Comparative Efficacy of Ceftriaxone and Cefotaxime Klebsiella pneumonia Isolates Causing Otitis Media in Children in Diyala, Iraq

Abstract

Background: Otitis media is one of the most frequent infections during childhoodin klebsiella pneumonia isolates causing Otitis Media, especially in relation to recurrent and complicated cases of otitis media.

Methods: Baqubah Teaching Hospital, Al-Batool Teaching Hospital, and Al-Khalis General Hospital in the Diyala Governorate of Iraq were selected as the study sites for a prospective cross-sectional study conducted d between September 2024 and January 2026. Middle ear samples were collected, and after standard microbiologic methods, and K. pneumoniae was identified using the VITEK-2 system. Antimicrobial susceptibility testing for ceftriaxone and cefotaxime was performed using Kirby-Bauer disk diffusion and E-test methods were employed, in accordance with CLSI 2025. ESBL production was detected with modification of the combination disk method.

Results: Positive cultures were found in 82.8% (265 of 320) of children.  K. pneumoniae was found in 78 of these isolates (29.4% of positive cultures, 24.4% of all samples) with a mean age of 4.2 ± 2.8 years. 71.8% were under 5 years of age. 59 (75.6%) were confirmed ESBL producers. Among the resistant isolates, ceftriaxone and cefotaxime showed MIC₅₀/MIC₉₀ values, with cefotaxime having a statistically significantly lower MIC (p = 0.009). In the checkerboard synergy assay, 80.8% (63 of 78) of isolates showed synergy (FICI ≤ 0.5) with cefotaxime and avibactam in contrast to 38.5% with ceftriaxone and tazobactam (p < 0.001). Regression analysis found prior hospitalization within 3 months (OR = 5.12, 95% CI: 2.78-9.43, p < 0.001), prior cephalosporin use (OR = 6.34, 95% CI: 3.45-11.65, p < 0.001), and recurrent otitis media (OR = 3.87, 95% CI: 2.12-7.06, p < 0.001) to be statistically significant independent resistance risk factors.

Conclusion: Due to the high prevalence of ESBL, monotherapy with ceftriaxone or cefotaxime has been shown to be ineffective against the majority of K. pneumoniae isolates from pediatric otitis media in Diyala. Even though cefotaxime has the lowest MIC against the resistant strains, however, the combination of cefotaxime with avibactam demonstrated strong synergistic activity paraphrasing.