From the Guidelines
Mixed urogenital flora is typically considered a contaminant and does not require antibiotic treatment, instead, a repeat sample should be collected using proper technique to minimize contamination. This approach is supported by the latest guidelines from the European Association of Urology, which emphasize the importance of antimicrobial stewardship and proper diagnosis to combat the rising threat of antimicrobial resistance 1.
Key Considerations
- Mixed urogenital flora usually indicates sample contamination rather than a true infection
- No specific treatment is recommended for mixed flora results alone
- Proper collection technique should be used for a repeat sample, including clean-catch midstream urine collection and thorough cleansing of the genital area
- Clinical judgment may warrant empiric antibiotic treatment if symptoms of urinary tract infection are present, while awaiting repeat culture results 1
Clinical Implications
- The urinary tract is normally sterile above the urethra, while the external genitalia naturally harbor various bacteria that don't cause disease unless they enter normally sterile sites in significant numbers
- Avoiding unnecessary antibiotic treatment for mixed flora results can help reduce the risk of antimicrobial resistance and promote better patient outcomes
- Repeat urine culture should be obtained if a patient has persistent symptoms despite treatment, to assess for ongoing bacteriuria before prescribing additional antibiotics 1
From the Research
Mixed Urogenital Flora
- Mixed urogenital flora, which includes Lactobacillus species, coagulase-negative staphylococci, and Streptococcus species, can be a contaminant in urine cultures 2
- A study found that clean-catch urine specimens were more likely to be contaminated with mixed urogenital flora than straight catheter urine specimens, with a contamination rate of 53.7% vs 23.1% 2
- The presence of mixed urogenital flora in urine cultures can lead to misdiagnosis of urinary tract infections and antibiotic overuse 2
- Anaerobic bacteria, which can be part of the mixed urogenital flora, are a common cause of endogenous infections and require appropriate treatment with antimicrobials such as metronidazole, carbapenems, and clindamycin 3
- The treatment of anaerobic infections, including those caused by mixed urogenital flora, is complicated by the slow growth of these organisms and the growing resistance of anaerobic bacteria to antimicrobials 3
Diagnosis and Treatment
- Accurate diagnosis of urinary tract infections is essential to postoperative care, especially after vaginal surgery for pelvic organ prolapse 2
- The use of clean-catch urine specimens may not be reliable for diagnosing urinary tract infections in women who have recently undergone vaginal surgery, and straight catheter urine specimens may be preferred 2
- Antimicrobials such as cephalosporins, including ceftriaxone and cefixime, may be effective in treating enteric fever and other infections caused by mixed urogenital flora, but the choice of antimicrobial should be based on current, local resistance patterns 4, 5, 6