Mold Biology & Identification Flashcards

Which sampling method captures mold spores on a sticky surface as air passes over it at a calibrated flow rate?

Answer: Impaction air sampling

Impaction air sampling (e.g., using RCS or Burkard samplers) draws air at a calibrated rate and impacts spores onto a sticky collection surface for analysis.

What does a high ratio of Aspergillus/Penicillium spores indoors compared to outdoors typically suggest during an investigation?

Answer: An indoor amplification source of mold growth

When indoor Aspergillus/Penicillium counts significantly exceed outdoor levels, it indicates an indoor amplification source such as hidden mold growth.

Which fungal structure allows Rhizopus and Mucor species to be distinguished from other mold genera at the macroscopic level?

Answer: Rapid cottony growth filling culture dishes combined with presence of sporangia

Mucorales (like Rhizopus and Mucor) produce rapid, cottony growth that fills culture dishes quickly and form round sporangia rather than conidia.

The 'Index of Mold Amplification' (IMA) in an indoor environment is best assessed by:

Answer: Comparing indoor spore species and concentrations to simultaneous outdoor samples

The IMA is determined by comparing indoor and outdoor air samples collected simultaneously to identify whether indoor mold counts exceed what would be expected from outdoor infiltration.

Which of the following mold species is an opportunistic pathogen most dangerous to immunocompromised individuals and is commonly found in building HVAC systems?

Answer: Aspergillus fumigatus

Aspergillus fumigatus is a thermotolerant opportunistic pathogen that thrives at body temperature and can cause invasive aspergillosis in immunocompromised patients.

Fungal ergosterol measurement in bulk samples is used in mold investigations primarily to:

Answer: Quantify total fungal biomass regardless of spore viability

Ergosterol is a sterol found in fungal cell membranes; its concentration in bulk samples provides an estimate of total fungal biomass including non-sporulating and dead fungi.

What is the primary reason mold species identification by cultural (viable) analysis may take 7–14 days compared to direct microscopy?

Answer: Spores must germinate and colonies must mature sufficiently to display identifying structures

Cultural analysis requires spores to germinate and grow into mature colonies displaying characteristic reproductive structures before accurate genus and species identification is possible.