[Clinical features and antimicrobial resistance analysis of invasive non-typhoid Salmonella infection in children at Xi'an].

Objective: To investigate the clinical characteristics, serogroups and antimicrobial resistance of invasive non-typhoid Salmonella infection in children at Xi'an area. Methods: Retrospective cohort study. The clinical manifestations, treatment, prognosis, serogroups and antimicrobial drug resistance of 51 hospitalized children with invasive non-typhoid Salmonella infection confirmed by sterile body fluids or deep pus culture after operation at the Department of Infectious Diseases, the Department of General Surgery and the Department of Orthopedics in Xi'an Children's Hospital from January 2019 to December 2024 were retrospectively analyzed. The patients were divided into bloodstream infection group and local infection group according to the invasion site. The inflammatory markers, serogroups distribution and antimicrobial resistance were analyzed statistically by using Mann-Whitney U test and χ2 test. Results: Among the 51 children, there were 27 males and 24 females, with an onset age of 19 (14, 40) months. Nine cases (17%) were <1 year old, 28 cases (55%) under 1 - <3 years old, 7 cases (14%) under 3-<6 years old and 7 cases (14%) ≥ 6 years old. The onset time of 44 cases (86%) was from April to October. The diseases included 41 cases of bloodstream infection group, 10 cases of local infection group(including 6 cases of osteomyelitis involving the hip joint or humerus or pubis or navicular bone, 2 case of appendicitis with peritonitis and 2 cases of perianal or intra-abdominal abscess). The clinical manifestations were fever in 45 cases(88%), diarrhea and abdominal pain in 22 cases (43%), nausea and vomiting in 11 cases (22%), mesenteric lymphadenopathy in 4 cases (8%). Thirty-one cases (61%) were cured and twenty cases (39%) were improved by effective antibiotics treatment. White blood cell count in local infection group was significantly higher than that in bloodstream infection group (P<0.05).The serogroups of D (Salmonella enteritidis), C and B were the most prevalent among non-typhoid Salmonella isolates, accounting for 21 cases (41%), 10 cases (20%) and 10 cases (20%) respectively. Antibacterial drug sensitivity test showed that the sensitivity rates of piperaciratazobactam, ertapenem and imipenem all were 100% (51/51), those of ceftazidime, ceftriaxone and cefepime were 80% (41/51), 80% (41/51) and 86% (44/51), respectively. The drug resistance(including intermediate) rates of trimethoprim-sulfamethoxazole, aztreonam, ampicillin, ampicillin-sulbactam and ciprofloxacin were 24% (12/51), 16% (8/51), 57% (29/51), 57% (29/51) and 75% (38/51), respectively. There were no statistical differences in the drug resistance (including intermediate) rates of ceftazidime, ceftriaxone, cefepime, trimethoprim-sulfamethoxazole, ampicillin, ampicillin-sulbactam, aztreonam and ciprofloxacin between the bloodstream infection group and local infection group (all P>0.05). Conclusions: Invasive non-typhoid Salmonella infection in children at Xi'an area mainly occurred in infants younger than 3 years old. The main clinical manifestations are fever, abdominal pain and diarrhea.The serotypes are predominantly group D (Salmonella enteritidis). The third generation of cephalosporins is recommended as the drugs for empirical antibiotics treatment according to antimicrobial resistance and pediatric population.