Coliforms ( other than E.coli) Fecal (thermo tolerant) E.coli Fecal streptococci Sulphite reducing clostridia Pseudomonas aeruginosa Bacteriophages specific for E.coli Container- Screw capped borosilicate glass or plastic bottles (500 ml) Avoid contamination Volume- At least 150-200 ml of water For testing dialysis water For testing clean water For testing large volume of water When bacterial count in water is expected to be low F o r t h e e s t i m a t i o n o f presumptive coliform count Extensively used for drinking water analysis For highly turbid samples F o r t h e e s t i m a t i o n o f presumptive coliform count Extensively used for drinking water analysis For highly turbid samples To confirm that the coliform bacilli detected in presumptive test are faecal E.coli Inoculate the positive tubes into brilliant green bile broth and tryptone water. Incubate at 44°C for 24 hours Positive for indole, acid, and gas production confirms thermotolerant E. coli Filtration of known volume of water sample on cellulose filter paper and incubate it on suitable culture media. Pore size = 0.2-0.45 μm Media : Membrane lauryl sulphate broth Drinking-water supply surveillance is “the continuous and vigilant public health assessment and review of the safety and acceptability of drinking-water supplies” (WHO, 1976). This surveillance contributes to the protection of public health by promoting improvement of the quality, quantity, accessibility, coverage, affordability and continuity of water supplies (known as service indicators) and is complementary to the quality control function of the drinking-water supplier. Drinking-water supply surveillance does not remove or replace the responsibility of the drinking-water supplier to ensure that a drinking-water supply is of acceptable quality and meets predetermined health-based targets All members of the population receive drinking-water by some means—including the use of piped supplies with or without treatment and with or without pumping (supplied via domestic connection or public standpipe), delivery by tanker truck or carriage by beasts of burden or collection from groundwater sources (springs or wells) or surface sources (lakes, rivers and streams). It is important for the surveillance agency to build up a picture of the frequency of use of the different types of supply, especially as a preliminary step in the planning of a surveillance programme. There is little to be gained from surveillance of piped water supplies alone if these are available to only a small proportion of the population or if they represent a minority of supplies. Information alone does not lead to improvement. Instead, the effective management and use of the information generated by surveillance make possible the rational improvement of water supplies—where “rational” implies that available resources are used for maximum public health benefit. Surveillance is an important element in the development of strategies for in

1. Water surveillance
Dr. Mayuri Bhise
Assistant professor,Department of
Microbiology, AIIMS Rajkot

2. Contamination with enteric
pathogens
Indicator organism
 Coliforms ( other than
E.coli)
 Fecal (thermo tolerant)
E.coli
 Fecal streptococci
 Sulphite reducing
clostridia
 Pseudomonas
aeruginosa
 Bacteriophages specific
for E.coli
Collection and transport
of water sample
• Container- Screw capped
borosilicate glass or
plastic bottles (500 ml)
• Avoid contamination
• Volume- At least 150-200
ml of water

3. Microbiological testing methods for
water analysis
Test
Multiple-tube method
Membrane filtration
method
• F o r t h e e s t i m a t i o n o f
presumptive coliform count
• Extensively used for drinking
water analysis
• For highly turbid samples
 For testing dialysis water
 For testing clean water
 For testing large volume of water
 When bacterial count in water is
expected to be low
•Presence /absence
method
•Medium containing
sodium azide

4. 50ml 10ml 1ml 0.1ml 0.01 0.001 0.000
ml ml 1ml
DS DS SS SS SS SS SS
Sample type
MacConkey purple broth (DS- double strength; SS-Single strength)
Unpolluted 1 5
water
Polluted - 5 5 5
water
Heavily - - 5 5 5 5 5
polluted
water
MULTIPLE TUBE METHOD
(Unpolluted)

5. McCrady statistical table
For Unpolluted
water
For polluted
water

6. Microbiological limits - drinking
water
Class Grading Coliform Count
/
100 mL (MPN)
E. coli count /
100 mL
Class-1 Excellent 0 0
Class-2 Satisfactory 1-3 0
Class-3 Suspicious 4-10 0
Class-4 Unsatisfactory >10 More than 0

7. Differential coliform count
(Eijkman test)
• To confirm that the coliform bacilli detected in
presumptive test are faecal E.coli
• Inoculate the positive tubes into brilliant green
bile broth and tryptone water. Incubate at 44°C
for 24 hours
• Positive for indole, acid, and gas production
confirms thermotolerant E. coli

8. Membrane filtration method
• Filtration of known volume
of water sample on
cellulose filter paper and
incubate it on suitable
culture media.
• Pore size = 0.2-0.45 μm
• Media : Membrane lauryl
sulphate broth
Count visually
identifiable colonies

9. × 100
× 100

10. THANK YOU