ARESC study - a prospective international multicenter study on the antibiotic resistance of cystitis pathogens

ARESC (Antimicrobial Resistance Epidemiological Survey on Cystitis) is a prospective international multicenter study on the prevalence and resistance to antibiotics of pathogens of cystitis.

During 2003-2006 in 74 medical centers in 10 countries (Germany, Italy, France, Spain, USA, Brazil, Poland, Hungary, Australia, Holland), the ARESC study selected, identified and determined the sensitivity of uropathogens to 9 antimicrobials in adult patients (n = 4,264) aged 18 to 65 with symptoms of uncomplicated cystitis. In the USA, 8 centers from the European part of USA participated in the study.

The most common causative agent of uncomplicated urinary tract infections was Escherichia coli (76.7% of all selected microorganisms). Among the strains of E. Coli, 10.3% of the isolates were resistant to at least three different classes of antimicrobial agents. The most common were resistance to ampicillin (48.3%), trimethoprim / sulfamethoxazole (29.4%) and nalidixic acid (18.6%). The most active drugs against E. coli were phosphomycin, mecillin and nitrofurantoin (98.1%, 95.8% and 95.2% of susceptible strains, respectively), as well as ciprofloxacin, amoxicillin / clavulanate and cefuroxime (91.7%, 82.5% and 82.4%, respectively).

In Brazil, USA, Spain and Italy, the level of resistance of uropathogens to ciprofloxacin has exceeded 10%. Proteus mirabilis was more sensitive to β-lactams and less sensitive to non-β-lactam antibiotics than E. coli, while the Klebsiella pneumoniae strains resistant to ampicillin were less susceptible to mecillinam (88.8%), phosphomycin (87.9%), cefuroxime (78.6%) and nitrofurantoin (17.7%). The Staphylococcus saprophyticus strains showed resistance to ampicillin (36.4%) and trimethoprim / sulfamethoxazole (10.2%). In Italy, Spain, Brazil and USA (the countries where antibiotic resistance is most widespread), 48 strains of uropathogens (39 isolates of E. coli, 6 - K. pneumoniae and 3 - P. mirabilis) produced extended spectrum β-lactamases (BLRS), most of which were CTX-M.

Thus, despite the differences between countries in the sensitivity of uropathogens which cause uncomplicated cystitis, phosphomycin and mecillins remain in vitro active against most of the pathogenic cystitis identified in all the countries participating in the ARESC study.