Use Viable Along with Non-Viable Sampling Methods

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When Should Indoor Air Quality Professionals Use Viable Along with

Non-Viable Sampling Methods?

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ATLANTA, GEORGIA, Apr. 25 -/E-Wire/-- Let us begin by defining " Non-

Viable " and " Viable " . Non-viable refers to techniques that identify

fungal spores or conidiophores without any attempt to culture the

spores. It does not infer that the spores are not capable of

germination or growth. Viable techniques are an attempt to recover

either fungal spores or bacterial cells in the environment from

which they were collected. For the purpose of this discussion, non-

viable would refer to the microscopic examination of spore trap,

tape, bulk or swab samples. Viable would include the collection and

growth of fungal spores or bacterial cells on agar air plates, or

dilution plate culturing of fungal or bacterial cells from swab,

bulk or dust samples.

Most IAQ professionals are familiar with the various spore trap

cassettes that are commercially available for the recovery of fungal

spores. These include such names as Air-O-Cell, Cyclex, Micro5, Bi-

Air and BioCell. These are excellent tools to investigate the

current air quality at the beginning of an investigation, during

remediation and post remediation (clearance sampling). However, it

has become, for many investigators, the only microbiological tool

that they employ during an investigation. Although the spore trap is

a powerful tool, it should be complemented with viable sampling in

most situations.

Let us consider what the spore trap can provide for information. The

most useful analysis derived from any spore trap is what types of

fungal spores are present in the environment being sampled. This

includes the outside air, as well as the complaint room (if any),

and other neutral or non-complaint areas in the building. Although

the number of spores/m3 is provided, it is only a relative number.

The type of spores and, even small numbers of " indicator organisms " ,

should be held equally important as the relative number and ranking

produced. An example would be the recovery of small numbers in the

genera Chaetomium, Stachybotrys and Ulocladium. Although these are

not the only indicator organisms, their very presence in the indoor

air individually, or in combination, may be a clue that high water

activity levels exist.

The most numerous spore types typically recovered in the indoor air

are those of the genera Aspergillus and Penicillium. These two

genera have approximately 400 species between them. Unfortunately,

this is where the spore trap reveals its weakness. The vast majority

of reports sent to clients around the world will list these species

lumped together as the genera Aspergillus/Penicillium. I have had

numerous clients over the past 10 years ask the obvious

question; " Can't you tell me which species I have from the spore

trap " ? The answer is " No. " Only viable techniques and DNA-based

technologies can separate out these very important genera and their

related species. In one study conducted in 2003, of over 100,000

identifications from the indoor environment, over 85% were species

from Penicillium and Aspergillus, with most of those coming from the

genus Penicillium.

Now to the core question of " Why do I care what species I have? "

Here the answer is historical as well as practical. Several years

ago, most laboratories were not capable of identifying fungi to

anything but the genus level. This changed when AIHA instituted the

EMPAT testing program in 1996, with its admonition, that all

laboratories should be striving to identify fungi and bacteria

genera to the species level. In addition, classes from Pitt and

Maren Klich have been available for the identification of the

species for both Penicillium and Aspergillus. Thanks, also, to high

profile investigators in this industry, we have also learned that

some species of Aspergillus and Penicillium are more common to the

indoor air. These species can act as indicator organisms, especially

when their numbers increase, relative to other types of genera.

Aspergillus and Penicillium are also noteworthy as many of their

species are known to produce toxins and, therefore, of concern

during an investigation of a complaint area.

A more current reason to identify fungi and bacteria to the species

level involves litigation in this country. At the writing of this

paper, it is reported that over 10,000 cases are in litigation for

indoor air quality complaints. For the IAQ professional this should

be of concern. As anyone who has ever been associated with legal

proceedings recognizes, the side with the most convincing evidence,

and sometimes the most evidence, usually has a better chance of

coming out the winner. Consider: One side presents a count of 200

spores/m3 Aspergillus/Penicillium recovered on a spore trap in the

indoor air, and 250 spores/m3 Aspergillus/Penicillium from the

outside air, and then declares the indoor air " acceptable " . The

other side presents similar information but has also collected air

culture plates on DG18 and reports that the following species were

recovered from the inside air: Aspergillus fumigatus, 75/m3,

Penicillium brevicompactum, 50/m3, Aspergillus versicolor, 50/m3.

The outside air contained Penicillium variabile, 150/m3, Aspergillus

ustus, 100/m3 . This investigator proclaims that the indoor air

is " unacceptable " . Who wins? The second analysis because the

investigator asked for the extra work necessary to demonstrate that

the inside air contained toxic species, such as, A. fumigatus and A.

versicolor, whereas, the outside air did not.

Another industry that should consider requesting speciation is the

insurance industry. An excellent way to determine if a new water

intrusion incident is the same or different than a previous incident

is with speciation. As Aspergillus and Penicillium species will

quite often dominate a water damaged area, especially carpet,

species that dominate and are different from the ones previously

recovered, could indicate a new incident rather than a repeat of a

previous one.

We have only discussed fungi, so far. Most of the industry

concentrates on fungal analysis without investigating the bacterial

species that occur. It is my opinion that one can learn more from

identifying bacterial species along with the identification of

species within Aspergillus and Penicillium. Identification of fungi

can reveal water damage and toxic species. What it can not do is

define the source of the water intrusion. Bacteriologists have been

investigating sources of water intrusion as far back as the early

20th century. Bacteria divide very conveniently into fresh water,

soil, fecal and human associated. Air plates collected in the indoor

air can point to an " acceptable " room with a predominance of

Micrococcus spp., Staphylococcus spp. and Bacillus spp. in low

numbers. Swabs and bulks can also demonstrate the presence of fecal

organisms such as Escherichia coli, which, with the combination of

other coliform organisms would be an indication of a sewage

presence. Another scenario demonstrates that several species of the

genus Pseudomonas spp (fresh water) and Bacillus spp (soil) have

dominated in swab samples obtained from a water-damaged basement.

The indication here would be that the leak may have been from soil

outside of the basement wall, rather than from a sewage pipe break.

There is much more that could be discussed concerning the need for

speciation of fungi and bacteria in the indoor air. I would

recommend discussing these issues with a qualified laboratory that

can provide complete answers to your investigations.

For further information on microbiological laboratory testing

services that EMSL Analytical, Inc. provides, feel free to contact

Rick Billups at EMSL's AIHA EMLAP Accredited Microbiology Laboratory

in Atlanta, GA at 770-956-9150.

About EMSL Analytical, Inc. EMSL Analytical, Inc. currently services

approximately 8,000 clients internationally. They operate 24

laboratories throughout the nation with full analytical services,

including environmental microbiology (mold, bacteria, legionella,

coliforms, indoor allergens, mycotoxins, endotoxins), DNA based

polymerase chain reaction (PCR), asbestos, lead, indoor air quality,

industrial hygiene, environmental chemistry, materials, forensic,

failure, and mechanical testing. EMSL specializes in rapid

turnaround with results in as little as 3 hours. In addition to

laboratory services, the firm provides free industrial hygiene

sampling workshops and free IAQ / Mold sampling workshops at various

locations throughout the United States.

EMSL Analytical currently holds accreditations with the American

Industrial Hygiene Association (AIHA), the AIHA Environmental

Microbiology Laboratory Accreditation Program (EMLAP), the AIHA

Environmental Lead Laboratory Accreditation Program (ELLAP), the

AIHA Industrial Hygiene Laboratory Accreditation Program (IHLAP),

the National Voluntary Laboratory Accreditation Program (NVLAP), the

New York Department of Health (NYDOH), TX DOH, CA E-LAP and various

other state, federal and private accrediting bodies. The labs are

also successful participants in AIHA's Proficiency Analytical

Testing (PAT), Environmental Lead Proficiency Analytical Testing

(ELPAT), and the Environmental Mold Proficiency Analytical Testing

(EMPAT) programs. It maintains a rigorous in-house QA/QC program to

ensure our clients are receiving the most accurate and legally

defensible results possible.

/SOURCE:

EMSL Analytical, Inc.

-0-

04-25-2005

/CONTACT:

Joe Frasca Vice President, Sales & Marketing EMSL Analytical, Inc.

1-800-220-3675 ext 1213

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http://www.EMSLTesting.com