Presentation is loading. Please wait.

Presentation is loading. Please wait.

Microorganisms (The Coliform Group Bacteria) S. D. Spence.

Similar presentations


Presentation on theme: "Microorganisms (The Coliform Group Bacteria) S. D. Spence."— Presentation transcript:

1 Microorganisms (The Coliform Group Bacteria) S. D. Spence

2 Microorganisms w single-celled w generally microscopic w include bacteria, protozoa, algae, fungi, viruses w may or may not be disease causing

3 Implications of Microbial Contamination of Water w potential for transmission of disease causing microorganisms (pathogens) via water contact - oral fecal route w contact includes ingestion, primary contact, and secondary contact

4 Water Borne Diseases/Pathogens w Bacteria Vibrio cholera - cholera Yersinia enterocolitica - gastroenteritis Escherichia coli - gastroenteritis Shigella sp.- gastroenteritis Listeria monocytogenes - flu-like symptoms Salmonella sp. - gastroenteritis, typhoid Campylobacter jejuni - gastroenteritis (animals sources)

5 Vibrio cholerae

6 Yersinia enterocolitica

7 E. coli

8 Shigella

9 Clostridium perfringens

10 Water Borne Diseases/Pathogens w Viruses Polio Virus - paralytic poliomyelitis Rotaviruses - gastroenteritis Norwalk Viruses - gastroenteritis Hepatitis Type A and E - liver inflammation

11 Polio Virus

12 Rotavirus

13 Norwalk Agent

14 Water Borne Diseases/Pathogens w Protozoa Entamoeba histolytica - amoebic dysentery Giardia lamblia - intestinal disease Cryptosporidium - intestinal disease

15 Giardia lamblia

16 Difficulties With Routine Testing Of Pathogens in Water w present in low numbers w limited survival time w numerous pathogens to analyze w time and cost prohibitive

17 Testing of Indicator Organisms w need an indicator of potential pathogen contamination of water which is easy, reliable, inexpensive, quick, etc.

18 Requirements of Indicator Organisms w present when pathogens present in water w absent in uncontaminated water w present in higher numbers than pathogens in contaminated water w better survival in water than pathogens w easy to analyze

19 Coliform Bacteria - Indicators of Fecal Contamination w bacteria in the family Enterobacteriaceae w generally include the genera Enterobacter, Klebsiella, Citrobacter, and Escherichia w present in the intestinal tract of numerous organisms w gram negative, non-spore forming rods w ferment lactose with acid and gas production in 48 hours at 35 °C

20 Total Coliform Bacteria w inhabit the intestinal tract of animals w sources: fecal material, soil, water, grain w some capable of reproduction in the environment w non-fecal examples include: Klebsiella sp., Citrobacter sp., Enterobacter sp.

21 Fecal Coliform Bacteria w subset of the total coliform group w separated from non-fecal coliforms by growth at 44.5 °C w sources: fecal material w capable of limited survival and growth in the environment w primary example is Escherichia coli (E. coli)

22 Can Stagnant Water Result in Positive Coliform Results? w presence of coliform bacteria indicates influence from a source - human activity, fecal material, soil, water, grain w stagnation of water - environment for reproduction of bacteria allowing great enough numbers to be detected

23 Coliform Sample Preservation

24 w sodium thiosulfate added to chlorinated samples w no additives for nonchlorinated samples w recommended-drinking water samples iced w required-source water samples iced

25 Coliform Sample Holding Times and Analyses Methods

26 Source Water vs. Drinking Water w Drinking water and source water have different requirements for coliform analysis methods and holding times

27 Coliform Sample Holding Times w drinking water - 30 hours [40 CFR 141.21(f)] w surface/source water - 8 hours [40 CFR 141.74 (a)(1)]

28 Effects of Holding Time on Samples w coliform numbers may decline w coliform numbers may increase w hetertrophic (non-coliform) bacteria may increase and inhibit detection of coliforms in the sample

29 Heterotrophic Interference w Non-coliform bacteria which are better than coliforms at surviving in the environment may be present in the sample. If these organisms are given a chance to grow, they may out-compete coliforms during analysis and may limit the analysts ability to detect coliforms. The effect of HI is an underestimation of coliform numbers or a false negative result.

30 Holding Times Are Critical w greater chance of heterotrophic interference in untreated source water - hence, shorter allowable holding time

31 Coliform Methods

32 Choosing a Laboratory for Testing w laboratory must be certified by the State or EPA to conduct analyses of compliance drinking water and surface/source water samples [40 CFR 141.28(a), 40 CFR 141.74(a)]

33 Certified Laboratory w granted certification by State or EPA w meets QA/QC requirements w analyzes blind audit samples w audited every 3 years w documentation of certification w certified for specific methods

34 Approved Drinking Water Methods

35 Approved Source Water Methods

36 Approved Drinking Water Methods [40 CFR 141.21 (f)] w Membrane Filter Method - total coliforms, fecal coliforms, E. coli w Multiple Tube Fermentation Method- total coliforms, fecal coliforms, E. coli

37 Approved Drinking Water Methods [40 CFR 141.21 (f)] w Presence/Absence Method - total coliforms, fecal coliforms, E. coli w Colilert Method - total coliforms, E. coli w Colisure Method - total coliforms, E. coli

38 Membrane Filter Method 4 to 5 day test w metallic green colonies on endo medium- presumptive coliform positive w growth/gas in LTB and BGBB - confirmed total coliform positive w growth/gas in LTB and EC medium - confirmed fecal coliform positive w growth and gas in LTB and growth and fluorescence in EC + MUG - confirmed E. coli positive

39 Membrane Filter Method (Endo agar with coliform growth)

40 Multiple Tube Method 5 day test w growth/gas in LTB- presumptive coliform positive w growth/gas in BGBB - confirmed total coliform positive w growth/gas in EC medium - confirmed fecal coliform positive w growth and fluorescence in EC + MUG - confirmed E. coli positive

41 Multiple Tube Fermentation Method (Total Coliforms)

42 Fecal Coliform/E. coli Multiple Tube Method - EC medium + MUG

43 Presence Absence Method 5 day test w growth/acid in PA broth - presumptive coliform positive w growth/gas in BGBB - confirmed total coliform positive w growth/gas in EC medium - confirmed fecal coliform positive w growth and fluorescence in EC + MUG - confirmed E. coli positive

44 Colilert and Colisure Methods 1 day test w color change in culture media - confirmed total coliform positive w production of fluorescence under 366 nm UV light - confirmed E. coli positive

45 Colilert Method

46 Useful References w Standard Methods for the Examination of Water and Wastewater, 18th Edition, 1992, American Public Health Association, 1015 Fifteenth Street NW, Washington, D.C., 20005 w Total Coliform Rule (40 CFR 141.21) w Surface Water Treatment Rule (40 CFR 141.74)

47 Photo References w Microorganism photos scanned from Microbiology Concepts and Applications, Pelczar et al., McGraw-Hill, Inc., 1993 w Media vials and plate photos scanned from Products and Analysis 1999, Hach Company, P.O. Box 608, Loveland Colorado, 80539-0608


Download ppt "Microorganisms (The Coliform Group Bacteria) S. D. Spence."

Similar presentations


Ads by Google