Pseudomonas aeruginosa Infections Medication

Updated: Mar 03, 2023
  • Author: Shahab Qureshi, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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Medication Summary

Pseudomonal infections are increasingly resistant to certain antibiotics, and the organism may acquire resistance during therapy. Two agents from different classes should be used when the risk for antibiotic resistance is high (eg, in severe sepsis, septicemia, and inpatient neutropenia).

Pseudomonas infection can be treated with a combination of an antipseudomonal beta-lactam (eg, penicillin or cephalosporin) and an aminoglycoside. Carbapenems (eg, imipenem, meropenem) with antipseudomonal quinolones may be used in conjunction with an aminoglycoside. With the exception of cases involving febrile patients with neutropenia, in whom monotherapy with ceftazidime or a carbapenem (eg, imipenem, meropenem) is used, a 2-drug regimen is recommended.



Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.


Aminoglycoside antibiotic for gram-negative coverage. Used in combination with both an agent against gram-positive organisms and one that covers anaerobes.

Not the DOC. Consider if penicillins or other less toxic drugs are contraindicated, when clinically indicated, and in mixed infections caused by susceptible staphylococci and gram-negative organisms.

Dosing regimens are numerous. Adjust dose based on CrCl and changes in volume of distribution. May be administered IV/IM.

Piperacillin and tazobactam (Zosyn)

Antipseudomonal penicillin plus beta-lactamase inhibitor. Inhibits biosynthesis of cell wall and is effective during stage of active multiplication.

Aztreonam (Azactam)

Monobactam that inhibits cell wall synthesis during bacterial growth. Active against gram-negative bacilli but very limited gram-positive activity and not useful for anaerobes. Lacks cross-sensitivity with beta-lactam antibiotics. May be used in patients allergic to penicillins or cephalosporins.

Ciprofloxacin (Cipro, Cipro XR)

Exerts bactericidal effect against both actively dividing and dormant bacteria. Fluoroquinolone effective against pseudomonads, streptococci, some MRSA, Staphylococcus epidermidis, and most gram-negative organisms but no activity against anaerobes. Inhibits bacterial DNA synthesis and, consequently, growth. Continue treatment for at least 2 d (7-14 d typical) after signs and symptoms disappear.

Cefepime (Maxipime)

For the treatment of Pseudomonas infections. Fourth-generation cephalosporin. Gram-negative coverage comparable to ceftazidime but has better gram-positive coverage. Cefepime is a zwitterion that rapidly penetrates gram-negative cells. Best beta-lactam for IM administration. Poor capacity to cross blood-brain barrier precludes use for treatment of meningitis.

Ceftazidime (Fortaz, Tazicef)

Third-generation cephalosporin with high activity against Pseudomonas. Arrests bacterial growth by binding to 1 or more penicillin-binding proteins.


Obtained from Streptomyces tenebrarius. Two to 4 times more active against pseudomonal organisms as compared to gentamicin.

Meropenem (Merrem)

Ultra–broad-spectrum beta-lactam semisynthetic carbapenem antibiotic that inhibits bacterial cell wall synthesis.

Doripenem (Doribax)

Binds to several of penicillin-binding proteins, which in turn inhibit bacterial cell wall synthesis. Bacteria eventually lyse due to ongoing cell wall autolytic enzymes.

Ceftazidime/avibactam (Avycaz)

Ceftazidime/avibactam (Avycaz) is a combination cephalosporin and beta-lactamase inhibitor that was FDA-approved in February 2015. The ceftazidime component has activity against gram-negative bacteria, including P aeruginosa. The addition of avibactam increases the spectrum of activity to organisms that produce beta-lactamase enzymes. Unlike other beta-lactam/beta-lactamase inhibitors, however, this drug has no activity against anaerobic organisms.

Ceftazidime/avibactam is indicated for the treatment of patients aged 18 years or older with complicated intra-abdominal infections and complicated UTIs. Phase II clinical trials for ceftazidime/avibactam have shown an 85.7% favorable clinical response rate for complicated UTIs and 92.7% favorable clinical response rate for complicated intra-abdominal infections when combined with metronidazole. Full results from the phase III trials and future studies are likely to expand the use of ceftazidime/avibactam to include hospitalized adults with nosocomial and ventilator-associated pneumonia, hospitalized pediatric patients aged 3 months to 18 years with complicated intra-abdominal infections, and patients with cystic fibrosis who have resistant respiratory P aeruginosa infections.

Ceftolozane/tazobactam (Zerbaxa)

Ceftolozane/tazobactam is a novel cephalosporin developed with a beta-lactamase inhibitor for the treatment of complicated UTIs, complicated intra-abdominal infections, and ventilator-associated bacterial pneumonia. Ceftolozane has similar activity to that of ceftazidime, piperacillin/tazobactam, and the carbapenemase family of antibiotics. The tazobactam component allows for the drug to act against extended-spectrum beta-lactamase (ESBL) bacteria, as well as some anaerobic species, although data from previous Phase III trials show that, for anaerobic coverage, combining ceftolozane/tazobactam with metronidazole is recommended.

Ceftolozane/tazobactam is a promising carbapenem-sparing alternative agent for the treatment of complicated UTIs and complicated intra-abdominal infections, including those caused by ESBL-producing Enterobacteriaceae and multidrug-resistant P aeruginosa.