Clostridium difficile cytotoxin B in adults with diarrhea: a comparison of patients treated or not treated with antibiotics prior to infection

Objective   To study the detection rate of Clostridium difficile cytotoxin B in stool specimens from adults with diarrhea as related to previous antimicrobial treatment.
Methods   Stool specimens from 802 adult patients with diarrhea and 203 healthy controls were tested for C. difficile cytotoxin B using a cell cytotoxicity assay. Antibiotic susceptibility testing of C. difficile was performed with the E test.
Results   Of 173 patients treated with antimicrobial medication within 5 weeks of onset of diarrhea, 60 (35%) were positive for C. difficile cytotoxin B (group A) compared to only 41 (7%) of 629 untreated patients (group B) and two of the 203 (1%) healthy controls. Compared to patients in group A, patients in group B possessed characteristics not usually connected with C. difficile disease. They were generally younger (median age 40 years vs. 73 years), had been hospitalized less frequently (10% vs. 67%), had more often travelled abroad within the previous 2 weeks (46% vs. 1%), and more often had multiple enteropathogens (41% vs. 3%). Minimal inhibitory concentrations for vancomycin, metronidazole and fucidic acid to C. difficile isolates ranged from 0.5 to 4 mg/L, from 0.125 to 256 mg/L and 0.25 to 4 mg/L, respectively.
Conclusions   The detection rate of C. difficile cytotoxin B in patients with diarrhea, not associated with antibiotic treatment, is comparable to that in healthy control subjects. It probably merely reflects a carrier state without clinical significance.