title: International typing study of toxin A-negative, toxin B-positive Clostridium difficile variants.
abstract: Clinically important strains of Clostridium difficile that do not produce toxin A but produce toxin B and are cytotoxic (A(-)/B(+)) have been reported from multiple countries. In order to compare the relatedness of these strains, we typed 23 A(-)/B(+) C. difficile isolates from the United Kingdom (6 isolates), Belgium (11 isolates), and the United States (6 isolates) by three well-described typing methods. Restriction endonuclease analysis (REA), PCR ribotyping, and serogrouping differentiated 11, 4, and 3 different strain types, respectively. Twenty-one of the 23 A(-)/B(+) variants had a 1.8-kb truncation of the toxin A gene characteristic of toxinotype VIII strains; 20 of the 21 toxinotype VIII-like strains were PCR type 17. PCR type 17 isolates could be differentiated into two separate strain groups by serogrouping and by REA. REA further discriminated these isolates into eight subgroups (REA types). PCR type 17-serogroup F-REA group CF isolates were recovered from all three countries, and one specific REA type, CF4, was recovered from patients with C. difficile disease in the United Kingdom and the United States. C. difficile A(-)/B(+) variants of apparent clonal origin are widely distributed in Europe and North America.
authors.affiliation: Department of Medicine, Veterans Administration Chicago Health Care System, Lakeside Division, and Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. sjohnson@lumc.edu
authors.forename: Stuart
authors.initials: S
authors.lastname: Johnson
authors.forename: Susan P
authors.initials: SP
authors.lastname: Sambol
authors.forename: Jon S
authors.initials: JS
authors.lastname: Brazier
authors.forename: Michel
authors.initials: M
authors.lastname: Delmée
authors.forename: V
authors.initials: V
authors.lastname: Avesani
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Merrigan
authors.forename: Dale N
authors.initials: DN
authors.lastname: Gerding
mesh_terms: D000328:Adult; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism; D015373:Bacterial Typing Techniques; D001530:Belgium; D002648:Child; D016360:Clostridioides difficile / Q000145:classification* / Q000235:genetics; D004761:Enterocolitis, Pseudomembranous / Q000382:microbiology; D004768:Enterotoxins / Q000235:genetics* / Q000378:metabolism; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007391:International Cooperation; D016133:Polymerase Chain Reaction; D000091402:Prohibitins; D015183:Restriction Mapping; D021521:Ribotyping; D012703:Serotyping; D006113:United Kingdom; D014481:United States
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; C000717331:PHB2 protein, human; D000091402:Prohibitins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile