News Scan for May 11, 2017

News brief

CDC issues final cholera vaccine recommendations for adult travelers

The US Centers for Disease Control and Prevention (CDC) today finalized its cholera vaccine recommendation for adults traveling to disease outbreak areas, based on June 2016 advice from its Advisory Committee on Immunization Practices (ACIP).

ACIP's recommendation last summer came in the wake of the Food and Drug Administration's approval of Vaxchora, making it the first cholera vaccine available to US travelers. The live vaccine is given as a single dose for adults 18 through 64 and targets Vibrio cholerae serogroup O1.

The CDC recommends the vaccine only for adults going to areas of active cholera transmission, not for routine travel. Examples include people going to affected areas to visit family or for health providers or cholera outbreak responders. The full recommendation, which also covers administration with other medication or vaccines, as well as contraindications and precautions, appears today in Morbidity and Mortality Weekly Report (MMWR).
May 12 MMWR report
May 11 CDC press release

Number of pregnant US women with hepatitis C doubled in recent years

The number of pregnant women in states reporting hepatitis C (HCV) infections almost doubled from 2009 to 2014, according to a report today in Morbidity and Mortality Weekly Report (MMWR).

During the 6-year period studied, the prevalence of maternal HCV infection among reporting states increased 89%, from 1.8 to 3.4 per 1,000 live births. The increases are most drastically seen in white, rural, poor regions of the country, particularly in areas of Tennessee and West Virginia the researchers, from Tennessee, reported. Smoking and infection with hepatitis B increased the risk of maternal HCV infection, 4.5-fold and 17-fold, respectively.

"The increase in maternal HCV infection coincides with the rising heroin and prescription opioid epidemics occurring in the United States that have also disproportionately affected rural and white populations," the authors write. "There has also been a recent surge in opioid use among pregnant women."
May 12 MMWR study

Analysis highlights human threats from high-path H7N9 in China

Highly pathogenic H7N9 avian influenza, detected in people for the first time in China in 2013, have a slightly increased binding preference for human airway receptors compared with the low-pathogenic form, a research team from China reported today in Eurosurveillance.

The scientists also found that highly pathogenic H7N9 containing the R292K substitution was resistant to multiple antivirals, requiring urgent further assessment. In January, Taiwan reported a resistance mutation in an imported case involving a patient infected with highly pathogenic H7N9.

For their study, the researchers compared high-path H7N9 genetic sequences from patients infected earlier this year in Guangdong province with low-pathogenic H7N9 and highly pathogenic H5N6.

Compared with low-path H7N9, the highly pathogenic form showed slightly increased binding preference for the types of receptors found in human upper and lower airways. The researchers said high-path virus's persistent preference for both avian and human receptors may result in their circulation in poultry and possible transmission among people.

The team confirmed that the high-path viruses showed little or no response to antibodies against the low-path H7N9 vaccine strain. The World Health Organization has already recommended a new candidate vaccine strain for the new form of the virus.

In their analysis of antiviral resistance, the investigators found that high-path H7N9 that contained the R292K substitution in the neuraminidase protein showed resistance to oseltamivir (Tamiflu), zanamivir (Relenza), and peramivir. They said the virus had the ability to acquire the substitution as early as 2 days after the administration of the antiviral drugs.

They concluded that highly pathogenic H7N9 doesn't pose an enhanced risk solely to poultry; it also has implications for human health surveillance and control strategies. The authors also said their findings are a reminder of the crucial role of antiviral surveillance monitoring as a key component of pandemic preparedness.
May 11 Eurosurveill report

Bangladesh reports pair of H5N1 outbreaks; more H5N8 in Germany

Bangladesh reported two recent highly pathogenic H5N1 avian flu outbreaks, and Germany reported one more H5N8 outbreak in poultry, according to the latest notifications from the World Organization for Animal Health (OIE).

The Bangldeshi events both occurred in Dhaka, the country's capital. One of the outbreaks began on Apr 13 in backyard birds, and the other event began on Apr 20 at a farm. Between the two locations, the virus killed 66 of 160 birds, and the survivors were culled to control the spread of the virus. Bangladesh's last H5N1 occurred in January at a commercial farm, also in Dhaka. H5N1 is endemic in the country's poultry.

Germany's H5N8 outbreak began on May 8 in backyard chickens in North Rhine-Westphalia state. The virus killed 10 of 13 susceptible birds, and the rest were destroyed as part of the control measures.
May 11 OIE report on H5N1 in Bangladesh
May 10 OIE report on H5N8 in Germany

WHO warns of cholera, other health threats to Somalia, Yemen

In a pair of announcements today, the World Health Organization (WHO) warned of drought and disease threats to Somalia and a resurgence of cholera in Yemen.

In Somalia, an ongoing funding shortage is threatening the response to drought that is pushing the country into a famine and increasing the risk of infectious diseases, the WHO said in a statement today. It said drought has led to a lack of clean water, which is fueling the country's biggest cholera outbreak in 5 years. So far this year more than 36,000 cases and 690 deaths have been reported. Floods expected with the upcoming rainy season could push the illness total past 50,000 by the end of June, the group warned.

Somalia is also in the midst of a measles outbreak, with 6,500 cases reported so far in 2017, 71% of them in children younger than 5.

The WHO says it has only 23% of the $103 million it needs for the overall response in Somalia and that it has only 10% of the $25 million it needs for an organizational response. It commended the United Kingdom for hosting an international conference to tackle Somalia's challenges, and it called for more support from the international community.

Meanwhile, the WHO said in a separate statement that it and its partners are responding to a surge in cholera in several parts of Yemen that since Apr 27 has resulted in 2,752 suspected cases, 51 of them fatal. The agency said it has already distributed supplies and treatments and is building 10 new treatment centers in affected areas.

Yemen has been battling cholera since October 2016 amid a health system that has been weakened by 2 years of conflict. Warmer weather and rains have also played roles in the spread of the disease.
May 11 WHO statement on Somalia
May 11 WHO statement on Yemen

Stewardship / Resistance Scan for May 11, 2017

News brief

Novel antifungal drug shows early promise against Candida auris

A novel antifungal drug has shown in vitro activity against the emerging fungal pathogen Candida auris, researchers report in Antimicrobial Agents and Chemotherapy.

In lab experiments, investigators from the Mycotic Diseases Branch of the Centers for Disease Control and Prevention (CDC) and biotechnology company SCYNEXIS evaluated the in vitro susceptibility of SCY-078, a triterpine glucan synthase inhibitor that has shown activity against other Candida species, against a collection of 100 isolates of C auris. The collection of isolates came from all over the world, represented the four known clades of C auris, and included isolates known to have elevated minimum inhibitory concentrations against echinocandins—a class of glucan synthase inhibitors used to treat Candida and other fungal infections.

The investigators report that SCY-078 showed potent activity against all the clades of C auris, with little variation in activity, and also retained its activity against the isolates that were resistant to echinocandins.

C auris was originally discovered in 2009 in Japan and since then has emerged as a global health threat due to its growing resistance to all three major classes of antifungals used in Candida infections. The CDC estimates the mortality from drug-resistant yeast, which can cause bloodstream, wound, and ear infections, at approximately 60%. More than 60 C auris cases have been reported in the United States.

"These initial results are extremely encouraging and highlight the potential of SCY-078 to address this growing public health crisis," David Angulo, MD, study co-author and chief medical officer at SCYNEXIS, said in a company press release. "We look forward to continuing to accelerate the development of this promising therapy."
May 8 Antimicrob Agents Chemother abstract
May 11 SCYNEXIS press release

Researchers uncover prehistoric origins of enterococci

A study today in the journal Cell suggests that enterococci, the bacterial organisms that live in the human and animal gut and have become a significant source of drug-resistant hospital infections, emerged more than 400 million years ago, and that their exposure to environmental stresses enabled them to build up defenses against antibiotics.

In the study, researchers from Harvard Medical School, Massachusetts Eye and Ear, and the Broad Institute selected 24 enterococcal species representing all major phylogenetic branches and sequenced their genomes in an attempt to understand how these organisms adapted to the modern hospital environment. Then, using molecular clock estimation, along with analysis of their environmental distribution, phenotypic diversity, and concordance with host fossil records, they were able to determine that these organisms emerged around 425 million years ago, right around the same time as land animals. And as new species of animals emerged, so did new species of enterococci.

As animals crawled onto land, they carried enterococci with them in their intestines, and when the microbes were excreted, they were exposed to cycles of isolation, starvation, and desiccation until they re-entered the food chain. Over millions of years of exposure to these environmental stresses, the researchers argue, enterococci developed hardened cell walls and acquired genes that made them resistant to drying out—the same traits that today make them resistant to many antibiotics and hospital disinfectants.

As a result, the authors of the study write, "The emergence of enterococci as leading hospital pathogens appears to have been foreordained by events of at least 425 million years ago."

The authors say discovering that the environment in which microbes live leads to new properties could enable scientists to predict how microbes will adapt to the products intended to control their spread, and inform efforts to develop new solutions to drug resistance.
May 11 Cell abstract
May 11 Massachusetts Eye and Ear Infirmary news release

CDC notes rise of pneumococcal strain not susceptible to penicillin

Experts from the US Centers for Disease Control and Prevention yesterday noted the concerning recent rise of a pneumococcal serotype not susceptible to penicillin that they say should be considered for inclusion in any vaccine that would replace the current 13-strain pneumococcal conjugate vaccine (PCV13).

Writing in Emerging Infectious Diseases, the investigators detailed their analysis of 199 nonvaccine serotype 35B pneumococcal strains isolated from patients in 2015 and 2016. The incidence of this strain increased from 1.2 to 1.3 cases per million population in 1998 and 1999 to 2.1 to 3.7 cases per million in the post–pneumococcal 7-valent conjugate vaccine (PCV7) years (2001-2009). It then jumped again post-PCV13, to 3.3 to 4.8 cases per million. PCV13 was introduced in 2010.

In addition, "penicillin-nonsusceptible" strains of 35B increased in the post-PCV7 years and increased even more post-PCV13. This shift was propelled primarily by a 35B lineage called ST558. This 35B/ST558 strain then combined genes with a serotype 9V/ST156 strain in 2015 and 2016, spawning new 35B/ST156 progeny in at least six states.

The authors conclude, "Spread of 35B/ST156 is of concern in view of past global predominance of pathogenic ST156 vaccine serotype strains. Protection against serotype 35B should be considered in next-generation pneumococcal vaccines."
May 10 Emerg Infect Dis report