Epidemiological Analysis of Salmonella Enterica Serovar Typhimurium and Serovar 1,4,,12:i:- Isolates Determined by Pulsed Field Gel Electrophoresis and Antibiotic Susceptibility: Comparison of Isolates from Broiler Chickens, Humans and the Environment in Reunion Island
Salmonella enterica ssp. enterica is a leading cause of bacterial food-borne disease outbreaks worldwide and is
also an economic burden particularly in Reunion Island because its population consumes large amounts of chicken and
cooks 100% chicken sausages (35 kg per capita per year).
The aim of this study was to investigate the epidemiology of Salmonella Typhimurium and Salmonella 1,4,,12:i:- from
broiler chickens, humans and the environment by using pulsed field gel electrophoresis (PFGE) and antibiotic
susceptibility and to assess the significance of broiler chicken meat as a source of human infection.
A total of 157 Salmonella Typhimurium and 19 S. I 4,,12:i:- were collected and isolated from broiler chickens, humans
and the environment between October 2007 and January 2009. The PFGE of Xba1 digested chromosomal DNA gave 30
distinct profiles for Salmonella Typhimurium and S. 1,4,,12:i:-. Salmonella Typhimurium was characterized by a main
pulsotype (B54) and accounted for 32% of all isolates. This pulsotype included isolates from many sources such as broiler
chickens, poultry houses, slaughterhouses, other animal species (ducks, pigs and rodents) and humans, suggesting that it
had already colonized every step of the food chain. Antibiotic susceptibility tests showed that most isolates were resistant
to ampicillin, streptomycin, sulfonamides and tetracycline.
The similarity of PFGE profiles of isolates from various sources and particularly from poultry and humans underlined
possible transmission of Salmonella from contaminated broiler meat, but most of the isolates remained drug-sensitive.
Significance and impact of study: Efforts are needed to eliminate Salmonella from poultry meat destined for human
consumption. This study has also shown the importance of monitoring antimicrobial resistance in bacteria associated with
animals and humans.