Skin test reactivity to mycobacterial antigens parallels the phylogenetic structure of their genus.
METHODS
City of Manaus, Amazonas, Brazil.


OBJECTIVE
To explore the relationship between positivity to tuberculin and other environmental mycobacteria sensitins, according to a range of criteria and presence of BCG scar.


METHODS
Dual skin testing with tuberculin and four mycobacterial sensitins, and BCG scar recording of 1070 schoolchildren aged 7-14. Four criteria for positivity were used: simple and dominant, with 5 and 10 mm cut-off points.


RESULTS
The standardised prevalence of reactions > or = 5 mm for BCG scar negative children was 58.3% for Mycobacterium avium, 54.2% for M. scrofulaceum, 26.8% for M. fortuitum, 17.9% for M. tuberculosis and 7.6% for M. kansasii. Correlations between tuberculin and each sensitin, for BCG scar negative children, were 0.47 for M. avium, 0.53 for M. scrofulaceum, 0.60 for M. kansasii and 0.22 for M. fortuitum (all with P < 0.01). BCG effect was particularly significant for tuberculin (odds ratio = 3.44 for reactions > or = 5 mm, P < 0.001) and influenced the balance between dominant/non-dominant reactions for all sensitins.


CONCLUSIONS
The correlation between tuberculin and each sensitin confirmed the separation of the rapidly (M. fortuitum) and slowly growing mycobacteria (M. tuberculosis, M. avium, M. scrofulaceum and M. kansasii). The influence of BCG on tuberculin reactions was more marked than on other mycobacterial sensitins.
Bierrenbach
A L
AL
London School of Hygiene and Tropical Medicine, London University, UK. ana.bierrenbach@lshtm.ac.uk
Cunha
S S
SS
Barreto
M L
ML
Pereira
S M
SM
Rodrigues
L C
LC
D000293:Adolescent; D000942:Antigens, Bacterial; D001500:BCG Vaccine; D002648:Child; D003429:Cross Reactions; D000939:Epitopes; D005260:Female; D006801:Humans; D008297:Male; D009161:Mycobacterium / Q000276:immunology*; D009162:Mycobacterium avium / Q000276:immunology; D019907:Mycobacterium fortuitum / Q000276:immunology; D019909:Mycobacterium kansasii / Q000276:immunology; D015359:Mycobacterium scrofulaceum / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000276:immunology; D012882:Skin Tests
D000942:Antigens, Bacterial; D001500:BCG Vaccine; D000939:Epitopes