Comparative study between bactec magit 960 and fast plaque - response for susceptibility pattern to rifampicin in sputum specimens of tuberculous patients
EJMM-Egyptian Journal of Medical Microbiology [The]. 2012; 21 (1): 63-72
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| ID: emr-194244
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EMRO
Background: The emergence of drug resistant strains of Mycobacterium tuberculosis is of growing concern. Multi-drug resistance [MDR-TB] where the strain is resistant to both rifampicin [RIF] and isoniazid [INH], has been reported in all regions of the world. Early choice, and rapid determination of drug resistance can allow a customized approach to treatment early in the course of the disease and can potentially reduce morbidity, mortality and infectiousness. It would be helpful for low-resource countries to have simple and inexpensive tests which can rapidly detect resistance to RIF .The excellent performance of the BACTEC MGIT 960 for rapid detection of resistance to first- and second-line anti-TB drugs can be accomplished in days rather than weeks, although still constrained by high cost equipments and consumables. FASTPlaque-Response is a phage amplification-based test for detection of RIF resistance and has been developed for direct use on sputum specimens
Aim: The present study was undertaken to compare between BACTEC MGIT 960 method and FASTPlaque-Response method for the time, specificity and sensitivity determination of RIF susceptibility in sputum of both positive [+ve] and negative [-ve] AFB-smear of Mycobacterium tuberculosis patients
Results: In this study, a total of 60 specimens were collected and divided according to Z-N staining into two groups : group[1] which was Z.N [+ve]comprising 47 specimens ranged from+1 to +3 positivity, and group[2] which was Z.N -[-ve] comprising 13 specimens. The turnaround-time [TAT] of group[1] by BACTEC MGIT 960 ranged from 8 to 39.2 days with Mean +/- SD 13.9 +/- 3.4 days for positivity and ranged from 4 to 12.96 days with Mean +/- SD[8.02 +/- 1.98] days for susceptibility pattern, while in group[2] the TAT ranged from 8.2 to 41.75 days with Mean +/- SD[15 +/- 5.2] days for positivity and ranged from 4.04 to 13 days with Mean +/- SD [8. 6 +/- 2.2] days for susceptibility pattern ,In contrast to BACTEC MGIT960, FASTPlaque-Response susceptibility pattern was completed in just 48 hours. Susceptibility pattern of RIF by BACTEC MGIT 960 and FASTPlaque-Response showed the same results in 35 out of 60 specimens [58%] which were [26,6 and 3] Sensitive, resistant, and contaminant respectively, While the other 25 specimens [42%] showed discrepant results. In group [1]: 34 out of the 47 specimens [72 %] showed the same results by FASTPlaque- Response and BACTEC MGIT 960, while discrepancy occurred in the other 13 specimens [28 %], in which 12 specimens were RIF sensitive by the BACTEC MGIT 960 and showed different results by FASTPlaque- Response [6,2 and 4 were resistant ,contaminant and no growth respectively],while the 13th specimen which was resistant by BACTEC MGIT960 became sensitive with FASTPlaque- Response .In group[2] the results by the two methods were the same in only one out of 13 specimens [8 %], whereas the discrepancy was in the other 12 specimens [92 %] in which 8 specimens were sensitive with the BACTEC MGIT 960, 7of them showed no growth and the 8th was contaminant by FASTPlaque-Response, while 3 specimens were resistant by BACTEC MGIT 960, 2 of them were contaminant and 1 showed no growth by FASTPlaqueTB- Response, whereas, the 12th specimen was contaminant by BACTEC MGIT 960,but showed no growth with FASTPlaqueTB-Response . In group[1]; 4 out 47 specimens[8.5%] were contaminants and 4 specimens[8.5%] showed no growth by FASTPlaque- Response ,while,2 specimens[4.2%] were contaminants and no specimens showed no growth by BACTEC MGIT 960. In group[2];5 specimens out of 13 [38.5%] were contaminants and 8 specimens [61.5%] showed no growth by FASTPlaque- Response ,while,2 specimens[15.3%] were contaminants and no specimens showed no growth by BACTEC MGIT 960
Recommendation: Standardization of phage method to minimize the number of contaminated or incorrect results is necessary before this diagnostic tool can be implemented widely, and improvement needed to become highly sensitive and specific in that cases to become routinely used
Aim: The present study was undertaken to compare between BACTEC MGIT 960 method and FASTPlaque-Response method for the time, specificity and sensitivity determination of RIF susceptibility in sputum of both positive [+ve] and negative [-ve] AFB-smear of Mycobacterium tuberculosis patients
Results: In this study, a total of 60 specimens were collected and divided according to Z-N staining into two groups : group[1] which was Z.N [+ve]comprising 47 specimens ranged from+1 to +3 positivity, and group[2] which was Z.N -[-ve] comprising 13 specimens. The turnaround-time [TAT] of group[1] by BACTEC MGIT 960 ranged from 8 to 39.2 days with Mean +/- SD 13.9 +/- 3.4 days for positivity and ranged from 4 to 12.96 days with Mean +/- SD[8.02 +/- 1.98] days for susceptibility pattern, while in group[2] the TAT ranged from 8.2 to 41.75 days with Mean +/- SD[15 +/- 5.2] days for positivity and ranged from 4.04 to 13 days with Mean +/- SD [8. 6 +/- 2.2] days for susceptibility pattern ,In contrast to BACTEC MGIT960, FASTPlaque-Response susceptibility pattern was completed in just 48 hours. Susceptibility pattern of RIF by BACTEC MGIT 960 and FASTPlaque-Response showed the same results in 35 out of 60 specimens [58%] which were [26,6 and 3] Sensitive, resistant, and contaminant respectively, While the other 25 specimens [42%] showed discrepant results. In group [1]: 34 out of the 47 specimens [72 %] showed the same results by FASTPlaque- Response and BACTEC MGIT 960, while discrepancy occurred in the other 13 specimens [28 %], in which 12 specimens were RIF sensitive by the BACTEC MGIT 960 and showed different results by FASTPlaque- Response [6,2 and 4 were resistant ,contaminant and no growth respectively],while the 13th specimen which was resistant by BACTEC MGIT960 became sensitive with FASTPlaque- Response .In group[2] the results by the two methods were the same in only one out of 13 specimens [8 %], whereas the discrepancy was in the other 12 specimens [92 %] in which 8 specimens were sensitive with the BACTEC MGIT 960, 7of them showed no growth and the 8th was contaminant by FASTPlaque-Response, while 3 specimens were resistant by BACTEC MGIT 960, 2 of them were contaminant and 1 showed no growth by FASTPlaqueTB- Response, whereas, the 12th specimen was contaminant by BACTEC MGIT 960,but showed no growth with FASTPlaqueTB-Response . In group[1]; 4 out 47 specimens[8.5%] were contaminants and 4 specimens[8.5%] showed no growth by FASTPlaque- Response ,while,2 specimens[4.2%] were contaminants and no specimens showed no growth by BACTEC MGIT 960. In group[2];5 specimens out of 13 [38.5%] were contaminants and 8 specimens [61.5%] showed no growth by FASTPlaque- Response ,while,2 specimens[15.3%] were contaminants and no specimens showed no growth by BACTEC MGIT 960
Recommendation: Standardization of phage method to minimize the number of contaminated or incorrect results is necessary before this diagnostic tool can be implemented widely, and improvement needed to become highly sensitive and specific in that cases to become routinely used
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Índice:
IMEMR
Tipo de estudio:
Guideline
Idioma:
En
Revista:
Egypt. J. Med. Microbiol.
Año:
2012