This episode of the Infectious Disease Puscast features Drs. Daniel Griffin and Sara Dong reviewing recent medical literature. Key topics in virology include the alarmingly low RSV immunization coverage (29%) among infants in the U.S. during the 2023-24 season, the non-inferiority of Biktarvy for second-line HIV therapy even with baseline resistance, and a study showing interferon-alpha nasal spray reduced COVID-19 incidence in cancer patients. The bacterial section covers a study suggesting that suppressive antibiotic therapy for recurrent UTIs may lead to more severe infections when they occur, reinforces that treating asymptomatic bacteriuria in kidney transplant patients is not beneficial, discusses rising trends and high mortality in U.S. leptospirosis cases, and highlights the potential of non-invasive tongue swabs for diagnosing TB in young children. Fungal and parasitic discussions include proposed criteria for defining "uncomplicated" candidemia to guide future trials on shorter therapy, and case reports of cutaneous acanthamoebiasis. Finally, two miscellaneous papers on the antibiotic linezolid are examined, revealing a link between high cumulative doses and optic nerve disorders, and extreme concentration variability in ICU patients, suggesting a need for therapeutic drug monitoring.
Infectious Disease Puscast #88: A Review of Recent Medical Literature
2:12 Low RSV Immunization Rates: A CDC report reveals that during the 2023-2024 season, only 29% of infants were protected against RSV through either maternal vaccination or the nirsevimab monoclonal antibody. Coverage varied significantly by state, from a low of 11% to a high of 53%, highlighting a major gap in preventing the most common cause of infant hospitalization.
5:08 HIV Treatment Simplification: An open-label trial in Haiti found that switching virally suppressed patients on complex second-line protease inhibitor regimens to a simple, once-daily Biktarvy regimen was non-inferior. This held true even in patients with significant pre-existing NRTI resistance, suggesting Biktarvy is a robust and effective option for treatment simplification.
8:33 Nasal Spray for COVID-19 Prophylaxis: In a randomized controlled trial involving cancer patients, a daily interferon-alpha nasal spray reduced the incidence of COVID-19 by 40% compared to a placebo. Interestingly, it did not show a similar effect against other common respiratory viruses.
11:21 Suppressive Antibiotics and UTI Severity: A retrospective study found that women with recurrent UTIs on long-term suppressive antibiotic therapy had a higher incidence of severe infections, including pyelonephritis and septicemia, compared to those treated episodically. This suggests that while suppressive therapy may reduce frequency, it could increase the severity of breakthrough infections.
14:41 No Benefit to Treating Asymptomatic Bacteriuria in Transplant Patients: A meta-analysis of randomized controlled trials confirms that routine screening and antibiotic treatment for asymptomatic bacteriuria in kidney transplant recipients do not reduce subsequent symptomatic UTIs or improve graft outcomes. The evidence supports avoiding treatment, particularly after the initial post-transplant period.
18:16 Alarming Trends in U.S. Leptospirosis Cases: An analysis from 2014-2020 shows that U.S. leptospirosis cases are increasing. The disease carries high rates of morbidity and mortality, with 85% of reported cases requiring hospitalization and 10% resulting in death.
20:35 Tongue Swabs for Pediatric TB Diagnosis: A study in South Africa demonstrated that tongue swabs for tuberculosis testing in children under five have a sensitivity similar to the more invasive gastric aspirate procedure. This presents a promising, less invasive diagnostic tool for a challenging patient population.
24:58 Defining "Uncomplicated" Candidemia: A review article proposes a definition for uncomplicated candidemia, including criteria like blood culture clearance within five days and effective source control. This framework aims to identify patients who could be candidates for shorter antifungal therapy in future clinical trials.
29:00T. cruzi Screening in Blood Donors: A review of military blood donors in San Antonio, an area with a high prevalence of T. cruzi in vectors, found a very low rate of reactive antibody tests (0.055%) and zero confirmed cases of Chagas disease. The findings raise questions about the clinical utility and consequences of this screening program.
34:31 Linezolid Safety and Monitoring: Two papers highlight safety concerns with the antibiotic linezolid. A pharmacovigilance analysis identified a signal for optic nerve disorders, particularly in younger patients receiving high cumulative doses. Separately, a case report from an ICU demonstrates extreme variability in drug concentrations, suggesting that therapeutic drug monitoring may be necessary in critically ill patients to ensure efficacy and avoid toxicity.
Summary of Discussed Articles (from description links):
Viral
Infants (RSV): A CDC report reveals that only 29% of infants were immunized against RSV in the 2023-2024 season, either through maternal vaccination or receiving the monoclonal antibody nirsevimab.
HIV and viral suppression: A trial in Haiti showed that switching patients from a complex protease inhibitor regimen to Biktarvy was effective and non-inferior for maintaining viral suppression, even with baseline resistance.
Nasal Spray Prophylaxis: An interferon-alpha nasal spray was found to significantly reduce the incidence of COVID-19 among cancer patients in a randomized, placebo-controlled trial.
Bacterial
Recurrent urinary tract infections: A study suggests women on suppressive antibiotic therapy for recurrent UTIs may experience more severe infections (like pyelonephritis) when breakthrough infections occur.
Asymptomatic bacteriuria: A systematic review confirms that treating asymptomatic bacteriuria in kidney transplant recipients with antibiotics does not provide a clinical benefit and is not recommended.
Leptospirosis: Analysis of U.S. data from 2014-2020 shows that leptospirosis cases are increasing, with high rates of hospitalization (85%) and death (10%).
Tongue Swabs (TB): Research indicates that tongue swabs are a viable, non-invasive alternative to gastric aspirates for diagnosing tuberculosis in children under five, offering similar performance.
Fungal
The Last of Us Season 2: A link to a teaser trailer for the upcoming season of the HBO show.
Candidaemia: This review proposes a set of criteria to define "uncomplicated" candidemia in adults, aiming to identify patients who may be eligible for shorter courses of antifungal therapy in future studies.
Parasitic
Trypanosoma cruzi Antibody Screening: A study of military blood donors in San Antonio found that despite a high prevalence of the vector, reactive antibody screens were rare and there were no confirmed cases of Chagas disease.
Cutaneous acanthamoebiasis: Two case reports highlight the diverse pathological findings of this rare skin infection in immunocompromised patients, emphasizing the need for high clinical suspicion.
Miscellaneous
Pharmacovigilance Analysis (Linezolid): An analysis of FDA data identified a safety signal linking linezolid use to optic nerve disorders, particularly with high cumulative doses.
Linezolid concentrations: A case report from an ICU demonstrates extreme and unpredictable variability in linezolid blood concentrations, arguing for the use of routine therapeutic drug monitoring in critically ill patients.