Posters

Bacteriological profile of coagulase-negative staphylococci isolated from endophthalmitis

Poster Details

First Author: T.Torikai JAPAN

Co Author(s):    T. Suzuki   T. Yamamoto   Y. Ohashi              

Abstract Details

Purpose:

Coagulase-negative staphylococci (CNS) is a major causative pathogen of endophthalmitis after cataract surgery. Its origin may be external eye such as conjunctival sac and eye lid, and commensal CNS may contaminate to eye during surgery and cause endophthalmitis. In order to prevent endophthalmitis, it is important to know the characteristics of isolates from endophthalmitis. This study was conducted to examine bacteriological profile of CNS isolated from endophthalmitis as follows: identification of CNS, antibiotic susceptibility, ability of biofilm formation, and genetic diversity among isolates.

Setting:

Department of Ophthalmology, Ehime University, Graduate School of Medicine

Methods:

Twelve CNS isolates from aqueous or vitreous humor in patients with endophthalmitis after cataract surgery were studied. To identify the isolates, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) was performed. The antibiotic activity of each drug was determined by an agar dilution method. Biofilm formation was checked using microtiter plate assay. The isolates were typed using the DiversiLab typing system (DL), which uses the presence of DNA repetitive elements present in the organism's genome to determine the genetic relatedness of bacterial isolates.

Results:

Analysis using MALDI-TOF MS identified 9 Staphylococcus epidermidis, 2 S. hominis, and one S. warneri isolate. All CNS isolates showed resistance to methicillin and ceftazidime, and 10 isolates were resistance to levofloxacin. All isolates showed susceptibility to vancomycin, linezolid, and minocycline. Biofilm ability was found in all isolates. DL demonstrated that two pair of S. epidermidis isolates had similarity with more than 95%.

Conclusions:

S. epidermidis was predominant in CNS causing endophthalmitis, and resistance of cephalosporin and fluoroquinolone was found frequently in isolates. Moreover all isolates could produce biofilm, and genetic diversity among isolates could be small. Preoperative antibiotics such as fluoroquinolone could eradicate antibiotic sensitive CNS and prevent endophthalmitis, however it could select antibiotic resistant and biofilm producing CNS, and they could cause endophthalmitis. We need to consider regularly choice of antibiotics for prevention of endophthalmitis and make not to increase drug resistant bacteria.

Financial Disclosure:

One or more of the authors research is funded, fully or partially, by a company producing, developing or supplying the product or procedure presented