(a-c) Abundance of universal bacterial 16S rRNA gene (a), P. acnes-specific 16S rRNA gene (b), S. epidermidis SodA gene (c), or Pseudomonas-specific 16S rRNA gene (d) was measured by real-time qPCR. Relative abundance of DNA for 16S rRNA gene was calculated with a ΔCt method. P. acnes and S. epidermidis were quantified by comparison to known colony forming units (CFUs) of these organisms. Pseudomonas species was quantified by comparison to known CFUs of Pseudomonas aeruginosa. Skin compartments including epidermis and stratum corneum, follicle, dermis, and subcutaneous adipose tissue was excised by LCM. Non-tissue control (NTC) processed from embedding material adjacent to the tissue sample, and sterile skeletal muscle biopsy tissue, are also shown as negative controls to detect contamination. Each point represents a separate individual skin biopsy. The biopsy number is shown in different color and identical to the data in . The skeletal muscle specimens shown were obtained from five different donors.