Analysis of bacterial etiology of the outpatients with infectious diarrhea in the Children′s Hospital Capital Institute of Pediatrics

Abstract

Objective To analyze the bacterial etiology and drug resistance of pathogens from the outpatients with acute infectious diarrhea in the Children′s Hospital Capital Institute of Pediatrics. Methods The children with acute infectious diarrhea in the outpatient department of our hospital were randomly enrolled in the period of August 2017 to July 2018. Enteric pathogenic bacteria were cultured and isolated from the fresh stool specimens. The serum of Salmonella spp were identified while five types of diarrheagenic Escherichia coli were detected by PCR method. Antibiotic susceptibility of Salmonella spp and diarrheagenic Escherichia coli were tested by Kirby-Bauer disk diffusion method.Chi-square or Fisher exact test was done for statistical analysis. Results Of the 356 stool specimens, 103 strains of 6 pathogenic bacterial species were detected. The positive rate was 27.8% (99/356), and 2 strains were detected in four stool samples. The isolation rate of Salmonella spp, which was the highest in this study, was 10.7% (38/356). The isolation rate of Staphylococcus aureus, diarrheagenic Escherichia coli and Pseudomonas aeruginosa were 8.4% (30/356), 5.6% (20/356) and 3.7% (13/356), respectively. No Shigella spp strain was isolated. Salmonella enteritidis and Salmonella typhimurium were the dominant serotype for 38 Salmonella spp stains with the isolation rate of 63.2% (24/38). Each 10 Enteropathogenic Escherichia coli and 10 Enteroaggregative Escherichia coli isolates were detected among the diarrheagenic Escherichia coli. Enterohemorrhagic Escherichia coli, Enteroinvasive Escherichia coli and Enterotoxigenic Escherichia colistrain was not found in this study. The resistant rates of Salmonella spp to ampicillin and ceftriaxone were 52.6% (20/38) and 13.2% (5/38), while the diarrheagenic Escherichia coli were 11/20 and 1/20, respectively. Three diarrheagenic Escherichia coli isolates produced extended spectrum beta-lactamase. Conclusions Salmonella spp was the major bacterial pathogen among the outpatients with infectious diarrhea in the hospital. The study indicated that the infection ratios of Staphylococcus aureus, diarrheagenic Escherichia coli and Pseudomonas aeruginosa increased. Shigella spp was no long the main pathogenic agent. The resistant rates of Salmonella spp and diarrheagenic Escherichia coli to ampicillin were high, but low resistant rates to ceftriaxone were found among these two kinds of bacteria. The third-generation cephalosporins should be the first choice for the treatment of childhood bacterial diarrhea. Key words: Diarrhea; Salmonella; Escherichia coli; Drug resistance,Bacterial; Child