What is the effectiveness of Zosyn (piperacillin/tazobactam) in treating Moraxella catarrhalis infections in Intensive Care Unit (ICU) patients?

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From the Guidelines

Zosyn (piperacillin-tazobactam) is a recommended treatment option for Moraxella catarrhalis infections in ICU patients, particularly in cases of late pneumonia or presence of other risk factors for nonfermenting Gram-negative bacilli, as it is a b-lactam active against P. aeruginosa. According to the study published in Anaesthesia in 2018 1, the suggested protocol for treatment options includes piperacillin-tazobactam as a viable choice. The dosing regimen for piperacillin-tazobactam is 16 g/d, which is suitable for patients with normal renal function and standard weight.

Some key points to consider when treating Moraxella catarrhalis infections in ICU patients include:

  • The risk factors for non-fermenting Gram-negative bacilli, such as antibiotic therapy in the previous 90 days, prior hospital stay of more than 5 days, renal replacement therapy requirement during pneumonia, septic shock, and acute respiratory distress syndrome 1.
  • The importance of susceptibility testing to guide therapy, especially when using broad-spectrum antibiotics like Zosyn 1.
  • The need to monitor for clinical improvement within 48-72 hours and adjust treatment accordingly 1.
  • The consideration of obtaining sputum cultures before antibiotics if possible to ensure adequate treatment 1.

It is essential to note that the treatment of Moraxella catarrhalis infections in ICU patients should be guided by the most recent and highest-quality evidence, and piperacillin-tazobactam is a suitable option in certain cases, as recommended by the 2018 study published in Anaesthesia 1.

From the Research

Moraxella catarrhalis Infections

  • Moraxella catarrhalis is a human-restricted commensal that has developed into an emerging respiratory tract pathogen over the last two decades 2.
  • It is a common cause of respiratory infections, particularly otitis media in children and lower respiratory tract infections in the elderly 3, 4, 5.
  • The bacterial species is equipped with various adhesins to facilitate its colonization, and successful evasion of the human immune system is a prerequisite for Moraxella infection 2.

Treatment of Moraxella catarrhalis Infections

  • Cephalosporins and beta-lactamase inhibitor combinations, such as Zosyn, are effective for treatment of beta-lactamase-producing Moraxella catarrhalis 3.
  • The organism remains nearly universally susceptible to macrolides, fluoroquinolones, tetracyclines, and the combination of trimethoprim and sulfamethoxazole 3.
  • In ICU patients, the choice of antibiotic therapy should be guided by susceptibility testing and clinical experience 6.

Moraxella catarrhalis in ICU Patients

  • Infective Endocarditis (IE) caused by Moraxella spp. is rare, but can be problematic due to the lack of experience in their management 6.
  • A systematic review of published cases of IE by Moraxella spp. found that cephalosporins, aminoglycosides, aminopenicillins, and penicillin were the most commonly used antimicrobials 6.
  • The overall mortality rate for IE caused by Moraxella spp. was 12.9% 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Moraxella catarrhalis: clinical significance, antimicrobial susceptibility and BRO beta-lactamases.

European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 1998

Research

Moraxella catarrhalis - pathogen or commensal?

Advances in experimental medicine and biology, 2011

Research

Moraxella catarrhalis, a human respiratory tract pathogen.

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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