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Search Results: 1 - 10 of 3446 matches for " Ruth McNerney "
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Variable Number of Tandem Repeats (VNTR) and its Application in Bacterial Epidemiology
Rashid Ramazanzadeh,Ruth McNerney
Pakistan Journal of Biological Sciences , 2007,
Abstract: Molecular epidemiology is the using of molecular techniques to study bacterial distribution in human populations. Recently molecular epidemiologist benefit from several techniques such as Variable Number Tandem Repeat (VNTR) typing method to typing bacterial strains. Variable Number Tandem Repeat (VNTR) typing is a tool for genotyping and provides data in a simple and numeric format based on the number of repetitive sequences. VNTR for first time identified in M. tuberculosis as Mycobacterial Interspersed Repeat Units (MIRUs). General terms of VNTR have now been reported in Bacillus anthracis, Legionella pneumophila, Pseudomonas aeruginosa, Salmonella enterica and Escherichia coli O157.
Multidrug-resistant tuberculosis
Ellen M Zager, Ruth McNerney
BMC Infectious Diseases , 2008, DOI: 10.1186/1471-2334-8-10
Abstract: Whereas the prevalence of tuberculosis is presented as the proportion of individuals within a defined population having disease, the prevalence of drug resistant tuberculosis is usually presented as the proportion of tuberculosis cases exhibiting resistance to anti-tuberculosis drugs. Global surveillance activities have identified countries in Eastern Europe, the former Soviet Union and regions of China as having a high proportion of MDR-TB cases and international commentary has focused primarily on the urgent need to improve control in these settings. Other regions, such as sub-Saharan Africa have been observed as having a low proportion of drug resistant cases. However, if one considers the incidence of new tuberculosis cases with drug resistant disease in terms of the population then countries of sub-Saharan Africa have amongst the highest rates of transmitted MDR-TB in the world. We propose that inclusion of population based statistics in global surveillance data is necessary to better inform debate on the control of drug resistant tuberculosis.Re-appraisal of global MDR-TB data to include population based statistics suggests that the problem of drug resistant tuberculosis in sub-Saharan Africa is more critical than previously perceived.Control of tuberculosis (TB) remains one of the most serious challenges to global health. In 2005 there were an estimated 8.8 million new cases and 1.6 million deaths [1]. TB is predominantly a disease of poverty with over 80% of cases occurring in Asia or Africa. Although the greatest numbers of patients live in the highly populous countries of Asia the highest incidence of disease is found in the WHO region of Africa. Nine countries in sub-Saharan Africa have recently reported estimated annual incidences in excess of 600 cases per 100,000 [2], a burden of disease not witnessed since before the advent of chemotherapy. The continued rise of TB in this region may be largely attributed the AIDS pandemic combined with weak healthcar
Propagation of Respiratory Aerosols by the Vuvuzela
Ka-Man Lai,Christian Bottomley,Ruth McNerney
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020086
Abstract: Vuvuzelas, the plastic blowing horns used by sports fans, recently achieved international recognition during the FIFA World Cup soccer tournament in South Africa. We hypothesised that vuvuzelas might facilitate the generation and dissemination of respiratory aerosols. To investigate the quantity and size of aerosols emitted when the instrument is played, eight healthy volunteers were asked to blow a vuvuzela. For each individual the concentration of particles in expelled air was measured using a six channel laser particle counter and the duration of blowing and velocity of air leaving the vuvuzela were recorded. To allow comparison with other activities undertaken at sports events each individual was also asked to shout and the measurements were repeated while using a paper cone to confine the exhaled air. Triplicate measurements were taken for each individual. The mean peak particle counts were 658×103 per litre for the vuvuzela and 3.7×103 per litre for shouting, representing a mean log10 difference of 2.20 (95% CI: 2.03,2.36; p<0.001). The majority (>97%) of particles captured from either the vuvuzela or shouting were between 0.5 and 5 microns in diameter. Mean peak airflows recorded for the vuvuzela and shouting were 6.1 and 1.8 litres per second respectively. We conclude that plastic blowing horns (vuvuzelas) have the capacity to propel extremely large numbers of aerosols into the atmosphere of a size able to penetrate the lower lung. Some respiratory pathogens are spread via contaminated aerosols emitted by infected persons. Further investigation is required to assess the potential of the vuvuzela to contribute to the transmission of aerosol borne diseases. We recommend, as a precautionary measure, that people with respiratory infections should be advised not to blow their vuvuzela in enclosed spaces and where there is a risk of infecting others.
Evaluation of phage assay for rapid phenotypic detection of rifampicin resistance in Mycobacterium tuberculosis
Sergio Yzquierdo, Dihadenys Lemus, Miguel Echemendia, Ernesto Montoro, Ruth McNerney, Anandi Martin, Juan Palomino
Annals of Clinical Microbiology and Antimicrobials , 2006, DOI: 10.1186/1476-0711-5-11
Abstract: Phage D29 assay was performed on 102 M. tuberculosis strains to detect rifampicin resistance. The results were compared with the proportion method (gold standard) to evaluate the sensitivity and specificity of Phage assay.Phage assay results were available in 2 days whereas Proportion Methods results were obtain in 42 days. A total of 44 strains were detected as rifampicin resistant by both methods. However, one strains deemed resistant by Proportion Methods was susceptible by Phage assay. The sensitivity and specificity of Phage assay were 97.8 % and 100% respectively.Phage assay provides rapid and reliable results for susceptibility testing; it's easy to perform, requires no specialized equipment and is applicable to drug susceptibility testing in low income countries where tuberculosis is a major public health problem.Tuberculosis (TB) remains a major cause of morbidity and mortality worldwide. It is estimated that about one-third of the world's population is infected with Mycobacterium tuberculosis, more than eight million new cases of active TB occur annually and the estimated global annual mortality from this disease is close to two million people [1]. Multidrug-resistant tuberculosis (MDR-TB), caused by strains resistant to at least isoniazid (INH) and rifampicin (RMP), is considered an emergent disease as well as the consequence of inadequate treatment [2]. WHO has estimated that approximately 460.000 MDR-TB cases occur each year [3]. Estimated prevalence of MDR-TB ranges from 0% in some western countries to 14.2% in Kazakhstan and Israel, high prevalence has also been observed in the Russian Federation (Tomsk Oblast, 13.7%); Uzbekistan (Karakalpakstan, 13.2%), Estonia (12.2%), China (Liaoning Province, 10.4% and Henan Province, 7.8%), Lithuania (9.4%), Latvia (9.3%), and Ecuador (6.6%) [4].Currently available techniques for susceptibility testing are culture based, and include the proportion method (PM), resistance ratio and absolute concentration method. C
Field test of a novel detection device for Mycobacterium tuberculosis antigen in cough
Ruth McNerney, Beyene A Wondafrash, Kebede Amena, Ato Tesfaye, Elaine M McCash, Nicol J Murray
BMC Infectious Diseases , 2010, DOI: 10.1186/1471-2334-10-161
Abstract: The TB Breathalyzer device (Rapid Biosensor Systems Ltd) was field tested in the outpatient clinic of Adama Hospital, Ethiopia. Adults seeking diagnosis for respiratory complaints were tested. Following nebulization with 0.9% saline patients were asked to cough into a disposable collection device where cough aerosols were deposited. Devices were then inserted into a portable instrument to assess whether antigen was present in the sample. Demographic and clinical data were recorded and all patients were subjected to chest radiogram and examination of sputum by Ziehl-Nielsen microscopy. In the absence of culture treatment decisions were based on smear microscopy, chest x-ray and clinical assessment. Breathalyzer testing was undertaken by a separate physician to triage and diagnostic assessment.Sixty individuals were each subjected to a breathalyzer test. The procedure was well tolerated and for each patient the testing was completed in less than 10 min. Positive breath test results were recorded for 29 (48%) patients. Of 31 patients with a diagnosis of tuberculosis 23 (74%; 95% CI 55-87) were found positive for antigen in their breath and 20 (64%; 95% CI 45-80) were smear positive for acid fast bacilli in their sputum. Six patients provided apparent false positive breathalyzer results that did not correlate with a diagnosis of tuberculosis.We propose that the breathalyzer device described warrants further investigation as a tool for studying exhalation of M. tuberculosis. The portability, simplicity of use and speed of the test device suggest it may also find use as a tool to aid early identification of infectious cases. We recommend studies be undertaken to determine the diagnostic sensitivity and specificity of the device when compared to microbiological and clinical indicators of tuberculosis disease.With an estimated annual incidence of over nine million cases tuberculosis (TB) is believed to be responsible for more adult deaths each year than any other single inf
Poderes y Agencia: el resto es literatura / Proxy and Agency: the Rest is Literature
Katheen McNerney
Tejuelo : Didáctica de la Lengua y la Literatura , 2011,
Abstract: Resumen: De entre la gran multitud de emigrantes catalano-parlantes que llegó a la Cuba colonial, un cierto número de mujeres llegó a La Habana en busca de sus esposos, aquellos con los que se habían casado “por poderes” (poders) justo antes de realizar el largo viaje. La obra de Carmen Riera Cap al cel obert narra la historia de las hermanas Fortesa, enviadas desde Mallorca. A Isabel la eligió su padre para casarla con un primo rico y se envió a María para acompa arla. Solamente María sobrevive el terrible viaje, que tiene lugar durante la última fase del control espa ol sobre Cuba. Una vez en Cuba y recuperada de los avatares del viaje, María considera la vida monástica, pero en vez de ello, en su primera decisión real, acepta la oferta de matrimonio de Josep Fortalesa.El sistema de poderes continuó aun tras la independencia de Cuba del control de Espa a en 1898 y esta forma de matrimonio conforma el tema de L’herència de Cuba de Margarida Aritzeta, en cuya portada se describe como “absolutament verídica”. Eugènia se casa con Basilio, un vecino de su peque o pueblo aragonés cuando él, por medio de una carta y billete a la isla, manda que la traigan una vez instalado él allí después del viaje de 1925. Las dos novelas forman, de manera conjunta y a grandes rasgos, unos cien a os de historia cubana, desde finales del siglo diecinueve hasta finales del siglo veinte, poniendo de relieve la lucha de mujeres que a menudo parecen arrastradas como hojas secas en un huracán, como diría Gertrudis Gómez de Avellaneda.
Changes in Mycobacterium tuberculosis Genotype Families Over 20 Years in a Population-Based Study in Northern Malawi
Judith R. Glynn,Saad Alghamdi,Kim Mallard,Ruth McNerney,Richard Ndlovu,Lumbani Munthali,Rein M. Houben,Paul E. M. Fine,Neil French,Amelia C. Crampin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0012259
Abstract: Despite increasing interest in possible differences in virulence and transmissibility between different genotypes of M. tuberculosis, very little is known about how genotypes within a population change over decades, or about relationships to HIV infection.
Tuberculosis in Sudan: a study of Mycobacterium tuberculosis strain genotype and susceptibility to anti-tuberculosis drugs
Ghada S Sharaf Eldin, Imad Fadl-Elmula, Mohammed S Ali, Ahmed B Ali, Abdel Latif GA Salih, Kim Mallard, Christian Bottomley, Ruth McNerney
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-219
Abstract: In this study Mycobacterium tuberculosis isolates from 235 patients attending three treatment centers in Sudan were screened for susceptibility to isoniazid, rifampicin, ethambutol and streptomycin by the proportion method on Lowenstein Jensen media. 232 isolates were also genotyped by spoligotyping. Demographic details of patients were recorded using a structured questionnaire. Statistical analyses were conducted to examine the associations between drug resistance with risk ratios computed for a set of risk factors (gender, age, case status - new or relapse, geographic origin of the patient, spoligotype, number of people per room, marital status and type of housing).Multi drug-resistant tuberculosis (MDR-TB), being resistance to at least rifampicin and isoniazid, was found in 5% (95% CI: 2,8) of new cases and 24% (95% CI: 14,34) of previously treated patients. Drug resistance was associated with previous treatment with risk ratios of 3.51 (95% CI: 2.69-4.60; p < 0.001) for resistance to any drug and 5.23 (95% CI: 2.30-11.90; p < 0.001) for MDR-TB. Resistance was also associated with the geographic region of origin of the patient, being most frequently observed in patients from the Northern region and least in the Eastern region with risk ratios of 7.43 (95%CI:3.42,16.18; p: < 0.001) and 14.09 (95%CI:1.80,110.53; p:0.026) for resistance to any drug and MDR-TB. The major genotype observed was of the Central Asia spoligotype family (CAS1_Delhi), representing 49% of the 232 isolates examined.We conclude that emergence of drug resistant tuberculosis has the potential to be a serious public health problem in Sudan and that strengthened tuberculosis control and improved monitoring of therapy is needed. Further surveillance is required to fully ascertain the extent of the problem.The Republic of Sudan is the largest country on the African continent covering 2.5 million km2 with a current estimated population of approximately 45 million, 42% of whom are believed to be under
The analysis of para-cresol production and tolerance in Clostridium difficile 027 and 012 strains
Lisa F Dawson, Elizabeth H Donahue, Stephen T Cartman, Richard H Barton, Jake Bundy, Ruth McNerney, Nigel P Minton, Brendan W Wren
BMC Microbiology , 2011, DOI: 10.1186/1471-2180-11-86
Abstract: We show that the PCR-ribotype 027 strain R20291 quantitatively produced more p-cresol in-vitro and was significantly more tolerant to p-cresol than the sequenced strain 630 (PCR-ribotype 012). Tyrosine conversion to p-HPA was only observed under certain conditions. We constructed gene inactivation mutants in the hpdBCA operon in strains R20291 and 630Δerm which curtails their ability to produce p-cresol, confirming the role of these genes in p-cresol production. The mutants were equally able to tolerate p-cresol compared to the respective parent strains, suggesting that tolerance to p-cresol is not linked to its production.C. difficile converts tyrosine to p-cresol, utilising the hpdBCA operon in C. difficile strains 630 and R20291. The hypervirulent strain R20291 exhibits increased production of and tolerance to p-cresol, which may be a contributory factor to the virulence of this strain and other hypervirulent PCR-ribotype 027 strains.Clostridium difficile is a spore forming Gram-positive anaerobe and is the leading cause of hospital-acquired diarrhoea worldwide [1,2]. The hospital environment and patients undergoing antibiotic treatment provide a discrete ecosystem where C. difficile persists and selected virulent clones thrive. The recent upsurge in the number of C. difficile infection (CDI) cases has been linked to the rapid emergence of highly virulent and epidemic strains, known as PCR-ribotype 027. In the UK prior to 2005, 027 strains were rarely reported, but they now cause >33% of the 50,000 cases of CDI reported annually [3]. Several studies have revealed that patients infected with PCR-ribotype 027 strains have more severe diarrhoea, higher mortality and higher level of recurrence [4-8]. This is exemplified by the strain R20291, a prototypical PCR-ribotype 027 strain responsible for the infection of over 160 patients at the Stoke Mandeville hospital, UK in 2004/2005 [9].CDI characteristically occurs after treatment with broad-spectrum antibiotics. It is
Detection of Mycobacterium tuberculosis in Sputum by Gas Chromatography-Mass Spectrometry of Methyl Mycocerosates Released by Thermochemolysis
Denise M. O'Sullivan, Simona C. Nicoara, Reggie Mutetwa, Stanley Mungofa, Oona Y-C. Lee, David E. Minnikin, Max W. Bardwell, Elizabeth L. Corbett, Ruth McNerney, Geraint H. Morgan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032836
Abstract: Tuberculosis requires rapid diagnosis to prevent further transmission and allow prompt administration of treatment. Current methods for diagnosing pulmonary tuberculosis lack sensitivity are expensive or are extremely slow. The identification of lipids using gas chromatography- electron impact mass spectrometry (GC-EI/MS) could provide an alternative solution. We have studied mycocerosic acid components of the phthiocerol dimycocerosate (PDIM) family of lipids using thermochemolysis GC-EI/MS. To facilitate use of the technology in a routine diagnostic laboratory a simple extraction procedure was employed where PDIMs were extracted from sputum using petroleum ether, a solvent of low polarity. We also investigated a method using methanolic tetramethylammonium hydroxide, which facilitates direct transesterification of acidic components to methyl esters in the inlet of the GC-MS system. This eliminates conventional chemical manipulations allowing rapid and convenient analysis of samples. When applied to an initial set of 40 sputum samples, interpretable results were obtained for 35 samples with a sensitivity relative to culture of 94% (95%CI: 69.2,100) and a specificity of 100% (95%CI: 78.1,100). However, blinded testing of a larger set of 395 sputum samples found the assay to have a sensitivity of 61.3% (95%CI: 54.9,67.3) and a specificity of 70.6% (95%CI: 62.3,77.8) when compared to culture. Using the results obtained we developed an improved set of classification criteria, which when applied in a blinded re-analysis increased the sensitivity and specificity of the assay to 64.9% (95%CI: 58.6,70.8) and 76.2% (95%CI: 68.2,82.8) respectively. Highly variable levels of background signal were observed from individual sputum samples that inhibited interpretation of the data. The diagnostic potential of using thermochemolytic GC-EI/MS of PDIM biomarkers for diagnosis of tuberculosis in sputum has been established; however, further refinements in sample processing are required to enhance the sensitivity and robustness of the test.
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