News Scan for Apr 05, 2021

News brief

B117 shows similar aerosol stability as other strains

The COVID-19 B117 strain, which was first identified in the United Kingdom, has similar aerosol stability compared with three other COVID strains, so transmissibility differences are most likely due to other factors, according to a study last week in The Journal of Infectious Diseases.

The researchers looked at an isolate of B117 as well as three other COVID-19 strains (hCoV-19/France/IDF0372/2020, hCoV-19/USA/NY-PV08449, and hCoV-19/USA/WA-1/2020), testing the effects of light, humidity, and temperature on aerosols from a simulated respiratory tract lining fluid (sRTLF) in a rotating drum chamber.

No difference was identified in the absence of sunlight at 20°C or 40°C, but a small significant difference was seen in some aerosols when exposed to sunlight at 20°C and 20% relative humidity. Test conditions included 10°C and 30°C in darkness and full-intensity sunlight at 70% relative humidity.

"For each isolate, mean k_infectivity values [the decay constant for viral infectivity] were significantly higher in simulated sunlight than in darkness," the researchers write, noting that the data suggest all four would be "rapidly inactivated" by real-world sunlight. "There were no differences in the decay constants between isolates in darkness at either 20°C or 40°C, with a mean time for a 90% loss of viral infectivity across all dark conditions of 6.2 hours."

Aerosol transmission is affected by more than decay rate, though, the researchers cautioned. The amount of virus emitted, the origins of the viral particles (eg, lung vs saliva), mutations changing which cells the virus affects, and other factors can change transmissibility.
Apr 2 J Infect Dis study

Study: Venous thromboembolism not increased in COVID outpatients

Thirty-day incidence of venous thromboembolism (VTE) does not appear to have a greater association with outpatients infected with COVID-19 compared with non-infected adults, according to a research letter today in JAMA Internal Medicine.

The researchers looked at 220,588 adults tested for COVID-19 from Feb 25 to Aug 31, 2020, in the Kaiser Permanente Northern California health plan. After excluding patients who were asymptomatic at the time of testing or who had previously received anticoagulants, 26,104 (11.8%) were included in the positive COVID subgroup.

VTE occurred in 198 patients with a positive COVID test (0.76%) and 1,008 people with a negative COVID-19 test (0.52%). Of the 117 who had an outpatient COVID test and then developed VTE, 89 (76.1%) also needed hospitalization later on.

Overall, 30-day VTE incidence was 4.7 per 1,000 individuals who tested positive for COVID-19 versus 1.6 in those who tested negative. COVID patients who needed hospitalization were more associated with VTE compared with those who didn't have COVID but were hospitalized (5.8 vs 3.0 cases per 1,000 individuals tested), but no significant difference was seen in incidence for infected versus non-infected outpatients.

"These findings suggest that VTE incidence outside of the hospital is not significantly increased with SARS-CoV-2 infection and argue against the routine use of outpatient thromboprophylaxis outside of clinical trials," the researchers write. Because COVID-19 symptoms have been seen in individuals months after the original diagnosis, however, the researchers add that studies may also need to look at 90-day VTE potential.
Apr 5 JAMA Intern Med research letter

Campylobacter in raw milk sickens 5 in Washington state

Health officials in Washington state said they have identified five campylobacteriosis infections in people who recently drank raw milk from a creamery in Sequim, according to an Apr 2 Washington State Department of Health (WSDH) statement.

The raw milk from Dungeness Valley Creamery was bought in four different counties, and the company has voluntarily recalled all of its raw milk with a "best buy" date of Apr 13 or earlier, due to potential contamination with Campylobacter.

Scott Lindquist, MD, MPH, state epidemiologist for communicable diseases, said, "Unpasteurized raw milk can carry harmful bacteria and germs. Foodborne illnesses can be caused by many different foods; however, raw milk is one of the riskiest."

Campylobacter infection symptoms include fever, diarrhea, nausea, and malaise. Patients often recover on their own, but some, such as infants, seniors, and people with weakened immune systems, can experience more severe symptoms.
Apr 2 WSDH statement

Stewardship / Resistance Scan for Apr 05, 2021

News brief

Hospitals worldwide display wide variation in antibiotic consumption

A worldwide analysis of hospital antibiotic prescribing patterns found considerable differences between countries and regions in proportional use of Access, Watch, and Reserve (AWaRe) antibiotics, researchers reported today in the Journal of Antimicrobial Chemotherapy.

Using data collected in 2015, 2017, and 2018 by the Global Point Prevalence Survey on Antimicrobial Consumption and Resistance (Global-PPS), researchers from the University of Antwerp analyzed hospital antibiotic use at 664 hospital in 69 countries. They categorized inpatient antibiotic consumption using the AWaRe classification system, introduced by the World Health Organization (WHO) in 2017 to provide an indirect indication of the appropriateness of antibiotic use at national and global levels, then calculated proportional Access, Watch, and Reserve use by region and country. The final dataset included 80,671 patients who received at least one systemic antibiotic.

Regional use of Access antibiotics, which are first- and second-line agents that should be widely available and affordable, ranged from 28.4% in West and Central Asia to 57.7% in Oceania. Regional use of Watch antibiotics—broad-spectrum drugs that are not recommended for routine use because of their higher potential for resistance—was lowest in Oceania (41.3%) and highest in West and Central Asia (66.1%). The overall use of Reserve antibiotics, which are last-resort antibiotics, ranged from 0.03% in sub-Saharan Africa to 4.7% in Latin America.

Stratified by World Bank country classification, low-income countries had the highest Access use (62.8%) and the lowest Watch antibiotic use (36%). Beyond that, the proportion of Watch antibiotic use was 63.4% in lower-middle-income countries, 62.2% in upper-middle-income countries, and 53.1% in high-income countries. Reserve antibiotic use was highest in upper-middle-income countries (3.0%).

By country, Access use was highest in Guinea (66.7%) and lowest in Armenia (12.1%), while Watch use was highest in Armenia (87.9%) and lowest in Guinea (32.1%). Reserve antibiotic use was highest in Argentina (12.6%), India (7.8%), and Brazil (7.1%). The median Access-to-Watch ratio was 0.7.

"We observed large heterogeneity in AWaRe prescribing at country, regional and income levels," study authors conclude. "Further research on local levels, integrating contextual information, could usefully explore some of the drivers behind the prescribing patterns reported here."
Apr 5 J Antimicrob Chemother study

Dental antibiotic prescribing significantly higher in US

A comparison of dental antibiotic prescribing rates found that US dentists prescribe antibiotics much more frequently than those in England, Australia, and Canada, researchers reported today in Infection Control & Hospital Epidemiology.

The population-level analysis of dental antibiotic prescribing looked at pharmacy-dispensed systemic antibiotic prescriptions by dentists in the United States, England, Australia, and British Columbia in 2017. The three outcomes analyzed for each country were the rate of antibiotic prescribing per 1,000 population, the relative proportions of each antibiotic class, and the prescribing rate per 1,000 population of each antibiotic type.

Dentists in the United States prescribed 23.6 million antibiotic items in 2017, compared with 3 million in England, 0.8 million in Australia, and 0.3 million in British Columbia. US dentists also had the highest prescribing rate (72.6 antibiotic items per 1,000), more than twice the rate of Australia, which had the lowest (33.2 per 1,000). Penicillins, mainly amoxicillin, were the most prescribed antibiotic class in each country (highest at 80.5% in British Columbia and lowest at 66.8% in England). Lincosamides (eg, clindamycin) comprised the second most frequently prescribed class of antibiotics in the United States (14.3%) and British Columbia (12.4%), while nitroimidazoles (eg, metronidazole) comprised the second most frequently prescribed class of antibiotics in England (28.4%) and Australia (13.2%).

Broad-spectrum agents, such as amoxicillin-clavulanic acid and azithromycin, were most frequently used in Australia and the United States, respectively.

The study authors say the variation in dental antibiotic prescribing rates among the four countries does not seem to be explained by differences in dental health, but may be related to differences in use of prophylactic antibiotics in certain patients to reduce infection risk during invasive procedures—a frequent practice among US dentists. Whatever the reasons, they say the variation, and the frequent, unnecessary use of broad-spectrum antibiotics in all countries, is a concern.

"Dental antibiotic stewardship programs are urgently required as part of national responses to delivering the WHO global action plan on tackling antimicrobial resistance," they write. "Further research to understand locally relevant factors driving unnecessary dental antibiotic prescribing in each country is needed to support the development of context-appropriate stewardship solutions to the global problem of antibiotic resistance."
Apr 5 Infect Control Hosp Epidemiol abstract