The transition to Xpert MTB/RIF ultra: diagnostic accuracy for pulmonary tuberculosis in Kampala, Uganda.

BACKGROUND: The World Health Organization (WHO) has endorsed the next-generation Xpert MTB/RIF Ultra (Ultra) cartridge, and Uganda is currently transitioning from the older generation Xpert MTB/RIF (Xpert) cartridge to Ultra as the initial diagnostic test for pulmonary tuberculosis (TB). We assessed the diagnostic accuracy of Ultra for pulmonary TB among adults in Kampala, Uganda. METHODS: We sampled adults referred for Xpert testing at two hospitals and a health center over a 12-month period. We enrolled adults with positive Xpert and a random 1:1 sample with negative Xpert results. Expectorated sputum was collected for Ultra, and for solid and liquid culture testing for Xpert-negative patients. We measured sensitivity and specificity of Ultra overall and by HIV status, prior history of TB, and hospitalization, in reference to Xpert and culture results. We also assessed how classification of results in the new "trace" category affects Ultra accuracy. RESULTS: Among 698 participants included, 211 (30%) were HIV-positive and 336 (48%) had TB. The sensitivity of Ultra was 90.5% (95% CI 86.8-93.4) and specificity was 98.1% (95% CI 96.1-99.2). There were no significant differences in sensitivity and specificity by HIV status, prior history of TB or hospitalization. Xpert and Ultra results were concordant in 670 (96%) participants, with Ultra having a small reduction in specificity (difference 1.9, 95% CI 0.2 to 3.6, p=0.01). When "trace" results were considered positive for all patients, sensitivity increased by 2.1% (95% CI 0.3 to 3.9, p=0.01) without a significant reduction in specificity (- 0.8, 95% CI - 0.3 to 2.0, p=0.08). CONCLUSIONS: After 1 year of implementation, Ultra had similar performance to Xpert. Considering "trace" results to be positive in all patients increased case detection without significant loss of specificity. Longitudinal studies are needed to compare the benefit of greater diagnoses to the cost of overtreatment.

Accuracy and incremental yield of urine Xpert MTB/RIF Ultra versus Determine TB-LAM for diagnosis of pulmonary tuberculosis.

The performance of urine Xpert MTB/RIF Ultra (Xpert Ultra) for pulmonary TB diagnosis is unknown. HIV-positive and HIV-negative adults were enrolled at two health facilities in Kampala, Uganda. We compared the accuracy of urine Xpert Ultra and Determine TB-LAM in reference to sputum-based testing (positive Xpert MTB/RIF or culture), and assessed incremental yield. Urine Xpert Ultra had low sensitivity (17.2%, 95% CI 12.3-23.2) but high specificity (98.1%, 95% CI 94.4-99.6). Sensitivity reached 50.0% (95% CI 28.2-71.8) among HIV-positive patients with CD4 <100 cells/µL. Compared to Determine TB-LAM, urine Xpert Ultra was 9.4% (95% CI 3.8-14.9, P = 0.01) more sensitive, and 17.2% (95% CI 4.5-29.8, P = 0.01) more sensitive among HIV-positive patients. However, the incremental sensitivity of urine Xpert Ultra relative to sputum Xpert MTB/RIF was only 1% (95% CI -0.9 to 2.8). Urine Xpert Ultra could be an alternative for patients with advanced HIV infection unable to produce sputum.

Transmission of multidrug-resistant tuberculosis in a low-incidence setting, Switzerland, 2006 to 2012.

The goal of the present study was to examine the transmission dynamics of multidrug-resistant tuberculosis (MDR-TB) in Switzerland. Between 2006 and 2012, a total of 49 MDR-TB cases were reported to the Swiss Federal Office of Public Health, 46 of which were of foreign origin. All 49 initial strains were evaluated by molecular epidemiologic methods at the Swiss National Reference Centre for Mycobacteria. In 43 strains, unique DNA fingerprint patterns were identified. Twelve strains were grouped into six clusters. Data from contact tracing suggest likely in-country transmission in four clusters, mostly among close contacts. In the remaining two clusters, no contact tracing data were available, but the identified genotypes were known to be prevalent in the countries of origin of the patients, suggesting the possibility that the infection was acquired there. While most MDR-TB cases are imported to Switzerland, at least four of the 49 MDR-TB cases were due to transmission within the country. The imported cases, however, did not lead to secondary cases outside the circles of close contacts. The results also indicate that prevention of MDR-TB transmission among immigrants may require closer monitoring.

Stepwise implementation of a new diagnostic algorithm for multidrug-resistant tuberculosis in Haiti.

SETTING: The uptake of tests endorsed by the World Health Organization to detect and appropriately confirm multidrug-resistant tuberculosis (MDR-TB) in low-income countries remains insufficient. OBJECTIVE: To validate the implementation of line-probe assays (LPA) and liquid culture to develop an algorithm to detect MDR-TB in the challenging setting of Haiti. METHODS: Through an EXPAND-TB (Expanding Access to New Diagnostics for TB) partnership, proficiency testing and validation of 221 acid-fast bacilli positive specimens were performed. Sensitivity, cost and processing time were analysed. RESULTS: Using liquid vs. solid culture shortened the turnaround time from 54 to 19 days, with a sensitivity of 100% vs. 98.6% and a total cost reduction of 13%. LPA detected all TB and MDR-TB cases at a lower cost than culture, in a mean time of 7.5 days. CONCLUSION: The combined use of molecular and liquid culture techniques accelerates the accurate diagnosis of TB and susceptibility testing against first-line drugs in a significantly shorter time, and is less expensive. The implementation of this new algorithm could significantly and accurately improve the screening and treatment follow-up of patients affected with TB and MDR-TB.

Mediastinal mass mimicking a tumor in a patient with bladder cancer after Bacillus Calmette-Guerin treatment.

We describe the case of a 78-year-old male with bladder cancer who developed a mediastinal mass after intravesical immunotherapy with live Mycobacterium bovis BCG. The clinical diagnosis was mediastinal tumor suggestive for lymphoma. However, cultures of the biopsy specimens grew an acid-fast organism, which was identified as M. bovis BCG. To the best of our knowledge, this is the first reported case in which a post-instillation BCG infection induced a mediastinal mass that mimicked a tumor in a patient with bladder cancer.

Analysis of tuberculosis surveillance in Hungary in 2000.

SETTING: Hungary, Central Europe, with a population of 10.3 million living in 20 administrative districts (19 counties and the capital). OBJECTIVE: To summarize the results of the first year of the revised National Tuberculosis Surveillance System. DESIGN: Retrospective survey of the National Tuberculosis Surveillance Center (NTSC) database. METHODS: Analysis of data on all tuberculosis cases reported to the NTSC in 2000. Drug susceptibility results were evaluated in line with WHO and IUATLD definitions. RESULTS: During 2000, a total of 3598 patients with tuberculosis were reported. Only 40% of these were bacteriologically confirmed. Although susceptibility testing has been required for previously untreated culture-positive cases, only 801 (67.8% of the bacteriologically confirmed cases) were tested in 2000. Drug resistance was detected in 10.7% of previously untreated and in 23.5% of previously treated patients. Multidrug-resistant (MDR) cases were not common: only 1.5% of the isolates from previously untreated patients and 4.9% of those from previously treated patients were MDR. CONCLUSIONS: The results suggest that the NTSC should work towards increasing the numbers of cases that are bacteriologically confirmed. In addition, some form of surveillance system should be instituted to ensure that mandatory susceptibility testing is performed on all isolates from previously untreated tuberculosis patients.

[Routine direct detection of Mycobacterium tuberculosis with a rapid test of polymerase chain reaction applied to a Hungarian patient population]. / A Mycobacterium tuberculosis komplex direkt kimutatására szolgáló polimeráz láncreakción alapuló gyorsteszt rutinszerú alkalmazása magyarországi betegpopuláción.

The results of the present study, based on 1869 examined clinical specimens of 543 patients, represent the Hungarian parameters of a PCR test. By using the final and resolved results, the clinical sensitivity, specificity, positive and negative predictive values were 83.8%, 99.2%, 95.4% and 97%, respectively for PCR, 63.5%, 100%, 100% and 93.5%, respectively for culture, and 16.2%, 100%, 100% and 86.3%, respectively for Ziehl-Neelsen (ZN) staining. These results are essential to allow Hungarian clinicians to interpret PCR results in accordance with local conditions. The present study has demonstrated a high sensitivity (PCR vs. culture and smear, p < 0.01) and an excellent specificity of PCR. Our results indicate that the majority of M. tuberculosis-positive specimens can be identified rapidly with the test and, because of the high negative predictive value, the PCR test can help to exclude tuberculosis from the differential diagnosis in 24 hours. Moreover, the PCR can detect the presence of M. tuberculosis in 66.6% of ZN-negative and subsequently culture-positive specimens at the time of admission. The results of PCR must be interpreted with extreme caution, and the procedure is recommended only for laboratories, which simultaneously perform culture and microscopy for control of the performance of PCR tests.

The molecular basis of resistance to isoniazid, rifampin, and pyrazinamide in Mycobacterium tuberculosis.

Multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have emerged worldwide. In many countries and regions, these resistant strains constitute a serious threat to the efficacy of tuberculosis control programs. An important element in gaining control of this epidemic is developing an understanding of the molecular basis of resistance to the most important antituberculosis drugs: isoniazid, rifampin, and pyrazinamide. On the basis of this information, more exacting laboratory testing, and ultimately more appropriate and timely treatment regimens, can be developed.

Molecular characterization of rifampin-resistant isolates of Mycobacterium tuberculosis from Hungary by DNA sequencing and the line probe assay.

Two regions of rpoB associated with rifampin resistance were sequenced in 29 rifampin-resistant (determined by the proportion method) isolates of Mycobacterium tuberculosis obtained from patients from three counties in Hungary. Of the 29 resistant strains, 27 had a mutation in either the 81-bp region (26 strains) or the N-terminal region (1 strain), while the other 2 strains had no mutations in either region. The locations and frequencies of the mutations differed from those previously reported. The most common mutation in this study, D516V, was found in 38% of the Hungarian strains, a frequency 2 to 10 times higher than that found in studies from other countries. These same 29 isolates were also evaluated with the Inno-LiPA Rif. TB test (LiPA), a reverse hybridization assay for the rapid detection of rifampin resistance. Although LiPA detected the presence of an rpoB mutation in 26 of the resistant isolates, the type of mutation could not be determined in 4 isolates because the mutations present were not among those included on the LiPA strip. In addition, a silent mutation in one of the rifampin-susceptible control strains was interpreted as rifampin resistant by LiPA. These findings demonstrate the importance of validating this rapid molecular test by comparison with DNA sequence results in each geographic location before incorporating the test into routine diagnostic work.

False-positive results for Mycobacterium celatum with the AccuProbe Mycobacterium tuberculosis complex assay.

Mycobacterium celatum type 1 was found to cross-react in the AccuProbe Mycobacterium tuberculosis complex assay. Subsequently, we found a statistically significant increase in the relative light units with lower temperatures, suggesting that it is necessary to perform this AccuProbe assay at between 60 and 61 degrees C. We also recommend the inclusion of M. celatum type 1 as a negative control.

Comparison of recoveries of mycobacterium tuberculosis using the automated BACTEC MGIT 960 system, the BACTEC 460 TB system, and Löwenstein-Jensen medium.

Using two different liquid media and one conventional solid medium, a total of 57 mycobacterial isolates (Mycobacterium tuberculosis, n = 55; nontuberculous mycobacteria, n = 2) were recovered from 377 clinical specimens. The rates of recovery of M. tuberculosis were 96. 4% with the BACTEC MGIT 960 liquid medium, 92.7% with BACTEC 12B liquid medium, and 81.8% with the Löwenstein-Jensen (LJ) medium. The mean time to detection of M. tuberculosis in smear-positive specimens was 12.6 days for BACTEC MGIT 960 medium, 13.8 days for BACTEC 12B medium, and 20.1 days for LJ medium, and in smear-negative specimens it was 15.8 days for BACTEC MGIT 960 medium, 17.7 days for BACTEC 12B medium, and 42.2 days for LJ medium. The rates of contamination were 3.7, 2.9, and 1.2% for the BACTEC MGIT 960, BACTEC 12B, and LJ media, respectively. In conclusion, the nonradiometric, fully automated 7-ml BACTEC MGIT 960 system can be considered a viable alternative to the semiautomated, radiometric BACTEC 460 TB system.

Accessory function and costimulatory molecule expression of alveolar macrophages in patients with pulmonary tuberculosis.

An effective immune response against M. tuberculosis requires a coordinated interaction of alveolar macrophages (AM) and lymphocytes. Secondary signals, such as accessory function (AF) of antigen presenting cells and interaction of costimulatory molecules are also important for T cell activation. In the present study we determined the AF and the expression of CD11a, CD54, CD58, CD80, CD86 and HLA-DR costimulatory molecules by AMs lavaged from patients with pulmonary tuberculosis and controls. We hypothesized that alterations in AF and costimulatory molecule expression may influence the presentation of tuberculosis. Therefore these parameters were also correlated with the radiographic extension of the disease. AMs of patients with tuberculosis exhibited an increased AF and a significantly increased expression of co-stimulatory molecules compared with controls. Furthermore, we observed that the expression of CD54 (ICAM-1) decreased with the course of the disease. We conclude that the infection by M. tuberculosis results in an increased AF of AMs and the activity of AMs remains uninfluenced by the extension of the disease. Clear-cut changes of patterns of costimulatory molecule expression by AMs could not be observed with the progression of tuberculosis.

Polymorphisms at position -308 in the promoter region of the TNF-alpha and in the first intron of the TNF-beta genes and spontaneous and lipopolysaccharide-induced TNF-alpha release in sarcoidosis.

TNF-alpha is a potent pro-inflammatory cytokine. Previous studies have proved that biallelic polymorphisms in the TNF-alpha (-308, TNFA) and TNF-beta genes (intron 1, TNFB) influence TNF-alpha production. In sarcoidosis, a chronic granulomatous disease, as a result of an unknown in vivo activation bronchoalveolar lavage (BAL) cells release high amounts of TNF-alpha, spontaneously and after in vitro stimulation. Thus, sarcoidosis could serve as a model to test the in vivo effect of TNF gene polymorphisms. We determined the TNFA and TNFB polymorphisms of 44 patients with sarcoidosis and found the following allele frequencies: 0.80, 0.20, 0.38 and 0.62 for TNFA1, TNFA2, TNFB1 and TNFB2, respectively. To examine the in vivo effect of the named polymorphisms on the TNF-alpha production, the spontaneous and LPS-induced TNF-alpha release of BAL cells and peripheral blood mononuclear cells were also determined in patients with sarcoidosis. Statistical analysis did not reveal any significant difference between sarcoidosis patients with different genotypes. The results show that TNFA and TNFB polymorphisms do not determine the level of TNF-alpha release of mononuclear cells activated during the course of sarcoid inflammation.

Different cytokine patterns correlate with the extension of disease in pulmonary tuberculosis.

The relative amounts of different pro- and anti-inflammatory cytokines released at the site of infection by bronchoalveolar lavage (BAL) cells may influence the presentation of tuberculosis. To investigate this hypothesis the in situ release by BAL cells of the following cytokines was measured and correlated with the chest X-ray findings of 43 patients with pulmonary tuberculosis: interleukin (IL)-8, macrophage inflammatory protein-1alpha (MIP-1alpha), IL-6, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), interferon-gamma (IFN-gamma), IL-2, IL-4 and IL-5. The release of IL-8 and IL-6 decreased with the progression of the disease, while the release of MIP-1alpha was increased in patients with advanced tuberculosis. The release of TNF-alpha and TGF-beta did not differ between patients with or without cavitary lesions. The Th1 (IFN-gamma and IL-2) and Th2 (IL-4 and IL-5) cytokine release exhibited a gradual increment with the advance of tuberculosis. Thus, our data provide evidence that a Th0 cytokine pattern is predominant at the site of pulmonary tuberculosis. In conclusion, immunoparalysis status could not be observed in our patients with severe tuberculosis.

Application of a computer-directed automated microscope in mycobacteriology.

Microscopy is currently the fastest, cheapest and most easily performed technique in mycobacteriology; it can be used in any laboratory. However, the sensitivity of microscopy is unsatisfactory and it is time-consuming. To eliminate these drawbacks, we have constructed a computer-directed automated microscope. To evaluate the equipment, we examined a total of 132 smears of sputum and 74 smears of liquid media. Manual microscopy was positive for 53 and negative for 79 sputum smears, while automated microscopy was positive for 55 and negative for 77 sputum smears. Both methods furnished 50 positive and 24 negative smears of liquid media. We conclude that the automated microscope is able to detect acid-fast bacteria, the examination procedure with the instrument is more rapid (1.8-3.5 min/slide) and it is always possible to follow the standard recommendations of microscopy.

Comparison of the mycobacteria growth indicator tube with MB redox, Löwenstein-Jensen, and Middlebrook 7H11 media for recovery of mycobacteria in clinical specimens.

The rate of recovery and the mean time to detection of mycobacteria in clinical specimens were evaluated with two nonradiometric broth-based systems, the Mycobacteria Growth Indicator Tube (MGIT) and MB Redox systems. The data obtained for each system were compared with each other and with those obtained with the Löwenstein-Jensen (LJ) and Middlebrook 7H11 reference media. A total of 117 mycobacterial isolates (Mycobacterium tuberculosis, n = 112; nontuberculous mycobacteria, n = 5) were detected in 486 clinical specimens. The recovery rates for M. tuberculosis were 91 of 112 (81.3%) isolates with MGIT and 81 of 112 (72.3%) isolates with MB Redox. The combination of MGIT plus MB Redox recovered 104 of the 112 (92.9%) M. tuberculosis isolates. MGIT plus LJ plus Middlebrook 7H11 recovered 106 of the 112 (94.6%) isolates, MB Redox plus LJ plus Middlebrook 7H11 recovered 99 of the 112 (88.4%) isolates, and LJ plus Middlebrook 7H11 recovered 84 of the 112 (75. 0%) isolates. The mean time to detection of M. tuberculosis in smear-positive specimens was 7.2 days with MGIT, 6.9 days with MB Redox, 20.4 days with LJ, and 17.6 days with Middlebrook 7H11. The mean time to detection of M. tuberculosis in smear-negative specimens was 19.1 days with MGIT, 15.5 days with MB Redox, 25.8 days with LJ, and 21.6 days with Middlebrook 7H11. The contamination rates were 4.4, 3.8, 2.1, and 2.7% for MGIT, MB Redox, LJ, and Middlebrook 7H11, respectively. In conclusion, MGIT and MB Redox can be viable tools in the routine mycobacteriology laboratory.

[Pulmonary echinococcosis]. / Pulmonalis echinococcosis.

Two patients with pulmonal Echinococcosis are presented by the authors. Contact with cestoda carrier animals cannot be revealed. At the first patient, who was without any complaints, the two round shadows in her chest X-ray were detected accidentally by screening examination and before the operation only eosinophilia, many eosinophil granulocytes in the pleural effusion and the positive complement binding reaction were related to the Echinococcosis, which was proved by the histological examination of the intraoperative biopsy. The other patient had complaints during months. In this case the Echinococcus granulosus broke into the bronchus and emptied in the sputum. Postoperative histological diagnosis can be obtained by help of the excision from the intraluminal alteration which was visible during bronchoscopy. The authors summarize the etiology, the clinical signs, the diagnose and the therapy of Echinococcosis. They call attention to the incidence of this mainly tropical disease in Hungary and to the rare soliter pulmonal manifestation of the Echinococcosis.