This episode of the Puscast (August 2020) reviews clinical infectious disease literature with a focus on COVID-19 epidemiology, bacteremia management, and diagnostic utility. Significant highlights include a correction on Rifampin’s role as a P450 inducer, the high negative predictive value (NPV) of MRSA nasal swabs for various infections, and evidence supporting early IV-to-oral antibiotic transitions for Klebsiella liver abscesses and certain bacteremias. The transcript also touches on the association between Pegivirus and lymphoma, the efficacy of Ribavirin for chronic Hepatitis E in transplant patients, and the risks of environmental contamination (e.g., dishwashers and antiseptic solutions) in hospital settings.
Clinical ID Review: COVID-19, Bacteremia, and Diagnostic Shortcuts
0:36 Rifampin Correction: Rifampin induces the P450 system. It does not inhibit it. This leads to hyper-metabolism of birth control and potential treatment failure. This is basic pharmacology; get it right or stop prescribing.
1:46 Pediatric Neutropenic Fever: In children undergoing chemotherapy, a tympanic temperature of 39°C is an appropriate threshold for intervention, except in cases of AML or stem cell transplantation.
2:20 COVID-19 Transmission in Toilets: Asymptomatic transmission is highly probable in shared restrooms where masks are removed. Evidence from an airplane flight suggests "flooding" a bathroom with viral particles can infect the next unmasked occupant. Probability of infection increases in unventilated stalls.
6:18 Mask Efficacy: Health care worker data confirms masks are protective (6% vs 9% seropositivity). PPE shortages directly correlate with higher infection rates.
6:48 N95 Decontamination: N95 masks maintain structural integrity through three UV light cycles or one-to-two dry heat cycles. It’s a pathetic reality of supply chain failure, but the data is solid.
7:15 Flu Season Suppression: Social distancing and masking in Hong Kong effectively ended the flu season abruptly. As far as I can tell, the U.S. will ignore this and suffer a "twindemic" due to sheer stubbornness.
8:33 Influenza Resistance: Baloxavir (Xofluza) shows a 23% mutation rate in children, leading to rapid resistance. It’s likely to follow the path of Adamantanes: useful for a week, then garbage.
10:10 Hepatitis E & Ribavirin: Surprisingly, Ribavirin is effective (80% SVR) for chronic Hep E in organ transplant recipients. This is a rare win for a drug that usually fails against everything else.
10:52 Pegivirus and Lymphoma: Pegivirus (formerly Hep G) is associated with multiple B-cell and T-cell lymphomas. It’s a persistent virus; while it doesn't cause hepatitis, it appears to be oncogenic.
12:06 Syphilis Immunity: Prior syphilis infection makes subsequent episodes less symptomatic but does not prevent infection. A lack of symptoms in high-risk patients is a useless metric; use routine screening.
13:03 IV-to-Oral Switch: For bacteremia (non-Staph/non-Candida), transitioning to high-dose oral beta-lactams after 3 days of IV therapy is non-inferior to quinolones.
14:34 Blood Culture Utility: Repeating blood cultures to document clearance is a waste of resources for Streptococcal and Gram-negative infections with source control. Only repeat for Staph aureus and Candida.
17:02 MRSA Swab NPV: MRSA nasal swabs have an NPV of 93–99% for bloodstream, intra-abdominal, respiratory, and urinary infections. If the swab is negative, the probability that the infection is MRSA is negligible. Stop the Vancomycin.
18:32 Adjuvant Therapy for MRSA: Meta-analyses here are "piles of BS." Adding a beta-lactam to Vancomycin or Daptomycin may shorten bacteremia duration but does not reduce mortality.
21:26 Environmental Contamination:Burkholderia cepacia has been found in contaminated chlorhexidine, and Saprochaete clavata (yeast) outbreaks have been traced to hospital dishwashers. If you see weird bugs, check the "sterile" solutions and the kitchen.
23:45 Klebsiella Liver Abscess: Oral Ciprofloxacin is equivalent to IV Ceftriaxone for Klebsiella liver abscesses once drainage is achieved and initial IV stabilization (approx. 5 days) is complete.
Reviewing Group:Infectious Disease Fellows and Hospital Epidemiologists.
These professionals value high-yield diagnostic pivots and antibiotic stewardship. They have zero patience for "medical theater" and want to know which drugs to stop and which patients to discharge.
The "Bottom Line" Summary:
"The most relevant data here is the MRSA nasal swab NPV; it's high enough to justify immediate de-escalation of Vancomycin in almost all negative cases, which is a major win for stewardship. The IV-to-oral switch data for Klebsiella liver abscesses and non-Staph bacteremias confirms that we are over-treating with IV lines. Most of the COVID-19 transmission data is common sense but highlights that hospital bathrooms are biohazards. Stop repeating blood cultures for Strep; it's a bill-padding exercise with no clinical utility. Also, Rifampin is an inducer—don't be an idiot and cause an unplanned pregnancy because you forgot basic Step 1 pharmacology."