Clostridium botulinumin Cattle and Dairy Products

The two-component system CBO2306/CBO2307 is important for cold adaptation of Clostridium botulinum ATCC 3502

Clostridium botulinum is a notorious foodborne pathogen. Its ability to adapt to and grow at low temperatures is of interest for food safety. Two-component systems (TCSs) have been reported to be involved in cold-shock and growth at low temperatures. Here we show the importance of TCS CBO2306/CBO2307 in the cold-shock response of C. botulinum ATCC 3502. The relative expression levels of the cbo2306 and cbo2307 were up to 4.4-fold induced in the cold-shocked cultures but negatively regulated in the late-log and stationary growth phase in relation to early logarithmic growth phase in non-shocked cultures. Importance of the CBO2306/CBO2307 in the cold stress was further demonstrated by impaired growth of insertional cbo2306 or cbo2307 knockout mutants in relation to the wild-type strain ATCC 3502. The results suggest that the TCS CBO2306/CBO2307 is important for cold-shock response and adaptation of C. botulinum ATCC 3502 to low temperature.

Visceral botulism at dairy farms in Schleswig Holstein, Germany: prevalence of Clostridium botulinum in feces of cows, in animal feeds, in feces of the farmers, and in house dust

From 41 dairy farms in Schleswig Holstein, Germany, 196 fecal specimens of diseased cows, 77 fecal specimens of farmers and family members from 26 of these farms, 35 animal feed specimens and 7 house dust specimens were investigated for Clostridium botulinum and its antigens, respectively. Four of the humans under study (one child, 8 month, and three adults) showed symptoms of infant/visceral botulism. Specimens were cultivated in reinforced clostridial medium (RCM). C. botulinum antigens were detected by ELISA. The aim of the study was to obtain information on the relationship of detected C. botulinum toxin-types in cows, in the feces of attending humans, and in the immediate environment. The results revealed that C. botulinum toxin-types were different for cows and humans. Toxin-type A was dominant in cow feces while type E was found in humans. Type E was also present in some animal feed specimens. Conversely, toxin-type A was prevalent in the house dust of farms. It may be assumed that the feeds were the source of human colonization with C. botulinum.

Growth of group II Clostridium botulinum strains at extreme temperatures

The minimum and maximum growth temperatures and the maximum growth rates at 10, 30, 37, and 40°C were determined for 24 group II Clostridium botulinum strains. Genetic diversity of the strains was revealed by amplified fragment length polymorphism (AFLP) analysis. The minimum growth temperatures ranged from 6.2 to 8.6°C, and the maximum growth temperatures ranged from 34.7 to 39.9°C. The mean maximum growth temperatures and mean maximum growth rates of type E strains at 37°C were significantly higher than those of type B and type F strains. A significant correlation between maximum growth rates at 37°C and maximum growth temperatures was found for all strains. Some type E strains with a high minimum growth temperature also had a higher maximum growth rate at 37°C than at 30°C, which suggests that some group II C. botulinum strains are more mesophilic in their growth properties than others. We found relatively small differences between AFLP clusters, indicating that diverse genetic background among the strains was not reflected in the growth properties. The growth characteristics of group II C. botulinum and some type E strains with mesophilic growth properties may have an impact on inoculation studies and predictive modeling for assessing the safety of foods.