Etiology of otitis media, antimicrobial susceptibility pattern and risk factors among under five children in Jimma, Oromia, Southwest Ethiopia

Abstract Otitis media (OM) represents a major public health challenge and one of the most frequent causes of pediatric consultations worldwide. Although previous studies have investigated the prevalence of OM and antimicrobial resistance in Ethiopia, most were conducted before the widespread implementation of Haemophilus influenzae type b (Hib) and pneumococcal conjugate vaccines or included all age groups rather than focusing specifically on under five years children. Continuous surveillance of the bacterial etiology spectrum and evolving patterns of bacterial antibiotic resistance is crucial to inform evidence-based prevention and treatment strategies. Therefore, this study was aimed to determine the etiology of bacterial OM, the distribution of pneumococcal serotypes, and the susceptibility pattern of isolates among under five children in Jimma city, Jimma, Oromia, Southwest Ethiopia. A cross-sectional study was conducted among 237 children suspected of having OM in Jimma City from March 01, 2023 to February 26, 2024. Interviewer based questionnaire was used to collect data. Middle ear discharges were collected, cultured and isolates were identified. Susceptibility tests were done using disk diffusion method. S. pneumoniae isolates from culture were extracted using alkaline lysis DNA extraction method as previously described. Amplification of autolysin ( lytA ) gene of S. pneumoniae was performed using primers lytA-F: 5’ CAACCGTACAGAATGAAGCGG-3’ and lytA-R; 5’TTATTCGT G CAATA CTCGTGCG-3’. Serotyping using oligonucleotide primers used in 41 conventional multiplex PCR assay. Data were summarized and presented in frequency table and while variables significant at p < = 0.25 in bivariate logistic regression were used in multivariable model to identify independent associations. Variables in the multivariable model were considered as significant at P < 0.05. Results were then reported as crude odds ratio (COR) and adjusted odds ratio (AOR) with 95% confidence interval (CI). The prevalence bacterial OM was 65.4% (155/237). Of the total growth, 13.5% (32/237) had polymicrobial growths while 52% (123/237) had monomicrobial growth. Of total the bacterial isolates, 58.7% (111/189) were Gram positive bacteria isolates while Gram negatives bacteria were 41.3% (78/189). Among the total isolates, the most frequently isolated species were S. aureus 54% (102/189), P. mirabilis 8.5% (16/189), and E. coli 5.3% 910/189). Prevalence of multidrug resistant (MDR) bacteria was 47.6% (90/189). Six serotypes/serogroups were identified among the S. pneumoniae isolates, with 66.7% (4/6) of them being non-vaccine serotypes. Rural individuals had a lower risk of OM ( p = 0.018), whereas those having history of allergies had a threefold higher risk of being positive ( p = 0.006). The prevalence of OM was high with alarming MDR isolates. Residence and history of allergies were significant predictors of OM. Periodic surveillance of bacterial OM and drug resistance patterns as well as risk factor reduction is warranted.