Phylogenetic Analysis and Public Health Implications of Salmonella Strains in Southwestern States of Nigeria Using InvA Gene Sequences

<i>Salmonella</i> is a significant public health concern in Nigeria causing foodborne illnesses. Genetic diversity and prevalence of <i>Salmonella</i> is poorly understood in Nigeria. This study assessed the occurrence of <i>Salmonella</i> in various poultry houses in Nigeria and explored the evolutionary relationships among the isolates by analysis on <i>invA</i> gene. A total number of 314 samples (feces, feed, dust, waters, and palm swab) were collected from 49 farms in Abeokuta (18), Ibadan (20) and Oshogbo (11). <i>Salmonella</i> was detected with a prevalence of 2.75% in Ogun, 6.0% in Osun and 5.71%, in Oyo States, respectively. The overall prevalence of <i>Salmonella</i> in poultry farms sampled was 15/314 (4.78%). Sequence analysis revealed two sequences 01 and 02 to have 99.59% and 89.04 homologies with sequence of Paratyphi serovar (LC320032) and Enteritidis serovar (LC318423) in GenBank, respectively. Sequence 01 clustered with <i>S.</i> serovar Enteritidis from the USA, whereas Sequence 02 formed a distinct clade near <i>S.</i> serovar Typhimurium from Egypt. These findings underscore the public health significance of <i>S. enterica</i> in Nigeria, particularly in relation to food animals. The study highlights the need for improved farm management practices, stringent food safety regulations, and robust surveillance systems to mitigate the risk of <i>Salmonella</i> outbreaks.