A combined case-control and molecular source attribution study of human Campylobacter infections in Germany, 2011\u20132014

Bettina M Rosner,Niklas Willrich,Friederike Kops,Klaus Stark,Janina Breidenbach,Kerstin Stingl,Christine Josenhans,Sebastian Suerbaum,Anika Schielke,Thomas Alter,Greta Gölz,Xavier Didelot

doi:10.1038/s41598-017-05227-x

Abstract

Campylobacter infection is the most commonly notified bacterial enteritis in Germany. We performed a large combined case-control and source attribution study (Nov 2011-Feb 2014) to identify risk factors for sporadic intestinal Campylobacter infections and to determine the relative importance of various animal sources for human infections in Germany. We conducted multivariable logistic regression analysis to identify risk factors. Source attribution analysis was performed using the asymmetric island model based on MLST data of human and animal/food isolates. As animal sources we considered chicken, pig, pet dog or cat, cattle, and poultry other than chicken. Consumption of chicken meat and eating out were the most important risk factors for Campylobacter infections. Additional risk factors were preparation of poultry meat in the household; preparation of uncooked food and raw meat at the same time; contact with poultry animals; and the use of gastric acid inhibitors. The mean probability of human C. jejuni isolates to originate from chickens was highest (74%), whereas pigs were a negligible source for C. jejuni infections. Human C. coli isolates were likely to originate from chickens (56%) or from pigs (32%). Efforts need to be intensified along the food chain to reduce Campylobacter load, especially on chicken meat.

Highlights

Intestinal Campylobacter infections are the most frequently reported bacterial infections in Germany and in other European countries[1, 2]
We received 2,073 questionnaires from case patients, corresponding to 22% of all cases notified to the local health authorities in the study region, and to 68% of patients that had received a questionnaire from the local health authority
Comparing participating campylobacteriosis cases to all non-participating cases that were notified to local health authorities in the study region, we found that they were similar in age, but a slightly higher proportion of participants was female (participants: median age 40 years; interquartile range (IQR) 24–54 years; 52% female; non-participants: median age 35 years; IQR 22–54 years; 47% female)

Summary

Introduction

Intestinal Campylobacter infections are the most frequently reported bacterial infections in Germany and in other European countries[1, 2]. Epidemiological studies conducted in several European and non-European countries have identified the consumption of poultry or chicken meat as an important risk factor for campylobacteriosis[14, 18,19,20,21,22,23], and in source attribution studies outside of Germany about 50–90% of human infections were attributed to chicken[7, 8, 10, 11, 13, 14, 24]. Our study was to identify risk factors for sporadic Campylobacter infections in Germany and combine epidemiological, molecular typing and source attribution data to determine the relative importance of potential sources for human infections

Results

Discussion

Conclusion