What is the treatment for coagulase-negative Staphylococcus (CoNS) in urine?

Treatment of Coagulase-Negative Staphylococcus in Urine

In most cases, coagulase-negative staphylococci (CoNS) in urine should NOT be treated, as these organisms are typically contaminants or colonizers rather than true pathogens. 1

Determining Clinical Significance

The critical first step is distinguishing true infection from contamination or asymptomatic bacteriuria:

• CoNS are "not considered clinically relevant urine isolates" in the majority of cases, particularly in asymptomatic patients 1
• True infection requires both positive urine culture AND clinical symptoms (dysuria, frequency, urgency, suprapubic pain, fever) 1
• Asymptomatic bacteriuria should NOT be treated except in pregnancy, to avoid unnecessary antibiotic use and resistance development 1

When Treatment IS Indicated

Treatment should be considered only when BOTH of the following are present:

Clinical Symptoms Present

• Dysuria, frequency, urgency, or suprapubic pain for cystitis 1
• Fever, flank pain, or systemic symptoms for pyelonephritis 1

High-Risk Features Present

• Indwelling urinary catheter 2
• Recent urological procedure 1
• Immunocompromised status 1
• Pregnancy 1

Antibiotic Selection When Treatment Is Warranted

For uncomplicated CoNS UTI, trimethoprim-sulfamethoxazole (TMP-SMX) or a fluoroquinolone is first-line therapy: 2

First-Line Options for Uncomplicated Cystitis:

• TMP-SMX for 3 days (most appropriate for community-acquired CoNS) 1, 2
• Nitrofurantoin for 5 days (alternative first-line option) 1
• Fluoroquinolones (ciprofloxacin) when TMP-SMX cannot be used 2

For Pyelonephritis or Complicated UTI:

• First-generation cephalosporin for 7 days 1
• For systemic symptoms: amoxicillin plus aminoglycoside, second-generation cephalosporin plus aminoglycoside, or IV third-generation cephalosporin 1

For Methicillin-Resistant CoNS:

• Vancomycin is reserved for documented methicillin-resistant strains or treatment failure 2
• Linezolid is an alternative for patients who cannot tolerate vancomycin 2
• Avoid cephalosporins even if in vitro testing suggests susceptibility, as cross-resistance exists 2

Treatment Duration

Duration depends on complexity and catheter presence:

• Uncomplicated CoNS UTI: 5-7 days of appropriate antibiotic therapy 2
• Complicated infections or catheter-associated: 10-14 days 2
• If catheter is removed: 5-7 days of antibiotics 3
• If catheter is retained: 10-14 days with antibiotic lock therapy 3

Catheter Management

Catheter removal is often more important than antibiotics:

• Remove or replace urinary catheter when feasible 2
• Catheter removal alone may resolve infection without antibiotics in some cases 2
• If catheter cannot be removed, consider antibiotic lock therapy in addition to systemic antibiotics 2

Important Caveats

Common pitfalls to avoid:

• Do not treat asymptomatic bacteriuria (except in pregnancy) to prevent antibiotic resistance 1
• Always confirm CoNS is a true pathogen by assessing clinical symptoms and obtaining proper cultures 2
• Treatment should be guided by antimicrobial susceptibility testing when available 1
• Be aware that S. epidermidis shows higher resistance rates than S. saprophyticus to multiple antibiotics 4
• Methicillin resistance is common in nosocomial CoNS isolates 5, 6