The capability of non-native strains of Bacteroides bacteria to detect bacteriophages as faecal indicators in a tropical area

• Main Authors: K. Sirikanchana, B. Wangkahad, S. Mongkolsuk
• Other Authors: Chulabhorn Research Institute
• Format: Article
• Published: 2018
• Subjects: Biochemistry, Genetics and Molecular Biology; Immunology and Microbiology
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/33488
• Institution: Mahidol University

© 2014 The Society for Applied Microbiology. Aims: To evaluate the use of nonlocal, already-available strains of phages to indicate faecal contamination in Thailand waters. Methods and Results: Phages of Bacteroides fragilis strains ATCC 700786 (RYC2056PH) and ATCC 51477 (HSP40PH) were measured in 71 human and animal wastewater samples in Thailand using a double-layer agar assay. Bacteriophage RYC2056PH was detected at concentrations comparable to representative human and animal wastewater samples from European and Mediterranean countries, with 61·7 and 33·3% above the threshold value of 100 PFU 100 ml^-1 in wastewater samples of human and animal origins, respectively. On the other hand, HSP40PH was detected at low concentrations in both human- and animal-polluted wastewaters. Moreover, RYC2056PH was found in 12 canal waters with human-influenced pollution and was not detected in 6 nonpolluted river waters being tested in this study. Conclusions: The presence of RYC2056PH could indicate nonsource-specific faecal contamination in Thailand. Significance and Impact of the Study: This study provided the first evidence that bacteriophages of the European-isolated B. fragilis strain RYC2056 could be used as nonsource-specific faecal indicators in the Southeast Asian region. The results of this study support the worldwide use of Bacteroides phages as faecal indicators.