Resistance, molecular epidemiology and virulence gene of non-A-F group serotype isolates of Salmonella enterica enteric subspecies isolated from children / 中华检验医学杂志

ABSTRACT

Objective:To analyze the anti-drug resistance, molecular epidemiology and virulence gene distribution of non-A-F group serotype isolates of Salmonella enterica enteric subspecis, so as to provide epidemiological basis for clinical diagnosis and treatment.Methods:Serotyping, antimicrobial susceptibility test and whole genome sequencing were performed on 11 isolates of non-A-F group serotype isolates of Salmonella enterica enteric subspecies that were isolated from The Children′s Hospital, Zhejiang University School of Medicine between 2017 and 2020. The serotype, multilocus sequence typing and virulence gene of the whole genome sequencing results were analyzed. Results:In our hospital, the detection rate of non-A-F group serotype isolates of Salmonella enterica enteric subspecies was low (1.13%). Among the 11 strains, there were 3 strains belong to Jangwani serotype, 2 strains of Hvittingfoss serotype, and Wandsworth, Pomona, Kedougou, Urbana, Poona and Kumasi serotypes have 1 strain each. Except for the two multi-drug resistant strains, the other strains were sensitive to most antibiotics, and the MICs were at low levels. A total of 9 ST types were detected in the 11 strains, the 3 Jangwani serotype strains were ST3918, and the other isolates were of different ST types. The phylogenetic tree shown that the three strains of Jangwani serotype were closely related. A total of 103 virulence genes were detected in the 11 strains, including 78 genes related to secretion system, 21 genes related to adherence, 2 genes related to magnesium uptake, 1 gene related to resistance to antimicrobial peptides and 1 gene related to typhoid toxin. Conclusions:The detection rate of the non-A-F group serotype isolates of Salmonella enterica enteric subspecies was low, and the sensitivity of the isolates to common antibiotics was high. The ST types and genetic relationship showed diversity. Clinical laboratory should pay attention to the detection of the non-A-F group serotype isolates of Salmonella enterica enteric subspecies, and the changes in drug resistance and virulence genes of the isolates should be closely monitored.