Posters

Identification and antimicrobial susceptibility of microorganisms isolated from corneal ulcers: an 3-year review in a tertiary hospital

Poster Details

First Author: S.Parreira PORTUGAL

Co Author(s): D. Lopes   S. Barros   F. Freitas   J. Diogo   N. Campos        

Abstract Details

Purpose:

Corneal ulcer is a serious vision threatening inflammation that may even lead to the loss of an eye. The initial therapy usually requires broad spectrum antibiotics but their reckless use in everyday practice has lead either to treatment failure or to the development of resistant bacteria that make ophthalmic infection quite challenging to treat. The aim of this study was to investigate which microorganisms are most frequently found in patients with corneal ulcers and determine the susceptibility to antibiotics most frequently used in the clinic.

Setting:

This is a retrospective study. All of study case were taken in Department of Ophthalmology and Microbiology Laboratory at Hospital Garcia de Orta, Portugal.

Methods:

Corneal scrape results recorded by the microbiology service between 2014 and 2016 were extracted from an established database. Clinical specimens were obtained from each corneal ulcer by corneal scraping. The samples were placed directly into brain-heart-infusion (BHI) broth and transported to Microbiology Laboratory. Antimicrobial susceptibility test for isolated organisms was done using Agar disk diffusion method. The data were entered and analysed using SPSS software version 22 package.

Results:

A total of 83 smears were submitted for microbiological evaluation and 49 samples were positive by culture (59%). Mean age was 49 years. Eighteen (36,7%) patients had risk factors. A single organism was isolated in 44 specimens (89,8%), while five (10,2%) samples presented two or more different organisms. Of the microorganisms identified, 68,4% were Gram-negative bacteria, 27,6% Gram-positive bacteria and 4% fungi. Pseudomonas aeruginosa was the most frequently isolated genus (47%), followed by Staphylococcus aureus and Streptococcus pneumoniae (10,2%). Two antibiotics had high efficacy against the isolates: gentamicin (73,4%) and ciprofloxacin (71,4%). The macrolides class were effective only against 26,5%.

Conclusions:

The prevalence of bacterial infection among patients with corneal ulcers was high, when compared to other microorganisms such as fungi. The predominant isolates were gram-negative bacteria and most of the bacterial isolates were susceptible to gentamicin and ciprofloxacin constituting a plausible choice in the initial treatment of corneal ulcers. No significant increase in resistance was observed in vitro for any of the commonly used antibiotics. However, in order to prevent the rate of antimicrobial resistance, it´s important the identification of bacteria through culture methods and conducting drug susceptibility test as a routine diagnostic procedure.

Financial Disclosure:

None