Prevalence and Molecular Characterization of Salmonella spp. Isolated from Patients’ Blood Specimen in Federal Medical Center, Umuahia

Abstract

Background: Bloodstream infections caused by Salmonella spp. remain clinically important in settings where sanitation and healthcare infrastructure are limited. This study assessed the prevalence, serotypes, and molecular identity of Salmonella isolates recovered from patients’ blood specimens at Federal Medical Center, Umuahia, Abia State, Nigeria. Methods: Whole-blood specimens were collected from 470 patients and cultured in blood-culture media. Suspected isolates were assessed by culture morphology, Gram staining, biochemical methods, serological testing, and 16S rRNA sequencing. Antimicrobial susceptibility was evaluated by the disk diffusion method. Results: Of 470 blood specimens cultured, 88 were initially culture-positive for suspected organisms, corresponding to 18.7%. Among 74 samples subcultured, 22 yielded bacterial growth, representing 29.7% of the subcultured samples. Molecular analysis identified four Salmonella enterica strains corresponding to Typhi, Paratyphi A, and the ARA7 isolate reported in the manuscript. The 25–34-year age group accounted for the largest share of positive cases reported, while more positive cases were observed among males than females. The study also reported variation in positivity across the March–August sampling period. Conclusion: The findings document blood-culture positivity and molecularly confirmed Salmonella strains among patients investigated at Federal Medical Center, Umuahia. Blood culture supported phenotypic detection, while 16S rRNA sequencing provided molecular confirmation of the recovered isolates. These findings provide facility-specific data for the study population and period.