The emergence of multidrug-resistant (MDR) Escherichia coli (E. coli), particularly E. coli sequence type ST131, is becoming a global concern. Commensal bacteria, an important reservoir of antibiotic resistance genes, facilitate the spread of such genes to pathogenic bacterial strains. The objective of the study is to investigate the fecal carriage of MDR E. coli and ST131 E. coli in community children in Southern Taiwan. In this prospective study, stool samples from children aged 0–18 years were obtained within 3 days of hospitalization from October 2013 to September 2014. Children with a history of underlying diseases, antibiotic treatment, or hospitalization in the 3 months before specimen collection were excluded. E. coli colonies were selected and tested for antimicrobial susceptibility, and O25b-ST131, multilocus sequence typing, and blaCTX-M gene groups were detected. Among 157 E. coli isolates, the rates of nonsusceptibility to ampicillin, amoxycillin + clavulanate, trimethoprim–sulfamethoxazole, and cefazolin were 70, 65.6, 47.1, and 32.5%, respectively. Twenty-nine (18.5%) isolates were nonsusceptible to ciprofloxacin. MDR E. coli accounted for 58 (37%) of all isolates. Thirteen (8.3%) isolates produced extended-spectrum β-lactamase (ESBL). Furthermore, 26 (16.6%) and 13 (8.3%) isolates were O25b and ST131 positive, respectively. Five (38.5%) of the 13 ESBL-producing E. coli belonged to blaCTX-M group 9, among which were CTXM-14 and 4 (80%) were O25b–ST131 positive. Compared with the non-ESBL and ciprofloxacin-susceptible groups, the ESBL and ciprofloxacin-nonsusceptible groups showed significantly higher rates of O25b–ST131 positivity. The prevalence of the fecal carriage of nonsusceptible E. coli in children was high; among these E. coli, 37% were MDR, 18.5% were nonsusceptible to ciprofloxacin, and 8.3% produced ESBL. O25b–ST131 was the most common ESBL-producing E. coli clonal group present in the feces of children, and the ESBL and ciprofloxacin-nonsusceptible groups showed significantly higher rates of O25b–ST131 positivity.

This study investigated whether the appropriate antibiotics therapy affects the fecal excretion time in pediatric salmonellosis of different severities and explored the factors associated with the fecal excretion time of nontyphoid Salmonella. Between 2012 and 2017, admitted children with nontyphoid salmonellosis who consented to receive consecutive stool cultures every 4-7 days until 2 consecutive negative results were obtained were enrolled. Patients were stratified into no, appropriate (bacteremia or severe patients receiving antibiotics active in vitro), and inappropriate antibiotics (patients with mild or moderate severity receiving antibiotics or severe receiving antibiotics resistant in vitro) therapy groups. A previously proposed severity score was used to classify the patients into severe, moderate, and mild severity classes. The demographics, clinical manifestations, laboratory data and severity were compared among the groups. To explore the factors associated with the fecal excretion time of nontyphoid Salmonella, univariate and multivariate analyses were performed using linear regression analysis. This study enrolled 126 children with nontyphoid salmonellosis; 58 and 18 in the mild and severe classes, respectively. The no, appropriate and inappropriate antibiotics therapy groups comprised 69, 24 and 33 patients, respectively. The mean fecal excretion time was 12.17 days. The appropriate antibiotics therapy group had comparable fecal excretion time with that of no antibiotics group. Age <1 year, increased white blood cell count, decreased hemoglobin, and inappropriate antibiotics therapy significantly prolonged fecal excretion time in univariate analysis (p < 0.05). The multivariate analysis showed that inappropriate antibiotics therapy and decreased hemoglobin significantly prolonged the fecal excretion time. Inappropriate antibiotics therapy and decreased hemoglobin prolong the fecal excretion time of nontyphoid Salmonella, whereas appropriate antibiotics therapy does not. Continuous monitoring of antibiotic resistance and judicious use of antibiotics in children with nontyphoid salmonellosis are necessary.