Treatment of Staphylococcal Urinary Tract Infection
For severe staphylococcal UTI, initiate intravenous vancomycin as first-line therapy, as it is the gold standard for methicillin-resistant staphylococcal infections and is FDA-approved for serious staphylococcal infections including urinary tract involvement. 1
Initial Empiric Therapy
For severe or complicated staphylococcal UTI with systemic symptoms, treatment should follow the approach for complicated UTIs:
Use combination therapy with amoxicillin plus an aminoglycoside, a second-generation cephalosporin plus an aminoglycoside, or an intravenous third-generation cephalosporin as empirical treatment for complicated UTI with systemic symptoms 2
However, if staphylococcal infection is suspected or confirmed (particularly MRSA), vancomycin should be the primary agent as it is specifically indicated for serious infections caused by methicillin-resistant staphylococci 1
Pathogen-Specific Considerations
Staphylococcal UTIs require special consideration because:
Staphylococcus species (including Enterococcus) are among the common organisms found in complicated UTI cultures, alongside E. coli, Proteus, Klebsiella, Pseudomonas, and Serratia 2
For methicillin-susceptible Staphylococcus aureus (MSSA), penicillinase-resistant penicillins (flucloxacillin, dicloxacillin) remain the antibiotics of choice for serious infections, with first-generation cephalosporins (cefazolin) as alternatives 3
For methicillin-resistant Staphylococcus aureus (MRSA), all serious infections should be treated with parenteral vancomycin or teicoplanin if vancomycin-allergic 3
Treatment Duration and Monitoring
Treatment duration should be 7 to 14 days (14 days for men when prostatitis cannot be excluded) 2
When the patient is hemodynamically stable and has been afebrile for at least 48 hours, a shorter treatment duration (7 days) may be considered 2
Obtain urine culture and susceptibility testing before initiating therapy, then tailor initial empiric therapy based on culture results 2
Critical Management Principles
Address any underlying urological abnormality or complicating factor, as this is mandatory for successful treatment 2
Common complicating factors to identify and manage include:
- Obstruction at any site in the urinary tract 2
- Foreign body (catheter) 2
- Incomplete voiding 2
- Recent instrumentation 2
- Healthcare-associated infection 2
- Immunosuppression 2
Alternative Agents
If vancomycin cannot be used or for less severe infections:
Linezolid is recommended for oral or IV treatment of skin and skin structure infections caused by MRSA, though its role in UTI is less established 4
Daptomycin should be considered for MRSA bacteremia and complicated infections, but should NOT be used for pneumonia (its role in UTI requires culture confirmation) 4
For community-acquired non-multiresistant MRSA strains causing less serious infections, clindamycin or trimethoprim-sulfamethoxazole may be used 3
Special Situations
For catheter-associated staphylococcal UTI, treat according to complicated UTI recommendations and remove or replace the catheter if possible 2
Combination therapy with vancomycin plus clarithromycin may be considered for MRSA UTI with biofilm formation, as clarithromycin has demonstrated inhibitory action on MRSA glycocalyx and biofilm 5
Key Pitfalls to Avoid
Do not use fluoroquinolones empirically in patients from urology departments or those who have used fluoroquinolones in the last 6 months 2
Do not use daptomycin for respiratory tract infections as it is inactivated by pulmonary surfactant 4
Avoid treating asymptomatic bacteriuria unless the patient is pregnant or undergoing invasive urinary procedures 2
Do not delay appropriate antimicrobial therapy in patients with systemic symptoms, as mortality associated with healthcare-associated bacteremia from urinary sources is approximately 10% 2