›QT prolongation risk review required
›Good oral bioavailability for step-down
›Hospital-acquired or MDR risk regimens
›Piperacillin-tazobactam IV
›4.5 g IV every 6 hours
›Extended infusion over 4 hours per institutional protocol
›Covers Enterobacteriaceae, Pseudomonas, and anaerobes
›Meropenem IV
›1 g IV every 8 hours
›For severe MDR risk or failed first-line therapy
›Cefepime IV plus metronidazole
›Cefepime 2 g IV every 8 hours
›Metronidazole 500 mg IV every 8 hours
›For Pseudomonas coverage with additional anaerobic cover
›MRSA coverage indications
›Prior MRSA colonization or infection
›Vancomycin IV 15-20 mg/kg every 8-12 hours
›AUC-guided monitoring, target AUC/MIC 400-600
›Recent influenza or post-viral bacterial pneumonia
›Linezolid IV or PO 600 mg every 12 hours
›Platelet monitoring with prolonged use
Antibiotic guidance and pitfalls
›Metronidazole avoidance as monotherapy
›Failed in 5 of 11 cases in one randomized trial
›Inferior to clindamycin as sole agent for lung abscess
›May be used as combination partner for Gram-positive aerobic coverage
›Avoid clindamycin monotherapy for hospital-acquired or MDR-risk organisms
›Insufficient Gram-negative coverage
›Combine with Gram-negative active agent
›Step-down criteria
›Afebrile for >= 48 hours
›Clinically improving with decreasing CRP and leukocytosis
›Tolerating oral intake
›Oral options
›Amoxicillin-clavulanate PO
›875 mg/125 mg PO every 12 hours
›Alternative 500 mg/125 mg PO every 8 hours
›Preferred step-down for community-acquired anaerobic abscess
›Clindamycin PO
›300-450 mg PO every 6 hours
›C. difficile risk counseling and monitoring
›For beta-lactam allergy or severe periodontal anaerobic source
›Moxifloxacin PO
›400 mg PO daily
›Good option for atypical coverage and bioavailability
›Prolonged therapy essential
›Median treatment duration 38 days (IQR 30-51 days) in large cohort
›Typically 4-6 weeks minimum
›Continue until radiographic resolution or small stable residual cavity
›Clinical improvement precedes radiographic resolution by weeks
›Response monitoring
›Clinical improvement expected within 7-10 days of appropriate antibiotics
›CRP and leukocyte trend at 48-72 hours
›CT reassessment at 7-10 days if no clinical improvement
›Failure to improve mandates reassessment for obstruction, resistant organism, or drainage need
Drainage and interventional therapy
›Indications for drainage beyond antibiotics
›Antibiotic failure at 7-10 days
›Abscess > 5-6 cm (lower response to antibiotics alone)
›Underlying obstruction after bronchoscopic clearance
›Over 80% of lung abscesses resolve with antibiotics alone
›Percutaneous catheter drainage
›For peripheral abscesses failing medical therapy
›83% complete resolution rate
›Complication rate 16%: bleeding, empyema, bronchopleural fistula
›CT-guided placement required
›Endoscopic catheter drainage
›For central abscesses or patients with coagulopathy
›Lower complication rate than percutaneous approach
›Similar success rate to percutaneous drainage
›Surgical resection
›Reserved for massive hemoptysis, suspected malignancy, bronchopleural fistula, or failure of all other measures
›Lobectomy or segmentectomy as appropriate
›Required in approximately 13% of ICU-level lung abscess cases
›Postural drainage
›Abscess-side dependent position to facilitate drainage
›Chest physiotherapy to augment secretion clearance
›Nutritional support
›Critical given catabolic state from prolonged infection
›Correct hypoalbuminemia to reduce empyema risk
›Dietitian involvement for prolonged hospitalizations
›Swallow evaluation
›Speech language pathology for dysphagia assessment
›Modified diet or texture to prevent recurrent aspiration
›Dental evaluation
›Periodontal disease treatment to remove anaerobic inoculum source
›Delay dental procedures until infection controlled