Accelerated detection of Mycobacterium tuberculosis genes essential for bacterial survival in guinea pigs, compared with mice.
BACKGROUND
Mouse and guinea pig models have been used to identify Mycobacterium tuberculosis mutants attenuated for survival. However, unlike mice, M. tuberculosis-infected guinea pigs form caseating granulomas, which may simulate human disease more closely.


METHODS
We used designer arrays for defined mutant analysis, a high-throughput subtractive competition assay, for genotypically defined M. tuberculosis mutants and compared the survival of the same mutant pools in guinea pig and mouse aerosol models. Selected mutants found to be attenuated in either aerosol model were also analyzed in the mouse hollow-fiber model.


RESULTS
M. tuberculosis mutants representing 74 genes were tested. Eighteen M. tuberculosis mutants were attenuated for survival in either aerosol model, with 70% of selected mutants also attenuated in the mouse hollow-fiber model. The majority of attenuated mutants in the mouse aerosol model were detected only after 90 days of infection. There was a high degree of concordance between the genes identified by the 2 aerosol models, with detection being significantly earlier in the guinea pig (P<.0003).


CONCLUSIONS
We identified M. tuberculosis genes required for survival in mammalian lungs. The majority of mouse late-stage survival mutants were detected significantly earlier in the guinea pig, which suggests that differences in tuberculosis-induced lung pathologic changes may account for this accelerated detection.
Jain
Sanjay K
SK
Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA. sjain5@jhmi.edu
Hernandez-Abanto
S Moises
SM
Cheng
Qi-Jian
QJ
Singh
Prabhpreet
P
Ly
Lan H
LH
Klinkenberg
Lee G
LG
Morrison
Norman E
NE
Converse
Paul J
PJ
Nuermberger
Eric
E
Grosset
Jacques
J
McMurray
David N
DN
Karakousis
Petros C
PC
Lamichhane
Gyanu
G
Bishai
William R
WR
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004251:DNA Transposable Elements; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D008168:Lung / Q000382:microbiology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D016254:Mutagenesis, Insertional; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity*; D020411:Oligonucleotide Array Sequence Analysis; D013045:Species Specificity; D014397:Tuberculosis, Pulmonary / Q000382:microbiology* / Q000473:pathology
D001426:Bacterial Proteins; D004251:DNA Transposable Elements