Many laboratories validate DST of the second-line drugs by BACTEC MGIT 960 system. The objective of this study is to evaluate the critical concentration and perform DST for the 2nd line drugs. We evaluated 193 clinical strains of M. tuberculosis isolated from patients in South Korea. Testing the critical concentration of six second-line drugs was performed by MGIT 960 and compared with L-J proportion method. The critical concentration was determined to establish the most one that gave the difference between drug resistance and susceptibility in MGIT960 system. Good agreement of the following concentrations was found: Concordance was 95% for 0.5？μg/mL of moxifloxacin; 93.6%, 1.0？μg/mL of levofloxacin; 97.5%, 2.5？μg/mL of kanamycin; 90.6%, 2.5？μg/mL of capreomycin; 86.2%, 5.0？μg/mL of ethionamide; and 90.8%, 2.0？μg/mL of -aminosalicylic acid. The critical concentrations of the four drugs, moxifloxacin, levofloxacin, kanamycin, and capreomycin, were concordant and reliable for testing 2nd line drug resistance. Further study of ethionamide and ρ-aminosalicylic acid is required. 1. Introduction Tuberculosis represents a major public health concern especially due to the increasing number of multidrug-resistant tuberculosis TB (MDR TB). Particularly in developing countries, extensively drug-resistant tuberculosis TB (XDR TB) continues to pose serious problem [1–5]. The increase in MDR/XDR TB rates prompts effective diagnostic methods so that appropriate treatments can be given to infected patients [6–8]. Many studies reported that MGIT 960 (Becton Dickinson Diagnostic System, Sparks, MD) provided reliable and rapid results in the detection and recovery of mycobacterium from clinical specimens and also the drug susceptibility testing (DST) of the TB isolates for the first line drugs isoniazid, rifampicin, ethambutol, streptomycin, and pyrazinamide [9, 10]. Recently, laboratories are facing great hindrances to provide DST for second-line drugs to ensure effective treatment of MDR/XDR TB by using MGIT 960 system [11–16]. However, in most of these studies, the tested numbers of second-line anti-TB drug were limited and the critical concentrations ranges of the second-line drugs were also discordant [11–13]. Despite the recommendation by WHO in 2008 for the use of liquid media for the second-line DST using MGIT 960, it is still unreliable due to the difficulty in determining the critical concentration [16]. It is not easy to calibrate newly developed DST methods using altered conditions. In vitro results of DST to second-line drugs were affected by criteria for
References
[1]
M. A. Aziz, A. Wright, A. Laszlo et al., “Epidemiology of antituberculosis drug resistance (the Global Project on Anti-tuberculosis Drug Resistance Surveillance): an updated analysis,” Lancet, vol. 368, no. 9553, pp. 2142–2154, 2006.
[2]
R. Banerjee, G. F. Schecter, J. Flood, and T. C. Porco, “Extensively drug-resistant tuberculosis: new strains, new challenges,” Expert Review of Anti-Infective Therapy, vol. 6, no. 5, pp. 713–724, 2008.
[3]
N. R. Gandhi, A. Moll, A. W. Sturm et al., “Extensively drug-resistant tuberculosis as a cause of death in patients co-infected with tuberculosis and HIV in a rural area of South Africa,” Lancet, vol. 368, no. 9547, pp. 1575–1580, 2006.
[4]
M. C. Raviglione and I. M. Smith, “XDR tuberculosis—implications for Global Public Health,” New England Journal of Medicine, vol. 356, no. 7, pp. 656–659, 2007.
[5]
N. S. Shah, A. Wright, G. H. Bai, et al., “Worldwide emergence of extensively drug-resistant tuberculosis,” Emerging Infectious Diseases, vol. 13, no. 3, pp. 380–387, 2007.
[6]
A. Martin, J. C. Palomino, and F. Portaels, “Rapid detection of ofloxacin resistance in Mycobacterium tuberculosis by two low-cost colorimetric methods: resazurin and nitrate reductase assays,” Journal of Clinical Microbiology, vol. 43, no. 4, pp. 1612–1616, 2005.
[7]
N. Morcillo, B. Di Giulio, B. Testani, M. Pontino, C. Chirico, and A. Dolmann, “A microplate indicator-based method for determining the susceptibility of multidrug-resistant Mycobacterium tuberculosis to antimicrobial agents,” International Journal of Tuberculosis and Lung Disease, vol. 8, no. 2, pp. 253–259, 2004.
[8]
T. Prammananan, W. Arjratanakool, A. Chaiprasert et al., “Second-line drug susceptibilities of Thai multidrug-resistant Mycobacterium tuberculosis isolates,” International Journal of Tuberculosis and Lung Disease, vol. 9, no. 2, pp. 216–219, 2005.
[9]
P. Bemer, T. Bodmer, J. Munzinger, M. Perrin, V. Vincent, and H. Drugeon, “Multicenter evaluation of the MB/BACT system for susceptibility Testing of Mycobacterium tuberculosis,” Journal of Clinical Microbiology, vol. 42, no. 3, pp. 1030–1034, 2004.
[10]
L. Heifets, T. Linder, T. Sanchez, D. Spencer, and J. Brennan, “Two liquid medium systems, mycobacteria growth indicator tube and MB redox tube, for Mycobacterium tuberculosis isolation from sputum specimens,” Journal of Clinical Microbiology, vol. 38, no. 3, pp. 1227–1230, 2000.
[11]
I. Bastian, L. Rigouts, J. C. Palomino, and F. Portaels, “Kanamycin susceptibility testing of Mycobacterium tuberculosis using Mycobacterium growth indicator tube and a colorimetric method,” Antimicrobial Agents and Chemotherapy, vol. 45, no. 6, pp. 1934–1936, 2001.
[12]
A. Krüüner, M. D. Yates, and F. A. Drobniewski, “Evaluation of MGIT 960-based antimicrobial testing and determination of critical concentrations of first- and second-line antimicrobial drugs with drug-resistant clinical strains of Mycobacterium tuberculosis,” Journal of Clinical Microbiology, vol. 44, no. 3, pp. 811–818, 2006.
[13]
M. Palaci, S. Y. M. Ueki, D. N. Sato, M. Alice da Silva Telles, M. Curcio, and E. A. M. Silva, “Evaluation of mycobacteria growth indicator tube for recovery and drug susceptibility testing of Mycobacterium tuberculosis isolates from respiratory specimens,” Journal of Clinical Microbiology, vol. 34, no. 3, pp. 762–764, 1996.
[14]
S. Rüsch-Gerdes, G. E. Pfyffer, M. Casal, M. Chadwick, and S. Siddiqi, “Multicenter laboratory validation of the BACTEC MGIT 960 technique for testing susceptibilities of Mycobacterium tuberculosis to classical second-line drugs and newer antimicrobials,” Journal of Clinical Microbiology, vol. 44, no. 3, pp. 688–692, 2006.
[15]
M. Sharma, L. Thibert, P. Chedore, et al., “Canadian multicenter laboratory study for standardized second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis,” Journal of Clinical Microbiology, vol. 49, no. 12, pp. 4112–4116, 2011.
[16]
World Health Organization, “Policy guidance on drug-susceptibility testing (DST) of 2nd antituberculosis drug,” WHO/HTM/TB/2008.392. Geneva, Switzerland, 2008.
[17]
K. M. Kam, A. Sloutsky, C. W. Yip et al., “Determination of critical concentrations of second-line anti-tuberculosis drugs with clinical and microbiological relevance,” International Journal of Tuberculosis and Lung Disease, vol. 14, no. 3, pp. 282–288, 2010.
[18]
G. Canetti, W. Fox, A. Khomenko et al., “Advances in techniques of testing mycobacterial drug sensitivity, and the use of sensitivity tests in tuberculosis control programmes,” Bulletin of the World Health Organization, vol. 41, no. 1, pp. 21–43, 1969.
[19]
C. Rodrigues, J. Jani, S. Shenai, P. Thakkar, S. Siddiqi, and A. Mehta, “Drug susceptibility testing of Mycobacterium tuberculosis against second-line drugs using the Bactec MGIT 960 System,” International Journal of Tuberculosis and Lung Disease, vol. 12, no. 12, pp. 1449–1455, 2008.
[20]
J. Van Ingen, S. Simons, R. De Zwaan et al., “Comparative study on genotypic and phenotypic second-line drug resistance testing of Mycobacterium tuberculosis complex isolates,” Journal of Clinical Microbiology, vol. 48, no. 8, pp. 2749–2753, 2010.
[21]
C. Piersimoni, C. Lacchini, V. Penati et al., “Validation of the agar proportion and 2 liquid systems for testing the susceptibility of Mycobacterium tuberculosis to moxifloxacin,” Diagnostic Microbiology and Infectious Disease, vol. 57, no. 3, pp. 283–287, 2007.
[22]
S. Y. G. Lin, E. Desmond, D. Bonato, W. Gross, and S. Siddiqi, “Multicenter evaluation of Bactec MGIT 960 system for second-line drug susceptibility testing of Mycobacterium tuberculosis complex,” Journal of Clinical Microbiology, vol. 47, no. 11, pp. 3630–3634, 2009.
[23]
C. A. Sanders, R. R. Nieda, and E. P. Desmond, “Validation of the use of middlebrook 7H10 agar, BACTEC MGIT 960, and BACTEC 460 12B media for testing the susceptibility of Mycobacterium tuberculosis to levofloxacin,” Journal of Clinical Microbiology, vol. 42, no. 11, pp. 5225–5228, 2004.
[24]
F. Giannoni, E. Iona, F. Sementilli et al., “Evaluation of a new line probe assay for rapid identification of gyrA mutations in Mycobacterium tuberculosis,” Antimicrobial Agents and Chemotherapy, vol. 49, no. 7, pp. 2928–2933, 2005.
[25]
T. S. Huang, S. S. J. Lee, H. Z. Tu et al., “Use of MGIT 960 for rapid quantitative measurement of the susceptibility of Mycobacterium tuberculosis complex to ciprofloxacin and ethionamide,” Journal of Antimicrobial Chemotherapy, vol. 53, no. 4, pp. 600–603, 2004.
[26]
S. Feuerriegel, H. S. Cox, N. Zarkua et al., “Sequence analyses of just four genes to detect extensively drug-resistant Mycobacterium tuberculosis strains in multidrug-resistant tuberculosis patients undergoing treatment,” Antimicrobial Agents and Chemotherapy, vol. 53, no. 8, pp. 3353–3356, 2009.
[27]
B. Springer, K. Lucke, R. Calligaris-Maibach, C. Ritter, and E. C. B？ttger, “Quantitative drug susceptibility testing of Mycobacterium tuberculosis by use of MGIT 960 and EpiCenter instrumentation,” Journal of Clinical Microbiology, vol. 47, no. 6, pp. 1773–1780, 2009.
[28]
M. J. Ruiz-Serrano, L. Alcala, L. Martinez et al., “In vitro activities of six fluoroquinolones against 250 clinical isolates of Mycobacterium tuberculosis susceptible or resistant to first-line antituberculosis drugs,” Antimicrobial Agents and Chemotherapy, vol. 44, no. 9, pp. 2567–2568, 2000.
[29]
D. A. Mitchison, “Drug resistance in tuberculosis,” European Respiratory Journal, vol. 25, no. 2, pp. 376–379, 2005.
