Molecular Characterization of Salmonella enteritidis Isolates from Maine Poultry and Poultry Farm Environments

Abstract

Eighty-six Salmonella enteritidis isolates obtained during a surveillance program of poultry farms in Maine were subjected to phage-typing, plasmid profiling and fingerprinting, outer-membrane polypeptide analysis, and antimicrobial sensitivity testing. Isolates were obtained from a variety of sources, including poultry-farm environmental samples, chicken organ samples, human stool samples, cat feces, and live-trapped rats and mice. These isolates were compared with 21 S. enteritidis isolates originating outside of Maine. Phage types isolated in Maine included 13a (60%); 14b (29%); 23 (5%); 8 (2%); and 2 (2%). All S. enteritidis isolates from Maine carried plasmid DNA, and 97% of these isolates carried a 40.3-megadalton plasmid alone (6%) or in conjunction with several smaller plasmids (91%). All 52 phage-type 13a isolates harbored 40.3- and 3.0-megadalton plasmids. All 25 phage-type 14b isolates carried 3.3- and 1.3-megadalton plasmids, and 22 isolates also carried the 40.3-megadalton plasmid. All isolates displayed highly similar outer-membrane polypeptide profiles and were sensitive to a variety of antimicrobials commonly used against gram-negative organisms. The above data suggest that phage type and plasmid content may be related in the cases of phage-type 13a and 14b isolates, and that traditional plasmid-borne antimicrobial resistance determinants were not present in Maine isolates. Results also indicate that phage-typing can be a valuable epizootiological tool for monitoring the potential spread of these strains throughout the Northeast.

Diversity of Strains of Salmonella enterica Serotype Enteritidis from English Poultry Farms Assessed by Multiple Genetic Fingerprinting

“…In our study we found a similarity of plasmid sizes on specific farms and this could be due to preferential carrying of plasmids by specific PTs (predominant on those farms) or to transmission of these elements within bacteria on the farms. Several other studies have shown that multiple plasmid profiles can be seen among isolates of the same phage type and conversely that isolates assigned to different phage types can exhibit the same plasmid profile (30,40). This observations would suggest the possibility of plasmid transmission within isolates of different phage types.…”

Specific detection ofSalmonella entericaserotype Enteritidis using the polymerase chain reaction

“…A latex particle agglutiThorns and colleagues [26] did not react with all other serotypes; however, it agglutinated Dublin. Other methods based on gene restriction fragment patterns [27,28] and plasmid profile analyses [29] rely on DNA isolation and restriction digestion, which require several days to complete.…”

Animal Feed Production and Contamination by Foodborne Salmonella

“…A partial list of non-mammalian wildlife that have been demonstrated to carry Salmonella and could potentially come in contact with feed sources and food production animals include toads, vultures, lizards, tree frogs, and wild passerine birds (Everard et al, 1979;Kapperud et al, 1998). A partial list of documented infected and / or carrier mammalian species include rats, mice, Sika deer, mongooses, bats, monkeys, and opossums (Thigpen et al, 1975;Everard et al, 1979;Henzler and Opitz, 1992;Singer et al, 1992;Sato et al, 2000). Domestic cats and companion animal facilities have also been shown to be problematic for Salmonella (Singer et al, 1992;van Immerseel et al, 2004a;Wright et al, 2005).…”

“…A partial list of documented infected and / or carrier mammalian species include rats, mice, Sika deer, mongooses, bats, monkeys, and opossums (Thigpen et al, 1975;Everard et al, 1979;Henzler and Opitz, 1992;Singer et al, 1992;Sato et al, 2000). Domestic cats and companion animal facilities have also been shown to be problematic for Salmonella (Singer et al, 1992;van Immerseel et al, 2004a;Wright et al, 2005). Insects represent an additional potential carrier of Salmonella spp.…”