Stewardship / Resistance Scan for Dec 17, 2018

News brief

Study finds substantial declines in children's outpatient antibiotic use

Data from three large health plans shows a substantial decline in outpatient antibiotic use in children from 2010 through 2014, according to a study today in Pediatrics.

For the study, researchers analyzed pharmacy claims data from three commercial health plans (Plans A, B, and C) in three different regions of the United States, covering children between 3 months and 18 years of age. The same research team has been monitoring the data since 2000, and a previous study had found that the substantial downward trend in antibiotic use among children since 2000 had begun to plateau by 2009-2010. To determine whether antibiotic use has continued to decline or remain stable, the researchers calculated population-based antibiotic-dispensing rates for the three health plans for each study year from 2000 through 2014.

The results showed clear and substantial additional declines in antibiotic use among children in all age groups in the three health plans from 2009-2010 through 2013-2014. Looking at 2000-2001 through 2013-2014, the researchers found overall declines across all three health plans of 40% to 50% among children under the age of 6, who have the highest rates of antibiotic use of any age group. Declines in the range of 20% to 40% were observed in older children and adolescents. Consistent with the findings of the previous studies, antibiotic prescribing rates were markedly lower in Plan B, an integrated delivery health system plan located in the Mountain West.

The results also showed that the fraction of antibiotic prescribing associated with diagnoses of viral illnesses decreased in all age groups, and that use of second-generation macrolides and cephalosporins—neither of which are considered first-line treatment for common pediatric infections—declined from 2009-2010 through 2013-2014, after marked increases the decade before.

Though they acknowledge that a substantial fraction of antibiotic prescribing in all age groups remains unnecessary and that further reductions are possible, the authors of the study conclude, "We believe that child health professionals can be justifiably proud of the major change in practice that has occurred in outpatient prescribing of antibiotics."
Dec 17 Pediatrics study

Study shows C diff spores persist in toilet water and on bathroom surfaces

A new study by researchers from the University of Oklahoma College of Public Health suggests that toilets may be a persistent source of environmental Clostridioides difficile contamination. The findings appear in the American Journal of Infection Control.

In the experimental study, the researchers seeded a flushometer-style toilet in a sealed chamber with a non-pathogenic strain of C difficile spores. The toilet was then flushed 24 times, and the researchers collected post-flush bowl water samples to measure C difficile in the toilet water. They also evaluated large droplets on toilet and bathroom surfaces and air samples to measure environmental contamination and the presence of bacteria in aerosol from the toilet plume.

The researchers captured C difficile spores in all post-flush water samples in all trials, indicating persistent contamination even after 24 flushes. In addition, C difficile spores detected in large droplets on toilet and bathroom surfaces accumulated over the 24-flush period. Droplet nuclei spore bioaerosol was produced over at least 12 flushes.

"These results demonstrate that toilets contaminated with C difficile spores will produce numerous large droplet and droplet nuclei bioaerosols that can contaminate surfaces close to and distant from the source," the authors of the study write. "Further, the microbial contamination will persist in the bowl water for many flushes after initial contamination and produce bioaerosol with each flush."

The authors say the results have significant implications for public access environments where people shedding C difficile, or other gastrointestinal pathogens, may contaminate a toilet that is subsequently used by other people.
Dec 14 Am J Infect Control study

News Scan for Dec 17, 2018

News brief

With 7 more AFM cases, US outbreak grows to 165 cases in 36 states

The US Centers for Disease Control and Prevention (CDC) recorded 7 new confirmed cases of acute flaccid myelitis (AFM) this past week, bringing 2018's total to 165 confirmed cases.

According to the CDC, the 165 cases are among the total of 320 reports that it received regarding patients under investigation). CDC and local health departments are still investigating some of those suspected cases.

For the third week in a row, Texas reported new cases and now has 24 confirmed cases, the most of any state. Colorado has 15, Ohio 12, and New Jersey 10. Thirty-two other states report at least 1 case of the rare, polio-like illness. 2018 has seen the most AFM cases of any outbreak year since 2014, when the CDC began tracking the condition. Since the AFM has clustered every 2 years in the United States.

AFM typically affects the gray matter surrounding the spinal cord and leads to muscle weakness in pediatric patients. In 90% of patents, symptoms develop following a mild respiratory illness.
Dec 17 CDC update

Farm linked to romaine E coli outbreak recalls additional produce

Adam Brothers Farming, Inc., the California farm recently identified as a likely source of Escherichia coli O157:H7 outbreak linked to romaine lettuce, has also recalled its red leaf lettuce, green leaf lettuce, and cauliflower, though no illnesses have been connected to those products.

In a Dec 13 press release, the company said the recalled products were harvested from Nov 27 to Nov 30 on particular fields and that it was taking the step out of an abundance of caution.

The cauliflower was distributed to 10 states, Mexico, and Canada. Both types of lettuce were distributed to six states and Canada. And red leaf lettuce was distributed to a wholesaler in Minnesota and in Mexico.

The company said the produce may have come in contact with filtered, treated water that came from a reservoir from which a sediment sample tested positive for E coli. It added that the filtered, treated water was negative for E coli.
Dec 13 Adam Bros press release

Early CDC estimate shows increase in flu vaccine uptake

A survey that the CDC uses to track flu vaccination suggests that, as of the middle of November, immunization levels are running ahead of last season at this time.

In a Dec 14 FluVaxView update, the CDC said the National Immunization Survey-Flu shows that coverage in children is at 45.6%, reflecting an increase of 6.8 percentage points compared with this time last season, mainly owing to increased uptake in kids ages 12 and younger. Coverage for adults is at 44.9%, up 6.4 percentage points from this point last season.

The child and teen estimates are based on a random cell-phone surveys. Interviews were conducted from Oct 1 to Nov 17 and included 24,083 children for whom the parent reported a vaccination status. The adult portion of the estimate is based on an Internet panel survey that was conducted during the first half of November. It includes data from 4,286 respondents who answered the flu vaccination question.

As of Nov 30, vaccine makers had distributed 163.8 million doses, up from 155 million for all of last season.

The CDC said flu vaccination is the best way to prevent deaths and hospitalization from flu and that people not yet immunized should get vaccinated as soon as possible.
Dec 14 FluVaxView update

Quadrivalent flu shot shown 51% effective in young children

Two doses of an inactivated quadrivalent influenza vaccine made by Sanofi (Vaxigrip Tetra) was effective in young children, even against mismatched strains, according to a study in both Northern and Southern Hemisphere children that spanned four flu seasons, two in each hemisphere. An international research team led by Sanofi reported its findings on Dec 14 in Vaccine.

Healthy children ages 6 to 35 months who had not previously been vaccinated against flu received two full doses of Vaxigrip Tetra 28 days apart, placebo, or an investigational trivalent inactivated vaccine that contained an influenza B strain from an alternate lineage. The trial was conducted in Latin America, Asia, Africa, and Europe during the Northern Hemisphere's 2014-15 and 2015-16 flu seasons and the Southern Hemisphere's 2014 and 2015 flu seasons.

The efficacy analysis included 4,980 children who completed the study protocol. Vaccine efficacy for Vaxigrip Tetra against any influenza A or B strain for was 51.0% (97% confidence interval [CI], 37.36% to 61.86%) and was 68.4% (97% CI, 47.07% to 81.92%) against vaccine-matched strains. The authors noted that only about one quarter of confirmed flu infections involved vaccine-similar strains.

Safety patterns were similar for Vaxigrip Tetra, placebo, and the investigational vaccine, though injection-site reactions were slightly more common for Vaxigrip Tetra than placebo.

The team said the findings are similar to reports for another full-dose inactivated quadrivalent vaccine in the same age-group. "Together, the results provide convincing evidence that inactivated quadrivalent influenza vaccines are effective at preventing influenza in children aged 6–35 months," they concluded.
Dec 14 Vaccine study

Study: More mumps in Australia despite high vaccination coverage

Even among communities with high vaccination coverage rates, a protracted mumps outbreak grew in size and frequency in Western Australia in 2015 and 2016, according to a new study published in The Lancet Infectious Diseases.

The population-based surveillance study looked at mumps cases reported in 2015 and 2016 in the Western Australia Infectious Diseases Database, and compared the case information with data from the Australian Childhood Immunization Register.

Aboriginal people accounted for most of the case-patients in the outbreak, representing 798 of 893 cases (89%). "The risk for Aboriginal Australians to acquire mumps was 37 times higher than the risk for non-Aboriginal Australians living in the same areas, despite high vaccination coverage in both groups," the authors said.

Patients ages 15 to 19 years were most likely to be diagnosed as having mumps, despite a high vaccination rate among them. Of the 419 patients in the study between the ages of 1 and 19, 89% were fully vaccinated with two doses of measles, mumps, and rubella (MMR) vaccine, and 7% had at least one dose.

The study authors said their findings suggest the need for a third additional dose of MMR vaccine among some populations, adding that Aboriginals may be more prone to mumps because of waning immunity, immune escape, large household size with suboptimal hygiene, and high levels of mobility and social interaction.

In an accompanying commentary, Helen S. Marshall, MD and Stanley Plotkin, MD, write that waning immunity was the likely cause of these outbreaks. Unlike measles and rubella, mumps continues to flare in highly vaccinated populations, and literature shows that as many as 25% of vaccine recipients have waning immunity to mumps after receiving the vaccine. The experts warn that a third dose of MMR may not be feasible or economical in most outbreak settings.
Dec 14 Lancet Infect Dis study
Dec 14 Lancet Infect Dis commentary