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Molds, spores, fungi and yeast

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Section A: The biological agents like molds and bacterias

Image of molds in a Petri dish from indoor air quality sampling

Biological agents are substances that come from living things or are living beings capable of causing adverse effects or disease on biological organisms like humans. Microorganisms are living organisms imperceptible to the naked eye. The microorganisms that cause disease are called pathogens. Other micro-organisms, called opportunistic organisms , become pathogenic under certain specific conditions circumstances. To survive, microorganisms need sources of moisture and food. The main sources of moisture in buildings are typically found in the vicinity of windows where there is condensation in the ducts of poorly insulated ventilation in places where there was water infiltration , etc.


Often pathogens produce toxins that can cause problems in people who live in infested areas. Many of these toxins cause symptoms of various diseases of the microorganism itself. Toxins are chemicals secreted by fungi (mycotoxins ) and bacteria ( endotoxins ) . The health risks are also connected to the presence of other microorganisms that live and multiply easily in a wet environment such as dust mites and bacteria.

MOLD , MOLD SPORES , FUNGI AND YEASTS


The kingdom of fungi is composed of diverse organizations and is available in two forms: macroscopic ( visible with the naked eye ) and microscopic ( invisible to the naked eye).

Molds are visible to the naked eye when they entangle to form colonies . The appearance of colonies can be very diverse ; it can be cottony , velvety or granular ; colors white, black , green or blue , etc.

The colonies are pervasive in all environmental media and actively participate in recycling organic material by degrading plant materials.

All fungal particles are likely to cause other adverse effects on health, according to their nature and quantity, depending on the degree of exposure, and depending on the sensitivity of people exposed . The term Mold is a common name to designate microscopic fungi that form on food and building materials . They multiply by issuing spores into the air . Spores, the diameter of which is about five (5) microns, are particularly harmful , because , when present in the ambient air, they may be inhaled and deposited subsequently , in the alveoli ; which can cause respiratory problems.

The fungi can cause disease in several ways: by mycotoxins and allergens they produce, and biologically active components of their cell wall that can cause serious signs of discomfort to the occupants. These effects are mainly about respiratory (irritation and allergies) and immunological . These toxic effects are due to various substances produced by fungi : the propagules or spores for reproduction of the fungus , mycotoxins or chemicals associated with spores or vapors detected their musty odor.

A report of the working group on fungi in the air of homes Health Canada and two recent Canadian studies have clearly demonstrated that the high humidity and the presence of fungi ( molds) and their toxins can cause the following health problems in humans :


  • Respiratory symptoms : cough, sputum, irritation of the nose and throat , runny nose, sneezing , noisy breathing difficulty breathing, chest pain ;
  • Respiratory allergies : rhinitis, alveolitis , bronchitis, asthma, hypersensitivity pneumonia ;
  • Non-respiratory symptoms: eye irritation, lesions and tissue infections, skin allergies ( skin irritation , dermatitis) ;
  • General toxic effects : fever, chills , headache , nausea, vomiting , diarrhea, immune system deficiencies , fatigue, hair loss.

MOLD AND MOISTURE

Moisture is one of the most common causes of poor air quality in offices, in homes, in classrooms and in public indoor spaces , because it promotes the growth of mold and mites. Mould can grow in damp or wet areas of a building , and that , due to a water leak , flood , infiltration or high humidity due to activities human . They can appear on wood , paper , fabric , drywall and insulation . They can hide inside the walls and above the ceiling tiles. If the molds grow in damp , they can cause a deterioration of air quality and health issues .

Exposure to moisture and mold in homes is an important risk factor that can cause respiratory diseases. Specifically, it is estimated that 40% of Canadian homes could present moisture and mold signs. Molds are microscopic fungi whose growth is favored by high humidity, the presence of stagnant water and inadequate ventilation. When they grow significantly, mold disperse respirable particles that can cause, especially among children, health problems: irritation of eyes, nose and throat, nasal congestion and discharge, and increased frequency and severity of asthma attacks. Emphasize that it remains difficult to directly associate the symptoms experienced by the occupants of a building to a fungal profile revealed by laboratory analysis results. To this end, it is better to have the advice of a doctor. Moreover, these results can not be used alone to declare a low quality of indoor air. They must be combined with in situ observations and their interpretation depends on the accuracy of the analyzes. However, no fungal contamination or any water accumulation favoring should not be tolerated in indoor environment. In interior areas, the main element determining the fungal growth is water and its corollary, moisture (infiltration, condensation, damp climate indoor planting, etc.). Without them, there is no possibility of mold growth. The activity resulting from the presence of water (and moisture) is the most important element to be monitored to prevent contamination.


SAMPLING AND ANALYSIS OF BIOLOGICAL CONTAMINANTS ( MOLD )

The analyzes carried out in laboratories are accredited by the Ministry of Sustainable Development , Environment and the Fight against Climate Change ( MDDELCC ) in Quebec. All collected samples are analyzed in a laboratory and approved by specialized microbiology microbiologists . Laboratory technicians are certified by the Canada Mortgage and Housing Canada (CMHC). All laboratory operations are carried out according to international standard ISO / IEC 17025. All sampling methods comply with the standards and regulations of the Health Research Institute and safety of Quebec ( IRSST) and Regulation health and safety of Health Canada. The AES Environment sampling technicians are continuously trained according to the protocols specified by the lab .

Depending on the specific needs of each situation and depending on the time available to achieve the results provided by the laboratory , here are the different methods of sampling used by AES in the search for domestic environmental contaminants :


METHOD 1 ) COLLECTION OF MOLD IN AIR BY SPORE TRAPS

The microbiological surveys of total mold spores in the air are made ​​with Spore Trap . The parameters obtained from these samples are the total count of mold in the air and mold genera identification .

In order to establish this type of microbiological air statement , mold spores total ( viable and non-viable) should be sampled in order to get an accurate count of total fungal particles in the air . To do this, the air samples are collected using a pump and a Allergenco -D / EMS type of cassette. This type of trap spore sampler pump 75 liters of surrounding air through the cassette , and this for 5 minutes. ( or 150 liters during 10 minutes) This cassette is provided with a microscope slide coated with an adhesive film on which the particles in the bleed air are impacted . Sampling techniques apply to spores viable and non- viable mold ( total amount of spores) .


METHOD 2 ) COLLECTION OF MOLD IN AIR BY BIO IMPACTION ANDERSEN

Microbiological surveys of mold fungi - yeast in the air achieved by bio- impaction Andersen. The parameters obtained from these samples are numbered, identifying the genera and species . Only viable mold in the air are identified with this method , that is to say, it does not detect dead mold may nevertheless remained allergens.

The microbiological air samples are collected using an Andersen impactor. With the method of impaction, air enters the apparatus through the top of the unit, and the microorganisms are separated and stored in a suitable culture medium by centrifugal force. The culture medium used for mold and yeast is YM (Rose Bengal Agar). The samples are stored at 4 ° C. until they are returned to the laboratory where they are incubated for several days. The results of laboratory analyzes are given in CFU / m3 (colony forming unit / cubic meter of air). Data interpretation is done by comparing the volumetric results between indoor and outdoor air; Moreover, one should find in both types of air, a similar distribution of mold types, but a concentration of lower mold in the air inside. These techniques apply to only viable mold. The research by bio-impaction are very useful when it comes to depth investigations; because this technique requires a laboratory waiting period corresponding to the incubation time of transplanting and re incubation living material (agar cultures). Extensive environmental research are being developed submissions and custom-built, case by case.


METHOD 3 ) COLLECTION OF MOULD ON SURFACES BY SMEAR

A surface contaminant sample for microbiological analyzes is removed with a cotton swab specially designed for the collection and transportation of microorganisms. This sampling method is defined as the " smear -Contact ". For example, an area of ​​100 cm2 ( 10cmx10cm ) is sampled with a swab to obtain the results as CFU / 100 cm2. Sampling applies to viable mold only , however it should be noted that these results do not reflect the quality of indoor air. These levies are generally made ​​within the ducts or the air vents and any other suspicious appearance surfaces. The parameters obtained are the enumeration of mold on surface , identifying the kind of the mold surface and the identification of the species of mold surface.


METHOD 4 ) COLLECTION OF MOULD ON BONDING SURFACES

The samples are made ​​using self-adhesive strip ( tape lift ) affixed against mold , this method is usually used to establish a partial identification identify mold. However, the results do not reflect the quality of indoor air.

BACTERIA

Bacteria are microscopic living cells with a relatively simple structure ; they are unicellular . Bacterial infections are contracted through respiratory and digestive tract or during inoculation by bite , by scratching, by scratching and cutting.


Bacteria in the ambient air from two sources : aerosol generated by water as humidifiers, faucets, showers, etc. , and aerosols generated by humans or by animals.


The spoilage and pathogenic bacteria are released into the air by people when they sneeze, cough and speak . These bacteria can survive for varying periods of time whose duration is a function of the size of the droplets projected , the temperature of the air, the relative humidity and the presence of a substrate which allows it to travel.


It is usually accepted that the transmission of diseases from person to person can be done by an aerosol exposure, but few people know that bacteria carried by water, which are present in the environment , can multiply . These bacteria can be concealed inside the buildings and cause disease . Some types of bacteria are found in humidifiers ventilation systems. They then cause the syndrome called " humidifier fever ". This syndrome is a response to allergens carried by the air which include endotoxins of a number of Gram-negative bacteria . Endotoxins can cause fever , leukocytosis or leukopenia (decreased white cell count ) in humans . In addition , exposure of the skin to certain bacteria can cause dermatitis (a skin disease ) , etc.

Image of baterias in a Petri dish from indoor air quality sampling

SAMPLING AND ANALYSIS OF BIOLOGICAL CONTAMINANTS ( BACTERIA )

The analyzes carried out in laboratories are accredited by the Ministry of Sustainable Development , Environment and the Fight against Climate Change ( MDDELCC ) in Quebec. All collected samples are analyzed in a laboratory and approved by specialized microbiology microbiologists . Laboratory technicians are certified by the Canada Mortgage and Housing Canada (CMHC). All laboratory operations are carried out according to international standard ISO / IEC 17025. All sampling methods comply with the standards and regulations of the Health Research Institute and safety of Quebec ( IRSST) and Regulation health and safety of Health Canada. The AES Environment sampling technicians are continuously trained according to the protocols specified by the lab .

Depending on the specific needs of each situation and depending on the time available to achieve the results provided by the laboratory , here are the different methods of sampling used by AES in the search for domestic environmental contaminants :

Depending on the specific needs of each situation and depending on the time available to achieve the results provided by the laboratory , here are the different methods of sampling used by AES in search of domestic environmental contaminants :


METHOD 1 ) COLLECTION OF BACTERIA IN AIR BY BIO IMPACTION ANDERSEN

Airborne bacteria in the air, the parameters obtained from these samples are numbered, Gram staining and identification of the species. Bacteria, microbiological air surveys are realized on samples using an Andersen impactor. With the method of impaction, air enters the apparatus through the top of the unit and the microorganisms are separated and stored in suitable culture media by the force of impaction. For bacteria, the culture medium used was Agar Yellow / penicillin. The samples are stored at 4˚C. The results of laboratory analyzes are given in CFU / m3 (colony forming unit / cubic meter of air). Data interpretation is done by comparing the volumetric results between indoor and outdoor air. The concentration of bacteria should be lower inside than outside. Sampling techniques apply only to viable bacteria.

AES Environment adopted a default that research protocol is a combination of enumeration and classification Gram stain . A priori , the count will indicate if the evaluated area is contaminated or not, Gram stain will indicate whether the family of bacteria belongs either to the family of Gram + and Gram - .

Example of bacteria of the family of Gram (+) such as Staphylococcus, Streptococcus , Enterococcus ...

Example of bacteria of the family of Gram (-) such as Escherichia coli , Enterobacter , Salmonella ...

If it is relevant in the investigation process , will be chosen for further research to identify the species 2-3 dominant colonies which were cultured on agar which will have been previously incubated .


Air - Bacteria ( BHAA )

Our basic research protocol will include the following steps:

  • Counting BHAA (Gram negative) type of MacConkey agar
  • Counting BHAA on Agar type TSA 100
  • Classification by Gram stain


Our advanced search option protocol include this additional step :

  • Identification of 2-3 dominant bacterial species in culture medium


METHOD 2 ) COLLECTION OF BACTERIA ON SURFACE ARRAY AGAR ( SWAB )

Viable bacteria surface - the parameters which can be obtained by these samples are numbered, Gram stain and identification to species . A sample of surface contaminants for microbiological analyzes is taken using a swab specially designed for the collection and transport of microorganisms . This sampling method is defined under the name of the term '' smear -Contact ' . An area of ​​100 cm2 ( 10cmx10cm ) or 25 cm2 ( 5cmx5cm ) according to the situation will be sampled with a swab to obtain the results as CFU / cm2. Sampling applies to viable bacteria only. These samples are normally carried out inside the ducts or the ventilation grilles and all other suspicious appearance surfaces.

The count is the basic step , it will indicate whether the evaluated area is contaminated or not, without more. Gram staining , the following search step , it will indicate the family of bacteria belonging either Gram + or Gram . Often a customer will choose to further research of this type for 2 or 3 dominant colonies in the same sampling area .

Example of bacteria family Gram (+ ) as Staphylococcus , Streptococcus , Enterococcus ...

Example of bacteria of the family of Gram (-) such as Escherichia coli , Enterobacter , Salmonella ... .

The third and final research step is to take 2 or 3 colonies that were selected during the selection for Gram stain and make the identification. The advantage of identification lies mainly in the knowledge that the strain will choose a biocidal product specifically appropriate to eradicate it.

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