Clinical implications of Mycobacterium kansasii species heterogeneity: Swiss National Survey.
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.
Taillard
Caroline
C
Department of Microbiology. Division of Infectious Diseases, University Hospital, Lausanne, Switzerland.
Greub
Gilbert
G
Weber
Rainer
R
Pfyffer
Gaby E
GE
Bodmer
Thomas
T
Zimmerli
Stefan
S
Frei
Reno
R
Bassetti
Stefano
S
Rohner
Peter
P
Piffaretti
Jean-Claude
JC
Bernasconi
Enos
E
Bille
Jacques
J
Telenti
Amalio
A
Prod'hom
Guy
G
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