This podcast reviews recent infectious disease literature from early August 2018, focusing on viral epidemiology, antimicrobial resistance, and critiques of clinical studies. Key topics include the prevalence of CMV shedding (particularly in youth), the characterization of a novel alpha virus (Madariaga Virus, MADV), and the mechanism of the new anti-HIV monoclonal antibody Ibalisumab. The discussion is heavily critical of poor study methodology and clinical dogma, notably rejecting the purported benefit of high-dose Amoxicillin/clavulanate for sinusitis and arguing against the use of prophylactic antibiotics for acute aspiration pneumonitis, as this only drives resistance without clinical gain. Furthermore, the speaker suggests that Vancomycin is increasingly obsolete, especially for MRSA pneumonia, and highlights the immediate resistance risks associated with the new gonorrhea drug, Gepotidacin. The review also touches on non-actionable findings in the human microbiome and the increasing endemicity of parasites (Leishmaniasis, Rat Lungworm) and climate-related pathogens (Vibrio) in non-traditional geographic areas.
Infectious Disease Literature Review (August 2018)
0:39 CMV Shedding Prevalence: A study examining CMV in the urine of 6,800+ people found an overall prevalence of 3.8%. Shedding is significantly higher in younger populations (~10% rate). This provides context for CMV transmission epidemiology.
1:27 Madariaga Virus (MADV): This alpha virus is confirmed as genetically distinct from Eastern Equine Encephalitis Virus (EEEV) and Venezuelan Equine Encephalitis Virus (VEEV). MADV, found in South America, rarely causes encephalitis in humans but is problematic in horses. Spread is via mosquitoes, with potential bat/rodent reservoirs.
3:17 HIV Management Shift: HIV patients face long-term cardiovascular risks due to an atherogenic phenotype associated with abdominal obesity, hypertension, and dyslipidemia. As far as I can tell, managing these comorbidities is boring, but essential for long-term survival.
4:11 Ibalisumab (HIV Monoclonal Antibody): This new drug is mechanically interesting: it binds CD4 extracellular domain 2, preventing necessary conformational changes for viral entry. Phase 3 trials showed significant antiviral activity in advanced disease, but resistance is, predictably, inevitable.
5:26 Non-Mumps Parotitis: Studies suggest that Influenza (especially A) and HSV may cause parotitis. Skeptical consideration (using Hill’s criteria) confirms this association strongly suggests influenza-induced parotitis is a syndrome.
6:42 Scrub Typhus Alternative Treatment: In a Korean study comparing Doxycycline and Rifampin (rafampen) for Orientia tsutsugamushi (Scrub Typhus), the outcomes and side effects were equivalent. Rifampin is a valid backup if Doxycycline resistance (seen in Thailand) is a concern.
7:26 Lyme Prophylaxis & Tick Engorgement: Prophylactic Doxycycline is typically given only if tick feeding exceeded 36 hours. The "scutum index" (body length/scutum width) is proposed to quantify engorgement time. The study implies 40% of prophylaxis may be unnecessary, but annoyingly, the critical 36-hour scutum index cutoff is not provided.
10:08 Leptospirosis in Dogs: A study from Algiers found 4.8% of dog urine was PCR positive for Leptospirosis. This is a reminder that domestic dogs are significant vectors worldwide, posing risks to owners, especially in high-rainfall US regions.
11:12 Gepotidacin for Gonorrhea: This novel bacterial type 2 topoisomerase inhibitor cured >95% of patients in a Phase 2 study with a single oral dose. However, two of three treatment failures already exhibited high-level resistance. I estimate this drug's clinical usefulness will be extremely limited due to rapid resistance emergence.
12:19 Rejection of Sinusitis Study Premise: The study comparing high-dose vs. standard-dose Amox/Clav for sinusitis claimed rapid improvement with the high dose. I reject this premise; the data showed no statistical difference in outcomes (SNOT scores or 10-day resolution), but high dose caused more severe diarrhea. Furthermore, the funding mechanism (corresponding author self-funded) is non-transparent and concerning for a supposedly positive study.
14:49 C. difficile Modifiable Risk: Recurrent C. difficile mortality predictors include a modifiable risk factor: PPI use. There is strong evidence supporting the discontinuation of PPIs in patients with C. diff infection.
15:22 Microbiome Studies (Interesting but Non-Actionable): Three studies linked gut microbiome alterations to various outcomes (neutropenic episodes, childhood mortality, cholera susceptibility). As far as I can tell, this information is currently non-actionable for individual patient care, although mechanistically interesting.
16:56 Prosthetic Joint Infections (PJI): Outcomes confirm standard protocol: long-duration treatment and inclusion of Rifampin are critical for success, regardless of the initial timing of the infection (early or late). Smoking remains a key risk factor for failure.
17:27 Aspiration Prophylaxis Rejection: A retrospective study confirmed that prophylactic antibiotics for acute aspiration pneumonitis offer no clinical benefit. Instead, they generate selective pressures resulting in the need for escalation if pneumonia subsequently develops. The premise that acute aspiration requires anti-anaerobic coverage (a common clinical error) is definitively unsupported.
19:21 Vancomycin Obsolescence: A retrospective Japanese study on MRSA treatment outcomes showed Vancomycin was associated with the lowest survival rates, particularly in pneumonia (p=0.034). This confirms my bias: Vancomycin should be relegated to the dustbin of history.
20:29 Climate Change and Vibrio: Warming ocean waters (e.g., Norway, Pacific Northwest) facilitate Vibrio replication, increasing outbreaks associated with raw oyster consumption. This is a predictable, global consequence of climate change.
21:35 Endemic Parasites in the US: Both Chagas disease and local, non-travel-associated leishmaniasis (L. mexicana) are endemic, particularly in Texas.
22:06 Rat Lungworm (Angiostrongylus cantonensis): This pathogen, causing eosinophilic meningitis, has been linked to cases in the US. The primary risk is consuming raw vegetables contaminated with snail/slug feces, or consuming raw snails.