As an expert in Clinical Microbiology and Infectious Disease Epidemiology, I will adopt the necessary analytical framework to synthesize this literature review.
Abstract:
This presentation functions as a bi-weekly literature review covering key developments in infectious disease and antimicrobial resistance observed during the first two weeks of December 2014, delivered from an established clinical perspective.
The review immediately addresses the escalating crisis of multi-drug-resistant organisms (MDROs), highlighting the projection that drug-resistant bacteria could cause 10 million annual deaths by 2050, suggesting this threat is more pressing than concerns over sporadic outbreaks like Ebola. Regarding HIV evolution, the presentation contrasts findings: in the US, HIV appears to be becoming more virulent in the context of reduced transmission opportunities, whereas in Botswana, selection pressure related to the protective HLA-B*57 genotype has driven the local viral population toward lower replicative capacity. Vector-borne disease risks are noted, specifically the establishment of locally transmitted Chikungunya virus in South Florida, raising concern for future spread in the Southern US.
Serological testing is critically reviewed: acute hepatitis of various etiologies can induce false-positive antibody results across multiple panels (e.g., HIV, RPR), necessitating concurrent testing for Hepatitis E, which is noted as an under-recognized cause of non-A/B/C hepatitis in immunocompetent individuals. In influenza management, the ineffectiveness of IV peramivir in hospitalized patients is highlighted, reinforcing vaccination as the primary defense, despite its imperfect efficacy (especially in the elderly). Furthermore, data suggests that patient acceptance of reality regarding vaccines and infectious etiquette (coughing) remains poor. Studies on Lyme serology testing indicate that specialized labs often employ criteria that dramatically decrease specificity, leading to high false-positive rates in low-pre-test-probability populations. Finally, common nosocomial risks are examined, including the prevalence of MRSA on public buses, contamination of sinks/water sources with Gram-negative rods like Pseudomonas, and a critique of using the imprecise term "aspiration pneumonia."
Suggested Reviewer Cohort:
This material is most relevant to Infectious Disease Clinicians, Public Health Officials, and Clinical Microbiologists involved in infection control, epidemiology, and antimicrobial stewardship.
Summary of Literature Review (December 2014 Coverage)
00:00:23 Escalation of Antimicrobial Resistance (AMR): The speaker views the rise of MDROs (e.g., MRSA, VR) as a critical, realistic threat, projecting 10 million annual deaths globally by 2050, asserting this is a greater issue than immediate crises like Ebola.
00:01:37 Divergent HIV Virulence: Data suggests HIV in the US is evolving toward greater virulence due to selection pressure favoring high replicative rates, contrasting with Botswana where viral evolution is driven by selection against the protective HLA-B*57 status, resulting in less aggressive local strains.
00:03:09 Chikungunya Establishment: Local transmission of Chikungunya virus has been confirmed in South Florida (Miami Dade, Palm Beach, St. Lucie, Broward Counties), suggesting a significant vector-borne risk for the Southern US due to mosquito ubiquity.
00:04:20 Serology Cross-Reactivity Concerns: Acute viral hepatitis (various types) frequently causes false-positive serology results for other infectious agents (including HIV, HDLV, RPR). Hepatitis E should be added to standard acute hepatitis panels, as it is an underrecognized cause of liver disease in non-travelers in Western Europe.
00:06:05 Influenza Vaccine Efficacy & Treatment Failure: The current trivalent flu vaccine efficacy is low (~60% overall, ~39% in the elderly) against circulating H3 strains. IV peramivir showed no benefit in treating hospitalized influenza patients, re-emphasizing vaccination as the best prevention modality.
00:08:25 Public Health Compliance Gaps: Despite accurate data presentation, public misconception persists (e.g., 40% believe the flu vaccine causes flu). Furthermore, college students exhibit poor respiratory hygiene, often coughing/sneezing into hands.
00:09:39 HPV Vaccine Safety Confirmed: A study of 128,000 girls indicated that receiving the HPV vaccine does not correlate with increased risky sexual behavior or higher STD/pregnancy rates.
00:10:26 Lyme Disease Testing Specificity Issues: Comparing standard labs to specialized Lyme labs found that while standard two-step testing was equivalent, the interpretation methods used by Lyme labs (to increase sensitivity) resulted in significant loss of specificity, with high false-positive rates among healthy controls (up to 57.5% meeting IGM or IGG criteria).
00:11:31 Importance of Pre-Test Probability: An editorial point emphasizes that serology does not diagnose disease; low pre-test probability leads to a higher likelihood of false positives, particularly in routine Lyme screening.
00:12:02 Environmental Contamination and Transmission: Studies culturing hospital door knobs and public buses confirmed the prevalence of pathogens; 63% of Staphylococcus isolates from bus samples carried MRSA genes (both community-acquired and hospital-acquired types), underscoring the need for diligent hand hygiene.
00:13:39C. difficile Therapy Observation: A small case series suggested 80% cure rates for severe C. difficile using a triple therapy (metronidazole, vancomycin, IV tigecycline), although the low N size limits definitive conclusions.
00:14:43 Vitamin D Deficiency Association: A correlation was noted between Vitamin D deficiency and community-acquired C. difficile infection, noting Vitamin D's role as an immune co-factor.
00:15:16 Healthcare Sink Contamination: Outbreaks of Pseudomonas infections were linked to contaminated sink drains in ICUs, reinforcing the concept that water sources near patients can harbor Gram-negative organisms.
00:16:04 Critique of "Aspiration Pneumonia" Terminology: The speaker criticizes the sloppy use of "aspiration pneumonia," arguing that while all bacterial pneumonia involves aspiration, the term should be reserved for specific anaerobic lung abscesses resulting from gross aspiration events, as non-specific use obscures etiology.
00:17:49 Prophylactic Antibiotics for Endocarditis: Data from England suggested that reducing prophylactic antibiotic prescriptions following new guidelines correlated with an increase in endocarditis rates, suggesting a potential benefit to prophylaxis that warrants further study.
00:19:37 Antibiotic Dosing Strategy: To mitigate resistance development, the speaker advocates for maximal antibiotic dosing for the shortest effective duration, expressing concern that thrice-weekly anti-tubercular therapy allows for sub-therapeutic levels and subsequent acquisition of resistance (as seen with rifampin resistance in HIV patients).
00:21:06 Antifungal Equivalence: A meta-analysis found equivalent efficacy between azoles (e.g., fluconazole, voriconazole) and echinocandins (e.g., caspofungin) for Candida infection treatment/prophylaxis, though the drug heterogeneity made the conclusion inherently questionable.
00:22:20 Fungal Biomarker Caveats: The clinical utility of fungal blood tests (1,3-$\beta$-D-glucan and galactomannan) is limited by high false-positive rates when ordered in low-prevalence settings (e.g., asymptomatic patients on prophylaxis), reinforcing the necessity of ordering tests congruent with the clinical syndrome.
00:23:51Leishmania Global Spread: Genetic analysis shows that Leishmania migrated to the New World via Bering Strait crossings, and subsequent Old World strains were introduced via trade routes.
00:25:18 Wild Animal Parasites: A case of human trichinellosis was traced to the consumption of wild boar meat from an Iowa game farm, illustrating that hunting wild game carries risks of zoonotic parasites.