of viruses or pathogenic protozoa from fecal origin. In fact,
due to different physiological traits such as virus reproduction modes and the ability of protozoa to develop resistance
forms (cysts), viruses and protozoa are more resistant than FIB
to disinfection treatments that are used in drinking water and
wastewater treatment plants. As a consequence, other
indicators are being sought that could complement usual
FIB. Looking for some bacteriophages from specific fecal
bacteria such as coliphages is currently performed, but, up to
now, no indicator has been officially adopted. Enumeration of
Clostridium perfringens has also been proposed because this
fecal microorganism has the capacity to sporulate and, thus,
may be representative of the behavior of resistance forms of
some pathogenic protozoa. However, detection of these alternative indicators is more complex than the enumeration of
classical FIB. The characteristics of alternative indicators of
fecal contamination that are sometimes used in addition to
conventional indicators are summarized in Table 15.6.
Table 15.6 Characteristics of alternative fecal indicators in terms of prediction of fecal pollution and associated pathogens
Criteria for
fecal
indicators
Alternative fecal indicators
Bacteroides spp.
Bifidobacterium
spp.
Clostridium
perfringens
F-specific RNA
coliphage
B. fragilis phage
Fecal sterols
Presence in
the feces and
environmental
waters
Significant portion
of fecal bacteria
in warm-blooded
animals;
host-specific
distribution; wide
geographical
distribution of
human-specific
genetic markers
Significant portion
of fecal bacteria
in warm-blooded
animals;
host-specific
distribution; similar
frequency and
distribution of
species of
wastewater and
human fecal
isolates
Entirely of fecal
origin from
warm-blooded
animals; present
in wastewater
and sediment;
species distribution
varies among
animal species;
may indicate
remote or old fecal
pollution
Present in human
and animal feces as
well as in
wastewater; well
correlated with the
source of fecal
pollution
Mainly found in
human feces; could
be used as a specific
index of human
fecal pollution;
isolated from
sewage and fecally
contaminated water
Considerable
amount in animal
feces; indicator
of recent
contamination in
water and of old
or remote
contamination in
sediment; suitable
for temperate and
tropical regions
Ability to
multiply and
survive in the
water
environment
Short survival time
and inability to
replicate outside the
host; effect of
temperature and
predation on
survival rates; long
persistence of DNA
markers in water
Short survival time
outside the host;
unable to replicate
in oxygenated
nonhost
environment; low
frequency of
detection in warm
waters; inhibition
of the detection due
to background
bacteria
Extreme stability in
the environment
(more stable than
pathogens in
environmental
waters); no effect of
temperature and
predation on
survival
Possibility to
replicate in sewage;
sensitive to high
temperatures, solar
radiation in
conditions of high
salinity; similar
persistence with
enteric viruses
especially in
freshwater
No replication in
aquatic
environments; high
persistence in the
environment;
always more
abundant than
human enteric
viruses
Aerobic
degradation in
the water column;
incorporation in
sediments under
anoxic conditions
Correlation
with pathogens
or waterborne
disease
N.D.
N.D.
Good correlation
with some
pathogens; might
be an indication of
the effectiveness of
inactivation and
removal of viruses
and cysts; high
correlation with
diarrhea disease
levels
Valuable model for
viral contamination
and inactivation
Relate to the level
of human enteric
viral contamination
N.D.
Applied
methodology
Increasing use of
direct molecular
methods to identify
the origin of fecal
pollution using
host-specific
genetic markers
Use of direct
molecular methods
to identify the
origin of fecal
pollution using
host-specific
genetic markers
Indirect culturebased methods
Indirect (culture)
and direct
(molecular
biology) methods;
expensive and labor
intensive due to
their low
abundance in feces
and environment
Complex
methodology
requiring the
analysis of large
sample volumes;
indirect (culture)
and direct
(molecular biology)
methods
Simple and
sensitive analytical
method using gas
chromatographymass spectrometry
(GC-MS)
Modified from Savichtcheva and Okabe (2006)
640
P. Lebaron et al.
due to different physiological traits such as virus reproduction modes and the ability of protozoa to develop resistance
forms (cysts), viruses and protozoa are more resistant than FIB
to disinfection treatments that are used in drinking water and
wastewater treatment plants. As a consequence, other
indicators are being sought that could complement usual
FIB. Looking for some bacteriophages from specific fecal
bacteria such as coliphages is currently performed, but, up to
now, no indicator has been officially adopted. Enumeration of
Clostridium perfringens has also been proposed because this
fecal microorganism has the capacity to sporulate and, thus,
may be representative of the behavior of resistance forms of
some pathogenic protozoa. However, detection of these alternative indicators is more complex than the enumeration of
classical FIB. The characteristics of alternative indicators of
fecal contamination that are sometimes used in addition to
conventional indicators are summarized in Table 15.6.
Table 15.6 Characteristics of alternative fecal indicators in terms of prediction of fecal pollution and associated pathogens
Criteria for
fecal
indicators
Alternative fecal indicators
Bacteroides spp.
Bifidobacterium
spp.
Clostridium
perfringens
F-specific RNA
coliphage
B. fragilis phage
Fecal sterols
Presence in
the feces and
environmental
waters
Significant portion
of fecal bacteria
in warm-blooded
animals;
host-specific
distribution; wide
geographical
distribution of
human-specific
genetic markers
Significant portion
of fecal bacteria
in warm-blooded
animals;
host-specific
distribution; similar
frequency and
distribution of
species of
wastewater and
human fecal
isolates
Entirely of fecal
origin from
warm-blooded
animals; present
in wastewater
and sediment;
species distribution
varies among
animal species;
may indicate
remote or old fecal
pollution
Present in human
and animal feces as
well as in
wastewater; well
correlated with the
source of fecal
pollution
Mainly found in
human feces; could
be used as a specific
index of human
fecal pollution;
isolated from
sewage and fecally
contaminated water
Considerable
amount in animal
feces; indicator
of recent
contamination in
water and of old
or remote
contamination in
sediment; suitable
for temperate and
tropical regions
Ability to
multiply and
survive in the
water
environment
Short survival time
and inability to
replicate outside the
host; effect of
temperature and
predation on
survival rates; long
persistence of DNA
markers in water
Short survival time
outside the host;
unable to replicate
in oxygenated
nonhost
environment; low
frequency of
detection in warm
waters; inhibition
of the detection due
to background
bacteria
Extreme stability in
the environment
(more stable than
pathogens in
environmental
waters); no effect of
temperature and
predation on
survival
Possibility to
replicate in sewage;
sensitive to high
temperatures, solar
radiation in
conditions of high
salinity; similar
persistence with
enteric viruses
especially in
freshwater
No replication in
aquatic
environments; high
persistence in the
environment;
always more
abundant than
human enteric
viruses
Aerobic
degradation in
the water column;
incorporation in
sediments under
anoxic conditions
Correlation
with pathogens
or waterborne
disease
N.D.
N.D.
Good correlation
with some
pathogens; might
be an indication of
the effectiveness of
inactivation and
removal of viruses
and cysts; high
correlation with
diarrhea disease
levels
Valuable model for
viral contamination
and inactivation
Relate to the level
of human enteric
viral contamination
N.D.
Applied
methodology
Increasing use of
direct molecular
methods to identify
the origin of fecal
pollution using
host-specific
genetic markers
Use of direct
molecular methods
to identify the
origin of fecal
pollution using
host-specific
genetic markers
Indirect culturebased methods
Indirect (culture)
and direct
(molecular
biology) methods;
expensive and labor
intensive due to
their low
abundance in feces
and environment
Complex
methodology
requiring the
analysis of large
sample volumes;
indirect (culture)
and direct
(molecular biology)
methods
Simple and
sensitive analytical
method using gas
chromatographymass spectrometry
(GC-MS)
Modified from Savichtcheva and Okabe (2006)
640
P. Lebaron et al.