Genetic and serovar typing of clinical isolates of the Mycobacterium avium-intracellulare complex.
METHODS
One hundred and thirty-four Mycobacterium avium-intracellulare complex (MAC) isolates were obtained from 121 patients in the UK.


OBJECTIVE
To compare serotyping and genetic analysis for species identification of MAC isolates from patients with and without the acquired immunodeficiency syndrome (AIDS).


METHODS
Clinical MAC isolates were cultured and analyzed by serotyping, the commercially available Accuprobe kit, hybridization with genes coding for the 19 kDa and 38 kDa antigens of M. tuberculosis and fingerprinting with the pMB22 probe derived from M. paratuberculosis.


RESULTS
Species classification on the basis of genetic analysis was similar to serovar typing, with only exceptional discrepancies. Serovar prevalence was different in the two groups of patients, and different from those reported in other countries. MAC isolates from AIDS patients were exclusively M. avium, whereas patients without AIDS had MAC infections with M. avium and M. intracellulare in about equal proportion. M. intracellulare clinical isolates were genetically more heterogeneous than M. avium. Only M. intracellulare hybridized with the 38 kDa gene probe.


CONCLUSIONS
Serovars are strongly linked with species in clinical MAC isolates, confirming results previously obtained with reference strains. M. intracellulare can be easily identified by the presence of a 38 kDa gene.
De Smet
K A
KA
MRC Tuberculosis and Related Infections Unit, Hammersmith Hospital, London, UK.
Hellyer
T J
TJ
Khan
A W
AW
Brown
I N
IN
Ivanyi
J
J
D017088:AIDS-Related Opportunistic Infections / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D015139:Blotting, Southern; D015342:DNA Probes; D005821:Genetic Techniques; D006801:Humans; D015269:Mycobacterium avium Complex / Q000145:classification* / Q000235:genetics; D015270:Mycobacterium avium-intracellulare Infection / Q000382:microbiology*; D012150:Polymorphism, Restriction Fragment Length; D011933:Reagent Kits, Diagnostic; D012703:Serotyping
D015342:DNA Probes; D011933:Reagent Kits, Diagnostic