Infectious Meningitis and Encephalitis.

Infectious meningitis and encephalitis are associated with significant morbidity and mortality worldwide. Acute bacterial meningitis is rapidly fatal and early recognition and institution of therapy are imperative. Viral meningitis is typically a benign self-limited illness. Chronic meningitis (defined as presenting with >4 weeks of symptoms) is most often caused by tuberculosis and fungal infection. Because the diagnostic testing for tuberculous meningitis is insensitive and cultures often take weeks to grow, therapy is often initiated empirically when the diagnosis is suspected. Human simplex virus encephalitis is the most common cause of encephalitis and requires prompt treatment with intravenous acyclovir.

Cellulitis.

Cellulitis is a common infection of the skin and subcutaneous tissue caused predominantly by gram-positive organisms. Risk factors include prior episodes of cellulitis, cutaneous lesions, tinea pedis, and chronic edema. Cellulitis is a clinical diagnosis and presents with localized skin erythema, edema, warmth, and tenderness. Uncomplicated cellulitis can be managed in the outpatient setting with oral antibiotics. Imaging often is not required but can be helpful. Recurrent cellulitis is common and predisposing conditions should be assessed for and treated at the time of initial diagnosis. For patients with frequent recurrences despite management of underlying conditions, antimicrobial prophylaxis can be effective.

Machine learning for the prediction of antimicrobial stewardship intervention in hospitalized patients receiving broad-spectrum agents.

OBJECTIVE: A significant proportion of inpatient antimicrobial prescriptions are inappropriate. Post-prescription review with feedback has been shown to be an effective means of reducing inappropriate antimicrobial use. However, implementation is resource intensive. Our aim was to evaluate the performance of traditional statistical models and machine-learning models designed to predict which patients receiving broad-spectrum antibiotics require a stewardship intervention. METHODS: We performed a single-center retrospective cohort study of inpatients who received an antimicrobial tracked by the antimicrobial stewardship program. Data were extracted from the electronic medical record and were used to develop logistic regression and boosted-tree models to predict whether antibiotic therapy required stewardship intervention on any given day as compared to the criterion standard of note left by the antimicrobial stewardship team in the patient's chart. We measured the performance of these models using area under the receiver operating characteristic curves (AUROC), and we evaluated it using a hold-out validation cohort. RESULTS: Both the logistic regression and boosted-tree models demonstrated fair discriminatory power with AUROCs of 0.73 (95% confidence interval [CI], 0.69-0.77) and 0.75 (95% CI, 0.72-0.79), respectively (P = .07). Both models demonstrated good calibration. The number of patients that would need to be reviewed to identify 1 patient who required stewardship intervention was high for both models (41.7-45.5 for models tuned to a sensitivity of 85%). CONCLUSIONS: Complex models can be developed to predict which patients require a stewardship intervention. However, further work is required to develop models with adequate discriminatory power to be applicable to real-world antimicrobial stewardship practice.