Evolving Strategies to Manage Clostridium difficile Colitis

Clostridium difficile infection remains a common nosocomial illness with a significant impact on health care delivery. As molecular phenotyping of this organism has changed our understanding of its transmission and virulence, so too have diagnostic methods and treatment strategies evolved in recent years. The burden of this infection falls predominantly on elderly patients with comorbidities who have recently received antibiotics. Oral or enteral vancomycin is now preferred for first-line antimicrobial treatment across the disease spectrum, including mild-moderate initial cases. Fidaxomicin (a novel macrolide antibiotic), bezlotoxumab (a monoclonal antibody against toxin TcdB), and fecal microbiota transplantation expand the therapeutic armamentarium, particularly for recurrent infection. Operative treatment should be reserved for patients with fulminant infection, and early identification of patients who would benefit from an operation remains a challenge. Less invasive surgical options-such as laparoscopic diverting ileostomy with colonic irrigation-may improve survival and other outcomes relative to total abdominal colectomy and represent an attractive alternative particularly for frail patients.

Selected Topics in Anaerobic Bacteriology

Alteration in the host microbiome at skin and mucosal surfaces plays a role in the function of the immune system, and may predispose immunocompromised patients to infection. Because obligate anaerobes are the predominant type of bacteria present in humans at skin and mucosal surfaces, immunocompromised patients are at increased risk for serious invasive infection due to anaerobes. Laboratory approaches to the diagnosis of anaerobe infections that occur due to pyogenic, polymicrobial, or toxin-producing organisms are described. The clinical interpretation and limitations of anaerobe recovery from specimens, anaerobe-identification procedures, and antibiotic-susceptibility testing are outlined. Bacteriotherapy following analysis of disruption of the host microbiome has been effective for treatment of refractory or recurrent Clostridium difficile infection, and may become feasible for other conditions in the future.