From the Guidelines
For preoperative patients with asymptomatic bacteriuria due to E. coli, antimicrobial treatment is recommended prior to urologic procedures involving mucosal trauma, and a short course of targeted antimicrobial therapy, such as trimethoprim-sulfamethoxazole or nitrofurantoin, should be prescribed based on susceptibility testing results. This recommendation is based on the strongest and most recent evidence from the Infectious Diseases Society of America (IDSA) guidelines, which suggest that treating asymptomatic bacteriuria before urologic procedures reduces the risk of post-operative bacteremia and sepsis 1.
When choosing an antibiotic, it is essential to consider local resistance patterns and patient-specific factors such as allergies, renal function, and pregnancy status. A urine culture should be obtained before starting antibiotics to confirm the diagnosis and guide therapy based on susceptibility results. According to the IDSA guidelines, a short course (1 or 2 doses) of antimicrobial therapy is suggested for patients with ASB who will undergo a urologic procedure, with treatment initiated 30–60 minutes before the procedure 1.
The IDSA guidelines also recommend screening for and treating ASB prior to surgery for patients who will undergo endoscopic urologic procedures associated with mucosal trauma, as this reduces the risk of postoperative complications, including sepsis 1. However, for non-urologic surgeries, treatment of asymptomatic bacteriuria has not been shown to significantly improve outcomes, and the decision to treat should be made on a case-by-case basis, considering the individual patient's risk factors and the potential benefits and harms of treatment 1.
In terms of specific antibiotic regimens, trimethoprim-sulfamethoxazole (160/800 mg twice daily) or nitrofurantoin (100 mg twice daily) may be appropriate options, depending on the susceptibility results and patient-specific factors. Ciprofloxacin (250-500 mg twice daily) may also be considered, although its use should be guided by local resistance patterns and patient-specific factors. Ultimately, the choice of antibiotic and duration of treatment should be individualized based on the patient's specific needs and the results of susceptibility testing.
From the Research
Treatment of Asymptomatic Bacteriuria
- The treatment of asymptomatic bacteriuria (ASB) due to Escherichia coli (E coli) in preoperative patients is not universally recommended, as it may not reduce the risk of postoperative symptomatic urinary tract infections (UTIs) 2, 3.
- According to the National S3 guideline on uncomplicated urinary tract infection, ASB should only be treated in exceptional cases, such as pregnant women or prior to expected mucocutaneous traumatising interventions of the urinary tract 4.
- A study published in JAMA Surgery found that receipt of antimicrobial therapy with activity against ASB organisms identified in preoperative urine cultures was not associated with reductions in the risk for postoperative infections, including UTI and surgical-site infection (SSI) 2.
- Another study published in Urology found that the preoperative presence of ASB was not associated with a higher incidence of postoperative symptomatic UTI in patients undergoing urologic surgical procedures who received antimicrobial prophylaxis in accordance with European Association of Urology guidelines 3.
Antibiotic Choice
- The choice of antibiotic for treating ASB due to E coli should be based on the antibiotic susceptibility pattern of the isolate, as well as the patient's individual risk factors and medical history 4, 5.
- Fosfomycin, nitrofurantoin, and pivmecillinam are recommended as first-line antibiotics for empiric therapy of frequent uncomplicated cystitis, as they have a lower risk of "collateral damage" compared to fluoroquinolones and group 3 cephalosporins 4.
- However, the susceptibility pattern of E coli strains isolated from ASB may not always predict the susceptibility pattern of subsequent symptomatic UTI isolates, highlighting the need for careful consideration of antibiotic choice 5.
Preoperative Screening and Treatment
- The routine screening and treatment of ASB in preoperative patients may not be necessary, as it may not reduce the risk of postoperative symptomatic UTIs 2, 3.
- However, in certain cases, such as pregnant women or patients undergoing urologic surgical procedures, preoperative screening and treatment of ASB may be recommended 4, 3.