Predictors of ertapenem therapeutic efficacy in the treatment of urinary tract infections (UTIs) in hospitalized adults: the importance of renal insufficiency and urinary pH.

In hospitalized adults acute uncomplicated cystitis (AUC) and catheter associated bacteriuria (CAB) may be treated with oral antibiotics. With AUC or CAB due to extended spectrum ß-lactamase (ESBL) + Gram negative bacilli (GNB) physicians often use intravenous therapy, e.g., ertapenem. We reviewed our recent experience in hospitalized adults with AUC and CAB treated with ertapenem. Therapeutic efficacy of ertapenem was assessed by decreased pyuria/bacteriuria, and elimination of the uropathogen. The effectiveness of ertapenem in the presence of renal insufficiency (CrCl < 50 ml/min) and acid and alkaline urinary pH were evaluated. In addition, rapidity of eradication of bacteriuria was assessed by time to negative urine cultures (TTNC). In those with an acid urinary pH ertapenem was highly effective in eliminating bacteriuria (TTNC < 3 days). TTNC was prolonged ( >3 days) in patients with decreased renal function and alkaline urinary pH. We reviewed 45 hospitalized adults with AUC or CAB to determine if renal insufficiency and or alkaline urinary pH affected ertapenem efficacy. In the 33 adult hospitalized patients with AUC and 12 with CAB, we found that ertapenem was consistently effective in eliminating the GNB bacteriuria. In hospitalized adults, the presence of renal insufficiency and acid urine, bacteriuria was eliminated in < 3 days. However, in those with renal insufficiency and an alkaline urine pH, the rapidity of cure, i.e., time to negative cultures (TTNC) was prolonged, i.e., > 3 days which has not been previously reported.