Weekly Digest: Ebola vaccine offers 100 percent protection; U.S. antibiotic use in food animals continues to rise

29 Dec 2016
Author: Ellyse Stauffer

A weekly roundup of news on drug resistance and other topics in global health. 

Ebola vaccine offers 100 percent protection. rVSV-ZEBOV provided complete protection in a “ring vaccination” cluster randomized trial, including contacts and contacts-of-contacts of Ebola patients in Guinea and Sierra Leone, reported in The Lancet. The vaccine is a recombinant, replication-competent, vesicular stomatitis virus-based vaccine that expresses the glycoprotein of a Zaire Ebolavirus. The trial compared immediate vaccination of 2119 people in 52 clusters with 21-day delayed vaccination of 2041 individuals in 47 clusters in the Basse-Guinée region of Guinea, and in Tomkolili and Bombali in Sierra Leone. An unrandomized vaccinated group was added partway through the trial. From day 10 after vaccination, no cases of Ebola were detected in those vaccinated immediately versus 23 cases (in 11 different clusters) in the deferred group (plus unvaccinated contacts in the immediate group). While the vaccine has not yet been approved by any regulatory authority, an emergency stockpile of 300,000 doses has already been created in the event of another outbreak. [Lancet, New York Times]

For pediatric ear infections, shortened courses of antibiotics may lead to worse outcomes than standard-duration. Researchers conducted this study to find out if limiting the duration of antimicrobial treatment could provide effective treatment and reduce the risk of antimicrobial resistance among children with acute otitis media (middle ear infection). Researchers randomly assigned 520 infants with acute otitis media to receive amoxicillin-clavulanate for the standard 10-day course or for five days followed by 5 days of placebo. The five-day course resulted in a 17-percent higher risk of clinical failure (77 of 229 children) compared to those who received the standard duration (39 of 238 children). The shortened course also had no detectable effect on the emergence of antibiotic resistance.  [NEJM]

Antimicrobial use in food animals continues to rise, according to FDA report. The U.S. Food and Drug Administration released its annual report on antimicrobials sold or distributed for use in food-producing animals, based on 2015 surveillance data. Sales and distribution of all antimicrobials increased one percent between 2014 and 2015 (the lowest annual increase since 2009) and use of antimicrobials considered medically important in human medicine increased by two percent. Aminoglycoside sales rose 13 percent from 2014 through 2015 and cephalosporin sales rose by 61 percent. Medically important antibiotics accounted for 62 percent of all antibiotics sold for use in food-producing animals in 2015; approximately 70 percent of all medically important antibiotics in the United States are sold for use in animals. [FDA, CIDRAP]

Antimicrobial resistance agenda must include improved fungal diagnostics and antifungal stewardship. Experts comment in Emerging Infectious Diseases on the need to include improved fungal diagnostics and treatment in the antimicrobial resistance agenda. The authors highlight the lack of routine diagnostic testing for fungal diseases, which “exacerbates the problem of antimicrobial drug empiricism, both antibiotic and antifungal.” The authors cite inaccurate diagnosis of fungal sepsis and fungal asthma, which often results in inappropriate use of broad-spectrum antibiotics rather than appropriate antifungal drugs. The authors conclude, “The lack of availability and underuse of nonculture fungal diagnostics results in overprescribing, prescription of unduly long courses of antibacterial agents, and excess empirical use of antifungal agents and leaves many millions of patients with undiagnosed fungal infections.” [EID]

Access to Medicine Foundation plans to develop AMR Benchmark to track pharma response to drug resistance. The accountability tool, which will focus on the pharmaceutical industry’s response to antimicrobial resistance, will complement existing accountability initiatives developed by Pew Charitable Trusts to track antibiotics currently in development, Farm Animal Investment Risk & Return to measure farming practices related to antibiotic use, and CARA: The Conscience of Antimicrobial Resistance Accountability, developed by CDDEP. Methodology for the first Benchmark will be formulated in early 2017. [Access to Medicine Foundation]

In US, hospitals penalized for high rates of MRSA and C difficile. The U.S. federal government has cut Medicare payments to 769 hospitals with high rates of patient injuries, counting for the first time the spread of antibiotic-resistant infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile. The 25 percent of hospitals with the highest rates of hospital-acquired conditions nationally will lose one percent of all Medicare payments for one year, estimated by the Association of American Medical Colleges to exceed one million dollars for many larger hospitals and in total, approach $430 million. [Kaiser Health News, CIDRAP]

Does the human microbiome influence risk for obesity? Anthony Komaroff of Harvard Medical School makes the case for potential effects of human microbiota in the development of obesity and Type 2 diabetes in JAMA. Plausibility is established because, as Komaroff puts it, “Genes drive biochemistry, the human microbiome contains exponentially more genes than there are human genes, and those microbial genes produce molecules that affect human physiology.” A number of animal experiments are consistent with the hypothesis. The mix of bacterial species, which differs between obese and normal weight individuals, is a potential explanatory factor, but much is still to be learned to clarify the existence and details of an association. [JAMA]