Rapid Detection of Rifampin Resistant Mycobacterium tuberculosis Using the Line Probe Assay

Lee, Mi Kyoung; Park, Ae Ja; Jeon, Hee Sun

Abstract

BACKGROUND: Tuberculosis continues to be a major threat to health throughout the world, with an estimated 8 to 10 million new cases and 3 million deaths annually. And control of the disease is further threatened by the emergence of drug resistance. Recent major advances have been made in unravelling the molecular basis of M. tuberculosis resistance to isoniazid, streptomycin, quinolones and rifampin. And rifampin resistance is the useful indicator for the occurance of the multi-drug resistance. Hence, the rapid detection of rifampin resistant strain of M. tuberculosis is the key to have successful anti-tuberculosis therapy. Here we present our experience using PCR and line probe assay (INNO-LiPA) for easy and rapid detection of rifampin resistance of M. tuberculosis.
METHODS
Thirty rifampin resistant and twenty susceptible strains of M. tuberculosis were collected from the routine culture and analyzed with INNO-LiPA. And results were compared with conventional antibiotic susceptibility testing. After amplification of the region of the RNA polymerase(rpoB), the amplified product is hybridized with a set of 10 oligonucleotides immobilized onto a membrane strip. From the pattern obtained the presence or not of rifampin resistance M. tuberculosis can be assessed.
RESULTS
Ninety three percent of patients who had rifampin resistant strain revealed the multidrug resistance while only two showed resistance to rifampin only. The INNO-LiPA test results were generally agreeable with that of the conventional susceptibility testing(90%). The mutations in codon 531 (absence of 55 probe) were most commonly observed. In 55.2% of the 31 rifampin resistance M. tuberculosis confirmed on mutation by R-probes on the INNO-LiPA strips.
CONCLUSIONS
The line probe assay after polymerase chain reaction is a fast and convenient method to detect both presence of M. tuberculosis complex strains and its resistance to rifampin in clinical specimens. We have suggested that detection of rifampin resistance may play a key role in monitoring multi-drug resistance. Consequently, the INNO-LiPA test may constitute an important tool for the control of tuberculosis.