Nasopharyngeal bacterial isolates, their antibiotic susceptibility profile, and factors associated with asymptomatic carriage rate among primary school children in Dessie Town, Northeast Ethiopia in 2023: a multi-center cross-sectional study

Nasopharyngeal bacterial carriage is the primary stage for disease transmission. It is a serious public health issue affecting school-age children, with increased community-acquired respiratory tract infections. The problem has been worsening when the carriage is due to multi-drug resistant (MDR) bacterial isolates. However, the real magnitude of the problem is not well known. Thus, the aim of this study was to determine the asymptomatic nasopharyngeal bacterial carriage, antimicrobial resistance pattern and associated factors among primary school children in Dessie Town, Northeast Ethiopia. An institution-based multi-center cross-sectional study was conducted among 388 randomly selected children between April 1 and June 30, 2023. A semi-structured questionnaire was used to collect socio-demographic data. The nasopharyngeal swab sample was aseptically collected and then inoculated onto MacConkey agar, chocolate agar, Mannitol salt agar, and blood agar. The bacterial growths were characterized using Gram staining and biochemical tests. A modified Kirby-Bauer disk diffusion method was used for antimicrobial sensitivity testing. SPSS version 25 was used for data analysis. Logistic regression analysis was computed to identify associated factors, and variables with a P -value < 0.05 were statistically significant. The overall prevalence of nasopharyngeal bacterial carriage was 40.7% (158/388). The most predominant isolates were Staphylococcus aureus 32.2% (51/158), followed by coagulase negative staphylococcus (CoNs) 24.7% (39/158), and Streptococcus pneumoniae 14.5% (23/158). The overall prevalence of MDR was 44.9%, with K. oxytoca (100%), K. pneumonia (95%), and CoNs (71.8%) showing the highest level of MDR. Age group of children 6–10 years ( P = 0.017), number of rooms ≤ 2 per house ( P < 0.001), family size of 2 to 5 members ( P < 0.001) and number of students ≥ 41 in the classroom ( P < 0.001) were significantly associated risk factors for nasopharyngeal bacterial carriage. Asymptomatic nasopharyngeal bacteria carriage in children is an alarm for community-acquired infection. The overall multidrug resistance was high. The risk of bacterial carriage increased with larger family sizes, the number of rooms in the house, and the number of students per class. Longitudinal follow-up studies would be helpful for better understanding the infection risk in bacterial pathogens. Further molecular techniques to characterize isolates and determine their pathogenic nature are important. Not applicable.