The United Kingdom's National Health Service (NHS) announced yesterday that pharmaceutical companies applying for a contract through its antibiotic subscription model will have to prove they are meeting responsible antibiotic manufacturing standards.

The first-of-its kind NHS Antimicrobial Product Subscription Model pays companies a fixed annual fee for antibiotics based on their value to the NHS rather than on the volume of antibiotics sold. 

The aim of the program is to incentivize research and innovation in the antibiotic development sector by providing a guaranteed financial return. Antibiotic development has lagged in recent years because of the limited revenue that antibiotics produce, and global health officials are concerned that the lack of new antibiotics will exacerbate the rise in antimicrobial resistance (AMR). 

Going forward, the NHS will require companies that submit a tender for a contract to comply with the BSI Kitemark for Minimized Risk of AMR certification. The certification was developed by the British Standards Institute (BSI) and the AMR Industry Alliance in 2023 to confirm that antibiotic manufacturers are appropriately controlling waste streams containing antibiotics and other drug products. It was created to address concerns that the release of antibiotic residues into waterways by antibiotic manufacturers is contributing to the spread of AMR.

Promoting trust in the antibiotic supply chain

"Taking action against the growing threat from AMR and reducing waste discharge from the manufacturing process into the environment will help safeguard patients, protect antibiotic efficacy for future generations and help support the long-term fight against AMR, accelerating progress towards a sustainable world," BSI Global Director of Healthcare Sustainability Courtney Soulsby said in a BSI press release.

More than 25 antibiotic products to date have achieved certification under the program. But Melissa Mitchell, MBA, of the AMR Industry Alliance says requiring certification through the procurement process will provide an additional incentive.

"By introducing an incentive to companies to certify their responsible antibiotic manufacturing within the procurement process, the model will further support efforts to tackle AMR by reducing antibiotic discharge while promoting a greater level of trust and verification to the antibiotic supply chain," she said in an AMR Industry Alliance press release.

A study in Australia suggests the gut microbiomes of nursing home residents harbor hundreds of antibiotic resistance genes (ARGs), researchers reported yesterday in the Journal of Infection.

Conducted from March 2019 through March 2020 at five long-term aged-care facilities in South Australia, the study analyzed resident stool samples and medical records to define the gut resistome in nursing home residents and determine the relationship between antibiotic exposure and enteric ARG carriage. 

Because of the challenges of diagnosing infections in the elderly and the higher likelihood of poor outcomes, widespread empiric antibiotic use is common in nursing homes, and residents experience disproportionate rates of drug-resistant infections. But little is known about asymptomatic carriage of resistance elements.

Doxycycline associated with high ARG abundance

Of the 164 residents (median age, 88; 71.9% women) who provided stool samples, 61% were prescribed antibiotics at least once in the prior 12 months (median prescriptions, 4), primarily for soft tissue, respiratory, or suspected urinary tract infections. The most commonly prescribed antibiotics were penicillins (33.5%), cephalosporins (32.3%), trimethoprim (22%), and doxycycline (12.8%). 

Metagenomic analysis identified more than 1,100 unique ARGs conferring resistance to 38 antibiotic classes, including 20 ARGs of high clinical concern. Carriage of one or more ARGs of clinical concern was identified in 99% of participants.

Multivariate analysis found doxycycline exposure to be the greatest risk factor for high ARG abundance (adjusted odds ratio [aOR], 14.8; 95% confidence interval [CI], 5.3 to 40.9). High enteric ARG abundance was also associated with the number of separate antibiotic exposures (aOR, 6.4; 95% CI, 2.5 to 16.5), exposures within the prior 30 days (aOR, 4.6; 95% CI, 1.9 to 11.2) and prior 30 to 100 days (aOR, 2.6; 95% CI, 1.1 to 6.1), high duration of antibiotic exposure (aOR, 7.9; 95% CI, 3.1 to 19.9), and exposure to three or more antibiotic classes (aOR, 7.4; 95% CI, 2.9 to 18.6). 

"Overall, the implications of our findings extend beyond individual treatment options," the study authors wrote. "They emphasise the importance of a holistic approach to antibiotic stewardship in long-term aged care settings, particularly in light of the expected surge in long-term aged care residency in the future."

Since 2021, the US Centers for Disease Control and Prevention (CDC) has recommended dengue vaccination for kids ages 9 to 16 in communities where more than 20% of age-eligible persons have previously been infected with the virus. While vaccination offers strong protection for people with prior infections, but it may increase the risk of severe dengue and hospitalization among those without previous infection at the time of vaccination.

According to a new seroprevalence survey study in Morbidity and Mortality Weekly Report, more than 60% of school-aged children in American Samoa have evidence of a previous dengue infection, suggesting the region meets the criteria established for routine dengue vaccination. 

Schoolchildren had widespread dengue exposure 

From 2016 through 2018, a dengue outbreak in America Samoa resulted in 660 confirmed cases, and transmission of the vector-borne virus was classified as frequent or continuous. 

In the study, a total of 887 students received testing in September and October 2023. The median participant age was 11 years, and 54% of participants were girls. Among tested students, 492 (56%) received positive results for dengue immunoglobulin G, and 371 (42%) received negative results; results for 24 (3%) students were uninterpretable, the authors said. 

Estimated seroprevalence among all students aged 7 to16 years was 59% (95% confidence interval [CI], 47% to71%) and was 60% (95% CI, 48% to 72%) among those age-eligible for vaccination (9 to 16 years). 

In American Samoa, dengue vaccines could be part of a broader strategy for dengue control.

"Seroprevalence is high among all age groups, indicating widespread previous exposure to DENV and potential risk for future outbreaks as well as associated secondary cases among persons previously infected," the authors concluded. "In American Samoa, dengue vaccines could be part of a broader strategy for dengue control."