Incidence Of Mycobacterium Tuberculosis Research Articles

Tuberculosis and Nontuberculous Mycobacterial Infections in Patients with Spondyloarthritis: A Population-Based Study.

Background and Objectives: Tuberculosis is caused by Mycobacterium tuberculosis (MTB), while nontuberculous mycobacteria (NTM) encompass a group of mycobacterial species that are distinct from the MTB complex and leprae. Spondyloarthritis (SpA) is a group of chronic inflammatory diseases with shared clinical characteristics and is treated with biological agents; however, their use may elevate the risk of MTB and NTM infections. This study aimed to compare the incidence and risk of MTB and NTM infections in patients with SpA, including ankylosing spondylitis (AS) and psoriatic arthritis (PsA), using a population-based approach. Materials and Methods: This study included 2333 patients with SpA and 9332 age- and sex-matched controls from the Korea National Health Insurance Service-National Sample Cohort database from 2002 to 2019. The patients were identified using the International Classification of Diseases-10 codes for AS, PsA, MTB, and NTM. Results: The results showed that a negligible percentage of patients with SpA developed NTM (0.002%) and MTB (0.016%), with no significant difference in the incidence rate ratio (IRR) compared to controls. Among patients with SpA treated with biologics, the IRRs for NTM and MTB were 5.66 and 3.069, respectively; however, these were not statistically significant. No cases of NTM or MTB infection were reported in female patients with SpA treated with biologics. In both the SpA patient group and the control group, the incidence of MTB was higher in individuals over 60 years old compared to those under 60 years old. Cox proportional hazard analysis revealed a significant adjusted hazard ratio of 1.479 for MTB in patients with SpA after adjusting for age, sex, smoking history, insurance level, and comorbidities. However, this significance was not maintained when biological therapy was further adjusted. Conclusions: Our study indicated that the risks of NTM and MTB infection are not elevated in patients with SpA. Although biological use may potentially increase the risk of MTB infection, it does not lead to a significant increase in incidence rates. Proactive screening for latent tuberculosis and adequate prophylaxis using biologics can effectively manage the risk of NTM and MTB infections.

Modified gold nanoparticle colorimetric probe-based biosensor for direct and rapid detection of Mycobacterium tuberculosis in sputum specimens

The incidence of Mycobacterium tuberculosis (MTB) is increasing due to lack of appropriate diagnostic and therapeutic methods. Therefore, early and accurate detection of this bacteria plays a significant role in controlling tuberculosis. This study aimed to design, develop, and implement a direct and rapid detection method of MTB using modified gold nanoparticle (AuNP) colorimetric probe-based biosensor in sputum specimens. Spherical AuNPs were synthesized by the citrate reduction method and were functionalized using thiol-modified oligonucleotides (AuNP-biosensor). AuNP-biosensor and IS6110 PCR were compared to the gold standard in terms of analytical and clinical sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic odds ratio (DOR), and accuracy in 52 clinical specimens. Gold standard was defined as a positive result in concentrated sputum smear microscopy (SSM), culture, or Xpert MTB/RIF.The AuNP-biosensor had 100% sensitivity and specificity for detection of total sputum DNA in less than 15min with ready-to-use AuNP-biosensor. PPV, NPV, DOR and accuracy of this method were 100%, 100%, 2325 and 100%, respectively. Considering the promising results of the diagnostic value indices of the AuNP-biosensor, the designed method is an affordable, rapid, reliable, and cost-beneficial way for direct detection of MTB in sputum specimens.

Utility of GeneXpert Mycobacterium Tuberculosis/Rifampicin Assay in Smear-Negative Pulmonary Tuberculosis

Background: Tuberculosis (TB) remains one of the world's deadliest communicable diseases. An alarming rise in the incidence of Mycobacterium tuberculosis (MTB) has prompted the need for rapid diagnostic techniques. Despite low sensitivity in MTB detection, sputum microscopy remains the main diagnostic method, especially in resource-limited settings. Mycobacterial culture is the gold standard method for TB diagnosis; however, the use in clinical practice is limited due to longer time, biosafety requirements, and high cost. In December 2010, the World Health Organization (WHO) 1st endorsed the usage of Xpert MTB/rifampicin (RIF) assay. The WHO recommends that GeneXpert test could be used as a follow on test to microscopy, especially in smear-negative specimens. Objectives: To assess percentage of Tuberculosis cases and Multi Drug Resistant (MDR) case detection at diagnosis using Xpert MTB/RIF assay in smear-negative pulmonary cases. Materials and Methodology: Detailed relevant clinical history and examination were carried out for 105 pulmonary TB suspect patients. Sputum acid-fast bacilli smear two samples and human immunodeficiency virus status were checked under RNTCP; chest X-ray PA view was done. Smear-negative patients were subjected to bronchoscopy and bronchoalveolar lavage (BAL)/bronchial washing. BAL/Bronchial washing was tested for GeneXpert. Interpretation and Conclusion: MTB was detected in 21 (20%) samples out of 105 samples and RIF resistance was detected in 1 (1%) sample. Most common chest x-ray abnormalities were cavity (33.3%) and consolidation (33.3%). 8 cases (38.1%) among Gene xpert positives had past history of Tuberculosis. Comorbidities were found in 5 cases (23.8%) among Gene Xpert positives. The present study concludes that using standard clinical assessment for selection, five patients need to be tested to detect one case of smear-negative TB. Smear-negative patients could benefit from Xpert, particularly in areas where no culture is available.

Rifampicin-Resistant Mycobacterium tuberculosis Among Patients with Presumptive Tuberculosis in Addis Ababa, Ethiopia.

BackgroundDrug-resistant tuberculosis remains a major public health threat complicating tuberculosis control programs globally. Data on rifampicin resistance (RR), which is a surrogate marker for multidrug resistance, are limited among Ethiopian tuberculosis patients. This study aimed to determine the magnitude of rifampicin-resistant Mycobacterium tuberculosis (RR-MTB) among presumptive tuberculosis patients attending St. Peter Tuberculosis Specialized Hospital, Addis Ababa, Ethiopia.Patients and MethodsA retrospective cross-sectional study was conducted at St. Peter Tuberculosis Specialized Hospital from January 2016 to December 2018. After checking completeness of the necessary information, data of tuberculosis-presumptive cases who underwent Gene Xpert® testing were collected from medical records using a data-extraction format prepared for this study purpose. Data were double entered and analyzed using SPSS version 20 statistical software.ResultsA total of 12,685 presumptive tuberculosis patients were included; of whom 54.5% were males and the mean age of the study participants was 40.3±18.7 years. Mycobacterium tuberculosis (MTB) was detected in 1714 participants (13.5%). Of these MTB cases, 169 cases (9.8%) were confirmed to have RR-MTB. Prevalence of MTB was relatively higher among males (15.1%, P=0.78); whereas RR-MTB was higher among females (10.3%, P=0.81). The incidence of MTB and RR-MTB was significantly associated with treatment history (P=0.042 and P=0.025), respectively. HIV infection has significantly associated with incidence of RR-MTB (P=0.032), but not with MTB (P˃0.05). Prevalence of MTB and RR-MTB had a declining trend through time, being 16.7% and 12.9%, 12.8% and 9.1%, and 12.2% and 7.9% in 2016, 2017 and 2018, respectively.ConclusionThis study showed a decreasing trend of both MTB and RR-MTB from 2016 to 2018 in an MTB, MDR-MTB, and TB/HIV co-infection high-burden setting, Addis Ababa, Ethiopia. Occurrence of MTB and RR-MTB was associated with treatment history. Therefore, improvement in treatment adherence of identified cases would be helpful to prevent emergence or re-emergence of MTB and RR-MTB cases.

TB AND SOLID ORGAN TRANSPLANT: THINK OUTSIDE OF THE LUNGS

SESSION TITLE: Chest Infections 1 SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTON: The incidence of Mycobacterium Tuberculosis (TB) is significantly higher among solid organ transplant recipients. Diagnosis requires a high level of suspicion, as transplant patients may present atypically or with extrapulmonary disease. Management can be difficult due to interactions between TB medications and immunosuppressive drugs. CASE PRESENTATION: A 66-year old Chinese man with a history of treated latent TB and cadaveric kidney transplant was admitted to the hospital with weakness, fever, blurred vision, and worsening left knee pain and swelling. Over the prior two months, he had presented to multiple urgent care centers with the same joint symptoms, for which he was treated with non-steroidal anti-inflammatory drugs. Knee X-ray had shown mild swelling. Patient’s immunosuppressive regimen included prednisone, mycophenylate mofetil, and tacrolimus. On admission, there was a mild leukocytosis, mildly elevated alkaline phosphatase level, and hypercalcemia. Computerized tomography of the chest (figure 1), abdomen and pelvis revealed diffuse pulmonary micro-nodules, gastric thickening, and a left knee effusion with possible osteomyelitis (figure 2). Magnetic resolution imaging of the brain showed evidence of optic neuritis (figure 3). Synovial fluid contained 12,300 white blood cells, with 87% neutrophils. Cerebrospinal fluid analysis was unremarkable. Smears and cultures for acid fast bacilli (AFB) were positive in samples from synovial fluid, sputum, stool, urine and blood. Treatment with rifabutin, isoniazid, ethambutol, pyrazinamide, and levofloxacin was initiated. Mycophenylate mofetil was discontinued, and treatment with tacrolimus was continued with close monitoring of drug levels. Drug levels for isoniazid and rifabutin were sub-therapeutic, and rifabutin and levofloxacin were then administered intravenously and amikacin added. Fevers resolved, visual acuity returned to normal, knee swelling improved, and tacrolimus levels remained in the therapeutic range. DISCUSSION: TB may present as monoarticular swelling of insidious onset, resulting in prolonged treatment delays. Solid organ transplant recipients with a history of latent TB infection or immigration from TB endemic areas are at increased risk, especially in the first year after transplant. Diagnosis requires prompt arthocentesis, which reveals a neutrophil-predominant effusion and AFB. Monitoring and adjustment of TB and immunosuppressive drug levels are critical. CONCLUSIONS: We present a case of disseminated tuberculosis presenting as monoarticular arthritis in a solid organ transplant patient. A high index of suspicion is essential to avoid treatment delays. Reference #1: Aguado JM, Torre-Cisneros J, Fortun J, Benito N, Meije Y, Doblas A, and Munoz P. Tuberculosis in solid-organ transplant recipients: consensus statement of the group for the study of infection in transplant recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology. Clin Infect Dis. 2009;48(9):1276-84. Reference #2: Sundaram M, Adhikary SD, John GT, Kekre NS. Tuberculosis in renal transplant recipients. Indian J Urol. 2008;24(3):396-400. DISCLOSURES: Scientific Medical Advisor relationship with Cohero Health Please note: $1-$1000 Added 03/05/2018 by Caralee Caplan-Shaw, source=Web Response, value=Ownership interestRemoved 03/05/2018 by Caralee Caplan-Shaw, source=Web Response Scientific Medical Advisor relationship with Cohero Health Please note: $1-$1000 Added 03/05/2018 by Caralee Caplan-Shaw, source=Web Response, value=shares No relevant relationships by Assad Oskuei, source=Web Response

Molecular Detection of Mycobacterium tuberculosis (MTB) and Rifampicin Resistant Strain among Subjects Accessing Health Care at Federal Medical Centre, Yenegoa, Bayelsa State; Nigeria

Background: An increasing global incidence of Mycobacterium Tuberculosis (MTB), and emergence of drug resistant strains of MTB, have critically promoted the urgent need to explore better effective methods that can rapidly detect MTB, and identify drug-resistant cases as recommended by World Health Organization report of 2008. Globally, multi-drug-resistant strains of MTB are increasingly becoming a huge public health issue, which has adversely affected the health care delivery of patients, especially in developing communities with limited functioning health care facility. Nonetheless, the aim and focus of the study is to evaluate the trend of rifampicin resistance strains of MTB among patients accessing care at the University of Port Harcourt Teaching Hospital. Methods: This observational cross-sectional study which utilized stratified proportionate random technique, was designed to evaluate the molecular detection, as well as the prevalence of MTB and multidrug resistant TB specifically RIF among the studied population. Results: The study population were 204 subjects recruited randomly, with a mean age of 37.23 ± 16.68 years and were categorized based on sex, 93 (45.6%) males and 111 (54.4%) females respectively. The MTB detected were 21 (10.3%) while 183 (89.7%) were negative. Also, drug resistant test was performed specifically for RIF to ascertain RIF resistant strain and the non-RIF resistant strains; only 6 (2.9%) were resistant to RIF while 197 (96.6%) were not resistant to RIF. Correlation analysis of MTB detected between sex, age and resistant to RIF showed nonsignificant association (p>0.05). The prevalence rates include: 2.9% and 7.4% for RIF Resistance and Non-RIF resistance respectively. Chi square result reported about 90% non-significance and 10% significance which occurred in the counts between RIF resistant and MTB detected (p<0.05). Conclusion: The use of dependable molecular detection of MTB method has been able to provide strong epidemiological impetus for an enhanced MTB diagnosis and management to be encouraged and should be sustained, especially in resources limited regions like Nigeria, with massive challenges of prompt and accurate diagnosis of the infection. However, it is strongly believed that continuous leveraging on the potency of the molecular diagnostic approach will help to uncover the rifampicin resistance strains, which obviously would have been a huge challenge with the routine microscopic smear method.

Incidence of Mycobacterium tuberculosis in Patients With Bronchial Anthracofibrosis

Incidence of Mycobacterium tuberculosis in Patients With Bronchial Anthracofibrosis

Systemic lupus erythematosus and tuberculosis

Infections, renal failure and cardiovascular disease account for the majority of mortality in systemic lupus erythematosus (SLE). Although most infections are caused by Gram-positive or Gram-negative bacteria, there is an increase in the incidence of Mycobacterium tuberculosis and other opportunistic infections that also account for increased mortality. The higher prevalence of tuberculous infections in SLE is attributed to multiple immune abnormalities seen in these patients. SLE and tuberculosis (TB) interact in complicated ways - they may have similar presentation and may mimic each other. In an individual patient, it becomes important to differentiate one from the other. In this review, we have highlighted the complex interactions of these diseases, the impact of one on the other and the various modalities available for the evaluation and management and their shortcomings. Considering the high prevalence of TB in India, it becomes all the more important for us to be aware of this interaction in our population.

Mycobacterium tuberculosis infection in immunocompromised hosts: A diagnostic challenge

The number of cases of tuberculosis (TB) in the United States declined by 45% between 1993 and 2006. This decline occurred disproportionately among United States–born persons (66%) compared to foreign-born individuals, among whom the number of cases actually increased by 5%. In solid-organ transplant recipients, the incidence of Mycobacterium tuberculosis (MTB) infection worldwide ranges between 0.35% and 15%, depending on the level of endemicity. This rate can be 36to 74-fold greater than that in the general population. The majority of MTB cases after transplantation represent reactivation of latent tuberculosis infection (LTBI), although acquisition of primary TB infection posttransplant and transmission of MTB via the transplanted organ are infrequent possibilities. Active TB in the posttransplantation setting can pose a number of challenges: atypical presentation leading to a delay in diagnosis, therapy associated with drug interactions and toxicities, graft rejection, and formidable morbidity and mortality. This is of particular concern in both patients with end-stage liver disease awaiting liver transplantation and liver transplant recipients, given the hepatotoxicity of several anti-TB medications and their associated drug interactions with immunosuppressants. In this issue of Liver Transplantation, Holty et al. present a systematic review and meta-analysis of TB in liver transplant recipients. They included cases of active MTB infection following liver transplantation as well as transplant candidates or recipients who received 6 months of therapy for LTBI prior to transplantation. The prevalence of active TB in liver transplant recipients was 1.3%. Extrapulmonary infection was seen in 67%, multiorgan involvement was seen in 27%, and 31% died. Tuberculin skin test (TST) results were as follows: a) Among 38 cases of posttransplant active TB with known pretransplant TST status, 37% were TST-positive, 53% were negative, and 11% were anergic; among 17 of these patients who had a posttransplant TST, only 35% were positive. b) In 3 studies with 2972 patients who underwent liver transplantation, 31% of the patients had a pretransplant TST, and 13% of these were positive. None of the TST-positive patients who received isoniazid therapy for at least 6 months developed active TB, whereas 7 TST-positive patients developed active disease without such therapy (mean follow-up, 54 months). Short-term mortality in patients with active posttransplant TB was 31%, with 65% of deaths directly attributed to MTB infection. Because reactivation of LTBI represents the majority of posttransplant cases of active TB, it is prudent to screen and identify such patients before transplantation for consideration of appropriate therapy for LTBI. Until recently, TST was the only test available for LTBI diagnosis. As noted previously, TST was notoriously insensitive: 64% of patients with posttransplant active TB were either TST-negative or anergic prior to transplantation, and 65% of patients had a negative posttransplant TST in the setting of active TB. TST has

Late Occurrence of Pleural and Peritoneal Effusion Due to Mycobacterium tuberculosis Infection (TB) in a Patient With Posttransplantation Recurrent HCV Chronic Hepatitis: Safety of Peginterferon and Ribavirin Treatment After Recovery of TB:— A Case Report

The late occurrence of a large and often long-lasting effusion in the pleural and peritoneal cavities after liver transplantation is an uncommon and poorly understood complication. Even rarer (<1%) is the incidence of Mycobacterium tuberculosis (MT) in Western world series. Herein we have described a case of massive pleural effusion and ascites due to MT occurring 22 months after liver transplantation for hepatitis C virus (HCV) cirrhosis. The infection was successfully treated with no hepatotoxicity or rejection, so that it was possible to start antiviral treatment with peginterferon and ribavirin for recurrent HCV without reactivation of MT infection.

Tuberculosis in end‐stage renal disease patients on hemodialysis

Recent studies have shown that there is an increase in the incidence of mycobacterium tuberculosis (MBT). This is more prevalent among immune compromised patients (those on dialysis) and recipients of organ transplants. Furthermore, extra-pulmonary presentation appears to be more common and difficult to diagnose. We aimed in this study to assess and evaluate the presentation of MBT in a retrospective study conducted among 256 hemodialysis (HD) patients where 18 of them were diagnosed and managed for tuberculosis over a 10-year period between 1990 and 2000. The mean age of the patients was 38 years (21-75 years). The mean interval between the onset of HD and the time of diagnosis was about 24 months (1-120 months). The diagnosis of tuberculosis was made either by isolation of acid-fast bacilli (AFB), the typical caseating granuloma on biopsy, or by recovery of tubercle bacilli from the culture of the biopsy material. Extra-pulmonary tuberculosis was more common (77.8%) than pulmonary tuberculosis (22.2%). The various extra-pulmonary tuberculosis sites noted were cervical lymphadenitis (16.7%), gastrointestinal (16.7%), genitourinary (11.1%), peritonitis (11.1%), pleural effusion (5.6%), pericardial effusion (5.6%), miliary tuberculosis (5.6%), and pyrexia of unknown origin (5.6%). None of the patients with extra-pulmonary tuberculosis had evidence of pulmonary tuberculosis. The atypical presentation with insidious onset was quite common. Anergy to tuberculin skin test was noticed in 56% of cases. All of our patients received modified antituberculosis treatment for 1 year with adequate response, and without undue side effects. We conclude that a high index of suspicion is required especially in the diagnosis of extra-pulmonary tuberculosis, and when there is a high percentage of anergy to tuberculin skin test. Tissue biopsy both for characteristic histology and demonstration of MTB, either by staining or culture, remains the main criteria for the diagnosis of extra-pulmonary tuberculosis.

Diagnosis and Treatment of Tuberculosis in Hemodialysis and Renal Transplant Patients

Background: The incidence of Mycobacterium tuberculosis in hemodialysis (HD) and renal transplant (RT) patients in developing countries is high. With the resurgence of tuberculosis in the US, insights gained in the diagnosis and treatment of this infection in HD and RT patients in developing countries should be valuable to physicians in the West. Methods: A retrospective study of 40 cases of tuberculosis, 24 in HD patients (24/177, 13.6%) and 16 in RT patients (16/109, 14.7%) diagnosed over a period of 21 months in one center. Results: The clinical features, diagnostic procedures, and management dilemmas of this group of patients are described in this report. Diabetes mellitus was the most common associated disease in both groups of patients. Fever, the most common presenting sign, was persistent low grade in 66.6% of HD patients and high intermittent in 56.2% of RT patients. Fever of unknown origin was only seen in RT patients. Pulmonary involvement was most common in both groups, presenting either as infiltrates or effusions. Tuberculous peritonitis was seen only in HD patients (33.3%). Eight HD patients were treated for tuberculosis for variable periods prior to transplantation, 4 of whom had less than 6 months of therapy. None had a recurrence of tuberculosis after transplantation. Because of the known cyclosporin-lowering effect of rifampicin resulting in an increased cost of immunosuppressive therapy, 13 patients were treated successfully with rifampicin-sparing therapy. Conclusion: Tuberculosis should be included in the differential diagnosis of fever in HD and RT patients, especially if fever is of unknown origin in the RT patient. M. tuberculosis in the renal transplant patient can present with high intermittent fever. Partial treatment of tuberculosis is sufficient prior to renal transplantation but treatment should be continued to completion after transplantation. If the cost of immunosuppressive therapy is prohibitive because of rifampicin, rifampicin-sparing antituberculosis therapy can be successfully employed in RT patients.

Multidrug-Resistant Tuberculous Iliopsoas Abscess

Psoas abscess is an important disease with subtle and often nonspecific presentation that frequently provides a diagnostic challenge. Of late it is only rarely caused by Mycobacterium tuberculosis (MTB). In a recent retrospective review of extrapulmonary tuberculosis among 196 patients with human immunodeficiency virus (HIV) infection and 153 HIV-negative patients only one with disseminated infection had psoas abscess at postmortem. However the recent resurgence of tuberculosis may result in changes in the etiologic trends of psoas abscess. This increase in the incidence of MTB has been reported worldwide however there has also been concurrent increase in the prevalence of MTB resistant to first-line antituberculosis agents especially among patients with HIV infections. Multidrug-resistant MTB (MDR-MTB) have been defined as strains resistant to isoniazid and rifampicin with or without resistance to other drugs. (excerpt)

Tuberculous bronchoesophageal fistulae in patients infected with the human immunodeficiency virus: A case report and review

B ronchoesophageal fistulae are classified as congenital or acquired; most of those seen in adults are acquired. The incidence of Mycobacterium tuberculosis (MTB) infection has increased dramatically in the United States as a result of the epidemic of human immunodeficiency virus (H/V) infection. 1 In patients who are not infected with H/V, esophageal tuberculosis (TB) has rarely been described as a manifestation of MTB infection. 2 An MTB infection in patients infected with HIV may present atypically and may have a more virulent course.l,3 Tuberculous bronchoesophageal fistula (TBEF) in patients infected with HIV was first reported by Allen et al. 4 in 1991, and only six addit ional patients have been described in the literature. 5-a We present a patient with TBEF who is unique because she was not born in and did not travel to a developing country.

Tuberculin testing in patients with human immunodeficiency virus/acquired immune deficiency syndrome.

After declining for decades, the incidence of Mycobacterium tuberculosis is increasing. The Mantoux tuberculin skin test, which uses purified protein derivative (PPD) of tuberculin, has been used for years as a screening device to detect the presence of exposure and infection to tuberculosis. However, the advent of human immunodeficiency virus (HIV) has elicited many questions regarding the validity of traditional standards for PPD administration and interpretation. The uncertainties in interpreting tuberculin skin tests in immunocompromised individuals is part of the challenge that is being faced by the health-care profession in this 2nd decade of acquired immune deficiency syndrome. This article will help advanced practice nurses understand the relationship between the immune system, tuberculosis, and the PPD skin test; the problem of anergy with immunocompromised patients, particularly those who are HIV-infected; issues involved in placement and interpretation of the results of the PPD test; new Agency for Health Care Policy and Research (AHCPR) standards for PPD interpretation with HIV-infected persons; the "booster" effect and two-step PPD testing; concerns regarding bacille Calmette-Guérin vaccine; and the use of a critical pathway to aid in rapid identification and isolation of the patient with HIV admitted with a potential diagnosis of tuberculosis versus Pneumocystis carinii pneumonia.

Tuberculosis in Saudi Arabia: Epidemiology and incidence of Mycobacterium tuberculosis and other mycobacteriai species

The epidemiology of mycobacterial infections was studied in a wide cross-section of the Jeddah population over 2 years (1987–1989). Saudis, non-Saudis and patients from a stable population attending National Guard King Khalid Hospital (NGKKH) were compared. The ratio of Saudi to non-Saudi was 1:2 and males accounted for 65% of the total. The incidence was highest among young adults although the peak varied slightly between Saudi and non-Saudi patients. Extra-pulmonary tuberculosis was also preponderant among young adults, particularly females. Variants of Mycobacterium tuberculosis were investigated for the first time in Saudi Arabia. African and Asian variants were isolated from both Saudi and non-Saudi patients, the former being more numerous. Extra-pulmonary tuberculosis, particularly lymphadenopathy, accounted for a large proportion of mycobacterial infections, 59% at NGKKH. Mycobacterial species other than M. tuberculosis were fully identified and accounted for 9% of the isolates, Mycobacterium fortuitum and Mycobacterium chelonei being the two most prevalent.