[In vitro activity of fosfomycin, alone or in combination, against clinical isolates of carbapenem resistant Pseudomonas aeruginosa].
BACKGROUND
The increase in microorganisms showing patterns of multi-drug resistance or even pan-drug resistance is of growing concern. Fosfomycin (FO) is well known to be active against a wide variety of microorganisms, including highly resistant strains of Pseudomonas aeruginosa (P. aeruginosa), and can also synergistically act with other molecules.


METHODS
This study examines the in vitro activity shown by FO against 120 strains of carbapenem-resistant P. aeruginosa using an agar dilution and a gradient diffusion test. Possible synergistic effects of the combinations of FO/amikacin and FO/ciprofloxacin were also examined using E-test and time-kill techniques.


RESULTS
According to the epidemiological cut-off value (ECOFF) issued by the European Committee on Antimicrobial Susceptibility Testing (EUCAST), our results indicate that over three-quarters of the strains tested would be susceptible to FO treatment, especially if combined with another antimicrobial. The FO/ciprofloxacin combination had a synergistic effect on 40% of the clinical isolates, while for FO/amikacin this effect was only observed in 12% of the isolates.


CONCLUSIONS
The appearance of carbapenem-resistant P. aeruginosa strains requires the evaluation by combination therapy. This report suggests that the FO/ciprofloxacin combination can be useful, showing a synergistic effect in 40% of the isolates.
Servicio de Microbiología, Hospital de Móstoles, Móstoles, Madrid, España. Electronic address: jlgarces@microb.net.
José-Luis
JL
Gómez-Garcés
Servicio de Microbiología, Hospital de Móstoles, Móstoles, Madrid, España.
Yolanda
Y
Gil-Romero
Servicio de Microbiología, Hospital de Móstoles, Móstoles, Madrid, España.
Nuria
N
Sanz-Rodríguez
Servicio de Microbiología, Hospital de Móstoles, Móstoles, Madrid, España.
Carmen
C
Muñoz-Paraíso
Servicio de Microbiología, Hospital de Móstoles, Móstoles, Madrid, España.
Marta
M
Regodón-Domínguez
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004357:Drug Synergism; D005578:Fosfomycin / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D015780:Carbapenems; D005578:Fosfomycin; D002939:Ciprofloxacin
Efecto sinérgico; Fosfomicina; Fosfomycin; Pseudomonas aeruginosa; Synergistic effect