Molecular characterisation ofSalmonellastrains isolated from outbreaks and sporadic cases of diarrhoea occurred in Paraná State, South of Brazil

Abstract

A total of 46 strains of Salmonella isolated from patients with sporadic diarrhoea or involved in foodborne outbreaks were analysed by PCR for genus identification and serotyping. Subtyping was performed using pulsed-field gel electrophoresis (PFGE) and multiple amplification of phage locus typing (MAPLT) for seven variable loci. Bacteria were identified as belonging to serotype Enteritidis (33 strains; 71·7%) or Typhimurium (13 strains; 28·3%). A high similarity coefficient (94·6%) was observed in the Salmonella Enteritidis group for which were found three related PFGE profiles and only one MAPLT; strains representing profile PA/P1/MI were prevalent (27; 81·8%). Two Salmonella Typhimurium isolates were untypeable by PFGE. The remaining 11 strains had eight PFGE and three MAPLT profiles. The discriminatory power of MAPLT was lower than that of PFGE. Salmonella Enteritidis of clonal nature is predominant in Paraná State, with the most prevalent profile PA/P1/M1 associated with sporadic diarrhoea and with seven of nine reported outbreaks. In conclusion, PFGE shows higher discriminatory power among Salmonella strains.

Increasing prevalence and dissemination of invasive nontyphoidal Salmonella serotype Typhimurium with multidrug resistance in hospitalized patients from southern Brazil

“…This scenario is quite different from the main studies in Europe and North America where most isolates are from enteric origin. 30 , 31 Even the previous studies in South America have not demonstrated a so high frequency of non-enteric isolates. 28 On oppose, the rates of non-enteric and invasive salmonellosis are larger in Africa than in any other continent.…”

Salmonella enterica Prophage Sequence Profiles Reflect Genome Diversity and Can Be Used for High Discrimination Subtyping

“…To reduce the impact of outbreaks caused by foodborne pathogens, timely subtyping of isolates to incriminate sources of contamination is crucial. Conventional Salmonella typing methods such as PFGE, phage typing (PT), MLVA, and multiple amplification of phage locus typing (MAPLT) do not always provide the required level of discrimination (Assis et al, 2017 ; Ziebell et al, 2017 ). It was proposed previously that prophage composition could differentiate between S .…”

Phylogenetic analysis revealed that Salmonella Typhimurium ST313 isolated from humans and food in Brazil presented a high genomic similarity

“…In Brazil, Salmonella enterica has been reported as the main isolated pathogen in foodborne outbreaks and S. Typhimurium has been pointed as the first or second most isolated serovar in the country, depending on the location [6][7][8].…”