Clinical Characteristics and Antimicrobial Resistance of Non-typhoidal <i>Salmonella</i> Enteritis in Infants: A Single-Center Study in Chengdu, West China, 2018 - 2023

Abstract

Background: Non-typhoidal Salmonella (NTS) enteritis is a leading cause of bacterial gastroenteritis in infants, a particularly susceptible population. Despite the substantial disease burden, data on the epidemiology and antimicrobial resistance of NTS enteritis in infants remain limited, particularly regarding factors associated with multidrug-resistant (MDR) infections. Objectives: The primary outcome was clinician-driven antibiotic escalation to cefoperazone-sulbactam, defined as a treatment change based on predefined severity criteria and physician judgment rather than a purely biological endpoint. We aimed to identify factors associated with this escalation in infants with NTS enteritis. Secondary outcomes included epidemiological characteristics, clinical features, and antimicrobial resistance patterns. Accordingly, we investigated these outcomes among infants with NTS enteritis in Chengdu, the largest city in West China. Methods: This retrospective analysis included 229 hospitalized infants diagnosed with NTS enteritis between January 2018 and December 2023. Demographic, clinical, laboratory, and microbiological data were collected and analyzed. Results: The annual detection rate of NTS peaked in 2020 and remained high, with a significant summer–autumn peak that was positively correlated with monthly average temperature (r = 0.847, P < 0.001). Infants aged < 6 months had significantly lower fever levels than those aged 7 - 12 months (P ≤ 0.001). In contrast, platelet counts decreased with age. Salmonella Typhimurium was the predominant serotype (76.42%). The overall antimicrobial resistance rate was 78.6%, and the MDR rate was 22.2%. Resistance was highest to ampicillin (> 60%) and lowest to cefoperazone-sulbactam (2.6%). Urban residence (OR = 0.436), stool frequency (OR = 2.146), and MDR strains (OR = 2.731) were independently associated with escalation of antibiotic therapy to cefoperazone-sulbactam. Conclusions: NTS enteritis in infants in West China showed marked seasonal variation influenced by temperature, with Salmonella Typhimurium as the dominant serotype and high resistance to traditional first-line antibiotics (ampicillin, trimethoprim-sulfamethoxazole, ciprofloxacin, and cefotaxime). Rural residence, stool frequency, and MDR were associated with escalation of antibiotic therapy. Enhanced resistance surveillance and appropriate antibiotic use are urgently needed. The in vitro susceptibility to cefoperazone-sulbactam is promising; however, clinical outcome data are lacking to support its preferential use.