Late bacterial and fungal keratitis after corneal transplantation. Spectrum of pathogens, graft survival, and visual prognosis

Nanoparticle-hydrogel composite as dual-drug delivery system for the potential application of corneal graft rejection

Immune rejection remains the major cause of corneal graft failure. Immunosuppressants (such as rapamycin; RAPA) adjunctive to antibiotics (such as levofloxacin hydrochloride; Lev) are a clinical mainstay after corneal grafts but suffer from poor ocular bioavailability associated with severe side effects. In this study, we fabricated a Lev@RAPA micelle loaded cationic peptide-based hydrogel (NapFFKK) as a dual-drug delivery system by integrating RAPA micelles with Lev into a cationic NapFFKK hydrogel to potentially reduced the risk of corneal graft rejection. The properties of the resulting hydrogels were characterized using transmission electronmicroscopy and rheometer. Lev@RAPA micelles loaded NapFFKK hydrogel provided sustained in vitro drug release without compromising their inherent pharmacological activities. Topical instillation of Lev@RAPA micelles loaded NapFFKK hydrogel resulted in the great ocular tolerance and extended precorneal retention over 60 min, thus significantly enhancing the ocular bioavailability of both Lev and RAPA. Overall, such dual-drug delivery system might be a promising formulation for the suppression of corneal graft failure.

Post-Keratoplasty Microbial Keratitis in the Era of Lamellar Transplants-A Comprehensive Review

Microbial keratitis in a post-transplant cornea should be considered a distinct entity from microbial keratitis in a non-transplant cornea. Firstly, the use of immunosuppressive treatments and sutures in corneal transplants changes the etiology of keratitis. Secondly, corneal transplant has an impact on corneal biomechanics and structure, which facilitates the spread of infection. Finally, the emergence of lamellar transplants has introduced a new form of keratitis known as interface keratitis. Given these factors, there is a clear need to update our understanding of and management strategies for microbial keratitis following corneal transplantation, especially in the era of lamellar transplants. To address this, a comprehensive review is provided, covering the incidence, risk factors, causes, and timing of microbial keratitis, as well as both clinical and surgical management approaches for its treatment in cases of penetrating and lamellar corneal transplants.

Analysis in Results of Microbiologic Exam Related to Donor Corneas

Purpose: This study analyzed the microorganisms identified in donor corneas and their clinical significance.Methods: The medical records of 94 patients (114 eyes) who underwent keratoplasty and microbiological tests of the donor corneas from October 2008 to December 2020 at our hospital were reviewed retrospectively. During keratoplasty, we conducted microbiological tests of the corneoscleral rim of the donor cornea and preserving solution Optisol™-GS (Bausch & Lomb, Rochester, NY, USA), and examined the antibiotic susceptibility of bacterial isolates from the cultures.Results: Some isolates of domestic donor corneas revealed bacteria, but none of the imported corneas did. Gram-negative bacilli were detected from the corneoscleral rim in three eyes (2.6%): two cases of Acinetobacter baumannii/haemolyticus and one case of Pseudomonas aeruginosa. In one case (0.9%), Acinetobacter baumannii/haemolyticus was identified from preserving solution, with no bacteria found in the corneoscleral rim. Antibiotic susceptibility tests showed multi-drug resistance, except to colistin. In all cases where bacteria were detected, there was no keratitis or endophthalmitis after corneal transplantation.Conclusions: Although rare, bacteria can be identified from donor corneas or the preserving solution used in corneal transplantation. Therefore, caution is needed in all processes dealing with donor corneas. Empirical antibiotics that have sufficient antimicrobial activity to suppress multi-drug resistant bacteria should be selected in corneal transplantation.

Update on Suture Techniques in Corneal Transplantation: A Systematic Review

Effective suturing remains key to achieving successful outcomes in corneal surgery, especially anterior lamellar keratoplasty and full thickness transplantation. Limitations in the technique may result in complications such as wound leak, infection, or high astigmatism post corneal graft. By using a systematic approach, this study reviews articles and conducts content analysis based on update 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria). The aim of this paper is to summarize the state of the art of corneal suturing techniques for every type of corneal transplant and patient age and also their outcomes regarding astigmatism and complications. Future developments for corneal transplantation will be also discussed. This is important because especially the young surgeon must have knowledge of the implications of every suture performed in order to achieve consistent and predictable post-operative outcomes and also be aware of all the possible complications.

Post-keratoplasty Infectious Keratitis: Epidemiology, Risk Factors, Management, and Outcomes

Post-keratoplasty infectious keratitis (PKIK) represents a unique clinical entity that often poses significant diagnostic and therapeutic challenges. It carries a high risk of serious complications such as graft rejection and failure, and less commonly endophthalmitis. Topical corticosteroids are often required to reduce the risk of graft rejection but their use in PKIK may act as a double-edged sword, particularly in fungal infection. The increased uptake in lamellar keratoplasty in the recent years has also led to complications such as graft-host interface infectious keratitis (IIK), which is particularly difficult to manage. The reported incidence of PKIK differs considerably across different countries, with a higher incidence observed in developing countries (9.2-11.9%) than developed countries (0.02-7.9%). Common risk factors for PKIK include the use of topical corticosteroids, suture-related problems, ocular surface diseases and previous corneal infection. PKIK after penetrating keratoplasty or (deep) anterior lamellar keratoplasty is most commonly caused by ocular surface commensals, particularly Gramme-positive bacteria, whereas PKIK after endothelial keratoplasty is usually caused by Candida spp. Empirical broad-spectrum antimicrobial treatment is the mainstay of treatment for both PKIK, though surgical interventions are required in medically refractory cases (during the acute phase) and those affected by visually significant scarring (during the late phase). In this paper, we aim to provide a comprehensive overview on PKIK, encompassing the epidemiology, risk factors, causes, management and outcomes, and to propose a treatment algorithm for systematically managing this challenging condition.

Microbial keratitis and clinical outcomes following penetrating and endothelial keratoplasty

PURPOSE

The goal of this study was to review the incidence, risk factors and outcomes of microbial keratitis after penetrating keratoplasty (PK) and endothelial keratoplasty (EK).

METHODS

The electronic medical records at Wills Eye Hospital were queried for cases of microbial keratitis following PK or EK performed between 1 May 2007 and 1 September 2018. Charts were reviewed to obtain demographic data, transplant characteristics, details of microbial keratitis, graft survival and clinical outcomes.

RESULTS

During the study period, 2098 transplants were performed in 1601 patients. Of these, 1267 (60.4%) were PKs and 831 (39.6%) were EKs. We identified 86 (4.1%) cases of subsequent microbial keratitis. The incidence of microbial keratitis after PK was significantly higher than after EK (5.9% versus 1.3%; p = 0.005). Furthermore, the rate of infection was higher after repeat transplants (either PK or EK) compared to initial keratoplasties (5.5% versus 3.4%; p = 0.02). Twenty-six (32.1%) grafts remained clear at most recent follow-up after microbial keratitis, and the proportion of clear grafts was higher after EK than PK (66.7% versus 27.8%; p = 0.03).

CONCLUSION

Rates of microbial keratitis were significantly higher after PK compared to EK, and repeat transplantation was a risk factor for microbial keratitis. To the best of our knowledge, there is no prior study in the literature evaluating microbial keratitis rates after PK and EK and comparing outcomes.

Distribution of Microbial Keratitis After Penetrating Keratoplasty According to Early and Late Postoperative Periods

Objectives:

The aim of this study was to investigate the distribution of microbial agents in the early and late postoperative periods in patients with microbial keratitis (MK) after penetrating keratoplasty (PK).

Materials and Methods:

The records of 36 patients who were clinically diagnosed as having MK after PK were retrospectively reviewed. Culture results were obtained from microbiology records and the organisms that were produced were noted. A case was deemed as viral keratitis based on the clinical appearance, negative cultures, and response to antiviral treatment. Keratitis development times were evaluated in 2 categories: early (within the first year) and late (after year 1) postoperative period. Mann-Whitney U and Kruskal-Wallis tests were used to compare numerical variables that did not show normal distribution and chi-square test was used to compare categorical variables.

Results:

The majority of MK cases were of bacterial origin (55.5%, n=20), followed by viral (41.7%, n=15) and fungal (2.8%, n=1). Of the 15 cases of early postoperative MK, 10 were bacterial, 4 were viral, and 1 was fungal; however, among cases of late postoperative MK, 10 were bacterial and 11 were viral. The majority (65%) of early and late bacterial infections were caused by gram-positive strains (most commonly staphylococci). Gram-positive bacteria caused keratitis significantly earlier than gram-negative bacteria (p=0.037). Viral and gram-negative bacterial MK was more frequent in the late postoperative period, but the difference was not statistically significant.

Conclusion:

In our study, bacterial keratitis was more common in post-keratoplasty MK than viral and fungal keratitis. Gram-positive bacteria were the most common causative agents. The increased incidence of gram-negative bacterial agents and viral keratitis in the late postoperative period can be explained by long-term topical steroid use.

Prevalence of bacteria and fungi in samples of cornea preservation fluid

INTRODUCTION

Recipients of corneal transplants are at risk of healthcare-associated infections, which, apart from other causes of surgical site infections, may also occur as a result of the transfer of infected corneal tissue. In this study we assessed the risk of bacterial and fungal infections based on the results of routine microbiological testing of cornea preservation fluid samples.

MATERIAL AND METHODS

We examined a total of 725 samples of corneal preservation fluid, obtained during a period of 3 years (2011-2013). Corneal preservation fluid samples were cultured and identified in accordance with standard microbiological methods.

RESULTS

The analysis comprised 725 samples of corneal preservation fluid, of which 32 (4.4%) samples tested positively in microbiological cultures. In total, 34 strains of bacteria and fungi were cultured. Gram-positive bacteria, Gram-negative bacteria and fungi comprised 85.3%, 8.8% and 5.9% of these strains, respectively. Analysis of the susceptibility of the cultured bacterial isolates to gentamicin was also performed, as this antibiotic is present in the composition of corneal preservation fluid. Among the cultured bacterial strains, 10 (33.3%) were resistant to gentamicin. None of the 32 patients who received a cornea stored in preservation fluid contaminated with bacteria and/or fungi demonstrated infectious complications in the surgical site within 1 year following cornea transplantation.

CONCLUSIONS

We postulate that perioperative antibiotic prophylaxis in cornea transplant recipients is important in preventing bacterial infections derived from the donor cornea. We believe that the addition of an antifungal agent to commercially available cornea preservation fluids should also be considered.

Microbial keratitis in corneal grafts: predisposing factors and outcomes

PurposeTo identify the nature of microbial keratitis in corneal grafts and the clinical outcomes at a tertiary hospital in the United Kingdom.Patients and methodsA retrospective case series of microbial keratitis in corneal grafts at the Royal Victoria Infirmary, Newcastle upon Tyne over a 17-year period (1997-2014).ResultsA total of 759 consecutive corneal grafts were identified from the Cornea Transplantation database. Of these, 59 episodes of microbial keratitis occurred in 41 eyes of 41 patients (5.4%; 19 male, 46.3%). Median patient age was 73 years (SD=19.4 years). The most common indication for corneal transplantation was bullous keratopathy (11/41, 26.8%). There were 34/59 (57.6%) episodes of culture-positive graft keratitis; Streptococcus pneumoniae and Staphylococcus aureus were each isolated in 5/34 (14.7%) culture-positive episodes. In all, 35/59 (59.3%) episodes of microbial keratitis occurred in 22 previously failed grafts and 3 de novo graft failures. Gram-negative keratitis was more likely to cause reduced BCVA after (χ²-test, P=0.02). Median graft duration was 49.5 months (SD=43.7 months). Failed grafts were significantly older (median 69 vs 27 months, P=0.009).ConclusionThis represents the longest published follow-up data on microbial keratitis and is the only of its kind in the United Kingdom. The incidence of 5.4% is comparable to that within the developed world. Graft age was significantly associated with graft failure in microbial keratitis; the ongoing risk of microbial keratitis warrants providing patients with long-term open access to hospital eye services.

Shifting trends in microbial keratitis following penetrating keratoplasty in Taiwan

To investigate the clinical and microbiological profiles from microbial keratitis following penetrating keratoplasty (PKP) in a tertiary referral center in Taiwan, the medical records of 648 consecutive patients (648 eyes) undergoing PKP between January 2003 and December 2007 were retrospectively reviewed. Patients who subsequently sustained microbial keratitis were enrolled and analyzed for potential risk factors, clinical manifestations, microbiological profiles, complications, graft survival, and final visual outcome. A total number of 42 corneal graft infections (6.5%) were recruited. Mean interval between corneal transplantation and graft infection was 12 ± 9.5 months. Potential risk factors included suture-related problems (31.0%), lid abnormalities (23.8%), persistent epithelial defect (23.8%), contact lens use (14.3%), dry eye (11.9%), and prior rejection episodes (4.8%). Lesions were discovered mostly at the donor-recipient junction ([DRJ] 45.2%). Positive cultures were identified in all of the morbid eyes, of which Pseudomonas aeruginosa was the most common pathogen (38.1%). Despite mandatory hospitalization and topical fortified antibiotics management, complications ensued such as graft failure (71.4%), hypopyon (21.4%), corneal perforation (14.3%), wound dehiscence (11.9%), and endophthalmitis (4.8%). The visual outcome was dismal that graft clarity was achieved in only 12 eyes (28.6%), and that final visual acuity deteriorated to less than 20/200 in 28 eyes (66.7%). In conclusion, microbial keratitis following PKP is a devastating event that severely impairs graft survival rate and postoperative visual outcome which usually occur within the first postoperative year. The incidence of post-PKP microbial keratitis has generally decreased in recent years whilst P. aeroginosa prevails as the leading cause of graft infection in our hospital. Close follow-up by ophthalmologists and elevated self-awareness of patients for at least one year are always encouraged to prevent late-onset infection.

A case of fungal keratitis and endophthalmitis post penetrating keratoplasty resulting from fungal contamination of the donor cornea

Purpose

Fungal infections post keratoplasty due to contamination of the donor corneal graft have become important issues that need to be addressed. Here we report a case of fungal keratitis and endophthalmitis post penetrating keratoplasty (PKP) due to fungal contamination of the donor corneal graft.

Observations

We present a 52-year-old male who underwent PKP with a donor corneal graft that was later found to be contaminated with fungus. At 4-weeks postoperative, infectious infiltrates suddenly appeared at the border between the host and donor corneal graft, and endophthalmitis concomitantly occurred. A culture of the remnant donor corneoscleral rims and the vitreous fluid obtained during vitreous surgery was found to be positive for Candida albicans. At 6-months post vitreous surgery and intensive anti-fungal medical treatment, both corneal infiltrates and vitreous opacity completely disappeared, and the patient's best-corrected visual acuity recovered to 20/40, with a transparent cornea.

Conclusions and importance

The findings of this case show that prompt intensive medical treatment and surgical intervention effectively saved the vision in a patient with fungal keratitis and endophthalmitis due to contamination of the donor corneal graft.

A comparative, retrospective, observational study of the clinical and microbiological profiles of post-penetrating keratoplasty keratitis

Infectious keratitis after penetrating keratoplasty (PK) is a devastating condition that may result in graft failure and poor visual outcome. In this study, we retrospectively reviewed the medical records of patients who underwent PK between 2009 and 2014, and recorded those who developed infectious keratitis. We compared the predisposing factors and organisms isolated to those identified in our previous study, conducted between 1989 and 1994. The incidence of post-PK infectious keratitis decreased from 11.6% (41 out of 354 cases, 1989–1994) to 6.5% (9 out of 138 cases, 2009–2014). Graft epithelial defect and suture-related problems remained the leading two risk factors of infectious keratitis after PK. Gram-positive and Gram-negative bacterial infection decreased from 58.5% and 46.3% to 11.1% and 22.2%, respectively (P = 0.023 and P = 0.271). In contrast, fungus infection increased from 9.8% to 66.7% (P = 0.001); fungi have become the major pathogen for post-PK infectious keratitis. In conclusion, while the incidence of post-PK infectious keratitis has decreased over time, the number and frequency of fungal infections have significantly increased in the recent study period. Clinicians should be aware of the shifting trend in pathogens involved in post-PK infectious keratitis.

Serologic Evaluation of Cornea Donors and Microbiologic Evaluation of Cornea Storage Media in an Eye Bank from Izmir, Turkey

OBJECTIVES

Our objective was to evaluate the serologic positivity of cornea donors and microbiologic positivity of cornea storage media at the Ege University Tissue and Cornea Bank, Izmir, Turkey.

MATERIALS AND METHODS

We retrospectively investigated the serologic blood sample and microbiological culture media analysis results of all cornea donors at Ege University Tissue and Cornea Bank between 2007 and 2015 with reference to age, sex, and cause of death of each donor.

RESULTS

Mean age of the 955 deceased donors was 43.19 ± 15.89 years (range, 2-65 y). The mean postmortem time to blood sample removal and excision of the cornea tissue was 8.4 hours (range, 4-12 h). Serologic analyses showed that 855 donors (89.5%) were seronegative. The remaining donors were seropositive for hepatitis B (54 donors; 5.7%), human immunodeficiency (27 donors; 2.8%), hepatitis C (14 donors; 1.5%), and syphilis (5 donors; 0.5%) virus infections. Microbiologic analyses of the storage media were negative, with no microorganisms shown in 855 samples (89.5%). Candida species (32 donors; 3.4%), Escherichia coli (14 donors; 1.5%), Pseudomonas aeruginosa (11 donors; 1.2%), methicillin-resistant Staphylococcus aureus (11 donors; 1.2%), Enterobacter species (11 donors; 1.2%), Klebsiella pneumoniae (7 donors; 0.7%), Acinetobacter baumannii (6 donors; 0.6%), Proteus species (5 donors; 0.5%), and Corynebacterium species (3 donors; 0.3%) were the detected microorganisms in the infected storage media.

CONCLUSIONS

False-positive serologic results among cornea donors were high. The incidence of false-positive results might be decreased by earlier blood removal from deceased donors and testing of all potential donors in intensive care units. Although rare, endophthalmitis after keratoplasty might be a devastating problem. In addition to serologic testing, microbiologic analyses of cornea storage media before transplant may be an effective way to prevent postoperative infectious complications.

Factors Affecting Treatment Outcome of Graft Infection Following Penetrating Keratoplasty

Purpose

To evaluate the factors affecting treatment outcome of graft infection following penetrating keratoplasty (PKP).

Methods

In this retrospective study, 28 patients who underwent PKP between January 2005 and January 2013 and who were diagnosed with graft infection were classified into a treatment success group or a treatment failure group. Demographic and clinical characteristics, as well as the results of the microbiologic investigation, were analyzed and compared. A subsequent binary logistic regression analysis was performed to identify the prognostic factors affecting treatment outcome.

Results

Graft infection occurred at a mean of 38.29 ± 36.16 months (range, 1 to 96 months) after PKP. Seventeen patients developed bacterial keratitis, and 11 patients developed fungal keratitis. Overall, of the 28 patients, nine (32.1%) were classified in the treatment failure group. Multivariate analysis identified pre-existing graft failure (p = 0.019), interval longer than 72 hours between donor death and PKP (p = 0.010), and fungal infection (p = 0.026) as significant risk factors for treatment failure.

Conclusions

Pre-existing graft failure, extended interval between donor death and PKP, and fungal infection were important risk factors for treatment failure of graft infection following PKP.

Clinical and microbiological profile of post-penetrating keratoplasty infectious keratitis in failed and clear grafts

PURPOSE

To comparatively evaluate the clinical and microbiological profiles and treatment outcome of cases with post-penetrating keratoplasty (PK) infectious keratitis in failed and clear grafts.

DESIGN

Retrospective, matched cohort study.

METHODS

All cases of infectious keratitis following penetrating keratoplasty admitted to the Royal Victorian Eye and Ear Hospital, Melbourne, between January 1998 and December 2008 were identified through a retrospective medical chart review. Cases without any surface sutures were selected and divided into 2 groups, microbial keratitis with pre-existing graft failure and microbial keratitis in clear graft on presentation. Demographic, clinical, and microbiological profiles of cases in both groups were analyzed and compared.

RESULTS

Patients in the failed-graft group were older (P = .004) and had an early onset of graft infection (P = .049), compared with patients in the clear-graft group. All patients in the failed-graft group were on long-term corticosteroid drops at the time of presentation (vs 76% in clear-graft group; P = .005). Moraxella sp was more frequently isolated in the failed-graft group (30.4%) compared with the clear-graft group (8%). A higher number of cases in the clear-graft group required surgical intervention in the form of corneal gluing and therapeutic corneal transplantation compared with the failed-graft group (P = .03).

CONCLUSIONS

Prolonged use of corticosteroid eye drops is a major risk factor for the occurrence of postkeratoplasty infectious keratitis in failed and clear grafts. Infections in failed grafts occur earlier as compared to clear grafts, and indolent organisms like Moraxella are prevalent in patients with failed grafts in Australia.

Incidence, occurrence rate, and characteristics of suture-related corneal infections after penetrating keratoplasty

PURPOSE

To report the incidence, occurrence rate, and characteristics of suture-related infections after penetrating keratoplasty (PK).

METHODS

Patients who underwent PK at our institution between January 1, 2002, and July 1, 2006, were cross-referenced with patients diagnosed with corneal infections between January 1, 2002, and July 1, 2007. All patient charts were reviewed retrospectively for occurrence of suture-related infections, duration of follow-up, and clinical characteristics.

RESULTS

Of the 487 PKs performed in 412 patients, 22 eyes of 22 patients developed postoperative corneal infections. Of these, 5 eyes were identified as having suture-related graft infections, yielding an occurrence rate of 1.0%. The average follow-up was 3.46 years per PK, yielding an incidence of 2.96 infections per 1000 PK-years. The mean interval from surgery to infection was 8 months (range: 3-23 months). All culprit sutures were in the interpalpebral zone. No patients were using topical antibiotics at the time of infection, and all patients were using topical corticosteroid drops. Cultured organisms included Staphylococcus aureus (3 cases), coagulase-negative Staphylcoccus (1 case), and S. viridans (1 case). In 2 patients with isolated corneal involvement, topical moxifloxacin was initiated, and the patients responded favorably. In 3 patients with corneal infection and an associated hypopyon or endophthalmitis, vitreous biopsy, intravitreal injections of antibiotics, and fortified topical antibiotics were used. One patient required a repeat PK as a result of the infection. Two eyes eventually became phthisical.

CONCLUSIONS

The rate of suture-related infections after PK may be lower than previously reported. In our patients, suture-related infections all occurred within the first 2 years after surgery, and some of them resulted in significant morbidity, underscoring the importance of patient identification of symptoms and early clinical recognition.

Ocular mycosis at a referral center in Saudi Arabia: A 20-year study

PURPOSE

To review the clinical experience of fungal keratitis cases at King Khaled Eye Specialist Hospital (KKESH) in Riyadh, Saudi Arabia.

METHODS

Retrospective observational review and analysis of 124 patient charts with confirmed diagnosis of fungal keratitis between 1984 and 2004.

RESULTS

One hundred and twenty four eyes of 124 patients had proven fungal infection; 101 eyes had fungal keratitis and 23 eyes had fungal endophthalmitis complicating keratitis. Estimated proportion of fungal keratitis and endophthalmitis was 10.3%. Mean age was 55 years with male predominance (79.0%). Commonly associated factors were previous intraocular surgery (38.7%) and trauma (20.9%). Major risk factor for progressing to endophthalmitis was previous intraocular surgery (65.2%), p < 0.001. Initial laboratory results were fungal positive only in 30.6% (p < 0.001). Commonest organisms isolated were Aspergillus spp. (29.8%) followed by Trichophyton sp. (16.1%), then Candida and Fusarium sp. Comparison of both phases of the study showed improvement in the rate of successfully treated cases from 34.6% to 58.3%, and a decline in cases progressing to endophthalmitis from 25.0% to 13.9%. Therapeutic penetrating keratoplasty increased from 26.9% to 73.6% (p < 0.001). Thirteen eyes required enucleation or evisceration.

CONCLUSIONS

In contrast to other studies on fungal keratitis, Aspergillusspp. and Trichophyton sp. were the most commonly isolated fungal pathogens; the former carries the worst prognosis. Risk factors included previous intraocular surgery and trauma. Poor outcome was associated with Aspergillus spp., delayed presentation, previous intraocular surgery and late surgical intervention. This study recommends early surgical intervention to improve the outcome.

Evaluation of molecular diagnosis in fungal keratitis. Ten years of experience

Purpose

The aims of this study were to assess the utility of polymerase chain reaction (PCR) in diagnosing fungal keratitis in the last decade in our center and to review the molecular diagnosis of mycotic keratitis.

Methods

A retrospective nonrandomized investigation was undertaken at Vissum Corporación Instituto Oftalmologico de Alicante to evaluate 27 corneal samples of 20 patients with proven fungal keratitis from January 2000 to December 2009. Corneal samples (21 corneal scrapings, 5 biopsies, and 1 cornea) were evaluated by Gram stain or calcofluor stain, culture, and PCR. The detection and molecular identification were carried out by DNA amplification and sequencing of the internal transcribed spacer and 5.8S rRNA region from the corneal samples.

Results

PCR detected all the samples that were positive by conventional methods. Four samples were positive by PCR and showed negative results by culture and stain. Combination of microscopy and culture gave positive results in 21 of the 27 samples of patients with mycotic keratitis. Stains showed a 66.7% of positive results, culture showed 59.3%, and PCR showed 92.6%. The time taken for PCR assay was 4 to 8 h whereas positive fungal cultures took 1 to 35 days. Identification at species level by molecular methods was possible in all cases except one. Identification at species level by conventional methods only was possible in eight cases.

Conclusions

PCR not only proved to be an effective rapid method for the diagnosis of fungal keratitis but was also more sensitive than stain and culture methods. Fungal PCR must be added as the screening diagnosis test when an early mycotic keratitis is suspected. Molecular identification is the gold standard technique for the identification of corneal fungal pathogens.

Epidemiologic aspects and clinical outcome of fungal keratitis in southeastern Brazil

PURPOSE

Fungal keratitis (FK) is a sight-threatening disease, more prevalent in developing regions. The present retrospective study was conducted in order to evaluate the epidemiologic and clinical aspects and the progression of FK in patients treated at two ophthalmologic reference centers in Southeast Brazil.

METHODS

The charts of patients with infectious keratitis treated between 2000 and 2004 were reviewed. For the 66 cases of FK confirmed by microbiological analysis, data related to patient, disease, and therapeutic approaches were obtained.

RESULTS

Mean patient age was 40.7+/-16 years. Fifty-three were men and 13 were women. Ocular trauma occurred in 40% of cases (27). Previous medications taken by the patients were quinolone in 72.5% and antimycotics in 30%. Visual acuity (VA) at presentation was >0.3 in 16% and <0.1 in 74.5%. Penetrant keratoplasty was performed in 38% and evisceration in 15%. The causing agents were Fusarium sp in 67%, Aspergillus sp in 10.5%, and Candida sp in 10%. Medication alone resolved 39% of cases within a mean period of 24.5+/-12 days. Final VA was >0.3 in 28%, and <0.1 in 63%.

CONCLUSIONS

Fungal keratitis presented as a disease with severe complications, predominantly among young males, and was mostly caused by filamentous fungi. The present information permits the establishment of preventive strategies. Reducing the time between onset and treatment and using more accessible specific medication would reverse the negative prognosis.

Fungal keratitis in the United Kingdom 2003-2005

PURPOSE

To describe the incidence and current management of fungal keratitis in the United Kingdom.

METHODS

Cases were identified prospectively through the British Ophthalmologic Surveillance Unit (BOSU) from December 2003 to November 2005. Questionnaire data were requested at diagnosis and at 6 months follow-up. Inclusion criteria were a positive culture or microsopic proof from a scraping or biopsy, and a normal residence in the United Kingdom.

RESULTS

Data were available on 39 confirmed cases at diagnosis and 34 cases at follow-up. The minimum average annualised incidence was 0.32 (95% CI, 0.24-0.44) cases per million individuals. In 22 cases (56%), only Candida was isolated and 14 of these (63%) had prior ocular surface disease treated with topical steroid. A filamentary fungus infection was more common in male patients (P=0.02), often following trauma, and the differences in risk factors between types of fungal infection was statistically significant (P<0.001). One case had a mixed yeast and filamentary fungus infection. The most frequent initial topical therapies were amphotericin B (38%) or econazole (28%). In addition, oral fluconazole was used in 11 (31%) patients and oral itraconazole in six (15%). At follow-up, the vision in 15 eyes (44%) was <6/60 including three eyes eviscerated.

CONCLUSIONS

This study provides data on the minimum incidence of fungal keratitis in the United Kingdom. It provides evidence of frequent delay in diagnosis after presentation to eye departments, inconsistent management, and poor outcome. Issues that can now be addressed.

Fungal keratitis in London: microbiological and clinical evaluation

PURPOSE

To review cases of culture-positive fungal keratitis seen at Moorfields Eye Hospital over a 13-year period to January 2007.

METHODS

Isolates were identified retrospectively from laboratory reports. The clinical records were reviewed. The fungal type, risk factors for infection, in vitro sensitivity, and clinical outcome were recorded.

RESULTS

There were 66 isolates from 65 patients (men, 53.8%). Forty (60.6%) of the isolates were subspecies of Candida. The average interval from the onset of keratitis to confirmation of fungal infection was 3.4 weeks (median, 1.0 week; range, 0-16 weeks). Prior ocular surface disease (OSD) or a penetrating keratoplasty (PK) was present in 38 (97.4%) patients with Candida infection, and 29 (74.4%) patients with Candida infection were using topical steroid at the time of diagnosis. The principal risk factors for filamentary fungal infection were trauma (8 cases, 30.8%) or cosmetic contact lens wear (8 cases, 30.8%), with OSD or a prior PK each present in 5 (19.2%) cases. The difference in the proportions of risk factors between the 2 fungal groups was statistically significant (P < 0.000). The visual outcome was similar between groups, and at final review, 27 (41.5%) eyes had a visual acuity of < or = 1/60 and 3 (4.6%) eyes were eviscerated. In vitro sensitivity testing showed full or part sensitivity in 100% of 55 isolates tested against econazole, 87.9% of 58 isolates tested against amphotericin, 75% of 40 isolates tested against itraconazole, and 100% of 20 isolates tested against voriconazole.

CONCLUSIONS

Candida was the principal isolate, usually from eyes with OSD or a prior PK treated with topical steroids.

Microbial keratitis following corneal transplantation

PURPOSE

To determine the predisposing risk factors and analyse the clinical and microbiological profiles of microbial keratitis following corneal transplantation.

METHODS

A retrospective analysis was done of hospital records of all patients who presented with microbial keratitis in the corneal graft between July 2000 and June 2005 at the Corneal Unit of Royal Victorian Eye and Ear Hospital, Melbourne, Australia.

RESULTS

Eighty-one episodes of infection were identified in 62 patients over a 5-year period. Thirteen patients had multiple episodes of infection. The mean age of the patients was 70 +/- 16 years (range: 22-92 years). The median time interval between the graft and infection was 17 months (range: 6 days to 385 months). Twenty-two (35%) episodes of primary infection were related to sutures. The associated predisposing risk factors were failed graft (40%), dry eye (18%), Herpes simplex keratitis (8%), and ocular surface disease (8%). Forty-seven (76%) cases were culture positive for bacteria. Ten cases were positive for Herpes simplex virus (HSV) during presentation.

CONCLUSION

Failed graft is a long-term risk factor for graft infection in addition to ocular surface disease and H. simplex keratitis. All the predisposing risk factors increase the risk of recurrent graft infection.

Infectious keratitis following keratoplasty

Infectious keratitis following corneal transplantation is one of the leading causes of failure of a corneal graft. The incidence of graft infection is variable, with developing countries having a higher incidence. The majority of the graft infections occur within 1 year of the corneal transplantation. Suture-related problems and persistent epithelial defect are the most common risk factors predisposing to graft infection. Pneumococcus species and Staphylococcus aureus have been found to be the commonest microorganisms in the developed world, whereas Staphylococcus epidermidis is the most often detected microorganism in corneal graft infection in the developing world. The early identification of predisposing risk factors in patients and their appropriate management at the earliest may prevent the occurrence of graft infection and might improve graft survival. Visual prognosis in eyes with post-keratoplasty graft infection is poor even after optimal therapy and there is a high rate of graft decompensation.

Microbial keratitis following corneal transplantation

PURPOSE

To study clinical and microbiologic characteristics of corneal infections following penetrating keratoplasty (PK).

DESIGN

Retrospective case series.

METHODS

Medical records of patients who presented to Duke University Eye Center from January 1, 1999 to July 1, 2005 with microbial keratitis after PK were reviewed.

RESULTS

Forty-four corneal graft infections were reviewed. Mean interval between PK and infection was 26.3 months. Associated conditions included broken or loose sutures (10, 22.7%) and topical corticosteroids (34, 77.3%). Staphylococcal (12, 20.7%) and Pseudomonal (7, 12.1%) species were common pathogens, and fungal species accounted for eight (18.2%) infections. Twelve patients (27.3%) had polymicrobial infections. Thirteen patients (29.5%) underwent repeat PK. Mean postinfection visual acuity at last follow-up was 20/400.

CONCLUSIONS

Microbial infections within corneal grafts can occur anytime in the postoperative course and are associated with broken sutures and the use of topical corticosteroids. The diversity of pathogenic organisms, antibiotic resistance, and the potential for poor outcomes supports aggressive management of these infections.

Spectrum of Fungal Keratitis in North China

PURPOSE

To report the epidemiological features, laboratory findings, and treatment outcomes in patients with fungal keratitis in north China.

DESIGN

Retrospective hospital-based study.

PARTICIPANTS

A total of 654 patients diagnosed with fungal keratitis at the Shandong Eye Institute from January 1999 to December 2004.

METHODS

The medical records of 654 inpatients (654 eyes) with fungal keratitis were reviewed retrospectively for demographic features, risk factors, seasonal variation, clinical characteristics, laboratory findings, and treatment strategy.

MAIN OUTCOME MEASURES

Patient history, ocular examination findings by slit-lamp biomicroscopy, laboratory findings from direct smear examination and fungal culture, and treatment protocol.

RESULTS

Fungal keratitis constituted 61.9% of cases of severe infective keratitis among the inpatients at the Shandong Eye Institute during the 6 years. Males (60.6%) were more likely to be affected by fungal keratitis than females (39.4%). Almost one third of the patients (203) were middle aged (41-50 years old). Corneal trauma (51.4%), especially injury from plants (25.7% in all patients), was the most commonly associated risk factor. The incidence of fungal keratitis was higher in harvest seasons, including summer and autumn. An increasing tendency of incidence was noted in more recent years. Direct microscopic examination of the corneal scraping samples stained with potassium hydroxide showed positivity in 88.7% of the eyes. The fungal isolates were of Fusarium species in 437 eyes (73.3%) and Aspergillus species in 72 eyes (12.1%). Surgical interventions were performed in 604 eyes (92.4%), including therapeutic penetrating keratoplasty in 399 eyes (66.0%) and therapeutic lamellar keratoplasty (LK) in 177 eyes (29.3%). Globe integrity was preserved in 626 eyes (95.7%).

CONCLUSIONS

With Fusarium species being the most commonly isolated pathogens, fungal keratitis is the leading cause of severe infective corneal ulcers in north China. Direct microscopic examination with potassium hydroxide wet mounts proves to be a rapid, simple, inexpensive diagnostic means. Corneal transplantation continues to be the most effective approach for the treatment of severe fungal keratitis. Early surgery, especially LK, can be considered if aggressive topical therapy does not achieve early disease control.

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.

Successful Topical Application of a New Antifungal Agent, Micafungin, in the Treatment of Refractory Fungal Corneal Ulcers

PURPOSE

To report the efficacy of topical application of a new antifungal agent, micafungin (MCFG), in the treatment of yeast-related corneal ulcers.

DESIGN

Noncomparative interventional case reports.

PARTICIPANTS

Three patients with yeast-related corneal ulcer after keratoplasty recalcitrant to conventional antifungal treatment for 4 weeks were recruited in this study.

METHODS

Topical 0.1% antifungal MCFG eye drops were applied in 3 patients with yeast-related corneal ulcer every hour while awake until epithelialization. After epithelialization, the frequency of eye drops was reduced to 5 times a day. MCFG eye drops were discontinued 1 month after the disappearance of stromal infiltration in each case. The patients underwent best corrected visual acuity (BCVA) measurements, slit-lamp examination, fluorescein-dye staining, and anterior segment photography. Corneal scrapings and cultures of surgical materials were also performed.

MAIN OUTCOME MEASURES

Changes in ulcer size, stromal infiltration, fluorescein dye staining, and BCVA were looked for.

RESULTS

All corneal ulcers epithelialized within 14 days after commencement of application of 0.1% MCFG eye drops. Yeasts were detected from corneal smears in all eyes. Two cases revealed positive culture isolates for Candida albicans and Candida parapsilosis. No recurrence of fungal keratitis was observed in any of the cases throughout the follow-up periods.

CONCLUSION

Topical 0.1% MCFG eye drops seem to be an effective and a promising option in the treatment of refractory yeast-related corneal ulcers.

The Incidence of Fungal Keratitis and Endophthalmitis Following Penetrating Keratoplasty

PURPOSE

To determine the incidence of postkeratoplasty fungal endophthalmitis and keratitis at the New York Eye and Ear Infirmary. To determine whether there is a relationship between culture-positive corneoscleral donor material and postoperative infection.

METHODS

The microbiologic records of corneoscleral donor rims submitted for culture following penetrating keratoplasty at the New York Eye and Ear Infirmary between January 1998 and January 2003 were reviewed. The incidence of rim cultures positive for fungi was tabulated. Clinical outcome measures were recorded for each patient receiving corneal donor tissue.

RESULTS

Of 2466 donor corneoscleral rims cultured during the study period, 344 were positive for microbial growth (13%). Of those rims with positive cultures, 28 (8.6%) were positive for fungus. All fungi cultured were Candida species. Four of the 28 recipient eyes (14%) who received contaminated donor material went on to develop postkeratoplasty fungal infections. There were no cases of fungal infection in any postkeratoplasty patients in the absence of contaminated donor rims during the study period. Overall, there was a 0.16% incidence of fungal infection (4/2466) following penetrating keratoplasty. There were 18 positive donor rims identified in the first 4 years of the study, but there were 10 cases in the last 10 months of the study.

CONCLUSIONS

The overall incidence of fungal infection following penetrating keratoplasty is low, but all cases in our study were associated with positive rim cultures. Whether prophylactic antifungal therapy would be of any benefit in the presence of a positive corneoscleral rim culture has not yet been determined.

Microbial Keratitis Following Lamellar Keratoplasty

OBJECTIVE

To determine the predisposing factors, etiologic agents, and clinical and visual outcomes in infectious keratitis following lamellar keratoplasty (LK).

METHODS

One hundred thirty-five eyes (135 patients) that had undergone LK were retrospectively analyzed for the occurrence of infectious keratitis following LK. The parameters evaluated were predisposing factors, seasonal variation, indications and type of LK, time interval between LK and infection, site and depth of infection, etiologic organisms, type of treatment, outcome in terms of graft status, secondary surgery, visual acuity, and the donor tissue profile.

RESULTS

The incidence of infectious keratitis following LK was 11.11%. The most significant predisposing factor was persistent epithelial defect (3 eyes) and suture abscesses (3 eyes). Most cases occurred between May and August (9/15). Twelve cases developed infection within 2 weeks of surgery (80%). Seven cases (7/15) occurred with onlay grafts, 6 with inlay grafts, and 2 with large-diameter LK. Cultures of corneal scrapings were positive in 11 eyes (73.3%), and the most common isolated organism was coagulase-negative Staphylococcus (CNS). Only 2 eyes responded to medical therapy, and graft sloughing occurred in 9 cases. Six eyes underwent penetrating keratoplasty to either salvage the integrity of globe or for visual rehabilitation of cases where infection resulted in corneal opacity.

CONCLUSIONS

Infections after LK may not be amenable to antimicrobial therapy and may necessitate the removal of the graft or a therapeutic penetrating keratoplasty.

Candida parapsilosis keratitis

PURPOSE

To present clinical, microbiologic, and histopathologic features of keratitis due to Candida parapsilosis.

METHODS

Clinicomicrobiologic evaluation of four patients (four eyes) with culture-proven C. parapsilosis keratitis. The patients were evaluated for symptoms, visual acuity, clinical observations, microbiologic examination of corneal scrapings, and pathologic examination of corneal buttons.

RESULTS

Three cases were observed after penetrating keratoplasty, and one case occurred after inhalation of corticosteroids. Clinical presentation of C. parapsilosis keratitis showed a great diversity. There was one case of crystalline keratopathy and three cases of suppurative corneal infiltrate. Histopathology of corneal buttons showed interlamellar accumulations of yeast. Medical treatment included topical amphotericin B and systemic triazoles. Penetrating keratoplasty was required in three patients.

CONCLUSION

Risk factors for C. parapsilosis keratitis may include corticosteroid use and prior corneal transplantation. The prognosis of C. parapsilosis keratitis with antifungal and surgical therapy may vary from good visual outcome to intraocular extension with phthisis bulbi.

Epicorneal aspergilloma after penetrating keratoplasty

PURPOSE

To report an epicorneal aspergilloma in a postkeratoplasty patient with a bandage soft contact lens.

METHODS

Case report of a 77-year-old postkeratoplasty patient who presented with an epicorneal mass under a bandage soft contact lens placed for a nonhealing epithelial defect. On removal of the contact lens, a 4 x 4-mm placoid mass fell free from the corneal surface and was sent for culture and histopathology.

RESULTS

Gram stain demonstrated septated branching hyphae, and cultures confirmed the diagnosis of Histopathologic sections of the epicorneal mass revealed a full-thickness aspergilloma.

CONCLUSION

Contact lens removal and aggressive antimycotic treatment resulted in epithelial healing and resolution of the keratomycosis. The patient remained stable for 6 months followed by a successful repeat penetrating keratoplasty.