What antibiotics are used to treat Providencia rettgeri infections?

Antibiotic Treatment for Providencia rettgeri Infections

The treatment of Providencia rettgeri infections should be guided by antimicrobial susceptibility testing, with third-generation cephalosporins like ceftriaxone being the first-line treatment option for most non-resistant strains. 1

Antibiotic Options Based on Susceptibility

First-Line Options

• Ceftriaxone is the most commonly used antibiotic (36.2% of cases) for Providencia rettgeri infections and remains an appropriate choice for susceptible strains 1
• Cefepime is another frequently used option (29% of cases) for P. rettgeri infections 1
• Ciprofloxacin has demonstrated in vitro activity against P. rettgeri according to FDA labeling 2

For Multidrug-Resistant Strains

• Carbapenems (meropenem) are recommended for multidrug-resistant P. rettgeri infections (used in 14.5% of cases) 1
• For carbapenem-resistant P. rettgeri, newer β-lactam/β-lactamase inhibitor combinations should be considered:
  • Ceftazidime-avibactam 2.5g IV q8h is recommended for complicated urinary tract infections caused by carbapenem-resistant Enterobacterales (CRE) 3
  • Meropenem-vaborbactam 4g IV q8h or imipenem-cilastatin-relebactam 1.25g IV q6h are alternatives for CRE infections 3

For Urinary Tract Infections

• Aminoglycosides can be effective for urinary tract infections caused by P. rettgeri 3
• Single-dose aminoglycoside is recommended for simple cystitis due to resistant strains 3
• Plazomicin 15 mg/kg IV q12h is recommended for complicated UTI due to resistant Enterobacterales 3

Site-Specific Recommendations

Bloodstream Infections

• For P. rettgeri bacteremia (the most common infection type at 55.8% of cases), ceftriaxone or cefepime are appropriate first-line options for susceptible strains 1
• For carbapenem-resistant bloodstream infections, ceftazidime-avibactam 2.5g IV q8h infused over 3 hours is recommended 3

Intra-abdominal Infections

• For intra-abdominal infections caused by carbapenem-resistant strains, ceftazidime-avibactam 2.5g IV q8h in combination with metronidazole is recommended 3
• Tigecycline (100mg IV loading dose then 50mg IV q12h) or eravacycline (1mg/kg IV q12h) are alternatives for intra-abdominal infections 3

Important Clinical Considerations

• P. rettgeri infections are most commonly seen in elderly patients and those with indwelling urinary catheters (65.2% of cases had urinary catheters) 1
• Only 7.2% of P. rettgeri cases were found to be multidrug-resistant in recent studies 1
• Antimicrobial susceptibility testing is crucial for guiding appropriate therapy, as resistance patterns can vary 1, 4
• P. rettgeri is naturally resistant to tetracyclines and fosfomycin but generally more susceptible to aminoglycosides, quinolones, and numerous β-lactam antibiotics compared to other Providencia species 4

Carbapenem-Resistant P. rettgeri Management

• For carbapenem-resistant strains, a multiprong approach is needed, including:
  • Appropriate antimicrobial therapy based on susceptibility testing 5
  • Stringent infection control practices to prevent nosocomial spread 5
  • For severe infections with limited treatment options, combination therapy may be considered 3

Pitfalls and Caveats

• P. rettgeri is emerging as an opportunistic pathogen with increasing antibiotic resistance, particularly in healthcare settings 5, 6
• Carbapenem resistance in P. rettgeri is often plasmid-mediated, requiring strict infection control measures to prevent spread 5
• Neonatal sepsis caused by P. rettgeri has been reported, requiring prompt diagnosis and treatment with appropriate antibiotics 6
• Avoid empiric use of tetracyclines and fosfomycin as P. rettgeri has natural resistance to these agents 4