Re-Emergence of Salmonellosis in Hog Farms: Outbreak and Bacteriological Characterization

Abstract

Clinical salmonellosis has been increasing significantly in Brazil in recent years. A total of 130 outbreaks distributed among 10 swine-producing states were investigated. One representative Salmonella isolate from each outbreak was characterized through serotyping, antimicrobial resistance profiles, PFGE, and WGS. From 130 outbreaks: 50 were enteric, 48 were septicemic, 17 cases were characterized as hepato-biliary invasive, 13 as nodal and two were not classified. The most prevalent serovars were a monophasic variant of S. typhimurium (55/130), Choleraesuis (46/130), and Typhimurium (14/130). Most of the strains (86.92%) demonstrated a high rate of multi-drug resistance. The identification of a major Choleraesuis clonal group in several Brazilian states sharing the same resistance genes suggested that these strains were closely related. Six strains from this clonal group were sequenced, revealing the same ST-145 and 11 to 47 different SNPs. The detected plasmid type showed multiple marker genes as RepA_1_pKPC-CAV1321, the first to be reported in Salmonella. All AMR genes detected in the genomes were likely present on plasmids, and their phenotype was related to genotypic resistance genes. These findings reveal that salmonellosis is endemic in the most important pig-producing states in Brazil, emphasizing the need to make data available to aid in reducing its occurrence.

Global genomic epidemiology, resistome, virulome and plasmidome of the Extraintestinal Pathogenic Escherichia coli (ExPEC) ST38 lineage

“…S3). The pKPC-CAV1321 had been previously found in Citrobacter freundii and Klebsiella pneumoniae (Sheppard et al, 2016), and it was recently identified in Salmonella Choleraesuis spread in different Brazilian regions (Meneguzzi et al, 2021). However, so far, pKPC-CAV1321 has never been reported in any ExPEC lineage.…”

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

“…This can ensure the proper administration of efficient antibiotic therapy when necessary and establish an epidemiological correlation among strains isolated from different sources. Although S. 1,4, [5],12:i:-is one of the most prevalent serotypes in Brazil, few studies have described the antimicrobial resistance profiles and genotypic diversity of the strains of this pathogen in Brazil [24][25][26][27][28][29].…”

“…Although S . 1,4, [5],12:i:- is one of the most prevalent serotypes in Brazil, few studies have described the antimicrobial resistance profiles and genotypic diversity of the strains of this pathogen in Brazil [24–29].…”

Septicemic salmonellosis in suckling piglets resulting from improper intramuscular administration of an oral vaccine

“…7 S. enterica is most frequently associated with clinical disease in domestic animals, with > 2,600 serovars identified. 7,8 In pigs, 2 main serovars of S. enterica are linked to clinical disease: Salmonella Choleraesuis, typically causing septicemic clinical disease; Salmonella Typhimurium, generally causing enteric clinical disease. 7 Infection occurs mainly through fecal-oral transmission, and most Salmonella infections are subclinical.…”

“…8 Preweaning salmonellosis may be linked to environmental contamination, inadequate cleaning and disinfection of facilities, management mistakes, introduction of carrier animals, and poor infrastructure. 1,7,8 Furthermore, implementing effective measures to control and prevent salmonellosis can be challenging. These measures include biosecurity practices, adequate cleaning and disinfection, adopting all-in, all-out management, administration of antimicrobials in clinical cases, and the use of vaccines.…”