Etiology and sensitivity of uropathogens identified in uncomplicated lower urinary tract infections in women (ARESC Study): implications on empiric therapy

To determine the etiology and susceptibility of uropathogens identified in women with uncomplicated lower urinary tract infections (UTI). In a multicenter study (ARESC) in 9 Spanish hospitals, 803 female patients with uncomplicated cystitis were consecutively enrolled and evaluated to identify the uropathogens and their susceptibility to 9 antimicrobials. Of 803 patients with uncomplicated cystitis, 784 patients were included. A positive urine culture was found in 87.7% of the samples. Of the 650 pathogens isolated, Escherichia coli (E. coli) was the most frequent (79.2%) followed by Staphylococcus saprophyticus (4.4%), Proteus mirabilis (4.3%), Enterococcus faecalis (3.2%) and Klebsiella pneumoniae (2.3%). E. coli showed a high rate of susceptibility to phosphomycin (97.2%), nitrofurantoin (94.1%) and somewhat lower to ciprofloxacin (88.1%). Fluorquinolone resistance rates were higher among postmenopausal women (17 versus 10%). E. coli was highly resistant to ampicillin (65%) and cotrimoxazole (34%) and 25% of the strains were resistant to amoxicillin/clavulanalic acid and cefuroxime. In Spain, E. coli shows high resistance rates to widely used antimicrobial antibiotics. Phosphomycin and nitrofurantoin have a high in vitro activity. Taking into account practical aspects such as convenience (only one dose), and the influence of the amount of fluorquinolone use on enterobacteriaceae and other microorganisms resistance levels, phosphomycin trometamol represents the option of first choice for the empirical treatment of uncomplicated cystitis in women.