Evaluation of Salmonella Serotype Distributions from Commercial Broiler Hatcheries and Grower Houses

Abstract

By conventional trayliner (hatcheries) and drag swab assembly (broiler houses) culture methods, the isolation distribution of Salmonella serotypes from five commercial broiler hatcheries (three sample times) and 13 broiler farms (eight sample times) was evaluated. A total of 11 different Salmonella serotypes were isolated from hatcheries, with Salmonella heidelberg (9/30) and Salmonella kentucky (6/30) accounting for 50% of the total isolations. Of 700 chick paperpad trayliners sampled, regardless of lot (breeder flock source) or hatchery, 12% were positive for Salmonella. When 10 individual trayliners were cultured from individual lots (same breeder flock source), Salmonella was detected in 24/57 lots (42%). Multiple serotypes were simultaneously isolated from the same lot on three occasions (6%). Of the 21 lots that were serially sampled, the Salmonella serotype detected was different within lots eight times (38%) on at least one occasion of two or more sampling times. Of the 196 individual broiler houses sampled, 44 were positive for Salmonella (42%). Twelve different serotypes were isolated from broiler houses during this study. The serotypes isolated most frequently were S. heidelberg (34/94) and S. kentucky (22/94). These two serotypes accounted for 59.6% (56/94) of the total broiler house isolations. Of the 38 houses that were serially sampled, two or more serotypes were detected in the same broiler house on 20 occasions (53%). Of the 38 serially sampled houses (four or more times), a consistent Salmonella serotype was detected in five houses (13%). In only 5 of the 38 (13%) serially sampled houses did we fail to detect Salmonella on four or more samplings. No significant difference in Salmonella isolation frequency was observed between poultry houses using new or used litter. These data support previous findings indicating that paratyphoid Salmonella serotypes are prevalent in some broiler hatcheries and houses. Further, the observation of multiple serotypes simultaneously and serially isolated from the same breeder hatchery lots suggests that breeder flocks may be infected with more than one serotype, possibly providing a source for multiple serotype infections in progeny grower flocks.

Molecular and Phenotypic Analysis of the CS54 Island ofSalmonella entericaSerotype Typhimurium: Identification of Intestinal Colonization and Persistence Determinants

“…Analysis of fecal samples shows that between 1 and 6% of apparently healthy food animals in the United States shed S. enterica subsp. I serotypes with their feces (11,15,(17)(18)(19)44). Before slaughter, the prevalence of S. enterica subsp.…”

“…The causative agents, nontyphoidal serotypes of Salmonella enterica subsp. I, are introduced into the human food supply primarily because these pathogens persist within populations of livestock and domestic fowl (11,13,15,(17)(18)(19)44). Fecal contamination of the environment is the factor most important for the transmission of S. enterica subsp.…”

Mechanically Ventilated Broiler Sheds: a Possible Source of AerosolizedSalmonella,Campylobacter, andEscherichia coli

“…For Salmonella, the estimates of the incidence have been quite variable (16). As an example, there was a 42% prevalence for Salmonella in 198 U.S. broiler houses (9). As a general pattern, Salmonella can be isolated from a variety of sources (other than the bird) and at various stages of the production cycle (25).…”

Salmonella enterica serovar Enteritidis: a Mini-review of Contamination Routes and Limitations to Effective Control

“…Previous reports indicate that S. Enteritidis is the only human pathogen that contaminates eggs routinely even though the chicken farm environment is a rich source of other Salmonella serotypes 12,14,83 . Also, while penetration of cracked eggshells by bacteria was seen as a frequent cause of human illness before the introduction of grading schemes in the 1970s, but it is now known that egg contamination by S. Enteritidis may occur by vertical transmission in the reproductive tract before deposition of the shell 37,48,64 .…”