Comparison of Line Probe Assay (LPA) and Mycobacterium Growth Indicator Tubes (MGIT) Assay for Second-line TB Drug Susceptibility Testing

BACKGROUND: Tuberculosis (TB) infection is one of the most prominent health issues in the world, including in Indonesia. TB is evolving into multidrug-resistant tuberculosis (MDR-TB) and requiring second-line TB drugs. Mycobacterium growth indicator tube (MGIT) is the gold standard for susceptibility testing of second-line TB drugs. Alternatively, line probe assay (LPA), which detects genes resistant to second-line TB drugs, takes a shorter time to run. This study aims to compare MGIT and LPA's ability to detect TB resistance to second-line TB drugs and observe mutation patterns of genes encoding second-line TB drugs.METHODS: This was an observational analytic study, using cross-sectional method. The data were acquired from the MDR-TB clinic’s medical records at the Dr. Hasan Sadikin Hospital from September to December 2019. LPA and MGIT test were conducted at the Health Laboratory Hall of West Java Province, then tested using Kolmogorov-Smirnov and chi-square statistic.RESULTS: From 121 subjects, 113 people were not resistant to the second-line TB drugs, which was examined using both LPA and MGIT (93.4%), p=0.991. Mutations were found in gyrA and rrs gene. There was no significant difference between the proportion of subjects resistant to the second-line of TB drugs tested using LPA and MGIT.CONCLUSION: LPA is an alternative method to MGIT because it requires a shorter time and reduces the risk of exposure that will improve MDR-TB patients management.KEYWORDS: line probe assay (LPA), multidrug-resistant TB, mycobacterium growth indicator tube (MGIT), second-line TB drugs

Spoligotyping, Resistensi Mycobacterium tuberculosis terhadap obat TB dan Faktor Risiko Penularan Tuberkulosis Paru di Kota Jayapura

Identification of the Mycobacterium tuberculosis strain found in pulmonary tuberculosis patients in Jayapura using Spolygotyping was carried out Patients with pulmonary tuberculosis are taken as an index case. Sputum samples were taken to be diagnosed with Acid Fast Staining and to culture M. tuberculosis bacteria using Lowensten Jansen solid media, Ogawa solid media and Mycobacterium Growth Indicator Tube liquid media. The patient's home visit was conducted to determine the environmental conditions of the patient's residence, interview the close contacts and test the bacterial infection M. tuberculosis in close contact cases using the Mantoux test. A thorax radiology of close contacts was carried out in the hospital's radiology unit. The results of spolygotyping showed 8%sputum samples M. tuberculosis of Beijing strain, while the rest are M. tuberculosis non Beijing strains. Among the 46 of Non-Beijing strains, the type U (likely S) is most transmitted by tuberculosis patients to their close contacts, which is as much as 6%. This study confirms the factors that influence tuberculosis transmission are the sleeping location of close contacts with the patients, the frequency of meetings that occur at least once or more in a day, density of house occupants and the presence of clinical symptoms of TB. Drugs Resistance Susceptibility test results showed that 12 patients were resistance to TB drugs and one of them was MDR TB from strain LAMP. Key words : tuberculosis transmission, Spolygotyping, tuberculosis, Jayapura, drugs resistance Abstrak Identifikasi galur Mycobacterium tuberculosis yang ditemukan pada penderita tuberculosis paru di Jayapura telah dilakukan dengan menggunakan Spoligotyping Penderita tuberkulosis paru diambil sebagai kasus indeks. Sampel sputum juga diambil untuk didiagnosis dengan pengecatan Basil Tahan Asam dan kultur bakteri M.tuberculosis yang dilakukan pada media padat Lowensten Jansen, media padat Ogawa serta media cair Mycobacterium Growth Indicator Tube. Ekstraksi DNA dilakukan pada koloni Mycobacterium tuberculosis untuk dilakukan analisis spoligotyping. Kunjungan rumah pasien dilakukan untuk mengetahui kondisi lingkungan tempat tinggal pasien, mewawancara kontak kasus dan melakukan skrining infeksi bakteri M.tuberkulosis pada kasus kontak menggunakan tes Mantoux. Foto dada pada kontak kasus selanjutnya dilakukan di unit radiologi rumah sakit. Hasil spoligotyping menunjukkan 8% (4/50) sampel sputum penderita tuberkulosis adalah M.tuberculosis galur Beijing, sedangkan sisanya adalah M.tuberculosis galur Non Beijing. Dari 46 galur Non-Beijing, tipe U (likely S) paling banyak ditransmisikan oleh penderita tuberculosis pada kontaknya yaitu sebanyak 6% (3/50). Penelitian ini mengkonfirmasi faktor-faktor yang mempengaruhi transmisi tuberkulosis meliputi lokasi tidur kontak kasus yang serumah dengan penderita, frekuensi pertemuan yang terjadi sedikitnya sekali atau lebih dalam sehari, kondisi rumah padat penghuni dan adanya gejala klinis TB. Hasil uji resistensi menunjukkan 12 pasien mengalami resistensi terhadap OAT dan 1 diantaranya adalah MDR TB dari strain LAMP. Kata kunci : Transmisi, Splygotyping, Mycobacterium tuberculosis, tuberkulosis, Jayapura, resistensi

Failure of BACTEC™ MGIT 960™ to detect Mycobacterium tuberculosis complex within a 42-day incubation period

For the optimal recovery of Mycobacterium tuberculosis from the BACTEC™ Mycobacterium Growth Indicator Tube 960™ system, an incubation period of 42–56 days is recommended by the manufacturer. Due to logistical reasons, it is common practice to follow an incubation period of 42 days. We undertook a retrospective study to document positive Mycobacterium Growth Indicator Tube cultures beyond the 42-day incubation period. In total, 98/110 (89%) were positive for M. tuberculosis complex. This alerted us to M. tuberculosis growth detection failure at 42 days.