Coagulase-negative staphylococci are the most common bacteria found in cultures from the deep portions of hidradenitis suppurativa lesions, as obtained by carbon dioxide laser surgery.

The significance of bacterial findings in hidradenitis suppurativa (HS) is controversial. Interpretation of the results of bacteriological examinations from the surface of HS lesions is obscured by the possible contamination of resident skin bacteria. Bacteriological analysis of aspirates from deeper parts of HS is liable to show low sensitivity. We used a carbon dioxide (CO2) laser method to evaporate the diseased tissue level by level from the surface downwards, allowing concurrent sampling of bacteriological cultures from each level and thereby minimizing contamination with bacteria from the level above. In this study, 22 women and three men with a mean age of 35.3 years and a mean HS duration of 10.6 years were treated with this CO2 laser surgical method. Aerobic and anaerobic cultures from superficial and deep levels were taken during surgery. The regions treated were axillary in eight and perineal in 17 cases. Bacterial cultures were positive for one or more specimens from at least one level in all cases and from deep levels in all but three cases. Sixteen different species or sub-species were found. Staphylococcus aureus and coagulase-negative staphylococci (CNS) were the species most frequently found. Peptostreptococcus species and Propionibacterium acnes were not uncommon. S. aureus was detected in a total of 14 cases, six of which were from the deep levels. S. aureus was the sole bacterium isolated in two deep cultures. CNS were found in 21 patients and 16 of these isolates were from the deep levels. In nine of the 16 deep samples CNS were the only bacteria detected. These findings motivate a re-evaluation of the significance of bacteria in the progress of HS and in particular they suggest that CNS are true pathogens. It is known that foreign bodies aggravate the virulence of the CNS in surgical implants, and an environment which resembles that produced by a foreign body, as found in chronic HS tissue, serves to intensify the pathogenic properties of CNS in HS.