Comparison of fecal indicators with pathogenic bacteria and rotavirus in groundwater.
Groundwater is routinely analyzed for fecal indicators but direct comparisons of fecal indicators to the presence of bacterial and viral pathogens are rare. This study was conducted in rural Bangladesh where the human population density is high, sanitation is poor, and groundwater pumped from shallow tubewells is often contaminated with fecal bacteria. Five indicator microorganisms (E. coli, total coliform, F+RNA coliphage, Bacteroides and human-associated Bacteroides) and various environmental parameters were compared to the direct detection of waterborne pathogens by quantitative PCR in groundwater pumped from 50 tubewells. Rotavirus was detected in groundwater filtrate from the largest proportion of tubewells (40%), followed by Shigella (10%), Vibrio (10%), and pathogenic E. coli (8%). Spearman rank correlations and sensitivity-specificity calculations indicate that some, but not all, combinations of indicators and environmental parameters can predict the presence of pathogens. Culture-dependent fecal indicator bacteria measured on a single date did not predict total bacterial pathogens, but annually averaged monthly measurements of culturable E. coli did improve prediction for total bacterial pathogens. A qPCR-based E. coli assay was the best indicator for the bacterial pathogens. F+RNA coliphage were neither correlated nor sufficiently sensitive towards rotavirus, but were predictive of bacterial pathogens. Since groundwater cannot be excluded as a significant source of diarrheal disease in Bangladesh and neighboring countries with similar characteristics, the need to develop more effective methods for screening tubewells with respect to microbial contamination is necessary.
Department of Civil Engineering and Engineering Mechanics, Columbia University, NY, USA. asf747@gmail.com
Andrew S
AS
Ferguson
Alice C
AC
Layton
Brian J
BJ
Mailloux
Patricia J
PJ
Culligan
Daniel E
DE
Williams
Abby E
AE
Smartt
Gary S
GS
Sayler
John
J
Feighery
Larry D
LD
McKay
Peter S K
PS
Knappett
Ekaterina
E
Alexandrova
Talia
T
Arbit
Michael
M
Emch
Veronica
V
Escamilla
Kazi Matin
KM
Ahmed
Md Jahangir
MJ
Alam
P Kim
PK
Streatfield
Mohammad
M
Yunus
Alexander
A
van Geen
D001439:Bacteroides / Q000472:pathogenicity; D001459:Bangladesh; D003090:Coliphages / Q000472:pathogenicity; D060766:Drinking Water / Q000382:microbiology; D004755:Enterobacteriaceae / Q000472:pathogenicity; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity; D005243:Feces / Q000382:microbiology* / Q000821:virology; D060587:Groundwater / Q000382:microbiology* / Q000821:virology; D006801:Humans; D012401:Rotavirus / Q000472:pathogenicity*; D012760:Shigella / Q000472:pathogenicity; D014733:Vibrio / Q000472:pathogenicity; D014871:Water Microbiology
D060766:Drinking Water