Enteric fever, a serious bloodstream infection caused by Salmonella Typhi and Salmonella Paratyphi A, is contracted by consuming water or food that has been contaminated by the bacteria. Enteric fever continues to pose a significant health threat, particularly in low-income and middle-income countries. A groundbreaking study in Lancet Global Health, 'Estimating the subnational prevalence of antimicrobial resistant Salmonella enterica serovars Typhi and Paratyphi A infections in 75 endemic countries, 1990–2019: a modelling study', sheds light on the escalating prevalence of antimicrobial resistance (AMR) in these pathogens.
The study, conducted by the GRAM Typhoid Collaborators, an international team of researchers, utilised a Bayesian spatiotemporal modelling framework to estimate the percentage of multidrug resistance (MDR), fluoroquinolone non-susceptibility (FQNS), and third-generation cephalosporin resistance in Salmonella Typhi and Paratyphi A infections in 75 endemic countries from 1990 to 2019.
Key findings from the study include:
- A decline in MDR Salmonella Typhi in South Asia and Southeast Asia, contrasted with a concerning increase in sub-Saharan Africa, where the overall prevalence rose from 6·0% in 1990 to 72·7% in 2019.
- Rapid escalation of FQNS Salmonella Typhi in South Asia, reaching 95·2% in 2019, translating to 7·4 million infections in endemic countries.
- Low prevalence of third-generation cephalosporin-resistant Salmonella Typhi across most endemic areas, except for Pakistan, where resistance reached 61·0% in 2019.
- While MDR and cephalosporin resistance in Salmonella Paratyphi A remain low, a significant increase in FQNS took place, reaching 95·0% in 2019.