Clinical Relevance of Nontuberculous Mycobacteria, Oman

Abstract

Little is known about the clinical relevance of nontuberculous mycobacteria (NTM) in the Arabian Peninsula. We assessed the prevalence and studied a random sample of isolates at a reference laboratory in Muscat, Oman. NTM cause disease in this region, and their prevalence has increased.N ontuberculous mycobacteria (NTM) are common inhabitants of the environment and have been cultured from water, soil, and animal sources worldwide. NTM are opportunistic pathogens, mostly affecting patients with preexisting pulmonary disease such as chronic obstructive pulmonary disease or tuberculosis (TB), or those with systemic impairment of immunity. The latter group includes those with HIV infection, those using immunosuppressive drugs, and those with leukemia (1).Because NTM are common in the environment and resistant to commonly used disinfectants, they can be present in nonsterile patient material such as sputum and contaminated medical equipment (bronchoscope washers or samples in the laboratory) and consequently cause pseudoinfection (1,2). To distinguish pseudoinfections from NTM disease and establish the clinical relevance of isolated NTM, the American Thoracic Society (ATS) has published diagnostic criteria (1).Studies on the clinical relevance of NTM have traditionally been restricted to western countries, where the incidence of TB is relatively low. More recently, research has been initiated in African and East Asian countries (1-5). There have been no recent reports on isolation and clinical relevance of NTM on the Arabian Peninsula. We analyzed a random sample of NTM isolated from clinical samples in Oman by using molecular techniques. Their clinical relevance was retrospectively analyzed by applying the updated ATS diagnostic criteria for NTM disease (1). The StudyPrevalence of NTM at the Central Public Health Laboratory (CPHL), the national TB reference laboratory of the Ministry of Health in Muscat, Oman, was assessed by using a laboratory database. The CPHL Institutional Review Board reviewed and approved this study. The CPHL received 5,488 samples submitted for Mycobacterium spp. culture during 2006-2007. Samples were subcultured in Lowenstein-Jensen medium and automated Mycobacterial Growth Indicator Tubes (MGIT960; Becton Dickinson, Franklin Lakes, NJ, USA) and incubated at 36°C. A total of 491 (9%) samples yielded positive cultures. M. tuberculosis complex bacteria were isolated from 445 (91%) samples, and NTM were isolated from 46 samples (9%). Most NTM were cultured from respiratory samples (sputum, n = 36, 78%; bronchial lavage, n = 2, 4%); the remainder were from lymph nodes (n = 3, 6%), urine (n = 2, 4%), or other sources (n = 3, 6%). The percentage of NTM increased from 7.6% (18/235) in 2006 to 10.9% (28/256) in 2007.Thirteen samples were randomly selected from all NTM isolated at CPHL during January 2006-September 2007. Selected NTM were subjected to molecular identification at the Dutch National Mycobacteria Reference Laboratory (National Institute for Public Health and the Environment, Bilthoven, ...

Species distribution of Non tuberculosis mycobacteria isolates from North of Iran

“…Comparing species abundance in this study is in agreement with the previous findings in Iran [18]. In Korea and U.S.A and in many parts of the world, Mycobacterium avium Complex (MAC) is the most common cause of infection among NTM [19,20]. In this study we have shown that among methods of species identification in mycobacterium using PRA on colony obtained from different mycobacterium with replication of 441 bp was faster and more precise in compare with biochemical methods.…”

Emergence of Clinically Relevant Non-Tuberculous Mycobacterial Infections in Saudi Arabia

“…Nonetheless this indicates an emergency event which seriously requires attention from concerned authorities. Neighboring countries also reported an increasing prevalence of NTM diseases recently [13], [16].…”

Epidemiology of Human Pulmonary Infection with Nontuberculous Mycobacteria

“…From various laboratories in Saudi Arabia, a sample of 95 patients with NTM isolation was identified during 2009–2010, including 73 patients with pulmonary isolation, 67% of whom (49/73) were judged to have pulmonary disease but clinical information was not detailed (62). In Oman, over 2006–2007, a random sample of 13 NTM isolates from the Central Public Health Laboratory in Muscat, was selected for case review (63). Eleven isolates were pulmonary, and ATS disease criteria were fulfilled in 63.6% (7/11).…”