Microbial Keratitis in Los Angeles

A double-masked, sham-controlled trial of rose bengal photodynamic therapy for the treatment of fungal and acanthamoeba keratitis: Rose Bengal Electromagnetic Activation with Green Light for Infection Reduction (REAGIR) study

BACKGROUND

Infectious keratitis secondary to fungus or acanthamoeba often has a poor outcome despite receiving the best available medical therapy. In vitro rose bengal photodynamic therapy (RB-PDT) appears to be effective against fungal and acanthamoeba isolates (Atalay HT et al., Curr Eye Res 43:1322-5, 2018, Arboleda A et al. Am J Ophthalmol 158:64-70, 2014). In one published series, RB-PDT reduced the need for therapeutic penetrating keratoplasty in severe bacterial, fungal, and acanthamoeba keratitis not responsive to medical therapy.

METHODS

This international, randomized, sham and placebo controlled 2-arm clinical trial randomizes patients with smear positive fungal and acanthamoeba and smear negative corneal ulcers in a 1:1 fashion to one of two treatment arms: 1) topical antimicrobial plus sham RB-PDT or 2) topical antimicrobial plus RB-PDT.

DISCUSSION

We anticipate that RB-PDT will improve best spectacle-corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via ClinicalTrials.gov website, meetings, and journal publications. Our data will also be available upon reasonable request.

TRIAL REGISTRATION

NCT, NCT05110001 , Registered on November 5, 2021.

Perspectives on the Incidence of Acanthamoeba Keratitis: A Systematic Review and Meta-Analysis

TOPIC

To provide an overview on the incidence of Acanthamoeba keratitis (AK).

CLINICAL RELEVANCE

Although being a sight-threatening cause of infectious keratitis, a comprehensive assessment of the incidence of AK is lacking.

METHODS

Incidence of AK was computed as the number of eyes with AK per health care center, per year (annualized center incidence [ACI]). Two meta-analytical ratios also were calculated: (1) the ratio of eyes with AK to the count of eyes with nonviral microbial keratitis (MK) and (2) the ratio of eyes with AK to the overall population (i.e., the total number of people in a nation or region, as indicated by the authors in each study). Center was defined as the health care facility where the study took place. Actual and projected estimates of the number of eyes with AK in years were calculated multiplying the ratio of eyes with AK to the total population and the corresponding population estimates, sourced from the United Nations Population Prospects.

RESULTS

Overall, 105 articles were included, published between 1987 and 2022. The total number of eyes identified was 91 951, with 5660 eyes affected by AK and 86 291 eyes affected by nonviral MK. The median ACI was 1.9 eyes with AK per health care center per year (95% confidence interval [CI], 1.5-2.6 eyes), with no statistically significant differences among continents. The ratio of eyes with AK to the total number of eyes with MK was 1.52% (95% CI, 1.03%-2.22%), whereas the ratio of eyes with AK in relationship to the entire population was estimated at 2.34 eyes per 1 000 000 people (95% CI, 0.98-5.55 per 1 000 000 people). The projected increase in the numbers of eyes with AK indicated an increase of 18.5% (n = 15 355 eyes with AK) in 2053 and 25.5% (n = 16 253 eyes with AK) in 2073, compared with the baseline of 2023 (n = 12 953 eyes with AK).

DISCUSSION

Acanthamoeba keratitis emerged as a relatively low-incident disorder, and no significant differences in terms of its incidence were found among different continents.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

A double-masked, sham-controlled trial of rose bengal photodynamic therapy for the treatment of fungal and acanthameoba keratitis: Rose Bengal Electromagnetic Activation with Green Light for Infection Reduction (REAGIR) Study

Background

Infectious keratitis secondary to fungus or acanthamoeba often has a poor outcome despite receiving the best available medical therapy. In vitro Rose Bengal Photodynamic therapy (RB-PDT) appears to be effective against fungal and acanthamoeba isolates.22,23 In one published series RB-PDT reduced the need for therapeutic penetrating keratoplasty in severe bacterial, fungal, and acanthameoba keratitis not responsive to medical therapy.

Methods

This international, randomized, sham and placebo controlled 2-arm clinical trial, randomizes patients with smear positive fungal and acanthameoba and smear negative corneal ulcers in a 1:1 fashion to one of two treatment arms: 1) Topical antimicrobial plus sham RB-PDT or 2) Topical antimicrobial plus RB-PDT.

Discussion

We anticipate that RB-PDT will improve best spectacle corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via clinicaltrials.gov website, meetings, and journal publications. Our data will also be available upon reasonable request.

Trial Registration

NCT, NCT05110001, Registered November 5, 2021. https://www.clinicaltrials.gov/study/NCT05110001.

Impact of SARS-CoV-2 pandemic and lockdown measures on microbial keratitis in Taiwan

PURPOSE

This study aimed to evaluate how the SARS-CoV-2 pandemic and associated lockdown measures influenced microbial keratitis in Taiwan by comparing demographic data, predisposing factors, pathogen profiles, and treatment outcomes in 2019 and 2020.

METHODS

Data from patients diagnosed with microbial keratitis at National Chung Kung University Hospital between January 2019 and December 2020 were examined, focusing on patient demographics, predisposing factors, isolated pathogens, antibiotic usage, and clinical progress.

RESULTS

No significant differences were found in patient sex, laterality, or average age between the two years. Predisposing factors, such as contact lens use and chronic ocular/systemic disorders, remained unchanged. While fungal isolates slightly increased during the lockdown, bacterial isolates remained consistent. Medical treatment effectiveness, treatment strategies, and antibiotic susceptibility for common bacteria showed no significant alterations.

CONCLUSION

Despite the challenges posed by the SARS-CoV-2 pandemic and lockdown measures, this study revealed minimal changes in microbial keratitis trends in Taiwan. This highlights the importance of maintaining access to medical care during crises and offers insights into potential treatment strategies for patients facing difficulties in receiving timely care. Further research should investigate the pandemic's impact on healthcare access and patient outcomes in various populations and regions.

Antimicrobial resistance in ocular infection: A review

Antimicrobial resistance (AMR) is a global public health threat with significant impact on treatment outcomes. The World Health Organization's Global Action Plan on AMR recommended strengthening the evidence base through surveillance programs and research. Comprehensive, timely data on AMR for organisms isolated from ocular infections are needed to guide treatment decisions and inform researchers and microbiologists of emerging trends. This article aims to provide an update on the development of AMR in ocular organisms, AMR in bacterial ocular infections and on AMR stewardship programs globally. The most common ocular pathogens are Pseudomonas aeruginosa, Staphylococcus spp., Streptococcus pneumoniae, and Haemophilus influenzae in ocular infections. A variety of studies and a few surveillance programs worldwide have reported on AMR in these infections over time. Fluoroquinolone resistance has increased particularly in Asia and North America. For conjunctivitis, the ARMOR cumulative study in the USA reported a slight decrease in resistance to ciprofloxacin. For keratitis, resistance to methicillin has remained stable for S. aureus and CoNS, while resistance to ciprofloxacin has decreased for MRSA globally. Methicillin-resistance and multidrug resistance are also emerging, requiring ongoing monitoring. Antimicrobial stewardship (AMS) programmes have a critical role in reducing the threat of AMR and improving treatment outcomes. To be successful AMS must be informed by up-to-date AMR surveillance data. As a profession it is timely for ophthalmology to act to prevent AMR leading to greater visual loss through supporting surveillance programmes and establishing AMS.

Microbial Keratitis Isolates at a Midwestern Tertiary Eye Care Center

PURPOSE

The aim of the study was to describe the pathogen, antimicrobial susceptibility, and trends over time of microbial keratitis (MK) at a Midwestern tertiary eye center.

METHODS

Patients with MK were identified in the electronic health record from August 2012 to December 2021. Diagnostic laboratory tests with an MK diagnosis were identified and classified as laboratory positive or laboratory negative. Laboratory-positive infections were categorized as bacterial (gram-positive, gram-negative, or acid-fast bacilli), fungal, viral, Acanthamoeba , or polymicrobial. Antimicrobial susceptibilities were obtained. Trends over time were assessed using linear regression.

RESULTS

Of 3288 patients with MK identified, 1012 (30.8%) had laboratory tests performed. Laboratory-positive infections (n = 499, 49.3%) were bacterial in 73.5% (n = 367) of cases, fungal in 7.8% (n = 39), viral in 1.6% (n = 8), Acanthamoeba in 1.4% (n = 7), and polymicrobial in 15.6% (n = 78). Of bacterial infections, 70% (n = 257) were gram-positive, with coagulase-negative Staphylococcus (CoNS; 31%) and Staphylococcus aureus ( S. aureus ; 23%) as the most common pathogens. Bacteria were acid-fast bacilli in 1.9% (n = 7) of cases and gram-negative in 28.1% (n = 103), with Pseudomonas aeruginosa as the predominant pathogen (47.7%). S. aureus showed antibiotic resistance from 0% (vancomycin and gentamicin) to 50% (erythromycin); CoNS from 0% (vancomycin, gentamicin, and moxifloxacin) to 64% (erythromycin). The rate of laboratory-negative MK significantly increased over time (slope estimate = 2.1% per year, P = 0.034). Rates of bacterial, fungal, viral, Acanthamoeba , and polymicrobial infections were stable over time (all slope P > 0.05).

CONCLUSIONS

Bacterial keratitis accounted for most MK cases. Gram-positive bacteria were the most common isolates. CoNS and S. aureus were universally susceptible to vancomycin. Rates of MK infection types were stable over time.

Managing Corneal Infections: Out with the old, in with the new?

There have been multiple reports of eye infections caused by antibiotic-resistant bacteria, with increasing evidence of ineffective treatment outcomes from existing therapies. With respect to corneal infections, the most commonly used antibiotics (fluoroquinolones, aminoglycosides, and cephalosporines) are demonstrating reduced efficacy against bacterial keratitis isolates. While traditional methods are losing efficacy, several novel technologies are under investigation, including light-based anti-infective technology with or without chemical substrates, phage therapy, and probiotics. Many of these methods show non-selective antimicrobial activity with potential development as broad-spectrum antimicrobial agents. Multiple preclinical studies and a limited number of clinical case studies have confirmed the efficacy of some of these novel methods. However, given the rapid evolution of corneal infections, their treatment requires rapid institution to limit the impact on vision and prevent complications such as scarring and corneal perforation. Given their rapid effects on microbial viability, light-based technologies seem particularly promising in this regard.

Corneal Culture and Antibiotic Susceptibility Results for Microbial Keratitis in the Mid-Atlantic Region of the United States, 2016 to 2020

OBJECTIVE

To examine the microbial distribution and antimicrobial susceptibility of culture-positive microbial keratitis at a large tertiary referral center in the mid-Atlantic region of the United States.

METHODS

Retrospective review of culture-positive microbial keratitis cases at the Wilmer Eye Institute from 2016 through 2020.

RESULTS

Of the 474 culture-positive microbial keratitis cases, most were bacterial (N=450, 94.9%), followed by fungal (N=48, 10.1%) and Acanthamoeba keratitis (N=15, 3.1%). Of the 450 bacterial isolates, 284 (69.5%) were gram-positive organisms, whereas 157 (28.4%) were gram-negative organisms. The most common bacterial species isolated was coagulase-negative Staphylococcus spp (N=154, 24.8%), and the most common gram-negative isolate was Pseudomonas aeruginosa (N=76, 12.3%). Among fungi, the most common isolates were Candida (N=25, 45.4%), whereas Fusarium (N=6, 10.9%) and Aspergillus (N=3, 5.5%) were less common. Of the 217 bacterial isolates tested for erythromycin susceptibility, 121 (55.7%; ∼60% of coagulase-negative staphylococci and corynebacteria tested) showed resistance to erythromycin.

CONCLUSIONS

Microbial keratitis in the Baltimore Mid-Atlantic region of the United States is most commonly caused by bacteria, with fungi and acanthamoeba being less common. Gram-positive bacterial infections predominate. Among fungal keratitis cases, Candida species are more commonly encountered than are filamentous species. Use of erythromycin as infection prophylaxis should be reexamined. Findings from our study may guide empiric treatment in this geographic region.

The microbiological landscape and epidemiology of ocular infections in a multi-tier ophthalmology network in India: an electronic medical record driven analytics report

OBJECTIVE

To study the epidemiology and landscape of ocular infections in patients undergoing microbiological investigations across a multi-tier ophthalmology network in India.

METHODS

This cross-sectional hospital-based study included 15,822 patients in whom microbiology samples were analysed between September 2013 and December 2021. Ocular tissue of patients in whom a microbiology sample was processed in at least one eye were included. The data were collected using an indigenously developed electronic medical record system.

RESULTS

Among the 15,822 patients, bacteria (51.06%) was the most common aetiology followed by fungus (38.27%). The majority of the patients were male (68.10%) and adults (90.01%). The most common age group was during the sixth decade of life with 2,914 (18.42%) patients. The patients were more commonly from the lower socio-economic status (51.61%) and from the rural geography (46.82%). Majority of the specimens sent for microbiological analysis were corneal scrapings (68.61%) followed by vitreous (8.77%). The most common bacteria isolated was Staphylococcus aureus (14.45%) followed by Pseudomonas aeruginosa (12.53%) and among the fungus were Fusarium (30.53%) and Aspergillus species (29.86%). Acanthamoeba (1.26%) and Microsporidia (0.38%) accounted for a minority of the infections in the samples. Fungus (53.10%; p ≤ 0.00001) and virus (51.08%; p = 0.000673) aetiology was found to be significantly higher in patients presenting from the rural geography.

CONCLUSION

The most common aetiology of infection in ocular disease is bacterial but fungal infections also accounted for a significant proportion. The majority of the patients with ocular infections presented from the rural geography and from lower socio-economic status.

Cutibacterium (Formerly Propionibacterium ) acnes Keratitis: A Review

ABSTRACT

Infectious keratitis is a devastating cause of vision loss worldwide. Cutibacterium acnes ( C. acnes ), a commensal bacterium of the skin and ocular surface, is an underrecognized but important cause of bacterial keratitis. This review presents the most comprehensive and up-to-date information for clinicians regarding the risk factors, incidence, diagnosis, management, and prognosis of C. acnes keratitis (CAK). Risk factors are similar to those of general bacterial keratitis and include contact lens use, past ocular surgery, and trauma. The incidence of CAK may be approximately 10%, ranging from 5% to 25% in growth-positive cultures. Accurate diagnosis requires anaerobic blood agar and a long incubation period (≥7 days). Typical clinical presentation includes small (<2 mm) ulcerations with deep stromal infiltrate causing an anterior chamber cell reaction. Small, peripheral lesions are usually resolved, and patients recover a high visual acuity. Severe infections causing VA of 20/200 or worse are common and often do not significantly improve even after treatment. Vancomycin is considered the most potent antibiotic against CAK, although other antibiotics such as moxifloxacin and ceftazidime are more commonly used as first-line treatment.

Epidemiological profile of microbial keratitis in Alexandria-Egypt a 5 years retrospective study

OBJECTIVE

To evaluate the epidemiologic profile of microbial keratitis in Alexandria- Egypt, with special emphasis on risk factors, visual outcome and microbiological results.

METHODS

This retrospective study reviewed files of patients treated for microbial keratitis during a period of 5 years at Alexandria Ophthalmology Hospital Cornea Clinic, Alexandria- Egypt, between February 2017 and June 2022. The patients were evaluated for the risk factors e.g., trauma, eyelid disorders, co-morbidities, and contact lens use. They were also evaluated for their clinical picture, the identified microorganisms, visual outcomes, and complications. Non-microbial keratitis and incomplete files were excluded from the study.

RESULTS

A total of 284 patients were diagnosed as microbial keratitis in our study. Viral keratitis was the most common cause of microbial keratitis (n = 118 (41.55%)), followed by bacterial keratitis (n = 77 (27.11%)), mixed keratitis (n = 51 (17.96%)), acanthamoeba keratitis (n = 22 (7.75%)) and the least cause was fungal keratitis (n = 16 (5.63%)). Trauma was the most common risk factor for microbial keratitis (29.2%). Fungal keratitis had a statistically significant association with trauma (p < 0.001), while the use of contact lenses had a statistically significant association with Acanthamoeba keratitis (p < 0.001). The percentage of culture-positive results in our study was 76.8%. Gram-positive bacteria were the most frequently isolated bacterial isolate (n = 25 (36.2%)), while filamentous fungi were the most frequently isolated fungi (n = 13(18.8%)). After treatment, there was a significant increase in the mean visual acuity among all groups; it was significantly higher in Acanthamoeba keratitis group with a mean difference of 0.262 ± 0.161 (p = 0.003).

CONCLUSION

Viral keratitis followed by bacterial keratitis were the most frequent etiologic agents causing microbial keratitis found in our study. Although trauma was the most frequent risk factor for microbial keratitis, contact lens wear was found an important preventable risk factor for microbial keratitis in young patients. Performing culture properly whenever indicated before starting antimicrobial treatment increased the cultures' positive results.

The epidemiology of infectious keratitis

Infectious keratitis is a rare but potentially severe sight-threatening disease, associated with considerable societal burden, cost and morbidity. This review summarises the most recent evidence for the incidence, risk factors and impact of disease, all of which vary widely according to region, access to health care, socioeconomic and environmental factors, predisposing conditions and causative organisms. The frequency and societal impact of infectious keratitis are significantly higher in low-income countries. In non-viral infectious keratitis, bacterial causes predominate in most regions. Fungi, particularly linked with agricultural trauma, are more frequently associated with infectious keratitis in low-income regions, particularly in India and certain African countries. The disease impact is compounded by poverty and limited access to services and treatment. Early diagnosis, access to appropriate treatment, prophylaxis in ocular trauma, availability of eye protection, awareness of risk factors may be associated with reduced disease severity and vision loss. Evidence for the incidence and burden of disease is lacking in certain regions and well-designed epidemiological studies to identify independent risk factors for the disease and those associated with more severe outcomes may better identify causation and guide resource allocation and preventative strategies.

Utility of investigation for suspected microbial keratitis: a diagnostic accuracy study

PURPOSE

The true disease status of a population with suspected microbial keratitis (MK) cannot be verified. There is not an accurate (gold) reference standard to confirm infection and inter-test comparisons of sensitivity and specificity therefore lead to bias with questionable estimates of test utility. We present an alternative method to report results.

METHODS

We used a decision to treat as the definition for MK. We retrospectively compared the results of corneal culture and polymerase chain reaction (PCR) as these are objective tests available for the three principal groups of pathogens. We then estimated the potential contribution of positive results, either alone or in combination, to support the working diagnosis.

RESULTS

We included 2021 (77.4%) eyes with suspected bacterial keratitis, 365 (14.0%) with suspected acanthamoeba keratitis, and 226 (8.6%) with suspected fungal keratitis, all treated between July 2013 and December 2019. In these groups, there were 51.6% positive culture and 6.5% positive PCR results for bacteria, 19.0% and 40.5% for acanthamoeba, and 28.3% and 15.0% for fungi. Between groups the differences in the proportions of positive results from culture and PCR was statistically significant (P < 0.001). The added benefit of PCR to the result of culture in identifying a potential pathogen was 1.4% for bacteria (P = 0.6292), 24.4% for acanthamoeba (P = 0.0001), and 5.8% for fungi (P = 0.3853).

CONCLUSIONS

For suspected MK a comparison of the test positivity rate is an easily comprehensible outcome measure of test utility.

Design and optimization of ciprofloxacin hydrochloride biodegradable 3D printed ocular inserts: Full factorial design and in-vitro and ex-vivo evaluations: Part II

Coupling hot-melt extrusion (HME) with fused deposition modeling three-dimensional printing (FDM-3DP) can facilitate the fabrication of tailored, patient-centered, and complex-shaped ocular dosage forms. We fabricated ciprofloxacin HCl ocular inserts by coupling high-throughput, solvent-free, and continuous HME with FDM-3DP. Insert fabrication utilized biocompatible, biodegradable, bioadhesive Klucel™ hydroxypropyl cellulose polymer, subjected to distinct FDM-3DP processing parameters, utilizing a design of experiment approach to achieve a tailored release profile. We determined the drug content, thermal properties, drug-excipient compatibility, surface morphology, in vitro release, antibacterial activity, ex-vivo transcorneal permeation, and stability of inserts. An inverse relationship was noted between insert thickness, infill density, and drug release rate. The optimized design demonstrated an amorphous solid dispersion with an extended-release profile over 24 h, no physical or chemical incompatibility, excellent mucoadhesive strength, smooth surface, lack of bacterial growth (Pseudomonas aeruginosa) in all release samples, and prolonged transcorneal drug flux compared with commercial eye drops and immediate-release inserts. The designed inserts were stable at room temperature considering drug content, thermal behavior, and release profile over three months. Overall, the fabricated insert could reduce administration frequency to once-daily dosing, affording a promising topical delivery platform with prolonged antibacterial activity and superior therapeutic outcomes for managing ocular bacterial infections.

Keeping an eye on the diabetic foot: The connection between diabetic eye disease and wound healing in the lower extremity

Diabetic eye disease is strongly associated with the development of diabetic foot ulcers (DFUs). DFUs are a common and significant complication of diabetes mellitus (DM) that arise from a combination of micro- and macrovascular compromise. Hyperglycemia and associated metabolic dysfunction in DM lead to impaired wound healing, immune dysregulation, peripheral vascular disease, and diabetic neuropathy that predisposes the lower extremities to repetitive injury and progressive tissue damage that may ultimately necessitate amputation. Diabetic retinopathy (DR) is caused by cumulative damage to the retinal mic-rovasculature from hyperglycemia and other diabetes-associated factors. The severity of DR is closely associated with the development of DFUs and the need for lower extremity revascularization procedures and/or amputation. Like the lower extremity, the eye may also suffer end-organ damage from macrovascular compromise in the form of cranial neuropathies that impair its motility, cause optic neuropathy, or result in partial or complete blindness. Additionally, poor perfusion of the eye can cause ischemic retinopathy leading to the development of proliferative diabetic retinopathy or neovascular glaucoma, both serious, vision-threatening conditions. Finally, diabetic corneal ulcers and DFUs share many aspects of impaired wound healing resulting from neurovascular, sensory, and immunologic compromise. Notably, alterations in serum biomarkers, such as hemoglobin A1c, ceruloplasmin, creatinine, low-density lipoprotein, and high-density lipoprotein, are associated with both DR and DFUs. Monitoring these parameters can aid in prognosticating long-term outcomes and shed light on shared pathogenic mechanisms that lead to end-organ damage. The frequent co-occurrence of diabetic eye and foot problems mandate that patients affected by either condition undergo reciprocal comprehensive eye and foot evaluations in addition to optimizing diabetes management.

Antibiotic susceptibility pattern of bacterial isolates from microbial keratitis in North and Central India: A multi centric study

Purpose

This study was conducted to examine microbiological profile with their antibiotic sensitivity in cases of bacterial keratitis in north and central India to ensure appropriate use of antibiotics.

Methods

The microbiology laboratory records of 228 patients with culture-proven bacterial keratitis from 1^st January to 31^st December 2019 were analyzed. Cultured bacterial isolates were subjected to antimicrobial susceptibility testing to antibiotics commonly used in the treatment of corneal ulcer. Chi-squared or Fisher's exact test were applied to check the significance of difference between the susceptibility levels of antibiotics.

Results

The prevalence of Staphylococcus aureus and Pseudomonas aeruginosa-induced keratitis was higher in northern India, whereas that by Streptococcus pneumoniae was more prevalent in central India. In central India, 100% of S. pneumoniae isolates were found to be sensitive to ceftriaxone compared to 79% in northern India (P = 0.017). In comparison to 67% of isolates from north India, 15% of S. aureus isolates from central India were found to be sensitive to ofloxacin (P = 0.009). Similarly, 23% of isolates from central India were found sensitive to amikacin compared to 65% of isolates from north India (P = 0.012). P. aeruginosa isolates from central India were found to be sensitive to ceftazidime in 63% of cases compared to 21% of isolates from north India (P = 0.034).

Conclusion

Prevalence of bacteria and their susceptibility to antibiotics are not uniform across geography. Vancomycin remained the most effective drug in all gram-positive coccal infections. S. aureus susceptibility to amikacin was significantly greater in north India. P. aeruginosa showed less susceptibility as compared to previous reports.

Comparison of culture, confocal microscopy and PCR in routine hospital use for microbial keratitis diagnosis

AIMS

To evaluate the sensitivity and specificity of polymerase chain reaction (PCR), in vivo confocal microscopy (IVCM) and culture for microbial keratitis (MK) diagnosis.

METHODS

Retrospective review of PCR, IVCM and culture results for MK diagnosis at Moorfields Eye Hospital between August 2013 and December 2014.

RESULTS

PCR results were available for 259 MK patients with concurrent culture for 203/259 and IVCM for 149/259. Sensitivities and specificities with 95% confidence intervals [95% CI] were calculated for Acanthamoeba keratitis (AK) and fungal keratitis (FK), by comparison with culture, for both IVCM and PCR. For AK, FK and bacterial keratitis (BK) sensitivities were calculated, for each diagnostic method, by comparison with a composite reference standard (a positive result for one or more of culture, PCR or IVCM having a specificity of 100% by definition). For the latter, sensitivities with [95% CI] were: for AK, IVCM 77.1% [62.7-88.0%], PCR 63.3% [48.3-76.6%], culture 35.6 [21.9-51.2]; for FK, IVCM 81.8% [48.2-97.7%], PCR 30.8% [9.09-61.4%], culture 41.7% [15.2-72.3%]; for BK, PCR 25.0% [14.7-37.9%], culture 95.6% [87.6-99.1%].

CONCLUSION

IVCM was the most sensitive technique for AK and FK diagnosis but culture remains our gold standard for BK. These findings reflect results to be expected from service providers to UK ophthalmology units and demonstrates the need at our centre for ongoing diagnostic result audit leading to the potential to improve PCR diagnosis. Both FK and AK are now common in the UK; ophthalmology units need to have all these techniques available to optimise their MK management.

Infectious Keratitis Isolates and Susceptibility in Southern California

PURPOSE

The purpose of this study was to determine longitudinal trends in prevalence and resistance profiles for infectious keratitis at referral centers in Southern California.

METHODS

Cultured infectious keratitis cases from January 1, 2006, through December 31, 2009, and January 1, 2016, through December 31, 2019, at the University of California, Los Angeles, were evaluated. Outcome measures included microbial isolate prevalence and antibiotic/antifungal susceptibility and resistance patterns.

RESULTS

One hundred thirty-nine and 315 culture-positive isolates were obtained between 2006-2009 and 2016-2019, respectively. Gram-positive organisms accounted for 65% (2006-2009) and 74% (2016-2019) of bacterial isolates ( P = 0.076). Staphylococcus infections, the most common gram-positive and bacterial isolate in both study epochs, demonstrated increased prevalence from 2006-2009 to 2016-2019 (41% vs. 53%, P = 0.019). Although coagulase-negative Staphylococcus (CoNS) increased from 40% to 58% ( P = 0.0012), the prevalence of methicillin-resistant Staphylococcus aureus was unchanged (28% vs. 28%, P = 0.99). Pseudomonas aeruginosa , the most common gram-negative organism, demonstrated decreased prevalence from 18% to 10% ( P = 0.027). Candida species comprised 3.5% of culture-positive isolates in both epochs. All gram-positive isolates were susceptible to vancomycin, and all Staphylococcus isolates were susceptible to linezolid. Pseudomonas aeruginosa remained susceptible to tested fluoroquinolones (>93%) and aminoglycosides (100%) over time.

CONCLUSIONS

In southern California between 2006 and 2019, there was a shift toward Staphylococcus species, with increased CoNS, decreased methicillin-sensitive Staphylococcus aureus , and decreased prevalence of P. aeruginosa . Empiric therapy of vancomycin and a fluoroquinolone or aminoglycoside provides effective antibacterial coverage for predominant bacterial species when culture sensitivities are pending.

Genomics of Staphylococcus aureus Strains Isolated from Infectious and Non-Infectious Ocular Conditions

Staphylococcus aureus is a major cause of ocular infectious (corneal infection or microbial keratitis (MK) and conjunctivitis) and non-infectious corneal infiltrative events (niCIE). Despite the significant morbidity associated with these conditions, there is very little data about specific virulence factors associated with the pathogenicity of ocular isolates. A set of 25 S. aureus infectious and niCIEs strains isolated from USA and Australia were selected for whole genome sequencing. Sequence types and clonal complexes of S. aureus strains were identified by using multi-locus sequence type (MLST). The presence or absence of 128 virulence genes was determined by using the virulence finder database (VFDB). Differences between infectious (MK + conjunctivitis) and niCIE isolates from USA and Australia for possession of virulence genes were assessed using the chi-square test. The most common sequence types found among ocular isolates were ST5, ST8 while the clonal complexes were CC30 and CC1. Virulence genes involved in adhesion (ebh, clfA, clfB, cna, sdrD, sdrE), immune evasion (chp, esaD, esaE, esxB, esxC, esxD), and serine protease enzymes (splA, splD, splE, splF) were more commonly observed in infectious strains (MK + conjunctivitis) than niCIE strains (p = 0.004). Toxin genes were present in half of infectious (49%, 25/51) and niCIE (51%, 26/51) strains. USA infectious isolates were significantly more likely to possess splC, yent1, set9, set11, set36, set38, set40, lukF-PV, and lukS-PV (p < 0.05) than Australian infectious isolates. MK USA strains were more likely to possesses yent1, set9, set11 than USA conjunctivitis strains (p = 0.04). Conversely USA conjunctivitis strains were more likely to possess set36 set38, set40, lukF-PV, lukS-PV (p = 0.03) than MK USA strains. The ocular strain set was then compared to 10 fully sequenced non-ocular S. aureus strains to identify differences between ocular and non-ocular isolates. Ocular isolates were significantly more likely to possess cna (p = 0.03), icaR (p = 0.01), sea (p = 0.001), set16 (p = 0.01), and set19 (p = 0.03). In contrast non-ocular isolates were more likely to possess icaD (p = 0.007), lukF-PV, lukS-PV (p = 0.01), selq (p = 0.01), set30 (p = 0.01), set32 (p = 0.02), and set36 (p = 0.02). The clones ST5, ST8, CC30, and CC1 among ocular isolates generally reflect circulating non-ocular pathogenic S. aureus strains. The higher rates of genes in infectious and ocular isolates suggest a potential role of these virulence factors in ocular diseases.

In vitro antimicrobial activity of ozonated oil in liposome eyedrop against multidrug-resistant bacteria

Bacteria are the most common causative agents of ocular infections. Treatment with topical broad-spectrum antibiotics is recommended in severe cases. However, antibiotic resistance has become a major concern in recent years, although antibiotics are generally effective in treating ocular infections. Antibacterial compound screening is performed to identify alternative therapeutic options to antibiotics. The aim of this study was to assess the in vitro antimicrobial activity of an ophthalmic solution containing ozonated oil. Strains of bacterial species with a multidrug resistance profile, which are responsible for a large proportion of ocular infections, were isolated and selected from different biological samples. The bacterial isolates were cultured, and ozonated oil was used to evaluate the inhibition zones at different time points. The treatment exhibited antibacterial activity against all the tested species. The effect was lower against the strains of Pseudomonas aeruginosa and more evident against Staphylococcus and Streptococcus spp. Our results suggest that the administration of ozonated oil may be a candidate agent to treat some infections of the ocular surface with a potential role in antimicrobial prophylaxis.

Microorganisms and Antibiotic Resistance of Bacterial Keratitis at a Rural County Hospital in Seville

PURPOSE

To review the incidence, resistance patterns, and management of bacterial keratitis during the past 4 years.

METHODS

We retrospectively reviewed the clinical records of microbiological isolates from patients with a clinical diagnosis of bacterial keratitis.

RESULTS

A total of 159 patients were analyzed, and 102 microorganisms were isolated from 129 cultures. In these cultures, 23.7% of the microorganisms were gram positive, 60.8% were gram negative, and 15.5% were fungi. Pseudomonas aeruginosa was the most common bacteria (9.2%), followed by Serratia marcescens (4.4%) and Staphylococcus aureus (4%). Resistance to fluoroquinolones and aminoglycosides was found to be 23.1% and 53.1% in gram-positive and 2.8% and 13.9% in gram-negative bacteria, respectively. Resistance to ceftazidime against gram-negative bacteria was 13.9%. No resistance to vancomycin was observed.

CONCLUSIONS

A high resistance rate to aminoglycosides and fluoroquinolones was observed in gram-positive bacteria. We concluded that fluoroquinolones or aminoglycosides may not be suitable for initial monotherapy in patients with severe bacterial keratitis.

Outcomes of Microbial Keratitis Cases Resistant to Antimicrobials in Sydney, Australia

PURPOSE

The purpose of this study was to describe demographics, predisposing factors, clinical features, treatment, and outcomes of microbial keratitis cases resistant to antimicrobials.

METHODS

A retrospective case series was conducted. All patients with microbial keratitis resistant to antimicrobials who underwent a corneal scrape and culture from 2012 to December 2016 at the Sydney Eye Hospital were included. Cases were identified from pathology and hospital coding data. Coagulase-negative staphylococci (CoNS), Staphylococcus aureus (S. aureus), and Corynebacterium spp. resistant to cefalotin, chloramphenicol, ciprofloxacin, or gentamicin were analyzed.

RESULTS

One hundred fifteen episodes had a resistant CoNS, 24 S. aureus, and 12 Corynebacterium spp. Antimicrobial resistance was associated with older women (67%, median age 83 years) with Corynebacterium spp. (P < 0.001), corneal graft, and previous topical steroid use. Larger epithelial defects (P = 0.203) and infiltrates (P = 0.180) were more likely to be associated with Corynebacterium spp., but not statistically significant. At the initial and final visits, resistant S. aureus (75% vs. 67%) and Corynebacterium spp. (78% vs. 80%) cases were more likely to be classified as blind (>3/60) compared with CoNS (45% vs. 28%) (P = 0.011 vs. P = 0.004). Corneal perforation occurred more often in resistant S. aureus cases (P < 0.001), whereas slow and nonhealing epithelial defects needing other procedures were more likely to occur with resistant Corynebacterium spp. (P < 0.001).

CONCLUSIONS

Patients with resistant CoNS were younger and presented with smaller ulcers and moderate vision loss. Visual and clinical outcomes were significantly better for resistant CoNS than for those with resistant S. aureus or Corynebacterium spp.

[Methicillin-resistant Staphylococcus epidermidis infectious keratitis: Clinical and microbiological profile]

Introduction

Staphylococcus epidermidis (SE) is a common cause of bacterial keratitis in certain geographic areas. A high percentage of resistance to methicillin is shown, which gives it cross resistance to beta-lactams and sometimes resistance to other antibacterial groups. We analyzed clinical and microbiological variables in patients with infectious keratitis due to SE.

Methods

Medical records of 43 patients with suspected infectious keratitis and microbiological confirmation for SE, between October 2017 and October 2020, were retrospectively studied. Clinical characteristics (risk factors, size of lesions, treatment, evolution) and microbiological (susceptibility to antibiotics) were analyzed, and groups of patients with methicillin-resistant (MRSE) and methicillin-susceptible (MSSE) infection were compared.

Results

MRSE was present in 37.2% of infectious keratitis. All isolates were sensitive to vancomycin and linezolid. Rates of resistance to tetracyclines and ciprofloxacin were 50% and 56% in the MRSE group, and 11% and 7% in the MSSE group. The clinical characteristics, including size of lesion, visual axis involvement, inflammation of anterior chamber, presence of risk factors and follow-up time, did not show statistically significant differences between groups.

Conclusions

MRSE is a common cause of infectious keratitis caused by SE and shows a high rate of multidrug resistance. Clinically, it does not differ from MSSE keratitis. Additional work is needed to confirm these findings.

Pathogens and Antibiotic Susceptibilities of Global Bacterial Keratitis: A Meta-Analysis

Bacterial keratitis (BK) is the most common type of infectious keratitis. The spectrum of pathogenic bacteria and their susceptibility to antibiotics varied with the different regions. A meta-analysis was conducted to review the global culture rate, distribution, current trends, and drug susceptibility of isolates from BK over the past 20 years (2000–2020). Four databases were searched, and published date was limited between 2000 and 2020. Main key words were “bacterial keratitis”, “culture results” and “drug resistance”. Forty-two studies from twenty-one countries (35 cities) were included for meta-analysis. The overall positive culture rate was 47% (95%CI, 42–52%). Gram-positive cocci were the major type of bacteria (62%), followed by Gram-negative bacilli (30%), Gram-positive bacilli (5%), and Gram-negative cocci (5%). Staphylococcus spp. (41.4%), Pseudomonas spp. (17.0%), Streptococcus spp. (13.1%), Corynebacterium spp. (6.6%) and Moraxella spp. (4.1%) were the most common bacterial organism. The antibiotic resistance pattern analysis revealed that most Gram-positive cocci were susceptive to aminoglycoside (86%), followed by fluoroquinolone (81%) and cephalosporin (79%). Gram-negative bacilli were most sensitive to cephalosporin (96%) and fluoroquinolones (96%), followed by aminoglycoside (92%). In Gram-positive cocci, the susceptibility trends of fluoroquinolones were decreasing since 2010. Clinics should pay attention to the changing trends of pathogen distribution and their drug resistance pattern and should diagnose and choose sensitive antibiotics based on local data.

A Systematic Review of Multi-decade Antibiotic Resistance Data for Ocular Bacterial Pathogens in the United States

INTRODUCTION

Since 2009, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study has been assessing in vitro antibiotic resistance for bacterial isolates sourced from ocular infections in the US. The main goal of this systematic review was to compare in vitro resistance data for ocular pathogens from published US studies with the most recently published data from the ARMOR study (2009-2018) and, where possible, to evaluate trends in bacterial resistance over time over all studies.

METHODS

A literature search was conducted using MEDLINE®, BIOSIS Previews®, and EMBASE^® databases (1/1/1995-6/30/2021). Data were extracted from relevant studies and antibiotic susceptibility rates for common ocular pathogens (Staphylococcus aureus, coagulase-negative staphylococci [CoNS], Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae), longitudinal changes in susceptibility, and multidrug resistance (MDR) were compared descriptively.

RESULTS

Thirty-two relevant studies were identified. High in vitro resistance was found among S. aureus and CoNS to fluoroquinolones, macrolides, and methicillin/oxacillin across studies, with high rates of MDR noted, specifically among methicillin-resistant staphylococci. Data from studies pre-dating or overlapping the early years of ARMOR reflected increasing rates of S. aureus resistance to fluoroquinolones, macrolides, methicillin/oxacillin, and aminoglycosides, while the ARMOR data suggested slight decreases in resistance to these classes between 2009 and 2018. Overall, methicillin-resistant S. aureus (MRSA) prevalence peaked from 2005 to 2015 with a possible decreasing trend in more recent years.

DISCUSSION AND CONCLUSIONS

Data from local and regional US datasets were generally consistent with data from the national ARMOR surveillance study. Continued surveillance of ocular bacterial pathogens is needed to track trends such as methicillin resistance and MDR prevalence and any new emerging antibiotic resistance phenotypes. Susceptibility data from ARMOR can inform initial choice of therapy, especially in practice areas where local antibiograms are unavailable.

Profile of Microbial Keratitis

Purpose: To study the demographic characteristics, predisposing factors, and latest trends of causative organisms and to analyze the prognostic factors of visual outcome in microbial keratitis.

Methods: A retrospective study of patients diagnosed with microbial keratitis who required hospital admission in the period between January 2018 and December 2020 in Taiping Hospital, Perak, Malaysia.

Results: A total of 75 eyes of 74 patients who were admitted to the hospital were studied. The male to female ratio was 13.8:1. Seventy percent of patients in this study were within the productive age group between 20 and 59 years old, with a mean age of 48 years old, and 51.4% of them were labourers. Cornea foreign bodies (42, 56%) were the most common predisposing factors and were associated with good visual outcomes (P<0.005). Other significant predictors for the final visual outcome were: presenting visual acuity, size of ulcer, duration of hospitalization, and duration of resolution. The mean duration of hospitalization was seven days. Corneal scrapings were done in all cases where 44 eyes (58.7%) were found to be positive for growth. Ten eyes (13.3%) that ended up with evisceration yielded a positive result. Gram-negative bacteria was the most prevalent causative organism of infective keratitis in the local/this region. Pseudomonas sp (20, 26.7%) being the most common bacterial isolate, was seen in all four contact lens-related cases and was associated with poor visual outcome and a high rate of evisceration. Patients who developed complications such as cornea melting (9, 12%), cornea perforation (11, 14.7%) and endophthalmitis (7, 9.3%) were associated with poor visual outcomes. Likewise, patients who required therapeutic interventions such as corneal gluing, tarsorrhaphy, and penetrating keratoplasty generally had poor visual outcomes (P<0.005; P=0.000008).

Conclusion: Microbial keratitis is a major cause of ocular morbidity globally. Understanding the demographic and epidemiological characteristics of microbial keratitis of the region is important in the initial prompt treatment of the patients and may eventually improve the visual outcome.

Double-masked, sham and placebo-controlled trial of corneal cross-linking and topical difluprednate in the treatment of bacterial keratitis: Steroids and Cross-linking for Ulcer Treatment Trial (SCUT II) study protocol

INTRODUCTION

Although antibiotics are successful at achieving microbiological cure in infectious keratitis, outcomes are often poor due to corneal scarring. Ideal treatment of corneal ulcers would address both the infection and the inflammation. Adjunctive topical steroid treatment may improve outcomes by reducing inflammation. Corneal cross-linking (CXL) is a novel prospective therapy that may simultaneously reduce both inflammatory cells and bacterial pathogens. The purpose of this study is to determine differences in 6-month visual acuity between standard medical therapy with antibiotics versus antibiotics with adjunctive early topical steroid therapy versus antibiotic treatment plus CXL and early topical steroids.

METHODS AND ANALYSIS

This international, randomised, sham and placebo-controlled, three-arm clinical trial randomises patients with smear positive bacterial ulcers in a 1:1:1 fashion to one of three treatment arms: (1) topical 0.5% moxifloxacin plus topical placebo plus sham CXL; (2) topical 0.5% moxifloxacin plus difluprednate 0.05% plus sham CXL; or (3) the CXL group: topical 0.5% moxifloxacin plus difluprednate 0.05% plus CXL.

ETHICS AND DISSEMINATION

We anticipate that both adjunctive topical steroids and CXL will improved best spectacle corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via ClinicalTrials.gov website, meetings and journal publications. Our data will also be available on reasonable request.

TRIAL REGISTRATION NUMBER

NCT04097730.

Susceptibility of Ocular Staphylococcus aureus to Antibiotics and Multipurpose Disinfecting Solutions

Staphylococcus aureus is a frequent cause of ocular surface infections worldwide. Of these surface infections, those involving the cornea (microbial keratitis) are most sight-threatening. S. aureus can also cause conjunctivitis and contact lens-related non-infectious corneal infiltrative events (niCIE). The aim of this study was to determine the rates of resistance of S. aureus isolates to antibiotics and disinfecting solutions from these different ocular surface conditions. In total, 63 S. aureus strains from the USA and Australia were evaluated; 14 were from niCIE, 26 from conjunctivitis, and 23 from microbial keratitis (MK). The minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of all the strains to ciprofloxacin, ceftazidime, oxacillin, gentamicin, vancomycin, chloramphenicol, azithromycin, and polymyxin B were determined. The MIC and MBC of the niCIE strains to contact lens multipurpose disinfectant solutions (MPDSs) was determined. All isolates were susceptible to vancomycin (100%). The susceptibility to other antibiotics decreased in the following order: gentamicin (98%), chloramphenicol (76%), oxacillin (74%), ciprofloxacin (46%), ceftazidime (11%), azithromycin (8%), and polymyxin B (8%). In total, 87% of all the isolates were multidrug resistant and 17% of the isolates from microbial keratitis were extensively drug resistant. The microbial keratitis strains from Australia were usually susceptible to ciprofloxacin (57% vs. 11%; p = 0.04) and oxacillin (93% vs. 11%; p = 0.02) compared to microbial keratitis isolates from the USA. Microbial keratitis isolates from the USA were less susceptible (55%) to chloramphenicol compared to conjunctivitis strains (95%; p = 0.01). Similarly, 75% of conjunctivitis strains from Australia were susceptible to chloramphenicol compared to 14% of microbial keratitis strains (p = 0.04). Most (93%) strains isolated from contact lens wearers were killed in 100% MPDS, except S. aureus 27. OPTI-FREE PureMoist was the most active MPDS against all strains with 35% of strains having an MIC ≤ 11.36%. There was a significant difference in susceptibility between OPTI-FREE PureMoist and Biotrue (p = 0.02). S. aureus non-infectious CIE strains were more susceptible to antibiotics than conjunctivitis strains and conjunctivitis strains were more susceptible than microbial keratitis strains. Microbial keratitis strains from Australia (isolated between 2006 and 2018) were more susceptible to antibiotics in comparison with microbial keratitis strains from the USA (isolated in 2004). Most of the strains were multidrug-resistant. There was variability in the susceptibility of contact lens isolates to MPDSs with one S. aureus strain, S. aureus 27, isolated from niCIE, in Australia in 1997 being highly resistant to all four MPDSs and three different types of antibiotics. Knowledge of the rates of resistance to antibiotics in different conditions and regions could help guide treatment of these diseases.

Infectious Keratitis After Boston Type 1 Keratoprosthesis Implantation

PURPOSE

To identify the incidence, risk factors, and outcomes of infectious keratitis after Boston type 1 keratoprosthesis (kpro) implantation.

METHODS

Retrospective case series of kpro procedures at the Stein Eye Institute and the Centre Hospitalier de l'Université de Montréal between May 1, 2004, and December 31, 2018. Data were collected regarding ocular history, operative details, postoperative management, microbiologic profile, treatment, and outcomes. Log-rank test and Cox proportional hazard ratio (HR) were used to evaluate for an association between risk factors and outcomes.

RESULTS

A total of 349 kpro procedures were performed in 295 eyes of 268 patients. Fifty-seven cases of presumed infectious keratitis were identified after 53 procedures (15.2%) in 50 eyes (16.9%) of 49 patients (18.3%). The incidences of culture-positive bacterial and fungal keratitis were 0.014 and 0.004 per eye-year, respectively. Persistent corneal epithelial defect formation (P < 0.001) and cicatricial disease (HR: 1.98, 95% confidence interval, 1.02-3.83) were associated with a significantly higher incidence of infectious keratitis. For the 53 cases with a known outcome, medical therapy achieved resolution of infection in 34 cases (64.2%), whereas kpro explantation was required in 19 cases (35.8%). Infectious keratitis was associated with an increased risk for kpro explantation (HR: 3.09, 95% confidence interval, 1.92-4.79).

CONCLUSIONS

Infectious keratitis develops in approximately 17% of eyes after kpro implantation, with a higher rate of culture-positive bacterial than fungal keratitis. The observed rate of microbial keratitis suggests the need for additional topical antimicrobial prophylaxis in eyes at higher risk, such as those with preexisting cicatricial disease or postoperative persistent corneal epithelial defect formation.

In Vitro Antibiotic Resistance among Bacteria from the Cornea in the Antibiotic Resistance Monitoring in Ocular MicRoorganisms Surveillance Study

PURPOSE

This study aimed to report on in vitro susceptibility patterns among corneal isolates collected in the Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) study.

METHODS

Each year, from 2009 to 2019, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates cultured from patients with ocular infections at participating ARMOR sites were submitted to a central laboratory for species confirmation and antibiotic susceptibility testing. In this analysis of corneal isolates, odds ratios for concurrent resistance were based on sample proportions, one-way ANOVA was used to evaluate resistance by patient age, and Cochran-Armitage tests were used to examine changes in antibiotic resistance over time.

RESULTS

A total of 1499 corneal isolates were collected from 61 sites over the 11-year period. Overall, 34.5% (148 of 429) of S. aureus and 41.9% (220 of 525) of CoNS isolates were methicillin resistant and had higher odds ratios for concurrent resistance to azithromycin (17.44 and 5.67), ciprofloxacin (39.63 and 12.81), and tobramycin (19.56 and 19.95), respectively, relative to methicillin-susceptible isolates (P < .001, all); also, a high proportion of methicillin-resistant S. aureus (85.1%) and methicillin-resistant CoNS (81.8%) were multidrug resistant (at least three classes of antibiotics). Resistance among S. pneumoniae isolates was highest for azithromycin (33.1%), whereas P. aeruginosa and H. influenzae isolates demonstrated low resistance overall. Among staphylococci, antibiotic resistance differed by patient age (S. aureus: F = 6.46, P < .001; CoNS: F = 4.82, P < .001), and few small changes in resistance (≤3.60% per year), mostly decreases, were observed over time.

CONCLUSIONS

Although rates of in vitro antibiotic resistance among presumed keratitis isolates obtained in ARMOR seemed stable between 2009 and 2019, resistance among staphylococci and pneumococci remains high (and should be considered when treating keratitis).

Development and optimization of hot-melt extruded moxifloxacin hydrochloride inserts, for ocular applications, using the design of experiments

The current study sought to formulate sustained-release hot-melt extruded (HME) ocular inserts of moxifloxacin hydrochloride (MOX; MOX-HME) for the treatment of bacterial keratitis. The concentration of Eudragit™ FS-100 (FS) and propylene glycol (PG) used as polymer and plasticizer, respectively, in the inserts were optimized using the central composite design (CCD) to achieve sustained release. The inserts were characterized for weight, thickness, surface characteristics, pH, and in vitro release profile. The crystalline characteristics of MOX and surface morphology of the inserts were evaluated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Furthermore, ex vivo permeation through rabbit cornea and stability of the optimized MOX-HME insert was investigated. The results demonstrate an inverse correlation between FS concentration and MOX release from the MOX-HME inserts, and a potential 24 h release. The optimized MOX-HME inserts were found to be stable at room temperature for four months, showing no significant change in drug content, pH and release profile. MOX converted into an amorphous form in the MOX-HME inserts and did not recrystallize during the study period. SEM analysis confirmed the smooth surface of the MOX-HME insert. The ex vivo studies revealed that the MOX-HME inserts provided a much prolonged transcorneal MOX flux as compared to the commercial ophthalmic solution and the immediate-release MOX-HME insert. The results indicate that MOX-HME inserts could potentially provide a once-a-day application, consequently reducing the dosing frequency and acting as an alternative delivery system in the management of bacterial infections.

Multidrug-Resistant Organisms from Ophthalmic Cultures: Antibiotic Resistance and Visual Acuity

INTRODUCTION

There is a growing trend of multidrug-resistant organisms (MDRO). The goal of this study was to characterize MDRO at a single center from ophthalmic cultures to better understand how treatments were tailored and to assess effect on visual acuity.

MATERIALS AND METHODS

The MDRO data were collected by the Multidrug-Resistant Organism Repository and Surveillance Network from the Brooke Army Medical Center clinical laboratory. Both patient- and isolate-specific data were collected and qualitatively analyzed. Primary outcome measures were organism and type of resistance, anatomic location of isolate, initial and final antibiotic choice, and visual acuity.

RESULTS

Thirty-one bacterial culture samples were analyzed from 29 patients. Twenty-two (72%) were Gram-positive and all were methicillin-resistant Staphylococcus aureus (MRSA). Nine (29%) were Gram-negative and of these five were Pseudomonas spp. Fourteen (45%) isolates were cultured from the cornea, nine (29%) from the lid, four (13%) from the conjunctiva, and four (13%) from other locations. The majority (66.6%) required adjustment of initial antibiotics following ocular culture results. Sixteen adult patients had recorded initial and final visual acuities. Fifteen of those 16 patients had stable or improved visual acuities following treatment of the infection, but five patients had a final visual acuity less than 20/200.

CONCLUSION

This study demonstrated a high frequency of corneal MDRO infections and specifically MRSA and Pseudomonas spp. isolates. Antibiotic treatments frequently required adjustment. Further prospective study of visual outcomes from ophthalmic MDRO cultures is needed.

Infectious keratitis: isolated microbes and their antibiotic susceptibility pattern during 2004-2014 in Region Örebro County, Sweden

PURPOSE

To describe predisposing risk factors, causative microorganisms and their antibiotic susceptibility patterns in infectious keratitis during an 11-year period in Region Örebro County, Sweden.

METHODS

This is a descriptive study conducted as a retrospective audit of clinical records. Patients who received treatment for infectious keratitis at any of the three ophthalmological departments within Region Örebro County, Sweden, between 2004 and 2014 were included if they fulfilled the predefined criteria for infectious keratitis. Data regarding culture results, antibiotic susceptibility pattern and risk factors for infectious keratitis were obtained from medical records and microbiological reports.

RESULTS

In total, 398 episodes of infectious keratitis in 392 patients were included, and 285 were culture positive. The most common predisposing risk factor was contact lens wear (45%). Coagulase-negative staphylococci (39.6%) was the most commonly isolated type of organism. Staphylococcus aureus (15.1%) followed by Moraxella spp. (7.4%) and Pseudomonas aeruginosa (6.7%) were among the most common isolated bacteria not considered to be commensal. Reduced susceptibility to fluoroquinolones was observed in five of 43 S. aureus isolates and in four of nine Streptococcus pneumoniae isolates.

CONCLUSION

The most common predisposing risk factor for keratitis was contact lens wear. Among the most common microbes, not considered to be exclusively commensals, isolated from the cornea in microbial keratitis were S. aureus, Moraxella spp. and P. aeruginosa. The antibiotic susceptibility patterns showed low proportion of resistance. Empiric treatment of suspected infectious keratitis with topical fluoroquinolones and chloramphenicol might be considered in a setting like ours pending culture results.

Etiology and Risk Factors for Infectious Keratitis in South Texas

Purpose

To determine the causative organisms and associated risk factors for infectious keratitis in South Texas.

Methods

This retrospective study was performed at a tertiary teaching hospital system in South Texas. Medical records of all patients who presented with infectious keratitis from 2012 to 2018 were reviewed. Only patients with culture-proven bacterial, fungal, and Acanthamoeba keratitis were included.

Results

In total, 182 eyes of 181 patients had culture-proven bacterial, fungal, or Acanthamoeba keratitis. The age of patients ranged from 3 to 93 years, with a mean of 48.3 ± 20.8 years. The most common etiologic agent was bacteria, with 173 bacterial cultures (95.1%) recovered, followed by 13 fungal cultures (7.1%), and 3 Acanthamoeba cultures (1.6%). Of the 218 bacterial isolates, coagulase-negative Staphylococcus was the most common (25.7%), followed by Pseudomonas aeruginosa (23.4%), Staphylococcus aureus (11.0%), and Moraxella (7.8%). Fusarium was the most common fungal isolate (46.2%). The most common risk factors for infectious keratitis included contact lens wear (32.4%), underlying corneal disease (17.6%), trauma (14.3%), and ocular surface disease (13.7%).

Conclusions

Bacteria are the most common cause of infectious keratitis in this patient population, with coagulase-negative Staphylococcus and Pseudomonas as the most common isolates. The prevalence of culture-positive fungal keratitis is significantly lower than that of bacterial keratitis. Contact lens wear is the most common risk factor associated with infectious keratitis in South Texas.

Bacterial etiology and antimicrobial resistance trends in ocular infections: A 30-year study, Turin area, Italy

PURPOSE

Bacterial ocular infections can result in loss of all or part of the ocular structures, contributing to a high disability charge. Local surveillance of etiology and susceptibility patterns is crucial for an appropriate empiric management of ocular infections. The aim of this study was to analyze of bacterial spectrum in culture-proven ocular infections and trends of antimicrobial susceptibility patterns.

METHODS

A monocentric retrospective study was performed including ocular infection cases diagnosed at the Microbiology Unit of Turin Ophthalmic Hospital between 1988 and 2017. Spectrum of pathogens that caused bacterial culture-proven ocular infections and trends of antimicrobial susceptibility patterns were analyzed.

RESULTS

A total of 15,517 culture-positive isolates were identified as causative agents of ocular infections. Gram-positive bacteria were deemed to cause infection in 73.5% of cases. Staphylococcus spp. and Pseudomonas spp., coagulase-negative staphylococci, Staphylococcus aureus were the leading causative pathogens of keratitis, endophthalmitis, and conjunctivitis, respectively. Statistically significant changes in temporal trends were observed for all analyzed microorganism groups except for Enterobacteriaceae group. Overall, fluoroquinolones and chloramphenicol demonstrated to be the most effective antimicrobials in vitro toward bacterial ocular infections, followed by tetracycline, ampicillin, and aminoglycosides. Enterobacteriaceae isolates showed higher multi-drug resistance rate, followed by coagulase-negative staphylococci. Analysis of resistance rates over time highlighted increasing resistance trend for aminoglycosides among Gram-negative and for both aminoglycosides and fluoroquinolones among Gram-positive pathogens, especially for S. aureus.

CONCLUSION

This study provided a 30-year assessment of bacterial ocular infections in an urban area of Italy, giving support to epidemiological consciousness and guiding empiric antimicrobial therapy.

Antimicrobial resistance trends in bacterial keratitis over 5 years in Sydney, Australia

IMPORTANCE

Antimicrobial resistance (AMR) patterns in bacterial keratitis may fluctuate in a geographic location over time.

BACKGROUND

To investigate any change in AMR patterns in Sydney, Australia.

DESIGN

Retrospective case series.

PARTICIPANTS

All patients with microbial keratitis who underwent a corneal scrape and culture from 2012 to 2016 at the Sydney Eye Hospital.

METHODS

Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry identified organisms. The Calibrated Dichotomous Susceptibility method determined antibiotic susceptibilities.

MAIN OUTCOME MEASURES

Isolated organisms and antibiotic susceptibilities.

RESULTS

There were 1084 corneal scrapes from 957 patients. The mean age was 54 years (range 18-100) and 52% were male. Cultures were positive in 711 of 1084 scrapes (66%), with 884 organisms identified. Of the bacteria isolated, 685 of 884 (78%) were Gram-positive and 199 of 884 (22%) were Gram-negative. Overall, the most common bacteria were coagulase-negative Staphylococci (CoNS) (405/884, 46%). Methicillin-resistance was detected in 7% of Staphylococcus aureus isolates (7/103). Methicillin-resistance in CoNS (ie, also cefalotin resistance) was reported in 19% of isolates and ciprofloxacin 8%. For methicillin-sensitive S aureus (MSSA), 5% of isolates were resistant to ciprofloxacin. For Corynebacterium spp., 34% of isolates were resistant to chloramphenicol and 9% to ciprofloxacin. The most common Gram-negative bacteria was Pseudomonas aeruginosa (109/199, 55%). One case was resistant to ciprofloxacin.

CONCLUSIONS AND RELEVANCE

Coagulase-negative staphylococcal species were the most frequently suspected of causing bacterial keratitis. Increased resistance to cefalotin was identified for CoNS and to ciprofloxacin for Corynebacterium spp., MSSA and P aeruginosa compared to a previous study in Sydney in 2002 to 2003.

Microbial Keratitis in Taiwan: A 20-Year Update

PURPOSE

To investigate the demographics, risk factors, microbiology, and resistance pattern at a tertiary hospital and to detect the shifting trend over 2 decades.

DESIGN

A retrospective observational case series.

METHODS

We reviewed all records of patients with microbial keratitis (MK) that were hospitalized in National Taiwan University Hospital between 2007 and 2016. Demographics, predisposing factors, pathogens, and clinical courses were compared to our previous study conducted from 1992 to 2001. Antibiotic susceptibility was compared with those conducted from 1994 to 2005.

RESULTS

The percentage of patients 60 years and older in the MK population was increasing (P = 2.1E-21). The proportion of trauma-related MK declined while MK related to chronic ocular or systemic disorders rose. The prevalence of nontuberculous mycobacteria (NTM) showed a decreasing trend (P = .0032), whereas Microsporidia has been increasingly detected. The 2 most common bacterial isolates were Pseudomonas aeruginosa (35.2%) and Staphylococcus species (13.2%). Management of these infection did not differ in common pathogens between the 2 decades. The susceptibility of Staphylococcus species to oxacillin reduced significantly (P = .002) and there was an increase in methicillin-resistant Staphylococcus aureus keratitis.

CONCLUSIONS

Contact lens wear remained the most common predisposing factor, with Pseudomonas species as the major pathogen. However, chronic disorder-related MK was on the rise along with an increasing trend of oxacillin resistance in Staphylococcus species. We found a decreasing trend in NTM keratitis while Microsporidia keratitis was considered as an emerging ocular disease. Though gram-negative isolates remained susceptible to all antibiotics tested, antibiotic resistance was more common in gram-positive isolates.

Laboratory Results, Epidemiologic Features, and Outcome Analyses of Microbial Keratitis: A 15-Year Review From St. Louis

PURPOSE

To evaluate the laboratory results and prognostic factors of poor clinical outcomes in microbial keratitis cases over 15 years at Saint Louis University.

DESIGN

Retrospective cohort and trend study.

METHODS

Microbiological and clinical information from culture-positive cases seen at Saint Louis University from 1999 to 2013 were reviewed retrospectively. Statistical analyses were used to determine microbiological and antibiotic susceptibility trends. Prognostic factors of poor clinical outcome from the literature were used to create multivariate regression models to describe our cohort.

RESULTS

Gram-positive organisms predominated (48%), followed by gram-negative organisms (34%) and fungi (16%). The most commonly isolated organism was Pseudomonas aeruginosa (21%). Oxacillin-resistant rates of Staphylococcus aureus and coagulase-negative staphylococci were 45% and 43%, respectively. Only the proportion of Pseudomonas changed significantly over time (P = .02). The only antibiotic found to lose efficacy over time was gentamicin for gram-positive organisms (P = .005). Multivariate logistic regression analyses revealed that major complications were associated with large ulcers (P < .006), fungal cases (P < .001), and comorbid ophthalmic conditions (P < .001). Poor healing was associated with large ulcers (P < .001) and fungal cases (P < .001). Lastly, poor visual outcome was associated with large ulcers (P < .01) and age ≥ 60 years (P < .02).

CONCLUSIONS

In the St Louis area, oxacillin-resistant organisms, Pseudomonas aeruginosa, and fungi are commonly recovered from microbial keratitis cases with a disproportionally high incidence. Hence, empiric antibiotic choice should reflect these trends. Special care needs to be taken for patients with large ulcers and fungal infections, as well as elderly patients with comorbid ophthalmic conditions, as these patients have worse clinical outcomes.

Epidemiology and Outcome of Microbial Keratitis: Private University Versus Urban Public Hospital Care

PURPOSE

To review the epidemiology, risk factors, microbiologic spectrum, and treatment of microbial keratitis during a 5-year period at an urban public hospital in comparison with an adjacent private university practice.

METHODS

Retrospective chart review in the 5-year interval, 2009 through 2014. Primary outcome measures included patient age at presentation, best-corrected visual acuity (BCVA), risk factors, culture and sensitivities, treatment, and complication occurrence.

RESULTS

A total of 528 eyes with microbial keratitis were identified, 318 in the public cohort and 210 in the private cohort. Contact lens wear was the most common risk factor in the public cohort, whereas ocular surface disease was the most common risk factor in the private cohort. Gram-positive organisms represented 47.3%, gram-negative organisms 32.1%, fungal organisms 13.6%, and Acanthamoeba 6.4% of corneal isolates. Gentamicin resistance was 4.4% and tobramycin resistance was 2.9%. The inpatient treatment rate of the public cohort was 40% compared with 4% in the private cohort. In the public cohort, average BCVA at resolution was 20/82 (log of minimal angle of resolution [logMAR] 0.61). For the private cohort, average BCVA at resolution was 20/73 [logMAR, 0.56]. The perforation rate was 8% in the public cohort compared with 4% in the private cohort. Six percent of cases underwent urgent penetrating keratoplasty in the public cohort versus 2% in the private cohort.

CONCLUSIONS

Microbial keratitis remains a clinical challenge in the urban public hospital setting. The risk profile of patients presenting in the public hospital setting may be different from patients presenting in a private care setting. Public hospital patients may present later in the course of their infection and thus have a higher rate of complications regardless of effective antimicrobial therapy.

Keratitis antimicrobial resistance surveillance program, Sydney, Australia: 2016 Annual Report

IMPORTANCE

Antimicrobial resistance data from bacterial keratitis in Australia are lacking.

BACKGROUND

Antimicrobial resistance is a global health threat. Bacterial keratitis is an ophthalmic emergency requiring immediate and effective treatment.

DESIGN

Retrospective cohort study of bacterial isolates and antibiotic susceptibility profiles at a quaternary hospital in Sydney, Australia.

PARTICIPANTS

Two hundred and twenty-four corneal scrapes from patients from January 1 to December 31, 2016.

METHODS

Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry identified bacteria. The Calibrated Dichotomous Sensitivity (CDS) method determined antibiotic susceptibilities.

MAIN OUTCOME MEASURES

Isolated organisms and antibiotic susceptibilities.

RESULTS

One hundred and sixty-eight scrapes of 224 (75%) were culture positive. One hundred and thirty-one patients had a single organism isolated and 21 had mixed bacterial growth. Of the 157 organisms isolated, 131 (83%) were Gram-positive and 27 (17%) Gram-negative. Of the Gram-positive organisms, 75 (57%) were coagulase-negative Staphylococci (CoNS), 15 (11%) Staphylococcus aureus (including one methicillin-resistant Staphylococcus aureus [MRSA]) and 8 (6%) Corynebacterium spp. Of the Gram-negative organisms, 15 (58%) were Pseudomonas aeruginosa. With methicillin-sensitive Staphylococcus aureus (MSSA) resistance to chloramphenicol was 21%, ciprofloxacin 7% and gentamicin 7%. With CoNS resistance to cefalotin was 9%, gentamicin 9% and ciprofloxacin 9%. With Corynebacterium spp. resistance was 40% to cefalotin, chloramphenicol 25% and ciprofloxacin 14%.

CONCLUSIONS AND RELEVANCE

Staphyloccocus spp. and Pseudomonas spp. were the most common microorganisms isolated. There was low resistance to cefalotin and ciprofloxacin for these isolates. More than 90% of these would be covered by current therapeutic recommendations for empiric therapy in Australia.

Bacterial Keratitis in Toronto: A 16-Year Review of the Microorganisms Isolated and the Resistance Patterns Observed

PURPOSE

To review the incidence, distribution, current trends, and resistance patterns of bacterial keratitis isolates in Toronto over the past 16 years.

METHODS

Microbiology records of suspected bacterial keratitis that underwent a diagnostic corneal scraping and cultures from January 1, 2000, through December 31, 2015, were retrospectively reviewed. The distribution of the main isolated pathogens and in vitro laboratory minimum inhibitory concentration testing results were used to identify resistance patterns.

RESULTS

A total of 2330 corneal scrapings were taken over 16 years. A pathogen was recovered in 1335 samples (57.3%), with bacterial keratitis accounting for 1189 of the positive cultures (86.0% of all isolates). The total number of gram-positive and gram-negative isolates was 963 and 324, respectively. Coagulase-negative Staphylococcus and Pseudomonas aeruginosa were the most common gram-positive and gram-negative bacteria isolates, respectively. A decreasing trend in the number of isolates in gram-positive bacteria (P = 0.01), specifically among Staphylococcus aureus (P < 0.0001) and Streptococcus species (P = 0.005), was identified. When analyzing the susceptibilities of gram-positive and gram-negative isolates, an increasing trend in antibiotic resistance was observed in erythromycin (P = 0.018), ceftazidime (P = 0.046), and piperacillin/tazobactam (P = 0.005). The susceptibility of tested gram-positive microorganisms to vancomycin was 99.6%.

CONCLUSIONS

There has been a decreasing trend in the number of isolates in gram-positive microorganisms over the past 16 years. An increasing trend in resistance for various antibiotics against gram-negative and gram-positive isolates was identified. High susceptibility to vancomycin reinforced the empirical use of fortified tobramycin and vancomycin in the initial management of severe bacterial keratitis.

Bacterial Keratitis: Isolated Organisms and Antibiotic Resistance Patterns in San Francisco

PURPOSE

Understanding the spectrum of pathogens in a given geographic region is important when deciding on empiric antibiotic therapy. In this study, we evaluate the spectrum of bacterial organisms cultured from corneal samples and their antibiotic sensitivities to guide initial treatment of keratitis.

METHODS

We performed a retrospective case review of cultures from suspected infectious keratitis cases at the Francis I. Proctor Foundation, University of California, San Francisco, from 1996 through 2015. Logistic regression models were used to assess the risk of culturing methicillin-resistant Staphylococcus aureus (MRSA) from ulcers over time and the association between the year cultured and moxifloxacin resistance.

RESULTS

A total of 522 of 2203 (23.7%) cultures grew bacterial organisms believed to be the etiology of infection, with available antibiotic sensitivity data. Of these, 338 (65.3%) grew gram-positive organisms with the most common being methicillin-sensitive Staphylococcus aureus (20.1%, N = 105). One hundred eighty (34.7%) grew gram-negative species with Pseudomonas aeruginosa as the most prevalent organism (10.9%, N = 57). There was 1.13 increased odds of culturing MRSA for each 1-year increase in the culture date (P = 0.01) and 1.26 increased odds of culturing an organism resistant to moxifloxacin with each 1-year increase in the culture date after controlling for the infectious organism (P < 0.001).

CONCLUSIONS

Gram-positive organisms are the most commonly identified etiology of microbial keratitis in this series. Approximately 35% of cultured organisms had variable susceptibility to moxifloxacin, and resistance seems to be increasing over time. The risk of culturing MRSA increased over time.

The epidemiology of nonviral microbial keratitis in a tertiary care center in Muscat, Oman

OBJECTIVE:

The objective of this study is to describe the epidemiology, risk factors, etiology, and outcome of microbial keratitis in a tertiary care center in Muscat, Oman.

METHODS:

The electronic records of all patients diagnosed with keratitis or corneal ulcer between January 2013 and January 2016 in Al-Nahdha Hospital were retrospectively reviewed. Patients who presented with a corneal ulcer requiring admission and who underwent culture and sensitivity studies were included in the study. Patients with viral keratitis or sterile corneal ulcers were excluded from the study.

RESULTS:

A total of 606 electronic medical records of all presumed microbial keratitis were reviewed. Out of these, 304 met the eligibility criteria. The mean age of patients was 52.2 years (standard deviation [SD]: ±23.2 years; range: 0.1–89 years). A total of 198 (65%) microbial cultures yielded positive results. Of these, 182 (92%) were bacterial, 13 (7%) were fungal, and 3 (1%) cases were due to a combined (bacterial and fungal) etiology. Gram-positive bacteria accounted for 102 (55.1%), of which the majority was due to Streptococcus pneumoniae. Gram-negative bacteria accounted for 77 (41.6%) cases; half were caused by Pseudomonas aeruginosa. Keratitis in patients aged 18 years and younger was more likely to be associated with trauma (48.3%, P < 0.001) in young adults with contact lens wear (64%, P < 0.001) and in adults over 40 years with blepharitis (55.6%), sequelae of previous trachoma infection (26.3%), and eyelid abnormalities (18.4%). Following recovery, corneal scarring was seen in 63.2% of patients.

CONCLUSION:

Microbial keratitis affects patients of all age groups but is more common in older adults. The vast majority of culture-proven cases are due to bacterial infections. Children and teenagers are more likely to develop keratitis following eye trauma whereas young adults mostly develop the condition in association with contact lens wear. Ocular surface disease is the most important risk factor in older adults. The majority of patients end up with corneal scarring.

Retrospective report of antimicrobial susceptibility observed in bacterial pathogens isolated from ocular samples at Mount Sinai Hospital, 2010 to 2015

BACKGROUND

Antimicrobial resistance has emerged as a major threat to global public health. Thus, the surveillance of changes in antimicrobial resistance in local and global settings is a paramount necessity. While many studies have tracked antimicrobial resistance, only a small percentage surveyed ocular isolates. The purpose of this study was to report the in vitro susceptibility of bacterial pathogens isolated from ocular samples in New York, NY from 2010 to 2015.

METHODS

A retrospective review of ocular isolates was conducted. All organisms were collected by 25 separate inpatient wards and outpatient clinics, and were analyzed by the clinical microbiology laboratory at Mount Sinai Hospital. Clinical Laboratory and Standards Institute (CLSI) guidelines were followed for susceptibility testing and breakpoint interpretations.

RESULTS

A total of 549 bacterial organisms were isolated from 1664 cultures (33%) during the 6-year study period. Of these, 358 isolates (65.2%) underwent susceptibility testing. 182 (50.8%) isolates were Gram-positive. The most common Gram-positive bacterium was Staphylococcus aureus (62.1%). Methicillin-resistance decreased in S. aureus isolates (31.3% in 2010, 14.1% in 2015) but was without significant change (p = 0.25). When analyzing all S. aureus isolates recovered during the study period, there were significantly more methicillin-resistant S. aureus (MRSA) isolates resistant to fluoroquinolones (p <0.0001), erythromycin (p <0.0001), and trimethoprim/sulfamethoxazole (TMP/SMZ; p <0.05). Overall, Streptococcus pneumoniae isolates showed reduced susceptibility to erythromycin, but were otherwise susceptible to the other antimicrobials tested. Haemophilus influenzae (26.1%) and Pseudomonas aeruginosa (23.9%) were the most common Gram-negative bacteria isolated. Resistance to ampicillin and TMP/SMZ was observed in several of the H. influenzae isolates. P. aeruginosa isolates did not show high resistance overall, however, it was noted that isolates resistant to meropenem were also resistant to other antimicrobials (p < 0.01).

CONCLUSION

Overall, antimicrobial resistance was infrequent for the Gram-negative and Gram-positive bacteria analyzed. While the MRSA isolates demonstrated increased resistance to multiple antimicrobial classes, this is expected for this pathogen. Due to the continued use of broad-spectrum oral and systemic antimicrobials to treat ocular infections, findings of this study and other surveillance studies specific to ocular isolates should be used as resources in effective decision making in the treatment of ocular disease.

Trends of Bacterial Keratitis Culture Isolates in Jerusalem; a 13- Years Analysis

PURPOSE

To describe the trends in pathogens and antibacterial resistance of corneal culture isolates in infectious keratitis during a period of 13 years at Hadassah-Hebrew University Medical Center.

METHODS

A Retrospective analysis of bacterial corneal isolates was performed during the months of January 2002 to December 2014 at Hadassah Hebrew University Medical Center. Demographics, microbiological data and antibiotic resistance and sensitivity were collected.

RESULTS

A total of 943 corneal isolates were analyzed during a 13 year period. A total of 415 positive bacterial cultures and 37 positive fungal cultures were recovered, representing 48% of the total cultures. The Annual incidence was 34.78 ± 6.54 cases. The most common isolate was coagulase-negative staphylococcus (32%), which had a significant decrease in trend throughout the study period (APC = -8.1, p = 0.002). Methicillin-resistant Staphylococcus aureus (MRSA) appears to have a decrease trend (APC = -31.2, P = 0.5). There was an increase in the resistance trend of coagulase-negative staphylococci to penicillin (APC = 5.0, P = <0.001). None of the pathogens had developed any resistance to Vancomycin. (P = 0.88).

CONCLUSIONS

Coagulase negative staphylococci were the predominant bacteria isolated from patients with keratitis. There was no significant change in the annual incidence of cases of bacterial keratitis seen over the past 13 years. Keratitis caused by MRSA appeared to decrease in contrast to the reported literature.