Typing of Clostridium perfringens from an epidemiological point of view

Clostridium (C.) perfringens type A is the causative agent of one of the most frequently occurring food intoxications in the western industrial nations. The available epidemiologic data reveal C. perfringens as one of the most commonly occurring bacterial agents of enteritis infectiosa, ranking behind Salmonella spp., Campylobacter spp. and Staphylococcus aureus. Therefore, it is of utmost importance to have suitable typing methods at one's disposition in order to be able to determine the infection sources and transmission routes of this pathogen. For the investigation of food-borne intoxications caused by C. perfringens conventional culture methods are still a well suited diagnostic tool. Taking into account the preliminary report (type of implicated food item or dish, catering method, duration of incubation and symptoms of the disease) and the laboratory criteria described by HAUSCHILD (e.g. C. perfringens counts in the suspected food item > 10(6)/g), a recently published colony-count technique according to DIN EN ISO 7937 (2004) including confirmation reactions is suitable for the determination of C. perfringens if the suspected food item is available for examination. In praxi, this will almost always be the case. In conclusion, the results of various studies are reported taking into consideration four molecular methods for the present evaluation. The suspect food item as well as feces samples of persons suffering from diarrhea were examined. In total, 35 C. perfringens strains, i.e. 12 food isolates and 23 strains isolated from patients who had consumed the implicated food item, were included in the investigations. The isolates originated from 10 different, well documented foodborne disease outbreaks which had occurred in Germany over a time period of eight years. The following methods were applied: 1) pulsed-field gel electrophoresis (PFGE) using Smal and Sa/l as macrorestriction enzymes (KLEIN, 1999), 2) plasmid profile analysis (EISGRUBER, 1997), 3) ribotyping (SCHALCH et al., 1997), and 4) analysis of the total soluble cytoplasmatic proteins by SDS-polyacrylamide gel electrophoresis (KLEIN, 1999). According to the results of the examinations performed, ribotyping and PFGE were best suited to confirm epidemiologic links of food intoxications due to C. perfringens.