Non tuberculosis mycobacteria isolates among new and previously treated pulmonary tuberculosis patients in Nigeria

ObjectiveTo determine the prevalence of non tuberculosis mycobacteria (NTM) among new and previously treated tuberculosis (TB) patients in Nigeria.MethodsIt was a retrospective study. A total of 102 sputum smear positive samples/culture isolates from pulmonary TB patients (41 new smear positive and 61 smear positive retreatment cases) were sent to the Institute of Tropical Medicine, Antwerp Belgium between 2007-2009. Data on patients' characteristics were retrieved from their treatment cards.ResultsAmong the 102 samples, 25 isolates results (20 were culture negative while 5 were contaminated) were excluded from the study. Data were available for 77 mycobacterium isolates. 70 (90.9%) were identified as Mycobacterium tuberculosis and 7 (9.1%) as atypical mycobacteria. Among the atypical mycobacteria, three of them were Mycobacterium fortuitum, two Mycobacterium intracellulare and two Mycobacterium chelonae. Of the seven isolates with atypical mycobacteria, 4 (57.1%) were from previously treated patients, while 3 (42.9%) were new sputum positive patients. There was no statistically significant difference in NTM infection between new and previously treated pulmonary TB patients (P =0.97).ConclusionsThe study shows the involvement of atypical mycobacterium in pulmonary infection in both new and previously treated TB patients. Therefore, there is a need to carry out culture and drug susceptibility testing in all pulmonary TB patients especially those who had failed conventional DOTS treatment to rule out NTM infections.     

Non-tuberculous mycobacterial osteomyelitis: an unusual cause of hip pain in immunocompetent children

Non-tuberculous mycobacteria (NTM) are an unusual cause of osteomyelitis in immunocompetent children. Diagnosis is often difficult due to the paucity of clinical symptoms and a subtle course of the disease. NTM comprise a group of about 91 identified species of environmental mycobacteria that cause infections most frequently in immunocompromised individuals or in patients with predisposing factors. Cervical lymphadenitis is the most common presentation of NTM infection in children. Invasive and recurrent infections with these organisms have been associated with a genetic defect of the interferon γ-receptor. We report a 3-year-old immunocompetent girl who presented a NTM osteomyelitis of the left femur. Four months before she had been treated with medical and surgical therapy for a mycobacterium avium complex cervical lymphadenitis. Polymerase chain reaction assay on bone aspirate specimens confirmed the diagnosis of mycobacterium avium osteomyelitis. The patient was treated successfully with clarithromycin and rifampicin for 6 months.     

Clinical Aspects of Pulmonary Nontuberculous Mycobacteriosis

Nontuberculous mycobacterial (NTM) infections are an emerging problem. Common organisms include Mycobacterium avium, M. intracellulare, and M. kansasii, along with the M. avium intracellulare complex (MAC), which includes both M. avium and M. intracellulare. Typically, NTM infections affect the lungs and subsequently demonstrate a chronic course. Therefore, persistent respiratory symptoms generally indicate of the presence of pulmonary NTM diseases, and chest radiography, along with a sputum examination, are essential for its diagnosis. Because NTM are ubiquitous environmental organisms, a positive culture from a minimum of two separate expectorated sputum samples are required to make a diagnosis. The repertoire of effective drugs for treatment is considerably limited, indicating the need for long-term management with multiple drugs. Establishing a treatment regimen with high therapeutic efficacy and safety is an important issue for the future.     

Nontuberculous Mycobacterial Infections: A Clinical Review

Abstract. Nontuberculous mycobacteria (NTM) are important environmental pathogens that can cause a broad spectrum of diseases. The last few years brought several changes in this expanding field: The number of infections that can be associated with specific species as well as the number of new species as etiological agents has exploded due to the development of new diagnostic tools. The incidence of disseminated Mycobacterium avium complex (MAC) infections in HIV patients is decreasing with more potent anti-HIV treatments, while the rate of pulmonary NTM infection and disease as well as the prevalence of Buruli ulcer, a chronic, necrotizing, progressive ulcerous disease caused by Mycobacterium ulcerans, is increasing. The disease manifestations depend on the interaction between the specific mycobacterial pathogen and the hosts immune system. This article presents an update of the epidemiology, diagnosis, and treatment of NTM-associated pulmonary disease, lymphadenitis, skin and soft tissue disease, skeletal infection and foreign body- and catheter-related NTM infections.     

Diagnosis and treatment of atypical mycobacterial infections of the respiratory tract

INTRODUCTION: Non tuberculous mycobacteria (NTM), unlike tuberculous mycobacteria, are not strictly human pathogens. The diagnosis of infection and the choice of treatment remain difficult. BACKGROUND: Evidence of a NTM in a pulmonary sample is not synonymous with infection. The diagnosis depends on the association of clinical, radiological and microbiological factors. If a NTM is isolated from a respiratory sample, the probability of infection depends on the species. The main NTMs responsible for pulmonary infection in France are Mycobacterium avium intracellulare, Mycobacterium xenopi, Mycobacterium kansasi and Mycobacterium abscessus. Their management is difficult and poorly understood. Treatment is well established for M. avium intracellulare and M. kansasii, with combinations of clarithromycin-rifampicin-ethambutol and isoniazid-rifampicin-ethambutol respectively. For M. xenopi, the optimal treatment is not known and a combination of clarithromycin-rifampicin-ethambutol, with moxifloxacin as an alternative, is currently recommended. In general, treatment is prolonged and often associated with problems of tolerance. VIEWPOINT AND CONCLUSION: The management of NTM infection, taking into account of the increase in patients "at risk", is an important issue. Further studies are needed to improve the criteria for infection and to find the optimal therapeutic combinations.     

The relative frequency of Mycobacterium tuberculosis and Mycobacterium avium infections in HIV positive patients, Ahvaz, Iran

ObjectiveTo estimate the prevalence of Mycobacterium tuberculosis (M. tuberculosis) and Mycobacterium avium (M. avium) infections in HIV-positive patients suspected to have pulmonary and extrapulmonary mycobacterial co-infection using PCR technique.MethodsTotally 50 samples comprising sputum, pleural fluid and CSF taken from HIV positive patients suspected to have mycobacterial infection, were processed. The demographic information and results of acid fast staining and culture were recorded for each patient. The PCR for detecting of M. tuberculosis comprised of specific primers targeting IS6110 gene sequence. For detecting of M. avium, PCR with primers that amplifies the mig gene were used.ResultsFrom 50 samples processed, 45 were sputum (90%), 3 pleural fluid (6%) and 2 CSF (4%). In total, 8 (16%) were culture positive, 7 had positive acid fast staining (14 %) and 13 samples (26%) were positive using PCR technique. All the positive samples were sputum and belonged to patients with pulmonary infection. Of these, 9 were positive for M. tuberculosis (69.2%) and 4 were identified as M. avium (30.8%), which 2 out of 13 positive samples showed mixed infections by both mycobacteria.ConclusionsThe PCR shows the highest detection rate (26%) of mycobacteria compared with culture and acid fast staining. The majority of infections were with M. tuberculosis (18%) and this shows the importance of this mycobacterial co-infection in HIV positive patients in the region of study.     

杭州地区流行非结核分枝杆菌鉴定、易感因素和耐药性分析

目的了解近年杭州地区非结核分枝杆菌(NTM)感染、优势菌种及其耐药性。方法采用PNB/TCH生长试验对1 972例患者分枝杆菌阳性培养物标本中NTM进行初步鉴定。采用分枝杆菌分子线性探针法和16SrRNA基因PCR产物测序鉴定NTM菌种。分析性别和年龄对NTM易感性的影响。采用浓度比例法检测NTM分离菌株对异烟肼(INH)、利福平(RFP)、链霉素(SM)、乙胺丁醇(EMB)、氧氟沙星(OFX)、卡那霉素(KM)的敏感性。结果 9.8%(193/1 972)分枝杆菌阳性培养物标本PNB/TCH生长试验结果阳性。分子线性探针法和16SrRNA基因PCR产物测序结果显示,193例PNB/TCH生长试验阳性标本中,66.3%为单一NTM、18.1%为2种分枝杆菌、8.3%为结核分枝杆菌、7.3%为非分枝杆菌属细菌感染。173株NTM(单一感染128株+混合感染45株)中,胞内分枝杆菌占57.8%,其次为脓肿分枝杆菌、堪萨斯分枝杆菌、龟分枝杆菌和鸟分枝杆菌(12.1%、9.8%、9.8%和5.8%)。35例分枝杆菌混合感染标本中,28.5%和20.0%分别为胞内分枝杆菌或龟分枝杆菌与结核分枝杆菌混合感染。NTM感染者男性多于女性(1.67∶1),50岁以上人群感染率(80.4%)高于50岁以下人群(P0.01),肺部感染比例(95.1%)远高于其他部位(P0.01)。NTM分离株对INH耐药率为100%,对其他5种抗结核药物的耐药率也高达70.3%~90.6%。结论胞内分枝杆菌是杭州地区近年优势流行的NTM菌种,NTM主要引起肺部感染且中老年人易感,NTM临床菌株对常用抗结核药物有很高的耐药性。     

Infecciones cutáneas y de partes blandas por micobacterias no tuberculosas

The frequency of isolation as well as the number of species of non-tuberculous mycobacteria (NTM) has increased in the last years. Nearly every pathogenic species of NTM may cause skin and soft tissue infections, but rapidly growing mycobacteria (Mycobacterium fortuitum, Mycobacterium chelonae and Mycobacterium abscessus), Mycobacterium marinum and Mycobacterium ulcerans are the most commonly involved. Many of these cutaneous mycobacteriosis, such as rapidly growing mycobacteria, M. marinum, Mycobacterium avium complex, Mycobacterium kansasii or Mycobacterium xenopi are world-wide distributed. In contrast, some others have a specific geographical distribution. This is the case of M. ulcerans, which causes a cutaneous diseases endemic of Central and West Africa (Buruli ulcer) and Australia (Bairnsdale ulcer), being the third mycobacterial infection after tuberculosis and leprosy. Cutaneous mycobacteriosis usually appear either after contact of traumatic or surgical wounds with water or other contaminated products, or, secondarily, as a consequence of a disseminated mycobacterial disease, especially among immunosuppressed patients. For an early diagnosis, it is necessary to maintain a high degree of suspicion in patients with chronic cutaneous diseases and a history of trauma, risk exposure and negative results of conventional microbiological studies. In general, individualized susceptibility testing is not recommended for most NTM infections, except for some species, and in case of therapeutic failure. Treatment includes a combination of different antimicrobial agents, but it must be taken into account that NTM are resistant to conventional antituberculous drugs. Severe cases or those with deep tissues involvement could also be tributary of surgical resection.     

Mycobacterium kansasii Infection in a Patient Receiving Biologic Therapy—Not All Reactive Interferon Gamma Release Assays Are Tuberculosis

Mycobacterium kansasii, a nontuberculous mycobacterium, can lead to lung disease similar to tuberculosis. Immunotherapeutic biologic agents predispose to infections with mycobacteria, including M kansasii. T-cell–mediated interferon gamma release assays like QuantiFERON-TB Gold Test (QFT) are widely used by clinicians for the diagnosis of infections with Mycobacterium tuberculosis; however, QFT may also show positive result with certain nontuberculous mycobacterial infections. We report a case of M kansasii pulmonary infection, with a positive QFT, in an immunocompromised patient receiving prednisone, leflunomide and tocilizumab, a humanized anti–interleukin-6 receptor monoclonal antibody. This case highlights the risk of mycobacterial infections with the use of various biologic agents and the need for caution when interpreting the results of interferon gamma release assays.     

A case report of Mycobacterium chelonae keratitis and a review of mycobacterial infections of the eye and orbit

Mycobacteria are unusual causes of keratitis and other ocular infections but the outcome of infection is often serious. We report a case of keratitis due to Mycobacterium chelonae, a rapidly growing environmental mycobacterium, in a soft contact-lens wearer, and discuss the difficulty and delay in identifying the organism, twice erroneously identified as Nocardia asteroides on morphological grounds. Despite in vitro susceptibility, the response to anti-bacterial agents was negligible and a second keratoplasty was required after a recurrence of disease at the donor-host junction. We review the role of mycobacteria as the cause of keratitis and other forms of ocular disease.     

15例非结核分枝杆菌肺病临床分析

目的探讨非结核分枝杆菌（NTM）肺病的临床特征。方法对武汉市结核病防治所确诊为NTM肺病的15例患者的临床资料进行分析。结果15例NTM肺病中,快速生长型9例,其中脓肿分枝杆菌6例,龟分枝杆菌1例,耻垢分枝杆菌和偶然分枝杆菌感染各1例;慢速生长型6例,其中鸟分枝杆菌3例,胞内分枝杆菌2例,海分枝杆菌1例。主要症状依次为咳嗽、咳白粘痰、咯血和发热;NTM对大部分抗结核药物呈现高度的原始耐受性,对喹诺酮类、大环内脂类和氨基糖甙类的耐药率相对较低。结论NTM肺病常发生于有慢性肺部基础疾病及免疫功能相对低下的患者,其临床特征与肺结核相似,常规抗结核治疗疗效差。     

Mycobacterium neoaurum bacteremia in a hemodialysis patient

Bacteremia due to Mycobacterium neoaurum, a rapidly growing mycobacterium, is described in a diabetic woman on hemodialysis. This is the first reported case of M neoaurum bacteremia in Canada. The organism initially grew on standard BacT/Alert SA aerobic blood cultures, and was subsequently positively identified using 16S rRNA sequence analysis. The present case serves to reinforce the need for a high index of clinical suspicion of infections caused by unusual microorganisms in the context of an immunocompromised hostKey Words: 16S rRNA sequencing, Hemodialysis infection, Mycobacterium neoaurum The present report describes a case of Mycobacterium neoaurum bacteremia and arteriovenous shunt infection in a hemodialysis patient. M neoaurum, a member of the Mycobacterium parafortuitum complex, belongs to the group of rapidly growing environmental mycobacteria that are responsible for a broad spectrum of illnesses, including surgical wound and catheter infections, and disseminated cutaneous and pulmonary diseases (1). To our knowledge, this is the first case of infection due to M neoaurum reported in the Canadian literature.     

Clinical features of infection caused by non-tuberculous mycobacteria: 7 years’ experience

Introduction

Non-tuberculous mycobacteria (NTM) are ubiquitous organisms associated with various infections. The aim of the study was to determine the most relevant clinical characteristics of NTM during the 7-year period.

Methodology

A retrospective study of NTM infections was conducted between January 2009 and December 2016. The American Thoracic Society/Infectious Disease Society of America criteria were used to define cases of pulmonary or an extrapulmonary site.

Results

A total of 85 patients were included in the study. Pulmonary cases predominated 83/85 (98%), while extrapulmonary NTM were present in 2/95 (2%) patients. Overall, ten different NTM species were isolated. The most common organisms were slow-growing mycobacteria (SGM) presented in 70/85 (82.35%) patients. Isolated SGM strains were Mycobacterium avium complex (MAC) in 25/85 (29.41%) patients, M. xenopi in 20/85 (23.53%) patients, M. kansasii in 15/85 (17.65%) patients and M. peregrinum and M. gordonae in 5/85 (5.88%) patients each. Isolated rapid-growing mycobacteria (RGM) strains were M. abscessus in 8/85 (9.41%) patients, M. fortuitum in 4/85 (4.71%) patients and M. chelonae in 3/85 (3.53%) patients. Almost all patients (98%; 83/85) had comorbidities. Among 75 (88.24%) patients who completed follow-up, 59 (69.41%), 10 (11.76%) and 6 (7%), were cured, experienced relapse and died, respectively.

Conclusion

In the present study, pulmonary NTM infections were more frequent compared to extrapulmonary disease forms. SGM were most common isolates with MAC pulmonary disease the most frequently found. Comorbidities have an important role in NTM occurrence. Further investigation should focus on an NTM drug susceptibility testing.

     

Misdiagnosis of tuberculosis and the clinical relevance of non—tuberculous mycobacteria in Zambia

ObjectiveTo determine the accuracy of TB diagnosis of TB in Zambia in the era of increasing HIV prevalence.MethodsSputum of the clinically diagnosed TB cases was additionally subjected to liquid culture and molecular identification. This study distinguished between TB cases confirmed by positive Mycobacterium tuberculosis (M. tuberculosis) cultures and mycobacterial disease caused by non-tuberculous mycobacteria (NTM).ResultsOnly 49% of the 173 presumptively diagnosed TB cases was M. tuberculosis cultured, while in 13% (22) cases, a combination of M. tuberculosis and NTM was found. In 18% of the patients only NTM were cultured. In 28%, no mycobacteria was cultivable. HIV positive status was correlated with the isolation of NTM (P <0.05).ConclusionsThe diagnosis of tuberculosis based on symptoms, sputum smear and/or chest X-ray leads to significant numbers of false-positive TB cases in Zambia, most likely due to the increased prevalence of HIV. The role of NTM in tuberculosis-like disease also seems relevant to the false diagnosis of TB in Zambia.     

The expanding spectrum of Mycobacterium avium complex-associated pulmonary disease

Nontuberculous mycobacteria (NTM) are increasingly recognized as important pulmonary pathogens. Mycobacterium avium intracellulare complex (MAC) causes most lung infections due to NTM. Patients with preexisting lung disease or immunodeficiency are at greatest risk for developing MAC infection. The majority of MAC pulmonary cases, however, occur in immunocompetent elderly women in association with nodular infiltrates and bronchiectasis. More recently, pulmonary disease has also been described in immunocompetent patients after exposure to MAC-contaminated hot tubs. We describe a case of aggressive MAC lung disease in a young immunocompetent female patient without preexisting lung disease whose clinical and pathologic characteristics do not fit into any of these categories and may represent a unique manifestation of MAC lung disease.     

四川省非结核分枝杆菌耐药分析

目的 探讨非结核分枝杆菌(non - tuberculosis mycobacterium,NTM)的流行病学特征和耐药现状,为NTM肺病的防治策略提供科学依据.方法 对2002 - 2011年四川省结核病参比实验室收集的分枝杆菌进行药物敏感性检测及菌种鉴定.对确诊为NTM病例进行流行病学分析.结果 2002 - 2011年四川省结核病参比实验室对2356个分枝杆菌菌株进行菌种鉴定,确诊为NTM的为251株,占10.65％,其中245株对异烟肼、对氨基水杨酸钠、乙胺丁醇、利福平、链霉素等常用抗结核药物存在不同程度的耐药,耐药率高达97.60％,且大多菌株同时对多种抗结核药物耐药.结论 四川省NTM对抗结核药物的耐药率高,研究、探索抗NTM的新药及更为有效的诊断方法是当务之急.     

T-SPOT.TB Test(R) results in adults with Mycobacterium avium complex pulmonary disease

The tuberculin skin test is limited by its inability to distinguish between infection with Mycobacterium tuberculosis and non-tuberculous mycobacteria (NTM). Newer interferon-gamma release assays using ESAT-6 and CFP-10 antigens should have a higher specificity for tuberculosis but have not been widely tested in adults with pulmonary disease due to NTM. In this study, we tested the T-SPOT.TB Test in patients with pulmonary disease due to Mycobacterium avium complex (MAC), the most common disease-causing NTM. Fourteen patients with prior culture-confirmed pulmonary disease due to MAC, 10 patients with prior culture-confirmed tuberculosis and 4 healthy controls were interviewed and tested with the T-SPOT.TB Test. 13 patients with MAC disease and 4 healthy subjects (negative controls) had non-reactive T-SPOT.TB results and 10 patients with prior tuberculosis (positive controls) had reactive results. One patient with MAC disease had a minimally reactive result on initial testing and a non-reactive result on re-testing. The T-SPOT.TB Test had a specificity of 94% for distinguishing between patients with prior MAC disease and prior tuberculosis disease, and will be useful in low tuberculosis prevalence settings where most mycobacterial infections are due to MAC. Reactions to the T-SPOT.TB Test may persist months to years after treatment of tuberculosis.     

Mycobacterium tuberculosis in a HIV-1-infected population from Southeastern Brazil in the HAART era

Objective To evaluate retrospectively the microbiological profile of Mycobacterium species isolated from HIV‐infected patients attending the HIV/TB reference health care units in São José do Rio Preto, Brazil. Method Retrospective evaluation of all HIV‐1 positive patients whose IAL‐SJRP laboratorial analysis was positive for Mycobacterium sp. after diagnosis of HIV Infection, from January 2000 to December 2006. Results Of 198 patients, acid‐fast staining detected mycobacteria early in 41%. Culture revealed 52.5% to be infected with Mycobacterium tuberculosis (MT). 42.4% had non‐tuberculous mycobacteria (NTM) and 5.1% had MT/NTM positive cultures. Eleven per cent of MT strains were resistant to at least one of the antimycobacterial drugs and 3.1% were multidrug resistant. 39.4% of isolated mycobacteria were NTM species. Conclusion Our data may serve as a starting point for further comparisons with other Brazilian regions and other developing countries. The data may provide important clues to the future understanding, prevention and control of such co‐infections around the world.     

Isolation prevalence of pulmonary nontuberculous mycobacteria in Ontario in 2007

BACKGROUND:

The reported prevalence of pulmonary nontuberculous mycobacteria (NTM) infections is increasing.

OBJECTIVE:

To determine the ‘isolation prevalence’ of NTM in 2007 and compare it with previously published research that examined the increasing rates of isolation of NTM from clinical pulmonary specimens between 1997 and 2003.

METHODS:

Isolation prevalence was investigated retrospectively by reviewing a cohort of all positive pulmonary NTM culture results from the Tuberculosis and Mycobacteriology Laboratory, Public Health Laboratory (Toronto, Ontario) in 2007, which identifies at least 95% of NTM isolates in Ontario. Isolation prevalence was calculated as the number of persons with a pulmonary isolate in a calendar year divided by the contemporary population and expressed per 100,000 population. Changes in isolation prevalence from previous years were assessed for statistical significance using generalized linear models with a negative binomial distribution.

RESULTS:

In 2007, 4160 pulmonary isolates of NTM were collected from 2463 patients. The isolation prevalence of all species (excluding Mycobacterium gordonae) was 19 per 100,000 population in 2007 – an increase from previous observations reported for Ontario – corresponding to an average annual increase of 8.5% from 1997 to 2007 (P<0.0001). Average annual increases in isolation prevalence of Mycobacterium avium complex (8.8%, P<0.0001) and Mycobacterium xenopi (7.3%, P=0.0005) were largely responsible for the overall increase, while prevalence rates of rapidly growing mycobacteria remained relatively stable.

CONCLUSION:

The isolation prevalence of pulmonary NTM continues to increase significantly in Ontario, supporting the belief that pulmonary NTM disease is increasingly common.     

Prevalence of gastroesophageal reflux disease in patients with nontuberculous mycobacterial lung disease

BACKGROUND: Knowledge of the relationship between respiratory disorders and gastroesophageal reflux disease (GERD) is increasing. However, the association between GERD and pulmonary disease caused by nontuberculous mycobacteria (NTM) has not been studied in detail. We investigated the prevalence of GERD in patients with the nodular bronchiectatic form of NTM lung disease. METHODS: Fifty-eight patients with the nodular bronchiectatic form of NTM lung disease underwent ambulatory 24-h esophageal pH monitoring. Of the 58 patients, 27 patients were identified as having Mycobacterium avium complex infection (15 with Mycobacterium intracellulare and 12 with M avium), and 31 patients had Mycobacterium abscessus pulmonary infection. RESULTS: The prevalence of GERD in patients with the nodular bronchiectatic form of NTM lung disease was 26% (15 of 58 patients). Only 27% (4 of 15 patients) had typical GERD symptoms. No statistically significant differences were found between patients with GERD and those without GERD with regard to age, sex, body mass index, or pulmonary function test results. However, patients with GERD were more likely to have a sputum smear that was positive for acid-fast bacilli (12 of 15 patients, 80%), compared with patients without GERD (19 of 43 patients, 44%) [p = 0.033]. In addition, bronchiectasis and bronchiolitis were observed in more lobes in patients with GERD than in patients without GERD (p = 0.008 and p = 0.005, respectively). CONCLUSIONS: Patients with the nodular bronchiectatic form of NTM lung disease have a high prevalence of increased esophageal acid exposure, usually without typical GERD symptoms.