Clostridium difficile outcomes difficult to generalize

in which Zahar and colleagues [1] described Clostridium diffi cile infection (CDI) in patients during an intensive care unit (ICU) stay. Given some limitations of the authors’ study, it is diffi cult to generalize from the results that CDI detected early will not aff ect ICU length of stay or mortality. Th e carrier eff ect, in which up to 20% of hospitalized patients can be chronic carriers of C. diffi cile, can aff ect results [2]. Unfortunately, chronic carriers are not identifi ed. Furthermore, the 72-hour cutoff for ICU-acquired C. diffi cile seems somewhat arbitrary as it can be acquired faster and some patients were admitted to the ICU within the fi rst 72 hours of hospital exposure [3]. In addition, variance in the fi rst-line treatment of acquired CDI and its eff ect on treatment outcomes is unreported. Also, the detection immunoassay used a sensitivity well below (80%) those of the widely available cytotoxin neutralization assay (96%) and toxigenic culture (100%) [4]. Next, it is unclear whether the two populations were equally sick. Th e (younger) patients with diarrheal C. diffi cile were mechanically ventilated longer and received more proton pump inhibitors. Accordingly, unreported severity descriptors such as leukocytosis or renal insuffi ciency could infl uence mor tality outcomes. Furthermore, total hospital length of stay should be compared since C. diffi cile diarrhea alone does not necessitate admission to the ICU. Th e retrospective cohort trial is appro priate, but testing stronger strains of C. diffi cile, using higher-sensitivity detection methods, and tracking the entire length of stay would more accurately support the authors’ conclusions.