Evaluation of Guideline Recommendations for Dual Antipseudomonal Therapy in Hospitalized Adults with Pneumonia Using Combination Antibiograms.

BACKGROUND: Guidelines for pneumonia recommend empiric dual antipseudomonal therapy in patients with specific risk factors. However, there is lack of consensus on when to use dual antipseudomonal therapy as the recommendations are rated as weak, based on low-quality evidence. OBJECTIVES: The objectives of this study were to develop combination antibiograms to assess the susceptibility of Pseudomonas aeruginosa (P. aeruginosa) in respiratory cultures to combinations of empiric antibiotics and to use combination antibiograms to delineate the impact of specific risk factors for which guidelines recommend dual antipseudomonal therapy. METHODS: A retrospective cohort study was conducted of adults hospitalized with pneumonia with positive respiratory cultures for P. aeruginosa between September 2014 and September 2018. Data collected included demographics, antimicrobial susceptibility results, and risk factors for which guidelines recommend dual antipseudomonal therapy. Combination antibiograms were developed and logistic regression was performed to identify risk factors for nonsusceptibility to beta-lactams. RESULTS: Eight hundred nineteen patients were included and 72% received antibiotics. Beta-lactam susceptibility ranged from 58% to 69% and addition of a fluoroquinolone or aminoglycoside resulted in statistically significant increases in susceptibility. However, only addition of tobramycin or amikacin provided susceptibility rates approaching or exceeding 90% stratified by pneumonia type and risk factors. Presence of guideline-based risk factors generally resulted in reduced susceptibility rates. Logistic regression identified three risk factors associated with nonsusceptibility to beta-lactams: intravenous antibiotics in the previous 90 days, nursing home residence, and mechanical ventilation at onset. The cumulative presence of each additional risk factor affected beta-lactam susceptibility rates, which were 93% in the absence of any risk factors and 39% when all three risk factors co-existed. CONCLUSIONS: Risk factors necessitating dual antipseudomonal therapy for pneumonia should be locally validated. When dual antipseudomonal therapy is indicated, tobramycin or amikacin have the best likelihood of providing adequate in vitro activity.

Outpatient treatment of osteomyelitis with telavancin.

Telavancin is a lipoglycopeptide antibiotic with bactericidal activity against Gram-positive pathogens including Staphylococcus aureus, the most frequent cause of osteomyelitis. Treatment is often challenging due to needs for surgical intervention along with prolonged administration of intravenous antimicrobials, frequently in an outpatient setting. This was a retrospective analysis of the efficacy and safety of telavancin for treatment of osteomyelitis provided as outpatient parenteral antimicrobial therapy (OPAT) in physician office infusion centres. Medical records of 60 patients receiving telavancin for osteomyelitis in 22 physician office infusion centres from 2010 to 2011 and 2013 to 2015 were reviewed. Of these, 60% were treated without hospitalisation, 37% had orthopaedic hardware and 56% had concurrent infections. Staphylococcus aureus was the most common pathogen (78%), primarily methicillin-resistant. The median duration of telavancin treatment in the outpatient setting was 21 days (range 3-105 days). Telavancin was used as first-line therapy in 32% of cases, following prior antibiotic failure in 47% and due to intolerance to previous agents in 22%, predominantly daptomycin or vancomycin. The telavancin dose was 10 mg/kg/day, adjusted for renal function in 25% of patients. The majority of patients self-administered telavancin at home via an elastomeric infusion pump. Overall clinical success was 73%. No significant differences in outcomes were observed with the presence of hardware, concurrent infection, concomitant therapies or type of osteomyelitis. Telavancin-associated adverse events occurred in 57%, with discontinuation in three patients (5%). These data demonstrate the effective and safe OPAT use of telavancin, providing an alternative for successful treatment of patients with osteomyelitis.