Infection dynamics of Salmonella Infantis strains displaying different genetic backgrounds – with or without pESI-like plasmid – vary considerably

Abstract

Food-borne infections with Salmonella are among the most common causes of human diseases worldwide, and infections with the serovar Infantis are becoming increasingly important. So far, diverse phenotypes and genotypes of S . Infantis have been reported. Therefore, the present study aimed to investigate the infection dynamics of two different S . Infantis strains in broilers. For this purpose, 15 birds were infected on day 2 of life with 10 8 CFU/ml of a pESI+ or a pESI– S . Infantis strain, respectively. Ten uninfected birds served as in-contact birds to monitor transmission. In both groups, an increase of infection was observed from 7 days of age onwards, reaching its peak at 28 days. However, the pESI+ strain proved significantly more virulent being re-isolated from most cloacal swabs and organs by direct plating. In contrast, the pESI– strain could be re-isolated from cloacal swabs and caeca only when enrichment was applied. Although the excretion of this strain was limited, the transmission level to in-contact birds was similar to the pESI+ strain. Differences in infection dynamics were also reflected in the antibody response: whereas the pESI+ strain provoked a significant increase in antibodies, antibody levels following infection with the pESI– strain remained in the range of negative control birds. The actual findings provide for the first time evidence of S . Infantis strain-specific infectivity in broilers and confirm previous observations in the field regarding differences in persistence on farms and resistance against disinfectants.

Antimicrobial and Antibiofilm Effect of Commonly Used Disinfectants on Salmonella Infantis Isolates

“…Recently, an S. Infantis strain-specific infectivity in broilers was also shown for the first time, and an increased potential of pESI-positive strains to colonize and infect birds was observed. As broilers infected with the pESI-positive strain were major shedders, a superior biofilm could also be attributed to environmental persistence of strains in broiler houses and consistent reinfection of birds [ 44 ]. The majority of strains ( n = 11) in our study harboured pESI-like plasmid, which is also a predominant S .…”

Antibacterial and antibiofilm activity of Melaleuca alternifolia (tea tree) essential oil against colistin resistant Salmonella enterica serotypes isolated from poultry environmental specimens

“…Infantis serovar is reported worldwide as one of the most common causes of foodborne human infections. It was included in studies that Infantis serotype was isolated from food and animal sources, usually from broilers and associated with human salmonellosis that not easily removed by disinfection from farms or environments such as slaughterhouses [51][52][53][54][55][56]. For this reason, it is important to search for an effective alternative method especially for Infantis serotypes that form biofilms.…”

Assessing Salmonella prevalence and complexity through processing using different culture methods

“…Kentucky is less clinically significant ( Shah et al, 2017 ). Studies have demonstrated that serovar Infantis can effectively colonize chickens, has increased tolerance to antimicrobials, and that some strains are multi drug resistant ( Asai et al, 2006 ; Shah et al, 2017 ; Pate et al, 2019 ; Drauch et al, 2020 ; Drauch et al, 2021 ; Zeng et al, 2021 ). Using CRISPR-SeroSeq, we determined that serovar Infantis was present at all sampling locations.…”