Molecular Characterisation of Enteric Bacteria in Diarrhoeic Stool Samples of Children Less than Five Years in Port Harcourt, Nigeria

Introduction: Diarrheal diseases remain a significant cause of morbidity and mortality among children under five years old, particularly in developing regions such as Port Harcourt, Nigeria. Aim: This study aimed to molecularly characterize bacteria in diarrheic stool samples from children less than five years in Port Harcourt. Methodology: Two hundred and seventy (270) Stool samples were collected from pediatric patients presenting with diarrhea at Rivers State University teaching hospital Port Harcourt from September 2023 to June 2024 for isolation and identification of bacteria causing childhood diarrhoea and ten (10) samples out of the 270 Stool samples collected were used for molecular analysis which involves 16S rRNA gene extraction, amplification using specific primers and sequencing. Data generated was used to create a phylogenetic tree to establish the origin and relationship between isolates. Results: The results reveal that out of the 270 samples, bacteria pathogens causing childhood diarrhoea was present in 98 at varying frequencies. They include: Escherichia coli 46 (17.0%), Salmonella species 20 (7.4%), Shigella species 16(5.9%), Yersinia species 10(3.7%) and Vibrio species 6(2.2%). There was no statistically significant association between sex and the prevalence of diarrhoea-causing bacterial pathogens (p = 0.7981) but there was a significant association found between age and the prevalence of bacterial pathogens (p < 0.0001). There was high level of multi drug resistance found amongst the isolates with all isolates having a 100% resistance to septrin and augumentin having a better performance index. Genetic analysis highlighted the presence of multiple strains as compared to 5 bacteria isolated using the conventional method of bacteria identification. The phylogenetic analysis revealed that all isolates evolved from a common ancestral lineage. Conclusion: This study shows the importance of comprehensive molecular surveillance and targeted intervention strategies to combat diarrheal diseases in young children in Port Harcourt. Understanding the genetic diversity and prevalence of pathogens can inform public health initiatives, including vaccination programs, sanitation improvements, and antimicrobial stewardship, aimed at reducing the burden of diarrheal illnesses and improving child health outcomes in the region.