Molecular Analyses of Salmonella enterica Isolates from Fish Feed Factories and Fish Feed Ingredients

Abstract

Isolates of the most commonly observed salmonella serovars in Norwegian fish feed factories from 1998 to 2000 (Salmonella enterica serovar Agona, S. enterica serovar Montevideo, S. enterica serovar Senftenberg, and S. enterica serovar Kentucky) were studied by pulsed-field gel electrophoresis (PFGE) and plasmid profile analysis and compared to isolates of the same serovars from fish feed ingredients, humans, and other sources (a total of 112 isolates). Within each serovar, a variety of distinct PFGE types (with similarity levels less than 90%) were observed in the feed ingredients and other sources, while only two distinct types of each serovar were identified in the factories. The combined results of PFGE and plasmid analyses showed that each factory harbored only a few S. enterica clones. Some of these clones persisted for at least 3 years in the factories, indicating that there was long-lasting contamination probably due to inadequate decontamination procedures.

Biofilm forming ability of Salmonella enterica serovar Tennessee isolates originating from feed

“…the prominent feature of Salmonella organisms is their ability not only to contaminate but actively to colonize and invade plants, which has recently been confirmed using microscopy techniques for in situ visualization (LAPIDoT and YarON, 2009;krOuPItSkI et al, 2009;PATEL and Sharma, 2010). Salmonella are introduced into the feed factories via contaminated raw material (NeSSe et al, 2003). the organisms use similar survival strategies in both their natural habitat (plant surfaces) and the feed factory environment.…”

“…Such multicellular behavior (biofilm) enables salmonellas to persist in the feed factory environment for months, even years (NeSSe et al, 2003;VESTBy et al, 2009;møretrø et al, 2009). Salmonella biofilms from equipment and food contact surfaces are a well-established source of long-lasting contamination of final products, which has been repeatedly confirmed by molecular methods (NeSSe et al, 2003;PAPADoPouLou et al, 2009). In Great Britain, S. Tennessee is one of the top five most isolated serovars from feed for cattle, pigs and poultry (PAPADoPouLou et al, 2009). Very frequent instances of isolation of this serovar from feed and feed ingredients have also been reported in Denmark (ChrISteNSeN et al, 1997).…”

“…The biofilm organization pattern of salmonellas is most likely responsible for their increased resistance to a range of stress factors, such as long-term desiccation, low nutrients, and disinfectants from feed and the food factory environment AVILES et al, 2013). Such multicellular behavior (biofilm) enables salmonellas to persist in the feed factory environment for months, even years (NeSSe et al, 2003;VESTBy et al, 2009;møretrø et al, 2009). Salmonella biofilms from equipment and food contact surfaces are a well-established source of long-lasting contamination of final products, which has been repeatedly confirmed by molecular methods (NeSSe et al, 2003;PAPADoPouLou et al, 2009). In Great Britain, S. Tennessee is one of the top five most isolated serovars from feed for cattle, pigs and poultry (PAPADoPouLou et al, 2009).…”

Species distribution and antimicrobial susceptibility of enterococci isolated from broilers infected experimentally with Eimeria spp and fed with diets containing different supplements

“…there is the possibility the resident birds, small rodents or insects work as carries of resistant bacteria (35) and also iii) the poultry feed and feed ingredients could be the source of …”

Simultaneous Analysis of Multiple Enzymes Increases Accuracy of Pulsed-Field Gel Electrophoresis in Assigning Genetic Relationships among Homogeneous Salmonella Strains

“…It has become clear, however, that most S. enterica serovar Enteritidis isolates are derived from a few endemic clones and belong to a limited number of PTs (35,38). Pulsed-field gel electrophoresis (PFGE) remains a subtyping "gold standard" for public health investigation and has been shown to be highly effective for epidemiological investigation of Salmonella serovars (1,16,26). However, conventional PFGE has shown limited discriminatory power in subtyping certain highly clonal serotypes (e.g., S. enterica serovar Enteritidis and S. enterica serovar Hadar) (19,24,36).…”