Caracterización de cepas clínicas y ambientales de Salmonella enterica subsp. enterica serovar Heidelberg aisladas en Chile

Abstract

Characterization of Salmonella Heidelberg strains isolated in ChileBackground: Salmonella Heidelberg (S. Heidelberg) causes gastroenteritis and sometimes bacteremia and endocarditis. In other countries, this serovar has multidrug resistance including extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases (AmpC), associated with the bla CMY-2 gene. In Chile, an outbreak by S. Heidelberg occurred in 2011, the phenotypic and genetic characteristics of Chilean strains are unknown. Aim: To determine the antimicrobial susceptibility, presence of plasmids and virulence factor genes in S. Heidelberg strains isolated in Chile over the period and Methods: In sixty-one S. Heidelberg clinical and environmental strains collected by the Public Health Institute in Chile during 2006-2011, antimicrobial susceptibility, plasmids and virulence factor genes (invA, sifA, pefA, agfA, lpfA and, stkD) were studied. Results: S. Heidelberg had a high susceptibility to sulfamethoxazole-trimethoprim, gentamicin, ceftriaxone, ceftiofur, chloramphenicol, amoxicillin-clavulanic acid and ampicillin. However, 52% had decreased susceptibility to ciprofloxacin and 33% resistance to tetracycline. ESBLs were detected in three strains isolated from blood cultures, environment and human feces. The latter strain was positive for AmpC and bla CMY-2 gene. Fifty three of 61 strains showed one to seven plasmids of 0.8 to approximately 30 kb. Most plasmids were small with sizes between 0.8 and 2 kb. All isolates were positive for all genes except pefA. Conclusions: S. Heidelberg isolated from Chilean samples was susceptible to first-line antimicrobials, except tetracycline and ciprofloxacin. The emergence of strains with ESBLs and AmpC should be a warning. The strains were homogeneous for virulence genes, but heterogeneous in their plasmids.

Molecular Characterization and Survive Abilities of Salmonella Heidelberg Strains of Poultry Origin in Brazil

“…Our findings demonstrated higher phenotypic antimicrobial resistance against to AMO, AMP, COL, CFT, SMX, and TET commonly used in veterinary and human medicine routine when compared to results obtained in Brazil and Argentina (Borsoi et al, 2009;Aravena et al, 2019).…”

“…The ompC and invA genes are used to characterize the genus and the ability to invade host tissues, respectively, and the presence in all strains was expected. Together with the agfA and lpfA genes, they were previously identified in all Salmonella isolates in Brazil and Chile (Rowlands et al, 2014;Aravena et al, 2019). Both encode fimbriae-related proteins that carry essential adhesins that are associated with cell attachment to abiotic surfaces and biofilm formation for later intestinal colonization and expression of virulence, which indicates potential risk after infection (Yoo et al, 2013).…”

Detection of virulence genes in Salmonella Heidelberg isolated from chicken carcasses

“…Gene frequency variation and genetic profile may be influencing the survival and multiplication capacity of the strains over the years, subsequently leading to an increase in the frequency of this serotype isolated from poultry sources in Southern Brazil. Aravena et al 27 analyzed SH strains isolated in Chile between 2006 and 2011 and did not observe these variations. However, Antony et al .…”

“…It is worth mentioning that the sefA gene is considered one of the target genes for detecting and serotyping S. enteritidis 22 . The acquisition and loss of specific fimbrial operons may be one of the mechanisms by which different Salmonella serotypes have been able to adapt to an increasing number of hosts 27 . Studies have shown that fimbriae have tropism by different cell types in distinct hosts.…”

Emergence, Dissemination and Antimicrobial Resistance of the Main Poultry-Associated Salmonella Serovars in Brazil

“…However, it was also identified in other livestock and foods [170][171][172] (Figure 1). The outbreaks by this serovar have been reported worldwide [173][174][175][176][177][178][179][180].…”