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Search Results: 1 - 10 of 192663 matches for " Kathleen D. Eisenach "
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Evaluation of Capilia TB assay for rapid identification of Mycobacterium tuberculosis complex in BACTEC MGIT 960 and BACTEC 9120 blood cultures
Christopher Muchwa, Joseph Akol, Alfred Etwom, Karen Morgan, Patrick Orikiriza, Francis Mumbowa, Paul R Odong, David P Kateete, Kathleen D Eisenach, Moses L Joloba
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-44
Abstract: One thousand samples from pulmonary and disseminated tuberculosis (TB) suspects admitted to the JCRC clinic and the TB wards at Old Mulago hospital in Kampala, Uganda, were cultured in automated BACTEC MGIT 960 and BACTEC 9120 blood culture systems. BACTEC-positive samples were screened for purity by sub-culturing on blood agar plates. Two hundred and fifty three (253) samples with Acid fast bacilli (AFB, 174 BACTEC MGIT 960 and 79 BACTEC 9120 blood cultures) were analyzed for presence of MTC using Capilia TB and in-house PCR assays.The overall Sensitivity, Specificity, Positive and Negative Predictive values, and Kappa statistic for Capilia TB assay for identification of MTC were 98.4%, 97.6%, 97.7%, 98.4% and 0.96, respectively. Initially, the performance of in-house PCR on BACTEC 9120 blood cultures was poor (Sensitivity, Specificity, PPV, NPV and Kappa statistic of 100%, 29.3%,7%, 100% and 0.04, respectively) but improved upon sub-culturing on solid medium (Middlebrook 7H10) to 100%, 95.6%, 98.2%, 100% and 0.98, respectively. In contrast, the Sensitivity and Specificity of Capilia TB assay was 98.4% and 97.9%, respectively, both with BACTEC blood cultures and Middlebrook 7H10 cultured samples, revealing that Capilia was better than in-house PCR for identification of MTC in blood cultures. Additionally, Capilia TB was cheaper than in-house PCR for individual samples ($2.03 vs. $12.59, respectively), and was easier to perform with a shorter turnaround time (20 min vs. 480 min, respectively).Capilia TB assay is faster and cheaper than in-house PCR for rapid identification of MTC from BACTEC MGIT 960 and BACTEC 9120 culture systems in real-time testing of AFB positive cultures.Genetically related species of the Mycobacterium tuberculosis complex (MTC; M. tuberculosis, M. bovis, M. bovis BCG, M. africanum, M. caprae and M. cannetti) cause tuberculosis (TB) [1], a global disease that affects one third of the human population [2,3]. Tuberculosis and HIV form a deadly s
Rhomboid homologs in mycobacteria: insights from phylogeny and genomic analysis
David P Kateete, Moses Okee, Fred A Katabazi, Alfred Okeng, Jeniffer Asiimwe, Henry W Boom, Kathleen D Eisenach, Moses L Joloba
BMC Microbiology , 2010, DOI: 10.1186/1471-2180-10-272
Abstract: Many mycobacterial genomes contained two phylogenetically distinct active rhomboids orthologous to Rv0110 (rhomboid protease 1) and Rv1337 (rhomboid protease 2) of Mycobacterium tuberculosis H37Rv, which were acquired independently. There was a genome-wide conservation and organization of the orthologs of Rv1337 arranged in proximity with glutamate racemase (mur1), while the orthologs of Rv0110 appeared evolutionary unstable and were lost in Mycobacterium leprae and the Mycobacterium avium complex. The orthologs of Rv0110 clustered with eukaryotic rhomboids and contained eukaryotic motifs, suggesting a possible common lineage. A novel nonsense mutation at the Trp73 codon split the rhomboid of Mycobacterium avium subsp. Paratuberculosis into two hypothetical proteins (MAP2425c and MAP2426c) that are identical to MAV_1554 of Mycobacterium avium. Mycobacterial rhomboids contain putative rhomboid catalytic signatures, with the protease active site stabilized by Phenylalanine. The topology and transmembrane helices of the Rv0110 orthologs were similar to those of eukaryotic secretase rhomboids, while those of Rv1337 orthologs were unique. Transcription assays indicated that both mycobacterial rhomboids are possibly expressed.Mycobacterial rhomboids are active rhomboid proteases with different evolutionary history. The Rv0110 (rhomboid protease 1) orthologs represent prokaryotic rhomboids whose progenitor may be the ancestors of eukaryotic rhomboids. The Rv1337 (rhomboid protease 2) orthologs appear more stable and are conserved nearly in all mycobacteria, possibly alluding to their importance in mycobacteria. MAP2425c and MAP2426c provide the first evidence for a split homologous rhomboid, contrasting whole orthologs of genetically related species. Although valuable insights to the roles of rhomboids are provided, the data herein only lays a foundation for future investigations for the roles of rhomboids in mycobacteria.The genus Mycobacterium consists of ~148 species [1
Use of in-house PCR for identification of Mycobacterium tuberculosis in BACTEC broth cultures of respiratory specimens
Gouveia, Ana Cláudia Carvalho;Eisenach, Kathleen D.;Vinhas, Solange Alves;Ribeiro, Fabiola Karla Corrêa;Peres, Renata Lyrio;Dietze, Reynaldo;Hadad, David Jamil;Palaci, Moisés;
Memórias do Instituto Oswaldo Cruz , 2008, DOI: 10.1590/S0074-02762008000400012
Abstract: we evaluated the ability of a pcr assay to identify mycobacterium tuberculosis complex (mtbc) from positive bactec? 12b broth cultures. a total of 107 sputum samples were processed and inoculated into ogawa slants and bactec? 12b vials. at a growth index (gi) > 30, 1.0 ml of the 12b broth was removed, stored, and assayed with pcr. molecular results were compared to those obtained by phenotypic identification methods, including the bactec? nap method. the average times required to perform pcr and nap were compared. of the 107 broth cultures evaluated, 90 were nap positive, while 91 were pcr positive for mtbc. of particular interest were three contaminated bactec? 12b broth cultures yielding microorganisms other than acid-fast bacilli growth with a mtbc that were successfully identified by pcr, resulting in a mean time of 14 days to identify mtbc before nap identification. these results suggest that pcr could be used as an alternative to the nap test for the rapid identification of mtbc in bactec? 12b cultures, particularly in those that contained both mtbc and nontuberculous mycobacteria.
Low-cost rapid detection of rifampicin resistant tuberculosis using bacteriophage in Kampala, Uganda
Hamidou Traore, Sam Ogwang, Kim Mallard, Moses L Joloba, Francis Mumbowa, Kalpana Narayan, Susan Kayes, Edward C Jones-Lopez, Peter G Smith, Jerrold J Ellner, Roy D Mugerwa, Kathleen D Eisenach, Ruth McNerney
Annals of Clinical Microbiology and Antimicrobials , 2007, DOI: 10.1186/1476-0711-6-1
Abstract: In a blinded study 149 M. tuberculosis isolates were tested for resistance to rifampicin by the phage assay and results compared to those from routine phenotypic testing in BACTEC 460. Three concentrations of drug were used 2, 4 and 10 μg/ml. Isolates found resistant by either assay were subjected to sequence analysis of a 81 bp fragment of the rpoB gene to identify mutations predictive of resistance. Four isolates with discrepant phage and BACTEC results were tested in a second phenotypic assay to determine minimal inhibitory concentrations.Initial analysis suggested a sensitivity and specificity of 100% and 96.5% respectively for the phage assay used at 4 and 10 μg/ml when compared to the BACTEC 460. However, further analysis revealed 4 false negative results from the BACTEC 460 and the phage assay proved the more sensitive and specific of the two tests. Of the 39 isolates found resistant by the phage assay 38 (97.4%) were found to have mutations predictive of resistance in the 81 bp region of the rpoB gene. When used at 2 μg/ml false resistant results were observed from the phage assay. The cost of reagents for testing each isolate was estimated to be 1.3US$ when testing a batch of 20 isolates on a single 96 well plate. Results were obtained in 48 hours.The phage assay can be used for screening of isolates for resistance to rifampicin, with high sensitivity and specificity in Uganda. The test may be useful in poorly resourced laboratories as a rapid screen to differentiate between rifampicin susceptible and potential MDR-TB cases.The emergence of drug resistant strains of Mycobacterium tuberculosis is of growing concern. Multi-drug resistant disease (MDR-TB), where the strain is resistant to both the major anti-tuberculosis drugs rifampicin and isoniazid, has been reported in all regions of the world. Incidences of MDR exceeding 10% of TB caseloads have been reported in parts of Central Asia, China, Eastern Europe, Russia and Africa [1]. The prognosis of patients
Comparison of rapid tests for detection of rifampicin-resistant Mycobacterium tuberculosis in Kampala, Uganda
Sam Ogwang, Benon B Asiimwe, Hamidou Traore, Francis Mumbowa, Alphonse Okwera, Kathleen D Eisenach, Susan Kayes, Edward C Jones-López, Ruth McNerney, William Worodria, Irene Ayakaka, Roy D Mugerwa, Peter G Smith, Jerrold Ellner, Moses L Joloba
BMC Infectious Diseases , 2009, DOI: 10.1186/1471-2334-9-139
Abstract: Sputum specimens from re-treatment TB patients presenting to the Mulago Hospital National TB Treatment Centre in Kampala, Uganda, were examined by conventional methods and simultaneously used in one of the four direct susceptibility tests, namely direct BACTEC 460, Etest, "in-house" phage test, and INNO- Rif.TB. The reference method was the BACTEC 460 indirect culture drug susceptibility testing. Test performance, cost and turn around times were assessed.In comparison with indirect BACTEC 460, the respective sensitivities and specificities for detecting rifampicin resistance were 100% and 100% for direct BACTEC and the Etest, 94% and 95% for the phage test, and 87% and 87% for the Inno-LiPA assay. Turn around times ranged from an average of 3 days for the INNO-LiPA and phage tests, 8 days for the direct BACTEC 460 and 20 days for the Etest. All methods were faster than the indirect BACTEC 460 which had a mean turn around time of 24 days. The cost per test, including labour ranged from $18.60 to $41.92 (USD).All four rapid technologies were shown capable of detecting rifampicin resistance directly from sputum. The LiPA proved rapid, but was the most expensive. It was noted, however, that the LiPA test allows sterilization of samples prior to testing thereby reducing the risk of accidental laboratory transmission. In contrast the Etest was low cost, but slow and would be of limited assistance when treating patients. The phage test was the least reproducible test studied with failure rate of 27%. The test preferred by the laboratory personnel, direct BACTEC 460, requires further study to determine its accuracy in real-time treatment decisions in Uganda.Developing countries account for 95% of active tuberculosis (TB) cases and deaths due to TB worldwide [1,2]. In developing countries, many national TB control programs have low case detection rates and once a case is detected, cure may also be difficult because of poor case holding, high default rates and insufficient co
Effectiveness of the Standard WHO Recommended Retreatment Regimen (Category II) for Tuberculosis in Kampala, Uganda: A Prospective Cohort Study
Edward C. Jones-López equal contributor ,Irene Ayakaka equal contributor,Jonathan Levin,Nancy Reilly,Francis Mumbowa,Scott Dryden-Peterson,Grace Nyakoojo,Kevin Fennelly,Beth Temple,Susan Nakubulwa,Moses L. Joloba,Alphonse Okwera,Kathleen D. Eisenach,Ruth McNerney,Alison M. Elliott,Jerrold J. Ellner,Peter G. Smith,Roy D. Mugerwa
PLOS Medicine , 2011, DOI: 10.1371/journal.pmed.1000427
Abstract: Background Each year, 10%–20% of patients with tuberculosis (TB) in low- and middle-income countries present with previously treated TB and are empirically started on a World Health Organization (WHO)-recommended standardized retreatment regimen. The effectiveness of this retreatment regimen has not been systematically evaluated. Methods and Findings From July 2003 to January 2007, we enrolled smear-positive, pulmonary TB patients into a prospective cohort to study treatment outcomes and mortality during and after treatment with the standardized retreatment regimen. Median time of follow-up was 21 months (interquartile range 12–33 months). A total of 29/148 (20%) HIV-uninfected and 37/140 (26%) HIV-infected patients had an unsuccessful treatment outcome. In a multiple logistic regression analysis to adjust for confounding, factors associated with an unsuccessful treatment outcome were poor adherence (adjusted odds ratio [aOR] associated with missing half or more of scheduled doses 2.39; 95% confidence interval (CI) 1.10–5.22), HIV infection (2.16; 1.01–4.61), age (aOR for 10-year increase 1.59; 1.13–2.25), and duration of TB symptoms (aOR for 1-month increase 1.12; 1.04–1.20). All patients with multidrug-resistant TB had an unsuccessful treatment outcome. HIV-infected individuals were more likely to die than HIV-uninfected individuals (p<0.0001). Multidrug-resistant TB at enrolment was the only common risk factor for death during follow-up for both HIV-infected (adjusted hazard ratio [aHR] 17.9; 6.0–53.4) and HIV-uninfected (14.7; 4.1–52.2) individuals. Other risk factors for death during follow-up among HIV-infected patients were CD4<50 cells/ml and no antiretroviral treatment (aHR 7.4, compared to patients with CD4≥200; 3.0–18.8) and Karnofsky score <70 (2.1; 1.1–4.1); and among HIV-uninfected patients were poor adherence (missing half or more of doses) (3.5; 1.1–10.6) and duration of TB symptoms (aHR for a 1-month increase 1.9; 1.0–3.5). Conclusions The recommended regimen for retreatment TB in Uganda yields an unacceptable proportion of unsuccessful outcomes. There is a need to evaluate new treatment strategies in these patients. Please see later in the article for the Editors' Summary
Elucidating Emergence and Transmission of Multidrug-Resistant Tuberculosis in Treatment Experienced Patients by Whole Genome Sequencing
Taane G. Clark, Kim Mallard, Francesc Coll, Mark Preston, Samuel Assefa, David Harris, Sam Ogwang, Francis Mumbowa, Bruce Kirenga, Denise M. O’Sullivan, Alphonse Okwera, Kathleen D. Eisenach, Moses Joloba, Stephen D. Bentley, Jerrold J. Ellner, Julian Parkhill, Edward C. Jones-López, Ruth McNerney
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083012
Abstract: Background Understanding the emergence and spread of multidrug-resistant tuberculosis (MDR-TB) is crucial for its control. MDR-TB in previously treated patients is generally attributed to the selection of drug resistant mutants during inadequate therapy rather than transmission of a resistant strain. Traditional genotyping methods are not sufficient to distinguish strains in populations with a high burden of tuberculosis and it has previously been difficult to assess the degree of transmission in these settings. We have used whole genome analysis to investigate M. tuberculosis strains isolated from treatment experienced patients with MDR-TB in Uganda over a period of four years. Methods and Findings We used high throughput genome sequencing technology to investigate small polymorphisms and large deletions in 51 Mycobacterium tuberculosis samples from 41 treatment-experienced TB patients attending a TB referral and treatment clinic in Kampala. This was a convenience sample representing 69% of MDR-TB cases identified over the four year period. Low polymorphism was observed in longitudinal samples from individual patients (2-15 SNPs). Clusters of samples with less than 50 SNPs variation were examined. Three clusters comprising a total of 8 patients were found with almost identical genetic profiles, including mutations predictive for resistance to rifampicin and isoniazid, suggesting transmission of MDR-TB. Two patients with previous drug susceptible disease were found to have acquired MDR strains, one of which shared its genotype with an isolate from another patient in the cohort. Conclusions Whole genome sequence analysis identified MDR-TB strains that were shared by more than one patient. The transmission of multidrug-resistant disease in this cohort of retreatment patients emphasises the importance of early detection and need for infection control. Consideration should be given to rapid testing for drug resistance in patients undergoing treatment to monitor the emergence of resistance and permit early intervention to avoid onward transmission.
Treatment Outcomes of New Tuberculosis Patients Hospitalized in Kampala, Uganda: A Prospective Cohort Study
Bruce J. Kirenga, Jonathan Levin, Irene Ayakaka, William Worodria, Nancy Reilly, Francis Mumbowa, Helen Nabanjja, Grace Nyakoojo, Kevin Fennelly, Susan Nakubulwa, Moses Joloba, Alphonse Okwera, Kathleen D. Eisenach, Ruth McNerney, Alison M. Elliott, Roy D. Mugerwa, Peter G. Smith, Jerrold J. Ellner, Edward C. Jones-López
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090614
Abstract: Background In most resource limited settings, new tuberculosis (TB) patients are usually treated as outpatients. We sought to investigate the reasons for hospitalisation and the predictors of poor treatment outcomes and mortality in a cohort of hospitalized new TB patients in Kampala, Uganda Methods and findings Ninety-six new TB patients hospitalised between 2003 and 2006 were enrolled and followed for two years. Thirty two were HIV-uninfected and 64 were HIV-infected. Among the HIV-uninfected, the commonest reasons for hospitalization were low Karnofsky score (47%) and need for diagnostic evaluation (25%). HIV-infected patients were commonly hospitalized due to low Karnofsky score (72%), concurrent illness (16%) and diagnostic evaluation (14%). Eleven HIV uninfected patients died (mortality rate 19.7 per 100 person-years) while 41 deaths occurred among the HIV-infected patients (mortality rate 46.9 per 100 person years). In all patients an unsuccessful treatment outcome (treatment failure, death during the treatment period or an unknown outcome) was associated with duration of TB symptoms, with the odds of an unsuccessful outcome decreasing with increasing duration. Among HIV-infected patients, an unsuccessful treatment outcome was also associated with male sex (P = 0.004) and age (P = 0.034). Low Karnofsky score (aHR = 8.93, 95% CI 1.88 – 42.40, P = 0.001) was the only factor significantly associated with mortality among the HIV-uninfected. Mortality among the HIV-infected was associated with the composite variable of CD4 and ART use, with patients with baseline CD4 below 200 cells/μL who were not on ART at a greater risk of death than those who were on ART, and low Karnofsky score (aHR = 2.02, 95% CI 1.02 – 4.01, P = 0.045). Conclusion Poor health status is a common cause of hospitalisation for new TB patients. Mortality in this study was very high and associated with advanced HIV Disease and no use of ART.
The Impact of Mouse Passaging of Mycobacterium tuberculosis Strains prior to Virulence Testing in the Mouse and Guinea Pig Aerosol Models
Paul J. Converse,Kathleen D. Eisenach,Sue A. Theus,Eric L. Nuermberger,Sandeep Tyagi,Lan H. Ly,Deborah E. Geiman,Haidan Guo,Scott T. Nolan,Nicole C. Akar,Lee G. Klinkenberg,Radhika Gupta,Shichun Lun,Petros C. Karakousis,Gyanu Lamichhane,David N. McMurray,Jacques H. Grosset,William R. Bishai
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010289
Abstract: It has been hypothesized that the virulence of lab-passaged Mycobacterium tuberculosis and recombinant M. tuberculosis mutants might be reduced due to multiple in vitro passages, and that virulence might be augmented by passage of these strains through mice before quantitative virulence testing in the mouse or guinea pig aerosol models.
Secondary Attack Rate of Tuberculosis in Urban Households in Kampala, Uganda
Christopher C. Whalen,Sarah Zalwango,Allan Chiunda,LaShaunda Malone,Kathleen Eisenach,Moses Joloba,W. Henry Boom,Roy Mugerwa
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0016137
Abstract: Tuberculosis is an ancient disease that continues to threaten individual and public health today, especially in sub-Saharan Africa. Current surveillance systems describe general risk of tuberculosis in a population but do not characterize the risk to an individual following exposure to an infectious case.
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