Overview of Non Tuberculosis Mycobacterial Lung Diseases

Nontuberculosis mycobacteria (NTM) are ubiquitous in nature and opportunistically infect different animals, including humans. Currently, NTM is emerging as an important cause of pulmonary infection among both immunocompromised and immunocompetent persons worldwide. The clinical relevance of pulmonary NTM varies among species while showing geographical heterogeneity in distribution as well as pathogenicity. The outcome of the respiratory NTM disease is a consequence of a complex interplay between microbial factors and host susceptibility. Furthermore, HIV infection, cystic fibrosis, cancer, underlying chronic lung disease and history of tuberculosis (TB) may be associated as risk factors for active nontuberculosis pulmonary diseases (NTMPD). The diagnosis of NTMPD requires the presence of symptoms, radiographic evidences, microscopic observations and definitive laboratory diagnostics. Lung infections resulted from a clinically significant NTM species should be treated with appropriate antimicrobial regimen

Dynamics of Mycobacterium tuberculosis Lineages in Oman, 2009 to 2018

Study aim. Effective Tuberculosis (TB) control measures in Oman have reduced the annual incidence of tuberculosis cases by 92% between 1981 and 2016. However, the current incidence remains above the program control target of <1 TB case per 100,000 population. This has been partly attributed to a high influx of migrants from countries with high TB burdens. The present study aimed to elucidate Mycobacterium tuberculosis infection dynamics among nationals and foreigners over a period of 10 years. Methods. The study examined TB cases reported between 2009 and 2018 and examined the spatial heterogeneity of TB cases and the distribution of M. tuberculosis genotypes defined by spoligotypes and MIRU-VNTR among Omanis and foreigners. Results. A total of 484 spoligoprofiles were detected among the examined isolates (n = 1295). These include 943 (72.8%) clustered and 352 (27.2%) unique isolates. Diverse M. tuberculosis lineages exist in all provinces in Oman, with most lineages shared between Omanis and foreigners. The most frequent spoligotypes were found to belong to EAI (318, 30.9%), CAS (310, 30.1%), T (154, 14.9%), and Beijing (88, 8.5%) lineages. However, the frequencies of these lineages differed between Omanis and foreigners. Of the clustered strains, 192 MTB isolates were further analysed via MIRU-VNTR. Each isolate exhibited a unique MIRU-VNTR profile, indicative of absence of ongoing transmission. Conclusions. TB incidence exhibits spatial heterogeneity across Oman, with high levels of diversity of M. tuberculosis lineages among Omanis and foreigners and sub-lineages shared between the two groups. However, MIRU-VNTR analysis ruled out ongoing transmission

The manual mycobacteria growth indicator tube and the nitrate reductase assay for the rapid detection of rifampicin resistance of <it>M. Tuberculosis</it> in low resource settings

Abstract Background Tuberculosis (TB) is a disease of poverty that contributes significantly to ill-health in developing countries. Drug resistant TB is a major challenge to disease control. Early diagnosis and rapid determination of drug sensitivity is of paramount importance in eradication of TB. Although automated liquid culture based methods are available for rapid detection of drug resistance, the high cost of these tests prevent them from being used routinely in low resource settings. This study compares two phenotypic methods, the manual Mycobacteria Growth Indicator Tube (MGIT) and the Nitrate Reductase Assay (NRA) in liquid medium, with the agar proportion method (APM), the gold standard for susceptibility testing of Mycobacterium tuberculosis. Methodology Fourteen day old M. tuberculosis strains (n=373) grown on solid media were used for drug susceptibility testing by APM, NRA and the manual MGIT method. Rifampicin free and rifampicin incorporated (final concentration, 1 μg/ml) media were inoculated with the recommended concentrations of mycobacterial suspensions and incubated at 37°C in 5% CO2. In the APM, the proportion of colonies in the drug containing medium was determined. In the NRA, the colour change in the medium was compared with a standard colour series after day 6 and day 12 of incubation. Growth in the MGIT was detected using the manual MGIT reader from day 2 onwards. The 2 methods were compared with the gold standard, APM to determine sensitivity and specificity and agreement between the methods was calculated using kappa statistics. Results Thirty one (31) rifampicin resistant isolates were identified. When compared with the APM, the sensitivity of detection of rifampicin resistance was 85% for the NRA and 93% for the manual MGIT and the specificity was 99% and 100% respectively. Both assays, NRA (κ=0.86) and manual MGIT method (κ= 0.94) were in excellent agreement with the APM. The mean turnaround time for manual MGIT method and NRA were 08 days and 10 days respectively. Conclusion The NRA in liquid medium and manual MGIT are useful alternatives to APM for drug susceptibility testing of M. tuberculosis in low resource settings.</p

Mycobacterium farcinogenes osteomyelitis of the proximal tibia: A case report

Non-tuberculous mycobacteria (NTM) are an unusual cause of osteomyelitis. Mycobacterium farcinogenes is an uncommon cause of human disease. We describe here the first case of M. farcinogenes osteomyelitis in a 49-year-old man who underwent left knee anterior cruciate ligament and medial meniscal repair which was complicated by recurrent septic arthritis and surgical site infection. As a consequence, he underwent multiple surgical debridements. Ultimately, left proximal tibial osteomyelitis was diagnosed and M. farcinogenes was recovered from the tissue biopsy culture. Clinical improvement was achieved following surgical removal of the prosthesis along with prolonged combination antimicrobial therapy

Genomic and geospatial epidemiology of Mycobacterium tuberculosis in Oman: first national insight using whole genome sequencing

ABSTRACT: Objectives: Mycobacterium tuberculosis (MTB) is a global public health issue. Although Oman reduced the burden of tuberculosis (TB) by 85% in under 25 years, the annual incidence rate remains stagnant. Whole genome sequencing (WGS) is used to investigate the transmission dynamics of MTB complex. This study aimed to resolve traditional genotype clusters and exploring the geospatial distribution to understand the epidemiology of TB in Oman. Methods: Confirmed cases with spoligotyping clusters were randomly selected. WGS of 70 isolates were selected for final analysis. Correlation of epidemiological and geospatial data was conducted. Results: A total of 233 cases were registered in 2021; 169 had confirmed growth, with an incidence rate of 5.2/100,000 population for 2021. A total of 70 genomes were analyzed, and five large clusters and three medium clusters were identified. The lineages L1, L2, L3, and L4 and several sublineages belonging to the Indo-Oceanic family and East African Indian family were identified as predominant in Oman. There were no multidrug-resistant cases identified. Conclusion: There is a considerable genetic variation among the strains in Oman. This predominance could be linked with the high percentage of non-national population, which represents different countries and frequent traveling to high TB burden countries. WGS combined with geospatial investigations of MTB are required to better understand the disease transmission in Oman, which will support TB elimination efforts