Klebsiella aerogenes Skin Infections
Klebsiella aerogenes (formerly Enterobacter aerogenes) causes necrotizing fasciitis as its most clinically significant skin infection, though it is a less common cause than streptococci or MRSA. 1
Primary Skin Infection Types
Necrotizing Fasciitis
- K. aerogenes is specifically identified as a causative pathogen of necrotizing fasciitis, a life-threatening necrotizing cutaneous infection that requires immediate recognition and surgical intervention 1
- This infection typically occurs following penetrating wounds to the extremities and can occasionally occur without identifiable trauma 1
- Necrotizing fasciitis caused by Klebsiella species (including K. aerogenes) is less common than streptococcal or MRSA-associated cases but carries similar mortality risk 1
Folliculitis
- K. aerogenes ST117 has recently emerged as a causative agent of folliculitis specifically in men who have sex with men (MSM) 2
- This strain carries yersiniabactin siderophore genes and demonstrates treatment resistance, with recurrence after initial sulfamethoxazole-trimethoprim therapy requiring extended treatment regimens 2
Surgical Site and Graft Infections
- K. aerogenes causes nosocomial surgical site infections, particularly involving implanted materials with poor vascularization such as costochondral grafts in rhinoplasty 3
- These infections are opportunistic and occur when antibiotics have difficulty reaching the surgical site due to limited blood supply 3
Clinical Context and Risk Factors
Healthcare-Associated Infections
- K. aerogenes is primarily a nosocomial pathogen causing opportunistic infections in healthcare settings 3, 4
- The organism demonstrates high genomic diversity with multiple clonal complexes (at least 10 CCs), with CC3 comprising the majority of hospital outbreak-associated isolates 4
Skin Colonization Patterns
- During healthcare outbreaks, K. aerogenes colonizes not only mucosal surfaces but also remote skin sites including hands, knees, groins, and umbilicus 5
- This extensive skin colonization facilitates transmission in healthcare settings and can serve as a reservoir for subsequent infection 5
Important Clinical Pitfalls
Critical distinction: While Klebsiella pneumoniae (a different species) causes complicated skin and soft tissue infections with gas formation, pyomyositis, and metastatic infections particularly in cirrhotic patients 6, K. aerogenes has a more limited but specific role in necrotizing fasciitis and emerging folliculitis cases 1, 2
Antibiotic resistance considerations: K. aerogenes carries extensive resistance genes including antibiotic efflux proteins and β-lactamases, with documented gentamicin resistance and R-factor mediated multi-drug resistance 5, 4