Advanced Search   
SFPUC Home   |   Site Index   |   Contact: Email & Phone   
  
At Your Service
  
Contracts & Bids
  
Water System Improvement Program
  
Water
  
Wastewater (Sewers)
  
Power
  
Natural Resources
  
Your Environment
  
About SFPUC

Bacteria Fact Sheets
Published: 12/04/2007  |  Updated: 12/04/2007
Published By: Water Quality

 SFPUC Image

Overview

Bacteria are small unicellular microorganisms, 1-5 micrometers (µm) in length or diameter.  All bacteria have relatively simple structures that include genetic material and structures enabling self replication. Most bacteria are one of three shapes:  rod-shaped (bacilli) spherical (cocci), or curved (spirilla) They have adapted to live and reproduce in a variety of environments including animals, humans, water, soil, and food. Most bacteria are effectively eliminated during water disinfection. Small numbers may, however, survive and enter the water distribution system. Some are present in sufficient quantity to infect individuals while others grow within consumer plumbing. The bacteria may then detach from the pipes and subsequently infect human beings. Not all bacteria are harmful, but the following potentially pathogenic bacteria may be of concern:

Anthrax

The San Francisco Public Utilities Commission (SFPUC) continues its commitment to provide safe, high quality drinking water through aggressive watershed protection and appropriate water treatment. While tap water is safe, it is not sterile. People with weakened immune systems may be more vulnerable to microbiological contaminants than others and should seek advice about protective measures, including drinking water, from their health care provider.

What is Anthrax?

Anthrax is a highly infectious disease caused by the Bacillus anthracis (B. anthracis) spore-forming bacteria. The rod shaped spores are 1 to 1.5 micrometers (µm) by 4 to 10 µm. Anthrax is typically a disease of hooved animals, however, it may be transmitted to humans. The three forms of the disease in humans are cutaneous (skin), gastrointestinal (ingestion) and pulmonary (inhalation).

Where is Anthrax Found?

B. anthracis is present in infected animals and animal products. Anthrax infection acquired naturally is through contact with infected animals or contaminated products. The incidence of naturally occurring anthrax is very low.

What are the Symptoms of Anthrax?

Symptoms for anthrax appear between two to seven days after infection. Symptoms are dependent on the route of infection as described below:

Cutaneous: Initially a raised itchy bump forms on the skin, similar to an insect bite, eventually turning black in the middle. Lymph glands may swell in the affected area.

Ingestion: Initial symptoms include nausea, loss of appetite, vomiting, fever, developing into abdominal pain, bloody diarrhoea and vomit, and shock.

Inhalation: Initial symptoms are similar to a common cold, rapidly progressing to severe breathing problems, and shock.  Death can occur within 1-2 days if untreated.

What is the Treatment for Anthrax?

Antibiotics such as penicillin, erythromycin, tetracycline, chloramphenicol are effective treatments for anthrax. Delaying treatment can lead to blood poisoning and death.

How is Anthrax Spread?

Anthrax is not typically spread by person-to-person contact. Anthrax can be contracted through the skin by handling contaminated animal products such as wool, hides, hair products, or by inhaling anthrax spores while handling the contaminated product. Gastrointestinal infection may also occur from eating undercooked meat from infected animals. Occupational exposure to infected animals or infected animal products is the most likely form of transmission, however, incidence of anthrax in animals is rare in the United States.

How Can I Protect Myself?

The Advisory Committee for Immunizations Practices (ACIP) recommends vaccination against anthrax for the following :

  1. Individuals who work with imported animal hides, furs, bonemeat, wool, animal hair (especially goat) and bristles;
  2. Individuals  who are employed in diagnostic or investigational activities that potentially involve contact with anthrax spores.

In addition, the Department of Defense recently required that men and women in the Armed Services be vaccinated against anthrax due to the potential for its use in biological warfare. Only healthy men and women between the ages of 18 and 65 should receive vaccinations.

For Further Information

Campylobacter

The San Francisco Public Utilities Commission (SFPUC) continues its commitment to provide safe, high quality drinking water through aggressive watershed protection and appropriate water treatment. While tap water is safe, it is not sterile.  People with weakened immune systems may be more vulnerable to Campylobacter than others and should seek advice about protective measures, including drinking water, from their health care provider.

What is Campylobacter?

Campylobacter is a family of bacteria, 1 to 5 microns in size, which causes a diarrheal disease known as campylobacteriosis. The bacteria replicates in the intestines of infected humans and animals, most commonly cattle and poultry, but also pets and other farm animals.

Where is Campylobacter Found?

Campylobacter is present in the feces of infected humans and animals. Surface waters such as streams, rivers and lakes may be contaminated with the bacteria, as well as unchlorinated drinking water, unpasteurized milk and food, especially chicken.

What are the Symptoms of Campylobacteriosis?

Symptoms for campylobacteriosis appear three to five days after swallowing the bacteria. Common symptoms include diarrhea with blood and mucus, abdominal pain, fever, nausea and vomiting. Severe cases may include a typhoid-like syndrome, arthritis or symptoms similar to acute appendicitis. Some people may not show evidence of the disease. If you have severe diarrhea for more than 4 days, you should ask your doctor to have your feces tested for Campylobacter. If you have a young child with severe diarrhea you should go sooner. Only a test of your feces will show if you have campylobacteriosis.

What is the Treatment for Campylobacteriosis?

Most people will recover on their own within 2-5 days, and symptoms usually do not last more than 10 days. Drink lots of fluids if you have diarrhea. In severe cases, a doctor may prescribe a short course of antibiotics.

How is Campylobacteriosis Spread?

Campylobacteriosis is contracted only by ingestion of the bacterium. It is generally transmitted from person to person or animal to person through the fecal-oral route and therefore the following precautions should always be taken.

How Can I Protect Myself?

  1. Always wash your hands with soap and water any time you might have touched human or animal feces, changed diapers, cleaned up feces, or gardened.
  2. Always wash your hands before eating.
  3. Avoid sex that may involve contact with feces.
  4. Know the source of your water: (a) do not drink or swallow water directly from rivers, lakes, streams, pools, or spas, (b) if you travel outside the United States you may want to avoid drinking water that has not been boiled or filtered.

If you are immunocompromised you should consider additional protective steps such as boiling your drinking water for one minute, which will kill any Campylobacter in it. You could also use a water filter certified by National Science Foundation (NSF) International to remove cysts or drink only bottled water certified by NSF or canned and bottled bubbly drinks.

For Further Information

Cholera

Cholera was prevalent in the United States in the 1800s, but has been virtually eliminated by modern water and wastewater treatment practices.  Outbreaks in the United States have generally been confined to food borne transmission caused by contaminated seafood brought to the U.S. by travelers.  Travelers to areas with epidemic cholera may be exposed to cholera bacterium and should take the necessary precautions. 

What is Cholera?

Cholera is an acute intestinal infection caused by the motile spiral or S-shaped bacterium Vibrio cholerae, 1 to 5 micron in size.

What are the Symptoms of Cholera?

Disease symptoms appear one to five days after exposure. Symptoms include a copious, painless, watery diarrhea and vomiting.

Most persons infected with V. cholerae do not become ill, although the bacterium is present in their feces for 7 to 14 days. When illness does occur, more than 90% of episodes are of mild or moderate severity and are difficult to distinguish clinically from other types of acute diarrhea. Less than 10% of ill persons develop typical cholera with signs of moderate or severe dehydration.

How is Cholera Spread?

Cholera is spread by contaminated water and food. Sudden large outbreaks are usually caused by a contaminated water supply. Only rarely is cholera transmitted by direct person-to-person contact. Marine shellfish and plankton are the main non-human reservoirs of V. cholerae. The El Tor strain can also survive in fresh water for long periods. Persons with asymptomatic infections play an important role in carrying V. cholerae from place to place, causing epidemics to spread.

What is the Treatment for Cholera?

Most cases of diarrhea caused by V. cholerae can be treated adequately by giving a solution of oral rehydration salts. In severe cases, an effective antibiotic can reduce the volume and duration of diarrhea.

What Can You Do to Prevent Cholera Infection?

Three elements are essential: hygienic disposal of human feces, an adequate supply of safe drinking water, and good food hygiene. Effective food hygiene measures include cooking food thoroughly and eating it while still hot; preventing cooked foods from being contaminated by contact with raw foods, contaminated surfaces or flies; and avoiding raw fruits or vegetables unless they are first peeled.

For Further Information

Coliforms Bacteria

Many drinking water sources contain varying levels of disease-causing microorganisms known as pathogens.  One of the primary objectives of the treatment of drinking water is the removal or reduction of these pathogens in order to ensure consumer safety.  Although most of the more problematic pathogens are identifiable, it is generally too cumbersome to measure each pathogen species on a regular basis.  Thus, other microorganisms which are more easily measured and which are typically found associated with pathogens are used to indicate the presence of harmful pathogens.  The most commonly used pathogen indicator is a group of microorganisms known as coliform bacteria.  Coliform bacteria have historically been used as indicators for pathogens, though their usefulness has been debated more recently.

Total Coliforms

Coliforms include a variety of microorganisms detected by a special laboratory procedure.   Coliforms typically originate from the intestines of humans and other animals. However because some species are naturally present in plant material or soil, the presence of coliforms does not necessarily indicate fecal contamination.  The total coliform test is useful for testing water (and foods) since it is inexpensive, fast, and can indicate potential microbial risks.   Its limitations include its lack of specificity for pathogenic organisms, and the fact that it can grow in water samples thereby giving rise to false positives.

Fecal Coliforms

A refinement on total coliform is to test for a subgroup: Fecal coliforms.  This test is more specific for the types of organisms which may cause disease.  The test, however, does not distinguish between human and animal sources.

E. Coli

A specific organism that can be detected in either total or fecal coliform test is Escherichia coli (E. coli).  Because it is so often found along with pathogens, it is a good indicator of potential pathogenic contamination.  While many E. coli cause no health problems, there are a few species that do cause disease.  One of them is Type O157:H7, which was implicated in disease outbreaks associated with undercooked hamburgers and unpasteurized apple juice. 

For Further Information

Escherichia Coli

The San Francisco Public Utilities Commission (SFPUC) continues its commitment to provide safe, high quality drinking water through aggressive watershed protection and appropriate water treatment.  While tap water is safe, it is not sterile.  People with weakened immune systems may be more vulnerable to E. coli than others and should seek advice about protective measures, including drinking water, from their health care provider.

What is Escherichia Coli O157:H7?

Escherichia coli (E. coli) O157:H7, first recognized as a cause of illness in 1982, is one of hundreds of strains of the bacterium E. coli.  Although most strains are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin and can cause severe illness.

E. coli O157:H7 is an emerging cause of foodborne illness.  The Centers for Disease Control estimates that 73,000 cases of infection occur in the United States each year.  Most illness has been associated with eating undercooked, contaminated ground beef.  However, infection can also occur after drinking raw milk and after swimming in or drinking sewage-contaminated water.

What Illness Does E. Coli O157:H7 Cause?

E. coli O157:H7 infection often causes severe bloody diarrhea and abdominal cramps; sometimes the infection causes nonbloody diarrhea or no symptoms.  Usually little or no fever is present, and the illness resolves in five to ten days. Symptoms will normally appear 12 to 60 hours after exposure.

In two percent to seven percent of infections, particularly in children under five years of age and in the elderly, the infection can also cause a complication called hemolytic uremic syndrome, in which the red blood cells are destroyed and the kidneys fail.

Infection with E. coli O157:H7 is diagnosed by testing stool samples on sorbitol-MacConkey (SMAC) agar for this organism.  All persons who suddenly have diarrhea with blood should get their stool tested for E. coli O157:H7.

How is the Illness Treated?      

Most persons recover without antibiotics or other specific treatment in five to ten days.  There is no evidence that antibiotics improve the course of disease, and it is thought that some antibiotic treatments may precipitate kidney complications.  Antidiarrheal agents, such as loperamide (Imodium), should also be avoided.

Hemolytic uremic syndrome is a life-threatening condition usually treated in an intensive care unit.  Blood transfusions and kidney dialysis are often required.  With intensive care, the death rate for hemolytic uremic syndrome is three to five percent.

How is E. Coli O157:H7 Spread?

The organism can be found on a small number of cattle farms and can live in the intestines of healthy cattle.  Meat can become contaminated during slaughter, and organisms can be thoroughly mixed into beef when it is ground.  Bacteria present on the cow's udders or on equipment may get into raw milk.

Eating meat, especially ground beef, that has not been cooked sufficiently to kill E. coli O157:H7 can cause infection.   Contaminated meat looks and smells normal.  Although the number of organisms required to cause disease is not known, it is suspected to be very small.

Drinking unpasteurized milk or juice and swimming in or drinking sewage-contaminated water can also cause infection.       

Bacteria in stools of infected persons can be passed from one person to another if hygiene or hand washing habits are inadequate.  This is particularly likely among toddlers who are not toilet trained.  Family members and playmates of these children are at high risk of becoming infected.

Young children typically shed the organism in their feces for a week or two after their illness resolves.  Older children rarely carry the organism without symptoms.

What Can You do to Prevent E. Coli O157:H7 Infection?

  • Cook all ground beef or hamburger thoroughly.   Make sure that the cooked meat is gray or brown throughout (not pink), any juices run clear, and the inside is hot.
  • If you are served an undercooked hamburger in a restaurant, send it back for further cooking.
  • Consume pasteurized milk and milk products.   Avoid raw milk.
  • Consume pasteurized juices.
  • Make sure that infected persons, especially children, wash their hands carefully and frequently with soap to reduce the risk of spreading the infection.
  • Drink municipal water that has been treated with adequate levels of chlorine or other effective disinfectants.

For Further Information on E. Coli O157:H7

  • Call the SFPUC Water Quality Bureau for water quality information (650-652-3127 or 877-737-8297)
  • Call the Environmental Protection Agency (EPA) Safe Drinking Water Hotline for information on water quality and associated regulations (800-426-4791)
  • Call the Centers for Disease Control and Prevention (CDC) Division of Bacterial and Mycotic Diseases if you would like further information on E. coli (404-639-3311)

Follow the links below for additional E. coli information

Helicobacter pylori

The San Francisco Public Utilities Commission (SFPUC) continues its commitment to provide safe, high quality drinking water through aggressive watershed protection and appropriate water treatment. 

What is Helicobacter pylori?

Helicobacter pylori (H. pylori) is a rod-shaped bacillus, 1 to 5 microns in size, that is found throughout the world. This stomach infection was first reported in 1986, and is now estimated to occur in approximately fifty percent of the world population. It is thought to be the most common cause of chronic bacterial infection in humans. Many infected individuals do not exhibit symptoms, but still have an inflammation of the stomach lining which is called gastritis.

How can Helicobacter pylori Affect My Health?

H. pylori causes both chronic gastritis and duodenal ulcer disease. However, duodenal ulcer disease is not common. Gastritis is known to cause ulcers, other digestive complaints, and conceivably cancer of the stomach. The incubation period between infection and the onset of symptoms is 5 to 10 days, however, the majority of people infected with H. pylori do not exhibit symptoms. If left untreated, H. pylori infections will remain in the host through life. Diagnosis of H. pylori infection is done via a blood test. An upper gastrointentinal series examination can also be done to check for cancer in those infected with H. pylori.

What is the Method of Treatment for H. pylori?

The standard method of treatment for H. pylori includes metronidazole, amoxacillin, and omeperazole. Infected people should also take a bismuth-containing compound. An additional blood test should be done approximately 8 weeks after treatment to test for H. pylori. If the infection is resistant to the treatment, alternative treatment including the use of clarithromycin, and tetracycline, can be used.

How is H. pylori Spread?

The only known reservoir for H. pylori is humans. Currently, the mode of transmittal for H. pylori is not known. Ingestion, however, is the most likely route of the infection via oral-oral or fecal-oral transmission.

How Can I Protect Myself?

  1. Always wash your hands with soap and water any time you might have touched human feces, changed diapers, or cleaned up feces. 
  2. Always wash your hands before eating.
  3. Avoid sex that may involve contact with feces.

For Further Information 

Legionella

The San Francisco Public Utilities Commission (SFPUC) continues its commitment to provide safe, high quality drinking water through aggressive watershed protection and appropriate water treatment.  While tap water is safe, it is not sterile.  People with weakened immune systems may be more vulnerable to Legionella than others and should seek advice about protective measures, including drinking water, from their health care provider. 

What is Legionella?

Legionella is a small bacterium found almost everywhere.  There are many different types, but only one, Legionella pneumophila, serogroup 1, is thought to account for the disease that caused an outbreak of pneumonia at the 1976 Convention of the American Legion resulting in 182 cases and 29 deaths.

How Does One Become Exposed?

The primary source of Legionella appears to be water.  The key exposure route is, however, not drinking of tap water but inhalation of aerosols associated with hot water systems, air conditioning cooling towers, evaporative condensers, and whirlpool spas.  Legionella has also been isolated from hot and cold water taps and from creeks, ponds, and surrounding soil.  Legionella is not transmitted from person-to-person.

What Happens if One is Exposed?

For many people exposure to Legionella may have no effect, for others it may cause mild symptoms such as headache and fever, while a few may become seriously ill.  Infections most often occur in middle-aged and older persons, particularly those who smoke or have chronic lung disease.  Also at increased risk are immunocompromised individuals such as those with cancer, diabetes, or AIDS.  Symptoms of the disease will usually appear 2 to 10 days after exposure.

What are the Disease Symptoms?

Infection by Legionella (i.e. Legionellosis) can cause Legionnaires' disease or Pontiac Fever.  With both, fever and chills generally develop within a day.  A dry cough, abdominal pain, diarrhea, muscle aches, tiredness, and loss of appetite are common.  Pneumonia is frequently associated with Legionnaires' disease but not with Pontiac Fever.  Individuals with Pontiac Fever generally recover in 2 to 5 days without treatment.

Is it Treatable?

Legionellosis is readily treated by antibiotics (e.g., rifampicin and erythromycin) which are, in most instances, administered intravenously.

What's Being Done to Control Legionella?

Water treatment practices of disinfection and filtration are the industry standard and deliver safe, potable water.  Even with these processes, however, small amounts of Legionella can survive, and given the proper conditions, can colonize ends of plumbing systems.  Consequently, a key element for controlling Legionella is the improved design and maintenance of cooling towers and plumbing systems to limit Legionella growth and aerosolization.   In addition, increasing the temperature of hot water systems may limit exposure to Legionella.   Other measures include super-chlorination of plumbing systems and maintaining chlorine residuals in decorative fountains.

While most of the airborne infections have been associated with buildings, there are some precautionary measures that can also be taken in the household.  These include: cleaning the shower head by soaking in household bleach for 15-minutes every month and raising the temperature of the hot water heater to 155 oF.

For Further Information

Mycobacterium Avium Complex

The San Francisco Public Utilities Commission (SFPUC) continues its commitment to provide safe, high quality drinking water through aggressive watershed protection and appropriate water treatment.  While tap water is safe, it is not sterile.  People with weakened immune systems may be more vulnerable to infection by Mycobacterium Avium Complex (MAC) than others and should seek advice about protective measures, including drinking water, from their health care provider.

What is MAC and How Does One Become Exposed?

Mycobacterium avium Complex (MAC)  is comprised of two different bacterial species: Mycobacterium avium and Mycobacterium intracellulare.  MAC is found almost everywhere.  There are many different types, several of which may cause disease. The sources of MAC are food (e.g., eggs, milk, cheese) soil and water.  The water exposure route is both drinking of tap water and inhalation of aerosols associated with hot water systems, air conditioning cooling towers, evaporative condensers, and whirlpool spas.  MAC has also been isolated from hot and cold water taps and from creeks, ponds, and surrounding soil.

What Happens if One is Exposed?

Infections occur most often in the immunocompromised.  For many people exposure to MAC will have no effect, for others it may cause respiratory tract infections, while for a few it may cause serious illness.  Infections most often occur in middle-aged and older persons, particularly those who smoke or have chronic lung disease.  Also at increased risk are immunocompromised individuals such as those with cancer, diabetes, or AIDS.

What are the Disease Symptoms?

 Infection by MAC can cause wound infections, skin ulcers, pulmonary disease or systemic blood-borne disease.  With the latter, the symptoms include fever and drenching sweats, fatigue and weight loss.  Most immunocompetent people will recover on their own, however antibiotics can be effectively used if necessary.  Individuals with severely compromised immune systems generally require medications to manage the disease.

Recommendations

Because MAC is found in food, water, and soil there is no easy way to avoid it.   The San Francisco Department of Public Health's (SFDPH) concern with MAC is for persons with known immunosuppression such as AIDS.  The SFDPH does not recommend any special precautions to reduce exposure to MAC from any source, including water.   Instead, the Centers for Disease Control and Prevention (CDC) recommends drug prophylaxis for susceptible individuals, treatment for clinically recognized disease, and anti-viral therapy for those with HIV disease.

For Further Information




Back to Top  


 
 
Visit sfgov.org the official site of the City and County of San Francisco
Copyright © 2008, San Francisco Public Utilities Commission

Privacy Policy  |   SFPUC Home  |   Site Index  |   Contact: Email & Phone