Table 1.
Summary of studies exploring the presence of dual/mixed strain Clostridium difficile infection.
| Author + year | Isolate selection | C. difficile identification | Number of cases | Culture method | No. of colonies tested per case | C. difficile strain differentiation | Cases with more than 1 C. difficile strain |
|---|---|---|---|---|---|---|---|
| Borriello and Honour, 1983 | 6 patients with antibiotic associated diarrhea and 1 with diarrhea unrelated to antibiotic use | C. difficile analytical profile index (API). Growth of isolates inhibited by Clostridium beijerinckii | 7 | Cycloserine cefoxitin agar. | At least 10 | Examined for production of cytotoxin using MRC-5 and VERO cells. Identified toxin producing and non-producing strains | 7 |
| Sharp and Poxton, 1985 | 4 strains of stored C. difficile isolates | Unspecified | 3 | Cycloserine cefoxitin fructose agar (CCFA) | 8 | Ethylenediaminetetraacetic acid (EDTA) antigen extraction and immunoblotting | 2 |
| Devlin et al., 1987 | 110 stored clinical isolates | Unspecified | 110 | Cycloserine-cefoxitin-fructose agar with sodium taurocholate (TCCFA). | Approximately 10 | Plasmid profile and restriction enzyme analysis (REA) | 0 |
| O’Neill et al., 1991 | 10 patients with >1 isolation of C. difficile | Latex particle agglutination test | 10 | CCFA | 10 | REA Examined for production of cytotoxin using VERO cells | 0 |
| Wilcox et al., 1998 | Frozen isolates from patients with >2 C. difficile cytotoxin positive fecal samples | Colonial morphology, odor and RapID ANA II | 27 | Cycloserine, cefoxitin, egg yolk agar | 1–2 | Random amplified polymorphic DNA (RAPD) | 0 |
| van den Berg et al., 2005 | Frozen isolates from patients with first episodes of C. difficile associated diarrhea | Enzyme linked fluorescence assay and culture | 23 | Columbia agar with colistin + nalidixic acid and/or C. difficile agar with moxalactam and cysteine. | Approximately 5 | PCR ribotyping, toxinogenicity and clindamycin resistance | 2 |
| Tanner et al., 2010 | Pre-selected from a pool of cases typed as 027 strain | PCR ribotyping | 39 | CCFA | 5 | Multilocus variable number tandem repeat analysis (MLVA) | 5 |
| Kamboj et al., 2011 | Patients with 2 episodes of C. difficile infection occurring >2 weeks apart identified using microbiology records | C. difficile neutralization assay and enzyme immunoassay (EIA) for glutamate dehydrogenase (GDH) | 102 | Unspecified | Unspecified | PCR ribotyping | 0 |
| Hell et al., 2011 | Patients with nosocomial C. difficile chosen arbitrarily | Enzyme linked immunosorbent assay (ELISA) for C. difficile TcdA and TcdB | 11 | Cycloserine/cefoxitin agar | 5 | PCR ribotyping | 1 |
| Eyre et al., 2012 | Paired stool samples from patients collected on the same day | EIA for GDH and culture | 305 | Unspecified | Unspecified | Multilocus sequence typing (MLST) | 21 |
| Behroozian et al., 2013 | Stored isolates from C. difficile infected patients | 3 step diagnostic algorithm: (1) EIA for GDH; (2) EIA for C. difficile toxin A and/or B; (3) PCR for presence of tcdB gene | 102 | Pre-reduced, TCCFA | 95 | PCR ribotyping | 16 |
| Sun et al., 2016 | Patients with >1 episode of CDI occuring at least 8 weeks apart | Stool sample positive by PCR for C. difficile. | 52 | Not specified | 5 | MLST | 4 |