From the Guidelines
Staphylococcus epidermidis in urine is typically considered a contaminant rather than a true urinary tract infection (UTI). When S. epidermidis is isolated from a urine culture, it usually represents contamination from the skin during sample collection, as this bacterium is a normal part of skin flora. No specific treatment is generally required unless there are clinical symptoms of UTI along with significant colony counts (>100,000 CFU/mL) and no other likely contaminants in the sample.
If treatment is deemed necessary based on symptoms and clinical presentation, empiric antibiotic options can be considered, but the most recent and highest quality study 1 emphasizes the importance of antimicrobial stewardship to combat the rising threat of antimicrobial resistance. The 2024 European Association of Urology guidelines on urological infections provide recommendations for antibiotic selection, dosing, and duration based on the latest evidence.
Some key points to consider in the management of S. epidermidis in urine include:
- Proper collection technique to avoid false positives in future urine cultures, including thorough cleansing of the genital area before collection and using the clean-catch midstream technique.
- Clinical correlation is always necessary when interpreting urine culture results, especially in patients with urinary catheters, immunocompromise, or urological abnormalities, as S. epidermidis can occasionally cause true infections in these cases.
- The potential for antimicrobial resistance and the need for judicious use of antibiotics, as highlighted by the guidelines and studies such as 1, which discuss the consideration of antimicrobial resistance in the treatment of acute uncomplicated cystitis and pyelonephritis.
Given the emphasis on antimicrobial stewardship and the potential for S. epidermidis to be a contaminant, treatment should be approached with caution and based on clinical symptoms and susceptibility results, rather than solely on the presence of S. epidermidis in the urine culture.
From the Research
Staphylococcus epidermidis in Urine
- Staphylococcus epidermidis is a common cause of nosocomial infections, including those related to indwelling medical devices 2, 3.
- It is also a frequent cause of primary bacteremia and infections of indwelling medical devices 4.
- The ability of S. epidermidis to form biofilms contributes to its success as a pathogen and makes it more resistant to antimicrobials 2.
- S. epidermidis has been involved in the development of resistance to several antibiotics, including methicillin and linezolid 5, 6.
- Studies have shown that S. epidermidis isolates are susceptible to certain antimicrobial agents, such as vancomycin, linezolid, daptomycin, and tigecycline 5, 6.
- However, there is evidence of increasing resistance to some of these agents, highlighting the need for continued monitoring and development of new treatment strategies 6.
Clinical Characteristics and Treatment
- S. epidermidis infections can be challenging to treat due to their ability to form biofilms and develop resistance to antimicrobials 2, 4.
- The treatment of S. epidermidis infections often requires the use of antimicrobial agents that are effective against biofilm-forming bacteria 2.
- Ceftaroline, a new cephalosporin, has been shown to be effective against methicillin- and linezolid-resistant S. epidermidis isolates 5.
- Other antimicrobial agents, such as tigecycline, daptomycin, and vancomycin, may also be effective against S. epidermidis infections 5, 6.
Epidemiology and Prevention
- S. epidermidis is a common commensal organism on human skin, and its ability to attach to and form biofilms on foreign bodies contributes to its pathogenicity 4, 3.
- The epidemiology of S. epidermidis infections is complex, and prevention strategies may include measures to reduce the risk of device-associated infections and promote appropriate antimicrobial use 2, 3.