Molecular epidemiology and virulence markers of Salmonella Infantis isolated over 25years in São Paulo State, Brazil

AbstractInfection of humans and animals caused by Salmonella is a major public health problem worldwide. Among the more than 2500 serovars, S. Infantis has been one of the 15 most isolated serovars in the world. Despite its clinical importance, little is known about the molecular characteristics of S. Infantis strains from Brazil. The aims of this study were to type S. Infantis isolates of this country and to assess their pathogenic potential. The molecular epidemiology of 35 S. Infantis strains, isolated from human sources (25) and food items (10) between 1984 and 2009 in São Paulo State, Brazil, were investigated using ERIC-PCR, PFGE and MLST. Furthermore, the presence of some virulence markers from Salmonella pathogenicity islands (SPIs) SPI-1 and SPI-2 and from the virulence plasmid was assessed by PCR. Using ERIC-PCR, 34 S. Infantis strains exhibited a high genetic similarity (⩾93.7%) and using PFGE, 32 strains exhibited a similarity ⩾80.6%. Additionally, MLST showed a high clonal similarity among strains that all presented the same ST32. Thirty-two isolates under investigation contained the virulence markers invA, sopB, sopD, sipA, sipD, ssaR, sifA, flgK, fljB and flgL. In conclusion, the S. Infantis strains studied were genetically similar, suggesting that a prevalent subtype has been causing disease and food contamination during a 25year period in São Paulo State, an important metropolitan region in Brazil. Furthermore, the contamination between strains from food items and sick humans indicates that better control measures for S. Infantis may be needed in this country

Plesiomonas shigelloides: Um enteropatógeno emergente?

Plesiomonas shigelloides is a Gram-negative rod-shaped bacterium, of the family Enterobacteriaceae, which has been isolated from freshwater and salt water, freshwater fish, shellfish and many species of animals. Most human P. shigelloides infections are suspected to be waterborne. The organism can be found in untreated water used as drinking water, in recreational water, or in water used to rinse food that is consumed without cooking or heating. The ingestion of P. shigelloides does not always cause illness in the host animal, and the organism may be present temporarily as a transient, noninfectious member of the intestinal flora. It has been isolated from the stools of patients with diarrhea,but it is also sometimes isolated from healthy individuals. P. shigelloides has been implicated in gastroenteritis, usually a self-limiting disease characterized by fever, chills, abdominal pain, nausea, diarrhea or vomiting; in severe cases the diarrhea may be yellowish-green, foamy and tinged with blood. The bacteria may also cause extra-intestinal infection. Furthermore, it can produce toxins and may be invasive. The evidence in favor of considering P. shigelloides as an enteropathogen is not totally convincing. Although it has been isolated from patients with diarrhea and incriminated in some outbreaks involving contaminated water and food, it was not possible, in many P. shigelloides samples associated with gastrointestinal infections, to identify a definite mechanism of virulence.Plesiomonas shigelloides é um bacilo Gram-negativo, pertencente à família Enterobacteriaceae, isolado de água doce e salgada, de peixes de água doce, mariscos e de inúmeros tipos de animais. Suspeita-se que a maioria das infecções humanas causadas por P. shigelloides, seja veiculada pela água, pois a bactéria está presente em águas não tratadas que são usadas para beber, águas recreacionais ou água para lavar alimentos que são consumidos sem cozimento ou aquecimento. A ingestão de P. shigelloides não causa sempre doença no animal hospedeiro, mas o microrganismo pode permanecer temporariamente como membro transitório não infeccioso da microbiota intestinal. A bactéria é isolada de fezes de pacientes com diarréia, mas algumas vezes também de fezes de indivíduos sem sintomas. A doença causada por P. shigelloides é a gastrenterite, que normalmente é auto-limitante, com febre, calafrio, dor abdominal, náusea, diarréia ou vômito. Em casos graves, as fezes diarréicas podem ser verde-amareladas, espumosas e com presença de sangue. A bactéria pode também causar infecções extra-intestinais. Ademais, pode produzir toxinas e ser invasora. As características utilizadas para considerar P. shigelloides como um enteropatógeno não são totalmente convincentes. Embora seja isolada de pacientes com diarréia e incriminada em vários surtos epidêmicos envolvendo água e alimentos contaminados, não foi possível identificar em muitas amostras de P. shigelloides, associadas com infecções gastrintestinais, um mecanismo de virulência definitivo. Palavras-chave: P. shigelloides; enteropatógeno; gastrenterite; diarréia; infecções extra-intestinais

Antimicrobial efflux pump encoding gene (ARG) profiles detected among the 80 <i>Salmonella</i> Infantis strains studied isolated from food (n = 27), farm and industry environments (n = 24), humans (n = 19), animals (n = 7) and animal feed (n = 3) in Brazil between 2013 and 2018.

Antimicrobial efflux pump encoding gene (ARG) profiles detected among the 80 Salmonella Infantis strains studied isolated from food (n = 27), farm and industry environments (n = 24), humans (n = 19), animals (n = 7) and animal feed (n = 3) in Brazil between 2013 and 2018.</p

Phylogenetic tree based on the core-genome multi-locus sequence typing (cgMLST) analysis of the 80 whole-genome sequenced <i>S</i>. Infantis strains studied, isolated from food (red squares; n = 27), farm and industry environments (green squares; n = 24), humans (blue squares; n = 19), animals (yellow squares; n = 7) and animal feed (orange squares; n = 3) between 2013 and 2018 in Brazil.

S. Infantis reference strain SINFA LN649235.1 (black square) was included for comparison purposes. Additional information regarding the isolation sources, efflux pump encoding genes (EPEG) and heavy metal tolerance genes are included. Profile 1 (acrA, acrB, baeR, crp, emrB, emrR, golS, hns, kdpE, kpnF, marA, marR, mdfA, mdtK, msbA, rsmA, sdiA, soxR, soxS); Profile 2 (acrA, acrB, baeR, crp, emrB, emrR, golS, hns, kdpE, kpnF, marA, marR, mdtK, msbA, rsmA, sdiA, soxR, soxS, tet(A)); Profile 3 (acrA, acrB, baeR, crp, emrB, emrR, golS, hns, kdpE, kpnF, marA, marR, mdtK, msbA, rsmA, sdiA, soxR, soxS); Profile 4 (acrA, acrB, baeR, crp, emrB, emrR, hns, kdpE, kpnF, marA, marR, mdfA, mdtK, msbA, rsmA, sdiA, soxR, soxS).</p

Antimicrobial resistance and plasmid profiles of the 80 <i>Salmonella</i> Infantis strains studied isolated from food (n = 27), the environment (n = 24), humans (n = 19), animals (n = 7) and animal ration (n = 3) between 2013 and 2018 in Brazil.

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List of the drug classes and resistance mechanisms as referred by the Comprehensive Antibiotic Resistance Database (CARD) of the efflux pump encoding genes detected among the 80 sequenced <i>Salmonella</i> Infantis strains studied isolated from food (n = 27), farm and industry environments (n = 24), humans (n = 19), animals (n = 7) and animal feed (n = 3) in Brazil between 2013 and 2018.

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Phylogenetic tree based on the core-genome multi-locus sequence typing (cgMLST) analysis of the 120 genomes of <i>S</i>. Infantis strains from Brazil, Canada, Ecuador Germany, Mexico, Peru, South Africa, United Kingdom (UK) and United States (US).

The 120 strains were isolated from food (red squares), environments (green squares), humans (blue squares), animals (yellow squares) and animal feed (orange squares). S. Infantis reference strain SINFA LN649235.1 (black square) was included for comparison purposes. Additional information regarding the isolation sources, core-genome sequence types (cgSTs) and the number and percentages of the identified alleles are included.</p

Strain identifiers and isolation data of the 80 <i>Salmonella</i> Infantis strains studied isolated from food (n = 27), farm and industry environments (n = 24), humans (n = 19), animals (n = 7) and animal feed (n = 3) between 2013 and 2018 in Brazil.

Strain identifiers and isolation data of the 80 Salmonella Infantis strains studied isolated from food (n = 27), farm and industry environments (n = 24), humans (n = 19), animals (n = 7) and animal feed (n = 3) between 2013 and 2018 in Brazil.</p