Serratia keratitis transmitted by contaminated eyedroppers

Evaluating and Managing the Microbial Contamination of Eye Drops: A Two-Phase Hospital-Based Study

The microbial contamination of eye drop tips and caps varies between 7.7% and 100%. In seeking patient protection and continuous improvement, the Pharmacy Department in the Sterile Ophthalmological and Oncological Preparations Unit at Cochin Hospital AP-HP, Paris, France, conducted a two-phase study to compare the antimicrobial efficiency and practical use of standard packaging and a marketed eye drop container incorporating a self-decontaminating antimicrobial green technology by Pylote SAS at the tip and cap sites. The first phase was conducted in situ to identify the microbial contaminants of eye drops used in the hospital and community settings. A total of 110 eye drops were included for testing. Staphylococcus species were the most prevalent bacteria. Candida parapsilosis was detected in only one residual content sample and, at the same time, on the cap and tip. The second phase was performed in vitro, according to JIS Z2801. Reductions above one log in Staphylococcus aureus and Pseudomonas aeruginosa counts were noted in Pylote SAS eye drop packaging after 24 h of contact. The practical tests showed satisfactory results. Pylote SAS antimicrobial mineral oxide technology exhibited promising effects that combined effectiveness, safety, and sustainability to protect the patient by preventing infections due to the contamination of eye drop containers.

Multiple use of preservative-free single dose unit dexamethasone 0.1% eye drops is safe within 24 hours

BACKGROUND

Unpreserved single-dose unit (SDU) eye drops are commonly used to avoid benzalkonium chloride-related toxicity. Although intended for single use, many patients report off-label repeated use of SDUs over a prolonged period. We investigated whether repeated use of dexamethasone 0.1% SDUs in the same patient increases the bacterial contamination rate.

METHODS

We prospectively enrolled patients scheduled for inpatient corneal and glaucoma surgery receiving dexamethasone 0.1% SDU four times per day from the same vial. To assess contamination rates, one drop from the vial was cultured immediately after opening the SDU (t0), 10 hours later after four drop applications (t10) and 24 hours after opening without further drop applications (t24). Conjunctival swabs were taken before and after drop application. Contamination rate was assessed with a standard clinical culturing protocol without introducing a positive control.

RESULTS

110 eyes of 109 patients were evaluated. Drops collected immediately after opening the SDU (t0) were contaminated in 9/110 cultures (8.1%). At t10, 13/110 cultures were contaminated (11.8%; p=0.267) and 11/110 at t24 (10.0%; t24 vs t0; p=1.00). In 5 of 21 cases of contaminated drops at t10 and/or t24, the same isolates were cultured from the initial conjunctival swab and the SDU. In three cases, the same bacterial species was found in consecutive samples.

CONCLUSION

The contamination rate of the SDU did not increase after multiple use within 24 hours. Contamination from fingertip flora was more likely than from ocular surface flora. Reuse of dexamethasone 0.1% SDU in the same patient within 24 hours appears to be safe.

Terahertz Attenuated Total Reflection Spectral Response and Signal Enhancement via Plasmonic Enhanced Sensor for Eye Drop Detection

With chronic ocular diseases such as glaucoma and dry eye syndrome, patients have to apply eye drops over the long term. The therapeutic effects of eye drops depend on the amount of drug contained and the stability of the solution. In addition, contamination during usage and transport can also negatively affect the quality and efficacy of eye drops. The current techniques for the characterization of eye drops are often complicated and time-consuming. Developing a fast and non-invasive way of accurately measuring eye drop quality remains an ongoing challenge. The biggest challenge and primary prerequisite for the application of this new detection technique for eye drops is the obtention of a sufficient spectral response and resolvable signal, considering the large background signal contributed by water. In this work, we use terahertz (THz) attenuated total reflection (ATR) spectroscopy combined with a sensitive hybrid graphene oxide (GO) and carbon nanotube (CNT) thin-film sensors to obtain distinct THz spectral signals in commercial eye drops. Various commercial eye drop products have been tested, and we show that they can be differentiated via their spectral signals. Our results provide a solid foundation for the future fine analysis of eye drops and the detection of their quality. Furthermore, THz spectroscopy combined with GO/CNT films has significant potential and advantages for the non-destructive characterization of aqueous pharmaceutical products.

Highlighting the Microbial Contamination of the Dropper Tip and Cap of In-Use Eye Drops, the Associated Contributory Factors, and the Risk of Infection: A Past-30-Years Literature Review

The sterility of eye drop content is a primary concern from manufacturing until opening, as well as during handling by end users, while microbial contamination of the dropper tip and cap are often disregarded. The contamination of these sites during drug administration represents a risk of microbial transmission and ocular infection. In this review, we aim to assess microbial contamination of the dropper tip and cap of in-use eye drops, the associated contributory factors, and the risk of infection. We conducted a literature search of the MEDLINE, PubMed, and Cochrane Central databases. A total of 31 out of 1503 studies were selected. All the studies conducted in different settings that documented microbiologically contaminated in-use eye drops were included. Our review showed that microbial contamination of the dropper tip and cap of in-use eye drops ranged from 7.7 to 100% of the total contaminated tested samples. Documented contributory factors were conflicting across the literature. Studies investigating the association between eye infection and microbial contamination of the dropper tip and cap were scarce. New technologies offer a promising potential for securing the long-term sterility of eye drop content, tips, and caps, which could benefit from more research and well-defined study protocols under real-life scenarios.

Microbial Contamination of Preservative-Free Artificial Tears Based on Instillation Techniques

Preservative-free artificial tears eliminate the side effects of preservatives but are prone to microbial contamination. This study evaluates the incidence of microbial contaminations in single-use vials of preservative-free 0.1% hyaluronate artificial tears. Based on what touched the vial tip during its first use, 60 unit-dose vials (0.5 mL) were divided into groups A (no touch, n = 20), B (fingertip, n = 20), and C (lid margin, n = 20). The vials were recapped after the first use, and the residual solution was cultured 24 h later. The solution from 20 aseptically opened and unused vials was also cultured (group D). Microbial contamination rates were compared between the groups using the Fisher’s exact test. Groups B and C contained 45% (9/20) and 10% (2/20) contaminations while groups A and D contained undetected microbial growth. The culture positivity rates were significantly different between groups A and B (p = 0.001) and groups B and C (p = 0.013) but not between groups A and C (p = 0.487). We demonstrate a significantly higher risk of contamination when fingertips touch the vial mouth. Therefore, users should avoid the vial tip touching the fingers or eyelid during instillation to prevent contamination of the eye drops.

Comparison of the Usability of Eye Drop Aids and the Conventional Bottle

(1) Background: Eye drops are the most common route of administration for ophthalmic medications. Administering drops can be a major hurdle for patients, potentially resulting in noncompliance and treatment failure. The purpose of this study is to compare the efficacy and safety of two different aids and the conventional bottle for eye drop instillation; (2) Methods: An interventional crossover study involving standard eye drop bottle, Opticare aid and Autodrop aid. The study included healthy subjects without a history of regular eye drop use; (3) Results: Twenty-six subjects were enrolled. Of those subjects, 96% and 92% were able to assemble the eye drop bottle into the Autodrop and the Opticare aids, respectively. Subjective assessment indicated that Autodrop was significantly easier to assemble than Opticare (95% CI: -1.6802 to -0.1659, p = 0.02). When using either aid, there was no contamination of the bottle tip, which occurred in 46% of subjects when no aid was used (p = 0.0005). Fewer drops were expelled when using the conventional bottle as compared to the aids (p = 0.05 compared to Autodrop, p = 0.1 compared to Opticare); (4) Conclusions: Autodrop and Opticare can assist patients with eye drop placement. These aids completely prevented bottle tip contamination, which was frequently observed when the conventional bottle was used alone.

An 18-Year Overview of Serratia marcescens Ocular Infection

PURPOSE

Serratia marcescens is a frequent ocular bacterial pathogen implicated in keratitis, endophthalmitis, and conjunctivitis. We evaluated the risk factors and treatment outcomes of ocular infections due to S. marcescens.

METHODS

In this retrospective observational study, all S. marcescens-positive cases between February 2002 and February 2020 were reviewed for ocular risk factors that included log of minimal angle of resolution visual acuity (VA), medical management, and time to epithelial defect closure.

RESULTS

Fifty-one patients were identified (72.5% females, 46.8±23.3 years). Forty-six patients had complete medical records, and 5 had microbiology data available. The most prevalent ocular risk factors were, contact lens (CL) use (68.6%), corneal disease (52.9%), and history of ocular surgery (41.2%). Mean presenting VA was 1.3±1.0. About half of the patients presented with a central ulcer (49%, 25), large infiltrate (20.4±31.8 mm2 mean), and hypopyon (43.1%, 22). All cases were reported to be susceptible to ciprofloxacin. Defect closure occurred in 52.3±117.1 days and final VA was 0.86±0.88. Adjunctive treatments were required in 14 cases (27.5%). One patient underwent surgical intervention. Features associated with poor VA outcomes included, history of glaucoma (P=0.038), older age at presentation (P<0.001), presence of hypopyon (0.045), poor VA at presentation (0.0086), time to epithelial defect closure (0.0196), and large infiltrate size (P=0.0345).

CONCLUSIONS

S. marcescens keratitis and conjunctivitis is associated with CL use and history of ocular surface disease. Worse outcomes were associated with older age, infiltrate size, presence of hypopyon, worse initial VA, longer time to epithelial defect closure, and history of glaucoma.

Bacterial Cross-Contamination in a Veterinary Ophthalmology Setting

The present study describes the prevalence of bacterial cross-contamination in a veterinary ophthalmology setting, a serious issue that can result in healthcare-associated (or nosocomial) infections among patients and staff. Retrospective (n = 5 patients) and prospective (n = 23 patients) studies evaluated bacterial isolates in companion animals presenting with ulcerative keratitis, sampling the patients' cornea and surrounding examination room, including the environment (exam table, countertop, floor) and ophthalmic equipment (slit lamp, transilluminator, direct ophthalmoscope, indirect headset, tonometer). Results of bacterial culture and antibiotic susceptibility testing were recorded, and degree of genetic relatedness was evaluated in six pairs of isolates (cornea + environment or equipment) using pulse-field gel electrophoresis (PFGE). Overall contamination rate of ophthalmic equipment, environment, and examination rooms (equipment + environment) was 42.9% (15/35 samples), 23.7% (9/38 samples) and 32.9% (24/73 samples), respectively. Methicillin-resistant Staphylococcus pseudintermedius (MRSP), a multi-drug resistant (MDR) pathogen with zoonotic potential, was isolated in 8.2% (6/73) of samples. The patient's cornea was likely the source of cross-contamination in 50% (3/6) of MRSP pairs as evaluated by PFGE; notably, two of the three similar bacterial strains did not have an exact match of their antibiotic susceptibility profiles, highlighting the importance of advanced diagnostics such as PFGE to assess cross-contamination in healthcare facilities. Future work could examine the contamination prevalence of specific equipment or the efficacy of cleaning protocols to mitigate cross-contamination in veterinary practice.

Microbial Cross-contamination in Multidose Eyedrops: The Impact of Instillation Angle and Bottle Geometry

Purpose

To evaluate the impact of instillation angle and nozzle tip geometry on cross-contamination risk of multidose ocular solution bottles.

Methods

Pseudomonas aeruginosa solution was passed exclusively on the outside of the nozzle to simulate contamination on the exterior of topical agents. Three drops were administered from angles of 90° and 45° from bottles with either a round or sharp tip geometry, and the cultures were examined for growth. Two-hundred sixteen cultures from nine lubricant eyedrop brands currently existing in the Brazilian market were assessed for bacterial growth.

Results

After seven days, bacterial contamination was detected in 53.7% of cultures when drops were administered at 90° and in 70.4% of cultures at 45°. Eyedrops collected from a rounded nozzle tip and an instillation angle of 90° transmitted bacteria in 69.4% of cases, whereas those administered from a sharp tip transmitted bacteria in only 22.2% of cases (P = 0.001). At an instillation angle of 45°, contamination was identified in 83.3% of bottles with a rounded tip geometry and in only eight of 18 bottles (44.4%) from those with a sharp nozzle geometry (P = 0.005).

Conclusions

Adjusting the instillation angle of eyedrop solutions to 90°, as well as using a nozzle geometry that prevents flow of the solution to the side of the bottle, significantly reduced contamination rates.

Translational Relevance

Standardizing drop bottles and adjusting delivery angle shows promise in reducing contamination rates and may critically impact the quality of care for patients requiring topical therapeutic agents.

[Continuous anti-glaucoma drug therapy as a risk factor of dry eye]

A preservative is a mandatory component of the eye drops designed to prevent microbial contamination in an opened bottle. Most of the preservative agents are either detergents, or oxidants; the most widely used and well-studied preservative - benzalkonium chloride - is a detergent. Due to regular usage of glaucoma eye drops, cytotoxic impact of the preservatives on anterior eye surface is considered the principal cause of its pathology, which leads to a decrease in quality of life. The high cost of preservative-free pharmacological forms and the complicated process of developing new preservatives make the usage of eye drops with minimal required concentration of preservative agent and a moistening component a good compromise. The most commonly utilized moistening component is polyvinyl alcohol - synthetic polymeric hydrogel, which is also used in artificial tears and bioengineering.

Eye drop technique and patient-reported problems in a real-world population of eye drop users

OBJECTIVE

To assess eye drop technique and patient-reported problems with eye drop instillation in a primary care sample of eye drop users.

METHODS

Cross-sectional observational study in 136 community pharmacies in Belgium. Patient inclusion criteria were being age ≥ 18 years and using eye drops for ≥ 1 month (to ensure that patients were already familiar with eye drop instillation). Participants demonstrated their eye drop technique and completed a self-administered questionnaire.

RESULTS

Participants (n = 678) had a mean age of 68.9 ± 12.4 years. During the demonstration, almost everyone (98.0%) successfully instilled at least one drop in the eye, although 14% required multiple attempts to achieve this. Only 3% of the sample exhibited perfect drop technique, meaning that they performed correctly all the steps. Most common deviations were touching the bottle to the eye or eyelid (40.7% of patients), and failing to close the eye (67.8%) and perform nasolacrimal occlusion for at least 1 min (94.7%) after drop instillation. Importantly, we found that 20% of ophthalmic suspensions were not shaken before use. Forty percent of patients reported ≥ 1 problem with eye drop instillation. Most common problems were difficulties with getting a drop in the eye (18.3% of patients), too many drops coming out of the bottle (14.6%), and difficulty squeezing the bottle (12.2%). About half of the sample recalled having had education in eye drop instillation technique.

CONCLUSION

This study showed suboptimal eye drop technique in real-world clinical practice. A proactive role of community pharmacists in detecting and resolving these problems could be helpful.

Improving eye-drop administration skills of patients - A multicenter parallel-group cluster-randomized controlled trial

Background

Eye-drop administration errors occur in the majority of patients and increase the risk for treatment failure or systemic adverse events. While lacking knowledge is the principal error cause, most patients overestimate their skills and are unaware of often substantial knowledge gaps. Therefore, the impact of including motivational patient education on long-term eye-drop administration skills of patients was investigated.

Methods

This is a cluster-randomized controlled trial in German community pharmacies. Patient education in both groups comprised observation of the patient during eye-drop administration to identify individual errors, pharmaceutical counseling, and teach-back evaluation of the training. In the intervention group, motivational communication techniques were included to increase error awareness and readiness for patient education. In addition, intervention patients were trained on repeated errors until administration was performed correctly. In contrast, patients in the control group only received feedback on erroneous administration steps without another assessment and reinforced training.

Results

In total, 152 adult patients were eligible to the study and 91 patients (intervention group N = 46) agreed to participate in a 1-month, 6-month, and 12-month follow-up. Patient education significantly increased the proportion of patients correctly administering eye-drops from 6% (7 out of 56 intervention patients, 1 out of 82 control patients) at baseline to 35% (12 out of 30 intervention patients, 12 out of 39 control patients, p ≤ 0.001) at the 1-month follow-up, and 64% (11 out of 15 intervention patients, 17 out of 29 control patients, p ≤ 0.001) at the 6-month follow-up irrespective of group allocation. In some patients previously resolved errors recurred during follow-up visits. This emphasizes the need for periodical reevaluation of patient administration skills and the provision of prevention strategies besides education.

Conclusion

Patient education that included demonstration of administration skills and verbal and written counseling on observed errors improved eye-drop administration skills irrespective of the communication technique applied. Whereof, high drop-out rates limited the power to detect a difference between groups. In particular, periodic demonstration of administration skills seemed important for sustainable improvement of administration skills. However, further error prevention strategies such as additional education materials or support by a caregiver may be necessary in some patients.

Pangenome of Serratia marcescens strains from nosocomial and environmental origins reveals different populations and the links between them

Serratia marcescens is a Gram-negative bacterial species that can be found in a wide range of environments like soil, water and plant surfaces, while it is also known as an opportunistic human pathogen in hospitals and as a plant growth promoting bacteria (PGPR) in crops. We have used a pangenome-based approach, based on publicly available genomes, to apply whole genome multilocus sequence type schemes to assess whether there is an association between source and genotype, aiming at differentiating between isolates from nosocomial sources and the environment, and between strains reported as PGPR from other environmental strains. Most genomes from a nosocomial setting and environmental origin could be assigned to the proposed nosocomial or environmental MLSTs, which is indicative of an association between source and genotype. The fact that a few genomes from a nosocomial source showed an environmental MLST suggests that a minority of nosocomial strains have recently derived from the environment. PGPR strains were assigned to different environmental types and clades but only one clade comprised strains accumulating a low number of known virulence and antibiotic resistance determinants and was exclusively from environmental sources. This clade is envisaged as a group of promissory MLSTs for selecting prospective PGPR strains.

Evaluating Eye Drop Instillation Technique and Its Determinants in Glaucoma Patients

Aim

To evaluate eye drop instillation technique and to explore its determinants in glaucoma patients.

Methods

One hundred and thirteen patients diagnosed with glaucoma and self-administering topical antiglaucoma eye drops for at least 1 month were evaluated. All patients instilled artificial tear solution in one eye as they would do at home. The whole process was evaluated by two study staff. A comprehensive score system associated with eye drop instillation techniques was used to quantify the instillation technique and explore its determinants such as demographic and clinical characteristics.

Results

Half of the patients (48.67%) finished the administration of eye drop on first attempt.1.7 eye drops were squeezed out on average. 43 patients (37.17%) got contact with ocular surface or adnexa. Only 19.7% patients had eye drop instillation techniques being defined as well. 11 patients (9.7%) had prior instruction regarding using eye drops, while only 4 patients knew to occlude the tear duct by pressing the dacryocyst area. Older age and worse visual acuity were found to be independent risk factors for worse instillation technique.

Conclusions

Eye drop instillation technique in glaucoma patients deserves great attention from eye care practitioners during their lifelong follow-up, especially those aged older and have worse visual acuity.

Bacterial Contamination of Multi-dose Eye Drops at Ophthalmology Department, University of Gondar, Northwest Ethiopia

PURPOSE:

Ophthalmic solutions used for both diagnostic and therapeutic purposes were found to be contaminated with bacteria pathogens and caused serious ocular infections such as keratitis and endophthalmitis. The objective was to assess the magnitude and pattern of bacterial contamination of multi-dose ophthalmic medications and investigate the drug susceptibility pattern of the isolates in the Department of Ophthalmology at Gondar University Teaching Hospital.

METHODS:

A total of 100 ophthalmic medications in-use by patients and eye-care workers have been taken and cultured for potential bacterial contamination in the Microbiology Department after 1 week and >1 week of use. The dropper tip and the residual eye medications were examined for contamination. The contaminating bacteria were identified using a standard procedure and drug susceptibility testing to selected antimicrobial agents was done.

RESULTS:

Eleven ophthalmic medications were contaminated by different bacterial species with a prevalence of 11%. Multi-use and longer duration of use of eye medications were associated with higher rate of contamination. The contamination level ranges from 0% for antibiotics, 20% for local anesthetics, and 40% for povidone iodine. Among bacteria identified, Staphylococcus aureus and coagulase-negative Staphylococcus species were resistant to methicillin while others were sensitive to the antibiotics tested.

CONCLUSION:

The prevalence of contamination was low, but methicillin-resistant Staphylococcus was a potential risk. It is recommended that the Department of Ophthalmology should design set of rules about duration of use and safe handling of ophthalmic medications by the staff and patients.

Clinical Characteristics of Stenotrophomonas maltophilia Keratitis

PURPOSE

Stenotrophomonas maltophilia is an important opportunistic pathogen but an uncommon cause of corneal infections. This study aimed to report the clinical features, antibiotic susceptibility, treatments, and visual outcomes of S. maltophilia keratitis.

METHODS

The medical records of 21 patients with culture-proven S. maltophilia-associated infectious keratitis in our hospital between January 1, 2003, and December 31, 2014, were retrospectively reviewed. The clinical features of patients with S. maltophilia keratitis were compared with those of patients from 17 previously reported cases.

RESULTS

The most common risk factors for S. maltophilia keratitis were preexisting corneal disease or previous corneal surgery (16), followed by soft contact lens wear (9). Nine patients (42.9%) were multifactorial. Polymicrobial infections was detected in 12 eyes (57.1%). All S. maltophilia isolates were susceptible to levofloxacin and moxifloxacin. A total of 17 of 21 patients (81.0%) had favorable responses to topical antimicrobial treatment, and 10 (47.6%) required surgical intervention for promotion of reepithelialization (6) and corneal perforation (4). Final vision ranged from light perception to 20/20. The clinical features of S. maltophilia keratitis in our cases and in previously reported cases were similar.

CONCLUSIONS

S. maltophilia keratitis primarily affects patients with compromised ocular surfaces. S. maltophilia demonstrates in vitro susceptibility and a strong clinical response to fluoroquinolones.

An upright eyedrop bottle: accuracy, usage of excess drops, and contamination compared to a conventional bottle

Purpose

This study tested the feasibility of using an upright eyedrop bottle (UEB), a device designed to assist patients with eyedrop placement without reclining their head.

Patients and methods

Experienced eyedrop users were enrolled who answered “yes” to the question, “Do you ever have trouble getting your eyedrops in?” After being shown a multimedia presentation and answering a questionnaire regarding eyedrop usage, participants were observed instilling eyedrops. Participants were instructed to instill a single eyedrop in each eye with both a standard bottle and the UEB. They repeated this process three times. With each trial, the amount of time taken to instill drops was recorded, as well as whether a drop landed in the eye (accuracy), if excess drops were used, and if the bottle tip was contaminated.

Results

Forty participants were enrolled, with an average age of 72.4±8.9 years; the majority were females (24 females). Thirty-four participants had been using eyedrops for at least 1 year. The time required to instill eyedrops was significantly less with the UEB in the second and third trials. There was no difference in accuracy between the conventional bottle and the UEB in the left or right eye in any trials. Significantly more participants used excess number of drops while using the conventional bottle in both the left and right eyes in all three trials. The bottle tip was never contaminated with the UEB. Depending on the trial and the eye, the conventional bottle was contaminated by between 42% and 53% of participants.

Conclusion

The UEB has the potential to assist patients with eyedrop placement. Although there was no difference in accuracy between the UEB and the conventional bottle, the UEB was associated with less use of excess drops and less contamination of the bottle tip, compared to the conventional bottle.

Mirror-hat device as a drop delivery aid: a pilot study

OBJECTIVE

To evaluate the effectiveness of a novel mirror-hat drop delivery aid.

DESIGN

Prospective, observational study.

PARTICIPANTS

Sixty eyes from 30 subjects with primary open-angle glaucoma or ocular hypertension attending the glaucoma unit at the Toronto Western Hospital.

METHODS

The mirror-hat device consists of a magnifying mirror attached to a brimmed cap. The aid was provided to subjects who self-administered topical antiglaucoma medications. Drop instillation technique (time taken to instill a drop, number of drops dispensed, drop contact location, and contamination of bottle tip) was evaluated with and without the device. Subjects also completed a survey regarding drop administration and satisfaction with the device.

RESULTS

Subjects were less likely to contaminate the bottle tip by touching their eye/eyelid when using the device than without the device (13% vs 37%, respectively, p = 0.02). Twenty-six subjects (86.7%) indicated they could see the drop using the device versus 12 (40%) who reported they saw the drop without the device (p = 0.0005). There were no statistically significant differences in any of the other outcomes. No predictive factors were associated with improved drop administration technique while using the device including uncorrected near-visual acuity, lens status, and glaucoma severity.

CONCLUSIONS

Use of the mirror-hat aid is associated with significantly less bottle-tip contamination and better visualization of the drop than without the device; however, the device did not help to reduce time, number of drops, or accuracy when administering eye drops.

Microbial contamination of glaucoma eyedrops used by patients compared with ocular medications used in the hospital

The aim of this study was to compare the percentage of contamination of multiuse eyedrops applied by glaucoma patients at home and by the medical personnel at the outpatient department, the ward, and the operating room of our Department of Ophthalmology. Eyedrops were collected over a period of 11 months. Samples were taken from the dropper tip (smear), drops, and the residual fluid inside the bottle and cultivated on blood agar. Colony forming units were counted and identified by mass spectrometry. The percentage of contamination was significantly higher in eyedrops applied by the patients (29/119; 24.4%, P < 0.01), used in the ward (26/133; 19.5%, P < 0.01), and in the outpatient unit (6/35; 17.1%, P = 0.036) compared with that in the operating room (6/113; 5.3%). The median period of use was 1 week in the operating room compared with 4 weeks in the other groups (P < 0.01). Glaucoma medications were significantly more frequently contaminated than antibiotic and anesthetic eyedrops (P < 0.05). For eyedrops applied by the patients, the tip was more frequently contaminated than the drops and the residual internal fluid. For eyedrops from the ward, the opposite was true. Pathogenic strains (Pseudomonas aeruginosa, Serratia marcescens, Acinetobacter lwoffii, Stenotrophomonas maltophilia, and Staphylococcus aureus) were found only in 6 bottles (1.5%), whereas most of the detected microbes belonged to human or environmental flora. This study underlines the importance of hygienic handling of eyedrops and raises the question of whether single-use glaucoma medication might be preferred to reduce the risk of contamination.

Cytoprotective effect of lacritin on human corneal epithelial cells exposed to benzalkonium chloride in vitro

PURPOSE

Benzalkonium chloride (BAK) is the most commonly found preservative in eye drops, and has been shown to cause ocular surface inflammation and toxicity. Lacritin is a human tear glycoprotein secreted from the lacrimal glands that has been found to be cytoprotective. This study was designed to determine if the presence of lacritin confers protection to a cultured human corneal epithelial (HCE) cell line, CRL-11515, and primary HCE cells after exposure to the ocular preservative agent BAK.

MATERIALS AND METHODS

Recombinant human lacritin was cloned into intein fusion vectors, expressed in E. coli, and purified on chitin beads and DEAE Sepharose. Metabolic curves were established using the MTT assay after exposure of sub-confluent CRL-11515 cells to BAK or lacritin. Western blot analysis of lipidated LC3 (LC3-II) provided a measure of autophagy in CRL-11515 cells exposed to lacritin and/or BAK.

RESULTS

BAK reduced CRL-11515 cellular metabolic activity in a time- and dose-dependent manner. BAK-induced cellular stress was evident by elevated autophagy that increased with rising concentrations of BAK compared to control (p < 0.05). Lacritin increased HCE cell proliferation at an optimal dose of 1 nM. Preconditioning HCE cells with 1 nM lacritin for 24 h prior to BAK exposure significantly dampened levels of LC3-II (p < 0.05) and promoted a significant increase in cellular metabolic activity (p < 0.01) compared to BAK alone.

CONCLUSIONS

These results suggest lacritin protects cultured HCE cells stressed with BAK. Lacritin may have the potential to be used as a topical adjunctive therapy in eyes chronically exposed to BAK.

Pseudomonas aeruginosa growth in Refresh Plus®

PURPOSE

To assess Pseudomonas aeruginosa growth in Refresh Plus(®), a unit-dose preservative-free ophthalmic solution indicated for the treatment of dry eye and after laser-assisted in situ keratomileusis (LASIK) surgery, which contains carboxymethylcellulose 0.5% as its active ingredient.

METHODS

Multiple test tubes of Refresh Plus were inoculated with 3 clinical ocular isolates of P. aeruginosa to achieve a target concentration of ∼100 colony-forming units (CFU)/mL. The tubes were incubated at 25°C and samples were aseptically removed at 6, 12, and 24 h. The samples were cultured to enumerate the population at each time point.

RESULTS

After 6 h incubation, the number of CFU/mL was 3,200 for isolate 1, 2,000 for isolate 2, and 6,480 CFU/mL for isolate 3. For all 3 organisms tested, the number of CFU/mL after 12 and 24 h incubation was >10(6) CFU/mL.

CONCLUSIONS

Under the conditions of this experiment, Refresh Plus appears to support P. aeruginosa growth, suggesting that if the solution in a unit-dose vial of Refresh Plus were contaminated with P. aeruginosa during use, the organism would survive and replicate in the solution over time. Noncompliance with the manufacturer's recommendations (i.e., reuse of an open vial) may result in contamination of the solution with P. aeruginosa, which may cause severe keratitis.

Assessment of bacterial contamination of three multidose ophthalmic solutions

OBJECTIVE

To investigate the frequency of bacterial contamination of multidose proparacaine hydrochloride, tropicamide, and eyewash bottles used in veterinary ophthalmology examination rooms during normal operating procedures.

METHODS

Three representative bottles each of proparacaine hydrochloride, tropicamide, and purified water eye wash were opened at the same time, numbered, and placed into small animal examination rooms. Doctors, students and technicians who were using the solutions were blinded to the study. Aerobic cultures were obtained at the time of opening (time 0), at 1 week (time 1), and at 2 weeks after opening (time 2) the bottles. The sites cultured included a drop of each solution, the inside of the bottle cap, the tip of the bottle, and the bottle threads and medication residue found in these threads.

RESULTS

Aerobic cultures of tropicamide and proparacaine had no growth of bacteria from any of the evaluated sites. Staphylococcus epidermidis was cultured from the tip of one bottle of eye wash after 1 week.

CONCLUSIONS

We conclude that proparacaine, tropicamide, and eyewash solutions used in veterinary examination rooms are adequately preserved for use in ophthalmic examination. They have a low level of bacterial contamination 1 or 2 weeks after opening when used and stored according to the recommendations of the product manufacturers and previous studies.

Microbial contamination of preservative free eye drops in multiple application containers

BACKGROUND/AIMS

The majority of eye drops used in the United Kingdom contain preservatives and are bottled in plastic containers. Preservative free drops are used to avoid ocular irritation and allergies in certain individuals. The aim of this study was to investigate the incidence of microbial contamination of preservative free drops dispensed from multiusage containers.

METHODS

Eye drop bottles were collected from patients attending the Tennent Institute of Ophthalmology outpatient and inpatient departments. The bottles were collected on day 3 (for inpatients) and day 7 (for outpatients) of use. The drops were inoculated onto different culture plates (chocolate agar, blood agar, fungal culture media, and enriched media) and the resulting microbial growth was identified using standard microbial identification techniques.

RESULTS

95 eye drop bottles were collected, containing a variety of 10 different eye drops. Significant bacterial growth was found in eight bottles. In total, seven different types of organism were identified from the eye drops. The organisms identified were Staphylococcus aureus, coagulase negative staphylococcus, Bacillus spp, Serattia spp, Klebsiella oxytoca, Enterobacter cloacae, and alpha streptococcus. Staph aureus was the commonest microbial organism.

CONCLUSION

Preservative free eye drops in multiple application containers are at risk of contamination by potentially pathogenic micro-organisms.

Serratia Corneal Ulcers

PURPOSE

To study the clinical and microbiological profile of Serratia corneal ulcers at the Cornea Service of the Wills Eye Hospital.

METHODS

This was a retrospective, observational case series. The clinical records of patients with Serratia marcescens corneal ulcers seen at the Cornea Service of the Wills Eye Hospital between January 1, 1998 and December 31, 2002 were reviewed.

RESULTS

Twenty-four cases of Serratia keratitis were identified in 21 patients. Two patients (9.5%) had recurrent keratitis, 1 of which recurred twice. Both had corneal graft edema and were on topical steroids and antiglaucoma drops. The Serratia infection in 15 patients (71%) was associated with an abnormal corneal surface. Twelve of these patients (57%) had the ulcer in a corneal graft, 4 (19%) of which were associated with suture infiltrates. Fifteen patients (71%) were on topical medications-15 used corticosteroids and 13 used antiglaucoma drops. Six patients (29%) were contact lens wearers-1 had a concomitant suture infiltrate associated with a corneal graft, and 5 had otherwise healthy corneas. One isolate lacked in vitro susceptibility to ciprofloxacin and ofloxacin but was susceptible to gentamicin and tobramycin. Nineteen patients had a favorable response to medical therapy. Two patients with poor outcome had large corneal ulcers with severe necrosis and thinning associated with delay in treatment.

CONCLUSIONS

Serratia marcescens keratitis is associated with the presence of an abnormal corneal surface, use of topical medications, and contact lens wear. Prompt medical therapy results in a good clinical response in the majority of cases.

Sterility of glaucoma medications among chronic users in the community

PURPOSE

To evaluate the sterility of topical glaucoma medications among chronic glaucoma medication users in the community.

SETTING

Glaucoma service, Sanz Medical Center, Laniado Hospital, Netanya. Research mode: Cross-sectional laboratory and clinical study.

PATIENTS AND METHODS

Chronic glaucoma patients were asked to submit their topical glaucoma preparations to the microbiology laboratory at Laniado hospital. Samples taken from the interior of the bottle and the tip were cultured using MacConkey agar, blood agar, and chocolate agar plates.

RESULTS

Sixty-two bottles of topical glaucoma medications used by 27 patients were tested. Bacterial growth was detected in eight (12.9%) preparations, three of which revealed Pseudomonas aeruginosa, three Staphylococcus epidermidis, one Streptococcus viridans, and one Klebsiella. During the study, acute conjunctivitis was found in one patient, possibly due to the use of infected drops. In another case, two identical medications, which had been used simultaneously for more than 6 weeks by the same patient, were found to be infected.

CONCLUSIONS

Glaucoma topical preparations are generally found safe in terms of sterility, though bacterial growth may be found in a small percentage. In most cases, the cause of the loss of sterility could not be determined. However, in two preparations, contamination was related to the noncompliance of the patient who continued using the same preparation longer than instructed. It is imperative to increase the awareness of glaucoma patients to the fact that improper use can lead to eye-drop contamination.

Ulcerative keratitis caused by Serratia marcescens after laser in situ keratomileusis

We report 2 cases of severe corneal infections caused by Serratia marcescens after laser in situ keratomileusis (LASIK). Twenty-four hours after LASIK, 2 patients developed infectious keratitis, 1 bilaterally. In each eye, the corneal flap was edematous, ulcerated, and detached from the stromal bed. Treatment included removal of the necrotic flap and aggressive antibiotic therapy. Cultures from corneal exudates were positive for S marcescens. After 1 year, both patients had a loss of best corrected visual acuity (BCVA) ranging from 20/40 to 20/22 because of irregular astigmatism. Overrefraction with a hard contact lens resulted in a BCVA of 20/20 in the 3 affected eyes. Slitlamp examination showed trace subepithelial haze without severe corneal scarring. Videokeratography disclosed areas of paracentral inferior steepening resembling keratoconus. Refraction and videokeratography remained stable after 6 months of follow-up. Ulcerative keratitis caused by S marcescens is a potential complication of LASIK. Bilateral involvement may occur if bilateral simultaneous surgery is performed.

Ocular tolerance of preservatives and alternatives

Eye drops are multiple dosage forms protected against microbial contamination by means of preservatives. However, the ocular tolerance of these chemicals can vary and this may result in adverse toxic or allergic reactions. This overview presents the pharmacopoeial requirements for the preservation of eye drops, the factors affecting ocular tolerance as well as the adverse external ocular effects induced by preservatives. The alternatives to the use of preservatives are also discussed, including the recent progress in eye drops packaging.

Endogenous Serratia marcescens endophthalmitis with dark hypopyon: case report and review

A case of endogenous Serratia marcescens endophthalmitis in a patient with diabetes, end-stage renal disease, and an indwelling venous catheter is reported. The patient presented with a tan hypopyon and elevated intraocular pressure. Diagnosis was established by positive blood, vitreous, conjunctival, and catheter tip cultures. After a deteriorating course the eye was enucleated. Gross and histopathologic examination revealed the presence of a dark hypopyon with iris necrosis and pigment dispersion and possible spontaneous globe perforation. This is the eleventh reported case of endogenous Serratia endophthalmitis. Previous association of a pink hypopyon and of pigmented vitreous fluid and Serratia endophthalmitis has been reported. This is the first case of dark hypopyon in endogenous Serratia marcescens endophthalmitis reported in the medical literature. Previous entities associated with dark hypopyon have been limited to intraocular melanoma and Listeria monocytogenes endophthalmitis. Dark hypopyon in the appropriate clinical setting may be useful in aiding diagnostic and therapeutic decisions.

The role of Serratia marcescens in soft contact lens associated ocular infections. A review

Serratia marcescens is a Gram negative rod which for a century and a half was considered a harmless saphrophyte. However, medical technology and the use of antibacterial agents have created ecological niches for this bacterium, which is now a medical problem. The bacterium is encountered in connection with contact lens keratitis, often associated with contaminated contact lens solutions. The concentrations of chlorhexidin and thiomersal required in contact lens solution to suppress the bacterium have been proved toxic to the eye. Modern contact lens solutions with biguanids have rapid killing kinetics, while in solutions with polyquaternium S. marcescens can survive in reduced numbers for up to 72 hours. The adherence of a specific isolate of Serratia to hydrogel lenses increased with decreased water content of the lenses. However, there has been no correlation between hydrophobicity markers or hemagglutinins and adherence to contact lenses or urinary tract epithelium. When handling medical plastic devices, such as contact lenses, strictly enforced hygiene remains the most important method to combat environmental bacteria such as Serratia marcescens.

Providing eye care education in the clinical setting

A strategy integrating patient managed learning and nurse directed teaching was developed with the aim of improving eye care education in the clinical setting. The effectiveness of the strategy was assessed in a quasi-experimental study involving 34 older adult patients undergoing cataract surgery. On a measure of eye care knowledge, patients taught using the strategy outperformed patients taught by conventional face-to-face methods. The strategy was found to require substantially less direct teaching time. These results are seen as justifying further clinical application and assessment of the strategy.

Microbial contamination of medications used to treat glaucoma

AIMS

A study was conducted to estimate the frequency of contamination of topical antiglaucoma medications used by asymptomatic patients.

METHODS

The drops and the bottle tips of 194 in use topical medications and the conjunctiva from 109 treated glaucoma patients were cultured.

RESULTS

Bacteria were recovered from 55 (28%) medications. The bottle tip was more frequently contaminated than the drops (p = 0.008). Gram positive organisms were cultured from 50 (91%) of 55 contaminated medications. Thirteen patients (12%) had the same microorganism recovered from the conjunctiva and from the contaminated medication. The frequency of contamination of medications increased with increasing duration of use. Bacterial contamination occurred in 19% of eyedrops less than 8 weeks old in contrast with 40% of bottles used for more than 8 weeks.

CONCLUSION

Our data suggest that ocular medications to treat glaucoma frequently become contaminated with bacteria and that contamination is related to duration of use. We therefore recommend that opened topical antiglaucoma eyedrops should be replaced on a regular basis.

The effect of adjunct questions on older adults' recall of information from a patient education booklet

The effect of adjunct questions on the amount of information retained from the reading of a patient education booklet was investigated experimentally. Ninety older adults (mean age 77 years) were assigned randomly to a treatment, treatment control or non-treatment control group, 30 in each. The treatment condition was established by having subjects spend 30 min with a booklet about post-operative eye care. The booklet included four sets of review questions. The treatment control group spent the same period with a booklet which was identical apart from the questions. Knowledge of eye care was measured using a checklist scored on the basis of responses secured in a standardised interview. Although the two treatment groups decisively outperformed the control group on the measure, no effect attributable to the adjunct questions was detected. Factors which might account for this outcome are discussed. Directions for further research and implications for practice are indicated.

Survey of the contamination of eyedrops of hospital inpatients and recommendations for the changing of current practice in eyedrop dispensing

Topical ophthalmic medications used on the ward and from the outpatient area have been taken and cultured for potential bacterial contamination in the laboratory. We examined 143 bottles used by patients who had had routine cataract surgery and trabeculectomy. We also examined for bacterial contamination 216 bottles of eyedrops used in the outpatient area of the hospital. No contamination was found in the postoperative eyedrops, but five bottles were contaminated from the outpatient area (2.3%). The bacterial growth from outpatient drops was of the same order of magnitude as in previous studies. The practice in the UK for postoperative eyedrops to be discarded and fresh, separate bottles to take home is discussed. We recommend that this practice be changed so that the postoperative drops used for 72 hours or less are taken home.

Microbial keratitis complicating penetrating keratoplasty

A retrospective review of 68 consecutive episodes of microbial keratitis complicating 66 penetrating keratoplasties (PKs) showed major risk associations: suture-related problems (50%), contact lens wear (26%), previous herpes simplex infection (15%), graft failure (15%), and persistent epithelial defects (15%). Topical steroid (85%) and antibiotic (59%) usage were common iatrogenic factors. Half the infections occurred more than 1 year after grafting. Bacterial infections involving gram-positive organisms (59%) predominated, except for patients with extended-wear hydrophilic contact lenses, which usually involved gram-negative bacilli. The incidence of fungal infections (6%) was relatively low. Recommendations to minimize microbial keratitis include prompt attention to exposed, broken, or loose sutures, and preventive and therapeutic management of epithelial defects. The inadequacy of low-dose antibiotics in precluding microbial infection in many cases and the propensity to develop infections with resistant organisms suggest that guidelines for using postoperative and prophylactic topical antibiotics require reevaluation.

Microbial keratitis associated with contaminated ocular medications

We studied seven cases of severe gram-negative microbial keratitis associated with the use of contaminated topical ocular medications. Five cases involved Pseudomonas aeruginosa, one involved Serratia marcescens, and one involved Proteus mirabilis. In each case the same organism was cultured from corneal scrapings and from the medication. Either prednisolone acetate (one case) or timolol maleate (seven cases) was implicated in all instances.

A serratial protease causes vascular permeability reaction by activation of the Hageman factor-dependent pathway in guinea pigs

The 56-kilodalton (56K) protease isolated from a culture filtrate of Serratia marcescens caused vascular permeability enhancement followed by edema formation when injected into guinea pig peripheral corneas and subconjunctival space or skin. The character and the mechanism of permeability enhancement were analyzed in vivo. The enhancement was maximum at 5 to 10 min. The permeability reaction increased exponentially by the amount of enzyme used. The enhancement of permeability induced by the 56K protease was not affected by treatment with an antihistamine but was greatly augmented by simultaneous injection of a kinin potentiator, Glu-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro-OH (SQ 20,881). Furthermore, the permeability activity of the protease, but not the amidolytic activity, was inhibited by soybean trypsin inhibitor, a well-known inhibitor of plasma kallikrein, as well as by corn trypsin inhibitor, the best inhibitor of activated Hageman factor. Results of these in vivo studies indicate that the permeability-enhancing reaction induced by the 56K protease is caused by activation of the Hageman factor-dependent pathway in the tissue. The permeability-increasing activity of the 56K protease was parallel with the enzyme activity. Serratial lipopolysaccharide did not produce a permeability enhancement reaction within 30 min when injected into guinea pig skin. These results are consistent with the results of recent in vitro experiments in which activation of the purified Hageman factor but not of prekallikrein by the 56K protease was elucidated (Matsumoto et al., J. Biochem. (Tokyo) 96:739-749, 1984). Thus, the molecular mechanism described above appears to be operative in the pathogenesis of corneal edema and chemosis, which is induced by S. marcescens, in addition to the direct tissue destruction by the protease.

Bacterial contamination of eyedrop dispensers

We undertook an in vitro investigation of the role of the design of the eyedrop dispenser in bacterial contamination. The nozzle tips of pipette and squeeze bottles containing Fluress (pH 5.0) were inoculated with 10 microliter of an ocular isolate of Pseudomonas aeruginosa (5.5 X 10(5) bacteria/ml). Cultures of single drops of ophthalmic solution (25-microliter drops from each pipette bottle and 40-microliter drops from each squeeze bottle) were done one minute, 15 minutes, one hour, two hours, and 24 hours after inoculation. Swabs from the inside of the caps of the eyedrop bottles were also cultured at similar intervals. No bacteria were recovered from either dispenser type after one hour. Swabbings from the caps of the pipette bottles showed no growth within minutes after inoculation, but swabbings from the caps of the squeeze bottles consistently yielded bacteria for 24 hours. We suggest that the cap of the squeeze bottle serves as a potential reservoir for bacterial contamination whereas direct contact of microorganisms with the preservative in an ophthalmic solution by the use of a pipette-type dispenser decreases the risk of microbial contamination and growth.

Superinfections in herpes simplex keratitis

We reviewed 15 cases of culture-proven corneal superinfections in 15 patients (eight men and seven women ranging in age from 41 to 86 years) with recurrent herpes simplex keratitis. The factors that appeared to increase the risk of superinfection were the presence of an epithelial defect (found in all 15 cases), a history of recurrent herpetic keratouveitis (found in ten cases), and the use of topical corticosteroids (found in 13 cases). Eight of the 15 patients were taking antibiotics at the time the superinfections were diagnosed, indicating that topical antibiotics do not provide sufficient protection. Gram-negative rods were found in six cases (Proteus mirabilis, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella oxytoca, Enterobacter cloacae, and Achromobacter sp.). Gram-positive organisms, often in association with another infecting agent, were found in six cases (Staphylococcus epidermidis, three cases; S. aureus, two cases; and Streptococcus sp., two cases). Fungal superinfections were found in three cases (Cephalosporium acremonium, Candida albicans, and Aspergillus fumigatus, one case each). Mycobacterium cheloni was found in two cases.