Because of slow growth of mycobacteria, use of rapid tests to identify them is strongly recommended; rapid tests are widely used as an advanced diagnostic tool in clinical laboratories (1,2). These tests are particularly useful for diagnosing extrapulmonary mycobacterioses and identifying unusual mycobacteria as etiologic agents (3). Commercial probes are frequently used for rapid and specific identification of mycobacteria, especially Mycobacterium tuberculosis complex. However, cross-reactivity of DNA probes between mycobacterial species could result in incorrect diagnosis and treatment of patients (4,5). Misidentification could be a problem if a newly described species, such as M. kumamotonense (6), were an etiologic agent of a disease.
In July 2006, we obtained a fine-needle, puncture aspiration biopsy specimen from a cervical lymph node of a 30-year-old man at Doce de Octubre Hospital (Madrid, Spain). The patient was a recent immigrant from Paraguay and was HIV positive (C2 stage of infection). A biopsy specimen from a cervical lymph node showed necrotizing granulomatous lymphadenopathy. A computed tomographic scan showed cervico-thoraco-abdominal, multiple cervical, supraclavicular, axillar, paratracheal, and mediastinal lymphadenopathies. The patient had a CD4 cell count of 219 cells/mm3 and an HIV viral load of 197,181 copies/mL.
The aspiration sample was positive for acid-fast bacilli by fluorescent staining. The clinical isolate (designated 1369) obtained from the aspirate sample was grown in liquid media (MGIT Diagnostic Kit; Becton Dickinson Diagnostics, Sparks, MD, USA) and identified as M. tuberculosis complex by using the AccuProbe System (bioMérieux, Marcy l'Etoile, France).
A diagnosis of lymphoid tuberculosis was made, and the patient was treated with isoniazid, rifampin, ethambutol, and pyrazinamide. After 1 month, rifampin was withdrawn because of a cutaneous exanthem. Three months later, the clinical status of the patient had improved, fever had disappeared, and sizes of cervical and axillary lymph nodes had decreased. Treatment with tenofovir, emtricitabine, and lopinavir/ritonavir was started. Two weeks later, an immune reconstitution syndrome and adenopathies developed, but these resolved in 1 month.
Five months after treatment was started, susceptibility testing in a reference laboratory showed that isolate 1369 was M. kumamotonense. The isolate showed 100% identity with the 16S rRNA gene sequence of M. kumamotonense (GenBank accession no. AB239925). Results of PCR restriction analysis of heat shock protein 65 gene (7) (http://app.chuv.ch/prasite/index.html) were consistent with those for M. kumamotonense. The isolate was susceptible to ethambutol, rifampin, cycloserine, and ethionamide and resistant to isoniazid, streptomycin, pyrazinamide, and kanamycin.
http://www.cdc.gov/eid/content/16/7/1178.htm
Showing posts with label misdiagnosis. Show all posts
Showing posts with label misdiagnosis. Show all posts
Monday, 9 August 2010
Friday, 18 June 2010
MALARIA: demand for microscopes
THE lack of microscopes in government-aided health centres in Bushenyi district has hindered the fight against malaria, the district medical officer, Dr. Celestine Barigye, has said. Barigye said because of the shortage of microscopes, medical officers cannot diagnose diseases thoroughly. Barigye said when the patients go to health centres complaining of fever, the medical workers just prescribe malaria medicine even when they (patients) are not suffering from the disease. Barigye was speaking at a one-day malaria control workshop for stakeholders at Katungu Mothers’ Union Conference Centre in Bushenyi town. The workshop was organised by the West Ankole Diocese. Barigye called upon the Government to intensify the distribution of insecticide-treated mosquito nets, especially to the rural people who cannot afford them. He said to have a malaria-free country, there was need to sensitise the population about the disease. The diocese’s planning and development officer, Richard Mwesigwa, said the Church of Uganda had partnered with the district to distribute mosquito nets to vulnerable people.
http://www.newvision.co.ug/D/8/18/722638
http://www.newvision.co.ug/D/8/18/722638
Thursday, 29 April 2010
MALARIA: Problems in practical therapy
Despite the widespread availability of effective new drugs and diagnostic tools, malaria still poses a risk to half the world’s population, and each year about a million people die of the disease, heard a seminar held at the London School of Hygiene and Tropical Medicine to mark world malaria day on 25 April.
The United Nations has called for universal provision of insecticide treated bed nets and prompt treatment for all people at risk of malaria by the end of this year, to achieve the goal of near zero deaths by 2015.
Yet major problems remain. Issues such as misdiagnosis and overprescription of treatments, counterfeit drugs, problems in supply and delivery, and emerging resistance to drugs "all hamper effective treatment." A lack of awareness among donors and the public of some these basic problems "threaten the success of global malaria control efforts."
Brian Greenwood, professor of clinical tropical medicine at the London School of Hygiene and Tropical Medicine, pointed out that treating malaria 40 years ago was much easier, as virtually every child in rural Africa had parasites in their blood, and treatments were cheap and effective. Nowadays prevalence was down to 5-10%, making it necessary to pick out those who needed treatment. Doctors had also failed to appreciate the danger of reliance on monotherapy, which had led to widespread resistance to chloroquine, making it essential to find effective new combination treatments.
Chris Whitty, head of research at the UK Department for International Development, said that these days "almost every death from malaria is an avoidable tragedy." The roll-out of effective new artemisinin based combination therapies meant that the disease was easily treatable, yet for various complex reasons people aren’t getting the drugs they need. Many people fail to seek care, many receive treatment in the informal sector, and many don’t get effective antimalarials.
Most people with malaria are poor, he said, and unable to afford the indirect costs of formal health care, meaning that many people still bought cheaper, less effective drugs from the private sector. Existing drugs are cheap but ineffective, while effective drugs are not cheap.
David Bell of the World Health Organization said that the development of rapid diagnostic tests showed that only about a quarter of cases of fever were actually malaria and that more than 50% of those treated for symptoms of malaria did not actually have the disease.
In Africa over half of cases of malaria were diagnosed on symptoms, not tests. Mr Bell emphasised that without parasite based diagnosis most recipients of artemisinin based combination therapies would not have malaria, which meant not just a waste of scarce resources but also that non-malarial febrile illness went undiagnosed and untreated. The roll-out of new diagnostics has left a problem of how to treat non-malarial fevers. It was essential to build effective programmes, not just to fund procurement, he said.
Shunmay Yeung, senior lecturer in health economics and policy at the London School of Hygiene and Tropical Medicine, described the alarming development of resistance to artemisinin in Cambodia. She said that the resistance was only to artemisinin, not to combination therapies that include artemisinin derivatives, which underlined the need for combination rather than monotherapies.
The problem of counterfeit and substandard drugs was discussed by Paul Newton, reader in tropical medicine at Oxford University, who emphasised the need to differentiate between the two as they had different causes and solutions. Although substandard drugs were an issue of quality assurance, counterfeits were the work of criminal gangs which required a concerted effort by Interpol. Counterfeit drugs were already "an under-appreciated public health disaster" in Asia and now posed a tremendous threat in Africa, he said.
http://www.bmj.com/cgi/content/full/340/apr27_3/c2295?
The United Nations has called for universal provision of insecticide treated bed nets and prompt treatment for all people at risk of malaria by the end of this year, to achieve the goal of near zero deaths by 2015.
Yet major problems remain. Issues such as misdiagnosis and overprescription of treatments, counterfeit drugs, problems in supply and delivery, and emerging resistance to drugs "all hamper effective treatment." A lack of awareness among donors and the public of some these basic problems "threaten the success of global malaria control efforts."
Brian Greenwood, professor of clinical tropical medicine at the London School of Hygiene and Tropical Medicine, pointed out that treating malaria 40 years ago was much easier, as virtually every child in rural Africa had parasites in their blood, and treatments were cheap and effective. Nowadays prevalence was down to 5-10%, making it necessary to pick out those who needed treatment. Doctors had also failed to appreciate the danger of reliance on monotherapy, which had led to widespread resistance to chloroquine, making it essential to find effective new combination treatments.
Chris Whitty, head of research at the UK Department for International Development, said that these days "almost every death from malaria is an avoidable tragedy." The roll-out of effective new artemisinin based combination therapies meant that the disease was easily treatable, yet for various complex reasons people aren’t getting the drugs they need. Many people fail to seek care, many receive treatment in the informal sector, and many don’t get effective antimalarials.
Most people with malaria are poor, he said, and unable to afford the indirect costs of formal health care, meaning that many people still bought cheaper, less effective drugs from the private sector. Existing drugs are cheap but ineffective, while effective drugs are not cheap.
David Bell of the World Health Organization said that the development of rapid diagnostic tests showed that only about a quarter of cases of fever were actually malaria and that more than 50% of those treated for symptoms of malaria did not actually have the disease.
In Africa over half of cases of malaria were diagnosed on symptoms, not tests. Mr Bell emphasised that without parasite based diagnosis most recipients of artemisinin based combination therapies would not have malaria, which meant not just a waste of scarce resources but also that non-malarial febrile illness went undiagnosed and untreated. The roll-out of new diagnostics has left a problem of how to treat non-malarial fevers. It was essential to build effective programmes, not just to fund procurement, he said.
Shunmay Yeung, senior lecturer in health economics and policy at the London School of Hygiene and Tropical Medicine, described the alarming development of resistance to artemisinin in Cambodia. She said that the resistance was only to artemisinin, not to combination therapies that include artemisinin derivatives, which underlined the need for combination rather than monotherapies.
The problem of counterfeit and substandard drugs was discussed by Paul Newton, reader in tropical medicine at Oxford University, who emphasised the need to differentiate between the two as they had different causes and solutions. Although substandard drugs were an issue of quality assurance, counterfeits were the work of criminal gangs which required a concerted effort by Interpol. Counterfeit drugs were already "an under-appreciated public health disaster" in Asia and now posed a tremendous threat in Africa, he said.
http://www.bmj.com/cgi/content/full/340/apr27_3/c2295?
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