What bacteria are typically associated with Hidradenitis suppurativa?

Bacteria Typically Found in Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is primarily associated with mixed normal flora and skin commensals, with specific culture techniques revealing an abundance of gram-negative organisms in some lesions. 1

Bacterial Profile in HS Lesions

• Mixed normal flora and skin commensals are the main bacteria cultured from suppurative discharge in HS 1
• Specific culture techniques have identified an abundance of gram-negative organisms in some HS lesions 1
• Biofilms (aggregates of bacteria in protective extracellular polymeric substance) have been described in most HS skin samples, especially in sinus tracts, compared to control skin of healthy volunteers 1

Common Bacterial Species

• Coagulase-negative staphylococci (CNS) are frequently isolated from HS lesions 2, 3
• Staphylococcus lugdunensis has been cultured as a unique or predominant isolate from 58% of HS nodules and abscesses 4
• Polymicrobial anaerobic microflora is commonly found, particularly in chronic suppurating lesions, including:
  • Strict anaerobes 4
  • Milleri group streptococci 4
  • Actinomycetes 4
• Two gram-negative anaerobic rod taxa, Prevotella and Porphyromonas, have been identified as predominant in HS lesions 5
• Additional taxa associated with clinical severity include Fusobacterium and Parvimonas 5

Clinical Implications of Bacterial Findings

• At present, microbiologic screening has limited utility in routine HS management 1
• A negative culture may support a diagnosis of HS based on consensus-derived diagnostic criteria 1
• Culture is not recommended in clinical practice unless signs of secondary infection such as surrounding cellulitis or fever are present 1
• The role of bacteria in HS pathogenesis is not yet fully elucidated, though biofilms may offer a therapeutic target for HS in the future 1

Treatment Considerations

• Antibiotics active against the bacterial flora in HS include:
  • Tetracyclines, clindamycin, and rifampicin for coagulase-negative staphylococci 2
  • Metronidazole, beta-lactams, and lincosamides for anaerobes 2
• Combined antibiotic therapy is often used, with rifampicin and clindamycin being a common combination for major or continuous forms of HS 2, 6
• Antibiotics may improve or lead to clinical remission, suggesting microbial factors play a role in HS 5

Important Caveats

• While bacteria are present in HS lesions, the disease is primarily considered inflammatory rather than infectious 1
• The bacteria found may be secondary colonizers rather than primary causative agents 1
• Long-term antibiotic use carries risks, even in otherwise healthy young adults typically affected by HS 2
• Surgical approaches remain important in HS management and cannot be replaced by antibiotics alone 2, 6