Fecal Indicator Bacteria and Sanitary Water Quality

[Guest guest]

I was looking for information on a show I saw the other night. It was

about a deadly and resistant bug ( I cannot remember the name they

called it) that flooded hospitals with thousands of people and had

several deaths. The story itself freaked me out but the end result

was that human sewage being dumped into Lake Michigan was going right

into the drinking water supply and nothing they did killed it.

Anyway I cant find the information ironicly. But I found this lovley

information.

A Little Information About Microorganisms

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Microorganisms are found everywhere in our environment. They are

common in the air, soil, water and in the habitats of our daily

lives. The vast majority of microorganisms do not cause disease.

Instead, they maintain the fertility of soil, they degrade wastes in

our landfills and compost piles, and they cleanse water of the

pollutants we add. We purposefully use some microorganisms to make

food (cheese, beer, sauerkraut), we put microorganisms to work in

sewage treatment plants, and we use them in biotechnology to produce

chemicals.

Naturally some microorganisms have learned to live on or in the human

body. Many of these microorganisms do no harm, and are even

beneficial because they compete with other microorganisms that might

cause disease if they could become established in or on our bodies.

The fecal indicator bacteria are such microorganisms; they are normal

inhabitants of the gastrointestinal tract of humans and many other

warm-blooded animals and in general, they cause no harm.

A few microorganisms (called pathogens) can cause disease in humans.

In order to cause disease, a pathogen must successfully invade some

part of the body and either produce more of itself or produce a

chemical (usually called a toxin) which interferes with normal body

processes. Whether or not a pathogen is successful in causing disease

is related to the health of the individual and the state of his or

her immune system, as well as to the number of pathogen cells

required to make the person ill. Some pathogens can cause disease

when only a few cells are present. In other cases, many cells are

required to make a person ill. Children and elderly persons are more

susceptible to many pathogens than are young or middle-aged adults.

Some pathogens live out their lives in the soil and water and only

cause disease under unusual circumstances. The microorganism that

causes tetanus is an example. This microorganism (a bacterium named

Clostridium tetani) lives normally in the soil. Clostridium tetani

grows in the body only in deep puncture wounds where air cannot

penetrate (termed anaerobic). In this environment it produces a toxin

which spreads throughout the body and may cause paralysis. Other

pathogens are more closely associated with humans and other warm-

blooded animals. These pathogens are transmitted from one organism to

another by direct contact, or by contamination of food or water. Many

of the pathogens which cause gastrointestinal disease are in this

category. Several human gastrointestinal pathogens produce toxins

which act on the small intestine, causing secretion of fluid which

results in diarrhea. In severe cases, such as cholera, the afflicted

person may die from loss of body fluids and severe dehydration. Cells

of the pathogen are shed in the feces, and if these cells contaminate

food or water which is then consumed by another person, the disease

spreads.

It is not unusual to find some fecal indicator bacteria and even some

pathogens in natural environments. The organism called Giardia

lamblia (a protozoan) is an example. This organism is found in the

gastrointestinal system of some wild mammals, and may enter water

through the feces of these mammals. The organism causes severe

diarrhea in humans. Persons who backpack or hike in wilderness areas

are advised to treat all water before drinking, even if it comes from

a pristine, clear, cold mountain stream. Therefore, the risk of

disease is not uniquely a result of the presence of human wastes in

the environment.

Nevertheless, in natural environments, organisms are relatively

dispersed, therefore wastes are also relatively dispersed. In

addition, natural wastes are composed of compounds natural to that

environment and microorganisms in the soil and water can degrade

those wastes and recycle them into usable forms. When the quantity or

type of waste exceeds the capacity of the microorganisms in soil and

water to degrade it, we call the waste pollution. The degradation

capacity of microorganisms in soil and water is challenged by extreme

amounts of wastes, as well as by unusual (often man- made) or toxic

compounds. It is difficult to live in an industrialized and urbanized

world and not produce localized concentrations of wastes. When human

fecal wastes are concentrated in the environment, we assume, for our

own protection, that the risk of transmission of pathogens may

increase, even though we may have no direct evidence of the presence

of a specific pathogen. It is for this reason that we monitor the

quality of our food and water, and establish personal hygiene and

public policies that attempt to prevent contamination in the first

place.