From the Guidelines
Levofloxacin is effective against Proteus mirabilis infections, with a recommended dosage of 750 mg once daily for 5 days for mild cases and potentially longer for more complicated infections 1. This fluoroquinolone antibiotic works well against this gram-negative bacterium, which commonly causes urinary tract infections, wound infections, and sometimes pneumonia. The mechanism of action involves inhibiting bacterial DNA gyrase and topoisomerase IV, preventing DNA replication and ultimately killing the bacteria. However, resistance to fluoroquinolones has been increasing in recent years, so susceptibility testing is recommended before starting treatment 1. Patients should take the full course of antibiotics even if symptoms improve, drink plenty of fluids, and be aware of potential side effects including tendon inflammation, GI disturbances, and QT interval prolongation. Alternative antibiotics for Proteus mirabilis include trimethoprim-sulfamethoxazole, ampicillin, cephalosporins, and carbapenems if fluoroquinolone resistance is a concern 1. Key considerations in the treatment of Proteus mirabilis infections include:
- Local antimicrobial resistance patterns, which can guide empirical treatment choices 1
- The severity of the infection, which may necessitate different durations of treatment or different antibiotics 1
- Patient factors, such as allergies or previous antibiotic use, which can influence the choice of antibiotic 1
From the FDA Drug Label
Levofloxacin tablets are indicated for the treatment of complicated skin and skin structure infections due to methicillin-susceptible Staphylococcus aureus, Enterococcus faecalis, Streptococcus pyogenes, or Proteus mirabilis Levofloxacin tablets are indicated for the treatment of complicated urinary tract infections due to Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis Levofloxacin tablets are indicated for the treatment of complicated urinary tract infections (mild to moderate) due to Enterococcus faecalis, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, or Pseudomonas aeruginosa
Levofloxacin is effective against Proteus mirabilis in the treatment of:
- Complicated skin and skin structure infections
- Complicated urinary tract infections 2
From the Research
Effectiveness of Levofloxacin against Proteus mirabilis
- Levofloxacin has been shown to be effective against Proteus mirabilis in various studies 3, 4.
- A study comparing the antibacterial activities of levofloxacin and ciprofloxacin against urinary tract pathogens found that levofloxacin was effective against Proteus mirabilis 3.
- Another study found that female patients with Proteus mirabilis infections responded best to levofloxacin 4.
- However, the effectiveness of levofloxacin against Proteus mirabilis can be influenced by various factors, including antibiotic resistance 5, 6.
- A longitudinal nationwide study found that susceptibility to ciprofloxacin, a fluoroquinolone antibiotic, decreased significantly in Proteus mirabilis isolates over a decade 6.
Antibiotic Resistance in Proteus mirabilis
- Proteus mirabilis is naturally resistant to several antibiotics, including colistin, and shows reduced susceptibility to imipenem 5.
- The emergence and spread of multidrug-resistant Proteus mirabilis isolates, including those producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases, are being increasingly reported 5.
- A study found that the prevalence of ESBL-producing Proteus mirabilis remained stable, but AmpC beta-lactamase-producing isolates increased significantly over the years 6.
- The revised Clinical and Laboratory Standards Institute (CLSI) beta-lactam breakpoints had a significant impact on susceptibility rates and the detection of ESBL and AmpC beta-lactamase-producers in Proteus mirabilis 6.