News Scan for Aug 21, 2017

News brief

Almost 1,000 Salmonella cases now linked to backyard birds

A total of 961 cases of Salmonella illness have been linked to exposure to backyard poultry, according to an update today from the Centers for Disease Control and Prevention (CDC). The outbreaks have occurred in 48 states and resulted in 215 hospitalizations and 1 death.

The CDC and officials from multiple states are investigating 10 outbreaks involving 10 different Salmonella strain. Seventy-four percent of interviewed patients reporting they had contact with backyard birds in the week before falling ill.

Since the last update on Jul 13, 172 more people have been diagnosed as having Salmonella poisoning tied to exposure to backyard flocks of poultry, including chicks and ducklings from multiple hatcheries. Illnesses started from Jan 4 to Jul 31.

The CDC recommends that no children under the age of 5 handle live poultry without supervision. The CDC also recommended careful handwashing after handling backyard birds, their eggs, or anything in their environment.
Aug 21 CDC outbreak update

New polio cases reported in Afghanistan, Syria

The Global Polio Eradication Initiative (GPEI), in its weekly update today, reported 4 new cases of polio: a wild poliovirus type 1 (WPV1) case in Afghanistan and 3 new circulating vaccine-derived polio type 2 (cVDPV2) in Syria.

The vaccine-derived cases in Syria include two in Deir-ez-Zor and one in Homs governorates. Syria has now reported 33 cases of cVDPV2 this year, all but 2 in Deir-ez-Zor governorate. Onset of paralysis of these cases occurred between Mar 3 and Jul 10.

According to GPEI, an initial vaccination campaign with the oral polio vaccine 2 in Deir-ez-Zor was carried out from Jul 22 to 26, with independent monitoring showing coverage of 88.4%. A second round, which will include oral polio vaccine and injected vaccine, is planned for Aug 19 through Aug 23.

The new WPV1 case in Afghanistan raises its total in 2017 to 6. Afghanistan, Pakistan, and Nigeria remain the only countries in which wild poliovirus still circulates. In the most recent case, the patient was from Zabbul province and began having symptoms on Jul 10.
Aug 21 GPEI update

Study: Rebel areas bearing brunt of Yemen's cholera outbreak

The hardest-hit areas in Yemen's cholera outbreak are in rebel-controlled regions affected by Saudi-led airstrikes and blockades, researchers from Queen Mary University of London reported in an Aug 18 letter to The Lancet Global Health.

The team compared the World Health Organization's (WHO's) latest information about Yemen's outbreak with maps showing areas of government and rebel control, finding that the cholera outbreak disproportionately affects areas controlled by Houthi rebels. More specifically, they found that 77.7% of cases and 80.7% of deaths occurred in Houthi-controlled areas compared with government-held areas, which had 15.4% of cases and 10.4% of deaths.

The researchers said both sides of the conflict have been accused of disregarding citizens' wellbeing and breaching international humanitarian law, but they added that Yemen's government and the Saudi-led coalition that supports it command far greater resources and that the airstrikes have destroyed vital infrastructure such as hospitals and public water systems. The fighting has put displaced people into crowded conditions and blocked humanitarian aid.

The group also said countries such as the United States and United Kingdom, Saudi allies that have supplied Saudi Arabia's military, have helped create conditions fueling the spread of the disease.

Yemen's cholera outbreak, the world's largest, has now resulted in 537,322 suspected infections, 2,000 of them fatal, according to an Aug 20 update from the WHO.
Aug 18 Lancet Glob Health letter
Aug 18 Queen Mary University press release
Aug 20 WHO daily epidemiologic update

Stewardship / Resistance Scan for Aug 21, 2017

News brief

Dutch study find MCR-1 gene in a quarter of retail chicken meat samples

Dutch investigators have identified the colistin resistance gene MCR-1 in nearly 25% of samples of Dutch retail chicken meat, according to a new study in Antimicrobial Resistance and Infection Control.

For the study, the investigators bought 214 chicken meat samples from four supermarket chains throughout the Netherlands in 2015. They collected 53 or 54 samples from each chain.

Using polymerase chain reaction testing, the investigators detected the presence of the MCR-1 gene in 24.8% of the samples (53 of 214), then confirmed the presence of the gene in 34 of these 53 samples (64.2%) using a selective culture method. No MCR-2 genes were detected. Of the 34 MCR-1–positive isolates, 32 were Escherichia coli and 2 were Klebsiella pneumoniae. In addition to colistin, the 34 isolates showed high levels of resistance to ampicillin (100%), amoxicillin-clavulanic acid (89%), trimethoprim/sulfamethoxazole (69%), and ciprofloxacin (57%).

Multivariable regression analysis showed that chicken samples that were non-free-range (adjusted odds ratio [aOR], 3.0) and were purchased at supermarket chains C (aOR, 34.6) or D (aOR, 37.5) were more likely contain the MCR-1 gene. The large variation between supermarket chains could not be explained with the available information.

In previous studies of MCR-1 in food, researchers found the gene in 28% of Chinese poultry samples and in 19.5% of E coli isolates from South American chicken meat.

Although colistin and other polymixins are used at very low levels in the Netherlands and the MCR-1 gene has been found only sporadically in Dutch patients, the authors of the study say the findings warrant further studies on the underlying mechanisms of spread. "Moreover, continued monitoring of the potential reservoirs for this plasmid-mediated colistin resistance is of utmost importance," they write.
Aug 18 Antimicrob Resist Infect Control study

Survey finds varied antibiotic prescribing practices in pediatric residents

A survey of 85 pediatric residents at two US hospitals found considerable variation among antibiotic prescribing for pneumonia, sinusitis, and other conditions, with three-fourths having prescribed antibiotics for viral infections, according to a study last week in Hospital Pediatrics.

Among the residents surveyed at Children's National Medical Center in Washington, DC, and Nicklaus Children's Hospital in Miami, only 12% ranked an infectious disease specialist as one of their top three influential sources for antibiotic choice.

Seventy-five percent of respondents said they had prescribed antibiotics for patients they considered to have a viral infection. When asked to identify reasons for prescribing, 63% said they were following instructions from a more senior physician, 21% had concerns of a bacterial infection developing in the future, and 16% cited pressure from patients' parents.

Greater deviation from clinical guidelines was found for antibiotic treatment of sinusitis and community-acquired pneumonia compared with otitis media and streptococcal pharyngitis.

When asked about antibiograms, 54% said they sometimes used one, 25% had never referred to one, and 17% didn't know what an antibiogram was or didn't respond. Half of respondents didn't know how to access their hospital-specific antibiogram, which is a profile of antimicrobial susceptibility testing results for a single pathogen. Just 3% used the profiles very frequently.

The authors conclude, "Results illustrate the need for better promotion and integration of clinical guidelines with antibiograms when developing antibiotic education programs for residents in training. In addition, pediatric hospitalists should play an active role in the implementation of these programs."
Aug 16 Hosp Pediatr study

Patient trial for new antimalarial compound launches in Mali

Drugmaker Novartis and Medicines for Malaria Venture (MMV) today launched a patient trial in Mali for an antimalarial compound with the potential to treat drug-resistant strains of the parasite, according to a company press release.

The trial will test the efficacy of KAF156, which belongs to a novel class of antimalarial compounds called imidazolopiperazines, in combination with an improved formulation of the existing antimalarial lumefantrine. The phase 2b study will test multiple dosing combinations and dosing schedules of the drugs, including the feasibility of single-dose therapy in adults, adolescents, and children.

With resistance and reduced sensitivity to artemisinin and artemisinin-based combination therapies emerging in parts of Asia and more recently in Africa, next-generation antimalarials are urgently needed.

"To build on the gains made against malaria since the turn of the century, we need new medicines that are effective across all types of resistance patterns and geographies, and that are easy to administer, especially to children," David Reddy, PhD, chief executive officer of MMV, said in the release.

The first trial center is already operational in Mali and will be followed by trials in 16 additional centers in nine countries in Africa and Asia.

Novartis is developing KAF156 with scientific and financial support from MMV and the Bill and Melinda Gates Foundation.
Aug 21 Novartis press release

Non-carbapenems could be good option for bloodstream infections

European researchers report in Clinical Infectious Diseases that empiric treatment of bloodstream infections (BSIs) caused by extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-E) with drugs other than carbapenems is not associated with worse outcomes.

While carbapenems are generally considered to be the drug of choice for treating serious infections caused by ESBL-E, their use has substantially increased in recent years, and there is concern that the increase is contributing to the spread of carbapenem resistance. Some recent data have indicated that beta-lactam/beta-lactamase inhibitor combinations are an alternative, but there are few data on other antimicrobials. Alternative agents with potential efficacy could provide more treatment options.

As part of a larger multinational retrospective cohort study on BSIs caused by ESBL-E, researchers set out to assess the impact of empiric therapy with other active drugs (OADs) compared with carbapenem treatment. The main outcome was 30-day all-cause mortality. Secondary outcomes were clinical failure at day 14 and length of hospital stay after BSI. The hypothesis was that treatment with OADs would be associated with higher mortality and lower cure rates.

Overall, 335 patients with BSI due to ESBL-E were included in the study; 249 were treated empirically with a carbapenem and 86 with OADs. The most frequent OADs used were aminoglycosides (43 patients) and fluoroquinolones (20 patients). The most frequent carbapenems used were meropenem (141 patients), imipenem (61 patients), and ertapenem (46 patients.

After controlling for confounders, the researchers found that empiric therapy with OADs was not associated with greater 30-day mortality (hazard ratio [HR], 0.75) or with clinical failure at day 14 (adjusted odds ratio, 0.62). In patients discharged alive, the median length of stay was 16 days for patients treated with carbapenems and 14 days for patients treated with OADs; linear regression analysis after adjusting for propensity score showed no significant association between empiric OAD therapy and length of stay (P = .26).

The authors conclude that while the results cannot be interpreted as indicating that OADs and carbapenems are equally effective because of the limited statistical power of the study, the findings suggest OADs might be an option for empiric regimens for some BSI patients, depending on local susceptibility patterns.
Aug 19 Clin Infect Dis study