SEMINAR 1 - MICROBIOLOGICAL ANALYSIS OF DRINKING WATER

SESSION 1: MICROBIOLOGICAL ANALYSIS OF DRINKING WATER: SAFEGUARDING PUBLIC HEALTH THROUGH LABORATORY SCIENCE

when it contains pathogenic and non-pathogenic organisms

according to WHO 1993, when is water unsafe for human consumption?

clear/colorless

free from objectionable taste and odor

must not conntain any substance or organisms, chemicals, and radioactive materials

criteria for drinking water

physical

chemical

bacteriological

radiological

water quality monitoring

bacteriological

as medtechs, what part of water quality monitoring do we test?

outbreak investigation of waterborne diseases

assesing safety, stability of water and water products for public consumption

determining level of sanitation during product preparation

regulatory compliance

reasons why we detect microorgtanisms in water

Salmonella

microbial pathogen for typhoid fever

Shigella

Microbacterial pathogen for shigellosis, bacterial dysentery

Escherichia coli

Microbacterial pathogen for Traveler’s diarrhea and Infantaile diarrhea

Vibrio cholerae

Microbacterial pathogen for Cholera

Campylobacter jejuni

Microbacterial pathogen for diarrhea

Poliovirus

Echovirus

Rotavirus

Norwalk virus

Microbacterial pathogen for gastroenteritis

Hepatitis A

Microbacterial pathogen for Hepatitisq

Giardia lamblia

Microbacterial pathogen for Giardiasis

Cryptosporidium parvum

Microbacterial pathogen for Cryptosporidiosis

Entamoeba histolytica

Microbacterial pathogen for Amoebiasis

coliform bacteria

no organism fulfills all the criteria for an indicatior organism but the

Facultative anaerobe

Aerobic

Gram Neg

Non-spore forming

Ferments lactose

Non-patho or Patho

What are coliforms?

E. coli

most numerous coliform

Direct Enumeration

Indirect enumeration

Pathogen isolation and identification

bacterial detection methods

Direct enumeration

microscopic count

cfu count using non-selective media

indirect enumeration

most probable number (MPN) or multiple tube fermentaiton technique

pathogen isolation and identification

uses a series of biological tests

multiple tube fermentation technique

standard membrane filtration technique

heterotrophic plate count (pour or spread plate)

enzyme substrate coliform test

delated incubation total coliform membrane filter technique

simultaneous detection of total coliform and E. coli by dual chromogen membrane filter

standard coliform detection methods

1. Multiple Tube Fermentation Technique

2. Standard Membrane Filtration Technique

3. Heterotrophic Plate Count (Pour or Spread Plate)

the only coliform detection methods used in testing in the laboratory (East Avenue Medical Center)

Heterotropic Bacteria

Broad group of pathogenic, non-pathogenic, and opportunistic organisms.

Heterotropic Bacteria

Its presence indicates the general biological condition of drinking water.

Agar to Sample

Sample to Agar

Difference of Spread and Pour plate

20 minutes (preferably 10 minutes)

Do not let more than________ elapse between starting pipetting and pouring plates.

44 & 46°C
3 hours

Maintain melted medium in a water bath at ______ until used, preferably no longer than _____

Counting (Glass Plate)

Grid-like similar to Neubauer counter

Vertically (6 squares downwards) and Horizontally (7 squares to the right)

How to read/count in Glass Plate

<1.0 CFU/mL

what to report if there are no colonies found

Glass plate: >6,500 est. CFU/ml

Plastic plate: >5,700 est. CFU/ml

what to report if there are greater than 100 colonies/cm²

<500 CFU/mL

Heteroptrophic Plate Count (HPC) Standard values

9215 B Pour Plate Method

9215 C Spread Plate Method

9215 D Membrane Filter Method

METHODS OF ANALYSIS for HPC

aerobic & facultative anaerobes, gram negative, non-spore forming, rod-shaped microorganisms which ferment lactose with gas formation within 48 hours @ 35°C.

MULTIPLE TUBE FERMENTATION TECHNIQUE PRINCIPLE

Most Probable Number (MPN) of organisms present.

in multiple tube fermentation techniques, the results of the examination of replicate tubes and dilutions are reported with?

five tubes of lauryl tryptose broth (LTB)

reagents used in presumptive testing

Formation of effervescence or gas displacement in the Durham tube

Gas Formation

what to look for in Presumptive testing after 24 hours? after 48 hours?

Brilliant Green Bile Lactose broth (BGLB) and E. coli (EC) broth

reagents used in confirmatory test

Membrane filtration technique

an effective, accepted technique for testing fluid samples for microbiological testing fluid samples for microbiological contamination.

Membrane filtration technique

Involves less preparation than many traditional methods and is one of the few methods that will allow the isolation and enumeration of microorganism

Magnetic funnel filter

Vacuum pump assembles

Membrane filter

Apparatus used in Membrane Filtration Technique

pink to dark red color with a metallic surface sheen.

typical coliform colony

dark red, mucoid, or nucleated without sheen.

Atypical coliform colonies

various shades of blue

Colonies produced by thermotolerant coliform bacteria

gray to cream colored.

Non thermotolerant coliform colonies