Here’s the reality: under normal conditions, E. coli and coliform bacteria are not airborne. They do not evaporate or become aerosolized unless subjected to significant force, such as high-pressure splashing or mechanical aerosolization. This means that bacterial air sampling and surface swabbing in areas not directly impacted by sewage contamination might lead to misleading results.

Effective sampling of E. coli involves targeted methodologies:
1️⃣ Focus on direct sources of contamination (e.g., sewage-impacted surfaces).
2️⃣ Use sterile swabs for surface testing in areas of concern.
3️⃣ Employ water sampling for suspect reservoirs, following EPA or CDC guidelines.

While air sampling has its place in identifying certain contaminants, using it to detect E. coli in unrelated areas often results in unnecessary effort and misallocated resources.

Non-tuberculous Mycobacteria are mycobacteria other than Mycobacterium tuberculosis and M. leprae, and are also referred to as atypical mycobacteria, mycobacteria other than tuberculosis (MOTT), or environmental mycobacteria.

Where Are Non-tuberculous Mycobacteria Commonly Found?

Non-tuberculous Mycobacteria typically are free-living environmental saprophytes. Some free-living Mycobacteria are opportunistic human pathogens and there is evidence that they are usually transmitted by inhalation, inoculation and ingestion from environmental sources. Soil, surface water, ground water and sea water have been described as natural habitats of environmental Mycobacteria. In addition, artificial habitats such as tap water and sewage sludge are colonized by a considerable spectrum of mycobacterial species. Aquatic Mycobacteria tend to colonize biofilms at air-water and solid-water interfaces and the latter seem to be an important proliferation site in oligotrophic habitats.

Non-tuberculous Mycobacteria (NTM) can form difficult-to-eliminate biofilms. Biofilms are collections of microorganisms that stick to each other, and adhere to surfaces in moist environments, such as the insides of plumbing in buildings. As opportunistic pathogens, NTMs can cause infections in a wide variety of body sites, most commonly the lungs and in the following areas: skin and soft tissue, device-associated infections, lymph nodes, blood or other usually sterile locations in the body.

Though opportunistic pathogens, NTMs can infect anyone, but certain groups face a higher risk, particularly individuals with underlying lung disease or weakened immune systems. While NTMs are generally not transmitted from person to person, there have been reported cases of person-to-person transmission of Mycobacterium abscessus in patients with cystic fibrosis.

It is crucial for health and safety and infection control officials in hospitals to understand the risks associated with NTM infections and the importance of testing for NTM in hospital environments. By testing for NTM, hospitals can identify potential sources of infection and take appropriate measures to prevent the spread of NTM infections. This can help reduce the risk of NTM infections in patients, especially those weak immune system.

Why Test for Non-tuberculous Mycobacteria (NTM)?

NTM, often underestimated, can lurk in hospital water systems, equipment, and even in the air. It is important for hospitals and homecare facilities to test for non-tuberculous mycobacteria because these bacteria can cause serious infections in patients, especially those who are immunocompromised. By testing for NTM, hospitals and homecare facilities can identify potential sources of infection and take appropriate measures to prevent the spread of NTM infections. This can help reduce the risk of NTM infections in patients, and improve patient outcomes.

At Mold & Bacteria Consulting Laboratories we have the expertise to test and identify non-tuberculous mycobacteria from hospital water and other environments.

It is estimated that one-third of waterborne disease outbreaks are caused by pools and hot tubs. It is important to note that some people are more likely to get sick from exposure to bacteria and parasites in recreational water than others.

Bacteria in hot tubs, spas and swimming pools and the risk of sickness or infection to users

The risk of sickness or infection is often associated with faecal contamination of the water. The source of contamination could be faeces released by users, contaminated source water or, in case of outdoor pools, contamination by animal faeces. Many of the infection outbreaks related to swimming pools can be prevented or reduced through proper maintenance.

Assessing the microbial quality of pools, spas and hot tubs

Microbial quality of pools, spas, hot tubs and similar environments is assessed using indicator microorganisms. Indicator microorganisms include heterotrophic plate count(HPC). HPC is a general measure of non-specific microbial levels, faecal indicators (such as thermotolerant coliforms, E. coli), Pseudomonas aeruginosa, Staphylococcus aureus and Legionella spp. HPC, thermotolerant coliforms and E. coli are indicators in the strict sense of the definition. The results of the microbiological test provide valuable data regarding the microbial quality of the pool water.

As health risks in pools and similar environments may be faecal or non-faecal in origin, both faecal indicators and non-faecally-derived microorganisms (e.g. P. aeruginosa, S. aureus and Legionella
spp.) should be tested. Faecal indicators are used to monitor for the possible presence of faecal contamination; HPC, Pseudomonas aeruginosa and Legionella spp. can be used to examine growth, and Staphylococcus aureus can be used to determine non-faecal contamination. The absence of these organisms, however, does not guarantee safety, as some pathogens are more resistant to treatment than the indicators, and there is no perfect indicator organism.

Testing Services for Bacteria in hot tubs, spas and swimming pools.

The owner of a swimming pool, spa or hot tub, and any pool service company they hire, have an obligation to safely maintain and operate their pool, spa or hot tub. Parasites, bacteria, and other microorganisms can thrive in even well maintained pools, spas or hot tubs. Regular testing of the water is therefore recommended.

Mold & Bacteria Consulting Laboratories offers the following testing microbial quality tests:

Whirlpools, spas, hot tubs

• Pseudomonas aeruginosa
• Heterotrophic plate count
• E. coli/Coliforms
• Legionella sp.

Swimming pools

• E. coli/Coliforms
• Fecal Coliforms
• Staphylococcus or Staphylococcus aureus
• Pseudomonas aeruginosa
• Fecal Streptococci or Fecal Enterococci
• Candida albicans

Skin bacteria could be used to identify you just like your fingerprints. Studies on all the microbes (a.k.a, microbiome) that live in and on the human body suggest that humans serve as hosts for a vast diversity of microorganisms.

Each human being supports trillions of microorganisms and any 2 people share only about 13 percent of their skin bacteria population. While a few of the skin bacteria are harmful and can cause serious illnesses, majority are harmless and beneficial. In healthy individuals, the harmless bacteria (commensal skin bacteria) provide protection from disease causing bacteria (pathogens).

For example, Staphylococcus epidermidis produces antimicrobial substances that help fight pathogenic bacteria and Propionibacterium acnes uses lipids from the skin to generate short-chain fatty acids that can similarly provide protection from harmful microorganisms.

How skin bacteria could be used to identify you

The diversity of bacterial populations living on our skins is much higher (at molecular level) than previously thought and it varies widely from person to person. Recent research has revealed that any two people, on average, share only about 13 percent of their bacterial populations, which also can vary in quantity.

The other 87 percent of the bacteria types are so distinct they act like a bacterial fingerprint and could be used to identify the individual person. When we sleep on beds, shake hands, touch things such as door knobs, ATM keys, a computer keyboard or mouse, we leave behind an identifying trace of bacteria.

What’s more, analysis of skin bacteria could be used to determine how much individuals in a family interacted, what rooms they used, and even when they had last been to one part of the house or another. The skin bacteria population profile has obvious applications in forensic science. The profiles could come in handy to track down criminals or lost individuals.

Another practical application could be to differentiate between identical twins. While identical twins may have the same DNA, chances are that they only share about 13 per cent of their body bacteria populations.

Challenges facing the use of skin bacterial signatures for identification of people

One challenge is that traditional methods of bacteria identification cannot be used to adequately differentiate bacterial populations in or on human bodies. Advanced molecular methods, only available in a few research labs are required. Secondly, if more than one person left their bacteria on an object, it is not yet possible to sort out their mixed-up bacterial signatures.

Conclusion

While use of skin bacteria to identify you is still years away, once perfected, the technique eventually could become an additional forensic tool, along with others like fingerprint and DNA analysis.

References

1. Fierer N, Lauber CL, Zhou N, McDonald D, Costello EK, Knight R. Forensic identification using skin bacterial communities. Proc Natl Acad Sci U S A. 2010 Apr 6; 107(14):6477-81.

Terms like flesh-eating or necrotizing have been used because the bacterial infection produces toxins that destroy tissues such as muscles, skin, and fat. However, the bacteria does not “eat” the flesh as the name suggests. GAS are the same bacteria that cause strep throat.

Flesh-eating bacteria infects people through wounds, minor cuts, insect bites or abrasions . The bacteria grow and release toxins that destroy tissues and affect blood flow to the affected areas. At advanced stage the bacteria enter the blood system and rapidly spread throughout the body. The majority of flesh-eating bacteria disease cases begin with an existing infection, most frequently on an extremity or in a wound.

Many other bacteria including some that thrive in oxygen-limited environments, for example inside the human body have been found to cause the fresh-eating bacteria disease.

Other bacteria associated with flesh-eating bacteria disease are Aeromonas hydrophila and Vibrio vulnificus.

Recent cases of flesh-eating bacteria disease

Recent cases of flesh-eating bacteria involved the bacterium Vibrio vulnificus. Two people in Florida got the infection and one of them died. People usually come into contact with Vibrio vulnificus by consuming raw shellfish and swimming in water with open wounds.

Symptoms of Vibrio vulnificus include vomiting, diarrhea, abdominal pain, ulcers and the breakdown of skin.

Who is at risk of flesh-eating bacteria infection?

Generally, people with weakened immune systems such as those who suffer from liver disease and HIV Aids are at higher risk of infection. Studies have shown that risk of Vibrio vulnificus infection in people with pre-existing medical conditions were 30% higher than the general population. Treatment of people infected by Vibrio vulnificus through open wounds may involve amputation to ensure recovery.

Treatment of flesh-eating bacteria disease

Treatment of an infection caused by flesh-eating bacteria involves antibiotics and surgery to drain the sore and remove dead tissue.

Mold & Bacteria Consulting Labs (MBL) offer both a comprehensive bacteria testing service along with training and education resources on mold and bacteria. If you have questions about this article, please contact us to discuss further.

When we think of Legionella and Legionnaires’ disease, what comes to mind are cooling towers and other man-made water systems. Rarely do we think of compost. However, compost may contain the potentially deadly Legionella bacteria.

In fact, cases of legionellosis caused by Legionella bacteria in compost have been reported worldwide. In October 2013, a case of legionellosis linked to compost exposure was reported in Richmond, British Columbia.

Legionellosis is a term used for any disease, caused by Legionella. Two forms of legionellosis are common. A mild form known as Pontiac Fever and a more severe form of pneumonia known as Legionnaires’ Disease. The association between commercial compost and legionellosis was established in Australia in 1989.

Since then, Legionella longbeachae, the cause of Legionnaires’ disease associated with compost, has been isolated from fresh potting media. Legionella longbeachae is less common in North America and Europe than Legionella pneumophila. The species got its name from the first recognized case of Legionnaires’ disease caused by Legionella longbeachae, which occurred in 1980 in Long Beach, California.  

Unlike other Legionella bacteria, Legionella longbeachae is not found in water. It causes legionellosis symptoms ranging from mild flu-like illness to severe pneumonia and death.

Legionella pneumophila is the species responsible for the first documented outbreak of Legionnaires’ disease in 1976. It is the cause of the majority of legionellosis cases in the world and it’s commonly found in water.

Exposure to Legionella bacteria

The Legionella bacteria are not transmissible from person to person. How Legionella longbeachae are spread is not well known. It is speculated that the bacteria is inhaled in or spread from hands contaminated by handling potting mix to mouth. Exposure to Legionella pneumophila is primarily airborne through aerosolized water containing the bacteria. Legionella containing aerosols can be produced by:

• showers;
• cooling towers;
• air conditioning systems cooled by water;
• humidifiers;
• whirlpool spas.

Compost as a source of Legionella bacteria

Studies have demonstrated the diversity of Legionella species found in commercial composts and potting soils. The most commonly isolated non-pneumophila Legionella species from compost are Legionella longbeachae, Legionella bozemanae, Legionella micdadei, Legionella dumoffii and Legionella feeleii. Others include Legionella bozemanii, Legionella sainthelensi, and Legionella micdadei.

While cases of legionellosis associated with compost are uncommon in North America, they are quite common in UK and across Europe , Australia and New Zealand.

Our team here at Mold & Bacteria Consulting Laboratories offer a comprehensive bacteria screening and analysis (including Legionella). You can contact us by email or telephone to discuss your case further.

But have you ever thought about the air quality inside of your car? Well, it is something to consider…A ventilation system and passenger cabin of almost every vehicle on the road is a great home for germs and harmful allergens. You could be putting your health at risk without even knowing it.

Considering a fact that the average driver in North America spends approximately 1.5 hours per day in their vehicle, it is important to think about the hygiene of your personal transport. Hygiene should not be just a consideration in the public transport, house, school or office where we all know germs may be living.

Yes, you must also consider your car when creating a hygienic environment for you and your family. Studies have shown that the air inside of your car can be worse than the air you are breathing at home or at work.

You probably have read so many times that public transport carries thousands of germs. What would you think if you read that your car can also carry thousands of germs? Actually, there are excellent conditions inside of your car for germs to breed.

You are so busy and you maybe spending so much time inside your vehicle; there are drinks, food, children, pets, it is maybe your mobile office area or a changing room… great home for “little germ buddies”. They get into the car and multiply. If left to multiply, there could be millions of germs turning your car to unsafe environment.

According to a study conducted by Dr. Chuck Gerba, a University of Arizona microbiologist who’s been studying germ hot spots for years, “cars are the moldiest of all forms of transportation…because people aren’t really cleaning or disinfecting these areas.” Gerba found that the areas of the car with the most germs were the dashboard, change holder, wherever coffee was kept, car seats, floors and door handles.

There were even some pathogens identified such as E. coli, Salmonella, Campylobacter or MRSA. And the most surprising was the mould found on the child safety seat. The cars with children’s and pet’s passengers are usually dirtier and logically have higher bacteria counts which puts children and pets at a greater health risk.

Other source of contamination is through the ventilation system. Every time you turn on the fan, you and your passengers are breathing the air that gets into the passenger cabin through the ventilation system. This air carries over many “unwanted passengers” like germs and mould spores, road dust, vehicle emissions, pollutants and greenhouse gases. Some of them are linked to lung cancer. Many researchers confirmed that the climate control air blowers in the older cars are causing higher levels of germs contamination which could have connection with poorly-functioning air cabin filters.

Moulds, bacteria and viruses love the damp and dark environment where they are able to breed. They can find all these conditions in today’s modern ventilation systems and air-tight cars which work almost like incubators. Microorganisms such as moulds are able to release their harmful spores and mycotoxins into the passenger compartment and cause many adverse health effects (Sick Car Syndrome) such as:

• Eye, nose and throat irritation
• Sinus problems
• Frequent cold symptoms and headaches
• Fatigue
• Increased asthma attacks

Severe health effects from moulds are mostly experienced by immunocompromised persons, infants and young children, pregnant women and elderly people. Health problems always depend on the amount of mould present, the length of exposure and an individual’s immune system response among other factors. Getting rid of germs now can help you and your family avoid health problems in the future.

References

1. http://www.misthealthyair.org

2. http://aqium.com.au

3. http://www.globalshieldsolutions.com

4. http://www.keepincool.com.au

5. http://www.cabinfresh.com

Filamentous bacteria can be a problem in wastewater treatment. Wastewater treatment is essential for human health and environment, as well as to protect and maintain the environment from the distribution of pollution and water-borne diseases.

Human sewage and waste from industries are the main sources of wastewater. Biological wastewater treatment is the largest and most commonly biotechnology method in the world. It is an important part of wastewater treatment plants, in which different types of microorganisms are used in the processing and cleaning of wastewater.

Microorganisms are able to breakdown the organic waste content and use them as a food and energy source to grow and multiply in aerobic conditions.

The individual organisms clump and flocculate together in flocs flake-like structures (which contain alive and dead cells of microorganisms and there metabolic products), around the suspended organic material they feed on, to form larger masses that settle out of the water and forms an active mass of microbes called “activated sludge”. The wide majority of the wastewater treatment plants are based on the activated sludge principle.

The biological floc is composed of bacteria, fungi and protozoa. Bacteria involve around 95% of the total microbial population of the activated sludge and they are essential for the degradation of organic substances in wastewater treatment systems.

What are Filamentous Bacteria?

Filamentous bacteria are normal components of activated sludge biomass. The existence of some filamentous bacteria is important and helpful for good floc formation to a biomass. Filamentous  bacteria grow in long thread-like strands, whose cells do not  separate from each other after cell division and therefore grow in the form of filaments. Then, they connect with each other to form a mesh that is the most important part in floc formation and causes the separation of a fluid or removal of sediment from a fluid.

Filamentous bacteria can provide a support structure for other bacteria to attach to as they form floc and it serves as the backbone of floc formation and settling. However, these bacteria can be dominated and compete with the floc-forming bacteria under a specific condition. The excessive growth of these bacteria can cause potential problems with the sludge settling that reduce the efficiency of the wastewater treatment plants.

How Filamentous Bacteria Affect Wastewater Treatment

Bulking and foaming are considered the major problems usually happening worldwide in the operation of activated sludge systems, which can affect continuously or seasonally in the process of biological wastewater treatment plants. Bulking sludge is a condition defined by solids with poor or bad settling and thickening characteristic. Usually this is caused by an excessive and uncontrolled growth of different types of filamentous bacteria, which interfere with the concentration settling of activated sludge in wastewater treatment plants.

Filamentous bulking is often associated with changes in physical and chemical characteristics of the wastewater process. Foaming is a serious issue caused by increase of certain types of filamentous bacteria. Foaming can lead to major operational problems; hazardous working conditions, and affects on solid separation in wastewater plants. Foaming is characterized by the formation of a sticky, thick, firm and brown scum.

It floats and accumulates on surfaces of the tanks; where the foam can also overflow onto walkways and surrounding areas, creating severe difficulties and risk to operation and environment.

Microbiological investigations found 25 common types of filamentous bacteria in activated sludge. Different types of filamentous bacteria in the activated sludge have been described. A survey of bulking activated sludge plants in the U.S. has found approximately 15 major types of filamentous microorganisms are responsible for bulking and foaming.

The dominant types of filamentous bacteria depend on the nutrient condition in the wastewater system. Nocardia spp. is one of the main filamentous bacteria, which is responsible for foaming. Microthrix Parvicella, Nocardia amarae, Nostocoida limicola, Alcaligenes paemba, Alcanivorax, borkumensis, Thiothrix spp, Sphaerotilus natans, Beggiatoa spp. and Haliscomenobacter hydrossis, are also some of the most common filamentous bacteria that cause these same problems.

Controlling Filamentous Bacteria in Wastewater Treatment

Identification of filamentous bacteria is an important method because each type of these filaments can lead to a specific problem. Identifying the dominant species helps to find the solution and to control the problem. The identification of filamentous bacteria is based upon taxonomic keys.

Wet mount preparation is used to observe certain morphological characteristics such as; motility, branching, filament shape, attached growth, filament diameter, septa or transverse walls, cell shape, presence of a sheath and granules, under phase contrast and bright field microscope. Further staining reactions can help detect the presence of these microorganisms, such as; Gram stain, Neisser stain and Sulphur stain. However, the majority of filamentous bacteria in activated sludge are still unidentified beyond these simple characteristics.

Filamentous bacteria are of major concern today because of its involvement in bulking and foaming problems at wastewater treatment plants in all of the world, which influence the treatment activity and efficiency. Early detection of these problematic bacteria is needed in the wastewater treatment market.

At MBL Laboratories, we offer numerous analytical services in the detection, identification and enumeration of mould and bacteria in air, bulk, (solid and fluid) and cultures collected from homes, and work environments, using high level of scientific knowledge and methods.

For further information please contact us at:
Mold & Bacteria Consulting Laboratories
1020 Brevik Place, Unit 1A
Mississauga, ON L4W 4N7
Office: 905-290-9101 Toll-free: 1-866-813-0648
Fax: 905-290-0499

Georget Shamoon, PhD.
(Senior Microbiologist)

Over 90% of Legionnaires’ disease cases are caused by Legionella pneumophila. The first recorded outbreak of Legionnaires’ disease was in 1976 in Philadelphia, Pennsylvania, USA where several people who went to a convention of the American Legion got infected and 35 of them died.

Another outbreak is however believed to have occurred in the same venue in 1974. Since the 1976 outbreak, more and more cases of Legionnaires’ disease outbreaks have been reported in other parts of the world including Australia, United Kingdom, The Netherlands, Spain, Canada, Norway, New Zealand and German. Medical experts say that there is a general increase in the number of Legionnaires’ cases in North America. cases have significantly increased over the last decade.

Is Legionnaires’ Disease a Problem in Canada?

A search for Canadian national statistics for Legionnaires disease or Legionella did not show any records but according to Health Canada, the average number of reported cases of Legionnaires’ disease is generally less than 100 per year. However the actual number of cases is thought to be much higher, as many people with pneumonia may not be tested for infection with Legionella. 

Medical experts say cases of legionnaires’ disease have steadily increased in North America and Europe for the past decade. According to the public health officials, by July 2013, Toronto had five times as many cases of legionnaires’ disease within the past six weeks compared to the same time in 2012.

Single cases of Legionnaires’ disease are more common than out-breaks. Outbreaks occur in large institutional buildings, especially hotels and hospitals, or on cruise ships. There has been 2 major outbreaks of Legionnaires’ disease in Canada.

The first was in late September 2005 when one hundred and twenty-seven residents of a nursing home in Toronto were infected with Legionella pneumophila and within a week, 21 of the residents had died. The source of the outbreak was traced to the air-conditioning cooling towers on the nursing home’s roof.

More recently in September 2012, there was an outbreak of Legionnaires’ disease in Quebec City, Quebec. A hundred and eighty (180) people were affected and 13 of them died. This outbreak was associated with contamination of water in industrial cooling towers.

Therefore Mold & Bacteria Consulting Laboratories conclude that Legionnaires’ disease is becoming a problem in Canada. As part of due diligence, institutions operating hot and cold water systems should considered monitoring for Legionella bacteria on a regular basis.

For sample analysis please click Legionella Testing Laboratory

Sewage backup could lead to sewage contamination of the occupied spaces.

Exposure to sewage contamination increases the risk of contracting diseases of the digestive system and other related illnesses. Potential disease causing organisms in sewage contamination include Escherichia coli, Salmonella, and Shigella.

Testing for all possible disease causing microorganisms (pathogens) after sewage backup could be expensive, tedious and time consuming.

Therefore, the detection of indicator bacteria is more practical than direct pathogen detection because the former are considered to be normal, non-pathogenic intestinal inhabitants that are present in feces in much higher numbers than pathogenic microorganisms. The preferred indicator bacteria for sewage contamination are total coliforms, fecal coliforms and Enterococcus.

Sources of sewage contamination may include raw sewage backup, severe flooding and leaking sewer lines or septic tanks. To determine the potential health risks from sewage contamination swab samples could be collected and tested for total coliforms, fecal coliforms and Enterococcus.

Sampling Procedure for total coliforms, fecal coliforms and Enterococcus

Sampling for indicator organisms can be performed before and after clean up. Sampling after cleanup is recommended to determine if the cleanup was successful.

1. Wear suitable gloves
2. Using a measuring tape, measure an area of approximately 100 cm2 of the surface suspected to be contaminated with sewage.
3. Collect a swab sample by removing a sterile, rayon (non-cotton) swab from a sterile tube. If the surface to be tested is dry, moisten the swab by inserting it into the tube which contains a sponge soaked with sterile buffer.
4. Swab the selected surface by rolling the swab back and forth across the surface with several horizontal strokes, then several vertical strokes.
5. After sampling, return the swab to the sterile tube (with the sponge) and label the sample
6. Collect a control sample from a non-contaminated area by repeating steps 2 to 5.
7. On the chain of custody clearly indicate what indicator organisms you want tested, i.e., total coliforms, fecal coliforms, E. Coli and/or Enterococcus. The section on results interpretation (see below) will help you decide what to test for. Bacterial testing is time sensitive so samples should be sent to the laboratory within 24 hours of sample collection if possible and should be shipped with an ice pack.

How to interpret positive sewage results

Positive sewage results should be interpreted with caution since not all coliforms are of fecal origin.

Total Coliforms

Coliforms are common in the intestines of animals including human beings and hence they end up in sewage. They are also present in the environment as part of the natural microflora. These non-fecal coliforms can potentially cause false positive results when testing environmental samples.

Therefore positive tests for total coliforms do not necessarily indicate sewage contamination. For recreational waters, total coliforms are no longer recommended as an indicator. For drinking water, total coliforms are still the standard test because their presence indicates contamination of a water supply by an outside source.

Fecal Coliforms

The term “fecal coliform” is rather misleading since not all bacteria found in this group are of fecal origin. Fecal coliforms include bacteria such as E. coli, Klebsiella, Enterobacter, and Citrobacter.

With the exception of E. coli, these bacteria could also be associated with plants. Therefore, while the fecal coliform test is more specific than the total coliform test in indicating potential sewage contamination, this test is also subject to giving false negatives.

Escherichia coli (E. coli)

As mentioned above the E. coli belong to the fecal coliform group. Presence of E. coli is a reliable indication of fecal or sewage contamination. However, E. coli has also been isolated from soil suggesting that it may not be 100% reliable indicator of fecal or sewage contamination.

Enterococcus

Enterococci are a subgroup within the fecal streptococcus group. Enterococci are typically more human-specific than the larger fecal streptococcus group. EPA recommends enterococci as the best indicator of health risk. They are rarer than the coliforms in the environment and are always present in the feces of warm-blooded animals.

Research has indicated that enterococci might be a more stable indicator of sewage contamination than E. coli and fecal coliforms, but some species of Enterococcus are also associated with Plants.

What Indicator Bacteria Should You Test For?

From the above discussion it’s clear that no single indicator organism on it’s own is 100% reliable to demonstrated sewage or fecal contamination. Which bacteria you test for depends on what you want to know.

Do you want to know whether the contaminated surface poses a health risk? If the answer to this question is yes, the best indicators of health risk E. coli and enterococci. Fecal coliforms as a group are a poor indicator of the risk of digestive system illness.

Some experts therefore recommend use of 3 or more indicators, i.e., total coliforms, fecal coliforms, E. coli and/or enterococci.

If you have questions about this articles or our accredited mold and bacteria lab testing service, contact Mold & Bacteria Consulting Laboratories by telephone or email today.