Seleksi dan Evaluasi Mutu Beras Padi Gogo Adaptif Lahan Kering Masam

Perbaikan galur padi gogo dihadapkan pada adanya keragaman sifat fisik dan ekobiologis lahan kering, antara lain lahan kering masam. Alternatif pendekatan optimalisasi budidaya padi gogo di lahan kering masam adalah dengan pemilihan varietas yang adaptif. Tujuan penelitian ini untuk memperoleh sejumlah galur padi gogo yang memiliki keragaan dan hasil unggul di lahan kering masam, serta bermutu beras baik. Sebanyak 36 galur padi gogo dan empat varietas pembanding diseleksi di Kebun Percobaan Tamanbogo, Lampung pada musim hujan November 2017-Maret 2018. Pendugaan parameter genetik menunjukkan keragaman genetik luas berbanding lurus dengan nilai heritabilitas tinggi. Umur berbunga, umur panen, bobot 1,000 butir gabah dan hasil dapat dijadikan sebagai kriteria seleksi galur padi gogo di lahan kering masam. Berdasarkan kriteria seleksi tersebut terpilih empat galur, yaitu B15231-MR-10-1, B15053F-PWR-2, B14908C-MR-1-25-1-3 dan B15344B-TB-34. Galur-galur tersebut memiliki hasil gabah yang tidak berbeda nyata dengan varietas pembanding terbaik Inpago 8 (3.84 ton ha-1), rata-rata tahan terhadap blas daun (skor 1), sangat tahan terhadap blas leher (skor 0), dan agak toleran Al, . Keempat galur terpilih memiliki bentuk beras sedang dengan pengapuran sedikit sampai sedang (MMS-LMM), kadar amilosa 20-23% dengan tekstur nasi pulen-sedang. Satu galur terpilih, yaitu B15344B-TB-34 teridentifikasi sebagai galur beras merah. Kata kunci: kekeringan, keracunan aluminium, kriteria seleksi, mutu beras, penyakit blas

Whole-genome sequence analysis and comparisons between drug-resistance mutations and minimum inhibitory concentrations of Mycobacterium tuberculosis isolates causing M/XDR-TB

Drug resistance (DR) remains a major challenge for tuberculosis (TB) control. Whole-genome sequencing (WGS) provides the highest genetic resolution for genotypic drug-susceptibility tests (DST). We compared DST profiles of 60 Mycobacterium tuberculosis isolates which were drug resistant according to agar proportion tests (one poly DR-TB, 34 multidrug-resistant TB and 25 extensively drug-resistant TB). We additionally performed minimum inhibitory concentration (MIC) tests using Sensititre MYCOTBI plates (MYCOTB) and a WGS-based DST. Agreement between WGS-based DST and MYCOTB was high for all drugs except ethambutol (65%) and ethionamide (62%). Isolates harboring the -15 c/t inhA promoter mutation had a significantly lower MIC for isoniazid than did isolates with the katG Ser315Thr mutation (p < 0.001). Similar patterns were seen for ethambutol (embB Gly406Asp vs. embB Met306Ile), streptomycin (gid Gly73Ala vs. rpsL Lys43Arg), moxifloxacin (gyrA Ala90Val vs. gyrA Asp94Gly) and rifabutin (rpoB Asp435Phe/Tyr/Val vs. rpoB Ser450Leu). For genotypic heteroresistance, isolates with lower proportion of mapped read tended to has lower MIC of anti-TB drugs than those with higher proportion. These results emphasize the high applicability of WGS for determination of DR-TB and the association of particular mutations with MIC levels.

Molecular Detection of Mycobacterium tuberculosis in Oral Mucosa from Patients with Presumptive Tuberculosis

Tuberculosis (TB) diagnosis is increasingly based on the detection of Mycobacterium tuberculosis complex (MTBC) DNA in sputum using molecular diagnostic tests as the first test for diagnosis. However, sputum can be difficult to obtain in children, patients without productive cough, and the elderly and approaches testing non-sputum samples are needed. We evaluated whether TB can be detected from the oral mucosa of patients with TB. Adults with presumptive TB were examined using culture, Xpert MTB/RIF, smear microscopy and X-Rays. Oral mucosa swabs collected on PrimeStore-MTM, stored at room temperature if tested within 30 days or at −20 °C if examined at a later time. RT-PCR was performed to detect M. tuberculosis DNA. Eighty patients had bacteriologically-confirmed TB, 34 had bacteriologically-negative TB (negative tests but abnormal X-rays) and 152 were considered not to have TB (not TB). Oral swabs RT-PCR were positive in 29/80 (36.3%) bacteriologically-confirmed, 9/34 (26.5%) bacteriologically-negative and 29/152 (19.1%) not TB. The yield varied among samples stored for less and more than 30 days (p = 0.013) from 61% (11/18) and 29% (18/62) among bacteriologically confirmed, and 30.8% (4/13) and 23.8% (5/21) among bacteriologically-negative participants. Among not TB patients, the specificity was 80.9% (123/152), being 78.3% (18/23) among samples stored less than 30 days and 81.4% (105/129) among samples stored for more than 30 days (p = 0.46). The detection of M. tuberculosis in oral mucosa samples is feasible, but storage conditions may affect the yield.

Undiagnosed tuberculosis in patients with HIV infection who present with severe anaemia at a district hospital

Background: Tuberculosis (TB) is a major cause of severe anaemia in patients with human immunodeficiency virus (HIV) infection in South Africa. However, TB can be difficult to diagnose as it may be extra pulmonary and paucibacillary.Aim: The aim of this study was to investigate undiagnosed TB in patients with HIV infection and severe anaemia and to identify the optimal investigations for diagnosing TB.Setting: Mthatha General Hospital, a district hospital.Methods: The study was a case series.Results: Haemoglobin levels ranged from 3.6 g/dL to 7.9 g/dL, the mean CD4 count was 176 cells/μL and 80% of patients had a positive TB symptom screen. Forty-three (86%) patients had either clinical or bacteriologically proven TB of whom 33 had pulmonary TB, 34 had extra pulmonary TB and 24 had both types. The diagnostic yield for TB was: chest X-ray (CXR) 91%; ultrasound (US) abdomen pericardium and lower chest 62%; sputum Xpert MTB/RIF 35%; TB blood culture 21% and TB urine culture 15%. Blood and urine cultures did not identify any additional cases over those identified by CXR and US. The laboratory turnaround times were as follows: sputum Xpert, 1.6 days; blood culture, 20 days and urine culture, 28 days. CXR and US were done within one day of initial patient assessment.Conclusions: The majority of HIV patients with severe anaemia had TB disease, and extra pulmonary TB was as prevalent as pulmonary TB. CXR, US and sputum Xpert were the optimum tests for rapid diagnosis of TB. South African national TB/HIV guidelines should incorporate these specific tests to diagnose TB in patients with HIV and severe anaemia.