[Comparison of usefulness between variable numbers of tandem repeats (VNTR) analysis and restriction fragment length polymorphism (RFLP) in the genotyping of Mycobacterium avium].
OBJECTIVE
Comparison of usefulness of IS1245 RFLP and VNTR in M. avium genotyping.


METHODS
Thirty-six cases (55 strains) from sputum and BALF and twelve cases (29 strains) isolated from blood of HIV-infected patients were used. VNTR and RFLP using IS1245 were performed.


RESULTS
Multiple samples were taken from 16 patients and 52 clinical isolates were used for VNTR and RFLP for comparison. (1) VNTR and RFLP results were identical in 12 out of 16 cases whose samples were collected several times. (2) Eight isolates were obtained from one patient. In this eight isolates, there were the cases of M. avium polyclonal infection and of mixed infection with M. intracellulare. VNTR patterns were two types and RFLP were 5 kinds of different in this case. (3) VNTR patterns of six isolates from one HIV-infected patient were identical, but there were three variations in RFLP patterns. There were three cases of mixed infections with M. tuberculosis or M. intracellulare, and six strains polyclonal infection of M. avium (7.1 %) in 84 isolates. These 6 clinical isolates were derived from sputum or BALF (5 strains) and HIV-infected blood (one strain). VNTR patterns were similar in four pairs (9 strains) who did not contact closely, but they were distinguished clearly by RFLP. Seventeen strains had three or less IS1245-related bands in RFLP analyses of 89 strains.


CONCLUSIONS
As there is a possibility of polyclonal infection with M. avium and mixed infection with other species, the single clonal infection should be confirmed first by VNTR. When single colony was obtained, VNTR and RFLP were performed for genotyping of M. avium. Furthermore, strains with less bands by RFLP should be carefully judged in terms of both VNTR and RFLP. It is recommended that the specimens should be collected from each patient several times.
Kazumi
Yuko
Y
TB Information Division (Molecular Epidemiology & Genetic Identification), Mycobacterium Reference Center, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose-shi, Tokyo. kazumi@jata.or.jp
Udagawa
Tadashi
T
Maeda
Shinji
S
Murase
Yoshirou
Y
Sugawara
Isamu
I
Okumura
Masao
M
Azuma
Yuka
Y
Goto
Mieko
M
Tsunematsu
Noriko
N
D001769:Blood / Q000382:microbiology; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D005838:Genotype; D015658:HIV Infections / Q000382:microbiology; D006801:Humans; D018598:Minisatellite Repeats; D009162:Mycobacterium avium / Q000235:genetics* / Q000302:isolation & purification; D012150:Polymorphism, Restriction Fragment Length; D013183:Sputum / Q000382:microbiology; D014376:Tuberculosis / Q000382:microbiology