Presence Of Nontuberculous Mycobacteria Research Articles

NONTUBERCULOUS MYCOBACTERIA DIVERSITY IN KARST WATERS AND BIOFILMS IN BULGARIAN CAVES

Background: Nontuberculous Mycobacteria (NTM) are emerging pathogens causing opportunistic infections in humans and animals. Their distribution in the waters and caves of Bulgaria is poorly studied. Climatic changes are associated with changes in the amplitudes of ambient and water temperature, as well as changes in the amount of precipitation which play an essential role in the creation of reservoirs of some types of NTM in the environment. Material and Methods: We optimized the methods for successful isolation of environmental NTM and then used molecular genetic methods for identification. Results: A total of 235 samples (karst water, sediments, soil, bat guano) were collected in some caves of the following karst regions: 203 in Vratsa Karst area, 204 in Ponor Karst area, 205 in Bezdenski area and 303 in Karst and caves of Bosnek region. Primary isolation of mycobacteria by Löwenstein–Jensen at room temperature was more successful than on liquid media at 37°C. We identified NTM in 10% (n=24) from these materials. Diverse NTM included: M. chelonae (n=3), M. gordonae (n=2), M. intermedium (n=3), M. scrofulaceum (n=1), M. szulgai (n=4), M. fortuitum group (n=4), NTM mix culture (n=5), M. terrae complex (n=1), Mycobacterium sp. (n=1). Rapidly growing NTM (M. chelonae, M. fortuitum group) were the most common. The isolates belonged to group of environmental saprophytes (Risk group 1) and potential pathogens (Risk group 2). Conclusions: We successfully implemented a procedure for decontamination and isolation of NTM from the environment. For the first time in the country, NTM species were identified in biofilms, karst waters, soil and bat guano within caves. The presence of NTM in cave ecosystems represents a potential source for human infection.

ОСОБЕННОСТИ ТЕЧЕНИЯ МИКОБАКТЕРИОЗА ЛЕГКИХ В ЗАВИСИМОСТИ ОТ ВЫЯВЛЕНИЯ ВОЗБУДИТЕЛЯ В МОКРОТЕ

Objective: to evaluate treatment effectiveness in patients with mycobacterial pulmonary disease and its association with mycobacteria detection in sputum. Materials and methods. The study enrolled 196 patients with confirmed mycobacterial pulmonary disease. The diagnosis was established as per ATS/IDSA criteria (2007). The patients were divided into two groups: group 1 consisted of 108 patients with nontuberculous mycobacteria (NTM) detected in sputum; group 2 consisted of 60 patients with NTM detected in BAL and/or lung tissue samples. Female patients prevailed (78.6%). The average patients’ age was 56.9 ± 11.3 years. The time period from diagnosing pulmonary mycobacterial disease to commencementof combination antibacterial therapy varied from one month to 3.5 years. Patients were followed up during one year after treatment completion. Results. The most commonly identified NTM were MAC (M. аvium, M. intracellulare) and M. kansasii. The combination antibacterial therapy was administered to 168 (85.7%) patients. Clinical cure was more frequently achieved in the patients of group 2 compared to group 1 (21.7 and 3.7% respectively, р < 0.01). The frequency of clinical improvement without conversion of biological samples did not significantly differ between the groups (40 and 54.6% respectively, …). The frequency of relapse was similar in both groups and did not exceed 5%. Conclusion. The presence of NTM in BAL while the absence of NTM in sputum allows predicting more favourable disease course and better response to treatment.

The Effect of Cell-Free Nontuberculous Mycobacterium Supernatants on Antibiotic Resistance and Biofilm Formation of Opportunistic Pathogens

The presence of nontuberculous mycobacteria in biofilms on the surface of medical devices may affect the opportunistic pathogens that are common inhabitants of such biofilms. This study assessed the effect of Mycolicibacterium iranicum cell-free supernatants on biofilm formation and antibiotic susceptibility of Escherichia coli and Staphylococcus epidermidis differing in the anti-hemoglobin activity level. The cell-free supernatants have been shown to stimulate biofilm formation and also help reduce susceptibility of opportunistic pathogens to a number of antibiotics.

Non-Tuberculous Mycobacteria hsp65 in Relation to Bovine Subclinical Mastitis and IL6 Concentration in Cow's Milk.

Mastitis is a condition in which the mammary tissue becomes inflamed. Changes in color and the appearance of clots, as well as increases in cell counts in the milk, are all indicators of inflammation. Mastitis is a common occurrence in cows as a result of inframammary infections. The present study aimed to find out how often nontuberculous mycobacteria(NTM) mastitis occurs and how hp65 affects Interleukin (IL) 6 concentrations. The findings of the Modified Whiteside Test (MWT) on the milk samples from 70 cows, 50 sheep, and 30 goats revealed that 82.9%, 76.7%, and 46.7% of milk samples from cows, sheep, and goats were positive, respectively. This test demonstrated a range of positive milk sample MWT reactions, and the difference among the current positivity score results was statistically significant (P<0.05). The presence of NTM in analyzed milk samples from cows and sheep was confirmed by hsp65-based polymerase chain reaction (PCR) and gene sequencing, with significant differences (P<0.05) in 71.4% and 20% of milk samples from cows and sheep, respectively. The PCR detection of the NTM hsp65 gene in fecal samples from cows, sheep, and goats indicated that cows (80%) had the highest proportion of NTM hsp65 gene amplification, followed by goats (70%), while sheep fecal samples had the lowest amount (22%). The difference among the positive NTM hsp65-based PCR was statistically significant (P<0.05). The phylogenetic tree and sequence analysis of the hsp65 gene revealed two novel variant NTM hsp65 genes that were deposited in Gene Bank (GenBank acc. LC636294 and LC636295). The current examined NTM Hsp65 Mycobacterium sequences which were included in the Mycobacterium avium clade in the currently produced tree ELISA detection of IL6 concentration in cow's milk revealed that IL-6 concentration in mastitis milk was varied. The mean of IL-6 concentration in cow's mastitis milk with MWT scores (+++ve) and mean of IL6 concentration in each MWT scores (++ve), MWT scores (+ve), and -ve MWT cow's milk had a highly significant difference (P<0.001).

Transition between Mycobacterium tuberculosis and nontuberculous mycobacteria in recurrent "tuberculosis" patients.

Recurrence of tuberculosis (TB) is still a key issue in the control of tuberculosis. The presence of nontuberculous mycobacteria (NTM) complicates the diagnosis of recurrent TB due to similarity in clinical presentation. Herein, we have used molecular genotyping methods to identify mycobacteria species, and analyzed the characteristics of patients with transition between MTB and NTM. Eighty-nine patients with recurrent tuberculosis over the past 12years were included in our analysis. We found that 9 patients had NTM infections during the study period. Six patients were infected with different mycobacterial strains, half of which were transformed from NTM to MTB, and the other half from MTB to NTM. In addition, the other 3 patients were infected with the same NTM species. Further WGS analysis showed that only one patient had a relapse and the remaining two were classified as reinfection. In conclusion, our results demonstrate that a proportion of previously diagnosed recurrent TB cases are attributed to the transition between MTB and NTM, highlighting the significance of species identification prior to initiation of treatment. The recurrence of mycobacterial diseases is majorly noted within 1year after treatment completion.

Culture-Independent PCR Detection and Differentiation of Mycobacteria spp. in Antemortem Respiratory Samples from African Elephants (Loxodonta Africana) and Rhinoceros (Ceratotherium Simum, Diceros Bicornis) in South Africa.

Since certain Mycobacterium tuberculosis complex (MTBC) members, such as M. bovis, are endemic in specific South African wildlife reserves and zoos, cases of clinically important nontuberculous mycobacteria (NTM) in wildlife may be neglected. Additionally, due to the inability of tests to differentiate between the host responses to MTBC and NTM, the diagnosis of MTBC may be confounded by the presence of NTMs. This may hinder control efforts. These constraints highlight the need for enhanced rapid detection and differentiation methods for MTBC and NTM, especially in high MTBC burden areas. We evaluated the use of the GeneXpert MTB/RIF Ultra, the Hain CMdirect V1.0 line probe assay, and novel amplicon sequencing PCRs targeting the mycobacterial rpoB and ku gene targets, directly on antemortem African elephant (n = 26) bronchoalveolar lavage fluid (BALF) (n = 22) and trunk washes (n = 21) and rhinoceros (n = 23) BALF (n = 23), with known MTBC culture-positive and NTM culture-positive results. Our findings suggest that the Ultra is the most sensitive diagnostic test for MTBC DNA detection directly in raw antemortem respiratory specimens and that the rpoB PCR is ideal for Mycobacterium genus DNA detection and species identification through amplicon sequencing.

Utility of smear microscopy and GeneXpert for the detection of Mycobacterium tuberculosis in clinical samples

Rapid identification of Mycobacterium tuberculosis (MTB), its resistance to rifampicin and differentiation of MTB from nontuberculous mycobacteria (NTM) is necessary in the management of mycobacterial diseases. Culture, the "gold standard" for the detection of MTB, is time consuming. In spite of its rapidity and low cost, smear microscopy has poor sensitivity for the detection of acid-fast bacilli (AFB). A real-time PCR based rapid diagnostic method like GeneXpert MTB/RIF assay can simultaneously detect M. tuberculosis and rifampicin (RIF) resistance. Hence, we aim to compare the performance of GeneXpert MTB/RIF assay with smear microscopy and culture. In this descriptive cross-sectional study, we compared the performance of GeneXpert in pulmonary (N=127) and extrapulmonary (N=48) clinical specimens with other diagnostic methods like culture, Auramine O (AO), and Ziehl Neelsen (ZN) staining. Rifampicin resistance was detected only by GeneXpert. Demographic data and clinical history of the subjects were collected from the patient's hospital records. AO and ZN staining when compared with mycobacterial growth indicator (MGIT) culture showed the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 68.6, 95.7, 80, 92.4, 90.3% and 65.7, 95.7, 79.3, 91.8, 89.7%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of GeneXpert was 88.6, 93.6, 77.5, 97.0 and 92.6%, respectively. GeneXpert is the best available rapid diagnostic method as it can detect MTB and rifampicin resistance gene simultaneously. Accuracy and negative predictive value of GeneXpert was found to be better than AFB staining. Thus, a negative GeneXpert test can rule out TB. Further, a negative GeneXpert and a positive smear microscopy results indicate the presence of NTM. However, GeneXpert is expensive and needs sophisticated instrument when compared to smear microscopy.

Micobacterias no tuberculosas de sitios arqueológicos de México

Se examinaron varios edificios de nueve sitios arqueológicos en México para detectar la presencia de micobacterias y se pudieron aislar 45 cepas no tuberculosas. Se obtuvieron a partir de biopelículas usando medios selectivos con antibióticos y colorantes. Las cepas aisladas se determinaron como micobacterias mediante una PCR específica, posteriormente se identificaron con tres marcadores moleculares: genes rrs (16S rRNA), hsp65 y rpoB. Además se relacionaron los datos fisiográficos de las zonas arqueológicas estudiadas con el número de bacterias ácido alcohol resistentes mediante un análisis univariado de varianza. De las 45 cepas de micobacterias aisladas 21 correspondieron a Mycobacteroides chelonae; siete, M. abscessus; cinco, Mycolicibacterium flavescens; cuatro, Mycobacterium alvei; dos, M. fortuitum; y seis quedaron como Mycobacterium sp. La mayoría de las micobacteriasno tuberculosas(MNT) fueron aisladas de dos de las zonas arqueológicas: 25 de Guachimontones (Jalisco) y 13 de Atetelco (Estado de México). El análisis estadístico mostró que los factores ambientales como clima y la interacción temperatura-humedad-precipitación tuvieron una gran influencia en la presencia de este grupo bacteriano en las zonas arqueológicas.

Combination Therapy of Angiotherapy, Radiation Therapy, and Radiofrequency Ablation for Pulmonary Metastasis of Hepatocellular Carcinoma Accompanied by Nontuberculous Mycobacteria

With the advances in hepatocellular carcinoma (HCC) treatment, the lung metastasis of HCC is becoming increasingly important. In treating the lung metastasis of HCC, a multidisciplinary approach can lead to better results than systemic chemotherapy alone. Here, we report on a patient who presented with pulmonary masses, while the HCC was being controlled in the abdominal cavity. The presence of nontuberculous mycobacteria was identified during the diagnosis of the pulmonary masses. The pulmonary metastases of HCC were treated with a combination of angiotherapy, radiation therapy, and radiofrequency ablation. The patient showed a satisfactory progress with this multidisciplinary localized treatment. We report the clinical progress and review the recent literature regarding the treatment of pulmonary metastasis without intrahepatic HCC herein. (J Liver Cancer 2019;19:79-84)

Prevalence and factors associated with nontuberculous mycobacteria in non-cystic fibrosis bronchiectasis: a multicenter observational study.

BackgroundData on the prevalence of and factors associated with nontuberculous mycobacteria (NTM) in patients with non–cystic fibrosis (CF) bronchiectasis are limited. Our aim was to determine the prevalence and factors associated with isolation of NTM in this population.MethodsWe performed a multicenter observational study of historical cohorts comprising consecutive patients with non-CF bronchiectasis and at least 2 sputum samples cultured for mycobacteria over a period of 5 years.ResultsThe study population included 218 adult patients (61.9 % women) with a mean (SD) age of 55.7 (16) years and a mean (SD) of 5.1 (3.3) cultures/patient. NTM was isolated from sputum in 18 patients (8.3 %). Of these, 5 patients (28 %) met the American Thoracic Society criteria for NTM disease. Mycobacterium avium complex was the most frequently isolated microorganism (9 patients, 4.1 %). The variables independently associated with isolation of NTM were FVC ≥ 75 % predicted (OR, 4.84; 95 % CI 1.47 to 15.9; p < 0.05), age ≥ 50 years (OR, 4.74; 95 % CI 1.25 to 17.97; p < 0.05), and body mass index (BMI) ≤ 23 kg/m2 (OR, 2.97; 95 % CI 1.03-8.58; p < 0.05). Patients with these three characteristics had a 40 % probability of having at least one isolation of NMT.ConclusionsA significant number of patients with non-CF bronchiectasis are positive for the isolation of NTM. M. avium complex is the most frequently isolated mycobacteria. FVC ≥ 75 % predicted, age ≥ 50 years, and a BMI ≤ 23 kg/m2 were independently associated with the presence of NTM in patients with non-CF bronchiectasis.

Identification of Non-tuberculous mycobacteria isolated from patients at Teaching Hospitals, Kandy and Peradeniya

Introduction Non-tuberculous mycobacteria (NTM) are known to cause opportunistic nosocomial infections. The aim of the study was to identify NTM using culture characteristics, biochemical and molecular methods (multiplex PCR) from stored mycobacteria isolated from patients presenting with pulmonary and extra-pulmonary tuberculosis at Teaching Hospitals, Kandy and Peradeniya during a 4-year period from 2004 to 2009. Methods Forty mycobacterial isolates obtained from 48 samples of sputum, urine, broncho-alveolar lavage and peritoneal fluid were analyzed initially by growth characteristics, followed by biochemical and molecular methods for the presence of NTM. Five main growth characteristics were analyzed, which included rate of growth, growth-temperature relationship, production of pigment, colony morphology and growth on McConkey agar. Species identification of these NTM isolates was by performing biochemical tests. Molecular identification was performed by multiplex-PCR technique on mycobacterial clinical isolates for the rapid identification of NTM. Results Of the 40 mycobacterial isolates, 10 were identified as NTM by using culture characteristics and multiplex PCR. All the NTM isolates were identified to species level by biochemical methods and eight species of NTM were identified. These species, obtained from sterile as well as non-sterile clinical samples were identified as M. scrofulaceum, M. haemophilum, M. chelonae, M. kansasii, M. phlei, M. flavescens, M. gastri and M. vaccae. Conclusion Non-tuberculous mycobacteria were isolated from a wide range of sterile and non-sterile clinical samples and contributed to 25% of the mycobacterial isolates in this study. The results of culture characteristics were compatible with the molecular identification (multiplex PCR) differentiating Mycobacterium tuberculosis from non-tuberculous mycobacterial strains. M. kansasii and M. gastri were the most common NTM isolated from clinical isolates.

Epidemiology of nontuberculous mycobacteria (NTM) amongst individuals with cystic fibrosis (CF)

BackgroundInfection by nontuberculous mycobacteria (NTM) in patients with cystic fibrosis (CF) is often associated with significant morbidity. Limited, conflicting results are published regarding risk factors for pulmonary NTM disease. We analysed factors potentially associated with NTM in a large population of European patients with CF. MethodsWe investigated associations between presence of NTM and various factors for patients registered in the European Cystic Fibrosis Society Patient Registry. Results374 (2.75%) of 13,593 patients studied had at least one positive NTM culture within the study year. Age- and FEV1-adjusted odds of NTM infection was more than 2.5 times higher (95%CI: 1.79; 3.60) in patients infected by Stenotrophomonas maltophilia than in patients not infected (p<0.0001), 2.36 times higher (95%CI: 1.80;3.08) in patients with ABPA than without (p<0.0001), 1.79 times higher (95%CI: 1.34; 2.38) in patients who use bronchodilators than in patients who don't (p<0.0001), 1.49 times higher (95%CI: 1.18; 1.89) in patients who use inhaled antibiotics than in patients who don't (p=0.001), and 1.30 times higher (95%CI: 1.02; 1.66) in patients who use rhDNase than in patients who don't (p=0.032). ConclusionsNTM-positive cultures in individuals with CF are associated with distinct clinical variables. Improved data collection identifying risk factors for NTM infection will allow more focused screening strategies, and influence therapeutic choices and infection control measures in high-risk patients.

Non-tuberculous mycobacteria: baseline data from three sites in Papua New Guinea, 2010-2012.

To determine the proportion of non-tuberculous mycobacteria (NTM) in samples of pulmonary tuberculosis (TB) cases from Papua New Guinea who were diagnosed using acid-fast microscopy. As part of a case detection study for TB, conducted in three provincial hospitals in Papua New Guinea, sputum samples of suspected tuberculous cases aged 15 years or older were collected from November 2010 to July 2012. Mycobacterial species isolated from sputum and grown in culture were examined to distinguish between NTM and the Mycobacterium tuberculosis complex (MTBC). NTM were detected in 4% (9/225) of sputum samples grown in culture. Five (2.2%) of them were identified as NTM only and four (1.8%) were identified as mixed cultures containing both MTBC and NTM. Four different NTM species were identified; M. fortuitum, M. intracellulare, M. terrae and M. avium. This is the first report from Papua New Guinea identifying NTM in three different locations. As NTM cannot be distinguished from M. tuberculosis through smear microscopy, the presence of NTM can lead to a false-positive diagnosis of tuberculosis. The prevalence of NTM should be determined and a diagnostic algorithm developed to confirm acid-fast bacilli in a smear as M. tuberculosis.

First evidence of amoebae-mycobacteria association in drinking water network.

Free-living amoebae are protozoa ubiquitously found in water systems. They mainly feed on bacteria by phagocytosis, but some bacterial species are able to resist or even escape this lethal process. Among these amoeba resistant bacteria are numerous members of the genus Mycobacterium. Nontuberculous Mycobacteria (NTM) are opportunistic pathogens that share the same ecological niches as amoebae. While several studies have demonstrated the ability of these bacteria to colonise and persist within drinking water networks, there is also strong suspicion that mycobacteria could use amoebae as a vehicle for protection and even replication. We investigated here the presence of NTM and FLA on a drinking water network during an all year round sampling campaign. We observed that 87.6% of recovered amoebal cultures carried high numbers of NTM. Identification of these amoeba and mycobacteria strains indicated that the main genera found in drinking water networks, that is, Acanthamoeba, Vermamoeba, Echinamoeba, and Protacanthamoeba are able to carry and likely to allow replication of several environmental and potentially pathogenic mycobacteria including M. llatzerense and M. chelonae. Direct Sanger sequencing as well as pyrosequencing of environmental isolates demonstrated the frequent association of mycobacteria and FLA, as they are part of the most represented genera composing amoebae's microbiome. This is the first time that an association between FLA and NTM is observed in water networks, highlighting the importance of FLA in the ecology of NTM.

Non-tuberculous mycobacterial disease is common in patients with non-cystic fibrosis bronchiectasis

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms. Cystic fibrosis (CF) patients are susceptible to NTM, but data about NTM in patients with non-CF bronchiectasis are limited. We conducted a retrospective, descriptive study at the University of Illinois Medical Center. All patients diagnosed with bronchiectasis (code 494) using the International Classification of Diseases, ninth revision (ICD-9), between 1999 and 2006, were identified. Clinical data including lung function, radiology studies, and presence of NTM in sputum were abstracted for those who met the study criteria. One hundred eighty-two patients were enrolled in the study. Patients were divided into two groups: bronchiectasis with NTM isolates (n = 68) and bronchiectasis without isolates (n =114), and compared for clinical characteristics and underlying diseases. Mycobacterium avium complex (MAC) was the most common isolate. Fifty-five patients (30%) met the American Thoracic Society criteria for diagnosis of NTM disease. Gram-negative rods were commonly co-isolated. The probability of NTM isolation was significantly higher in elderly female patients (p = 0.04). Moreover, the probability of NTM isolation was significantly higher in the female group with low body mass index (BMI) (p = 0.002). NTM infections are common in non-CF bronchiectasis. MAC is the most frequently isolated NTM in these patients. There is also great variability in age and sex characteristics for NTM in non-CF bronchiectasis patients. Female patients with a low BMI are a high risk group for NTM infection in non-CF bronchiectasis. Routine screening for NTM is strongly recommended in this patient population.

Isolation of nontuberculous mycobacteria from hospital waters in Turkey

Nontuberculous mycobacteria (NTM) are ubiquitous in hot and cold water distribution systems. With molecular typing methods it was shown that water can be the source of colonization and infection with NTM. The aim of our study was the investigation of NTM in hot and cold water samples taken from various departments of two hospitals in Istanbul, Turkey. Totally, 160 water samples were examined. The temperature, pH, and free chlorine levels of water samples were measured between 10-41 °C, 6.78-7.98 and <0.3-0.5 mg/L, respectively. NTM were detected in 33 (20.6%) samples. Totally 20 (60.6%), 10 (30.3%) and 3 (9.1%) isolates were identified as Mycobacterium lentiflavum, Mycobacterium gordonae, and Mycobacterium peregrinum, respectively. M. lentiflavum, which was the most frequently isolated NTM, is characterized by multiple resistance to antimycobacterial drugs. Although no infections with this mycobacterium were reported from our country so far, preventive measures may be considered in patients under immunosuppression. Because no significant correlations were found among the presence of NTM or species distribution and water temperature, pH or free chlorine levels, other factors need to be investigated.

Prevalence and Concentration of Non-tuberculous Mycobacteria in Cooling Towers by Means of Quantitative PCR: A Prospective Study

There is an increasing level of interest in non-tuberculous mycobacteria (NTM) due to the increasing reported rates of diseases caused by them. Although it is well known that NTM are widely distributed in the environment it is necessary to identify its reservoirs to prevent possible infections. In this study, we aimed to investigate the occurrence and levels of NTM in cooling towers to provide evidences for considering these settings as possible sources of respiratory infections. In the current study, we detected and quantified the presence of NTM by means of a rapid method in water samples taken from 53 cooling towers of an urban area (Barcelona, Spain). A genus-specific quantitative PCR (Q-PCR) assay with a quantification limit (QL) of 500 cells l(-1) was used. 56% (30) of samples were positive with a concentration range from 4.6 × 10(3) to 1.79 × 10(6) cells l(-1). In some cases (9/30), samples were positive but with levels below the QL. The colonization rate confirmed that cooling towers could be considered as a potential reservoir for NTM. This study also evaluated Q-PCR as a useful method to detect and quantify NTM in samples coming from environmental sources.

Positive Skin and Serologic Test Results of Diagnostic Assays for Bovine Tuberculosis and Subsequent Isolation of Mycobacterium interjectum in a Pygmy Hippopotamus (Hexaprotodon liberiensis)

A 20-yr-old male pygmy hippopotamus (Hexaprotodon liberiensis), weighing 250 kg, arrived at Zoological Society London Whipsnade Zoo (United Kingdom) from a captive collection in Portugal. A quarantine health check was performed including a comparative intradermal tuberculosis (IDTB) test. Assessment of the comparative IDTB test at 72 hr revealed a strong positive reaction at the bovine site. Serum was tested with a rapid immunochromatographic assay (TB STAT-PAK) and was positive for tuberculosis antibodies. The tuberculosis tests were repeated 6 wk later with the same positive test outcome. In addition, a broncho-alveolar lavage (BAL) was submitted for mycobacterial culture. The positive IDTB test and TB STAT-PAK results were supported by multiantigen print immunoassay (MAPIA). Based on these results, the animal was suspected to be infected with Mycobacterium tuberculosis complex organisms and was euthanized. No gross or histologic signs of tuberculosis were found at postmortem examination. Mycobacterium interjectum was cultured from the BAL but not from necropsy samples. The antigens used in the TB STAT-PAK and MAPIA tests are reportedly specific for the M. tuberculosis complex, and so it is possible this animal presented with a latent case of tuberculosis or had a previous tuberculosis infection that resolved prior to testing. Cross-reactions with nontuberculous mycobacteria have been described with TB STAT-PAK and MAPIA tests. However, Western blotting analysis using serum from this animal did not recognize M. interjectum proteins of equivalent size to the M. tuberculosis-Mycobacterium bovis proteins recognized in the MAPIA. Thus, antigenic cross-reactivity with M. interjectum can be deemed less likely, but other nontuberculous mycobacterial proteins cannot be ruled out. It is therefore possible that false-positive reactions were obtained. These results highlight the difficulty of diagnosing tuberculosis in the absence of pathology and the presence of nontuberculous mycobacteria.

Clinical significance of isolation of nontuberculous mycobacteria in pulmonary tuberculosis patients

Clinical significance of isolation of nontuberculous mycobacteria (NTM) from respiratory specimens in patients with pulmonary tuberculosis is unknown. This study aimed to investigate the prevalence and clinical impact of NTM in pulmonary tuberculosis patients. We retrospectively reviewed data of patients with culture-confirmed pulmonary tuberculosis from 2000 to 2006. Those in whom NTM were isolated from respiratory specimens collected within two months before and nine months after the index culture of tuberculosis was plated were compared with those without NTM. Patients were followed for one year after initiation of anti-tuberculous treatment. Among 2133 patients with pulmonary tuberculosis, 48 (2.3%) with multiple and 106 (5.0%) with one isolate(s) of NTM were identified. Another 144 without NTM were selected and compared. The one-year mortality rates were similar among three groups. Patients with multiple NTM isolates were more likely to be symptomatic, sought medical help earlier, had smear-positive respiratory specimens, and received anti-tuberculous treatment later than those with single/no isolate(s). Cavities were more commonly visualized radiographically in patients with multiple/single NTM isolate(s) than those without NTM isolates. The mean duration of anti-tuberculous treatment was 8.8 months for patients with multiple NTM isolates, significantly longer than that in patients with single (7.6 months) and no NTM isolate(s) (7.5 months). NTM were present in the respiratory tract of 7.3% of patients with pulmonary tuberculosis. Although the outcomes were similar, the presence of NTM was associated with different clinical manifestations and had a significant impact on the treatment of tuberculosis.

Micobactérias atípicas em doentes sem síndroma de imunodeficiência adquirida

Nontuberculous mycobacteria (NTM) play an increasingly significant pathogenic role in HIV-positive patients, in patients with chronic lung disease, in other chronic conditions and in the elderly.Aims: Evaluate the importance of NTM isolation in respiratory samples in patients without HIV-infection.Methods: Retrospective evaluation of our hospital patients with no known AIDS, with at least one NTM positive respiratory sample, from 1997-2004.Results: We found 102 patients, with a median age of 63 years; 67% male. Sixty-three (62%) had underlying lung disease, mainly tuberculosis sequelae (n=19). The majority (47%) of the isolations were Mycobacterium avium complex (MAC).A diagnosis of Mycobacterium pulmonary disease was made in 16 patients (15.7%), 14 of which met the American Thoracic Society diagnostic criteria. Ten male and 6 female; median age 65 years. Twelve had underlying lung disease. All of them had respiratory infection complaints. Chest X-rays showed mainly pulmonary infiltrates, linear opacities and cavitation. MAC was the cause of mycobacterium respiratory disease in 12 patients (75%).Conclusion: NTM isolation did not equal pulmonary NTM disease in the majority of cases, even in patients with underlying lung disease. MAC was the most commonly isolated agent and its relative importance was higher in the presence of NTM disease.Rev Port Pneumol 2008; XIV (3): 323-337