Ulaştırma Eski Bakanı Veysel Atasoy MRSA kurbanı oldu ...
C.diff cases may be twice as high as tests miss infection ...
C.diff cases may be twice as high as tests miss infection
The number of cases of the hospital bug C.diff could be twice as high as previously thought as current tests used by the NHS are failing to pick up the infection, experts have claimed.
By Rebecca Smith, Medical Editor Published: 7:15AM GMT 04 Nov 2009
There are around 3,000 cases of Clostridium difficile reported in hospitals in England each month but the true figure could be much higher as the current testing methods miss between 20 per cent and 80 per cent of cases, according to microbiologists.
Prof Gary French, consultant microbiologist at Kings College London and Guy's and St Thomas' Foundation Trust, has carried out research showing that the current test only correctly identifies around 38 per cent of cases of C.diff. Other trials have suggested about half of cases are found.
The research, which is due to be published in the Journal of Hospital Infection, suggests new methods using two-stages, one to screen for the presence of C.diff and if positive another more sophisticated test to establish if the bug is producing the toxins which cause symptoms or is lying dormant.
C.diff is a bacterium that can be found naturally in the gut of some people without causing problems but in others it can produce toxins which trigger diarrhoea. Vulnerable elderly patients and those who have been on antibiotics in hospital are more susceptible and the disease can prove fatal in some cases.
The results from current tests used in NHS hospitals can take several days.
Prof David Persing, consulting professor of pathology at Standford University in California and chief medical officer of Cepheid, a company which produces pathology tests, said his research has shown that the tests only found about 50 per cent of positive C.diff cases.
"The data was quite surprising. The tests are not doing anywhere near as well as we thought. For some strains they are only picking up about 20 per cent of the infections that are there. The vasst majority of patients who are infrected with some of these strains are being missed and are not being put in isolation. There is no attempt to even treat the patient if the test comes back negative," he said.
He said for strain 106, which is common in Britain, the current test only detected around 20 per cent of cases but for the more virulent 027 strain the tests found 80 per cent of cases.
The new tests are more accurate and faster, he said, but they can be three time more expensive. However, by finding positive cases faster, NHS hospitals could cut their infection rates and reduce duplicate tests to save money in the long run.
Prof French also found that the current tests are 'inadequate' and called for new methods to be employed. But he added that patients with symptoms are isolated and treated accordingly without waiting for test results and they may continue to be treated even if the result is negative.
He said: "From our paper and other studies, we show that the present tests are not as reliable as they should be… I think that these tests are really not good enough. We need recommendations to move to a new system and this should be debated."
Prof French said that although new tests may find more cases it should not be taken as a rise in C.diff prevalence but would be the result of more accurate testing. He said the downward trend in C.diff cases shown by mandatory reporting of cases to the Health Protection Agency is probably still the case.
He said: "The hygiene improvements across the board, shown by the dramatic reduction in MRSA rates, means I am convincted taht the reduction in C.diff rates is a true phenomenon.
"If we go to a new test that is more sensitive we are bound to see an increase in reported cases. That will not be a result of poor practice but the result of better testing."
The latest C. Difficile figures show that there were 6,855 cases reported in patients aged two years and over during the April to June 2009. This is a drop of 37 per cent on the same period last year.
Dr Christine McCartney, Executive Director for the Health Protection Agency's Healthcare Associated Infection and Anti-Microbial Resistance Programme, said: “Studies have suggested that different tests have better efficacy rates depending on the strain of Clostridium difficile.
“The Agency works closely with the Department of Health to ensure all infection control guidelines take any new strains of health care associated infection into account to ensure health care settings have the most up to date evidence and research possible to help combat healthcare associated infections.”
Brian Duerden, Inspector of Microbiology and Infection Control at the Department of Health said: "Accurate test results are essential for good patient care. In March this year we issued advice on a two-stage testing approach and reminded trusts that patients should be isolated and treated as Clostridium difficile patients if they were symptomatic, even if they tested negative.
"We will be evaluating the results of this study, along with other studies currently underway, as part of a review into healthcare acquired infection testing. We will continue to work tirelessly to tackle these infections."
Testing methods will be discussed at a symposium at Guy's and St Thomas' Hospital.
New, more expensive tests should be brought in, but hospital managers would need reassurance that any apparent rise in cases found by the new methods should not be seen as poor patient care, they said.
Universal Screening Helps Prevent MRSA Hospital Infection Outbreaks: Presented at ICAAC ...
By Ed Susman SAN FRANCISCO -- September 15, 2009 -- Researchers said that hospital-acquired infections with methicillin-resistant Staphylococcus aureus (MRSA) can be largely prevented by identifying carriers of the organism when patients are admitted to the hospital and then initiating aggressive isolation procedures, even if patients are not experiencing disease symptoms but are colonised by the bacteria. Lance Peterson, MD, Microbiology and Infectious Diseases Research, NorthShore University HealthSystem, Chicago, Illinois, said if hospital staff is not aggressive in conducting isolation programs with persons carrying MRSA, the infection control program is doomed to fail. The aggressive program initiated at his hospitals in 2005 resulted in a 70% reduction in MRSA infections rates, and even though the costs associated with the program added to the hospital budget, the resulting savings in preventing infections was triple the cost, Dr. Peterson said here on September 12 at the 49th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC). The study at the 3 NorthShore system hospitals in Evanston, Illinois, revealed that about 7 of every 100 individuals who had MRSA colonisation developed a symptomatic infection. "The biggest risk factor for MRSA infection is to be colonised," he said. The 3 hospitals used real-time polymerase chain reaction testing to screen incoming patients for colonisation with MRSA. Upon presentation at the hospital, patients had their nostrils swabbed for pathogens. If MRSA was detected the patients were isolated and treated with mupirocin for 5 days. Staff treating these patients wore gowns and gloves for contact precautions, he said. Patients were also given 2 antiseptic baths. The polymerase chain reaction test is more expensive than traditional tests, and additional nursing care precautions also added costs to the program, Dr. Peterson said. "The bottom line for us is that if you want to have a successful MRSA reduction program," he said, "you have to have a very aggressive, very rapid, and broad MRSA screening program." Dr. Peterson and colleagues studied 37,179 consecutive patients who underwent MRSA-testing at admission. The prevalence of MRSA was 8.5%, but two-thirds of the individuals were not aware they were carriers of MRSA. "Successful control of any epidemic relies on detection of those harbouring the pathogen and limiting further spread," he said. "The approach to control of the MRSA pandemic is no different. Most persons harbouring MRSA do not exhibit signs of infection and thus to detect all spreaders some surveillance must be done." [Presentation title: Debate: Is Molecular Screening for MRSA Colonization Worth the Cost? Case in Favour. Abstract 408]
Tests to Rapidly Diagnose Sepsis Essential Diagnostic That Can Quickly Detect Infection ...
Source - ( Sep 15, 2009 )
Sepsis is a major healthcare problem. There are approximately 750,000 cases of sepsis each year in the U.S. And the number is growing.
Sepsis results from complex interactions between infecting microorganisms and host immune, inflammatory, and coagulation responses. Severe sepsis is defined as sepsis with organ dysfunction. Severe sepsis with hypotension, despite adequate fluid resuscitation, is septic shock. Septic shock and multiorgan dysfunction are the most common causes of death in sepsis patients. Mortality associated with severe sepsis remains unacceptably high—20 to 50%. When shock is present, mortality is even higher—40 to 60%.
Distinguishing patients with localized infections or a systemic inflammatory response (SIRS) from those with sepsis is challenging. SIRS is not specific to sepsis and can result from other conditions such as acute pancreatitis and immunodeficiencies. This makes a quick diagnosis, difficult.
Today, blood culture and culture techniques are the gold standard for detection of infection. Physicians order cultures as soon as two or more SIRS criteria are identified. The turnaround time for culture/blood culture is lengthy, ranging from 48 to 72 hours. As a result, antimicrobial therapy administration usually begins before culture results are available.
The choice of appropriate broad-spectrum antimicrobial therapy is tricky because of the rising prevalence of resistant pathogens. Today, this choice is left up to the physician’s intuition. Patients with severe sepsis or septic shock, however, have little margin for error in what therapy they receive. Consequently, there is a huge unmet need for fast turnaround tests that enable early administration of antimicrobial therapy/antibiotics by rapid identification of infection and facilitate choice of antimicrobial therapy through rapid identification and detection of causative pathogen.
Future sepsis diagnostic options include single-analyte immunoassays and molecular identification, for which opportunities exist at both the front and back ends.
Among all single-analyte biomarkers, detection of a protein biomarker called procalcitonin (PCT) in serum holds the most promise. Serum levels of PCT have been shown to increase in patients with an infection; high values will be seen in cases of severe sepsis and septic shock.
Widespread use, however, is lacking. This is partly due to the lack of clinical trials with proper negative controls that differentiate septic from sepsis-like patients. Another difficulty lies with the riskiness of using a cut-off threshold of PCT to rule-out sepsis. Scientia’s research indicates that the possibility of false negatives is daunting and subsequent denial of antibiotic could increase the probability of mortality.
Another potential application of PCT is in therapy monitoring. PCT kinetics can be used to assess the effectiveness of treatment. If PCT levels do not begin to decline in a patient after four days of antibiotic treatment, the physician should consider changing the antibiotic regimen.
B.R.A.H.M.S. owns the IP on PCT and offers the test today along with bioMerieux. Several other immunoassay providers, including Roche Diagnostics and Siemens, have licensed PCT from B.R.A.H.M.S. And are offering it or intend to offer it on their immunoassay platforms.
Molecular identification of sepsis-causing pathogens might prove extremely helpful for rapid identification of pathogens and major antimicrobial resistance determinants. Rapid detection of hard-to-grow pathogens and antibiotic-resistant pathogens such as MRSA and VRE can significantly improve clinical outcome, enabling a narrowing of the spectrum of antibiotic coverage.
SeptiFast, a molecular sepsis test, has been launched by Roche Molecular Diagnostics in Europe. Adoption of this test has been disappointing as a result of its limited coverage of pathogens, automation issues, contamination problem, and cost.
Given the substantial barriers, many molecular diagnostic companies do not plan on taking up the daunting task of introducing a front-end molecular identification test and have resorted to the back end of identification of organisms directly in positive blood cultures instead.
The simplest of these back-end molecular identification tests is the PNA FISH (peptide nucleic acid fluorescent in situ hybridization) test. PNA FISH has the advantage of rapid hybridization kinetics and offers a sensitive way to identify S. Aureus, Enterococcus faecalis, or Candida albicans in positive blood culture samples. Identification is typically done within a few hours after a positive blood culture result is obtained. PNA FISH is available today and is offered by AdvanDx.
Another emerging methodology for identification of organisms in positive blood cultures is real-time PCR. Several companies such as Cepheid (with bioMerieux) are working toward developing such a test.
Sepsis is a complex and life-threatening disease. Significant improvements in the care, management, and treatment of sepsis patients have been realized recently. While early diagnosis remains a challenge and a rapid, sensitive, and specific diagnostic test is still lacking, these new approaches open up a whole new dimension in early diagnosis of sepsis and are likely to evolve into solutions for this major unmet need.
Taking Control of Tuberculosis Current diagnostic tools take weeks to provide ...
Source - ( Jul 16, 2009 )
Tuberculosis (TB) has taken a backseat over the last few decades as it has not received the funding appropriate to such a major health threat to the developing world. The World Health Organisation (WHO) published statistics last month showing that worldwide TB rates are stabilising at approximately 14 million cases, comprising one-third of the world’s population.
There are, however, a few countries where TB rates are increasing. The Health Protection Agency (HPA) has released statistics showing that the UK has seen a 2% increase (the only European country where TB is actually on the rise) and in African countries where HIV/TB co-infection is rife, TB deaths have quadrupled over the last 15 years. Clearly, tuberculosis is making a comeback - the disease is stronger now than ever before, and is rapidly becoming more drug-resistant, usually by gene mutations. In fact, much of the antibiotic resistance observed among TB strains is multi-drug resistance (MDR), showing resistance toward at least two first-line drugs. TB is second only to HIV as the world’s deadliest infectious disease, claiming a life every 20 seconds.
One of the key obstacles in controlling TB infection is the lack of fast and accurate diagnostic methods, particularly in areas of the world with the greatest disease burden. This article will examine those current diagnostics and reveal details of a new test that is set to revolutionise the way that TB is diagnosed and, therefore, controlled throughout the world.
Over the last year, the World Health Organisation has expressed concern that they may not be able to reach the targets for TB control as defined in the UN’s Millennium Development Goals (MDG’s). Those targets for 2015 included minimum requirements for cases detected and treated and required falling rates of TB incidence. Additionally, as defined in 2006 by the Stop TB Partnership, a global consortium of public health, non-government organisations, World Bank, pharmaceutical and other corporate stakeholders, governments, and academic institutions, prevalence and mortality rates should be decreased to one-half of the 1990 rates. This would essentially mean that 50 million people would receive treatment and 14 million lives would be saved.
As we know, early detection and proper treatment are essential to combat TB. UN Secretary-General, Ban Ki-Moon, argued that although “the epidemic is continuing its decline, the [global] rate of decline is far too slow, Unless we accelerate action, the numbers of those falling ill will continue to grow.” A 2008 report stated that “the detection rate increased only marginally to 61%, short of the 65% benchmark for 2006 contained in the Stop TB Partnership Global Plan and the ultimate target of 70%.”
One-third of TB cases come from Sub-Saharan Africa and Southeast Asia, where the main attributable factors are widespread poverty and a lack of adequate public healthcare.
People who have TB, or live in poverty, can often become mired in a vicious circle of continuous proliferation of both. TB most commonly attacks people in their working years crippling their ability to earn a living. Additionally, the costs associated with healthcare for TB can put families of sufferers under tremendous financial strain. This has a particularly significant impact on children who often become malnourished and have to leave school to take care of their family. In some cases, these children ultimately become orphans.
In turn, people living in poverty who cannot afford or access healthcare often share living space with many people, some of whom are already infected with TB. Spread of infection becomes much more likely in such settings.
There is a strong connection between HIV and TB. A third of all HIV/AIDS sufferers are co-infected with TB. The WHO Global TB Report stated that approximately 1.37 million HIV/AIDS sufferers were diagnosed with TB in 2008 - indeed TB is the leading cause of death amongst HIV sufferers. Shockingly, new data show that 25% of all TB deaths are HIV-related, double the amount previously thought.
Optimal TB management requires rapid detection, treatment, and prevention - but current technologies are outdated and impractical. The most commonly used methods have not changed in more than 125 years. According to the WHO, “only 2% of multi-drug resistant TB (MDR-TB) cases worldwide are being diagnosed and treated appropriately.”
The current testing method begins with spreading the patient’s sputum on a glass slide, treating the material with a special stain, and observing the slide under a microscope to detect the stained bacteria. The stain does not wash off the bacteria on the slide even when an acid solution is used, hence the organisms are called acid-fast bacilli (AFB). But this method, as practiced in high-burden parts of the world, fails to detect half of all active cases; a failure rate that is even higher in those co-infected with HIV. Tests that are more accurate exact a price, both monetarily and in the prolonged length of time it takes to achieve accurate detection of the TB bacteria by cultivating them in the laboratory. Due to the slow growth rate of the TB organism (the bacterium has a doubling time of 24 hours), growing the organism in culture can take weeks before results are available. It then takes even longer to determine if there is drug resistance, because the positive culture requires a second cultivation in the presence and absence of antibiotics in order to determine which antimicrobial agents are effective in inhibiting its growth. Employing all these procedures currently required to diagnose drug-resistant TB means that results may not be available for months.
Unfortunately for many patients in the developing world, this amounts to a post-mortem diagnosis, particularly as they are often co-infected with both TB and HIV - a rapidly fatal combination. Additionally, because diagnosis takes so long, these patients are sent back into the community, rather than isolated and treated appropriately, allowing for further transmission of the organism within the community in the local area.
In most of the developed world, isolation of patients with TB is implemented to prevent transmission to surrounding family and communities. However, even in the UK there are currently no guidelines advocating isolation during the time that the laboratory testing is being conducted, making a rapid diagnosis even more necessary.
Until now, if a clinician were to request a quicker TB diagnostic method than culture, accuracy would suffer. Sputum smear testing alone can theoretically produce results within a day. However 30% or more of patients whose sputum is smear-negative ultimately reveal positive cultures in follow-up tests, proving this diagnostic method to be highly insensitive and dangerously inaccurate. Missed diagnoses via smear testing are estimated to contribute to as much as 20% of newly transmitted TB infections. And in an unexpected twist of fate, patients with HIV/TB co-infection are actually more likely to be smear-negative but to progress rapidly to a fatal outcome.
As World TB Day arrived at the end of last month, Ki-Moon called for faster action to combat TB on a global scale. He highlighted the need for infection prevention, early detection, and worldwide availability of treatment, whilst calling for more effort to combat MDR-TB, XDR-TB (extensively drug-resistant TB), and the TB/HIV co-epidemic.
With this in mind, he called for organisations to come together and develop diagnostic solutions that will prevent the spread of the disease. Specifically, the WHO has called for faster and more accurate diagnostics based on the detection of specific DNA patterns in a gene called rpoB, found in all TB bacteria, that is considered to be a surrogate marker for MDR-TB.
In line with these announcements, a number of organisations have collaborated to develop a new diagnostic test for TB. The new test detects TB in less than two hours, is highly accurate, and has recently become available in Europe. The test is run on Cepheid’s GeneXpert System, a leading molecular testing platform, and was developed jointly by Cepheid, the Foundation for Innovative New Diagnostics (FIND), the University of Medicine and Dentistry of New Jersey (UMDNJ), and the US-run National Institute of Allergy and Infectious Diseases (NIAID).
Not only is the advanced technology able to detect the TB organism directly from sputum, it can also simultaneously detect rifampicin resistant strains of the infection via the presence of mutations in the rpoB gene, which is generally used as a surrogate marker for multi-drug resistance. And the test boasts unprecedented levels of sensitivity for detection of both smear-positive and smear-negative TB cases. Especially for HIV co-infected patients, the latter feature could be a life-saver.
This new test is one of the most important diagnostic developments to have occurred in many years. It is the most technologically advanced test for TB ever developed, yet it is simple enough to perform in all corners of the world, including resource-limited settings in which it is most needed.
When an individual is suspected of having a TB infection, the first step is often a chest X-ray. If the chest X-ray is suspicious, the patient is asked to cough and produce a sputum specimen, which is mixed with a solution that kills the TB organisms and placed into a small plastic GeneXpert cartridge. The GeneXpert System carries out steps that would have, until recently, required a dedicated laboratory facility and highly trained molecular diagnostic specialists. Within the cartridge, specimen processing and reagent mixing involving dozens of micro-pipetting steps are used to carry out nested real-time polymerase chain reaction (PCR), a method to multiply DNA in a test tube dramatically faster than occurs naturally in cultures. This reaction amplifies a DNA signature sequence that is specific to TB complex bacteria. DNA amplification and detection occur simultaneously within about 90 minutes. Because the test procedure is so simple, it is possible to run a STAT test on demand for patients with X-ray findings suspicious for TB, thus maximising the medical value of the test. At this time, all other PCR-based tests require multiple hands-on processing steps that necessitate performing the tests in batches.
Building on an ingenious protocol developed by Dr David Alland, M.D. And his colleagues at UMDNJ, the team engineered a protocol inside the GeneXpert cartridge that detects the presence of 5 different mutations in the core of the rpoB gene, now proven to detect virtually all rifampicin resistant strains of TB. Because rifampicin resistance is almost always present when there is resistance to other drugs, this result can be used to predict MDR-TB. Still more important is that the presence of rifampicin resistance predicts failure of first-line therapy, guiding the clinician to the most effective choice of second-line treatment and potentially avoiding costly treatment failures that lead to progressive disease and continued spread to others.
Tuberculosis is not an infection that is going to vanish overnight and, contrary to popular belief, it is not a disease from the 19th century that we no longer need to worry about, although it should be. It is a tragedy that we have not yet managed to eradicate this devastating infection from the world, both in developing countries and in our own supposedly developed country. Its close links with poverty and the HIV virus make it a much more widespread and serious issue in Africa and Southeast Asia, but it is also a concern in the UK and Europe. With over 8,000 new cases of TB reported every year in the UK, we are seeing the number of cases increase, bucking the global trend. It is my sincere hope that this new diagnostic test, which will soon be available throughout the world, will mark the tipping point when we finally start to win the battle against TB.
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