Evaluation of the timing of MRSA PCR nasal screening: How long can a negative assay be used to rule out MRSA-positive respiratory cultures?

PURPOSE: Previous studies indicate that the polymerase chain reaction (PCR) nasal assay for methicillin-resistant Staphylococcus aureus (MRSA) has a consistently high (>95%) negative predictive value (NPV) in ruling out MRSA pneumonia; however, optimal timing of PCR assay specimen and respiratory culture collection is unclear. METHODS: A study including 736 patients from a community hospital system was conducted. Patients were included if they had undergone MRSA nasal screening with a PCR assay and had documented positive respiratory culture results. RESULTS: In the full cohort, the MRSA PCR nasal screen assay was demonstrated to have an NPV of 94.9% (95% confidence interval [CI], 92.8%-96.5%) in ruling out MRSA-positive respiratory cultures. When evaluating the NPV by level of care (ie, where the MRSA PCR nasal assay sample was collected), no significant difference between values for samples collected in an intensive care unit vs medical/surgical units was identified (NPV [95%CI], 94.9% [92.7%-96.6%] vs 95.3% [88.4%-98.7%]). Additionally, NPV remained high with use of both invasive (NPV [95%CI], 96.8% [92.7%-99.0%]) and noninvasive (NPV [95%CI], 94.5% [91.7%-96.2%]) respiratory sampling methods. Finally, when evaluating the effect of time between MRSA PCR nasal screening and respiratory sample collection, we found high NPVs for all evaluated timeframes: within 24 hours, 93.8% (90.1%-96.4%); within 25 to 48 hours, 98.6% (92.7%-100.0%); within 49 hours to 7 days, 95.7% (91.4%-98.3%); within 8 to 14 days, 92.9% (85.1%-97.3%); and after more than 14 days, 95.5% (84.5%-99.4%). CONCLUSION: We report high NPVs for up to 2 weeks between specimen collections, which allows clinicians to use a negative MRSA PCR nasal screen assay to rule out MRSA pneumonia, potentially leading to decreased exposure to MRSA-active antibiotics.

Multiple Health Benefits and Minimal Risks Associated with Vegetarian Diets.

PURPOSE OF REVIEW: Understand the current prevalence, health benefits, and health risks of vegetarian diets. RECENT FINDINGS: Since the publishing of the Adventist Health Study 2 in 2013, there have been several prospective diet studies demonstrating and challenging the health benefits and risks of the vegetarian diet. The definition of the vegetarian diet has become more specific over time and requires standardization for research purposes. Despite an uptrend in sales rates of plant-based foods per year, a 2018 Gallup poll showed overall stagnation of the percentage of self-reported vegetarians and vegans compared to percentages obtained 6 years prior. Compared to the Adventist Health Study, more recent vegetarian diet studies have demonstrated significant although smaller risk reductions for mortality in cardiovascular disease, cerebrovascular disease, diabetes mellitus, and chronic kidney disease. Recent studies have correlated certain food groups with early death or increased longevity. In addition, the vegetarian health risks of deficiencies of protein, omega-3 fatty acids, vitamin D, vitamin B12, iron, calcium, and zinc are explored.

Practices Involved in the Enteral Delivery of Drugs.

PURPOSE OF REVIEW: While the delivery of medications through enteral tubes is common in critically ill patients, there are complications and a lack of unified practices between institutions. The purpose of this review is to evaluate current practices and literature evidence regarding this administration route. The effect of this administration on the medication's efficacy, safety, tolerability, and pharmacokinetics was examined, as well as other considerations to ensure that this route of delivery is both safe and effective for patients. RECENT FINDINGS: Studies have found crushed oral tablets are the most frequent cause of obstructed feeding tubes. Complications such as this are primarily due to inadequate personnel training and failure to properly access medications before enteral administration. There are many factors that should be considered in order to effectively administer drugs via enteral tubes. Formal training and use of a multi-disciplinary approach that includes pharmacists and dieticians has been shown to reduce tube obstructions and administration errors.