March 03, 2018
Monitoring systems would allow animal antibiotic consumption levels to guide policies. In a paper in Plos Medicine, CDDEP Director, Ramanan Laxminarayan, and coauthors in Thailand proposed the establishment of surveillance systems in low- and middle-income countries that would optimize the use of antibiotics and help combat antimicrobial resistance in the animal production sector. The authors argue that policies are needed to preserve key antibiotics for therapeutic use and to slow the spread of resistant organisms, as rising demand for meat and fish has resulted in increasingly intensive production that includes the use of antimicrobial growth promoters. [PLoS Medicine]
Overprescribing in primary care in England. In a special supplement in Clinical Infectious Disease, research by Public Health England (PHE) found that at least 20% of all antibiotics prescribed in primary care in England are inappropriate. The total is likely higher, because while the majority of antibiotic prescriptions written were for respiratory or urinary tract infections, almost a third of all prescriptions had no clinical reason for the prescription documented. In addition, the research found that, similar to CDDEP’s work in United States, there was great variation in prescribing among practices across the country. However, variation between practices could not be explained by differences in the patients seen, suggesting that differences in rates of inappropriate prescribing may be driving variation among practices. [Clinical Infectious Diseases]
High antimicrobial resistance in zoonotic bacteria in Europe. A report by the European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC) analyzing antimicrobial resistance in zoonotic bacteria in humans and animals found in addition to continued high levels of resistance, several emerging threats to human health. The report details significant differences in antimicrobial resistance between countries and found that between 2008 and 2016 countries with national control programs of AMR in food producing animals were more likely to register decreasing trends in resistance compared to countries with no control programs. Worryingly, two countries found carbapenem resistant E. coli isolates from chickens (Cyprus, Romania) and one country reported linezolid resistant MRSA isolates in pigs (Belgium). [European Food Safety Authority]
Targeting control interventions for tuberculosis in high-incidence settings. Population-wide trials of active case detection for TB have been disappointing. However, these trials have been largely untargeted. Researchers examined whether a targeted approach would be more effective. Specifically, they examined whether a strategy that uses annual testing of patients who have previously completed TB treatment would be effective in a high-incidence setting. Using a mathematical model, the researchers found that this type of target approach could significantly reduce the burden of TB over a ten-year period. [The Lancet Global Health]
Increasing burden of debt among Tuberculosis patients in India. With almost 2 million cases of TB reported by the WHO in 2016, India has the highest number of TB cases in the world. Though the government provides free medicine to patients, high prevalence of multi-drug resistant TB in India reduces treatment options and worsens prognosis. For many patients already afflicted by poverty, drug therapy can mean crippling debt as side effects of treatment lead to lost income and travel and food expenditures accumulate. In private care settings, the burden is even greater with patients spending more than double their income (i.e., borrowing money or seeking loans) to support treatment. While TB patients await fulfillment of government promises to bolster financial and nutritional support, adherence to medication will remain a growing challenge for public health, as acute and chronic financial strain poses a disincentive for continued treatment. [Reuters]
Triclosan induces multidrug resistance through mutations. Triclosan, a non-antibiotic, antimicrobial (NAAM) agent commonly found in toothpaste and detergents, is widely detected in the environment. Based on evidence that triclosan may be linked to antibiotic resistance, the U.S. Food and Drug Administration (FDA) imposed a ban on its use in antimicrobial soaps. However, global action has been hampered by a lack of conclusive evidence of the link between triclosan and antibiotic resistance. A recent study by researchers from the University of Queensland found that wild-type E. coli exposure to triclosan produced multiple antibiotic resistance in E. coli through highly heritable genetic mutations. These findings suggest that triclosan, at environmentally relevant concentrations, can induce multi-drug resistance. [bioRxiv]
New CRISPR inventions reveal potential use as a biosensor. Advances in CRISPR, a powerful gene editing technology, has produced three new inventions that attempt to harness the power of CRISPR to turn cells into biosensors. The first uses CRISPR to record events that happen to a cell by writing them into the cell’s DNA. One potential application of this system is system that could sense environmental pollutants in remote locations. The second used CRISPR to glow when it identifies HPV, a virus which causes cervical cancer, in a test tube, raising hopes of an inexpensive means of screening blood in outbreaks in resource-poor settings. The third uses a paper strip to detect specific sequences of DNA and RNA to determine whether a blood sample contains infectious disease such as Zika or influenza. [Science, Science, Science, Statnews]
New potential antimalarial drug targets discovered. Malaria kills more than 400,000 people each year, many of them because the parasites are resistant to common antimalarial drugs. Researchers from the Francis Crick Institute recently identified two key proteins that allow malaria parasites to maintain infections in humans. Parasites invade human cells and replicate. They then need to burst out of the cell to infect more cells. Researchers used genetic knockout experiments to demonstrate that two key proteins are necessary for the parasite to successfully escape the cell. The hope is that drugs could be designed to target these proteins. [Nature Microbiology]
De-worming can exacerbate the risk from malaria. Researchers from Princeton University, examining how malaria and bloodsucking hookworms compete for red blood cells in infected patients, found that deworming patients led to increases in malaria parasite densities. The researchers examined more than 4,000 patients over a 2-year period that were part of a deworming study. They were interested in how malaria and helminths interacted in patients and whether competition for RBCs reduced the density of both infections or whether cross-immune functions were responsible. What they found was that in patients that were dewormed the density of parasites increased, suggesting strongly that competition for resources (RBCs) is the main way malaria and helminths interact in patients. These results suggest that rapid co-infection detection should be a component of deworming interventions to mitigate the potential for increased malaria burden. [Ecology Letters]
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