title: A comparison ofClostridium difficilediagnostic methods for identification of local strains in a South African centre.
abstract: Accurate diagnosis ofClostridium difficileinfection is essential for disease management. A clinical and molecular analysis ofC. difficileisolated from symptomatic patients at Groote Schuur Hospital, South Africa, was conducted to establish the most suitable clinical test for the diagnosis and characterization of locally prevalent strains.C. difficilewas detected in stool samples using enzyme-based immunoassays (EIA) and nucleic acid amplification methods, and their performance was compared with that ofC. difficileisolation using direct selective culture combined with specific PCR to detect theC. difficile tpigene, toxin A and B genes and binary toxin genes. Toxigenic isolates were characterized further by ribotyping. Selective culture isolated 32C. difficilestrains from 145 patients (22 %). Of these, the most prevalent (50 %) were of ribotype 017 (toxin A-B+) while 15.6 % were ribotype 001 (toxin A+B+). No ribotype 027 strains or binary toxin genes (cdtAandcdtB) were detected. The test sensitivities and specificities, respectively, of four commercial clinical diagnostic methods were as follows: ImmunoCardToxins A & B (40 % and 99.1 %), VIDASC. difficileToxin A & B (50 % and 99.1 %), GenoType CDiff (86.7 % and 88.3 %) and XpertC. difficile(90 % and 97.3 %). Ribotype 001 and 017 strains had a 100 % detection rate by XpertC. difficile, 100 % and 93.3 % by GenoType CDiff, 75 % and 53.3 % by ImmunoCardand 75 % and 60 % by VIDAS, respectively. The overall poor performance of EIA suggests that a change to PCR-based testing would assist diagnosis and ensure reliable detection of locally prevalentC. difficile017 strains.
authors: Department of Medicine, Division of Gastroenterology, University of Cape Town, Cape Town, South Africa.
authors: Naayil
authors: N
authors: Rajabally
authors: Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa.
authors: Brian
authors: B
authors: Kullin
authors: National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa.
authors: Kaleemuddeen
authors: K
authors: Ebrahim
authors: Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa.
authors: Tunehafo
authors: T
authors: Brock
authors: Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital, Huddinge, 14186 Stockholm, Sweden.
authors: Andrej
authors: A
authors: Weintraub
authors: National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa.|Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa.
authors: Andrew
authors: A
authors: Whitelaw
authors: National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa.|Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa.
authors: Colleen
authors: C
authors: Bamford
authors: Department of Medicine, Division of Gastroenterology, University of Cape Town, Cape Town, South Africa.
authors: Gillian
authors: G
authors: Watermeyer
authors: Department of Medicine, Division of Gastroenterology, University of Cape Town, Cape Town, South Africa.
authors: Sandie
authors: S
authors: Thomson
authors: Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa.
authors: Valerie
authors: V
authors: Abratt
authors: Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa.
authors: Sharon
authors: S
authors: Reid