Microbes. Image Source: dhmh.maryland.gov

Transcription

1 Microbes AND CULTURING TECHNIQUES Image Source: dhmh.maryland.gov

2 Microbes Image Sources: nuigalway.ie; clordisys.com

3 Microbes Have been around for at least 3.5 billion years Rise of the Cyanobacteria Most abundant life form on Earth Affect every aspect of life on earth Variety of shapes and sizes Can exist in a wide range of habitats Image Source: nuigalway.ie

4 Microbes Include: All bacteria All archaea Almost all protozoa Some fungi Some algae Certain animals and plants Juvenile stages of macro-animals and macro-plants And (depending on who you ask) viruses Microbe Examples Image Source: Mined from Google image search

5 Microbiology The study of microorganisms ( microbes ) is called Microbiology Discovery in 1674 Antonie van Leeuwenhoek Robert Hooke Image Sources: micro.magnet.fsu.edu; lacienciaexplica.blogspot.com

6 Importance of Microbes I make no apologies for putting microorganisms on a pedestal above all other living things. For if the last blue whale choked to death on the last panda, it would be disastrous but not the end of the world. But if we accidentally poisoned the last two species of ammoniaoxidisers, that would be another matter. It could be happening now and we wouldn t even know... - Tom Curtis July 2006 in Nature Reviews Microbiology

7 Microbes & Human Health Microbes outnumber somatic cells in the human body Human digestive system Skin and internal organs A relatively small number of microbes are harmful to human health Pathogenic Examples: Ebola virus, Malaria, HIV, Strep throat, Staph infection, influenza, common cold, measles, chickenpox, tuberculosis, food poisoning, anthrax, etc. Image Source: nuigalway.ie; louisville.edu Mycobacterium tuberculosis

8 A pathogen is a microorganism that has the potential to cause disease. An infection is the invasion and multiplication of pathogenic microbes in an individual or population. Disease is when the infection causes damage to the individual s vital functions or systems. To make us ill microbes have to: Reach & attach to their target site in the body Multiply rapidly Obtain nutrients from the host Survive attack by the host s immune system Source: microbiologyonline.org.uk

9 Microbes & Ecosystems Microbes are important decomposers Bacteria, fungi, and algae all participate in breaking down waste material Decomposition is important because: Releases nutrients Cycles important compounds in and between ecosystems Some microbes employ photosynthesis Use radiant energy (sunlight) to convert CO 2 into O 2 Image Source: nuigalway.ie

10 Microbes & Food Food spoilers Food poisoning Penicillium mold growing on bread Image Source: microbiologyonline.org.uk The bacterium Campylobacter jejuni is a common cause of food poisoning

11 Microbes & Food Eight major pathogens responsible for most foodborne illnesses in U.S.: Image Source: microbiologyonline.org.uk

12 Microbes & Food Microbes are used in the production of many foods: Yogurt Cheese Bread Beans Chocolate Wine Beer Image Source: Mined from several Google image searches

13 Microbes & Medicine Vaccines Antibiotics Probiotics (and prebiotics) Development & production of medical drugs Image Source: Mined from Google image search

14 Microbes & Industrial Applications Wastewater treatment plants Composting facilities & landfills Methane gas as an energy source Biofuel GMOs Image Source: 2013.igem.org

15 Microbes & Natural Waters Clean Water Act of 1972 (CWA) Protection of surface water for drinking water, recreational, and aquatic food source uses Safe Drinking Water Act of 1974 (SDWA) Regulation of contamination of finished drinking water and protection of source waters US EPA Water Quality Standards Recreational waters Drinking water

16 US EPA Drinking Water Standards Contaminant Cryptosporidium Giardia lamblia MCLG (mg/l) zero zero Potential Health Effects from Long-Term Exposure Above the MCL Gastrointestinal illness (such as diarrhea, vomiting, and cramps) Gastrointestinal illness (such as diarrhea, vomiting, and cramps) Legionella zero Legionnaire's Disease, a type of pneumonia Total Coliforms (including fecal coliform and E. Coli) Turbidity Viruses (enteric) zero n/a zero Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present Higher turbidity levels are often associated with higher levels of disease-causing microorganisms. These organisms can cause symptoms such as nausea, cramps, diarrhea, and associated headaches. Gastrointestinal illness (such as diarrhea, vomiting, and cramps) Sources of Contaminant in Drinking Water Human and animal fecal waste Human and animal fecal waste Found naturally in water; multiplies in heating systems Coliforms are naturally present in the environment; as well as feces; fecal coliforms and E. coli only come from human and animal fecal waste. Soil runoff Human and animal fecal waste

17 US EPA Recreational Water Standards Class Freshwater Marine Shellfishing 14 FC 14 FC Recreational (swimming) Based on median value. No more than 10% of FC samples may exceed 43 in the areas most probably exposed to fecal contamination. 200 FC 200 FC No more than 20% of FC samples may exceed 400. Violations are expected immediately following periods of rainfall in areas where uncontrollable nonpoint source pollution prevents attainment. North Carolina

18 Culturing Microbes LABORATORY TECHNIQUES Image Source: kemira.com

19 Culture Media Contains nutrients needed to sustain microbe growth and reproduction Can be liquid (broth) or gelatinous (gelatin or agar) Media can vary widely in ingredients Common ingredients include: Glucose or glycerol carbon sources Ammonium salts or nitrates inorganic nitrogen sources Animal extracts (broth) additional nutrient sources Animal proteins or plant carbohydrates solidifiers

20 Selective & Differential Media Selective Media: Assists the growth of a desired organism Stops the growth of (or kills) non-desired organisms Differential Media: Creates a visible change when growth of target organisms are present (e.g., color change)

21 MacConkey Agar Most common Selective and differential Isolates enteric, gram-negative bacteria based on their ability to ferment lactose.

22 Gram-positive vs. Gram-negative Gram-positive bacteria: retain crystal violet dye thick layer of peptidoglycan Lack outer membrane Gram-negative bacteria: do not retain the violet dye Possess outer membrane (cell wall) more resistant against antibodies because of their impenetrable cell wall Image Source: vetsci.co.uk

23 Aseptic Technique Mindset and procedures that maintain a contamination-free lab space: Good hand washing technique Mindfulness of sources of contaminants Gathering all materials & staying at the lab bench until all culture work is complete Avoid coughing, sneezing, or breathing on samples Keeping sample covered at all times Maintaining a sterile environment around the immediate work area

24 Microbe Control Methods Sanitize: Make safe to use or eat from Disinfect: Kill pathogens present Sterilize: Kill or remove all life present

25 Ways to Sterilize & Disinfect STERILIZE Burning Boiling Autoclave (steam) Filtration Irradiation Ozone Nitrogen dioxide Formaldehyde Hydrogen Peroxide Alcohols Chlorine Iodine DISINFECT Detergents/Soaps Acids & Alkalis Alcohols Chlorine Aldehydes Iodophors Heavy metals (i.e. mercury and silver) Cresols/Phenols Hydrogen peroxide Antibiotics Heating Pasteurization

26 Flame Sterilization Image Source: shuledirect.co.tz