Food Standards Agency
Saturday 20 March 2010
Business campaign
AZ-Directory
What's NewRSS
What is RSS?Listen
Listen to this siteThursday 16 February 2006
This research project will use the typing method MLST to compare Scottish campylobacter isolates from human infections with those from food and environmental sources.
Study Duration : June 2005 to January 2009
Contractor : University of Aberdeen
Despite the worldwide importance of Campylobacter as an enteric pathogen much remains to be understood about its epidemiology and associated risk factors. A greater understanding of this area is vital for the development of effective control programmes to reduce human Campylobacter infection.
The Advisory Committee on the Microbiological Safety of Food (ACMSF) 2nd Report on Campylobacter recommended that the Agency considered multilocus sequence typing (MLST) in its future investigative programmes to improve future epidemiological study of Campylobacter over the next few years.
Through the use of MLST, this project aimed to examine the population genetics of Campylobacter isolated from clinical, food and environmental samples and to investigate epidemiological links and sources of Campylobacter infection in the Scottish population.
Clinical Campylobacter isolates obtained from Scottish NHS diagnostic laboratories over a 15-month period were typed using MLST. These were compared with the MLST profiles from more than 1000 food and environmental isolates collected over the same period throughout Scotland. This represents the world’s largest national-scale, contemporaneous comparison to date of Campylobacter strain types from clinical cases and a broad range of environmental and food sources of infection. The resulting MLST profiles were analysed and compared with other published profiles in order to identify epidemiological links and sources of infection.
A highly diverse range of strain types (MLST profiles) were observed across all of the clinical, food and environmental isolates analysed in the study. Comparisons of the MLST profiles of clinical Campylobacter isolates with those of food and environmental isolates identified retail chicken as the single largest source of Campylobacter infection in Scotland. This is consistent with published findings on the prevalence of Campylobacter in broiler chickens and the significance of chicken consumption as a risk factor in clinical Campylobacter infection. A further important finding from this project was that MLST profiles of Campylobacter isolated from cattle and sheep faeces sampled during the study matched those isolated from human infections. This suggests that farm ruminants could also be a significant risk factor for Campylobacter infection in Scotland, although further research is required to determine the relative importance of the routes for human infection via these sources.
Further analyses were conducted on clinical MLST profiles in order to assess the levels of strain diversity and spatio-temporal clustering of human Campylobacter cases during the 15 month period of the study. The diversity of strain types was spread across Scotland and there was no indication of particular strains being more common in some regions than in others. Isolates from cases that were already known to be linked (outbreaks) included common strain types, but more generally only a small proportion of isolates were clustered, with the majority of clinical cases that occurred during the period of the study apparently being sporadic.
This research has served to underline the likely importance of intervention strategies targeted to the broiler food chain in reducing the rates of infection in the Scottish population. It also highlights the need for further work to elucidate the significance of farm ruminants as a direct or indirect source of human infection.
A full version can be found on (External) Foodbase .
Find out what our other sites have to offer