Stewardship / Resistance Scan for Oct 26, 2022

News brief

Flu contributing to inappropriate antibiotics for respiratory infections

An analysis of patients in a California health system found relatively high rates of flu-associated prescribing of select antibiotics in certain age-groups, researchers reported today in Epidemiology & Infection.

Researchers with Kaiser Permanente and Harvard T.H. Chan School of Public Health estimated influenza-associated prescribing for five antibiotic classes (macrolides, aminopenicillins, protected aminopenicillins, quinolones, and third-generation cephalosporins) from 2010 through 2018 among patients in the Kaiser Permanente of Northern California health system.

Using data on weekly prescribing counts and weekly rates of respiratory samples positive for influenza A and B, they calculated annual rates of influenza-associated prescribing for the different classes per 100,000 individuals in five age-groups—under 5 years, 5 to 17 years, 18 to 49 years, 50 to 64 years, and over 65 years.

The analysis estimated that 3.4% of all macrolide prescriptions, 2.7% of all aminopenicillin prescriptions, 2.2% of all protected aminopenicillin prescriptions, 3.1% of all third-generation cephalosporin prescriptions, and 1.3% of all quinolone prescriptions were influenza-associated.

Corresponding proportions were higher for certain age-groups. For example, influenza accounted for 4.3% of all macrolide prescriptions in patients 50 and older, 3.3% of all aminopenicillin prescriptions in children under 5, and 5.1%, 5.2%, 4.2%, and 3.4% of aminopenicillin, third-generation cephalosporin, quinolone, and protected aminopenicillin prescriptions in patients aged 5 to 17 years, respectively.

Additionally, the relative contribution of influenza to antibiotic prescribing for any respiratory diagnosis without a bacterial indication in patients over 5 was higher than the corresponding relative contribution to prescribing for any diagnosis.

"Our results suggest a modest benefit of increasing influenza vaccination coverage for reducing antibiotic prescribing for the five studied antibiotic classes, particularly for macrolides in ages over 50y, aminopenicillins in children aged under 18y and 3rd generation cephalosporins in ages over 65y, as well as the potential benefit of other measures to reduce unnecessary antibiotic prescribing for respiratory diagnoses with no bacterial indication in persons aged over 5y, both of which may further contribute to the mitigation of antimicrobial resistance," the study authors wrote.
Oct 26 Epidemiol Infect abstract


Private-sector antibiotic use falls in India, but inappropriate use rises

Private-sector antibiotic consumption fell in India over the previous decade, but rates varied widely across states, with some seeing increased inappropriate use of broad-spectrum antibiotics, researchers reported today in JAC-Antimicrobial Resistance.

Using a nationally representative drug sales audit dataset, researchers with the Public Health Foundation of India and Boston University School of Public Health calculated annual private-sector antibiotic consumption rates from 2011 through 2019 across national, state, and state-group (high focus [HF] and non-high focus [nHF]) levels. They analyzed consumption across different characteristics, including World Health Organization AWaRE (Access, Watch and Reserve) classification, product type, and essentiality.

Overall, the annual consumption rate of private-sector antibiotics decreased by 3.6% from 2011 through 2019, falling from 10.7 defined daily doses per 1,000 persons per day (DIDs) to 10.3 DIDs. But the proportion of Access antibiotics, which are first-line recommended agents, declined (compound annual growth rate [CAGR], -1.7%) while the proportion of Reserve, or last-resort antibiotics, increased (CAGR, 16.8%), and the Access/Watch ratio fell from 0.59 to 0.49, suggesting increased use of broad-spectrum antibiotics.

Analysis of state-level consumption showed that consumption varied widely, with HF states—those states with weak public health infrastructure and indicators—reporting lower overall rates of consumption but increased inappropriate antibiotic use over time, reflected by an increasing consumption of Watch antibiotics and fixed-dose combinations and a significant decline in Access/Watch ratio.

The study authors say the overall decline in private-sector antibiotic consumption could reflect national regulatory reforms that went into effect in 2014. But they note that the increasing consumption of broad-spectrum Watch antibiotics correlates with comparatively higher rates of resistance to these antibiotics in India.

"The rapid decline in Access/Watch ratios in HF states is a serious concern as these states have a considerable population share and they lag in socioeconomic and health indicators," the authors wrote. "The significant variations of inappropriate use at the state level called for state-specific studies to understand the factors—at the health-system, provider and patient level—that drive inappropriate use."
Oct 26 JAC-Antimicrob Resist study

News Scan for Oct 26, 2022

News brief

Uganda's widening Ebola outbreak tops 100 cases; more deaths reported

Uganda's health ministry today reported 14 more lab-confirmed Ebola cases, pushing the outbreak total to 109. Health officials also reported 2 more deaths, raising the total to 30. Earlier in the outbreak before the first cases were confirmed, the ministry reported 20 suspected cases, all of them fatal.

At a media briefing today, Uganda Health Minister Jane Ruth Aceng Ocero, MBChB, MPH, said 45 people are being treated for their infections.

The World Health Organization (WHO) African regional office said in its latest weekly health emergencies update that Uganda's outbreak has expanded to two more districts, Kampala and Wakiso, raising the number of affected locations to seven. It warned that further expansion of the outbreak is possible, given that high-risk contacts have been identified for follow-up in five yet-unaffected districts.

Uganda is making progress with case management but needs more isolation units, ambulances, human resources, and funding to battle the outbreak, the WHO said.

Meanwhile, Doctors Without Borders (MSF) said yesterday that it is stepping up its response. It said its teams will expand to help with the response, including medical care, in Kampala.

MSF is currently supporting the treatment of sick people in Mubende, the outbreak's epicenter. One 40-bed treatment facility has been completed there, and another 40-bed unit with the capacity to provide intensive are is under construction in the same area. An 8-bed unit in Madudu is up and running. MSF also said it stands ready to help with clinical trials of vaccines and treatments for the less common Sudan Ebola virus that is fueling the country's outbreak.
Oct 26 Uganda health ministry update
Oct 26 Uganda health ministry tweet
Oct 25 WHO African regional office weekly health emergencies report
Oct 25 MSF update


Alpha, Delta, and Omicron patients may exhale more viruses

A study today from researchers at the University of Maryland determined that patients infected with COVID-19 variants Alpha, Delta, and Omicron—including those fully vaccinated and boosted—shed significantly more viral RNA copies into exhaled breath aerosols than patients infected with ancestral strains and other variants.

The study appears in Clinical Infectious Diseases and adds to evidence of increased transmissibility of the Alpha, Delta, and Omicron variants. The study used 30-minute respiratory samples collected via a Gesundheit-II exhaled breath aerosol sampler from 93 participants who had confirmed COVID-19 infections. Of those, 32 were fully vaccinated and 20 boosted. The participants were tested from June 2020 through March 2022.

According to the authors, 4 Alpha, 3 Delta, and 29 Omicron patients shed significantly more viral RNA copies into exhaled breath aerosols than the 57 people infected with ancestral strains and variants.

The increase in viral shedding may have been at least partly due to participant behavior while in the Gesundheit machine. The authors said Delta and Omicron patients coughed more frequently than those infected with Alpha, ancestral strains, and other variants. Omicron patients also generally reported more upper and lower respiratory symptoms than the other volunteers.

"These data indicate that a characteristic of highly transmissible variants is a high rate of viral shedding into aerosols," the authors concluded. "This evidence for convergent evolution of increased viral aerosol shedding is consistent with a dominant role for airborne transmission (inhalation of viral aerosols regardless of distance that the aerosol traversed) in the spread of COVID-19."
Oct 26 Clin Infect Dis


Omicron BA.2 subvariant appears to be less severe than other strains

A study yesterday in JAMA Network Open suggests that the SARS-CoV-2 Omicron BA.2 subvariant carries a significantly lower risk of death than that of Delta and the original Omicron strain, B.1.1.529.

Led by researchers at Massachusetts General Hospital and Harvard Medical School, the study involved 102,315 COVID-19 cases in adults and children in New England diagnosed from Mar 3, 2020, to Jun 20, 2022. Average patient age was 44.2 years, 62% were women, 76.4% were White, and 20.3% of the cases were Delta, 51.4% were Omicron, and 28.3% were BA.2.

Amid Delta, 48.5% of patients had received a primary COVID-19 vaccine series, and 44.7% were unvaccinated, while during Omicron predominance, 65.9% had received a booster dose. Also, fewer people had previous infections during the Delta wave (1.8%) than in the Omicron (6.4%) and BA.2 (5.3%) surges.

COVID-19 30-day death rates were 0.7% for Delta, 0.4% for Omicron, and 0.3% for Omicron BA.2. The adjusted odds ratio (aOR) of death from Delta relative to BA.2 was 2.07 (95% confidence interval [CI], 1.04 to 4.10), and for Omicron it was 2.20 (95% CI, 1.56 to 3.11).

The risk of hospitalization with Delta was significantly greater than that of BA.2 (aOR, 3.84; 95% CI, 2.93 to 5.02). Omicron was also more likely to lead to hospitalization than BA.2 (OR, 2.71; 95% CI, 2.42 to 3.02).

Likewise, intensive care unit admission was six times higher with a Delta infection than with BA.2 (OR, 6.12; 95% CI, 2.57 to 14.5), and with Omicron it was triple (OR, 3.06; 95% CI, 2.28 to 4.10). The relative risk of invasive ventilation was more than quadruple and triple, respectively, with Delta (OR, 4.36; 95% CI, 2.56 to 7.41) and Omicron (OR, 3.55; 95% CI, 2.61 to 4.84).

"After having accounted for a variety of confounding factors associated with SARS-CoV-2 outcomes, the Omicron BA.2 subvariant was found to be intrinsically less severe than both the Delta and Omicron variants," the study authors wrote.
Oct 25 JAMA Netw Open study

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