VIII. METHODS FOR TYPING MYCOBACTERIA
359
or B. (In a study of seven strains from India, Tokunaga et al. (1968)
reported two which showed intermediate degrees of susceptibility to GS4E
and BK1.) Second, it was found that tubercle bacilli were not evenly distributed geographically according to phage type. Type B strains were more
common in Britain than in Hong Kong or southern India, the Type A
strains predominated in Hong Kong, and the “intermediate” strains
together with the Type A strains were observed in southern India. Type C
strains were not observed among any of the strains in this study. Third, it
was found that the phage type did not change despite in vivo changes in
drug susceptibility, animal virulence, or catalase production. Fourth, it
was found that phage type did not correlate with drug resistance when
Isoniazid, Streptomycin, and para-aminosalicylic acid were the drugs
studied. Fifth, it was observed that the southern Indian Isoniazid-sensitive
strains of decreased virulence for guinea-pigs were randomly distributed
between phage Type A and the “intermediate” type.
Another large epidemiological study was reported by Baess (1969) who
evaluated 230 strains obtained from Danish patients who were linked
epidemiologically. Phage BK1 divided 205 human strains into 62 phagesusceptible and 143 phage-resistant strains. (Of 88 groups of patients with
a presumed epidemiological relation within each group, 22 groups harboured only phage-susceptible and 61 only phage-resistant strains.) Five
patient groups harboured both phage-resistant and phage-susceptible
strains. Baess found only a few strains lysed by D34, observed that the
plaques produced by it were turbid, and expressed concern that D34 would
not be a useful phage for epidemiological studies. An additional five phages
were used by Baess and none served to subdivide the tubercle bacilli into
more types than the two shown by BK1.
Thereafter several additional epidemiological studies were reported by
investigators who continued using the techniques developed by Redmond
et al. (1963) or by Tokunaga and Morohashi (1963). Stead and Bates (1969)
used phage typing to support other epidemiological data which indicated
that a young soldier had become infected while on military assignement in
the Far East and upon returning to the United States had infected two
persons. Steiner et al. (1970) studied an outbreak of primary tuberculosis
where the source case was excreting organisms resistant to Isoniazid,
Streptomycin, and para-aminosalicylic acid. The phage types of the epidemiologically related strains were identical in each instance, and when
correlated with the drug susceptibility pattern for the strains, confirmed
that this Isoniazid-resistant organism was highly infectious and virulent.
Stead and Bates (1971) used phage typing to study the pathogenesis of
tuberculosis by typing tubercle bacilli isolated from a chest wall abscess
which had developed following local trauma during an episode of primary
359
or B. (In a study of seven strains from India, Tokunaga et al. (1968)
reported two which showed intermediate degrees of susceptibility to GS4E
and BK1.) Second, it was found that tubercle bacilli were not evenly distributed geographically according to phage type. Type B strains were more
common in Britain than in Hong Kong or southern India, the Type A
strains predominated in Hong Kong, and the “intermediate” strains
together with the Type A strains were observed in southern India. Type C
strains were not observed among any of the strains in this study. Third, it
was found that the phage type did not change despite in vivo changes in
drug susceptibility, animal virulence, or catalase production. Fourth, it
was found that phage type did not correlate with drug resistance when
Isoniazid, Streptomycin, and para-aminosalicylic acid were the drugs
studied. Fifth, it was observed that the southern Indian Isoniazid-sensitive
strains of decreased virulence for guinea-pigs were randomly distributed
between phage Type A and the “intermediate” type.
Another large epidemiological study was reported by Baess (1969) who
evaluated 230 strains obtained from Danish patients who were linked
epidemiologically. Phage BK1 divided 205 human strains into 62 phagesusceptible and 143 phage-resistant strains. (Of 88 groups of patients with
a presumed epidemiological relation within each group, 22 groups harboured only phage-susceptible and 61 only phage-resistant strains.) Five
patient groups harboured both phage-resistant and phage-susceptible
strains. Baess found only a few strains lysed by D34, observed that the
plaques produced by it were turbid, and expressed concern that D34 would
not be a useful phage for epidemiological studies. An additional five phages
were used by Baess and none served to subdivide the tubercle bacilli into
more types than the two shown by BK1.
Thereafter several additional epidemiological studies were reported by
investigators who continued using the techniques developed by Redmond
et al. (1963) or by Tokunaga and Morohashi (1963). Stead and Bates (1969)
used phage typing to support other epidemiological data which indicated
that a young soldier had become infected while on military assignement in
the Far East and upon returning to the United States had infected two
persons. Steiner et al. (1970) studied an outbreak of primary tuberculosis
where the source case was excreting organisms resistant to Isoniazid,
Streptomycin, and para-aminosalicylic acid. The phage types of the epidemiologically related strains were identical in each instance, and when
correlated with the drug susceptibility pattern for the strains, confirmed
that this Isoniazid-resistant organism was highly infectious and virulent.
Stead and Bates (1971) used phage typing to study the pathogenesis of
tuberculosis by typing tubercle bacilli isolated from a chest wall abscess
which had developed following local trauma during an episode of primary