The use of fosfomycin in infections caused by multidrug-resistant pathogens, especially pneumonia in children: a five-year retrospective single-centre experience.

Background: Fosfomycin is gaining increasing attention for its activity against MDR or XDR pathogens. Currently, IV fosfomycin is a potential option for treating various infections, including urinary tract infections, pneumonia and skin infections when first-line treatments fail.

Objectives: To evaluate the demographic, clinical, microbiological and treatment modality of children received IV fosfomycin to treat infections caused by MDR pathogens since there are few data on the use of fosfomycin in children.

Methods: This study was conducted retrospectively with patients under 18 years of age who were treated with IV fosfomycin for at least 72 h due to infections caused by MDR pathogens between January 2019 and October 2023 at Marmara University Pendik Training and Research Hospital, İstanbul, Türkiye. Data on demographic and clinical features, microbiological findings, treatment modalities and side effects were evaluated.

Results: Twenty-five children, for a total of 32 cases of infection episodes, with a mean age of 11.4 ± 3.92 years who received IV fosfomycin were included. The most frequent comorbidity was chronic pulmonary diseases, and the most common infection needed for IV fosfomycin was MDR Pseudomonas aeruginosa pneumonia. In all cases, fosfomycin was administered in combination with other antibiotics, mainly meropenem-colistin (68.7%) or meropenem (15.6%). Twenty-two (71.9%) cases had favourable clinical responses at the end of therapy.

Conclusions: Our results suggest that IV fosfomycin may be an effective treatment option for MDR pathogens in the paediatric population. Nevertheless, careful stewardship is necessary to maintain efficacy and reduce antimicrobial resistance selection risk.