[Application of rapid detection for rifampin resistance in clinical isolates of Mycobacterium tuberculosis by phage amplified biologically assay].
OBJECTIVE
To set up a rapid detection method for rifampin susceptibility with phage amplified biologically (PhaB) assay and to evaluates its value in the detection of rifampin resistance in clinical isolates of Mycobacterium tuberculosis.


METHODS
The assay was established to detect rifampin resistance in 524 clinical isolates of Mycobacterium tuberculosis, and the result was compared to that of the absolute concentration method. The minimum inhibitory concentration (MIC) was detected by BACTEC MGIT 960 method for the discrepant isolates.


RESULTS
Rifampin susceptibility results were available for 524 strains of Mycobacterium tuberculosis. A total of 223 strains were found to be rifampin resistant and 301 strains were rifampin susceptible detected by PhaB assay, but 211 and 313 strains were respectively found to be rifampin resistant and susceptible by conventional methods. There were 198 and 288 rifampin resistant and susceptible strains both detected by the two methods. The drug susceptibility of 35 strains was the same in 38 discrepant isolates by the PhaB assay and absolute concentration method. The sensitivity, specificity, positive and negative predictive values as well as the overall accuracy for the PhaB assay was 93.8%, 92.0%, 88.8%, 95.7% and 92.7% respectively if the judgment standard was adopted by conventional methods.


CONCLUSIONS
The result of PhaB assay was available within 2 days. This method, which is simple and does not need special equipment, can be used for rapid screening for rifampin resistance from Mycobacterium tuberculosis.
Hu
Zhong-Yi
ZY
Basic Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Shanghai 200433, China. huzhongyi@vip.citiz.net
Jin
An-Jia
AJ
Chen
Hui-Ping
HP
Cui
Zhen-Ling
ZL
Jing
Ling-Jie
LJ
Wang
Jie
J
Weng
Xin-Hua
XH
D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D009160:Mycobacteriophages; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D020411:Oligonucleotide Array Sequence Analysis; D012293:Rifampin / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013696:Temperature
D000904:Antibiotics, Antitubercular; D012293:Rifampin