Clinical and epidemiological characteristics of invasive non-typhoidal Salmonella disease in Ghana

BACKGROUND: Invasive non-typhoidal Salmonella (iNTS) disease remains a significant public health threat in sub-Saharan Africa (SSA). Although the disease is important, its clinical characteristics are not well described in literature. This study describes the clinico-epidemiological profile of iNTS disease in Ghana aiming to bridge important knowledge gaps and inform more effective management strategies. METHODS: The study spanned 8 years and utilized selected fever surveillance sites in Ghana. Patients with fever and/or history of fever for ≥ 3 consecutive days within the week prior to visit were approached and blood sample taken after consenting for investigations including blood culture. iNTS isolates were recovered using BACTEC blood culture, identified by Analytical Profile Index (API), sero-grouped using the Kauffmann-White scheme and confirmed by Illumina whole genome sequencing. Conditional logistic regression was used to assess associations between clinical and laboratory features and iNTS blood culture positivity in a 1:3 age-, sex-, and residence-matched case-control analysis. RESULTS: Of 271 blood-culture-derived bacterial pathogens, 15.5% (42/271) were identified as iNTS making it the second most common cause of bacteremia. iNTS disease exhibited seasonality with peak detections coinciding with the rainy seasons in Ghana. 23.7% (9/38) of iNTS isolates were multidrug-resistant (MDR), of which 5.3% (2/38) were extensively drug-resistant including resistance to ceftriaxone and ciprofloxacin. Several factors showed crude associations with iNTS disease; however, only anaemia retained its association after adjustment of other factors (aOR=2.41 p = 0.030). CONCLUSION: iNTS is a major cause of bloodstream infections with the highest burden in children under 5 years of age with susceptibility to the infection amplified by anaemia. The Salmonella serovars involved are increasingly becoming multidrug-resistant, including resistance to critical antibiotics.