What is the recommended treatment for Providencia stuartii infections?

Treatment of Providencia stuartii Infections

Third-generation cephalosporins like ceftriaxone are the recommended first-line treatment for Providencia stuartii infections, with carbapenems reserved for multidrug-resistant cases. 1

Antimicrobial Selection Based on Infection Type

First-Line Options:

• Ceftriaxone: 1g IV every 24 hours (recommended for most uncomplicated infections) 1
• Cefepime: 1-2g IV every 12 hours (for more severe infections) 1

For Multidrug-Resistant Strains:

• Meropenem: 1g IV every 8 hours 1
• Imipenem-cilastatin: 500mg IV every 6 hours 2

Treatment Algorithm Based on Infection Site

Urinary Tract Infections (Most Common)

1. Uncomplicated UTI: Ceftriaxone 1g IV daily for 7-10 days 3, 1
2. Complicated UTI/Catheter-associated: Cefepime 2g IV every 12 hours for 10-14 days 3, 1
3. MDR strains: Meropenem 1g IV every 8 hours 1

Bacteremia

1. Initial therapy: Cefepime 2g IV every 8-12 hours 1
2. Alternative: Imipenem-cilastatin 500mg IV every 6 hours 2
3. Duration: 10-14 days based on clinical response 3

Skin and Soft Tissue Infections

1. Wound infections: Ceftazidime 2g IV every 8 hours 3
2. Alternative: Ciprofloxacin 400mg IV every 12 hours (if susceptible) 3
3. Duration: 7-14 days based on clinical response 3

Special Considerations

Risk Factors to Address

• Urinary catheters: Remove or replace if possible, as 65.2% of P. stuartii infections are associated with catheterization 1
• Biofilm formation: Consider longer treatment duration for catheter-associated infections 4
• Long-term care facility residence: Higher risk for multidrug-resistant strains 5

Antimicrobial Resistance Patterns

• Only 7.2% of P. stuartii isolates show multidrug resistance requiring carbapenem therapy 1
• P. stuartii is naturally resistant to colistin and tigecycline, limiting options for extensively resistant strains 5
• Resistance mechanisms include production of β-lactamases (TEM-1, SHV-5, VEB-1, VIM-1) and 16S rDNA methylases (RmtB) 6

Monitoring and Follow-up

• Obtain cultures before initiating antibiotics to guide therapy 3
• Assess clinical response within 48-72 hours of starting treatment 7
• Consider repeat cultures in patients with persistent symptoms 3

Emerging Therapies

For highly resistant strains where conventional antibiotics fail, bacteriophage therapy may be considered as an investigational approach. Bacteriophages have shown promising results in eradicating biofilm-forming P. stuartii strains in catheter models 4.

Treatment Pitfalls to Avoid

1. Delayed recognition: P. stuartii is often misidentified as a contaminant rather than a pathogen, especially in elderly patients
2. Inadequate catheter management: Failure to remove or replace urinary catheters can lead to persistent infection
3. Empiric therapy without susceptibility testing: Given the variable resistance patterns, treatment should be guided by susceptibility results when available
4. Underestimating biofilm formation: P. stuartii forms robust biofilms, particularly on catheters, which may require more aggressive or prolonged therapy

Remember that P. stuartii infections primarily affect elderly, catheterized patients, with bacteremia and UTIs being the most common presentations. While mortality can be high in this population (27.1%), deaths are typically related to underlying conditions rather than the infection itself 1.