A study of US nursing homes found that two thirds of long-term residents were prescribed at least one antibiotic during their stay, researchers reported yesterday in the Journal of Infectious Diseases.

Using Medicare Part D claims data, researchers from the Brown University School of Public Health conducted a longitudinal, retrospective study of antibiotic use in Medicare beneficiaries who had spent at least 101 days in a nursing home (NH) from 2013 through 2017. They calculated period-prevalence estimates to assess any use of antibiotics during these long-stay NH episodes, along with the rate of antibiotic prescribing and antibiotic days of therapy (DOT).

Among 1,375,062 long-stay NH residents (67.3% female, 80.5% White), 66.2% were prescribed at least one antibiotic during their stay. Residents who received an antibiotic were slightly older (82.6 vs 81.9 years) and had longer stays (712.3 vs 451.7 days) than those who received no antibiotics.

The overall rate of antibiotic prescribing was 387 days per 1,000 person-years, and the rate of DOTs was 41.6 per 1,000 days of care. The most prevalent antibiotic classes were fluoroquinolones (36.2%), sulfonamides and related agents (16.2%), and first-generation cephalosporins (15.9%). Levofloxacin (22.1%), ciprofloxacin (19.4%), and trimethoprim-sulfamethoxazole (15.9%) were the most prevalent antibiotics.

The authors say the study overcomes some of the limitations of previous estimates of antibiotic use in US nursing facilities, most of which have relied on cross-sectional data and 1-day point-prevalence surveys.

"Our nationally representative results provide important foundational evidence on antibiotic prescribing in U.S. NHs and can inform future research, antibiotics stewardship initiatives, and policies to improve prescribing practices," the authors wrote.

The combined incidence of gonorrhea, chlamydia, and syphilis was cut by two-thirds among men who have sex with men (MSM) and transgender women who were taking doxycycline post-exposure prophylaxis (doxy-PEP), according to the results of a randomized trial published today in the New England Journal of Medicine.

The open-label randomized trial involved 501 MSM and transgender women (67% White, 30% Hispanic or Latino, 11% Asian or Pacific Islander, 7% Black) who were taking post-exposure prophylaxis against HIV (the PrEP cohort) or were persons living with HIV (the PLWH cohort) and had had gonorrhea, chlamydia, or syphilis infections in the past year.

The participants were randomly assigned in a 2:1 ratio to take 200 milligrams of doxycycline within 72 hours of condomless sex or receive standard care. Participants underwent quarterly sexually transmitted infection (STI) testing, and the primary outcome was the incidence of at least one STI per quarter.

The incidences of the three evaluated STIs were lower with doxycycline than with standard care. In the PrEP cohort (327 participants), the incidence of gonorrhea fell by 55% (relative risk [RR], 0.45; 95% confidence interval [CI], 0.32 to 0.65), chlamydia by 88% (RR, 0.12; 95% CI, 0.05 to 0.25), and syphilis by 87% (RR, 0.13; 95% CI, 0.03 to 0.59) among those taking doxycycline. In the PLWH cohort (174 participants), incidence fell by 47% (RR, 0.43; 95% CI, 0.26 to 0.71), 74% (RR, 0.26; 95% CI, 0.12 to 0.57), and 77% (RR, 0.23; 95% CI, 0.04 to 1.29), respectively.

Five grade 3 adverse events and no serious adverse events were attributed to doxycycline. Of the participants with available gonorrhea cultures, tetracycline-resistant gonorrhea occurred in 5 of 13 in the doxycycline groups and 2 of 16 in the standard-care groups.

The efficacy of the intervention led the data and safety monitoring board to stop the trial early in May 2022 and recommend that all participants be offered doxy-PEP. The results were initially announced at the 2022 International AIDS Conference.

"These results showed effectiveness of doxy-PEP among MSM regardless of HIV status in a socioeconomically and racially diverse population," the trial investigators wrote.

French officials recently posted an update on an mpox cluster in the Center-Val de Loire region, with 17 cases reported since the first of the year, including 14 since March 1. All occurred in men who have sex with men who had several partners but didn't attend any common events.

Five of the patients had received two mpox vaccine doses in 2022. Also, five had received one smallpox dose during childhood, plus one dose in 2022.

Given the high proportion of vaccinated people in the cluster, 59%, Public Health France and its regional partners investigated the development, finding that the proportion of vaccinated cases is higher than the 25% observed at the national level between October and February.

"It is appropriate to await the results of real-life efficacy studies which will allow better interpretation of these data. To date, there is little perspective on the efficacy of 3rd generation vaccines against mpox infection," Public Health France said in its statement.

In other mpox developments, the European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO) European regional office yesterday posted a joint update on mpox, which reported 28 new cases from 7 countries since the last update 4 weeks ago. Sixteen of the cases are part of the French cluster. Six were from Spain. Other countries reporting cases are Portugal, the Netherlands, Switzerland, Greece, and Malta.

An epidemiologic investigation into a Chilean man's H5 avian flu infection has found that environmental exposure is the most likely source, the World Health Organization (WHO) said today in an update. The 53-year-old man's infection marked the second such case from South America.

The man is from Antofagasta region in northern Chile. He had no underlying health conditions or recent travel. His symptoms began on March 13, and he was hospitalized on March 22 after his condition worsened. He was admitted to the intensive care unit, where he received oseltamivir and was placed on a ventilator due to pneumonia. A bronchoalveolar swab was positive for an unsubtypeable influenza A virus, which was further characterized as H5.

So far, contact monitoring hasn't identified any related infections, though one health worker has respiratory symptoms and is undergoing further testing.

The WHO said between December and February, highly pathogenic avian flu was tested in Antofagasta region wild birds (pelicans and penguins) and sea mammals (sea lions). The WHO said the man may have had environmental exposure in areas close to his house where either sick birds or mammals were found.