 (93.4%) samples, but 6 (6.6%) samples had no growth. Among the samples with growth, 63 (69.2%) were monomicrobial, 13 (14.3%) were polymicrobial, and 9 (9.9%) were of mixed growth with more than three microorganisms. The most common bacteria isolated was Pseudomonas aeruginosa (32.6%) followed by Staphylococcus aureus (16.9%) and Klebsiella spp. (5.6%). The most sensitive antibiotics against P aeruginosa were ceftazidime, meropenem, piperacillin-tazobactam, and cefepime. S aureus showed the highest sensitivity toward rifampin, cefoxitin, and fusidic acid.
CONCLUSIONS: The bacteriological profile of CSOM showed a high prevalence of P aeruginosa, followed by S aureus and Klebsiella spp. with different distributions in different age groups. We observed a declining pattern of their antibiotic sensitivity. It is important to be aware of the current trend of the bacteriological profiles and to revise the antibiotic regime according to both the sensitivity and age groups.Level of Evidence: NA.