IS6110 based amplityping assay and RFLP fingerprinting of clinical isolates of Mycobacterium tuberculosis.
OBJECTIVE
To evaluate the usefulness of two IS6110 based typing methods, an amplityping assay and restriction fragment length polymorphism (RFLP) analysis, for fingerprinting respiratory isolates of Mycobacterium tuberculosis.


METHODS
For amplityping, a pair of primers which amplify the intervening sequence between the repetitive insertion sequence IS6110 was used to generate a banding pattern which was confirmed by hybridisation. This assay was compared with conventional chromosomal DNA RFLP typing in the evaluation of 110 epidemiologically diverse isolates.


RESULTS
Polymerase chain reaction (PCR) amplityping generated a single pattern in Hong Kong Chinese strains, but two and four diverse patterns in Filipino and Vietnamese strains, respectively, and could be completed within four days. When compared with chromosomal DNA RFLP typing, which took three weeks to complete, four different RFLP patterns could be seen among the Chinese strains, while seven patterns were found in the Filipino and Vietnamese strains. No change in amplityping or RFLP patterns was found in 36 sequential isolates from the same patients after anti-tuberculosis treatment for up to 12 months, despite the emergence of resistance in three of these strains. No specific amplityping or RFLP pattern could be related to different patterns of drug susceptibility.


CONCLUSIONS
PCR amplityping could be used initially as a rapid typing method to distinguish strains originating from different localities. This could be important for investigation of outbreaks of tuberculosis--for example, in refugee camps.
Department of Microbiology, University of Hong Kong, Hong Kong.
K Y
KY
Yuen
C M
CM
Chan
K S
KS
Chan
W C
WC
Yam
P L
PL
Ho
P Y
PY
Chau
D015373:Bacterial Typing Techniques / Q000592:standards*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000145:classification*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid
D004269:DNA, Bacterial