Susceptibility of contemporary isolates to fosfomycin: a systematic review of the literature

The aim of this review was to evaluate the susceptibility of contemporary Gram-positive and Gram-negative bacteria to fosfomycin. PubMed and Scopus databases were systematically searched to identify studies published in print or electronically from January 2010 until June 2015. In total, 84 studies were selected. Susceptibility to fosfomycin of Staphylococcus aureus ranged between 33.2% and 100% (frequency = 91.7%, 95% confidence interval 88.7-94.9%), of Enterococcus spp. from 30% to 100% (Enterococcus faecium 92.6%, 85.2-100%; Enterococcus faecalis 96.8%, 92.5-100%), of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli from 81% to 100% (95.1%, 94.3-95.9%), of ESBL-producing Klebsiella pneumoniae from 15% to 100% (83.8%, 78.7-89.4%) and of carbapenem-resistant (CR) K. pneumoniae from 39.2% to 100% (73.5%, 66.4-81.4%). Staphylococcus aureus (including meticillin-resistant strains) and E. coli (including ESBL-producing strains) were the most likely to be susceptible with low minimum inhibitory concentrations (MICs). Enterococci (particularly vancomycin-resistant E. faecium) and K. pneumoniae (especially CR strains) were less susceptible with higher MIC50 and MIC90 values. Two studies reported decreasing susceptibility of ESBL-producing E. coli to fosfomycin. In conclusion, guided by local susceptibility data, fosfomycin could be considered for the treatment of patients with infections due to problematic multidrug-resistant bacteria.