Is Pseudomonas typically sensitive to Piperacillin-Tazobactam (Pip-Taz, piperacillin-tazobactam)?

From the Guidelines

Pseudomonas aeruginosa is generally sensitive to piperacillin-tazobactam (pip-tazo), making it an appropriate empiric choice for suspected Pseudomonas infections. Pip-tazo combines the extended-spectrum penicillin piperacillin with the beta-lactamase inhibitor tazobactam, providing good coverage against many Pseudomonas strains 1. However, resistance rates vary significantly by region and institution, with some hospitals reporting resistance rates of 10-20% or higher. For this reason, local antibiogram data should guide treatment decisions whenever possible. In critically ill patients or those with risk factors for resistant strains, combination therapy (adding an aminoglycoside or fluoroquinolone) may be considered initially until susceptibility results are available 1. The typical dosing for pip-tazo is 4.5g IV every 6-8 hours (adjusted for renal function), with extended infusions (over 3-4 hours) sometimes used to optimize efficacy against Pseudomonas.

Some key points to consider when using pip-tazo for Pseudomonas infections include:

• The importance of local antibiogram data in guiding treatment decisions 1
• The potential for resistance to develop during treatment, highlighting the need for regular monitoring of susceptibility patterns 1
• The consideration of combination therapy in critically ill patients or those with risk factors for resistant strains 1
• The use of alternative regimens, such as cefepime, imipenem, or meropenem, in patients with specific risk factors or allergies 1

Overall, pip-tazo remains a viable option for the treatment of Pseudomonas infections, but its use should be guided by local resistance patterns and patient-specific factors.

From the FDA Drug Label

Piperacillin and tazobactam has been shown to be active against most isolates of the following microorganisms, both in vitro and in clinical infections [see Indications and Usage (1)] Aerobic bacteria Gram-positive bacteria Staphylococcus aureus (methicillin susceptible isolates only) Gram-negative bacteria Acinetobacter baumannii Escherichia coli Haemophilus influenzae (excluding beta-lactamase negative, ampicillin-resistant isolates) Klebsiella pneumoniae Pseudomonas aeruginosa (given in combination with an aminoglycoside to which the isolate is susceptible)

Pseudomonas aeruginosa is typically sensitive to piperacillin/tazobactam, but it should be given in combination with an aminoglycoside to which the isolate is susceptible 2.

From the Research

Sensitivity of Pseudomonas to Pip-Tazo

• Pseudomonas aeruginosa is a common gram-negative bacterium that can be resistant to various antibiotics, including imipenem 3.
• However, studies have shown that piperacillin/tazobactam can be effective against Pseudomonas aeruginosa, especially when the minimum inhibitory concentration (MIC) is low 3, 4.
• One study reported a case of a patient with severe pneumonia caused by imipenem-resistant Pseudomonas aeruginosa, which was successfully treated with piperacillin/tazobactam monotherapy 3.
• Another study compared the synergistic activities of piperacillin/tazobactam and cefepime when combined with gentamicin, ciprofloxacin, or levofloxacin against Pseudomonas aeruginosa, and found that all combinations were bactericidal 5.
• Extended-infusion dosing strategies for piperacillin/tazobactam have also been shown to improve clinical outcomes in patients with Pseudomonas aeruginosa infections 4, 6.
• A review of piperacillin/tazobactam's use in the treatment of bacterial infections found that it is effective against a broad spectrum of gram-positive and gram-negative aerobic and anaerobic bacteria, including Pseudomonas aeruginosa 7.

Factors Affecting Sensitivity

• The MIC of piperacillin/tazobactam is an important factor in determining its effectiveness against Pseudomonas aeruginosa 3, 4.
• The dosing strategy used can also impact the effectiveness of piperacillin/tazobactam, with extended-infusion dosing strategies showing improved clinical outcomes 4, 6.
• Combination therapy with other antibiotics, such as aminoglycosides, can also enhance the effectiveness of piperacillin/tazobactam against Pseudomonas aeruginosa 5, 7.