Composition and antimicrobic resistance of skin flora in hospitalized and healthy adults

The aerobic bacterial flora of the skin of the anterior nares, axilla, perineum, and toe web in a group of 37 patients hospitalized for at least 2 weeks was compared with the flora of 30 healthy adults. Colony counts were significantly higher for flora of the perineum and toe web in both groups (P less than 0.05). Patients had significantly higher carriage rates of Proteus, Pseudomonas, and Candida spp. (P less than 0.01). Staphylococcus haemolyticus was isolated more frequently from patients, and S. hominis was isolated more frequently from controls (P less than 0.01). Patient microflora, including gram-positive cocci, gram-negative bacilli, large-colony diphtheroids, and lipophilic diphtheroids, showed a high degree of resistance to multiple antimicrobial agents. The gram-positive coccal flora of patients was significantly more resistant than that of controls for 8 of 10 antimicrobial agents tested. Methicillin resistance occurred in only 2.9% of isolates from controls, but in 44.3% from patients (P less than 0.01). This extensive survey identifies qualitative and quantitative differences in skin flora and confirms that significantly higher levels of antimicrobial resistance are present in all types of organisms from a number of skin sites in hospitalized patients.