Is ciprofloxacin (Cipro) effective against Morganella morganii infections?

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From the Guidelines

Ciprofloxacin can be used to treat Morganella morganii infections, but its effectiveness may vary depending on the susceptibility of the specific strain and the severity of the infection. According to a case study published in 2020 in the journal Clinical Microbiology and Infection 1, a patient with a complex prosthetic joint infection (PJI) caused by M. morganii, among other organisms, was treated with oral ciprofloxacin and pristinamycin after initial intravenous therapy with teicoplanin and meropenem. The patient showed improvement, with the sinus tract healing within 3 months, and remained well with good quality of life and minimal discomfort in the joint.

Key Considerations

  • The study highlights the importance of susceptibility testing, as the S. epidermidis isolated in this case was multi-resistant, including to ciprofloxacin 1.
  • Ciprofloxacin is a fluoroquinolone antibiotic that typically shows good activity against gram-negative bacteria like M. morganii.
  • However, resistance to ciprofloxacin among M. morganii strains has been increasing, making susceptibility testing crucial before initiating treatment 1.

Treatment Approach

  • For uncomplicated infections, ciprofloxacin 500 mg orally twice daily for 7 days may be effective.
  • For more severe infections, higher doses of 750 mg twice daily may be needed, potentially with initial intravenous therapy before transitioning to oral treatment.
  • Alternative antibiotics for resistant strains might include carbapenems, fourth-generation cephalosporins, or aminoglycosides, depending on susceptibility results.

From the FDA Drug Label

Ciprofloxacin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections... Aerobic gram-negative microorganisms ... Morganella morganii

  • Ciprofloxacin spectrum of activity: includes Morganella morganii
  • Treatment: Ciprofloxacin can be used to treat Morganella morganii infections, as it has been shown to be active against this microorganism in vitro and in clinical infections 2
  • Key consideration: The susceptibility of the specific Morganella morganii strain to ciprofloxacin should be confirmed by susceptibility testing, if possible.

From the Research

Antibiotic Treatment of Morganella morganii

  • Ciprofloxacin can be used to treat Morganella morganii infections, as seen in a case report where a patient with peritonitis due to M. morganii was treated successfully with intraperitoneal tobramycin followed by oral ciprofloxacin 3.
  • However, M. morganii is often resistant to multiple antibiotics, including ciprofloxacin, as found in a retrospective study of M. morganii bloodstream infections 4.
  • Another study found that M. morganii was susceptible to ceftazidime, imipenem, and amikacin, but the majority of patients were treated with gentamicin, often in combination with a third-generation cephalosporin or another antibiotic 5.
  • An epidemiological surveillance study found that M. morganii showed a significant decrease in antibiotic susceptibility over an 11-year period, but gentamicin, ciprofloxacin, imipenem, and cefepime still showed susceptibility over 80% 6.

Effectiveness of Ciprofloxacin

  • A study found that six patients with M. morganii infections were treated with ciprofloxacin, but the outcome of these patients was not specified 7.
  • Another study found that ciprofloxacin was used to treat M. morganii bacteremia, but the effectiveness of this treatment was not compared to other antibiotics 4.
  • The use of ciprofloxacin to treat M. morganii infections is supported by a case report, but more research is needed to determine its effectiveness in different patient populations and infection types 3.

Resistance to Ciprofloxacin

  • M. morganii is often resistant to ciprofloxacin, as found in a retrospective study of M. morganii bloodstream infections 4.
  • An epidemiological surveillance study found that M. morganii showed a significant decrease in antibiotic susceptibility over an 11-year period, including a decrease in susceptibility to ciprofloxacin 6.
  • The development of resistance to ciprofloxacin and other antibiotics is a concern, and more research is needed to understand the mechanisms of resistance and to develop effective treatment strategies 5.

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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