Genotypic and phenotypic characterization of <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Typhimurium monophasic variants isolated in Thailand and Japan

Abstract

Monophasic variants of Salmonella enterica serovar Typhimurium isolated in Thailand and Japan were characterized to elucidate the genetic basis of the monophasic phenotype, genetic relatedness, and antimicrobial resistance. A total of 20 Salmonella isolates agglutinated with anti-O4 and anti-H:i serum and not agglutinated with either anti-H:1 or anti-H:2 serum were identified as monophasic variants of Salmonella serovar Typhimurium because they harbored IS200, specific to this serovar, and lacked the fljB gene. An allele-specific PCR-based genotyping method that detects a clade-specific single nucleotide polymorphism indicated that seven swine isolates and one human isolate from Thailand were grouped into clade 1; five isolates from layer chicken houses and layer chicken feces from Japan were grouped into clade 8, together with two Salmonella serovar Typhimurium isolates from chicken houses in Japan; and five isolates from swine feces from Thailand and two isolates from layer chicken feces from Japan were grouped into clade 9. Multilocus sequencing typing demonstrated that sequence type (ST) 34 isolates were solely grouped into clade 9. Clade 1 and 8 isolates were assigned as ST19. Pulsed-field gel electrophoresis revealed multiple types within each of the clades. The presence of antimicrobial resistance genes and plasmid replicon type, of the clade 1 and 9 isolates were comparable to those reported for epidemic strains of monophasic variants. Our results suggest that monitoring monophasic variants of serovar Typhimurium is important for understanding of the spread of these variants in Thailand and Japan.

Evolution of Copper Homeostasis and Virulence in Salmonella

“…A similar phenotype was observed in Δ cueO cells grown aerobically ( Supplementary Figure 5 ) that are highly sensitive to Cu, with an exacerbated envelope stress under these conditions ( Pontel et al, 2010 ). This is in agreement with recent Salmonella isolates from Cu rich environments that harbor accessory Cu resistance determinants such as Cus-like efflux pumps as well as P-type ATPases and/or periplasmic copper binding proteins encoded in plasmids as well as in other mobile genetic platforms ( Mourão et al, 2016 ; Mastrorilli et al, 2018 ; Murase et al, 2018 ; Zhao et al, 2018 ; Arai et al, 2019 ; Branchu et al, 2019 ). Among them, an extrachromosomally encoded cus locus was present in clinic isolates ( Wiesner et al, 2016 ).…”

High levels of multidrug-resistant isolates of genetically similar Salmonella 1,4, [5],12:I:- from Brazil between 1983 and 2020

“…Molecular typing methods, such as pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR), have been successfully used to study the epidemiology and genotypic diversity of S. 1,4, [5],12:i:-strains in different countries [20][21][22]. Moreover, molecular typing is an important tool for determining the sources and vehicles of transmission and analysing whether the pathogen involved in an outbreak represents a single clone [23].…”

Caracterização molecular e fenotípica de linhagens de Salmonella 1,4, [5],12:i:- isoladas predominantemente no Estado de São Paulo entre 1983 e 2020

“…Diferentes métodos de tipagem molecular, como Pulsed-field gel electrophoresis (PFGE), Multilocus Sequence Typing (MLST) e Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) têm sido utilizados com sucesso para uma melhor caracterização epidemiológica e da diversidade genética de diferentes sorovariedades de Salmonella, incluindo S. 1,4, [5],12:i:-em diferentes países (BANERJI et al, 2020;MARIN et al, 2020;MURASE et al, 2018;POONCHAREON et al, 2019;SUN et al, 2020a).…”

“…Em relação a S. 1,4, [5],12:i:-, trabalhos demonstram que o PFGE tem sido aplicado com sucesso na tipagem de linhagens dessa variante monofásica (ANDREOLI et al, 2017;KIM et al, 2015;MANDILARA et al, 2021;MARIN et al, 2020;MURASE et al, 2018). -ŁUKOWSKA et al, 2021;MARIN et al, 2020;RAMTAHAL et al, 2022).…”