Download ARVO 2014 Annual Meeting Abstracts 516 Antimicrobials Thursday

ARVO 2014 Annual Meeting Abstracts
516 Antimicrobials
Thursday, May 08, 2014 8:30 AM–10:15 AM
Exhibit/Poster Hall SA Poster Session
Program #/Board # Range: 5783–5792/B0208–B0217
Organizing Section: Physiology/Pharmacology
Program Number: 5783 Poster Board Number: B0208
Presentation Time: 8:30 AM–10:15 AM
INNOVATIVE AQUEOUS AZITHROMYCIN OPHTHALMIC
FORMULATION
Maria G. Saita, Danilo Aleo, Sergio Mangiafico, Barbara Melilli,
Melina G. Cro, Sebastiano Mangiafico. R&D, Medivis, Catania,
Italy.
Purpose: Azithromycin (AZM) is a semi-synthetic macrolide
antibiotic largely employed as topical formulation to cure ocular
surface infections. Unfortunately, AZM is unstable and practically
insoluble in water. In fact, commercial formulations of AZM stable at
room temperature are available only in oily vehicle, if a water vehicle
is employed the product has to be refrigerated. Our aim was to
develop an aqueous mucoadhesive AZM formulation stable at room
temperature.
Methods: The new formulation of AZM (MDV 1226) was prepared
by adding 1.5% of AZM dihydrate, in a solution of appropriate
cyclodextrin, to an isosmolar buffer solution (pH=6.7-7.2). The
mucoadhesive Hyaluronic Acid was added to improve precorneal
residence time of MDV 1226 on the ocular surface. Stability studies
were performed under different ICH recommended conditions at
25°C and 40°C. Concentrations (%) of AZM (evaluated by HPLC),
pH and Osmolality of the formulation were controlled for 12 months.
Moreover a comparative stress thermal study at 70°C was conducted
in comparison to commercial topical aqueous formulation of
Azithromycin (Azasite).
Results: Stability study conducted at 70°C showed that AZM
in MDV 1226 was more stable than AZM in Azasite: after 2
weeks concentration of AZM in the two formulations was 70% in
MDV 1226 and only 17% in Azasite. Stability study under ICH
recommended conditions showed that AZM in MDV1226 at 25°C
was 99% after 12 months and 80% at 40°C after 6 months. The
main degradation pattern of AZM was elucidated by HPLC-MS
and concerns the hydrolysis of sugar at C-3 (L-Cladinose) of AZM
lactone to conduct at descladinose azithromycin (DAZM). Osmolality
and pH in MDV 1226 were maintained stable for 12 months.
Conclusions: Stability studies showed that no significant changes
were observed with respect to pH, Osmolality and concentration
of AZM in MDV 1226 for 12 months at room temperature. The
presence of the mucoadhesive Hyaluronic Acid in MDV 1226 should
guarantee better performance of the topical AZM. Pharmacokinetics
studies in rabbits are on going.
Commercial Relationships: Maria G. Saita, Medivis (E); Danilo
Aleo, Medivis (E); Sergio Mangiafico, Medivis (E); Barbara
Melilli, Medivis (E); Melina G. Cro, Medivis (E); Sebastiano
Mangiafico, Medivis (E)
Program Number: 5784 Poster Board Number: B0209
Presentation Time: 8:30 AM–10:15 AM
Correlation of Phenotypic Expression of Methicillin Resistance
with Genotype and In Vitro Susceptibility for mecA+
Staphylococcus epidermidis Endophthalmitis Isolates
Laura C. Huang1, Jack Stringham2, James Wong1, Jorge Maestre2,
Darlene Miller2, Harry W. Flynn2. 1University of Miami Miller
School of Medicine, Miami, FL; 2Bascom Palmer Eye Institute,
Miami, FL.
Purpose: To correlate the genotypic methicillin resistance conferred
by the mecA gene with phenotypic expression of methicillin
resistance among Staphylococcus (S) epidermidis isolates from
endophthalmitis and in vitro susceptibility to ceftaroline, a new fifth
generation cephalosporin, and other commonly used antimicrobials.
Methods: Etests and the VITEK 2 system were used to detect the
presence and phenotypic expression of methicillin resistance among
S. epidermidis isolates recovered from endophthalmitis. Results were
compared with mecA genotype using polymerase chain reaction
(PCR) and in vitro susceptibility to ceftaroline and vancomycin
(Etests) and VITEK 2 breakpoints for gentamicin, daptomycin,
linezolid, tigecycline, levofloxacin, and moxifloxacin. Additionally,
antibiotic susceptibility was analyzed against the following
subgroups: mecA+ with methicillin resistance (group A) and isolates
that were mecA+ though clinically methicillin sensitive (group B).
Results: All 32 isolates recovered from 2010-2013 were mecAgenotype positive (100%), however, only 21/32 (65.6%) expressed
methicillin resistance by conventional laboratory tests. Isolates
were 100% susceptible to vancomycin (MIC90 3 μg/mL, N=32),
ceftaroline (MIC90 0.38 μg/mL, N=32), linezolid (N=20), and
tigecycline (N=20). The susceptibility of daptomycin (N=20) was
95%. Gentamicin susceptibility overall was 86.7% (26/30) of which
group A had 78.9% (15/19) susceptible compared to 100% (11/11)
in group B. A correlation between the phenotypic expression of
mecA genotype and in vitro susceptibility was demonstrated for
the fluoroquinolones. For levofloxacin, group A had 21.1% (4/19)
susceptible in contrast to 81.8% (9/11) (p=0.001) in group B. For
moxifloxacin, group A had 30% (3/10) susceptible compared to 80%
(8/10) (p=0.025) in group B.
Conclusions: Routine laboratory methods may fail to detect
heterogeneous and or low level expression of methicillin resistance
among mecA+ S. epidermidis genotypes. This may have important
implications for the correct selection and management of S.
epidermidis endophthalmitis. The new fifth generation cephalosporin,
ceftaroline, demonstrated low MIC values and may show promise as
a therapeutic agent for methicillin resistant S. epidermidis.
Commercial Relationships: Laura C. Huang, None; Jack
Stringham, None; James Wong, None; Jorge Maestre, None;
Darlene Miller, None; Harry W. Flynn, None
Support: NIH Center Core Grant P30EY014801, Research to
Prevent Blindness Unrestricted Grant, Department of Defense (DODGrant#W81XWH-09-1-0675).
Program Number: 5785 Poster Board Number: B0210
Presentation Time: 8:30 AM–10:15 AM
Bactericidal Activity of Levofloxacin against Staphylococcus
aureus and Staphylococcus epidermidis in an In Vitro
Pharmacokinetic Model Simulating Concentration in the Bulbar
Conjunctiva after Eye Drop
Takashi Suzuki, Toshihiro Yamamoto, Yuichi Ohashi. Ophthalmology,
Ehime University School of Medicine, Toon, Japan.
Purpose: The aim of this work was to compare the pharmacological
properties of levofloxacin (LVFX) against Staphylococcus aureus
and Staphylococcus epidermidis by pharmacokinetic (PK) model
simulating concentration in the bulbar conjunctiva after eye drop of
0.5% and 1.5% LVFX.
Methods: The strains used were S. aureus and S. epidermidis
conjunctival sac isolates which minimum inhibitory concentrations
(MICs) of LVFX were 0.25 and 0.125 μg/ml, respectively. The LVFX
resistant strains were made from their parental strains by culture
with LVFX. The in vitro PK model simulated the concentration of
the bulbar conjunctiva following topical application of 0.5 or 1.5%
LVFX ophthalmic solution three times (0, 4 and 8 hour) to rabbit
©2014, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at [email protected].
ARVO 2014 Annual Meeting Abstracts
eyes. Parental and LVFX resistant strains were exposed to LVFX in
an in vitro PK model, and changes in viable bacterial counts were
evaluated over the course of 12h.
Results: MICs of LVFX in resistant isolates increased from 2 to 32
times of parental strains (S. aureus; 0.5-2μg/ml, S. epidermidis; 0.54μg/ml) after induction of LVFX resistance. LVFX was bactericidal
against all tested strains which MICs included highest value, in PK
model simulating use of 1.5% LVFX ophthalmic solution. In contrast,
simulation of 0.5% LVFX eye drop showed LVFX was bactericidal
against isolates which MICs were as follows: (S. aureus; 0.25-0.5μg/
ml, S. epidermidis; 0.125-1μg/ml).
Conclusions: In vitro PK model simulating concentration in
the bulbar conjunctiva after LVFX eye drop demonstrated 1.5%
LVFX ophthalmic solution had stronger bactericidal effects against
Staphylococci in the bulbar conjunctiva than 0.5% LVFX ophthalmic
solution.
Commercial Relationships: Takashi Suzuki, Santen Pharmaceutical
Co., Ltd (F); Toshihiro Yamamoto, Santen Pharmaceutical Co., Ltd
(F); Yuichi Ohashi, Santen Pharmaceutical Co., Ltd (F)
Support: This was collaborative research with Santen
Pharmaceutical Co., Ltd.
Program Number: 5786 Poster Board Number: B0211
Presentation Time: 8:30 AM–10:15 AM
Cytotoxicity of Ophthalmic Antimicrobial Solutions on SV40immortalized Human Corneal Epithelial Cells
Jae Lim Chung1, Young A Kwon1, Sang Wroul Song1, Byung
Yeop Kim1, Joon H. Lee1, Kyoung Yul Seo2, Christopher Ta3.
1
Ophthalmology, Myung-Gok Eye Research Institute, Kim’s
Eye Hospital, Konyang University College of Medicine, Seoul,
Republic of Korea; 2Ophthalmology, Institute of Vision Research,
Yonsei University College of Medicine, Seoul, Republic of Korea;
3
Ophthalmology, Byers Eye Institute, Stanford University School of
Medicine, Palo Alto, CA.
Purpose: To enhance the pharmacokinetic properties of ophthalmic
antimicrobials, high-concentration of active ingredient or surfaceretentive delivery system are being used. However, ocular toxicity
is a concern when using these agents. In this study, we evaluated the
cytotoxicity of various ophthalmic antibiotics on SV40-immortalized
human corneal epithelial cells using the 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium
(MTS) assay.
Methods: We tested original and 10-fold diluted solutions of
Cravit (levofloxacin 0.5%), Cravit 1.5 (levofloxacin 1.5%), Quixin
(levofloxacin 0.5%, Benzalkonium chloride (BAK) 0.005%),
Iquix (levofloxacin 1.5%), Vigamox (moxifloxacin 0.5%), Moxeza
(moxifloxacin 0.5%, xanthan gum), Gatiflo (gatifloxacin 0.3%),
Zymaxid (gatifloxacin 0.5%, BAK 0.005%), Besivance (besifloxacin,
BAK 0.01%, durasite), Azasite (azithromycin 1%, BAK 0.003%,
durasite), Tobrex (tobramycin 0.3%, BAK 0.01%). We also tested
using standard material powders of each drug to rule out the effect
of other components in ophthalmic solutions. The MTS assay was
performed after 5 to 120 minutes of exposure to each solution.
According to the cell survival score, we graded the cytotoxicity as
mild(over 75%), moderate(50~75%) and marked(below 50%).
Results: Following exposure to undiluted solutions, cell viabilities
were decreased to 9~73% after 5 minutes. After 30 minutes Tobrex,
Zymaxid and Quixin showed marked toxicity, Cravit 1.5, Iquix
and Vigamox showed moderate toxicity and Cravit and Gatiflo
showed mild toxicity. When exposed to 10-fold diluted solutions,
Tobrex, Besivance, Zymaxid, Quixin and Azasite, which were BAK
containing products, showed moderate toxicity. After exposure to
standard powder solutions, 0.6% besifloxacin, 0.5% gatifloxacin,
0.5% moxifloxacin, 1.5% levofloxacin and 0.5% levofloxacin showed
moderate toxicity in decreasing order. However, 1% azithromycin
and 0.3% tobramycin standard powder solutions showed the least
toxicity.
Conclusions: High concentration alone did not further increase
cytotoxicity. The most important factor for the determination of
cytotoxicity was the concentration of BAK in antimicrobial solutions.
Commercial Relationships: Jae Lim Chung, None; Young A
Kwon, None; Sang Wroul Song, None; Byung Yeop Kim, None;
Joon H. Lee, None; Kyoung Yul Seo, None; Christopher Ta, None
Program Number: 5787 Poster Board Number: B0212
Presentation Time: 8:30 AM–10:15 AM
5% Betadine solution in not effective in inhibiting the growth of
different Gram Negative and Gram Positive Pathogens in vitro
Eric Huynh1, Phat Tran1, 2, Patrick Pham1, Abdul Hamood2, Kelly
Mitchell1, Ted W. Reid1, 2. 1Ophthalmology and Visual Sciences, Texas
Tech Univ Health Sciences Ctr, Lubbock, TX; 2Immunology and
Molecular Microbiology, Texas Tech University Health Sciences Ctr,
Lubbock, TX.
Purpose: Injections of intravitreal medications has become
routine care in ophthalmology offices throughout the world for the
treatment of several retinal diseases. Studies estimate that the rate
of endophthalmitis form intraocular injections range from 1.67%
to 0.006%. Currently, 5% providone-iodine (Betadine) is widely
accepted as the main antisepsis used to decrease this risk. Thus, the
present study was undertaken to measure the effectiveness of 5%
Betadine in inhibiting the growth of both Gram negative and Gram
positive bacteria.
Methods: Betadine disks were prepared by adding 20 μl of 5%
Betadine solution onto each 6 mm diameter BBL blank paper disk.
LB Agar plates were inoculated with a confluent lawn of bacteria,
made on each plate using cotton swabs dipped into 107 CFU/ml
of the bacterial suspensions. Within 15 min after the plates were
inoculated, Betadine disks were distributed evenly onto the LB Agar
surface, with at least 24 mm (center to center) between them. The
plates were incubated at 37oC for 24 h before results were read. The
diameters of the zones of complete inhibition, including the diameter
of the disk, were measured to the nearest millimeter with a ruler. In
addition, the remaining microorganisms on the disks were quantified
by the CFU assay. All experiments were done in triplicate, and all
measurements were repeated three times. The bacteria tested were
Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter
baumannii, Escherichia coli, Streptococcus salivarius, Streptococcus
mutans, Staphylococcus epidermidis, and Serratia marcescens.
Results: All the bacteria, except Pseudomonas aeruginosa, showed
zones of inhibition against the lawns of bacteria. However, when the
disks were tested for bacteria after the zone of inhibition study was
completed, only three of the eight different bacteria showed killing
of the bacteria on the disk. These were, one gram negative bacteria,
Serratia marcescens, and two gram positive bacteria, Streptococcus
salivarius, and Streptococcus mutans.
Conclusions: The two main conclusions are: 1) the zone of inhibition
assay does not give a realistic assessment of the ability of an
antimicrobial to kill bacteria; and 2) In vitro, 5% Betadine does not
appear to be effective at killing the bacterial species associated with
post procedure endophthalmitis.
Commercial Relationships: Eric Huynh, None; Phat Tran, None;
Patrick Pham, None; Abdul Hamood, None; Kelly Mitchell, None;
Ted W. Reid, None
©2014, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at [email protected].
ARVO 2014 Annual Meeting Abstracts
Program Number: 5788 Poster Board Number: B0213
Presentation Time: 8:30 AM–10:15 AM
Effect of biguanide on excystment, proliferation and death of
Acanthamoeba strains
Marina Roizenblatt, Linda C. Carrijo-Carvalho, Annette S. Foronda,
Fabio R. Carvalho, Denise Freitas. Department of Ophthalmology
and Visual Sciences, Paulista School of Medicine, São Paulo
Hospital, Federal University of São Paulo, São Paulo, Brazil.
Purpose: Acanthamoeba keratitis is a sight-threating infection which
can progress into the eye, causing corneal ulcer, loss of visual acuity
and eventually blindness. There is a lack of a standard therapy.
The treatment is based on topical instillation of biguanides and/ or
diamidines at higher concentration and these compounds seems to be
toxic to corneal cells. The present study was designed to investigate
the antimicrobial activity of a biguanide, at a lower concentration,
against Acanthamoeba cysts isolated from a severe AK case,
comparing the susceptibility pattern with an avirulent strain of the
protozoa.
Methods: The study was approved by the local ethics committee.
The effect of polyhexamethylene biguanide (PHMB) at 0.02% was
evaluated in an avirulent Acanthamoeba strain (ATCC 30011) and
a clinical isolate. Induction of death, excystment and proliferation
of protozoa at 12 and 72 h were evaluated by quantitative analysis.
The experimental procedures were carried out in triplicate. Data
were subjected to one-way ANOVA and results were considered
statistically significant when p < 0.05.
Results: Our findings demonstrated a reduction of 44.5 and 61.6%
in the total number of trophozoites from ATCC 30011 and clinical
isolate, respectively, at the time of 12 h. After 72 h, the reduction was
94.9 and 85.4% for ATCC 30011 and the clinical isolate, respectively.
Avirulent strain and clinical isolate were equally susceptible to
PHMB at 12 h, while the clinical isolate showed increased resistance
to PHMB action after 72 h, with a high viability rate.
Conclusions: Differential patterns of resistance against PHMB
were demonstrated between Acanthamoeba strains. Data suggest
the hypothesis of PHMB acts in the viability and proliferation of
trophozoites and not in the inhibition of excystment of the protozoa.
Our findings demonstrates the importance of an earlier and specific
therapeutic profile and the key role of patient in regular usage
of PHMB in order to avoid the eventual occurrence of acquired
resistance strain during the treatment for AK. Finally, the results open
perspectives about the dosage and frequency of PHMB 0.02% to be
used in the treatment of AK.
Commercial Relationships: Marina Roizenblatt, None; Linda
C. Carrijo-Carvalho, None; Annette S. Foronda, None; Fabio R.
Carvalho, None; Denise Freitas, None
Program Number: 5789 Poster Board Number: B0214
Presentation Time: 8:30 AM–10:15 AM
Corneal Pharmacokinetics of Meropenem
Henri Sueke1, 2, Tim Neal1, Stephen J. Tuft3, Mark Wilkinson2, Yalin
Zheng2, Craig Winstanley2, Stephen Kaye1, 2. 1Ophthalmology, Royal
Liverpool University Hospital, Liverpool, United Kingdom; 2Eye and
Vision Science, University of Liverpool, Liverpool, United Kingdom;
3
Ophthalmology, Moorfields Hospital, London, United Kingdom.
Purpose: To evaluate the corneal pharmacokinetics of meropenem,
a potentially novel antimicrobial in treating bacterial keratitis we
quantify (1) the toxicity of meropenem compared to moxifloxacin
on corneal cells in culture (2) the corneal penetration of meropenem
across corneas mounted on artificial anterior chambers.
Methods: Human keratocyte cells (HKCs) and human corneal
epithelial cells (HCE-Ts) in culture, were treated with either 5mg/
ml or 2.5 mg/ml of meropenem or moxifloxacin for 1 hour. MTT
cell viability assay was used to compare cell toxicity. Absorbance
was read using an automated microplate reader and cell viability was
expressed as percentages in relation to controls. Cell morphology of
HKCs and HCE-Ts were assessed with fluorescent microscopy after
incubation with meropenem compared to controls.
Human cadaver corneas were used in corneal penetration
experiments. Epithelium and endothelium were removed
mechanically and corneas were mounted onto artificial anterior
chambers. 10mg/ml of meropenem was inserted onto the corneas and
samples of fluid in the artificial anterior chamber were removed at
45minutes, 1.5hrs, 3.5hrs and 24hrs. Meropenem concentrations were
estimated from corneal homogenate and anterior chamber samples
using; (1) disc diffusion bioassay measuring zones of inhibition
when samples incubated with Escherichia Coli on agar plates and (2)
reverse-phase High-Performance Liquid Chromatography (HPLC).
Results: MTT assays of HCE-T and HKC cells showed meropenem
had significantly higher cell viability at both 5mg/ml and 2.5mg/ml
compared to moxifloxacin p<0.05. Cell morphology of meropenem
was indistinguishable from controls.
Graph 1 summarises the diffusion of meropenem across 18 corneas.
The mean corneal penetration of meropenem even at the earliest
sampling point (45 minutes) were 4 times higher than the MIC90
seen with meropenem against keratitis isolates in a previous study.
Concentrations of meropenem were seen to increase steadily
throughout the sampling time period. Meropenem concentrations
measured with bioassay were much higher than HPLC measurements.
Conclusions: We have previously shown meropenem to have
excellent in vitro activity against both Gram positive and Gram
negative isolates from patients with bacterial keratitis. This study
suggests a good safety profile against corneal cells in culture. High
corneal penetration of meropenem was seen at the earliest sampling
point well in excess of the MIC90.
Commercial Relationships: Henri Sueke, None; Tim Neal, None;
Stephen J. Tuft, None; Mark Wilkinson, None; Yalin Zheng,
None; Craig Winstanley, None; Stephen Kaye, None
Program Number: 5790 Poster Board Number: B0215
Presentation Time: 8:30 AM–10:15 AM
Besifloxacin Ophthalmic Suspension, 0.6% Compared with
Gatifloxacin Ophthalmic Solution, 0.3% for the Treatment of
Bacterial Conjunctivitis in Neonatal Patients
Tuyen Ong1, Catherine Allaire3, Timothy W. Morris2, Baldo
Sforzolini1. 1Clinical Development, Bausch & Lomb Incorporated,
Madison, NJ; 2Microbiology and Sterilization Sciences, Bausch
& Lomb Incorporated, Rochester, NY; 3European Pharmaceutical
Clinical Science, Bausch & Lomb Incorporated, Evry Cedex, France.
Purpose: To evaluate the safety and efficacy of topical besifloxacin
ophthalmic suspension, 0.6% compared with gatifloxacin ophthalmic
solution, 0.3% in the treatment of neonatal patients with bacterial
conjunctivitis.
Methods: Multicenter, randomized, double-masked, parallel
group study. Patients ≤31 days of age with a severity of grade ≥1
conjunctival discharge and conjunctival hyperemia were randomized
to besifloxacin or gatifloxacin instilled in the infected eye(s) 3 times
daily for 7 days and completed 5 study visits (3 clinic visits and 2
©2014, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at [email protected].
ARVO 2014 Annual Meeting Abstracts
phone calls). Primary endpoints included clinical resolution (absence
of both conjunctival discharge and conjunctival hyperemia) at Visit
5 (Day 8 or 9) and rates of ocular and non-ocular treatment emergent
adverse events (AEs). Microbial eradication was a secondary
endpoint.
Results: Thirty three patients (33 eyes) were randomized. Mean
(±SD) age of patients was 15.5 (6.0) days and 57.6% were female.
Of these, 22 patients (22 eyes) had culture-confirmed bacterial
conjunctivitis, most often with gram-positive bacteria. Day 8 clinical
resolution and microbial eradication appeared similar between
treatment groups. One ocular AE considered unrelated to study
treatment was reported (mild bacterial conjunctivitis in a treated
fellow eye of a gatifloxacin-treated patient). There were no treatment
related non-ocular AEs.
Conclusions: In this study with neonatal patients, both besifloxacin
and gatifloxacin appeared effective and safe in the treatment of
bacterial conjunctivitis.
Commercial Relationships: Tuyen Ong, Bausch & Lomb
Incorporated (E); Catherine Allaire, Bausch & Lomb Incorporated
(E); Timothy W. Morris, Bausch & Lomb Incorporated (E); Baldo
Sforzolini, Bausch & Lomb Incorporated (E)
Clinical Trial: 01330355
Program Number: 5791 Poster Board Number: B0216
Presentation Time: 8:30 AM–10:15 AM
Optimizing fluence settings and riboflavin composition for
collagen cross-linking (CXL) in the antimicrobial efficiency
against Pseudomonas aeruginosa and Staphylococcus aureus.
Olivier Richoz1, Florence Hoogewoud1, David Tabibian1, Arthur
Hammer1, Farhad Hafezi1, 2. 1Ophthalmology, Geneva University
Hospital, Geneva, Switzerland; 2Ophthalmology, Southern California,
Doheny Eye Institute, Keck School of Medicine, Los Angeles, CA.
Purpose: When treating bacterial keratitis, determination of the
correct pathogen is often clinically challenging. The benefits of using
CXL to treat corneal infections is that the treatment is not pathogenspecific.
In an attempt to optimize the treatment parameters, we analyzed the
effect of high fluence CXL on the bacterial killing rate in an in vitro
model using Pseudomonas aeruginosa.
Methods: The killing rate of a known concentration of bacterias
(Pseudomonas aeruginosa and Staphylococcus aureus) was analyzed
for the following conditions: 1) preservative-free riboflavin, with
UV-A irradiation @ 18 mW/cm2 for 5 minutes 2) preservative-free
riboflavin, with UV-A irradiation @ 36 mW/cm2 for 2.5 minutes 3)
riboflavin with preservatives, with UV-A irradiation @ 18 mW/cm2
for 5 minutes 4) riboflavin with preservatives, with UV-A irradiation
@ 36 mW/cm2 for 2.5 minutes 5) riboflavin only, no UVA 6)
riboflavin with preservatives, no UVA. We used 0.1% riboflavin in all
experiments.
Results: The groups with preservative-free riboflavin showed a
killing rate of 2 logs with 18 mW/cm2 and one log with 36 mW/cm2.
The groups with riboflavine with preservatives showed a killing rate
of 2 logs (98 %) with both fluences.
Conclusions: The P. aeruginosa and S. aureus killing rate is
fluence-dependent when using conventional riboflavin and fluenceindependent when preservatives are added to the riboflavin solution.
These findings will allow the generation of optimized riboflavin
solutions for the treatment of bacterial keratitis.
Commercial Relationships: Olivier Richoz, Emagine AG (I),
Emagine AG (P), Emagine AG (S); Florence Hoogewoud, None;
David Tabibian, None; Arthur Hammer, None; Farhad Hafezi,
Emagine AG (I), Emagine AG (P), Emagine AG (S)
Support: The Swiss National Science Foundation MD-PhD grant
Program Number: 5792 Poster Board Number: B0217
Presentation Time: 8:30 AM–10:15 AM
Comparative Anti-Fungal Susceptibility Analysis of Candida
Albicans versus Non-Albicans Candida Corneal Isolates
Oriel Spierer, Jyoti R. Dugar, Darlene Miller, Terrence P. O’Brien.
Ophthalmology, Bascom Palmer Eye Institute, Palm Beach Gardens,
FL.
Purpose: To compare in vitro topical amphotericin B (AMB),
natamycin, voriconazole and fluconazole in the treatment of Candida
keratitis.
Methods: Seventy two candida isolates (36 albicans and 36 nonalbicans isolates) recovered from corneal scrapings submitted to rule
out microbial keratitis, during the years 2005-2011, at the Bascom
Palmer Eye Institute, were examined. Corneal isolates were cultured
on fungal agars for 48 hours. Each yeast isolate was dispensed into
4 microtiter wells, each containing 100 microliter of commercial
(natamycin 5%) or compounded (AMB 0.15%, voriconazole 1% and
fluconazole 0.2%) antifungal medications. Microtiter plates were
incubated at 30 °C and monitored for growth or inhibition at 48
hours. A comparison of growth patterns was done.
Results: One hundred percent of the samples showed growth
inhibition after treatment with AMB or natamycin. The isolates
treated with voriconazole presented 85% inhibition rate overall,
with the Candida albicans samples showing 77% inhibition rate
and the non-albicans 93% inhibition rate. In the fluconazole group
only 19.6% inhibition rate was noted, with 7.7% inhibition rate in
the Candida albicans group versus 30% inhibition rate in the nonalbicans group.
Conclusions: AMB 0.15% and natamycin 5% have equal
effectiveness and full inhibition against Candida keratitis isolates.
Fluconazole 0.2% is not the drug of choice in both Candida albicans
and non-albicans keratitis. Voriconazole 1% may need a stronger
concentration for higher effectiveness, but may be helpful as a second
agent in the treatment of Candida keratitis.
Commercial Relationships: Oriel Spierer, None; Jyoti R. Dugar,
None; Darlene Miller, None; Terrence P. O’Brien, None
Support: Supported by NIH Center Core Grant P30EY014801,
Research to Prevent Blindness Unrestricted Grant, Department of
Defense (DOD- Grant#W81XWH-09-1-0675)
©2014, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permission
to reproduce any abstract, contact the ARVO Office at [email protected].