Microbiologic evaluation of skin wounds: alarming trend toward antibiotic resistance in an inpatient dermatology service during a 10-year period

BACKGROUND: Increasing resistance to commonly used antibiotics has been seen for patients with superficial skin wounds and leg ulcers. OBJECTIVES: We sought to evaluate bacterial isolates from leg ulcers and superficial wounds for resistance to commonly used antibiotics and to compare current data with previous data. METHODS: We performed a chart review for patients admitted to a tertiary care dermatology inpatient unit from January to December 2001. Comparison was made with 2 previous surveys of the same inpatient service from 1992 and 1996. RESULTS: Bacterial isolates were cultured from 148 patients, 84% (72 of 86) with leg ulcers and 38% (76 of 202) with superficial wounds. Staphylococcus aureus and Pseudomonas aeruginosa were the most common bacterial isolates in both groups. For patients with leg ulcers, S aureus grew in 67% of isolates (48/72) of which 75% (36/48) were methicillin-resistant (MRSA). Of leg ulcers, 35% (25/72) grew P aeruginosa, which was resistant to quinolones in 56% of cultures (14/25). For patients with superficial wounds, S aureus was isolated in 75% (57/76) and 44% were MRSA (25/57). P aeruginosa grew in 17% of isolates (13/76) and was resistant to quinolones in 18%. We found a marked increase in antibiotic resistance for both leg ulcers and superficial wounds. Over time, MRSA increased in leg ulcers from 26% in 1992 to 75% in 2001. For superficial wounds, MRSA increased from 7% in 1992 to 44% in 2001. P aeruginosa resistance to quinolones in leg ulcers increased from 19% in 1992 to 56% in 2001, whereas for superficial wounds there was no resistance in 1992 and 18% resistance in 2001. CONCLUSION: Rapid emergence of antibiotic-resistant bacteria continues and is a problem of increasing significance in dermatology. Common pathogenic bacteria, S aureus and P aeruginosa, showed increased resistance to commonly used antibiotics. Selection of antibiotics should be on the basis of local surveillance programs.