Oral Antibiotic Treatment for Coagulase-Negative Staphylococcus UTI
For coagulase-negative staphylococcus (CoNS) urinary tract infections, trimethoprim-sulfamethoxazole (TMP-SMX) or a fluoroquinolone (ciprofloxacin or levofloxacin) are the preferred oral antibiotics, with treatment duration of 5-7 days if uncomplicated. 1
Treatment Approach
First-Line Oral Options
- TMP-SMX is a reasonable first-line choice for CoNS UTI, particularly when local resistance rates are acceptable (<10-20%) 1
- Fluoroquinolones (ciprofloxacin 500 mg twice daily or levofloxacin 750 mg once daily) are highly effective alternatives with excellent urinary concentrations and activity against CoNS 2, 3, 4
- Nitrofurantoin (5 days) can be considered for uncomplicated cystitis due to CoNS, though data are more limited for staphylococcal species compared to gram-negative organisms 1, 5
Treatment Duration
- 5-7 days is appropriate for uncomplicated CoNS UTI with catheter removal 1
- 10-14 days may be warranted if the catheter remains in place or if there are complicating factors 1
- For catheter-associated infections, replace the catheter if it has been in place ≥2 weeks before initiating antimicrobial therapy to improve outcomes 1
Key Clinical Considerations
Fluoroquinolone Use
- Ciprofloxacin and levofloxacin achieve excellent urinary concentrations that exceed the minimum inhibitory concentrations for CoNS throughout the dosing interval 3, 6
- However, fluoroquinolones should be reserved for situations where other options are unsuitable due to concerns about collateral damage, C. difficile risk, and antimicrobial stewardship 1
- The FDA has issued warnings against fluoroquinolone use for uncomplicated UTIs due to unfavorable risk-benefit ratios 1
Alternative Considerations
- Cephalexin (first-generation cephalosporin) may be used but has higher rates of recurrence and collateral damage compared to nitrofurantoin 1
- Fosfomycin (single 3-g dose) is an option for uncomplicated cystitis, though evidence specifically for CoNS is limited 1, 5
Important Caveats
- Always obtain urine culture before initiating therapy to confirm CoNS as the causative pathogen and guide definitive treatment based on susceptibilities 1
- CoNS are the most common cause of catheter-related infections and typically have a benign clinical course 1
- Staphylococcus lugdunensis is an exception among CoNS species and should be treated more aggressively, similar to S. aureus infections 1
- If the patient is asymptomatic with CoNS bacteriuria and no systemic signs, observation without antibiotics may be appropriate after catheter removal, with repeat cultures to confirm clearance 1
Catheter Management
- For catheter-associated CoNS UTI, catheter removal is critical whenever possible 1
- If the catheter must remain, consider antibiotic lock therapy (vancomycin 5 mg/mL) in combination with systemic antibiotics for 10-14 days 1
- Obtain urine specimens from a freshly placed catheter rather than from an established biofilm-colonized catheter for accurate culture results 1