A molecular comparative study of intestinal colonization with between pediatric inpatients and outpatients of different age groups.

Currently, () is one of the leading causes of death from infectious diseases worldwide. Our aim in this study was to investigate and compare the molecular epidemiology and antibiotic resistance of colonizing the intestinal tract of pediatric inpatients and outpatients of different age groups. We analyzed stool samples from 1,300 patients at a children's hospital in Shenzhen, China. After culturing , we used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to identify the strains. In addition, we performed antimicrobial susceptibility testing on isolated strains as well as pheno- and genotypic characterization by PCR. was detected in 104 out of 1,300 (8.0%) patients, including 20 out of 1,300 (1.5%) patients with methicillin-resistant (MRSA). MRSA accounted for 19.2% of the isolates. The resistance rates of strains to penicillin, erythromycin, clindamycin, levofloxacin, and moxifloxacin were 83.7%, 34.6%, 31.7%, 3.9%, and 3.9%, respectively. None of the strains showed resistance to linezolid, daptomycin, tigecycline, vancomycin, or tetracycline. One hundred fou strains of revealed that 49.0% (51/104) harbored enterotoxin genes, and most enterotoxin-positive strains carried only one gene type (90.2%, 46/51), while a minority carried two gene types (9.8%, 5/51). Besides, a total of 29 sequence types (STs) were identified with the three most prevalent STs: ST45, ST188, and ST6, accounting for 12.5%, 12.5%, and 9.6%. We found that the molecular characteristics of in intestinal colonization of children have regional differences. To provide a theoretical basis for the prevention and control of infections, increased surveillance of local resistance and molecular epidemiological characteristics is needed.IMPORTANCEThis study assessed the clinical and molecular epidemiology of in pediatric patients at a children's hospital in Shenzhen, South China by means of screening stool samples for pheno- and genotypic characterization for carriage of . Of 1,300 fecal samples screened, 104 (8.0%) were positive for with 19.2% methicillin-resistant . The resistance rates of to penicillin, erythromycin, clindamycin, levofloxacin, and moxifloxacin were 83.7%, 34.6%, 31.7%, 3.9%, and 3.9%, respectively. None of the strains showed resistance to linezolid, daptomycin, tigecycline, vancomycin, or tetracycline. One hundred four strains of revealed that 49.0% (51/104) harbored enterotoxin genes, and most enterotoxin-positive strains carried only one gene type (90.2%, 46/51), while a minority carried two gene types (9.8%, 5/51). Besides, a total of 29 sequence types (STs) were identified with the three most prevalent STs: ST45, ST188, and ST6, accounting for 12.5%, 12.5%, and 9.6%.