Interactions between the constitutive host defences of tears and Staphylococcus epidermidis

As part of the normal microbiota of the external eye, Staphylococcus epidermidis has probably developed strategies to overcome tear defences. The interaction of this bacteria with constitutive tear proteins was examined. Isolates of S. epidermidis grown in 10% serum or artificial tear fluid containing lysozyme or lactoferrin were resistant to the action of these proteins. Using ELISA, cell wall binding of C3, vitronectin and lactoferrin differed quantitatively between strains and in closed-eye compared to open-eye conditions. No differences were observed between ocular and non-ocular strains. This suggests that ocular isolates originate from the general host microbiota and S. epidermidis isolates are resistant to individual constitutive tear proteins.     

Antimicrobial peptides: a potential role in ocular therapy

Bacterial pathogens are often involved in contact lens‐related adverse responses. This study aimed to find antimicrobial peptides and proteins that effectively eradicate or inhibit ocular bacteria. The antimicrobials were screened against Gram‐ negative and Gram‐positive bacteria originating from ocular sources. The viability of these ocular bacteria was measured after exposure to the peptides and proteins. Two conditions were used to grow bacteria, low nutrient phosphate‐buffered saline and high nutrient tryptone soya broth. Samples were taken at different times up to 48 h. In low nutrient conditions, protamine was found to be the most effective against all strains. Melittin was very effective against all strains except Serratia and one Pseudomonas isolate which were partially affected. In high nutrient condition, only melittin was effective in killing Staphylococcus aureus. Protamine and the combination of protamine and melittin had the greatest effect in eradicating the bacteria tested in low nutrient condition. Protamine alone and its combination with melittin may have potential therapeutic agents for ocular infections in an era of emerging antibiotic resistance.     

Staphylococcus aureus ocular isolates from symptomatic adverse events: antibiotic resistance and similarity of bacteria causing adverse events

Background: Staphylococcus is the leading cause of microbial keratitis. Staphylococcus aureus isolated from ocular infections with resistance to a wide range of antibiotics, including the commonly prescribed fluoroquinolones, is emerging. The aim of this study was to determine the current antibiotic susceptibilities of ocular S. aureus isolates and also determine whether isolates from different adverse events or those with similar antimicrobial susceptibilities are related. Methods: A collection of 55 S. aureus strains from ocular adverse events were analysed for antibiotic susceptibility using disc diffusion (CDS method) and typed using PCR‐ribotyping and pulsed‐field gel electrophoresis (PFGE). Results: S. aureus isolated from symptomatic ocular adverse events in the USA exhibited greater resistance to antibiotics than did those isolated from symptomatic ocular adverse events in Australia or India (p < 0.05). A larger proportion of ulcerative keratitis isolates was found to be resistant to antibiotics than isolates from conjunctivitis. PFGE analysis separated related isolates determined by ribotype, on the basis of the adverse event caused by the isolate. Isolates were related within geographical regions and adverse event types. Conclusions: Similar isolates within a geographical location cause adverse events but there is a genetic difference between isolates causing corneal adverse events and those causing conjunctivitis. Isolates from corneal adverse events were more resistant to antibiotics, with those from the USA exhibiting the greatest resistance. This suggests that virulence may correlate with increased resistance to antibiotics.     

反复使用抗生素患者结膜菌群的变化及耐药模式研究

目的：观察和分析反复使用抗生素患者结膜菌群的变化。此外,确定这种反复暴露对结膜菌群抵抗模式的影响。

方法：研究纳入40例眼科研究所视网膜科患者。所有受试者至少进行了连续4次、每月一次的玻璃体腔注射(IVI),其中一些患者根据需要延长至6mo或1y。将患者随机分为3组,每组给予氧氟沙星、莫西沙星或头孢他啶任意一种抗生素。使用Kirby-Bauer扩散法对所有细菌进行药敏试验。

结果：研究中,以表皮葡萄球菌(51.2%)为主,其次是金黄色葡萄球菌(14%),微球菌(12.8%)和其他凝固酶阴性葡萄球菌(CONS)占13%。结果显示,在4次随访中,与随机接受头孢他啶治疗的患者的基线培养相比,接受头孢他啶治疗的患者眼部表皮葡萄球菌的百分比有所增加。相比之下,与基线相比,金黄色葡萄球菌的百分比没有明显增加。在氟喹诺酮治疗眼中观察到表皮葡萄球菌的百分比从基线增加。与头孢他啶治疗组相比,氟喹诺酮治疗组的金黄色葡萄球菌百分比较基线升高。然而,随着新一代和老一代氟喹诺酮类药物的暴露,眼部菌群组成模式发生了变化。我们注意到,从基线开始,莫西沙星治疗组比氧氟沙星治疗组的表皮葡萄球菌增多。暴露于老一代和新一代氟喹诺酮类药物的金黄色葡萄球菌的模式没有差异。

结论：反复使用眼用抗生素不仅会改变正常眼部菌群的组成,还会选择耐药菌株。     

Ocular surface microbiota in patients with aqueous tear-deficient dry eye

PurposeAn altered ocular surface microbiota may contribute to the pathophysiology of dry eye disease. The aim of the study was to explore potential differences in microbiota diversity and composition in aqueous tear-deficient dry eye (with and without ocular graft-versus-host disease) compared with controls.MethodsSwab samples from the inferior fornix of the conjunctiva were obtained from patients with aqueous tear-deficient dry eye with and without ocular graft-versus-host disease (n = 18, n = 21, respectively) and controls (n = 28). Isolated bacterial DNA from swabs were analyzed with 16S rRNA gene amplicon sequencing.ResultsDecreased microbiota diversity was observed in patients with aqueous tear-deficient dry eye (p ≤ 0.003) who also showed a difference in microbiota composition compared with controls (p = 0.001). Although several genera were less abundant in aqueous tear-deficient dry eye, a minimal core ocular surface microbiota comprising five genera was shared by >75% of the study participants: Enhydrobacter, Brevibacterium, Staphylococcus, Streptococcus and Cutibacterium. Pseudomonas was identified as a bacterial biomarker for controls and Bacilli for patients with aqueous tear-deficient dry eye.ConclusionsOcular surface microbiota in patients with aqueous tear-deficient dry eye was characterized by an aberrant microbiota composition in comparison to controls, with decreased diversity and reduced relative abundances of several genera. Additionally, a few genera were present in most of the study population, indicating that a minimal core ocular surface microbiota may exist.     

Normal ocular flora in healthy eyes from a rural population in Sierra Leone

Purpose To identify the normal conjunctival flora in a rural population in Sierra Leone and compare the normal ocular flora of a developing country with that of the developed world. Methods Conjunctival swabs obtained from healthy right eyes of 276 residents of Masungbo, Sierra Leone, were analyzed for growth of microorganisms. Results The most commonly isolated organisms from conjunctival swabs of healthy eyes were coagulase-negative Staphylococcus (28.6%), fungus (26.0%), Staphylococcus aureus (19.9%), Gram negatives other than Pseudomonas/Haemophilus (9.8%), Nocardia/Actinomyces (6.5%), and Pseudomonas aeruginosa (6.2%). Conclusions There is a high prevalence of fungal and bacterial colonization of healthy eyes in a rural population of Sierra Leone. A relationship may exist between resident normal flora and the etiology of ocular infections.     

Aerobic bacterial flora of the normal conjunctiva at high altitude area of Shimla Hills in India:a hospital based study

AIM:To study the normal aerobic conjunctival flora in lower to mid Himalayan region of Shimla Hills.METHODS:Samples from normal conjunctiva of 200 individuals above the age of 13 years who visited Indira Gandhi Medical College Hospital Shimla for refraction or cataract surgery were taken by anaesthetising the conjunctival sac with sterile 4% Xylocaine solution. Samples were obtained by gently rubbing lower fornix with a sterile cotton wool swab moistened with normal saline and keeping the eye lids wide apart to avoid contamination from lid margins. It was immediately inoculated in Brain Heart infusion and subjected to standard aerobic culture and identification techniques.RESULTS:Totally, 72 eyes (36%) conjunctival sacs were sterile. Predominant aerobes isolated were Staphylococcus spp. in 120 (60%) followed by Haemophilus in 16 (8%), diphtheroids in 10 (5%), and Escherichia.coli (E. coli) in 4 (2%). A single aerobe was isolated from 98 eyes (49%) while 30 eyes (15%) yielded more than 1 aerobe. Staphylococcus epidermidis (S.epidermidis) was the most common bacterium, found alone in 58 eyes (29%) and in combination with another aerobe in 30 eyes (15%), followed by Staphylococcus aureus (S. aureus) in 18 (9%) and 10 eyes (5%) respectively.CONCLUSION:S. epidermidis is the most common commensal organism followed by Haemophilus species. diphtheroids occupied the third position which otherwise are found more abundantly in literature. Pathogens like S. aureus, Staphylococcus citreus and E. coli were also found. Therefore, preoperative administration of topical broad spectrum antibiotics is extremely important in prophylaxis against ocular infection. The variation in microflora of normal conjunctiva in this part of world can be attributed to geographical, climatic and ethnic characteristics of the population under study.     

Early intravitreal treatment of endogenous bacterial endophthalmitis

Background: There are currently no standardized treatment guidelines for endogenous bacterial endophthalmitis. We report the long‐term outcomes of early intravitreal treatment of endogenous bacterial endophthalmitis, defined as intravitreal and systemic antibiotics administered within 24 h of diagnosis, with conservative use of pars plana vitrectomy. Design: Interventional retrospective case series. Participants: Consecutive patients treated for culture‐proven endogenous bacterial endophthalmitis between 2001 and 2008 at the Weill Cornell Medical Center. Methods: The clinical records of 18 eyes from 13 patients were reviewed. Main Outcome Measures: Visual acuity. Results: Mean age at presentation was 61 (25–85) years. All patients had underlying medical conditions. Extraocular infectious foci were identified in nine (69%) patients, with endocarditis being the most common. Gram‐positive organisms were identified in 12 (92%) patients, including five with methicillin‐resistant Staphylococcus aureus. No cases were misdiagnosed. Final visual acuities of better than 6/120 and counting fingers were achieved in 6 (55%) and 7 (64%) of 11 eyes, respectively. Longer time between onset of ocular symptoms and intravitreal antibiotic injection correlated with worse visual outcomes (P < 0.05) and was associated with mortality (P < 0.05). Mortality was also associated with methicillin‐resistant S. aureus infection (P < 0.05). Of those with follow up longer than 1 year, retinal detachment developed in 3 of 10 eyes (30%) after the acute infection, and cataract developed in 6 of 9 (67%) phakic eyes. Mean follow up was 146 (4–313) weeks. Conclusions: Intravitreal antibiotics for endogenous bacterial endophthalmitis administered within 24 h to supplement immediate systemic antibiotics may provide a relatively favourable visual prognosis.     

翼状胬肉患者眼表微生物菌群分析

目的：研究翼状胬肉患者的眼表微生物菌群组成,探索眼表微生物菌群和翼状胬肉的相关性。

方法：收集2018-09/2019-01在我院就诊的原发性翼状胬肉患者,翼状胬肉组为患翼状胬肉的26眼,正常对照组为9只对侧正常眼,采用MiseqPE301+8+8+301平台进行细菌16S rDNA基因V3～V4区双端测序,分析比较翼状胬肉组与正常对照组眼表微生物菌群结构与组成差异。

结果：两组样品共得到1 837个OTU; Alpha多样性分析,正常对照组物种的多样性高于翼状胬肉组。同时两组优势菌群相似。构成以棒状杆菌、葡萄球菌、链球菌、丙酸杆菌等革兰氏阳性菌为主,其次为革兰氏阴性菌。棒状杆菌在翼状胬肉组比例增高。

结论：翼状胬肉组眼表物种多样性下降,棒状杆菌在翼状胬肉患者眼表菌群的丰度显著增高,可能参与眼表免疫状态调节,并影响翼状胬肉的发生与发展。     

Microbial keratitis in Waikato, New Zealand

Background: Bacterial keratitis is a potentially sight‐threatening condition. This study is performed to identify the common causative organisms for bacterial keratitis in Waikato region and the antibiotic sensitivities to these organisms. Design: Retrospective, observational, case series. Participants: The microbiology records of all patients with bacterial keratitis who presented to the Ophthalmology department, Waikato Hospital, New Zealand between January 2003 and December 2007. Methods: The corneal scrape results were reviewed. Antibiotic sensitivity for the organism was tested following National Committee for Clinical Laboratory Standards (NCCLS) method. Main Outcome Measures: In vitro laboratory susceptibility testing of ocular isolates to various antibiotics. Results: A total of 265 scrapes were performed. Gram stain was positive in 35 (13.2%) eyes. Positive culture was seen in 174 (65.6%) scrapes; 78.2% were Gram‐positive and 20.2% were Gram‐negative organisms. Most common Gram‐positive organisms were coagulase‐negative Staphylococci (40.8%) and Staphylococcus aureus (11.5%). Most common Gram‐negative organisms were Moraxalla species (8.0%) and Pseudomonas aeroginosa (3.4%). Of the bacterial organisms 99% were sensitive to ciprofloxacin. All Gram‐negative organisms and 95.5% Gram‐positive organisms were sensitive to tobramycin; 96.6% Gram‐positive organisms and 98.3% Gram‐negative organisms were sensitive to cefuroxime. Conclusions: Our results are comparable to other regions in New Zealand but the incidence of coagulase‐negative Staphylococcus is much higher in this region compared with other New Zealand studies. It seems appropriate to start patients with corneal ulcers initially on fluoroquinolone monotherapy while awaiting culture results.     

Staphylococcus aureus and its Bearing on Ophthalmic Disease

Purpose: To review antibiotic resistance associated with S. aureus endophthalmitis and the virulence of S. aureus.

Methods: Review of the current and prospective approaches for treating S. aureus endophthalmitis.

Results: Bacterial endophthalmitis remains to be a major threat for vision. S. aureus endophthalmitis specifically, carries a poor visual prognosis making early diagnosis and treatment crucial. Methicillin resistant Staphylococcus aureus (MRSA) endophthalmitis represents a significant number of S. aureus endophthalmitis cases. MRSA with reduced susceptibility to glycopeptide antibiotics such as vancomycin (vancomycin intermediate S. aureus, VISA) have also emerged in the ocular infections, and there has been a rise in S. aureus resistance to new and old generation fluoroquinolones that are commonly used for prophylaxis after intravitreal injections and intraocular surgeries.

Conclusions: With the rise in the number of penetrating procedures in the ophthalmology practice and the parallel rise in antibiotic resistance, prophylaxis and awareness of the antimicrobial resistance profiles remain crucial and the identification of novel antimicrobials is essential.     

Ocular immunity to Staphylococcus aureus

Staphylococcus aureus is an important cause of infectious disease of the eye and hypersensitivity lesions of the cornea including phlyctenules and catarrhal infiltrates. Because little is known about ocular immunity to S. aureus, we measured antibody levels to ribitol teichoic acid, the major antigenic determinant of S. aureus, in rabbit serum and tears using an enzyme-linked immunosorbent assay after immunization with S. aureus antigens using the following routes: intradermal injection of cell wall mixed with complete Freund's adjuvant, subconjunctival injection of cell wall mixed with complete Freund's adjuvant, topical application of cell wall to the eye, and topical application of viable S. aureus to the eye. All four immunization groups showed an IgG antibody response to ribitol teichoic acid in serum and tears with the highest titers in serum found after intradermal immunization with cell wall and the highest titers in tears found after topical application of S. aureus. All four immunization routes showed an IgA antibody response to ribitol teichoic acid in tears with the highest titers found after subconjunctival immunization with cell wall. There was no IgA response to ribitol teichoic acid in serum in any group. The results of this study suggest that ocular immune responses to S. aureus may be influenced by exposure to staphylococcal antigens not only in the external eye but also at sites remote from the eye.     

Intraocular anti-Toxoplasma gondii IgA antibody production in patients with ocular toxoplasmosis

PURPOSE: To investigate the immunoglobulin classes associated with the intraocular anti-Toxoplasma gondii antibody response during clinical ocular toxoplasmosis and to determine which immunoglobulin class is most helpful in the diagnosis of this disease. METHODS: Paired serum and intraocular fluid samples from 155 patients who had uveitis were tested for intraocular anti-T. gondii IgG, IgA, and IgM antibody production. The presence of T. gondii DNA was determined by polymerase chain reaction. Patients were divided into two groups, based on the initial clinical diagnosis; group 1 included 78 patients with presumed ocular toxoplasmosis, and group 2 included 77 patients with uveitis that was not clinically suspected to be ocular toxoplasmosis. Samples from 27 nonuveitis patients who underwent intraocular surgery were used as control subjects. The final diagnosis was based on the clinical course and interpretation of laboratory tests. RESULTS: A final diagnosis of ocular toxoplasmosis was made in 88 of 155 patients (group 1, 68; group 2, 20). Among these patients, 65% had intraocular IgG production, 52% had intraocular IgA production, 37.5% had both IgG and IgA production, 27% had IgG production only, and 15% had IgA production only. Of the 13 patients tested, only one had intraocular IgM production. Intraocular IgA could not be detected in patients who had final diagnoses other than ocular toxoplasmosis or in control subjects. A positive polymerase chain reaction combined with a test that was positive for intraocular IgG production had a sensitivity of 77%, which increased to 91% after the detection of intraocular IgA production was added. CONCLUSIONS: Immunoglobulin G is the major class involved in the humoral immune response against the T. gondii parasite, followed by IgA. The determination of IgA production is useful as an additional test in the diagnosis of ocular toxoplasmosis.     

儿童眼肌型重症肌无力免疫相关发病机制的初步探讨

目的:通过分析儿童眼肌型重症肌无力患儿外周血中免疫球蛋白、补体及T细胞亚群的含量,初步探讨体液免疫和细胞免疫在儿童眼肌型重症肌无力发病中的作用。方法:采用免疫比浊法检测37例儿童眼肌型重症肌无力患儿及健康对照儿童外周血中IgG,IgA,IgM,补体C3及C4的含量,流式细胞术检测12例儿童眼肌型重症肌无力患儿及健康对照儿童外周血中CD3+T淋巴细胞、CD4+T淋巴细胞及CD8+T淋巴细胞的含量,独立样本t检验进行数据统计分析。结果:儿童眼肌型重症肌无力患儿外周血IgA,IgM及CD3+T淋巴细胞、CD8+T淋巴细胞值与健康儿童比较,均无显著性差异(P>0.05),IgG,补体C3及C4的含量低于健康儿童(P<0.05)。CD4+T淋巴细胞值高于对照儿童(P<0.05)。结论:补体C3,C4及CD4+T淋巴细胞在儿童眼肌型重症肌无力的发病机制中起着重要作用。     

Autoantibodies in patients with glaucoma: a comparison of IgG serum antibodies against retinal,optic nerve,and optic nerve head antigens

Purpose The aim of this study was to analyze and compare the entire IgG autoantibody patterns against different ocular antigens (retina, optic nerve, and optic nerve head) in sera of glaucoma patients and healthy subjects.Methods Sixty-six patients were included in this study: healthy volunteers without any ocular disorders (CO, n=30), patients with primary open-angle glaucoma (POAG, n=19), and patients with normal-tension glaucoma (NTG, n=17). The sera were tested for antibodies against retinal, optic nerve, and optic nerve head tissues. Immunodetection was performed using 4-chloro-1-naphthol staining. The autoantibody patterns were digitized and subsequently analyzed by multivariate statistical techniques.Results All patients showed a complex repertoire of IgG antibodies against retinal, optic nerve, and optic nerve head antigens. The analysis of discriminance revealed a statistically significant differences between the patterns of all three groups. Our multivariate approach could quantify the differences in immunoreactivities of patient sera against the three antigens. The POAG group had the most significant difference against retinal antigens (P=0.0021) compared with the other antigens. In the NTG group the highest reactivity appeared against optic nerve head (P=0.00053) and optic nerve (P=0.0025).Conclusions All groups showed different and complex antibody patterns against the three ocular tissues. These autoantibodies are highly specific for each patient group. The analysis of these patterns could provide further information about possible autoimmune mechanisms in the pathogenesis of glaucoma.     

Secretory immunoglobulin A in tears: functions and changes during contact lens wear

Introduction : Secretory immunoglobulin A (sIgA) is the predominant immunoglobulin in tears. The role of sIgA in defending the eye against pathogens has not been established clearly. There have been conflicting reports about the effect of contact lens wear on the concentration of sIgA in tears. This study was conducted to elucidate the role of sIgA in ocular defence and to determine the effect of contact lens wear on sIgA concentration. Methods : Tears were collected from contact lens wearers and non-wearers using microcapillary tubes. The concentration of sIgA was evaluated using an in-house ELISA. The specificity of sIgA to a strain of P. aeruginosa was examined using a fluorescent assay and the ability of neutrophils to phagocytose sIgA coated bacteria were assessed by plate counts. Results : Tears contained sIgA that reacted to P. aeruginosa. P. aeruginosa coated with sIgA was phagocytosed by the neutrophils. The level of sIgA and the level of sIgA specific to P. aeruginosa in the tears of contact lens wearers were significantly reduced. Conclusions : These results indicate that contact lens wear significantly alters the level of sIgA in tears which may lead to changes in the ability of the ocular surface to defend itself against potential pathogens.     

Corneal antibody levels to ribitol teichoic acid in rabbits immunized with staphylococcal antigens using various routes

Although Staphylococcus aureus is an important cause of infectious diseases of the eye and hypersensitivity lesions of the cornea, little is known about ocular immunity to this pathogen. Using an enzyme-linked immunosorbent assay, we measured antibody titers to ribitol teichoic acid, the major antigenic determinant of S. aureus, in corneas as well as serum and tears after immunizing rabbits using the following routes: intradermal injection of cell wall mixed with complete Freund's adjuvant, subconjunctival injection of cell wall mixed with complete Freund's adjuvant, topical application of cell wall to the eye or topical application of viable S. aureus to the eye. IgG titers to ribitol teichoic acid were found consistently in corneas after intradermal and subconjunctival immunization with cell wall and topical immunization with viable S. aureus. After intradermal immunization with cell wall, IgG titers in cornea were higher than tears but lower than serum, which was presumably the source of the IgG antibodies for the cornea. After subconjunctival immunization with cell wall or topical immunization with viable S. aureus, IgG titers in corneas were higher than tears and generally higher than serum, suggesting that the ocular tissues were a local source of IgG. On the other hand, IgA titers to ribitol teichoic acid were found in tears but not in serum and were found only occasionally in corneas, suggesting that IgG responses to staphylococcal antigens may be more important than IgA responses in the cornea. The results of this study suggest that corneal antibodies to ribitol teichoic acid may be influenced by exposure to staphylococcal antigens not only in the external eye but also at sites remote from the eye.     

Effect of storage temperatures and time on the efficacy of multipurpose solutions for contact lenses

PURPOSE: To determine the effect of storage time and temperature on the efficacy of four multipurpose solutions for soft contact lenses. METHOD: Aliquots of multipurpose solutions (OPTI-FREE Express, ReNu MultiPlus, COMPLETE and SOLO-care) stored at different temperatures over a 3-month period, were challenged with contact lens-related ocular pathogens, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. RESULTS: The results showed that OPTI-FREE Express had the best activity against Ps. aeruginosa at all temperatures; ReNu MultiPlus performed well at 25 degrees C; COMPLETE barely achieved activity requirements at all temperatures, and lost efficacy after 2 months. SOLO-care maintained its activity best against Ps. aeruginosa at 30 degrees C. Storage at fridge temperature reduced activity of all solutions. Regardless of storage temperature, activities of all solutions against S. aureus markedly decreased by 2 months. Only OPTI-FREE Express met FDA requirements against C. albicans. CONCLUSION: Performance of multipurpose solutions is affected by time and temperature of storage. Contact lens users should be aware that the efficacy of opened solutions may not be sustained for as long as 3 months. Manufacturers should reconsider their recommendations to further safeguard the ocular health of contact lens wearers.     

Apoptotic mechanisms within the retina in <Emphasis Type="Italic">Staphylococcus epidermidis</Emphasis> experimental endophthalmitis

Aim  To investigate the potential involvement of apoptosis and its regulators Bcl-2, Bax, and Fas within the retina in Staphylococcus epidermidis experimental endophthalmitis. Methods  Endophthalmitis was induced in 48 male Lewis rats by unilateral 25-μl intravitreal injection of 7,000 viable organisms of slime-producing S. epidermidis strain ATCC 35983 (experimental group). Forty-eight other Lewis rats received a similar sterile normal saline injection (control group). The injected eyes were graded for clinical inflammation and were removed in groups at 6, 12, 24, 48, 72, and 168 hours post-injection. After surgical separation, retinal tissue specimens were fixed, and paraffin sections underwent hematoxylin-eosin staining, immunohistochemistry against Bcl-2, Bax, and Fas, and TUNEL assay for detection of apoptotic cells. Following morphometric analysis, the apoptotic body index (ABI) was calculated. Results  While Bcl-2 expression was absent, Bax and Fas expression and apoptosis in ganglion cells, bipolar cells, and photoreceptors, were significantly higher in the experimental group compared to the control group (P < 0.05). In the experimental group, inflammation peaked at 24 hours, Bax and Fas expression at 48 hours and the ABI at 72 hours post-injection. Conclusion  Apoptosis is increased within the retina in S. epidermidis experimental endophthalmitis through upregulation of Bax and Fas, peaking soon after peak inflammation. Support: None Financial interest: None     

Risk Factors for Fluoroquinolone Resistance in Ocular Cultures

Purpose

To identify the risk factors associated with fluoroquinolone resistance in patients undergoing cataract surgery.

Methods

A total of 1,125 patients (1,125 eyes) who underwent cataract surgery at Veterans Health Service Medical Center from May 2011 to July 2012 were enrolled in this study. Conjunctival cultures were obtained from the patients on the day of surgery before instillation of any ophthalmic solutions. The medical records of patients with positive coagulase negative staphylococcus (CNS) and Staphylococcus aureus (S. aureus) cultures were reviewed to determine factors associated with fluoroquinolone resistance.

Results

Of 734 CNS and S. aureus cultures, 175 (23.8%) were resistant to ciprofloxacin, levofloxacin, gatifloxacin, or moxifloxacin. Use of fluoroquinolone within 3 months and within 1 year before surgery, topical antibiotic use other than fluoroquinolone, systemic antibiotic use, recent hospitalization, ocular surgery, intravitreal injection and use of eyedrops containing benzalkonium chloride were significantly more frequent in resistant isolates than in susceptible isolates. In multivariable logistic regression analysis, ocular surgery (odds ratio [OR], 8.457), recent hospitalization (OR, 6.646) and use of fluoroquinolone within 3 months before surgery (OR, 4.918) were significant predictors of fluoroquinolone resistance, along with intravitreal injection (OR, 2.976), systemic antibiotic use (OR, 2.665), use of eyedrops containing benzalkonium chloride (OR, 2.323), use of fluoroquinolone within 1 year before surgery (OR, 1.943) and topical antibiotic use other than fluoroquinolone (OR, 1.673).

Conclusions

Recent topical fluoroquinolone use, hospitalization and ocular surgery were significantly associated with fluoroquinolone resistance in CNS and S. aureus isolates from ocular culture.