Fungi Overview

What is Fungi?

Fungi on CeilingFungus, plural fungi, any of about 99,000 known species of organisms of the fifth kingdom, Fungi, which includes the yeasts, rusts, smuts, mildews, molds, and mushrooms. There are also many funguslike organisms, including slime molds and oomycetes (water molds), that do not belong to kingdom Fungi but are often called fungi. Many of these funguslike organisms are included in the kingdom Chromista. Fungi are among the most widely distributed organisms on Earth and are of great environmental and medical importance. Many fungi are free-living in soil or water; others form parasitic or symbiotic relationships with plants or animals.

Fungi are eukaryotic organisms; i.e., their cells contain membrane-bound organelles and clearly defined nuclei. Historically, fungi were included in the plant kingdom; however, because fungi lack chlorophyll and are distinguished by unique structural and physiological features (i.e., components of the cell wall and cell membrane), they have been separated from plants. In addition, fungi are clearly distinguished from all other living organisms, including animals, by their principal modes of vegetative growth and nutrient intake. Fungi grow from the tips of the filaments (hyphae), in mass they are called (mycelia), and they digest organic matter externally before absorbing it into their mycelia.

While mushrooms and toadstools (poisonous mushrooms) are by no means the most numerous or economically significant fungi, they are the most easily recognized. The Latin word for mushroom, fungus (plural fungi), has come to stand for the whole group. Similarly, the study of fungi is known as mycology—a broad application of the Greek word for mushroom, mykes. Fungi other than mushrooms are sometimes collectively called molds, although this term is better restricted to filamentous molds, the types represented by bread mold.

Importance of Fungi

Fungi are everywhere in very large numbers—in the soil and the air, in lakes, rivers, and seas, on and within plants and animals, in food and clothing, and in the human body. Together with bacteria, fungi are responsible for breaking down organic matter and releasing carbon, oxygen, nitrogen, and phosphorus into the soil and the atmosphere. Fungi are essential to many household and industrial processes, notably the making of bread, wine, beer, and certain cheeses. Fungi are also used as food; for example, some mushrooms, morels, and truffles are epicurean delicacies, and mycoproteins (fungal proteins), derived from the mycelia of certain species of fungi, are used to make foods that are high in protein.

  • It is a eukaryotic organism (its cells have nuclei containing chromosomes)
  • It is heterotrophic (it has no plastids, so can’t photosynthesize to make its own food)
  • It is osmotrophic (it absorbs, doesn’t ingest, food)
  • It reproduces by means of spores or conidia (microscopic seed-like structures)
  • It develops a rather diffuse, branched, tubular body called a mycelium or colony
  • Fungi are in a kingdom of their own. They are neither plants nor animals
  • Most fungi are saprophytic. A saprophyte is an organism that derives food from dead organisms or from organic substances liberated by living ones
  • Fungi are also important plant and animal pathogens and occupy many other niches in the ecosystem
  • Their life cycles can be very complex and often involve both a sexual and an asexual stage
  • All molds are fungi but not all fungi are molds
  • Molds are also called microfungi because the sporulating structures are microscopic

The true fungi (Eumycota) include:

  • Mushrooms
  • Toadstools
  • Cup fungi
  • Morels
  • Bracket fungi
  • Puffballs
  • Earthstars
  • Truffles
  • Yeasts
  • Moulds
  • Lichens
  • Athlete’s foot organism
  • Black spot of roses
  • Many more…

A fungus usually starts life as a spore:

They may travel a long way through the air or water. If it is lucky it will land where there is food and water, which will allow it to germinate and develop hyphae. Hyphae are tubular and usually about 5 microns wide.

They grow only at the tip. They also branch, soon forming a colony.

Mold (Fungi)


Molds are fungi that are found everywhere – both indoors and outdoors all year round. The terms fungi and mold are often used interchangeably, but mold is actually a type of fungi. Concern about indoor exposure to mold has increased along with public awareness that exposure to mold can cause a variety of adverse health effects. There are many thousands of species of mold and most if not all of the mold found indoors comes from outdoor sources. It seems likely to grow and become a problem only when there is water damage, high humidity, or dampness.

Molds produce and release millions of spores small enough to be air-, water-, or insect-borne. They can also produce toxic agents known as mycotoxins. Spores and mycotoxins can have negative effects on human health. For those people who are affected by mold exposures there can be a wide variation in how they react. People at greatest risk of health effects are individuals with allergies, asthma, sinusitis, or other respiratory conditions, as well as infants and children, elderly people, and pregnant women. In addition, individuals with a weakened immune system are at risk.

  • originates from the outdoor environment
  • outside counts typically higher than indoors
  • spores very small (about 1 micron)
  • about 250,000 can fit on the head of a pin
  • over 100,000 types of mold
  • about 1,000 found in US
  • 15-20 types associated with health effects

What Do Fungi/Mold need to survive?

  • A Food Source
  • Moisture
  • The Proper Temperature Range
  • Oxygen

Fungi/Molds Indoors/What’s the Big Deal?

  • Production of vast numbers of allergenic spores. Susceptible individuals will react to these spores and can cause asthma and/or hay fever symptoms.
  • Fungi produce Microbial Volatile Organic Compounds known as (MVOC’s).
  • Fungi produce mycotoxins. Some like Aflatoxins are among the most toxic substances known.
  • Fungi can cause undesirable changes on the substrates it is breaking down. This is called the biodeteriogenic effect and many molds are considered biodeteriogens.
  • It just isn’t healthy to live or work in a moldy environment.
To learn more about mold testing and our related services please request information using the form here or call us at (877) 648-9150. Thank you!

Health Effects:

  • Allergenic
  • Infectious
  • Toxic

Health Effects Attributed to Mold Exposure:

  • potential for both allergenic and toxigenic health effects, depends on mold type
  • symptoms include headaches, nasal congestion or discharge, nose-bleeds, asthma, sneezing, rashes, watery or itchy eyes, bone and muscle pain, sore throats, fever, diarrhea, episodic vertigo, shortness of breath
  • Symptoms often improve when away from indoor space or after remediation
  • Mold can be pathogenic to those who are susceptible such as immuno-compromised patients

Conditions Related to Biological Agents:

  • Histoplasmosis – Fungi
  • Coccidioidomycosis – (Valley Fever)
  • Humidifier Fever – Bacteria/Amebae/Endotoxin
  • Hypersensitivity Disease – Allergy
    • Bacterial Antigen
    • Fungal Allergen
    • Arthropod Allergen
  • Hypersensitivity Pneumonitis (HP)
    • Bacterial Antigen
    • Bacterial Proteases
    • Fungal Allergens
  • Infectious Diseases
    • Cryptococcus, Histoplasmosis, Legionnaire’s Disease
  • Inhalation Fever
    • Bacteria, Legionella, fungi, amoeba, endotoxin
  • Organic Dust Toxic Syndrome (ODTS)
    • High organic dust levels

Pathogenic Fungi & Opportunistic Fungi Mycoses

In true pathogenic fungus infections, the fungus is virulent regardless of the constitutional adequacy of the host. True pathogenic fungi include Histoplasma, Coccidioides, Blastomyces, and Paracoccidiodies.

  • Pathogenicity is an accidental phenomenon and is not essential to the survival or dissemination of the species involved. Most infections are either completely asympotmatic or of very short duration and quickly resolved. Resolution of the infection is accompanied by a strong specific resistance to reinfection that is of long duration.
  • Very restricted geographic distribution of fungus
  • Sex, age, and race are important factors in the statistics of pathogenic fungus infections
  • Pathogenic fungi exhibit a morphological transition from a the mycelial or saprobic form to the parasitic form found in infected tissue. Thermal dimorphism is common!

BLASTOMYCOSIS (Chicago disease; North American Blastomycosis)

  • chronic granulomatous and suppurative (bleeding pus) disease having a primary pulmonary stage that is frequently followed by dissemination to other body sites (e.g., skin and bone).
  • Occurs in humans and dogs (also seen in horses, wild animals, northern sea lion).
  • Anamorph, asexual, or imperfect form of fungus, Blastomyces dermatitidis is the etiological agent (perfect form of this fungus is Ajellomyces dermatitidis, an ascomycete).
  • Dimorphic or diphasic fungus (converts from filamentous form to yeast form and vice versa)
  • Soil saprophyte (erratic distribution, grows on decaying organic materials).
  • Some evidence for presence of disease in Middle Eastern countries, Africa, India, South America.
  • Discovered in 1890’s by Caspar Gilchrist
  • Diseases acquired through inhalation of conidia
  • Primary cutaneous disease is rare.
  • Very rare are reported cases of infection by yeast phase through (a) sexual transmission (from man to woman), (b) person-to-person, or (c) animal to person contact.
  • Chronic pulmonary and disseminated disease if left untreated is fatal
  • Infection more likely in middle-aged men (rapid dissemination can occur in women during pregnancy).
  • Median incubation period is 45 days following exposure to symptoms.

Hygienist/Laboratory Coordination:

bacteria testing lab

  • Contact lab before sampling event
  • Discuss
  • Proactive vs Reactive
  • Setting: commercial vs residential vs hospital
  • Occupants
  • Building history
  • Equipment needed for sampling
  • Sampling media
  • Turn Around Time (TAT)


  • Calibration of equipment
  • Maintain supplies: plates, swabs, slides
  • Understand your media needs
  • What products to use, why and when
  • Aggressive vs. passive sampling
  • Expiration dates
  • Storage
  • Culture plate temperature
  • Culture agars (bacterial/fungal)

Packaging and Transportation:

  • Coordinate delivery with Laboratory
  • Samples must be packaged individually
  • Use cooler provided by Laboratory
  • Package with Care….No Loose Contents
  • Overnight transportation
  • First am – 8:00am
  • Routine am – 10:30am
  • Routine pm – 2:00pm

Chain of Custody provides the following information:

  • Date collected
  • Type and number of samples submitted
  • Test code/matrix
  • Location
  • Total air volume/area

Options for Mold Sample Analysis:

Two basic type of analysis available:

  • Viable or Culturable
  • Non-Viable or Non-Culturable or Direct
Viable vs Non-Viable
Detects viable Fungi Detects non-viable & viable
Incubation time (5-7 days) Allows for rapid TAT
Allows for genus/speciation Report to Genus level and groupings

Mold Sampling Equipment

What do I use? First question should be, what is my purpose in sampling?

  • Measure Viable (Culturable) Organisms
  • Measure Non-Viable (Total Fungal)

Measure Viable/Culturable Organisms

  • Impactor Style (Andersen, SAS, Microflow)
  • Surface (swab, sponge, contact plate)
  • Bulk Building Material
  • Composite Dust
  • Water
    • Condensate pans
    • Cooling towers
    • Humidification systems
    • Fire sprinkler systems

Measure Non-Viable Total Fungal Spores (Air)

  • AeroTrap – slide impactor
  • Burkard – slide impactor
  • BioAire – cassette
  • Cassette Types (Air-O-Cell, Allergenco D, Micro 5)

Measure Non-Viable Total Fungal Spores (Surface)

  • Direct Swab
  • Direct Tape –Mold Tape Slide – EMS, Bio Tape-Zefon
  • Direct Vacuum Sample – MCE, PCM

Fungi Services (please contact your Account Manager for pricing)

basidiomycete culture plate - bacteria and fungi testing

  • AIR (Aerotrap, Allergenco D, Air-O-Cell™, Micro5, etc.)
  • Spore Trap Analysis* Test Code 1054
  • Spore Trap Analysis* w/ non-biological particle characterization Test Code 2080
  • Non-biological Particle Characterization* Test Code 1026
  • *Background debris, pollen, insect parts and skin cells noted if identified


  • Qualitative Direct Microscopic Exam* Test Code 1051
  • Quantitative Direct Microscopic Exam* (Tape Only) Test Code 1049
  • *Background debris, pollen, insect parts and skin cells noted if identified

BULK / DUST (Dust, Building Material)

  • Qualitative Direct Microscopic Exam* Test Code 1050
  • Quantitative Direct Microscopic Exam* Test Code 6000
  • Wood Decay Analysis (Serpula species, phellinus species) Contact Lab
  • *Background debris, pollen, insect parts and skin cells noted if identified


  • Qualitative Direct Microscopic Exam Test Code 1052


Fungal Analysis (Please Submit Ice Packs with Samples)


  • Fungal Count w/ Complete Genus Identification* Test Code 1030
  • Stachybotrys species & Fungal Count w/ Full Genus ID* 1038
  • Cryptococcus specs. & Fungal Count w/ Full Genus ID* Test Code 1098
  • Thermophilic Fungal Count w/ Full Genus ID* Test Code 1059
  • Air Culture Full Fungal Speciation Test Code 1127
  • *Speciation of Aspergillus included in full genus ID


  • Fungal Count w/ Complete Genus ID* Test Code 1031
  • Stachybotrys & Fungal Count w/ Full Genus ID* Test Code 1037
  • Cryptococcus & Fungal Count w/ Full Genus ID* Test Code 1097
  • Thermophilic Fungal Count w/ Full Genus ID* Test Code 1057
  • Surface/Wipe Culture Full Fungal Speciation Test Code 1117
  • *Speciation of Aspergillus included in full genus ID


  • Fungal Count w/ Complete Genus ID* Test Code 1033
  • Stachybotrys & Fungal Count w/ Full Genus ID* Test Code 1035
  • Cryptococcus & Fungal Count w/ Full Genus ID* Test Code 1099
  • Thermophilic Fungal Count w/ Full Genus ID* Test Code 1058
  • Bulk/Dust Culture Full Fungal Speciation Test Code 1119
  • *Speciation of Aspergillus included in full genus ID


  • Fungal Count w/ Complete Genus ID* Test Code1032
  • Water Culture Full Fungal Speciation Test Code 1129
  • *Speciation of Aspergillus included in full genus ID

TARGET FUNGI ANALYSIS (please contact your Account Manager for pricing)

  • Fungal Organism Speciation (One ID) Test Code 2001
  • Aspergillus fumigatus Test Code 1143
  • Cryptococcus neoformans Test Code 1098
  • Penicillium species Test Code 1100
  • Aspergillus species Test Code 1101
  • Candida albicans Test Code 1145
  • Candida species Test Code 1146
  • Stachybotrys chartarum Test Code 1147
  • Fusarium species Test Code 1148
  • Acremonium species Test Code 1149
To learn more about mold testing and our related services please request information using the form here or call us at (877) 648-9150. Thank you!