Anthrax-like Bacillus cereus strain eyed for Select Agent bioterror list

The US Centers for Disease Control and Prevention (CDC), part of the Department of Health and Human Services (HHS) yesterday proposed adding Bacillus cereus biovar anthracis to the list of HHS select agents and toxins as a Tier 1 Select Agent, the most concerning as a possible bioterrorism agent. The close relative of B anthracis, the bacterium that causes anthrax, also causes an anthrax-type disease.

"We are taking this action to regulate this agent that is similar to B. anthracis to prevent its misuse, which could cause a biological threat to public health and/or national security," the CDC said in a Federal Register notice. The interim final rule will become effective Oct 14 after a comment period.

B cereus biovar anthracis was originally isolated about 10 years ago from gorillas and chimpanzees that exhibited anthrax-like symptoms in Cameroon and Cote d'Ivoire. Since then both those countries have reported human cases. "We are currently aware that geographic distribution of B. cereus Biovar anthracis is limited to some African countries, one registered entity in the United States, and one facility in Germany," the CDC said in the notice.

The HHS/CDC Intragovernmental Select Agents and Toxins Technical Advisory Committee (ISATTAC) first took up the topic of classifying the bacterium as a Tier 1 agent in December 2015. The ISATTAC considered the pathogen's pathogenicity, communicability, ease of dissemination, environmental stability, ease of lab production, impact on the healthcare system, and other factors in reaching its decision.

In reaching its decision, officials said, "HHS/CDC is not proposing to regulate other strains of B. cereus that have B. anthracis toxin genes as the data available do not suggest those strains pose a severe threat to public health."
Sep 14 Federal Register notice


Trial: New shingles vaccine highly effective in adults over 70

An experimental vaccine against herpes zoster (shingles) was highly effective against the disease and postherpetic neuralgia in adults 70 and older, maintaining protection for at least 4 years, according to phase 3 findings published yesterday in the New England Journal of Medicine.

The study of the subunit adjuvanted candidate vaccine HZ/su, funded by its maker, GlaxoSmithKline (GSK), was conducted in 18 countries. It featured a trial design identical to one in adults age 50 and older for which researchers reported similarly promising results in April 2015.

To test the vaccine specifically in the age-group most at risk for shingles, researchers enrolled 13,900 participants; half received two doses of the vaccine 2 months apart, and half received two doses of placebo. Participants were followed for at least 30 months after the second dose. Almost all participants (94.4%) received both doses.

During the follow-up period, herpes zoster was reported in 23 HZ/su recipients compared with 223 of the placebo recipients. Vaccine efficacy was 89.8% (95% confidence interval [CI] 84.2% to 93.7%). And it was only slightly lower in participants ages 80 or older—89.1%. The results were similar to those for older subjects in the earlier study.

Factoring in data from the older age-group in the earlier study allowed the investigators to gauge the efficacy against postherpetic neuralgia, which was 88.8% (95% CI, 68.7% to 97.1%).

Injection-site and systemic reactions within a week of vaccination were higher in the HZ/su group, but serious adverse events and deaths were similar in the vaccine and placebo groups.

Emmanuel Hanon, PhD, GSK's senior vice president of vaccine research, said in a company press release yesterday, "This is the first time that such high efficacy has been demonstrated in a vaccine candidate for older people and it is remarkable, as we know that these people frequently have an age-related weakening of their immune system," he said. "If approved, this candidate vaccine could be an important tool for the prevention of shingles and the pain associated with it, which would significantly impact the health and quality of life of so many people."

GSK said it expects to start submitting applications later this year for regulatory approval for use of the vaccine in preventing shingles in people age 50 and older.
Sep 14 N Engl J Med abstract
Sep 14 GSK press release


Salmonella outbreaks tied to backyard poultry on the rise

A report yesterday in Emerging Infectious Diseases shows that live poultry–associated salmonellosis (LPAS) outbreaks are on the rise as more Americans keep backyard chickens.

Researchers identified 53 LPAS outbreaks (defined as two or more illnesses) from 1990 to 2014. There were 2,630 cases of Salmonella illness, resulting in 387 hospitalizations, and 5 deaths. Children were most at risk for illness; the median patient age was 9, and 42% of patients were 10 years of age or younger. Chick and duckling exposure was reported by 85% and 38% of case-patients, respectively.

Though Salmonella illness is commonly foodborne, it can also be transmitted through touching poultry. The researchers found certain high-risk behaviors were linked to cases, including keeping poultry indoors (46% of patients) and kissing poultry (13% of patients.)

The authors conclude with a reminder that, "Poultry can appear healthy and still shed Salmonella bacteria intermittently for extended periods of time. … In addition, intermittent shedding could partially explain why recent outbreaks have been of a longer duration, some lasting up to 12 months."
Sep 14 Emerg Infect Dis study


Ghana, Cameroon report H5N1 in poultry

Ghana and Cameroon reported new outbreaks of highly pathogenic H5N1 avian flu today, according to the World Organization for Animal Health (OIE).

Almost 500 poultry in Ghana were destroyed after H5N1 was found in two separate backyard outbreaks. Both outbreaks occurred in the Greater Accra region. The first began on Sep 1 and involved 32 fatal cases of H5N1 in cockerels, guinea fowls and local fowls. The other outbreak involved the death of 119 layers who lived in deep litter on Sep 8. All surviving birds were culled to prevent disease spread.

In Cameroon, a large commercial farm lost 34,400 poultry after 2,628 birds were infected with avian flu and died in an outbreak that began on Aug 29. The birds included commercial layers and a population of breeders.

In other news, France announced today it will lift the avian flu restriction zone for the southwest part of the country that experienced outbreaks over the past year, according to a story by Reuters. By Sep 1, France had recorded 81 outbreaks of highly pathogenic avian flu.
Sep 15 OIE Ghana report
Sep 15 OIE Cameroon report
Sep 15 Reuters story


Malaria net uses two insecticides to fight mosquitoes

A new study in Science Translational Medicine describes a novel mosquito net that can sterilize female mosquitoes. The Olyset Duo net uses a mixture of insecticides to combat increasing resistance to pyrethroid-treated nets widely used in sub-Saharan Africa.

The unwashed Olyset Duo, which uses a mixture of permethrin and pyriproxyfen insecticides, was 100% effective in killing mosquitoes; effectiveness dropped to 70% after 5 to 20 washes. Compared with the standard pyrethroid-only Olyset Net, the Duo sterilized more mosquitoes. The original Olyset net was introduced to parts of Africa 20 years ago, and has lost effectiveness as resistance to pyrethroid has risen in those regions.

"Insecticide treated nets are the most important tool we have in the fight against malaria, and it's encouraging to see new technology which in the future could continue to prevent malaria transmission in vulnerable communities," said Professor Mark Rowland of the London School of Hygiene and Tropical Medicine (LSHTM), in an LSHTM news release. Researchers at the school developed the new net in partnership with Sumitomo Chemical Co. of Japan.
Sep 15 Sci Transl Med study
Sep 15 LSHTM press release

Antimicrobial Resistance Scan for Sep 15, 2016

News brief

NDM-1 detected in 27 Vibrio fluvialis isolates in India

Although MCR-1 has often garnered drug-resistance headlines of late, an earlier gene that also confers antimicrobial resistance, NDM-1 (New Delhi metallo-beta-lactamase) has not gone away, as evidenced by a study yesterday in Emerging Infectious Diseases. Researchers reported the gene in 27 Vibrio fluvialis isolates in Kolkata, India.

NDM-1 was first discovered in 2009, with the first US cases reported in 2010. It has been reported most commonly in India and Pakistan. MCR-1 was first detailed in a report late last year and renders pathogens resistant to the last-line antibiotic colistin. Most NDM-1 strains are susceptible to colistin but resistant to most commonly used antibiotics.

In the new study, Indian researchers were screening samples from hospitalized patients who had diarrhea when they identified the 27 NDM-1 V fluvialis isolates, which were resistant to all antimicrobials tested except doxycyline. The genes flanking the NDM-1 genes were identical to those identified in a comparison NDM-1 Escherichia coli bacterium isolated previously.

The scientists were also able to transfer the NDM-1-containing plasmid to other pathogens such as E coli, but those pathogens exhibited a slightly less extensive antimicrobial resistance profile.

The authors concluded, "The pathogenicity of V. fluvialis to humans and its ubiquitous presence in the environment call for constant monitoring of this species for emerging antimicrobial drug resistance."
Sep 14 Emerg Infect Dis report


Study says WHO guidelines might underestimate cure in MDR-TB patients

A new study suggests that the way the World Health Organization (WHO) defines "cure" for patients with multidrug-resistant tuberculosis (MDR-TB) may underestimate how many people recover from the disease.

The study, published in the New England Journal of Medicine, evaluated treatment outcomes for 380 European MDR-TB patients according to WHO definitions and compared them with simplified definitions of treatment outcomes. Under the WHO guidelines, cure was defined as treatment completion with at least three negative cultures after the intensive phase of therapy in the absence of treatment failure. Under the simplified definition, cure was defined as a negative culture status 6 months after treatment initiation, no positive culture thereafter, and no relapse within 1 year after treatment completion.

The study found that relapse-free cure was achieved in 61% of patient with MDR-TB, 52% of patients with pre-extensively drug-resistant (XDR) TB, and 39% of patients with XDR-TB. Under the WHO definition, 31%, 27%, and 24% of patients, respectively, were considered cured.

"In conclusion, current WHO definitions may underestimate cure in patients with MDR tuberculosis," the study authors wrote. "These definitions could be simplified while incorporating the assessment of post-treatment relapse."
Sep 15 N Engl J Med correspondence

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