Epidemiological trends in serotypes distribution and antimicrobial resistance in Salmonella from humans in Taiwan, 2004-2022

Salmonella, a zoonotic pathogen, significantly impacts global human health. Understanding its serotype distribution and antimicrobial resistance is crucial for effective control measures and medical interventions.

We collected Salmonella isolates and demographic data from Taiwanese hospitals between 2004 and 2022, analyzing their serotypes and antimicrobial susceptibility.

Among 40,595 isolates, salmonellosis predominated in children aged 0-4 (61.2%) years and among males (55.2%). Males also showed higher rates of extraintestinal infections (18.1% vs 16.0%, P <0.001), particularly, in the ≥65 years age group (52.4%). The top five serovars were S. Enteritidis (32.8%), S. Typhimurium (21.7%), S. Newport (6.2%), S. Stanley (4.7%), and S. Anatum (4.0%). Notably, S. Enteritidis prevalence increased from 23.9% (2004-2005) to 43.6% (2021-2022). Antimicrobial resistance was high, with a 51.6% multidrug resistance (MDR) rate. Disturbingly, MDR rates exceeded 90% in serovars Albany, Schwarzengrund, Choleraesuis, and Goldcoast. Resistance to key therapeutic agents, azithromycin, cefotaxime, and ciprofloxacin, exhibited concerning upward trends, and the surge in cefotaxime and ciprofloxacin resistance was closely linked to the emergence and spread of MDR S. Anatum and S. Goldcoast clones.

Prioritizing control measures against S. Enteritidis and closely monitoring the prevalence and spread of MDR clones are imperative to mitigate Salmonella infections in Taiwan.