E. coli: The Good, The Bad, And The Ugly

Introduction How many of you like to go swimming in Lake Shafer? How many of you live in the “watershed area”?

What is a watershed? It is the area drained by a water system. Hoagland Ditch Watershed Honey Creek Watershed Point out that water runoff from land goes into the ditches and creeks in the watershed. All of these ditches and creeks drain into the main river, which includes Lake Shafer.

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E. coli & Lake Shafer Lake Shafer is known to contain high levels of E. coli periodically during the year. Sources of water and E. coli draining into Lake Shafer comes from the watershed area. 81% of these rivers, lakes, ponds, etc are too dirty for humans to swim in without the risk of getting sick. 81% of ditches, rivers, and lakes do not support full body contact recreation in Indiana (IDEM)

What is Escherichia Coli? E. coli was discovered by Dr. Theodor Escherich, who discovered this bacterium in 1885. It belongs to the Family Enterobacteriaceae. From Greek word enterikos (intestines) Have students try to pronounce the word Enterobacteriaceae. The size of one E. coli cell is 0.001 mm or 10 μm. The average diameter of a single piece of hair is 0.1mm, which is 100 times larger than a single E. coli cell. This means we all have bacteria in our intestines all of the time, including E. coli. These organisms happily inhabit the intestinal tract of most warm blooded animals. 0.001 mm 10 μm

E. coli Factoids E. coli colonizes the bowel of the average human fetus within 40 hours of birth. In newborn infants, most of the bacteria present are E. coli. There are approximately 107 (10,000,000) E. coli bacteria per 1 gram of an adult human’s intestine. Only 0.1% of the total bacteria in the adult human intestine are E. coli. Bring in a sugar cube or something that weighs only a gram. There are approximately 100,000 hairs on the average human head. Times that number by 100 and you have the number of E. coli in 1 gram of the human intestine.

Escherichia coli (E. coli) Can be used to indicate the possible presence of bacteria that may be harmful to human health. Other indicators of water quality test for things like sediment and fertilizers. E. coli is a good indicator of harmful bacteria in the water. Since we know E. coli lives in the intestines of animals, that after they go to the bathroom, their feces are full of bacteria, including E. coli. E. Coli is always in the intestines, so it is always in the feces. Therefore, if you have a large number of E. coli in the water, it could mean there is a lot of fecal matter in the water. When the water is cloudy and dirty looking it means all of the sediments (mud at the bottom of the waterbody) are being disturbed. Anything living or growing in the sediments is now going to be in the water too. Fertilizers are chemicals, and nobody likes to go swimming in certain types of chemicals. 0.001 mm BASIC RULE: If the water looks dirty, it probably is!!!

What Good Are E. coli? Protects the intestinal tract from bacterial infections Aids in digestion Produces our main source of vitamins B12 and K Symbiotic. E. coli doesn’t survive well if they are not inside our intestines. Human’s have a lot of intestinal problems, if E. coli is not present. 4) Lives symbiotically with us (we help them to live, and they help us to live)

Hmmmmm Who doesn’t want ANY bacteria or E. coli in them? It is really really good and important for you to have plenty of bacteria and E. coli in your intestines. Animals born and raised “germ free” are really wimpy . . . They have thin intestinal walls, puny heart output, and require lots of vitamin supplements just to stay alive.

Bad E. coli While most E. coli are good for you, there are a few strains of E. coli that are harmful to humans. ~ 5 billion bacteria in your intestines alone It is possible to get an individual strain of E. coli that is harmful to you. With such a large number of bacteria in your intestines, some of the bacteria combine and mutate into harmful strains of bacteria.

E. coli O157:H7 Most notorious strain of bad E. coli 0.001 mm Produces a powerful toxin and can cause severe illness Most dangerous for little kids, the elderly, and the sick Toxin is similar to poison Damages the intestines, causes bloody diarrhea, and other complications 0.001 mm

Local, National, & International Concern According to USDA, E. coli O157:H7 causes ~ 73,000 cases of infection and 61 deaths in the USA each year. Many countries around the world are constantly suffering from E. coli contamination. Most cases of infection are not severe and the individual just suffers diarrhea for a few days without further complications. Always hear don’t drink the water in Mexico. Poor water quality and always having diarrhea. Common cause of diarrhea in tourists

Case Study: New York 1999 Attendees of a county fair became ill from E. coli poisoning Source: Runoff from a barn that housed cattle contaminated the water supply at the fair At least 155 people became ill Start off with a barn and some cows. Then a storm comes in and rains. The rain water washes the cow’s manure into the streams or well water. The well water is now contaminated with E. coli. If some of the cows contain a harmful strain of E. coli anybody who drinks from the contaminated water will get sick as well.

Case Study: Georgia 1998 A toddler’s swimming pool was contaminated with E. coli Several children were hospitalized Toddler with diarrhea had an accident in the pool. Other children swimming in the pool swallowed some of the water and became sick. Chlorine from pools does kill bacteria, but it takes time

Main Sources of E. coli Undercooked meat Unpasteurized milk, apple juice, and orange juice Almost all milk, OJ, and AJ are pasteurized now, so this is no longer a large threat. Obviously most of you would probably not swim in water that looked like the bottom picture. Swimming in or drinking water contaminated with sewage

Most sources CAN be avoided!!! Main Sources of E. coli Bacteria in the diarrhea of infected persons can be passed on if their hands are not washed well Unwashed vegetables and fruits Most sources CAN be avoided!!!

What does this have to do with us? Lake Shafer contains high amounts of E. coli during different times of the year. Chances of getting sick from E. coli are very small But we want to make them even smaller! Research such as understanding where the E. coli is coming from. How the E. coli is getting into Lake Shafer, etc. Currently, research is being done to try and solve the problem.

E. coli in Lake Shafer E. coli concentrations up to 20,000 colony-forming units (cfu) per 100mL Indiana water-quality standard for full-body contact is 235 cfu/100mL Less money is made at Indiana Beach At times, Lake Shafer is way above the water quality standard for full-body contact. Many people see warnings or hear reports about Lake Shafer having poor water quality. They don’t want to come to Indiana Beach then, because they are afraid of getting sick. Indiana Beach loses money. Many people are blaming one another for the E. coli problem. Nobody wants to except responsibility and change their habits. It would be silly to spend tons of money trying to stop a possible source of E. coli from getting into the stream, and then finding out that it wasn’t a large source of E. coli. People blame one another for the problem More information needed to find cheap solutions that will work

The Scientific Method Theory: Hypothesis: Any idea, based on scientific fact, to explain something. Hypothesis: Ask students if they have any hypotheses. Lead them towards trying to figure out what possible sources are. An idea to account for certain facts, and it may be tested to see whether or not it is correct

Where’s It All Coming From? 1) Know what possible sources are: Farm Animals Fertilizers Sewage Treatment Plants Residential Areas (septic tanks) Farm Animals: Manure runoff Fertilizers: Manure fertilizers from agricultural fields Sewage Plants: Either a leak or not a good treatment plant Residential Areas: Old septic tanks that have broken, so their sewage is leaking into the water. 2) Some of these sources get into the water system

The Scientific Method Method: Results: Conclusion: A procedure or way of doing something Results: Interpretation of the data produced by the method used to test the hypothesis Conclusion: Summarizes briefly the hypothesis and the results to produce an ending to your experiment

Definitions Upstream: The direction from which the stream flows Downstream: The direction to which the stream flows Make sure to explain differences well Upstream Downstream Flow

Sampling Strategy (Methods) flow Method If think cows are source of E. coli, How would you test this idea? student ideas Want to take some water samples. COWS USED ONLY BECAUSE HAVE BEST GRAPHICS!! Where do you want to collect samples? Upstream, Downstream, at the site? Downstream and Upstream Why? If you sample downstream and get some numbers, that is great. How do you know that the cows are the sources of the E. coli or that something else further upstream is the source? That is why you need to have 2 samples for each source. One directly upstream of what you want to test, and one directly downstream of what you want to test. Then if there is a change in the number of E. coli, you know that what you were testing is a significant source. Have to take the upstream and downstream samples at about the same time to get most accurate results. If take on different days, and something happened between taking the samples, it could mess up your data. Must take multiple samples at different times to establish whether or not you get consistent results.

Cattle in the Ditch

Wastewater Treatment Plant

Residential Areas: Bays of Lake Shafer

Wastewater Treatment Plant

Collecting & Analyzing Data Place water sample on medium in petri dish. Wait 24 – 48 hours to allow E. coli to grow After you collect your samples, place a few ml of water onto the petri dish. Then cover the dish and allow the bacteria to grow for 24 – 48 hours. Medium is a nutrient broth (like soup broth) that contains foods E. coli like. So if a E. coli is in the water, then each E. coli cell will grow to form a colony. Other bacteria may be present on dish, however they are generally different colored colonies. E. coli tends to form blue/purple colonies. Each dot represents an entire colony of E. coli, not an individual E. coli cell Count colonies of E. coli in the petri dish

Results & Conclusions E. coli count units = cfu/100ml After having taken multiple samples, you need to analyze the data. In this data set, water samples were taken upstream of a possible source of E. coli. A sample was collected every 5 days. After filling in a table with days on the left and the number of E. coli found in the water from that days sample on the right. Doesn’t tell you much. Easier to see results by creating a graph. Place time on the x-axis. Time is independent variable (means it doesn’t matter what else is going on, it will be 5 days between samples) Place E. coli count on the y-axis for your dependent variable (depending on what day it is and what has happened that day, changes the amount of E. coli in the stream at the time the sample was taken). E. Coli is measured in colony forming units (cfu) per 100ml. Colony forming units are the visible dots seen on the petri dish plates. 100 ml refers to the size of the water sample. This is a standard used by scientists today. Can see that E. coli count varies from day to day This data and graph by itself does not tell you much. You need to have more.

Results & Conclusions E. coli count units = cfu/100ml This is data taken downstream of the source you are testing. Analyze data in same way as for the upstream sample. Once again have time on the x-axis and E. coli count on the y-axis. Can see there is a large increase in the amount of E. coli at this site. However, difficult to visualize results or tell how big of a difference there is between upstream and downstream of source. Need one more graph.

Results & Conclusions Putting all of the data together, you should see a graph like this. Can see the downstream source is obviously much greater than the upstream source. This trend is the same throughout entire graph w/ upstream having E. coli counts in the hundreds, and the downstream having E. coli counts in the thousands. Fairly safe to say this is a major source of E. coli Create graph by plotting both upstream and downstream results on same graph. Difference indicates the level of impact of E. coli from the source onto the rest of the stream. Notice that as you move downstream, the number of E. coli counts increases. This is because as you move downstream, new sources of water (and possible contamination) are being added into this large ditch that eventually empties out into the lake. Recall the watershed example where all the little streams were flowing into the large river. As you can see, not all of these E. coli plates are easy to count. Scientists get to use microscopes, but even then it may be difficult for them to accurately count all the E. coli colonies present. There is a large source of error possible here.