Detection characteristics and antimicrobial resistance profiles of Salmonella spp. isolated from fecal cultures of inpatients at a maternal and child healthcare hospital in Shenzhen: a 5-year retrospective study

ABSTRACT Salmonella spp. remain an important cause of bacterial gastrointestinal infection, but local data from maternal and child healthcare hospitals remain limited. This retrospective study analyzed Salmonella spp. isolated from fecal cultures of inpatients at Longgang District Maternity and Child Healthcare Hospital of Shenzhen City from 2021 to 2025. Fecal specimens were processed using routine selective culture procedures; isolates were identified with the VITEK 2 Compact system, with VITEK MS confirmation when required, and antimicrobial susceptibility was interpreted according to Clinical and Laboratory Standards Institute (CLSI) M100, 35th edition. Annual positivity and non-duplicate isolation rates were compared using Pearson χ 2 tests. A total of 106 non-duplicate isolates were recovered, including 98 from pediatric inpatients. Annual positivity and non-duplicate isolation rates differed significantly across the 5-year study period (both P < 0.001) and were highest in 2025. Among pediatric cases, children aged 1–3 years accounted for 79.6%, with the 12 to <24-month group accounting for 52.0%. Resistance was high to ampicillin (76.7%), ampicillin/sulbactam (63.3%), trimethoprim-sulfamethoxazole (46.6%), and ceftriaxone (36.9%). Resistance to ciprofloxacin and levofloxacin was 12.5% and 14.8%, respectively, although intermediate rates were high. Most isolates remained susceptible to piperacillin/tazobactam and carbapenems. These findings show a concentration of laboratory-detected Salmonella among children aged 1–3 years, particularly those aged 12 to <24 months, and substantial resistance to several commonly used agents, supporting continued local surveillance and susceptibility-guided antimicrobial use. IMPORTANCE Salmonella spp. remain an important bacterial cause of gastrointestinal infection in children, but local data from maternal and child healthcare hospitals are limited. This 5-year retrospective study describes the detection characteristics and antimicrobial resistance profiles of Salmonella spp. isolated from fecal cultures of inpatients in a maternal and child healthcare hospital in Shenzhen, China. The findings show that Salmonella isolates were mainly recovered from young pediatric patients and exhibited high resistance to several commonly used antimicrobial agents, including ampicillin, ampicillin/sulbactam, trimethoprim-sulfamethoxazole, and ceftriaxone, while reduced susceptibility to fluoroquinolones was also observed. These results provide institution-specific evidence for empirical treatment decisions, antimicrobial stewardship, and continued surveillance of enteric bacterial pathogens in pediatric and maternal-child healthcare settings.