From the Guidelines
The recommended treatment for Pseudomonas aeruginosa infections is based on the severity of the infection, the site of infection, and the antibiotic susceptibility patterns, with options including antipseudomonal beta-lactams, aminoglycosides, and fluoroquinolones, as outlined in the most recent guidelines 1.
Treatment Options
For serious infections, combination therapy is often initiated with an antipseudomonal beta-lactam (such as piperacillin-tazobactam 4.5g IV every 6 hours, ceftazidime 2g IV every 8 hours, or meropenem 1g IV every 8 hours) plus an aminoglycoside (like tobramycin 5-7mg/kg IV daily) or a fluoroquinolone (such as ciprofloxacin 400mg IV every 8-12 hours) 1. Some key points to consider in the treatment of Pseudomonas aeruginosa infections include:
- The use of antipseudomonal penicillins or cephalosporins combined with aminoglycosides may be considered when the antimicrobial susceptibility testing results are interpreted as susceptible 1.
- Aminoglycoside monotherapy is only indicated for urinary tract infections 1.
- The suggested treatment duration is 5-10 days for complicated urinary tract infection and complicated intra-abdominal infection, and 10-14 days for hospital-acquired or ventilator-associated pneumonia and bloodstream infection 1.
- Definitive treatment durations should be individualized according to infection sites, source control, the underlying comorbidities, and the initial response to therapy 1.
Considerations
It is essential to note that Pseudomonas aeruginosa is intrinsically resistant to many antibiotics due to its impermeable outer membrane, efflux pumps, and ability to produce beta-lactamases, making appropriate antibiotic selection crucial 1. Local antibiograms should guide therapy as resistance patterns vary geographically 1. Source control through drainage of abscesses or removal of infected devices is essential when applicable 1. Dosing adjustments are necessary for patients with renal impairment 1. The choice of an antibiotic for definitive therapy should be based upon the results of antimicrobial susceptibility testing 1. In the case of carbapenem-resistant Pseudomonas aeruginosa (CRPA) or difficult-to-treat P. aeruginosa (DTR-PA), specific treatment options are recommended, including piperacillin-tazobactam, ceftazidime, cefepime, and colistin monotherapy or combination therapy 1.
From the FDA Drug Label
Pseudomonas aeruginosa should be treated in combination with an aminoglycoside Initial presumptive treatment of adult patients with nosocomial pneumonia should start with piperacillin and tazobactam for injection at a dosage of 4. 5 grams every six hours plus an aminoglycoside Treatment with the aminoglycoside should be continued in patients from whom P. aeruginosa is isolated Bone and Joint Infections caused by Pseudomonas aeruginosa Complicated Intra-Abdominal Infections (used in combination with metronidazole) caused by Pseudomonas aeruginosa Skin and Skin Structure Infections caused by Pseudomonas aeruginosa
The recommended treatment for Pseudomonas aeruginosa infections is:
- Piperacillin-tazobactam in combination with an aminoglycoside for nosocomial pneumonia 2
- Ciprofloxacin for skin and skin structure infections, bone and joint infections, and complicated intra-abdominal infections 3 Key considerations:
- The treatment should be based on the severity of the infection and the patient's renal function
- The dosage and duration of treatment should be adjusted according to the patient's response and the susceptibility of the organism
- Combination therapy with an aminoglycoside is recommended for nosocomial pneumonia caused by Pseudomonas aeruginosa 2
From the Research
Treatment Options for Pseudomonas aeruginosa Infections
The treatment of Pseudomonas aeruginosa infections typically involves the use of antipseudomonal agents, with the most commonly used being:
- Extended-spectrum penicillins
- Aminoglycosides
- Cephalosporins
- Fluoroquinolones
- Polymixins
- Monobactams As noted in 4, an aminoglycoside with a beta-lactam penicillin is usually considered to be the first line treatment.
Combination Therapy
Combination therapy is often used to treat Pseudomonas aeruginosa infections, with studies suggesting that the use of a beta-lactam plus an aminoglycoside is the standard for treating severe infections 5, 6. However, the use of fluoroquinolones as an alternative to aminoglycosides has also been explored, with some studies suggesting that the degree of synergy between a beta-lactam plus aminoglycoside and a beta-lactam plus fluoroquinolone is comparable 5.
New Treatment Options
Newer treatment options, such as ceftolozane-tazobactam and ceftazidime-avibactam, have been developed to target Pseudomonas aeruginosa isolates with limited treatment options 7. Other new antibiotics, such as cefiderocol, cefepime-taniborbactam, and cefepime-zidebactam, are also being explored as potential treatment options.
Monotherapy vs. Combination Therapy
A study comparing ceftazidime, carbapenems, and piperacillin-tazobactam as single definitive therapy for Pseudomonas aeruginosa bloodstream infection found no significant difference in mortality, clinical, and microbiological outcomes or adverse events between the three antibiotics 8. However, the study did note that the use of carbapenems was associated with a higher rate of resistant P. aeruginosa.
Nebulised Delivery of Antipseudomonal Antibiotics
Nebulised delivery of antipseudomonal antibiotics, such as colistin, tobramycin, and gentamicin, is also used to prevent recurrent exacerbations, reduce antibiotic usage, and maintain lung function, particularly in patients with cystic fibrosis 4.