High Fosfomycin Susceptibility in Escherichia Coli Recovered from Urine in Brazil

Urinary Tract Infections (UTIs) are widespread globally, with a notably higher incidence in women. In 2018, the European Medicines Agency (EMA) endorsed the use of fluoroquinolones for uncomplicated UTI treatment. Following this recommendation, several international agencies adopted similar guidelines. Consequently, older antimicrobial agents like fosfomycin emerged as primary treatment options for UTIs. In this context, our study aimed to evaluate the susceptibility of Escherichia coli strains from urine samples to various recommended UTI antibiotics. These strains were collected between January 2017 and July 2020 in São Paulo, Brazil. We utilized the disk-diffusion method for antimicrobial susceptibility testing, interpreting the results according to BRCAST/EUCAST guidelines. Out of the 86,957 urine cultures undertaken during this timeframe, 10,041 yielded E. coli isolates. Of these, 8,655 were tested against fosfomycin, with 99.0% (8,572 strains) found to be susceptible. Additionally, susceptibility rates for other drugs were as follows: nitrofurantoin (95.8%), amoxicillin/clavulanic acid (83.9%), ciprofloxacin (65.1%), norfloxacin (65.6%), and levofloxacin (67.7%). Notably, of the 571 ESBL-positive strains, 94.0% were susceptible to fosfomycin. It’s important to mention a slight decline in fosfomycin susceptibility observed during this period. This finding underscores the importance of continuous monitoring for fosfomycin resistance and rational usage of the drug.