title: Clinical implications of Mycobacterium kansasii species heterogeneity: Swiss National Survey.
abstract: Several subtypes of Mycobacterium kansasii have been described, but their respective pathogenic roles are not clear. This study investigated the distribution of subtypes and the pathogenicity of M. kansasii strains (n = 191) isolated in Switzerland between 1991 and 1997. Demographic, clinical, and microbiological information was recorded from clinical files. Patients were classified as having an infection according to the criteria of the American Thoracic Society. Subtypes were defined by PCR-restriction enzyme analysis of the hsp65 gene. Subtype 1 comprised 67% of the isolates (n = 128), while subtypes 2 and 3 comprised 21% (n = 40) and 8% (n = 15), respectively. Other subtypes (subtypes 4 and 6 and a new subtype, 7) were recovered from only 4% of patients (n = 8). M. kansasii subtype 1 was considered pathogenic in 81% of patients, while M. kansasii subtype 2 was considered pathogenic in 67% of patients and other subtypes were considered pathogenic in 6% of patients. The majority of patients with M. kansasii subtype 2 were immunocompromised due to the use of corticosteroids (21% of patients) or coinfection with HIV (62.5% of patients). Subtyping M. kansasii may improve clinical management by distinguishing pathogenic from nonpathogenic subtypes.
authors.affiliation: Department of Microbiology. Division of Infectious Diseases, University Hospital, Lausanne, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Taillard
authors.forename: Gilbert
authors.initials: G
authors.lastname: Greub
authors.forename: Rainer
authors.initials: R
authors.lastname: Weber
authors.forename: Gaby E
authors.initials: GE
authors.lastname: Pfyffer
authors.forename: Thomas
authors.initials: T
authors.lastname: Bodmer
authors.forename: Stefan
authors.initials: S
authors.lastname: Zimmerli
authors.forename: Reno
authors.initials: R
authors.lastname: Frei
authors.forename: Stefano
authors.initials: S
authors.lastname: Bassetti
authors.forename: Peter
authors.initials: P
authors.lastname: Rohner
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Piffaretti
authors.forename: Enos
authors.initials: E
authors.lastname: Bernasconi
authors.forename: Jacques
authors.initials: J
authors.lastname: Bille
authors.forename: Amalio
authors.initials: A
authors.lastname: Telenti
authors.forename: Guy
authors.initials: G
authors.lastname: Prod'hom
mesh_terms: D000328:Adult; D003625:Data Collection; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D019909:Mycobacterium kansasii / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D013557:Switzerland