Distribution of Enterotoxin Gene-positive Clostridium perfringens Spores among Human and Livestock Samples and its Potential as a Human Fecal Source Tracking Indicator

Abstract

In this study, to evaluate whether Clostridium perfringens could be a useful fecal indicator in aquatic environments and could be employed as a potential source-tracking indicator, the distribution of C. perfringens spores and their toxin types in sewage and livestock fecal samples were analyzed. A total of 804 C. perfringens spore isolates (366 from human-related sewage and effluents, 128 from cattle, 129 from pigs, 72 from chicken, and 109 from abattoir wastewaters) were analyzed using multiplex polymerase chain reaction (PCR) to detect six C. perfringens toxin genes. On the basis of the presence of toxin genes, most of the isolates from both human sewage and livestock samples were determined as C. perfringens type A and they expressed cpa alone or cpa and C. perfringens enterotoxin (cpe) with or without cpb2. Moreover, cpe-positive C. perfringens was detected with frequencies of 29% and 32% in human sewage and effluents, respectively. However, only one isolate (from cattle feces) was cpe-positive among all the livestock samples tested. Thus, the distribution of cpe-positive C. perfringens should be considered an important source tracking indicator for human fecal pollution. Furthermore, we conclude that sewage effluents are a significant source of cpe-positive C. perfringens pollution.