TITLE:
Stool Culture Confirmed Salmonella Carriage, Plasmodium Infection, Associated Risk Factors, and Multidrug Resistance Patterns among Widal-Positive Patients in Yaoundé, Cameroon
AUTHORS:
Raissa Estelle Guiamdjo Simo, Hortense Kamga Gonsu, Anicette Betbeui Chafa, Wilfred Fon Mbacham
KEYWORDS:
Salmonella spp., Plasmodium spp., Coinfection, Widal Test, Multidrug Resistance, Cameroon
JOURNAL NAME:
Open Journal of Medical Microbiology,
Vol.16 No.3,
August
5,
2026
ABSTRACT: Typhoid fever and malaria remain major public health concerns in tropical regions where both infections are endemic, largely due to overlapping clinical manifestations such as fever, headache, diarrhoea, vomiting, and chills, which complicate accurate diagnosis. The Widal test, although widely used in resource-limited settings, is limited by poor specificity and frequent cross-reactivity with non-salmonella conditions. This limitation can be attributed to non-specific polyclonal B-cell activation induced by Plasmodium spp. infection, which can result in false-positive Widal test outcomes in cases of co-infection with Salmonella spp., leading to misdiagnosis, inappropriate treatment, and the emergence of antimicrobial resistance. This study aimed to determine the prevalence of stool culture confirmed Salmonella spp. carriage, Plasmodium spp. infection and co-infection among Widal-positive patients, identify associated risk factors, and assess multidrug resistance (MDR) patterns of Salmonella isolates in Yaoundé. A cross-sectional study was conducted from September 2022 to April 2023 across five hospitals. Participants presenting with symptoms suggestive of typhoid fever and/or malaria who were tested positive to the Widal test were enrolled by convenience sampling. Sociodemographic and clinical data were collected using structured questionnaires. Malaria diagnosis was confirmed by microscopy of thick blood smears, while stool samples were cultured on Hektoen enteric agar for Salmonella isolation, followed by identification using the API 20E system and serotyping by slide agglutination. Antibiotic susceptibility testing was performed using the disk diffusion method (CASFM 2023 guidelines), and MDR indices were calculated. Among 277 Widal-positive participants, stool culture confirmed Salmonella spp. carriage was detected in 23 (8.4%), Plasmodium spp. in 113 (40.8%), and concurrent carriage of both in 12 (4.4%). Of the 23 Salmonella isolates, only 7 (30.4%) were typhoidal serovars (S. Paratyphi B); the remaining 16 (69.6%) were non-typhoidal serovars. Notably, S. Typhi was not recovered. A significant association was found between water source and Salmonella spp. carriage (p Salmonella isolates were non-typhoidal, underscoring the need for improved diagnostic strategies beyond the Widal test to reduce misdiagnosis and inappropriate antibiotic use.