News Scan for Jun 28, 2022

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Study: In most young adults, COVID-19 infectious period lasts only 5 days

A new study from researchers at Boston University (BU) shows that, for all but 17% of healthy, vaccinated young adults, the infectious period for COVID-19 from the Delta and Omicron variants was 5 days. The study was recently published in Clinical Infectious Diseases.

The study involved 92 SARS-CoV-2 RT-PCR–positive participants who had all been fully vaccinated with an initial series of COVID-19 vaccine. Tests showed 17 (18.5%) were infected with Delta and 75 (81.5%) with Omicron.

The researchers conducted daily anterior nasal swabs for at least 10 days following a positive test for reverse transcription-polymerase chain reaction (RT-PCR) test and culture and with antigen rapid diagnostic testing (RDT) on a subset of individuals. They found all but 17% of participants converted by day 6 and were no longer considered infectious.

The authors of the study said their findings reaffirm the Centers for Disease Control and Prevention guidance, which says, following detection, COVID-19 patients should isolate for 5 days, then wear a mask when around others for another 10 days.

"As isolation can have a significant impact on both the economy of a country and the mental health of its citizens, it is imperative to make efforts to reduce isolation periods while simultaneously preventing infectious individuals from spreading the disease," said corresponding author Tara Bouton, MD, MPH, said in a press release.

The authors said there was no differences seen in variants and length of time to convert, and in the study subset who used an antigen RDT in days 5 through 7 following diagnosis, RDT had perfect negative predictive value and sensitivity when compared to culture.
Jun 23 Clin Infect Dis study
Jun 27 Boston University press release


US study highlights elevated risk of resistant urinary tract infections

A multicenter study of US patients who presented to the emergency department (ED) for a complicated urinary tract infection (cUTI) caused by Enterobacterales bacteria found high levels of resistance to the most commonly used oral antibiotics, researchers reported late last week in Open Forum Infectious Diseases.

To quantify the prevalence of resistance and co-resistance to commonly used oral cUTI agents across US regions, researchers analyzed data from the Premier Healthcare Database on adult cUTI patients with an Enterobacterales pathogen who presented to the ED for care from 2013 through 2018. Dividing the cohort into patients who were treated only in the ED and those who were admitted to the hospital, the researchers determined the proportion of patients within each US census region with resistance and co-resistance to fluoroquinolones, trimethoprim-sulfamethoxazole, nitrofurantoin, and third-generation cephalosporins.

There were 60,006 patients in the ED-only cohort and 86,743 in the inpatient cohort; the ED-only cohort was younger, less likely to be male, and had fewer baseline comorbid conditions. Escherichia coli was the most predominant Enterobacterales pathogen in both cohorts, accounting for roughly 33% of all cases combined. In the ED cohort, 40% to 50% of cUTIs in each US census region displayed resistance to at least one agent, and 10% to 18% in each region had resistance to two or more agents. Resistance to nitrofurantoin and fluoroquinolones exceeded 15%, and resistance to trimethoprim-sulfamethoxazole exceeded 25%.

In the inpatient cohort, 55% to 65% of cUTIs in each region were resistant to at least one agent, and 25% to 35% were resistant to two or more. Resistance to nitrofurantoin and fluoroquinolones exceeded 30%.

"These findings have important clinical implications," the study authors wrote. "Given the high observed rates of resistance observed in both cohorts, adult patients who present to the ED with a cUTI have an elevated risk for receiving an inappropriate empiric agent if prescribed a fluoroquinolone, TMP-SMX, nitrofurantoin, or an oral third generation cephalosporin."

They added that the findings indicate that many cUTI patients will require intravenous antibiotics for their treatment, which highlights the clear need for new oral antibiotic options.
Jun 24 Open Forum Infect Dis abstract

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