Change of serotype pattern of Group D non-typhoidal Salmonella isolated from pediatric patients in southern Taiwan

Abstract

Background and purpose: Group D non-typhoidal Salmonella infection is increasing in Taiwan. This study aimed to investigate the changing serotypes and antibiotic resistance of childhood group D Salmonella infection.

Methods: From 1998 through 2004, children (<16 years) infected with group D Salmonella were retrospectively reviewed. Demographic data, clinical and laboratory features, and risk factors of bacteremia were analyzed. Enrolled patients were classified as acute gastroenteritis with bacteremia (Group I) and acute gastroenteritis without bacteremia (Group II). The minimal inhibitory concentrations were determined by agar dilution method. Genotyping was performed by use of pulsed-field gel electrophoresis (PFGE).

Results: Eighty one children (Group I, n = 15; Group II, n = 66) were enrolled with a mean (+/- standard deviation) age of 3.1 +/- 2.6 years. Group I patients were younger and had a longer duration of fever prior to admission (> or =5 days, 40% vs 9.2%; p=0.003) and total fever duration (8.3 vs 4.1 days, p<0.001) than Group II. Salmonella enterica serotype Enteritidis (80%) was the most common serotype, followed by Salmonella Panama (7%). The antibiotic resistance rates of S. Enteritidis were: tetracycline (36.5%), trimethoprim-sulfamethoxazole (25.4%), ampicillin (14.3%), and chloramphenicol (12.7%). S. Panama was associated with a higher rate of bacteremia. All strains were susceptible to quinolone and third-generation cephalosporins. PFGE study showed a single genotype of S. Enteritidis and diverse genotypes of S. Panama circulating in the area.

Conclusions: S. Enteritidis was the predominant serotype of group D Salmonella that caused pediatric infection in southern Taiwan during the study period from 1998 to 2004. S. Panama is associated with higher rates of bacteremia and antimicrobial resistance.