title: Pseudomembranous colitis caused by toxin A-negative/toxin B-positive variant strain of Clostridium difficile.
abstract: We report the first case of pseudomembranous colitis (PMC) due to a toxin A-negative, toxin B-positive strain (toxin A variant strain) of Clostridium difficile in Japan. The toxin A variant strain of C. difficile is capable of causing PMC and is undetectable in clinical laboratories that use only toxin A immunoassays for C. difficile testing. If C. difficile-associated diarrhea is clinically suspected and toxin A is not detected, then the possibility of a toxin A variant strain should be considered, and further diagnostic testing, such as polymerase chain reaction (PCR) analysis for the detection of C. difficile toxin genes should be performed.
authors.affiliation: Laboratory for Clinical Investigation, Osaka University Hospital, Osaka University, 2-15 Yamadaoka, Suita, 565-0871 Osaka, Japan. toyokawa@hp-lab.med.osaka-u.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Toyokawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Ueda
authors.forename: Hisako
authors.initials: H
authors.lastname: Tsukamoto
authors.forename: Isao
authors.initials: I
authors.lastname: Nishi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Horikawa
authors.forename: Atsuko
authors.initials: A
authors.lastname: Sunada
authors.forename: Seishi
authors.initials: S
authors.lastname: Asari
mesh_terms: D000368:Aged; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D016360:Clostridioides difficile / Q000235:genetics / Q000378:metabolism*; D004761:Enterocolitis, Pseudomembranous / Q000175:diagnosis* / Q000382:microbiology*; D004768:Enterotoxins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007118:Immunoassay; D016133:Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile