Posts filed under ‘Micobacterias’

The Incremental Value of Repeated Induced Sputum and Gastric Aspirate Samples for the Diagnosis of Pulmonary Tuberculosis in Young Children With Acute Community-Acquired Pneumonia

Clinical Infectious Diseases June 15, 2017 V.64 Suppl.3

David P. Moore; Melissa M. Higdon; Laura L. Hammitt; Christine Prosperi; Andrea N. DeLuca …

Background.

Mycobacterium tuberculosis (Mtb) contributes to the pathogenesis of childhood acute community-acquired pneumonia in settings with a high tuberculosis burden. The incremental value of a repeated induced sputum (IS) sample, compared with a single IS or gastric aspirate (GA) sample, is not well known.

Methods.

Two IS samples were obtained for Mtb culture from children enrolled as cases in the Pneumonia Etiology Research for Child Health (PERCH) study in South Africa. Nonstudy attending physicians requested GA if pulmonary tuberculosis was clinically suspected. We compared the Mtb yield of 2 IS samples to that of 1 IS sample and GA samples.

Results. 

Twenty-seven (3.0%) culture-confirmed pulmonary tuberculosis cases were identified among 906 children investigated with IS and GA samples for Mtb. Results from 2 IS samples were available for 719 children (79.4%). Of 12 culture-confirmed pulmonary tuberculosis cases identified among children with ≥2 IS samples, 4 (33.3%) were negative at the first IS sample. In head-to-head comparisons among children with both GA and IS samples collected, the yield of 1 GA sample (8 of 427; 1.9%) was similar to that of 1 IS sample (5 of 427, 1.2%), and the yield of 2 GA samples (10 of 300; 3.3%) was similar to that of 2 IS samples (5 of 300; 1.7%). IS samples identified 8 (42.1%) of the 19 culture-confirmed pulmonary tuberculosis cases that were identified through submission of IS and GA samples.

Conclusions.

A single IS sample underestimated the presence of Mtb in children hospitalized with severe or very severe pneumonia. Detection of Mtb is enhanced by combining 2 IS with GA sample collections in young children with acute severe pneumonia.

PDF

https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/cid/64/suppl_3/10.1093_cid_cix099/5/cix099.pdf?Expires=1496600320&Signature=TIU6uc3Nu6l6ejBHfTFTMUROvfJ~1SStsVfbKHmeyh1GMGo4ekp42a-5IcoWiUswnp4DGES3~Ap5827LjXY6e0UjwS7Z0wYH8yUfjkYIg12zw09zDtXluMyr3c8HFx7L1b6vBYhbIqmQ1jAjHnhfk97cuCPlAmMJ685z16REmbHCEfLKZOMq2lQNAHeq4oeatp1aJNrBoGcfUNsjLGWTMGTWAA3LF7UgH0k0LXYeXvPtDW5feEPhi4C6-ugyTHzcvLmgXcBT0R4-zo0MV0mG0IBgj46V5TNcRjWFlWHMfU~689jWM3vDGOZqdU5tO83kxnGw4IefWgdH7WCqQS8CNQ__&Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q

 

June 3, 2017 at 2:31 pm

Rifabutin Is Active against Mycobacterium abscessus Complex

Antimicrob. Agents Chemother. June 2017 V.61 N.6

Dinah Binte Aziz, Jian Liang Low, Mu-Lu Wu, Martin Gengenbacher, Jeanette W. P. Teo, Véronique Dartois, and Thomas Dick

aDepartment of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore

bDepartment of Laboratory Medicine, National University Hospital, Singapore

cPublic Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA

Lung infections caused by Mycobacterium abscessus are emerging as a global threat to individuals with cystic fibrosis and to other patient groups. Recent evidence for human-to-human transmission worsens the situation. M. abscessus is an intrinsically multidrug-resistant pathogen showing resistance to even standard antituberculosis drugs, such as rifampin. Here, our objective was to identify existing drugs that may be employed for the treatment of M. abscessus lung disease. A collection of more than 2,700 approved drugs was screened at a single-point concentration against an M. abscessus clinical isolate. Hits were confirmed with fresh solids in dose-response experiments. For the most attractive hit, growth inhibition and bactericidal activities against reference strains of the three M. abscessus subspecies and a collection of clinical isolates were determined. Surprisingly, the rifampin derivative rifabutin had MICs of 3 ± 2 μM (3 μg/ml) against the screening strain, the reference strains M. abscessus subsp. abscessus ATCC 19977, M. abscessus subsp. bolletii CCUG 50184-T, and M. abscessus subsp. massiliense CCUG 48898-T, as well as against a collection of clinical isolates. Furthermore, rifabutin was active against clarithromycin-resistant strains. In conclusion, rifabutin, in contrast to rifampin, is active against the Mycobacterium abscessus complex bacteria in vitro and may be considered for treatment of M. abscessus lung disease.

PDF

http://aac.asm.org/content/61/6/e00155-17.full.pdf+html

May 28, 2017 at 4:54 pm

An evaluation of automated chest radiography reading software for tuberculosis screening among public- and private-sector patients

Eur Respir J ERJ May 2017 V.49 N.5

Md Toufiq Rahman, Andrew J. Codlin, Md Mahfuzur Rahman, Ayenun Nahar, Mehdi Reja, Tariqul Islam, Zhi Zhen Qin, Md Abdus Shakur Khan, Sayera Banu, and Jacob Creswell

Computer-aided reading (CAR) of medical images is becoming increasingly common, but few studies exist for CAR in tuberculosis (TB). We designed a prospective study evaluating CAR for chest radiography (CXR) as a triage tool before Xpert MTB/RIF (Xpert).

Consecutively enrolled adults in Dhaka, Bangladesh, with TB symptoms received CXR and Xpert. Each image was scored by CAR and graded by a radiologist. We compared CAR with the radiologist for sensitivity and specificity, area under the receiver operating characteristic curve (AUC), and calculated the potential Xpert tests saved.

A total of 18 036 individuals were enrolled. TB prevalence by Xpert was 15%. The radiologist graded 49% of CXRs as abnormal, resulting in 91% sensitivity and 58% specificity. At a similar sensitivity, CAR had a lower specificity (41%), saving fewer (36%) Xpert tests. The AUC for CAR was 0.74 (95% CI 0.73–0.75). CAR performance declined with increasing age. The radiologist grading was superior across all sub-analyses.

Using CAR can save Xpert tests, but the radiologist’s specificity was superior. Differentiated CAR thresholds may be required for different populations. Access to, and costs of, human readers must be considered when deciding to use CAR software. More studies are needed to evaluate CAR using different screening approaches.

FULL TEXT

http://erj.ersjournals.com/content/49/5/1602159?etoc

PDF

http://erj.ersjournals.com/content/erj/49/5/1602159.full.pdf

May 27, 2017 at 8:36 am

Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring.

Proc Natl Acad Sci USA. Apr 11, 2017 V.114 N.15 P.3969-3974.

Liu C1,2,3, Zhao Z4, Fan J1,3, Lyon CJ1,3, Wu HJ1,5, Nedelkov D6, Zelazny AM4, Olivier KN7, Cazares LH8, Holland SM9, Graviss EA10, Hu Y11,2,3.

Author information

1 Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030.

2 School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287.

3 Virginia G. Piper Biodesign Center for Personalized Diagnostics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287.

4 Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892.

5 Department of Chemical Engineering, Texas A&M University, College Station, TX 77843.

6 Molecular Biomarkers Laboratory, The Biodesign Institute, Arizona State University, Tempe, AZ 85287.

7 Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, Bethesda, MD 20892.

8 Molecular and Translational Sciences, US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702.

9 Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892.

10 Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, TX 77030.

11 Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030; tyhu@asu.edu.

Abstract

Tuberculosis (TB) is a major global health threat, resulting in an urgent unmet need for a rapid, non-sputum-based quantitative test to detect active Mycobacterium tuberculosis (Mtb) infections in clinically diverse populations and quickly assess Mtb treatment responses for emerging drug-resistant strains. We have identified Mtb-specific peptide fragments and developed a method to rapidly quantify their serum concentrations, using antibody-labeled and energy-focusing porous discoidal silicon nanoparticles (nanodisks) and high-throughput mass spectrometry (MS) to enhance sensitivity and specificity. NanoDisk-MS diagnosed active Mtb cases with high sensitivity and specificity in a case-control study with cohorts reflecting the complexity of clinical practice. Similar robust sensitivities were obtained for cases of culture-positive pulmonary TB (PTB; 91.3%) and extrapulmonary TB (EPTB; 92.3%), and the sensitivities obtained for culture-negative PTB (82.4%) and EPTB (75.0%) in HIV-positive patients significantly outperformed those reported for other available assays. NanoDisk-MS also exhibited high specificity (87.1-100%) in both healthy and high-risk groups. Absolute quantification of serum Mtb antigen concentration was informative in assessing responses to antimycobacterial treatment. Thus, a NanoDisk-MS assay approach could significantly improve the diagnosis and management of active TB cases, and perhaps other infectious diseases as well.

PDF

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5393254/pdf/pnas.201621360.pdf

May 11, 2017 at 11:28 am

Concentration-Dependent Antagonism and Culture Conversion in Pulmonary Tuberculosis

Clin Inf Dis May 15, 2017 V.64 N.10

Neesha Rockwood; Jotam G. Pasipanodya; Paolo Denti; Frederick Sirgel; Maia Lesosky

The relationship between drug concentrations, minimum inhibitory concentrations, and sputum culture conversion in tuberculosis is unclear. We identified concentration-dependent antagonism between isoniazid and rifampicin that was associated with poorer 2-month sputum conversion.

PDF

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May 6, 2017 at 3:53 pm

World Health Organization treatment guidelines for drug-resistant tuberculosis, 2016 update

European Respiratory Journal March 2017 V.49 N.3

Dennis Falzon, Holger J. Schünemann, Elizabeth Harausz, Licé González-Angulo, Christian Lienhardt, Ernesto Jaramillo, and Karin Weyer

Antimicrobial resistance is a major global concern. Tuberculosis (TB) strains resistant to rifampicin and other TB medicines challenge patient survival and public health. The World Health Organization (WHO) has published treatment guidelines for drug-resistant TB since 1997 and last updated them in 2016 based on reviews of aggregated and individual patient data from published and unpublished studies. An international expert panel formulated recommendations following the GRADE approach. The new WHO guidelines recommend a standardised 9–12 months shorter treatment regimen as first choice in patients with multidrug- or rifampicin-resistant TB (MDR/RR-TB) strains not resistant to fluoroquinolones or second-line injectable agents; resistance to these two classes of core second-line medicines is rapidly detectable with molecular diagnostics also approved by WHO in 2016. The composition of longer regimens for patients ineligible for the shorter regimen was modified. A first-ever meta-analysis of individual paediatric patient data allowed treatment recommendations for childhood MDR/RR-TB to be made. Delamanid is now also recommended in patients aged 6–17 years. Partial lung resection is a recommended option in MDR/RR-TB care. The 2016 revision highlighted the continued shortage of high-quality evidence and implementation research, and reiterated the need for clinical trials and best-practice studies to improve MDR/RR-TB patient treatment outcomes and strengthen policy.

PDF

http://erj.ersjournals.com/content/erj/49/3/1602308.full.pdf

April 12, 2017 at 8:10 am

Neumonía adquirida en la comunidad – Guía práctica elaborada por un comité intersociedades

Medicina (B. Aires) Julio/Agosto 2003 V.63 N.4

Luna C. M.1, Calmaggi A.2, Caberloto O.1, Gentile J.2, Valentín R.1, 3, Ciruzzi J.1 , Clara L.2, Rizzo O.1, Lasdica S.1, 3, Blumenfeld M.2, Benchetrit G.2, Famiglietti A.4, ApezteguIa C.1, 3, Monteverde A.1 y Grupo Argentino de Estudio de la NAC

1 Asociación Argentina de Medicina Respiratoria (AAMR),

2 Sociedad Argentina de Infectología (SADI),

3 Sociedad Argentina de Terapia Intensiva (SATI),

4 Sociedad Argentina de Bacteriología Clínica (SADEBAC), Asociación Argentina de Microbiología (AAM),

5 Sociedad Argentina de Virología (SAV),

6 Sociedad Argentina de Medicina (SAM), Buenos Aires

Resumen

Las guías para neumonía adquirida en la comunidad (NAC) contribuyen a ordenar el manejo de los pacientes. La NAC presenta cambios en su etiología, epidemiología y sensibilidad a antibióticos que obligan a la revisión periódica de las guías. Un comité intersociedades elaboró esta guía dividida en tópicos y basada en guías y estudios clínicos recientes. La NAC afecta anualmente al 1% de la población; la mayoría de los pacientes requiere atención ambulatoria, en otros reviste gravedad (representa la 6ª causa de muerte en Argentina). La etiología es diferente si el paciente es ambulatorio, requiere internación en sala general o en terapia intensiva, pero no hay forma segura de predecirla clínicamente. Los predictores de mala evolución son: edad, antecedentes personales y comorbilidades y hallazgos del examen físico, del laboratorio y de la radiografía de tórax.  Entre 10 y 25% de los pacientes que se internan deben hacerlo en terapia intensiva para ventilación mecánica o soporte hemodinámico (NAC grave), tanto inicialmente como durante su evolución. Estos pacientes presentan alta mortalidad; algunos criterios ayudan a reconocerlos. Embarazo, EPOC e internación en institutos geriátricos requieren consideraciones especiales. El diagnóstico es clínico, los métodos complementarios ayudan a determinar la etiología y la gravedad: la radiografía de tórax debe practicarse en todos los pacientes; el resto de los estudios están indicados en internados. El tratamiento inicial es empírico y debe iniciarse precozmente usando antibióticos activos frente a los gérmenes blanco, evitando el uso inapropiado que induce el desarrollo de resistencias. El tratamiento no debe prolongarse innecesariamente. Hidratación, nutrición, oxígeno y el manejo de las complicaciones complementan al tratamiento antibiótico. La prevención se basa en la profilaxis antinfluenza y antineumocóccica, evitar la aspiración y medidas generales.

PDF

http://www.scielo.org.ar/pdf/medba/v63n4/v63n4a09.pdf

March 22, 2017 at 3:46 pm

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