A recent study conducted by researchers at the Emory University School of Medicine and Grady Memorial Hospital, has reported a substantial rise in the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections. Previously, Staphylococcus infections resistant to antibiotics were hospital associated, however, the study now reveals the concerning trend of such infections becoming widespread within the community as well.
S. aureus usually resides in the nose of many people and occasionally leads to serious infection. The CDC reports that S. aureus is a leading cause of skin infections in the USA.
Henry M Blumberg, senior author of the study, and professor of medicine and program director of the Division of Infectious Diseases at Emory University School of Medicine and hospital epidemiologist at Grady Memorial Hospital, stated that, “We have seen an explosion of community-acquired MRSA infections among the urban patient populations served by the Grady Health System. CA-MRSA infections are no longer restricted to certain risk groups but appear to be widespread in the Atlanta community.”
Blumberg and other Emory and Grady authors noted that, “Empirical use of antibiotics active against CA-MRSA is warranted, especially for patients presenting with serious skin and soft-tissue infections.” This represents a major change in prescribing practices for community-onset skin and soft-tissue infections.
The results of this study have direct implications for the way that skin and soft-tissue infections are managed. Previously Blumberg notes that, “skin and soft-tissue infections occurring in the community were generally methicillin-susceptible S. aureus, and that is how antibiotic therapy was targeted.” At present it may be assumed that CA-S. aureus infections will not be resistant to antibiotics, such as methicillin, and as a result patients could be prescribed with ineffective antibiotics.
In response Blumberg suggests, “selection of empiric antibiotics should focus on covering MRSA,” and there ought to be a focus on definitive and prompt diagnosis to prevent the misuse of current antibiotics. Blumberg and colleagues will continue their research and aim to determine which the most effective agents to combat CA-MRSA are. Until then the CDC suggests implementation of the tried and tested antidote of soap and water, and good hygiene.
Immunization drive reduces measles deaths by almost half
The WHO and the United Nations Children’s Fund (UNICEF) have recently announced that global immunization drives have reduced measles deaths almost by half between 1999 and 2004.
Measles is one of the most highly contagious diseases known to man. Indeed, a safe, effective and inexpensive vaccine has been available since the 1960s to treat the disease, however, as a result of lack of widespread availability, many children still die from the disease, often from complications related to severe diarrhea and pneumonia. Many who survive are left with lifelong disabilities including blindness and brain damage.
“Measles remains a major killer of children in the developing world, but it doesn’t have to be,” UNICEF Executive Director Ann Veneman said. “Just two doses of an inexpensive, safe and available measles vaccine can prevent most, if not all, measles deaths.”
Between 2000 and 2004 further measles immunization initiatives were offered in 36 out of 45 developing countries; 215 million (93%) of the 232 million children resident in these 36 countries were vaccinated. Statistics show that in 1999 871,000 people died of measles while, following the immunization initiatives, in 2004 an estimated 454,000 died – a 48% reduction.
The most impressive reduction in mortality has been seen in sub-Saharan Africa, where the highest measles disease burden exists; current estimates show a reduction of 59%, from approximately 530,000 deaths in 1999 to approximately 216,000 deaths in 2004.
“This is an outstanding public health success story,” said Lee Jong-wook, WHO Director General. “If progress continues at this rate, the global goal to cut measles deaths by half will have been achieved on time.”
Immunization efforts, as well as efforts to improve treatment and surveillance, have been focused on 47 countries identified by the WHO and UNICEF as accounting for 98% of global measles deaths.
Although African countries have made great strides to reduce the burden of measles, progress in south Asia has not been quite so forthcoming. Efforts now should be directed towards ensuring immunization coverage reaches 90%.
The Measles Initiative, launched in 2001, has been the key player in progress to reduce measles deaths. With support from partners such as the Global Alliance for Vaccines and Immunization, the measles initiative has raised US$150 million. The Initiative now aims to expand its support to south Asian countries.
Researchers from Leeds fight the battle against infectious disease
Tuberculosis (TB), malaria and HIV are the worlds most life-threatening diseases resulting in the death of 6 million people annually. In an effort to address these issues researchers from Leeds are set to embark on a £5 million, 5-year project to ensure effective treatments promptly reach those in need.
“Our vision is to contribute at a global level to a better understanding of ways to combat communicable diseases,” said John Walley, codirector of the communicable disease program, COMDIS. Walley and codirector James Newell plan to work with research partners, national TB, AIDS and malaria programs, patients, doctors and policy makers across Asia and Africa to develop practical and affordable improvements or ‘interventions’, to save lives from these diseases. “An intervention can both cure patients and prevent the spread of disease,” said Walley.
“Take for example, improving the way people take their TB medication. If they take it properly, they’ll be cured and won’t pass it on to other people. The intervention could be better communication, better education or improving the way health systems pick up and care for people with health problems.”
A key aspect of the provision of effective healthcare is timely intervention; however, this is reliant on a well organized and integrated healthcare system, which simply does not exist in developing countries. “Although solutions are out there for disease control, the major problem is being able to use these in ways that are responsive to patient needs, cost effective and sustainable,” said Walley.
The program aims to explore and improve current methods of healthcare provision for the poor and vulnerable; this could involve anything from community-based TB care to theater to address issues such as stigma and discrimination.
“If we can demonstrate the effectiveness of new strategies in reducing health equalities in a cost-neutral way, they are more likely to be taken up by communicable disease programs,” said Newell. “Improving quality by addressing access, efficiency, equity and effectiveness can help programs achieve their goals without heavy investment. We believe that the relevance and timeliness of our evidence can dramatically alter the approach and results of reaching the poor.”
The new strategies are based on 10 years of public health program design and realization to ensure the methods are sustainable, affordable and acceptable.
“Our strength is the longstanding relationship and track record we have with in-country disease control programs,” said Newell. “Rather than lip service, national control programs are involved throughout.”
Preceding the COMDIS program the Nuffield researchers developed strong relationships in the field, in Pakistan, as a result of their international health and development TB research program. As a result, successful treatment rates have risen from 30% to an average of 82%. Similar programs have been put in place in China.
The aim of COMDIS is to project their approach to TB onto other diseases, across different countries, such as in the treatment of HIV in Uganda and Swaziland.
“The involvement of policy makers from the beginning is crucial for researchers to address key operational constraints, and for rapid knowledge dissemination.”
“At first sight there are plenty of solutions to healthcare problems in these countries but the challenge is finding ones that can really work under the difficult conditions seen in developing countries,” said Walley. “COMDIS will make sure that research makes a real difference to a huge number of people.”
Mosquitoes genetically engineered to be resistant to dengue fever virus
Researchers from the University of California, Colorado State University and from Virginia Polytechnic Institute and State University, USA, have genetically engineered a mosquito which has demonstrated resistance to the most prevalent type of dengue fever virus. The study could pave the way for the development of a vaccine or treatment to combat the disease which infects 50 million people each year.
Dengue fever is a flu-like viral disease transmitted by mosquitoes of the species Aedes aegypti. The symptoms include high fever, rash, severe headache, pain behind the eyes and muscle and joint pain. The illness can continue for up to 10 days, often taking up to 1 month to completely recover. Some cases of dengue fever can lead to dengue hemorrhagic fever which is fatal in approximately 5% of cases, mostly among children and young adults. The WHO estimates approximately 50 million cases of dengue infection occur each year, with approximately 20,000 fatalities.
The research team included Anthony James, a University of California Irvine vector biologist, who injected DNA into mosquito embryos to create the first stable transgenic mosquito resistant to type 2 dengue fever virus. The mosquitoes which survived also remained fertile, which is key to future strategies involving the replacement of mosquito populations with their genetically modified counterparts.
“These results are very exciting because they provide us a genetic tool we can use to control mosquito-borne diseases such as dengue fever,” James said. “We have been working for some time on the individual components of creating a genetically modified mosquito that would fend off dengue infection, but this is the first time we have brought all the pieces together to create a stable model that can also reproduce.”
The researchers were able to exploit a vulnerability of the dengue virus in order to result in mosquitoes resistant to infection. The virus becomes vulnerable when it replicates and its single strand of RNA briefly becomes double stranded. When left to its own devices the virus is only subjected to this self-destructive process once it had undergone replication. However, the researchers have now discovered a method to control and manipulate this process, in order to render the virus benign. Mosquitoes could then be inoculated with this benign form in order to confer resistance.
Descendents of the original mosquitoes were also found, to be mostly resistant when tested. Furthermore, it was possible for the researchers to locate the sections of engineering RNA in the mosquitoes, which demonstrates that the genetic alteration had been successful and relayed through the generations. When the genetic modification was reversed the mosquitoes became as susceptible to the virus as they had been previously.