Stewardship / Resistance Scan for Sep 09, 2020

News brief

IDSA releases new treatment guidance for drug-resistant pathogens

The Infectious Diseases Society of America (IDSA) yesterday released new guidelines for the treatment of three common antibiotic-resistant pathogens.

The goal of the guidelines, the first in a series of narrowly focused guidance documents that IDSA will be publishing on multiple platforms, are to assist clinicians in selecting antibiotic therapy for extended-spectrum beta-lactamase–producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with difficult-to-treat resistance (DTR-P aeruginosa). The three pathogens have been designated as serious or urgent threats by the Centers for Disease Control and Prevention, cause a wide variety of infections, and have limited treatment options.

Created as an alternative to comprehensive clinical practice guidelines, which can take years to produce and publish, the guidance was developed by a panel of six infectious diseases specialists with expertise in antibiotic-resistant bacterial infections to address specific clinical questions about difficult-to-manage infections that are not covered by current guidelines, and is based on a review of the literature.

"Clinicians rely on evidence-based guidelines from other clinicians who have considered the literature and available data," panel co-chair Cornelius J. Clancy, MD, VA Pittsburgh Healthcare System's chief of infectious diseases and an associate professor of medicine and director of the XDR Pathogen Lab at the University of Pittsburgh, said in an IDSA press release. "This guidance provides clinicians with real-word recommendations on how to deal with real-world problems."

The guidance will be updated as new data emerge, and future iterations will address other resistant pathogens.
Sep 8 IDSA guidance
Sep 8 IDSA press release

Study: Discordant antibiotics fairly common for bloodstream infections

A study led by researchers with the National Institutes of Health found that nearly one in five patients with bloodstream infections in US hospitals received discordant antibiotic therapy, which was associated with antibiotic-resistant pathogens and increased mortality. The results appeared yesterday in The Lancet Infectious Diseases.

The retrospective cohort analysis of electronic health record (EHR) data from 131 US hospitals looked at all patients with suspected and subsequently confirmed bloodstream infections who were treated empirically with antibiotics from 2005 through 2014.

The researchers defined empiric antibiotic therapy as discordant if the bloodstream isolate from a patient did not display in-vitro susceptibility to any systemic antibiotic administered in the day of blood culture sampling. Using the EHR data, they estimated the prevalence of discordant antibiotic therapy, identified predictors of receiving discordant therapy, and calculated the adjusted odds ratio for the relationship between discordant therapy and in-hospital mortality.

Of the 21,608 patients who received empiric antibiotics on the first day of blood culture collection, 4,165 (19%) received discordant empiric antibiotic therapy based on retroactive assessment of final susceptibility results. Of those patients, 1,958 (49%) had antibiotic-resistant bloodstream isolates. Most patients who received discordant therapy had infections caused by resistant Enterobacterales or Staphylococcus aureus. Patients infected with antibiotic-resistant pathogens were nine times more likely to receive discordant empiric therapy than those with susceptible infections (adjusted odds ratio, 9.09; 95% confidence interval [CI], 7.68 to 10.76).

Discordant empiric therapy was independently associated with a significantly increased risk of mortality (adjusted odds ratio, 1.46; 95% CI, 1.28 to 1.66), which was unaffected by the presence or absence of resistance, sepsis, or septic shock.

The study also found that discordant empiric therapy was not significantly affected by hospital-level characteristics, a finding the authors say suggests that the problem is widespread, and that any efforts to optimize empiric prescribing would need to be implemented on a large scale.

"Such optimisation is likely to improve survival in all bacteraemic patients," they wrote. "Early identification of bloodstream pathogens, especially Enterobacterales and S aureus, and associated resistance profiles could improve outcomes in patients with bloodstream infections on a population level."
Sep 8 Lancet Infect Dis abstract

News Scan for Sep 09, 2020

News brief

Study shows lower case-fatality rate in COVID-19 second wave

A new study in Transboundary and Emerging Disease calculated the case-fatality rate (CFR) of COVID-19 infections in 53 countries or regions that experienced a second wave—or resurgence—of coronavirus activity, and found a significantly lower death rate among all confirmed cases than in the first wave.

This is the first study to compare the CFR in the first and second waves of the pandemic.

Researchers from Hong Kong based the study on daily confirmed COVID-19 cases and deaths for 216 countries or regions, during February of 2020 through August 2020, and weekly influenza confirmations during 2015 to the current week of 2020, from the World Health Organization (WHO). They defined the first wave as cases before Jun 1, and deaths before Jun 10, and second wave as any case after Jun 1 or any death after Jun 10.

Forty-three of the 53 regions studied showed lower CFRs during the second wave than the first. The 10 countries or regions with higher CFRs in the second wave were mostly in the Southern hemisphere (eg, Peru, Chile) and had reported mild first waves of the pandemic.

The authors offer possible explanations for the higher CFR in the first wave, including a harvest effect, where the elderly and infirm were first infected. They also said countries improved testing and surveillance, which helped them record more mild cases. Finally, they said younger people were more likely to be infected in subsequent waves and were less likely to die from infections.

Flu data from the WHO also showed steep declines in flu transmission during both waves, a sign that physical distancing measures reduced influenza spread.

"Although the lower CFR in the second phase is a positive sign to suggest the decrease[d] severity of COVID-19 infections, the shift to younger age groups could bring more difficulty in containing the pandemic," the authors concluded. "We also need to stay vigilant for the potential rebound of influenza outbreaks as many countries or regions are planning to lift social distancing control measures."
Sep 6 Transbound Emerg Dis study

Groups emphasize pandemic risk for Chinese swine H1N1 flu subtype

Three global health groups today issued a joint statement that strongly urged countries to be aware of the pandemic potential for an H1N1 swine influenza subtype circulating in Chinese pigs. The statement is from the United Nations Food and Agriculture Organization (FAO), the World Organization for Animal Health (OIE), and the World Health Organization (WHO).

The 1C.2.3 ("G4") genetic clade of H1N1 swine influenza was first identified by Chinese researchers in 2016 and has become the dominant genotype circulating in China's pigs. Two variant H1N1 cases involving the subtype have recently been detected in humans, and a small seroprevalence study in Chinese swine workers suggested that 10% had been exposed to the virus. The WHO Collaborating Center in China has developed a candidate vaccine virus targeting the strain.

Keith Sumption, DVM, PhD, the FAO's chief veterinary office, said though there are limited data on human infections and circulation of the virus in pigs, heightened awareness is needed for a number of reasons, including a recent study from China showing that the virus has characteristics linked to increased ability for zoonotic transmission.

"The viruses have some genetic markers to suggest human infection is possible; they can replicate in human airway cells, and viruses can be spread via respiratory droplets passed between ferrets," he said.

The group urged countries to rapidly assess and share their latest surveillance data.
Sep 9 FAO, OIE, and WHO statement