The identification of bacteria and fungi isolated from controlled environments ranging from Class 100,000 to sterility suits of Class 100 or less is accomplished biochemically by methods briefly set forth in USP and in greater detail by other methods. Identifications are important for seven reasons:

1. Detection of pathogenic organisms that can put the patient or consumer at risk including anthrax spores, methicillin resistant Staphylococcus aureus (MRSA), and toxigenic E. coli.
2. Detection of common environmental or spoilage organisms that can put the product at risk.
3. Detection of the source of the organisms as to raw materials, water, or personnel.
4. Determination of the effectiveness as to the appropriate choice of chemical germicides.
5. General adherence to cGMP.
6. Preparation of trend analysis so as to establish alert and action limits.
7. Identification of organisms that the FDA can site as adulteration or misbranding.

 

Identification analysis will show that gram positive bacteria (e.g., Bacillus, Micrococcus) are more common on dry surfaces than gram negative bacteria. Gram negative bacteria (e.g., E. coli, Pseudomonas, Klebsiella, Enterobacter), are more common in water, soil, and products of natural origin. Fungi disseminate through the air from soil and vegetation and then thrive where there is moisture, warmth, and still air. Viruses are not included in environmental practice. The presence of Staphylococcus aureus and diphtheroids might suggest transmission from humans.

With regard to fungi, the genera Penicillium and Aspergillus are the most common. There are many other groups. Product adulteration rather than pathogenicity is the main problem with fungi, with the exception that inhalation of the spores of Aspergillus fumigatus can cause illness. The term “fungus” is a broad term and encompasses organisms known as yeasts (highly vegetative and human skin-associated) and those described as filamentous fungi or molds. The isolation of filamentous fungi in a controlled area is a serious problem and presages a severe breakdown in barrier and disinfection functions.

From: “Detection of Microorganisms and Particulates in Controlled Environments”