DNA Forensic Mold Detection

[Guest guest]

DNA Forensic Mold Detection

Main Category: Respiratory / Asthma News

Article Date: 22 Apr 2007 - 7:00 PDT

http://www.medicalnewstoday.com/medicalnews.php?

newsid=68548 & nfid=rssfeeds

Medical News Today Sun, 22 Apr 2007 8:14 AM PDT

Extensive research conducted by the US EPA, using State-of-the-Art

DNA forensics, has established the Environmental Relative Moldiness

Index, otherwise known by the acronym ERMI. The ERMI study narrowed

down the total number of critical mold species to 36 indoor-

indicator mold species. Furthermore, the 36 species were subdivided

into two very different groups of mold (fungal) species; these

included the Group 1 and Group 2 molds. The Group 2 molds were found

to be common in most homes and in low concentrations. Occupants

living and working in indoor environments that contained

predominantly Group 2 molds were healthy and suffered few

respiratory related illnesses, nor did the building structures

suffer leaks and water intrusion.

However, Group 1 molds were much less benign, and occupants of these

homes and environments suffered significant respiratory and asthma

related illnesses. Moreover, Group 1 molds were significantly

correlated to water intrusion due to poor construction or leaking

pipes. Furthermore, EPA scientist and other reputable scientific

investigators have amassed a body of published scientific research

that conveys a major paradigm shift in the way mold samples are both

collected and analyzed.

Currently 99% of all mold samples are collected from the air.

Inspectors pump air, often for as little as 5 minutes, onto a sticky

device called a spore-trap (not unlike flypaper). They send the

spore trap to a lab for analysis, and the lab spits back a report,

based on the shape and size of the spores they see. It is important

to keep in mind, that a mold cannot be identified as belonging to a

particular species using a spore trap analysis, regardless of how

much training or how many degrees a spore trap analyst has.

Unfortunately, many of the group 1 and group 2 mold spores are small

and round and all get lumped into a common small-round spore trap

grouping called Asp/Pen. Hence, neither an ERMI score nor any

substantial conclusion can be drawn from spore trap analysis.

The EPA solved this problem by using good science to make major

breakthroughs in both mold sampling and analysis.

First, the EPA identified the best technology, to date, to identify

mold. That technology is called quantitative PCR or qPCR for short.

Quantitative PCR is used in many fields of science, such as genetics

and cancer research. The qPCR technology directly probes the DNA of

mold with 99.9% accuracy to detect which species of mold are present

and how many spores of each species are contaminating the indoor

environment.

Secondly, the EPA used qPCR to probe the DNA of molds from the

various reservoirs in homes. Surprisingly, they found air to be a

poor correlate for detecting group 1 mold contamination (the water

intrusion/asthma molds). So they looked elsewhere, and found that

every indoor environment harbors a stable mold reservoir; that

reservoir was dust.

Moreover, the dust held an historical account of indoor mold. Hence,

indoor dust has a historical moldy tale to tell, which is read from

mold DNA. Sometimes that tale is the sorrowful account of leaky

roofs, windows or pipes (the DNA identifies many group 1 mold

species), other times it is a story of a happy dry home (common

group 2 mold species).

All buildings have dust and by analyzing the DNA in that dust for

mold, all skeletons come out of the closet. And those skeletons,

whether good or bad, are reflected in the EPA's ERMI index. The ERMI

index is just a score based on the amounts of group 1 (water

intrusion) versus group 2 molds (common).

The ERMI score from DNA analysis of dust lets a building or home

owner know whether their home has group 2 molds and is similar to

the rest of the healthy homes identified in the EPA studies, or if

it is infested by group 1 mold species, where water intrusion and

respiratory problems are common.

By: A. Sobek, Ph.D.

Published Scientific Literature

-- Mannino DM, Homa DM, Akinbami LJ, et al. Surveillance for asthma-

United States, 1980-1999. MMWR Morb Mortal Wkly Rep. 2002;51:1-13.

-- on IJ, CJ, McGill G, et al. Damp housing and

asthma: a case-control study. Thorax. 1997;52:229-234.

-- Belanger K, Beckett W, Triche E, et al. Symptoms of wheeze and

persistent cough in the first year of life: associations with indoor

allergens, air contaminants and maternal history of asthma. Am J

Epidemiol. 2003;158:195-202.

-- Dales RE, , D. Residential fungal contamination and health:

microbial cohabitants as covariates. Environ Health Perspect.

1999;107:481-483.

-- Institute of Medicine, National Academies of Science. Damp Indoor

Spaces and Health. The National Academies Press; 2004:355.

-- Vesper SJ, Varma M, Wymer LJ, et al. Quantitative polymerase

chain reaction analysis of fungi in dust from homes of infants who

developed idiopathic pulmonary hemorrhaging. J Occup Environ Med.

2004;46:596-601.

-- Dearborn DG, Kercsmar CW, Schluctler MD, et al. Home

interventions regarding mold and moisture and the impact on the

respiratory health of children. Annual Meeting Inter Soc Exposure

Assessment; Philadelphia; October 2004.

-- Haugland RA, Brinkman NE, Vesper SJ. Evaluation of rapid DNA

extraction methods for the quantitative detection of fungal cells

using real time PCR analysis. J Microbiol Methods. 2002;50:319-323.

-- Brinkman NE, Haugland RA, Wymer LJ, et al. Evaluation of a rapid,

quantitative realtime PCR method for cellular enumeration of

pathogenic Candida species in water. Appl Environ Microbiol.

2003;69:1775-1782.

-- Haugland RA, Varma M, Wymer LJ, et al. Quantitative PCR of

selected Aspergillus, Penicillium and Paecilomyces species. Syst

Appl Microbiol. 2004;27:198-210.

-- Helsel DR. Nondetects and Data Analysis, Statistics for Censored

Environmental Data. Hoboken, NJ: Wiley and Sons Inc; 2005.

-- Meklin T, Haugland RA, Reponen T, et al. Quantitative PCR

analysis of house dust can reveal abnormal mold conditions. J

Environ Monit. 2004;6:615-620.

-- O'Connor GT, Walter M, H, et al. Airborne fungi in the

homes of children with asthma in low-income urban communities: the

Inner-City Asthma Study. J Allergy Clin Immunol. 2004;114:599-606.

-- Nevalainene A, Seuri M. Of microbes and men. Indoor Air.

2005;9:58-64.

-- Kurup VP, Fink JN. Fungal allergen. In: JW, Friedman H,

Bendinelli M, eds. New York: Plenum Press; 1993:393-404.

-- Chung Y, Coates NH, Viana ME, et al. Dose-dependent allergic

responses to an extract of Penicillium chrysogenum in BALB/c mice.

Toxicology. 2005;209:77-89.

-- Gergen PJ, Mortimer KM, Eggleston PA, et al. Results of the

National ative Inner City Asthma Study (NCICAS) environmental

intervention to reduce cockroach allergen exposure in inner city

homes. J Allergy Clin Immunol. 1999;103:501-506.

-- Flannigan B, JD. Microbial growth in indoor environments.

In: Flannigan B,

-- Samson RA, JD, eds. Microorganisms in Home and Indoor Work

Environments. London: and Francis; 2001:35-67.