Research Article

The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections

Volume: 79 Number: 1 March 27, 2026
Elif Nur Özbay Haliloğlu *, Güle Çınar , Kemal Osman Memikoğlu
TR EN

The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections

Abstract

Background: Antimicrobial resistance in Gram-negative bacteria especially infections due to multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan drug-resistant (PDR) strains has narrowed therapeutic options. In the absence of many new agents, older antibiotics are being reconsidered in combination regimens. Fosfomycin, with a unique mechanism and broad spectrum, is a leading candidate in this context. Objective: To assess whether parenteral fosfomycin-based combinations influence mortality and morbidity in hospitalized adults with MDR/XDR/PDR Gramnegative infections. Methods: We conducted a retrospective study of adults treated between February 2019 and June 2020 in university hospital ICUs and wards. Patients received either combination therapy including IV fosfomycin (n=141) or combination therapy without fosfomycin (n=137). Demographic, clinical, laboratory and treatment data were extracted from the hospital information system. Results: Baseline age, sex, APACHE II and SOFA scores were similar between groups, whereas the fosfomycin group had a higher Charlson comorbidity index. No significant difference was observed in 28-day or 60-day mortality between fosfomycin and control groups (p=0.568 and p=0.094, respectively); point estimates favored the fosfomycin group (28-day mortality 41.1% vs 44.5%). Mortality correlated with higher illness severity and invasive device use in both groups. Ten patients receiving fosfomycin developed hypernatremia. Conclusion: In patients with high illness severity, comorbidity, and invasive device needs, fosfomycin-containing combinations, when used with suitable companion agents and accompanied by careful safety monitoring, constitute a rational treatment option against MDR/XDR/PDR Gram-negative infections. Pharmacokinetic (PK) and pharmacodynamic (PD) data and well-designed clinical studies are required to clarify clinical efficacy and safety.

Keywords

Multidrug resistant, extremely drug resistant, pan drug resistant, fosfomycin

References

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APA
Özbay Haliloğlu, E. N., Çınar, G., & Memikoğlu, K. O. (2026). The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections. Ankara Üniversitesi Tıp Fakültesi Mecmuası, 79(1), 72-81. https://doi.org/10.65092/autfm.1779034
AMA
1.Özbay Haliloğlu EN, Çınar G, Memikoğlu KO. The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections. Ankara Üniversitesi Tıp Fakültesi Mecmuası. 2026;79(1):72-81. doi:10.65092/autfm.1779034
Chicago
Özbay Haliloğlu, Elif Nur, Güle Çınar, and Kemal Osman Memikoğlu. 2026. “The Efficacy of Antibiotic Combination Therapies With Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections”. Ankara Üniversitesi Tıp Fakültesi Mecmuası 79 (1): 72-81. https://doi.org/10.65092/autfm.1779034.
EndNote
Özbay Haliloğlu EN, Çınar G, Memikoğlu KO (March 1, 2026) The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections. Ankara Üniversitesi Tıp Fakültesi Mecmuası 79 1 72–81.
IEEE
[1]E. N. Özbay Haliloğlu, G. Çınar, and K. O. Memikoğlu, “The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections”, Ankara Üniversitesi Tıp Fakültesi Mecmuası, vol. 79, no. 1, pp. 72–81, Mar. 2026, doi: 10.65092/autfm.1779034.
ISNAD
Özbay Haliloğlu, Elif Nur - Çınar, Güle - Memikoğlu, Kemal Osman. “The Efficacy of Antibiotic Combination Therapies With Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections”. Ankara Üniversitesi Tıp Fakültesi Mecmuası 79/1 (March 1, 2026): 72-81. https://doi.org/10.65092/autfm.1779034.
JAMA
1.Özbay Haliloğlu EN, Çınar G, Memikoğlu KO. The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections. Ankara Üniversitesi Tıp Fakültesi Mecmuası. 2026;79:72–81.
MLA
Özbay Haliloğlu, Elif Nur, et al. “The Efficacy of Antibiotic Combination Therapies With Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections”. Ankara Üniversitesi Tıp Fakültesi Mecmuası, vol. 79, no. 1, Mar. 2026, pp. 72-81, doi:10.65092/autfm.1779034.
Vancouver
1.Elif Nur Özbay Haliloğlu, Güle Çınar, Kemal Osman Memikoğlu. The Efficacy of Antibiotic Combination Therapies with Fosfomycin For Multi-Drug Resistant Gram-Negative Bacterial Infections. Ankara Üniversitesi Tıp Fakültesi Mecmuası. 2026 Mar. 1;79(1):72-81. doi:10.65092/autfm.1779034