Multi‑locus sequence and drug resistance analysis of Salmonella infection in children with diarrhea in Guangdong to identify the dominant ST and cause of antibiotic‑resistance

Abstract

Multi-locus sequence typing (MLST) can be used to analyze the homology among the drug resistance gene cassettes in Salmonella and determine the prevalence. Information extracted using this technique can provide a theoretical basis for hospitals to devise protocols to control Salmonella infections. The aim of the present study was to investigate the possible association between drug resistance and integrons in clinical isolates of Salmonella from human fecal samples. Therefore, in the present study, 52 clinical fecal isolates of non-duplicate (i.e., not genome contamination) Salmonella were harvested from children with diarrhea and used for bacterial identification using biochemical tests, drug susceptibility analysis by antibiotic susceptibility testing and serotype identification using an agglutination assay. In total, seven Salmonella housekeeping genes (chorismate synthase, β sliding clamp of DNA polymerase III, uroporphyrinogen-III synthase, histidinol dehydrogenase, phosphoribosylaminoimidazole carboxylase catalytic subunit, 2-oxoglutarate dehydrogenase E1 component and homoserine dehydrogenase) were amplified and sequenced using MLST, before sequence alignment was performed against the Pub MLST database to determine the sequence-typed (ST) strains and construct genotypic evolutionary diagrams. Subsequently, the 52 Salmonella strains were subdivided into 11 serotypes and 11 sequence types. The dominant subtypes were found to be Salmonella typhimurium ST34 and ST19, which were diversely distributed. However, no new subtypes were found. Although the serotypes, including ST19, ST29, ST34, ST40, ST11, ST27, ST469, ST365, ST1499, ST413 and ST588, were closely associated with the MLST subtype, they did not correspond entirely. The detection rate of class I integrons was 38.46% (20/52), but no class II and III integrons were detected. The variable regions of three of 20 class I integrons were found to be amplified, whereas nine gene cassettes, including dihydrofolate reductase A12, open reading frame F, aminoglycoside-adenylyltransferase (aad)A2, aadA22, aadA23, aadA1, cadmium-translocating P-type ATPase 2, lincosamide and linF, were associated with drug resistance. These data suggest that Class I integrons are important factors underlying drug resistance in Salmonella, which may serve a role in the spread of drug resistance and warrant specific focus. In addition, MLST typing and serotyping should be applied cooperatively in epidemiological research.

Genomic characterization of Salmonella isolated from retail chicken and humans with diarrhea in Qingdao, China

“…I 4,[5],12:i:-). This is consistent with findings from previous reports in China ( Wang et al, 2020b ; Xu et al, 2022 ). Accordingly, among S. Enteritidis worldwide, ST11 is the predominant sequence type, accounting for 89% of the sequence types in the EnteroBase database ( Ashton et al, 2016 ).…”

“…The most common Salmonella sequence types were found to be ST11, ST34, and ST19 in this study, where the corresponding serotypes were S. Enteritidis and S. Typhimurium (including S. I 4,[5],12:i:-). This is consistent with findings from previous reports in China (Wang et al, 2020b;Xu et al, 2022). Accordingly, among S. Enteritidis worldwide, ST11 is the predominant sequence type, accounting for 89% of the sequence types in the EnteroBase database (Ashton et al, 2016).…”

“…The combination of MLST and serotype detection can facilitate research on the hereditary and evolutionary relationships of Salmonella ( Xu et al, 2022 ). The most common Salmonella sequence types were found to be ST11, ST34, and ST19 in this study, where the corresponding serotypes were S. Enteritidis and S. Typhimurium (including S .…”

Development and Evaluation of a Multiplex Fluorescence PCR for Salmonella Virulence Genes Analysis

“…The transmission routes of Salmonella to humans are diverse, including consumption of contaminated food or water and contact with infected animals and humans. According to estimates from the World Health Organization (WHO), more than 90 million cases of human salmonellosis occur globally each year (4). Therefore, the control and prevention of salmonellosis are crucial.…”

Epidemiological, Genetic, and Phenotypic Characteristics of Non-Typhoidal Salmonella in Young Children, as Obtained from a Tertiary Hospital in Guangzhou, China

“…Microorganisms 2023, 11, 2433 2 of 13 According to the White-Kauffmann-Le Minor scheme, over 2600 Salmonella serotypes have been identified worldwide, of which 292 different serotypes have been reported in China [13]. S. Enteritidis and S. Typhimurium are considered by the United States and European Food Safety Authority (EFSA) as the two most common serotypes causing human non-typhoidal salmonellosis [14,15].…”