Characterization of bacterial isolates from patients with hidradenitis suppurativa

Background Hidradenitis suppurativa (HS) is a chronic, inflammatory, recurrent, and debilitating skin disease. GAP Statement In Japan, the skin flora of the affected areas of patients with HS has not been fully investigated. Aim This study investigated bacterial species isolated from HS lesions and evaluated their antimicrobial susceptibility. Methodology A total of 47 strains isolated from 18 patients with HS at the Toranomon Hospital Dermatology Department were used. Bacterial species were identified using 16S rDNA gene analysis. Results As a result, coagulase-negative staphylococci were the most frequently isolated species, followed by several other bacteria, including Streptococcus spp., Corynebacterium spp., Cutibacterium spp., Pseudomonas aeruginosa, Bacteroides fragilis, Peptoniphilus coxii, and Peptoniphilus harei/asaccharolyticus. We evaluated the susceptibility of these isolates to various antimicrobial agents. All the strains were highly susceptible to fusidic acid and rifampicin. In contrast, Staphylococcus spp., Enterococcus spp., Corynebacterium spp., and Streptococcus spp. exhibited high rates of resistance to tetracyclines and macrolides. Detection of antimicrobial resistance genes in these strains revealed that 100% of Corynebacterium spp. carried erm(X), 60.0% of Streptococcus spp. carried erm(B), and 60.0% of coagulase-negative staphylococci strains carried erm(C). Additionally, 80.0% of Streptococcus spp. and 50.0% of Enterococcus spp. carried the tet(K). Conclusions Our findings show that bacteria isolated from patients with HS have a high frequency of indigenous bacteria that are resistant to antimicrobial agents. These results highlight the importance of appropriate antimicrobial agents for the treatment of patients with HS.