Treatment of Acinetobacter Infections in Elderly Patients with Asthma

First-line Treatment Options

For Acinetobacter species that is not responding to piperacillin/tazobactam, treatment should be guided by antimicrobial susceptibility testing results, as recommended by the Infectious Diseases Society of America 1, 2
If the Acinetobacter isolate is susceptible to carbapenems, treatment with either a carbapenem (imipenem 500 mg IV q6h or meropenem 1 g IV q8h) or ampicillin/sulbactam (3 g IV q6h) is recommended, according to the Clinical Infectious Diseases guidelines 1, 3

If the Acinetobacter is sensitive only to polymyxins, intravenous polymyxin (colistin) is strongly recommended, with a dosing regimen of 5 mg/kg IV as a loading dose, then 2.5 mg (1.5 CrCl + 30) IV q12h, as suggested by the Journal of Microbiology, Immunology and Infection 1, 2, 3
Adjunctive inhaled colistin should be added to improve clinical outcomes, with a daily dose of 1.25-15 MIU divided in q8-12h, each dose diluted in 5 mL sterile normal saline, as recommended by the Clinical Infectious Diseases and Journal of Microbiology, Immunology and Infection guidelines 1, 3

If susceptibility testing shows sensitivity to aminoglycosides, consider gentamicin (5-7 mg/kg IV qd) or amikacin (15-20 mg/kg IV qd), but be cautious with aminoglycosides in elderly patients due to risk of nephrotoxicity, as warned by the American Journal of Respiratory and Critical Care Medicine and Journal of Microbiology, Immunology and Infection 3, 4
Tigecycline is not recommended for Acinetobacter infections due to increased mortality compared to other agents, as stated by the Journal of Microbiology, Immunology and Infection and Clinical Infectious Diseases guidelines 1, 3

For respiratory infections like pneumonia, a 14-day course of antibiotics is standard for Acinetobacter infections, as recommended by the Thorax journal 5
Monitor renal function closely, especially in elderly patients receiving nephrotoxic agents like colistin, as suggested by the Clinical Infectious Diseases guidelines 1
Consider obtaining follow-up sputum cultures to document clearance of infection, as recommended by the European Respiratory Journal 6

Be vigilant for potential drug interactions and adverse effects, particularly in elderly patients with multiple comorbidities, as warned by the Clinical Infectious Diseases guidelines 1
Colistin therapy has shown clinical cure in 57% of patients with Acinetobacter VAP with acceptable toxicity, as reported by the American Journal of Respiratory and Critical Care Medicine 4

Avoid aminoglycoside monotherapy for Acinetobacter infections as it is not recommended due to poor outcomes, as stated by the Clinical Infectious Diseases guidelines 1, 2
Do not use third-generation cephalosporins as they typically have poor activity against Acinetobacter species, as warned by the American Journal of Respiratory and Critical Care Medicine 4
Avoid tigecycline due to increased mortality risk and FDA boxed warning, as stated by the Journal of Microbiology, Immunology and Infection and Clinical Infectious Diseases guidelines 1, 3