The characterization of microbes, such as opportunists and pathogens (e.g., methicillin resistant Staphylococcus
aureus [MRSA]), in indoor air is important for understanding disease transmission from personto-
person. Common genera found in the human skin microbiome include Micrococcus and Staphylococcus,
but there only a limited number of tests to differentiate these genera and/or species. Both genera
are believed to be released into indoor air from the shedding of human skin and are morphologically
difficult to distinguish. In the current work, after the extraction of proteins from micrococci and the
separation of these proteins on one dimensional electrophoretic gels, tryptic peptides were analyzed by
MALDI TOF MS and the mass profiles compared with those of a reference strain (ATCC 4698). The results
confirmed that all strains were consistent in identity with Micrococcus luteus.