Sensitivity Study Of Aminoglycosides In Ocular Samples. Would Be It Useful To Recover Classic Antibiotics For The Treatment Of Current Infections?
Published 2025 - 43rd Congress of the ESCRS
Reference: PO924 | Type: Poster | DOI: 10.82333/anbt-q938
Authors: Ana Señaris Señaris-González* 1 , Javier Fernández 2 , María Fernández-García 1 , Maria Soledad Zapico 2 , Marta Alvarez-Coronado 1 , Begoña Baamonde-Arbaiza 1 , Enrique García-Carús 2
1Ophthalmology,Hospital Universitario Central de Asturias,Oviedo,Spain, 2Microbiology,Hospital Universitario Central de Asturias,Oviedo,Spain
Purpose
To present a study of sensitivity to aminoglycosides in ocular infections of bacterial origin
Setting
Ocular and ear infections of bacterial origin are treated using topical formulations of
antibiotics, the most used are aminoglycosides (gentamicin and tobramycin) and
fluoroquinolones. However, the increase in resistance raises the need to recover
classic antibiotics such as neltimycin.
Methods
Representative samples of ocular and otic infections were collected between July and November of 2024 in a tertiary hospital. Subsequently, a sensitivity study to aminoglycosides was carried out. The sensitivity to gentamicin and tobramycin was performed using gradient diffusion strips and sensitivity to neltimycin by disk plate (30 µg). The cut-off points of sensitivity used for topical gentamicin and tobramycin were those of the EUCAST, in the case of Staphylococcus aureus and enterobacteria of 2 mg/L for gentamicin and tobramycin, and for Pseudomonas aerguinosa of 8 and 2 mg/L respectively. For neltimycin, since there was no EUCAST breakpoint, the referred by CLSI, considering sensitive diameters ≥15mm and resistant ≤12mm.
Results
100 isolates were obtained. The microorganisms in order of frequency of isolation were Staphylococcus (50%), Enterobacteria (19%), P. aeruginosa (16%), Streptococcus (8%) and others (7%). Within the isolates of Staphylococcus, the most frecuent was S. aureus (70%). The overall sensitivity to gentamicin and tobramycin was 83% and 79%, respectively. Regarding coagulase-negative staphylococci, 73.3% were sensitive to gentamicin and 60% to tobramycin. In enterobacteria, the 100% isolates were sensitive to gentamicin and tobramycin; 93.7% P. aeruginosa isolates were sensitive to tobramycin while onl 53.3% to gentamicin. Regarding the results of sensitivity to neltimycin, 98% of the
isolates were sensitive and only 2 resistant isolates were found.
Conclusions
Aminoglycosides show activity against most isolates, although it is necessary to
select the appropriate molecule based on the etiology and the appearance of resistance could
limit the efficacy of these drugs.
Neltimycin showed activity against almost all isolates, therefore, this fact,
together with the clinical efficacy demonstrated in other studies could make it a superior option to
other aminoglycosides in the topical treatment of bacterial infections at the ophthalmic level
at present.