A Study for Improvement of the Positive Culture Rate Using Skin Biopsy Specimens in Patients with Cellulitis

Lee, Jae Young; Park, Seok Don

Abstract

BACKGROUND: Staphylococcus aureus and group A streptococci are the most common etiologic agents in cellulitis, but occasionally many other bacteria are also identified. The positive rate of bacterial cultures taken from the skin lesion are low.
OBJECTIVE
This study aims to improve the positive culture rate in patients with cellulitis by using skin biopsy specimens in several kinds of media.
METHODS
Skin biopsy specimens taken from 54 patients with cellulitis were cultured in 4 functionally-different types of media (blood agar, MacConkey agar, chocolate agar, thioglycollate broth). Positive culture rates were evaluated in each medium and cultured bacteria were identified. Clinical characteristics were also studied, including age, sex, affected site, and history of previous treatment.
RESULTS
The sex ratio of males to females was 2.9: 1 and mean age was 49 years. The most commonly-involved site was the lower extremities (42.6%), followed by the upper extremities (13.0%), head and neck (9.3%), and trunk (1.9%). Patients who had received previous antimicrobial treatment numbered 31 cases (57.4%). Of the 23 patients who had received no previous antimicrobial treatment, 13 patients (56.5%) had positive cultures. The most common pathogens were S. aureus and Streptococcus sp. (59.1%), but seven different genus of bacteria were also isolated from 9 patients (40.9%). Thioglycollate broth yielded a high positive culture rate (38.9%) among the 4 types of culture media.
CONCLUSION
It is suggested that the bacterial culture of skin biopsy tissue from four functionally-different types of media is a useful method for improving positive bacterial culture rate in patients with cellulitis.