Evaluation of phage assay for rapid phenotypic detection of rifampicin resistance in Mycobacterium tuberculosis.
BACKGROUND
Conventional methods for susceptibility testing require several months before results can be reported. However, rapid methods to determine drug susceptibility have been developed recently. Phage assay have been reported as a rapid useful tools for antimicrobial susceptibility testing. The aim of this study was to apply the Phage assay for rapid detection of resistance on Mycobacterium tuberculosis strains in Cuba.


METHODS
Phage D29 assay was performed on 102 M. tuberculosis strains to detect rifampicin resistance. The results were compared with the proportion method (gold standard) to evaluate the sensitivity and specificity of Phage assay.


RESULTS
Phage assay results were available in 2 days whereas Proportion Methods results were obtain in 42 days. A total of 44 strains were detected as rifampicin resistant by both methods. However, one strains deemed resistant by Proportion Methods was susceptible by Phage assay. The sensitivity and specificity of Phage assay were 97.8 % and 100% respectively.


CONCLUSIONS
Phage assay provides rapid and reliable results for susceptibility testing; it's easy to perform, requires no specialized equipment and is applicable to drug susceptibility testing in low income countries where tuberculosis is a major public health problem.
Yzquierdo
Sergio Luis
SL
Instituto de Medicina Tropical Pedro Kouri, La Habana, Cuba. sergioluis@ipk.sld.cu
Lemus
Dihadenys
D
Echemendia
Miguel
M
Montoro
Ernesto
E
McNerney
Ruth
R
Martin
Anandi
A
Palomino
Juan Carlos
JC
D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009160:Mycobacteriophages / Q000502:physiology*; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000821:virology*; D010641:Phenotype; D012293:Rifampin / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013997:Time Factors
D000904:Antibiotics, Antitubercular; D012293:Rifampin