Serotype Distribution and Antimicrobial Resistance of Salmonella in Korea Between 2018 and 2022

Salmonella is one of the main pathogens causing food-borne infectious diseases. We investigated the serotype distribution and antimicrobial resistance of Salmonella isolates in Korea obtained between 2018 and 2022.

We studied 965 Salmonella isolates from nine university hospitals across Korea. Serotypes were determined following the Kauffmann-White scheme, and antimicrobial susceptibility tests were performed using Sensititre KRCDC2F susceptibility testing plates.

Of the 965 isolates, 732 (75.9%) were isolated from stool specimens, and 233 (24.1%) were isolated from blood specimens. We identified 58 different serotypes. The five most frequent serotypes detected were S. serovar Enteritidis (N=207; 21.5%), S. serovar I 4,[5],12:i:- (N=200; 20.7%), S. serovar Infantis (N=88; 9.1%), S. serovar Bareilly (N=77; 8.0%), and S. serovar Typhimurium (N=69; 7.2%). The 10 most common serotypes accounted for 79.4% of all isolates. The resistance rates to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, cefotaxime, and ceftriaxone were 33.2%, 11.1%, 8.2%, 8.6%, and 8.3%, respectively. Although only 3.0% of Salmonella isolates were resistant to ciprofloxacin, the intermediate resistance rate was 32.8%. We observed ciprofloxacin non-susceptibility (93.7%) in S. Enteritidis, ciprofloxacin resistance (83.3%) in S. serovar Paratyphi A, and extensive drug resistance (10.0%) in S. serovar Typhi. The overall rates of multidrug and extensive drug resistance were 6.2% (N=60) and 2.0% (N=19), respectively.

Continuous monitoring of Salmonella serotypes for antimicrobial resistance is necessary for appropriate patient management.