Analysis of foodborne salmonellosis serotypes and drug resistance in children in Chenzhou City of China from 2017 through 2022.

Background: is a significant pathogens of foodborne illness. The widespread use of antibiotics in clinical practice and animal husbandry has resulted in increasing drug resistance of . In this study, we examined the serotype distribution and drug resistance of in pediatric patients with diarrhea in Chenzhou City to provide a basis for the scientific control and rational use of antibiotics in clinical practice in relation to .

Methods: Stool . were collected from patients younger than 18 years of age who met the definition for foodborne illness at two sentinel hospitals from 2017 through 2022 tested , and a descriptive analysis of the epidemiologic characteristics. strains isolated from the stool underwent serology and drug-sensitivity tests. The following 14 antibiotics were used for the drug-sensitivity tests: ampicillin (AMP), ampicillin/sulbactam (AMS), cefazolin (CFZ), cefoxitin, cefotaxime, ceftazidime, imipenem (IPM), tetracycline (TET), nalidixic acid, ciprofloxacin, chloramphenicol (CHL), gentamicin, trimethoprim/sulfamethoxazole (SXT), and azithromycin.

Results: Samples from 1,263 pediatric with diarrhea, and was detected in 221 (17.5%) of these patients. Positive test results were principally observed in the second and third quarters of each year, accounting for 21.1% and 19.6% of the cases, respectively. The infection rates of infants aged less than 12 months and toddlers aged 1-3 years with diarrhea were the highest at 21.3% and 17.8%, respectively. The 221 strains were divided into 32 serotypes, of which Typhimurium ( Typhimurium) was the dominant strain (79.2%). The resistance rates to TET (86.9%), AMP (75.6%), AMS (58.4%), CFZ (55.7%), CHL (54.3%), and SXT (45.2%) predominated, and the differences in the drug-resistance rates to 1-, 2-, and 3-generation cephalosporins were high (2.3-55.7%). Only 0.9% of the strains were resistant to IPM. The multidrug resistance (MDR) rate was 76.5% (169/221), and 48.9% (108/221) of the strains were resistant to five or more classes of antibiotics, of which the most common drug-resistance profile was AMP-AMS-TET-CHL-CFZ-SXT, accounting for 10.9% of Salmonella strains (24/221).

Conclusions: Foodborne salmonellosis tended to occur during the summer and autumn in children, and infants and toddlers were more likely to develop salmonellosis than children in the other age groups. The dominant serotype was . Typhimurium. The drug-resistance rate of the tested strains was high, and the MDR problem was severe. We recommend that in the treatment of salmonellosis, antibiotics be selected rationally based on the drug-resistance status of local resistance situation to ensure safety and efficacy.