Clostridium difficile – Associated Diarrhea Outbreaks

Sir—We read with interest the article by Pépin et al. [1], which reports that use of quinolones is a major risk factor for illness during an outbreak of Clostridium difficile–associated diarrhea (CDAD). These results confirm previous observations that quinolones and other antibiotics, such as third-generation cephalosporins, macrolides, broad-spectrumb-lactams, and aminoglycosides, are important risk factors for CDAD [2, 3]. However, in addition to instating and/or following policies regarding antibiotic use, other infection-control procedures—including environmental hygiene, washing hands with soap and water, and isolating patients who have CDAD— are critical to the prevention of the spread of this disease [4, 5]. This outbreak has also been affecting our institution and has even forced medical units to be closed for varying lengths of time [6]. Interestingly, our institution does not have any respiratory quinolones on formulary and only uses ciprofloxacin. The fact that most patients are naive to treatment with respiratory quinolones leads us to believe that other factors have played a role in this outbreak. Another observation that the the incidence of CDAD markedly decreased during the first half of 2005 in institutions in Quebec initially affected by the outbreak [7]. This phenomenon does not appear to be related to changing patterns of specific antimicrobial agent use; rather, the decrease follows implementation of specific modification of infection-control and cleaning procedures driven by governmental incentives. Indeed, CDAD is affecting institutions regardless of which antibiotics are used. There are also no data demonstrating that the use of one agent over another has had an impact on the incidence of CDAD during the current outbreak. In our institution, the decreased incidence of CDAD does not correlate with use of any specific antibiotic, because there has been little change in the types of antibiotics prescribed to patients with CDAD during the past years, even though the incidence has gone from 140 cases per 1000 admissions to !12 cases per 1000 admissions. The identification of antibiotics most likely to contribute to C. difficile infection is an important piece of the puzzle. The data presented by Pépin et al. [1] demonstrate that antibiotic use is associated with development of CDAD, and that the judicious use of antibiotics only when indicated is probably appropriate. However, selecting specific antibiotics for use as a means of decreasing the risk of CDAD has yet to be properly demonstrated. In our hospital, the name of the game is still isolation of patients and cleaning.