TY - JOUR
T1 - Distributions of enterococci and human-specific bacteriophages of enterococci in a tropical watershed
AU - Chyerochana, Natcha
AU - Kongprajug, Akechai
AU - Somnark, Pornjira
AU - Leelapanang Kamphaengthong, Pinida
AU - Mongkolsuk, Skorn
AU - Sirikanchana, Kwanrawee
N1 - Funding Information:
We would like to acknowledge the funding sources: the Thailand Research Fund (contract no. SRI5930305 ) and the Chulabhorn Research Institute .
Publisher Copyright:
© 2020 Elsevier GmbH
PY - 2020/5
Y1 - 2020/5
N2 - The bacteriophages of E. faecalis strains AIM06 (DSM100702) and SR14 (DSM100701) have previously been validated as human-specific microbial source tracking (MST) markers in Thailand. In this study, their spatial and temporal distribution in a freshwater river was investigated for the first time (n = 48). The abundance of enterococci as a standard microbial water quality parameter was evaluated by both the qPCR detection assay with primers and a hydrolysis probe according to the US EPA Method 1611 and the US EPA Method 1600 membrane filtration culture method. AIM06 and SR14 phages were detected by a double layer agar assay and were present in 87.5% and 81.3% of all samples with a co-presence of 92.9% of phage-positive samples. After spiking the representative phages, the ranges of recovery efficiencies were 57.9–99.6% and 49.6–99.9% (n = 48) for AIM06 and SR14 phages, respectively. The absolute abundance of AIM06 and SR14 phages ranged from 0.25 to 221.94 and from 0.25 to 76.66 PFU/100 mL, respectively. Enterococci DNA copies and CFU were detected in all samples ranging from 3.24 to 6.32 log10 copies/100 mL and 100.00 to 1593 CFU/100 mL, respectively. Enterococci in the qPCR assay also showed a moderate correlation with the culture method. The AIM06 and SR14 phage results indicated continuing human faecal pollution along the river with no significant different levels among stations. Interestingly, the higher levels of enterococci in downstream stations for both the qPCR and culture methods along with the significant correlation with other faecal indicator organisms and non-human MST markers implied non-human faecal pollution. In conclusion, this study provides insightful information that could lead to effective water quality management and public health risk reduction from exposure to faecally-contaminated water.
AB - The bacteriophages of E. faecalis strains AIM06 (DSM100702) and SR14 (DSM100701) have previously been validated as human-specific microbial source tracking (MST) markers in Thailand. In this study, their spatial and temporal distribution in a freshwater river was investigated for the first time (n = 48). The abundance of enterococci as a standard microbial water quality parameter was evaluated by both the qPCR detection assay with primers and a hydrolysis probe according to the US EPA Method 1611 and the US EPA Method 1600 membrane filtration culture method. AIM06 and SR14 phages were detected by a double layer agar assay and were present in 87.5% and 81.3% of all samples with a co-presence of 92.9% of phage-positive samples. After spiking the representative phages, the ranges of recovery efficiencies were 57.9–99.6% and 49.6–99.9% (n = 48) for AIM06 and SR14 phages, respectively. The absolute abundance of AIM06 and SR14 phages ranged from 0.25 to 221.94 and from 0.25 to 76.66 PFU/100 mL, respectively. Enterococci DNA copies and CFU were detected in all samples ranging from 3.24 to 6.32 log10 copies/100 mL and 100.00 to 1593 CFU/100 mL, respectively. Enterococci in the qPCR assay also showed a moderate correlation with the culture method. The AIM06 and SR14 phage results indicated continuing human faecal pollution along the river with no significant different levels among stations. Interestingly, the higher levels of enterococci in downstream stations for both the qPCR and culture methods along with the significant correlation with other faecal indicator organisms and non-human MST markers implied non-human faecal pollution. In conclusion, this study provides insightful information that could lead to effective water quality management and public health risk reduction from exposure to faecally-contaminated water.
KW - Bacteriophages
KW - Enterococci
KW - Faecal indicators
KW - Microbial source tracking
KW - Water quality monitoring
UR - http://www.scopus.com/inward/record.url?scp=85079529276&partnerID=8YFLogxK
U2 - 10.1016/j.ijheh.2020.113482
DO - 10.1016/j.ijheh.2020.113482
M3 - Article
C2 - 32087504
AN - SCOPUS:85079529276
SN - 1438-4639
VL - 226
JO - INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH
JF - INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH
M1 - 113482
ER -
