Stuart Johnson, MD; Sara A. Kent, MD; Kevin J. O'Leary, MD; Michelle M. Merrigan, MS; Susan P. Sambol, BS; Lance R. Peterson, MD; Dale N. Gerding, MD
Many clinical laboratories use toxin A immunoassays to test for Clostridium difficile.
To describe the clinical course of a patient infected with a toxin variant strain of C. difficile that was not detected by toxin A immunoassay; to genetically characterize this strain; and to estimate the number of laboratories that use only toxin A immunoassays.
Case report, molecular investigation, and laboratory survey.
Tertiary care hospital in Chicago, Illinois.
An 86-year-old man.
Restriction endonuclease analysis, polymerase chain reaction, and survey of regional clinical laboratories.
An elderly hospitalized man died of advanced pseudomembranous colitis. Four stool specimens submitted over a 2-month period had tested negative on toxin A immunoassay, but a strain of C. difficile with a 1.8-kb deletion of the toxin A gene was recovered from each specimen. This strain, identified as restriction endonuclease analysis type CF4, is closely related to a widely disseminated variant, toxinotype VIII. Toxin A immunoassay was the only test being performed for detection of C. difficile at 31 of 67 (46%) regional clinical laboratories.
Toxin A variant strains of C. difficile cause serious disease and are undetectable in clinical laboratories that use only toxin A immunoassays for C. difficile testing.
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Johnson S, Kent SA, O'Leary KJ, Merrigan MM, Sambol SP, Peterson LR, et al. Fatal Pseudomembranous Colitis Associated with a Variant Clostridium difficile Strain Not Detected by Toxin A Immunoassay. Ann Intern Med. 2001;135:434-438. doi: 10.7326/0003-4819-135-6-200109180-00012
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Published: Ann Intern Med. 2001;135(6):434-438.
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Print ISSN: 0003-4819 | Online ISSN: 1539-3704
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