Nasopharyngeal co-colonization and drug resistance patterns of potentially pathogenic bacteria in children attending Mulago assessment centre Pediatric Unit of Mulago National Referral Hospital, Uganda

Abstract

Background: The human nasopharynx is colonized by Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus. These bacteria may cause several diseases, especially in young children. There is limited data in Uganda on bacteria cocolonization of the nasopharynx and their antimicrobial drug resistance patterns after the introduction of the pneumococcal conjugate vaccine. The study sought to determine the nasopharyngeal co-colonization and drug resistance patterns of potentially pathogenic bacteria in children. Methods: A cross-sectional study was conducted from March to May 2019 at the Assessment Centre of Mulago National Referral Hospital, in children under five years old. 194 Children were randomly recruited and nasopharyngeal swab samples were collected, and then processed in Microbiology Laboratory for the isolation of S. pneumoniae, H. influenzae, Moraxella catarrhalis and S. aureus. The antimicrobial susceptibility tests were performed using disks diffusion method and E-test for minimum inhibition concentration. Results: The prevalence of nasopharyngeal co-colonization by the respiratory pathogens was 16.5 % (32/194) and the overall carriage rate was 46.4 % (90/194) for S. pneumoniae, 20.1% (40/194) for H. influenzae, 6.2% (12/194) for S. aureus and 7.2% (14/194) for M. catarrhalis. S. pneumoniae isolates were resistant to co-trimoxazole (100%), non- susceptible to penicillin G 100%) and Erythromycin (74.7%). H. influenzae were highly resistant to tetracycline (74.3%) and ampicillin (47.2%). Moraxella catarrhalis isolates were susceptible to the commonly used antibiotics except for ampicillin and co-trimoxazole. S. aureus was resistant to Penicillin (100%), Co-trimoxazole (92%), Erythromycin (75%) and Clindamycin (58.3%). Conclusion: The study reported a high prevalence of nasopharyngeal co-colonization by S. pneumoniae, H. influenzae, S. aureus and M. catarrhalis, though it was low compared to the study conducted in Eastern Uganda. It also reported a high prevalence of colonization by S. pneumoniae and a low prevalence of S. aureus and M. catarrhalis. All the bacteria species were highly resistant to co-trimoxazole and we also noticed a high resistance to erythromycin, penicillin, and ampicillin. Regular surveillance and awareness of antimicrobial drug resistance and the allocation of resources may play a significant role in slowdown the increasing drug resistance.