The Influence of Urinary pH on Antibiotic Efficacy Against Bacterial Uropathogens

Objective To determine the effects of pH on the activity of clinically relevant antibiotics against bacterial uropathogens. Numerous factors affect antibiotic efficacy within the urinary tract including pH. Because human urine can substantially vary from acidic (pH 4.5) to alkaline (pH 8) conditions and can be easily clinically manipulated, it would be a great advantage to better understand the role of pH in antibiotic treatment of urinary tract infection. Materials and Methods This in vitro study investigated the activity of 24 widely used antimicrobial agents against bacterial strains comprising 6 major uropathogenic species ( Escherichia coli , Klebsiella pneumoniae , Proteus mirabilis , Enterococcus faecalis , Staphylococcus saprophyticus , and Staphylococcus epidermidis ) over the range of pH 5-8. Standard disk-diffusion and broth-microdilution assays were used. One-way analysis of variance was applied to determine significance ( P