[Resistance testing for urinary tract infections. A barrier to guideline implementation]

Urinary tract infections (UTI) are among the most common reasons for antibiotic prescriptions. Due to increasing resistance rates, antibiotic therapy should be targeted and based on evidence-based recommendations. Test results and recommendations by medical laboratories have a relevant impact on the choice of antibiotics. The extent to which medical laboratories consider antibiotics recommended by evidence-based treatment guidelines in microbiological testing is unclear.

The aim of the present study is to assess whether guideline recommendations for antibiotic therapy of UTI are taken into account by medical laboratories in northern Germany.

A standardized and piloted questionnaire was used in our telephone survey. All microbiological laboratories in northern Germany (Hamburg, Bremen, Lower Saxony, Schleswig-Holstein, and Mecklenburg-Western Pomerania; n = 82) were asked about their standards in diagnosing and microbiological testing of urine cultures.

A total of 71 of the 82 contacted laboratories perform microbiological tests, whereby 40 of these participated (56 %). Most of the laboratories (43 %) routinely perform microbiological testing when bacterial counts were ≥ 10(4) colony forming units per ml (CFU/ml), 15 % ≥ 10(5) CFU/ml, 17 % ≥ 10(3) CFU/ml, and 8 % ≥ 10(2) CFU/ml. Antibiotic testing includes ciprofloxacin (95 %), cotrimoxazole (87.5 %), trimethoprim (57 %), fosfomycin (85 %), and nitrofurantoin (72 %).

The diagnostic threshold recommended in evidence-based guidelines (10(3) CFU/ml) is used only by a few laboratories. Antibiotics recommended as a first line therapy are only partly taken into account in microbiological testing. This variance in different diagnostic thresholds and microbiological testing is a barrier to guideline implementation.