The first step for correct bacterial identification, especially concerning a clean room isolate, is the Gram staining, since it can provide elucidative clues about the source of the microbial contamination. If microbial identification of isolates reveals Gram-positive cocci, the source of contamination can be derived from humans. If bacteria identification of isolates reveals Gram-positive rods, the source of contamination can be derived from dust or strains resistant to disinfectants. If bacterial identification of isolates reveals Gram-negative rods, the source of contamination can be derived from water or any moistened surface.
Microbial identification in pharmaceutical clean rooms is required for several reasons associated with quality assurance: determination of organisms from the manufacturing environment; bacteria identification from final product testing; demonstrating absence of named organisms from non-sterile products and water; quality control of fermentation stocks in biotechnology; and confirmation of test organisms in validation processes. More and more, the Food and Drug Administration (FDA) is expecting bacterial identification to aid in determining the usual flora for a specific site, to evaluate the effectiveness of cleaning and to troubleshoot the source of contamination that can occur when action levels are exceeded or sterility tests become contaminated.