Differences in skin flora between inpatients and chronically ill outpatients

Changes in skin flora have been reported among hospitalized and critically ill patients, but little is known about whether these changes are associated with hospitalization or with chronic, serious illness. The purpose of this survey was to compare skin flora of chronically ill outpatients and inpatients.

Aerobic skin flora of forearm and midsternum of 250 patients in an intensive care unit and 251 outpatients was sampled by contact plates.

Mean colony-forming units were 160.6, forearm; 229. 4, sternum (P <.000). In logistic regression analysis, patients in the medical intensive care unit were significantly more likely to have high counts on the arm (odds ratio, 2.48; 95% confidence interval: 1.34-4.43; P =.004), and blacks were significantly more likely to have higher counts on the sternum when compared with other ethnic groups (odds ratio, 1.92; confidence interval: 1.18-3.11; P =. 009). No differences were noted between inpatients or outpatients in prevalence of methicillin-sensitive Staphylococcus aureus, but inpatients were more likely to carry methicillin-resistant Staphylococcus aureus (arm, P =.007; sternum, P =.02). Outpatients had a higher prevalence of micrococci and gram-negative bacteria at both skin sites (all P <.01) and yeast at the sternal site (P =.007).

This comparison provides data to differentiate between effects of hospitalization and effects of chronic illness on skin flora.