Microbial keratitis in children

Infectious keratitis in pediatric population aged less than two years: a tertiary eye institute experience

BACKGROUND

Infectious keratitis is a serious ocular condition, which can lead to corneal scarring, vision loss, and even blindness. Pediatric infectious keratitis accounts for about 13% of all cases, although there is a lack of comprehensive data regarding keratitis in less than two years of age population group. This study was aimed to determine predisposing factors, clinical characteristics, microbial profile, and management of infectious keratitis in a population of children aged less than two years.

MATERIALS AND METHODS

A retrospective study was carried out in a tertiary eye institute over a period of 18 years from July 2005 to December 2022. Collected data was analyzed for demographics, predisposing factors, clinical features, and treatment methods.

RESULTS

Fifty-seven cases of keratitis were identified. Age of the patients ranged from 1 to 24 months (Median: 6, interquartile range: 2-10). Thirty cases were male (52.6%). Predisposing factors were identified in 39 cases (68.4%): consisting of prior ocular trauma (n = 15), previous intraocular surgery (n = 11), ocular surface disease (n = 10), nasolacrimal duct obstruction (n = 4), prematurity (n = 3), developmental delay (n = 2), TORCH infection (n = 1), and contact lens (n = 1). Corneal thinning was observed in 29 eyes (50.9%), which progressed to perforation in 13 eyes (22.8%). Three patients developed endophthalmitis (95% CI, 1.5-13.4%). Most eyes had negative smear (60.4%) and culture (59.6%) results. Pseudomonas aeruginosa was the most common microorganism (11 of 21). Candida albicans was isolated in one case. In vitro susceptibility results showed good coverage of the combined ceftazidime and vancomycin regimen (100%). Surgical procedures were carried out in 35 eyes (61.4%) and 15 eyes required tectonic procedures (26.3%).

CONCLUSION

Despite good coverage of medical treatment over cultured isolates, surgical tectonic intervention was required in nearly a quarter of cases to resolve the corneal infection. This finding indicates the necessity of prompt patient referring, corneal sampling and initiation of the treatment.

Ocular microbial dysbiosis and its linkage with infectious keratitis patients in Northwest China: A cross-sectional study

OBJECTIVES

To evaluate the alteration of ocular surface microbiome of patients with infectious keratitis in northwest of China.

METHODS

The corneal scrapings, eyelid margin and conjunctiva samples were collected from 57 participants, who were divided into bacterial keratitis, fungal keratitis, viral keratitis and control group. The V3-V4 region of bacterial 16S rDNA in each sample was amplified and sequenced on the Illumina HiSeq 2500 sequencing platform, and the differences among different groups were compared bioinformatically.

RESULTS

Significant alterations of the microbiome were observed in alpha-diversity and beta-diversity analysis between the keratitis groups and the control group (p < 0.05). There was no significant differences between eyelid margin and conjunctiva samples in Alpha-Diversity analysis, but a significant difference between eyelid margin and corneal scraping samples in the keratitis group (p < 0.05, independent t-test). The abundances of Bacillus, Megamonas, Acinetobacter, and Rhodococcu were significantly elevated, while the abundance of Staphylococcus was decreased in the keratitis group compared to the control group.

CONCLUSIONS

The abundance of the ocular microbiome in patients with bacterial keratitis, fungal keratitis, or viral keratitis was significantly higher than those in the control group. Keratitis patients may have ecological disorder on ocular surface microbiome compared with controls. We believe that the conjunctiva and eyelid margin microbiome combined analysis can more comprehensively reflect the composition and abundance of ocular surface microbiome.

Incidence of Corneal Adverse Events in Children Wearing Soft Contact Lenses

OBJECTIVES

There is increasing interest in fitting children with soft contact lenses, in part due to the increase in prescribing of designs to slow the progression of myopia. This literature review summarizes large prospective and retrospective studies that include data on the incidence of microbial keratitis and corneal infiltrative events (CIEs) in children wearing soft contact lenses.

METHODS

Peer-reviewed prospective and retrospective studies that report contact lens-related complications in children with at least one year of wear and at least 100 patient years of wear were identified.

RESULTS

Seven prospective studies published between 2004 and 2022 were identified representing 3,752 patient years of wear in 1,756 children, nearly all of whom were fitted at age 12 years or younger. Collectively, they report one case of microbial keratitis and 53 CIEs, of which 16 were classified as symptomatic. The overall incidence of microbial keratitis was 2.7 per 10,000 patient years (95% CI: 0.5-15), and the incidence of symptomatic CIEs was 42 per 10,000 patient years (95% CI: 26-69). Two retrospective studies were identified representing 2,545 patient years of wear in 1,025 children, fitted at age 12 years or younger. One study reports two cases of microbial keratitis giving an incidence of 9.4 per 10,000 patient years (95% CI: 0.5-15).

CONCLUSIONS

Accurate classification of CIEs is challenging, particularly in retrospective studies. The incidence of microbial keratitis in children wearing soft lenses is no higher than in adults, and the incidence of CIEs seems to be markedly lower.

Borrelia Ocular Infection: A Case Report and a Systematic Review of Published Cases

INTRODUCTION

Lyme borreliosis can cause many diverse manifestations, also ocular disease where the diagnosis of ocular borreliosis is challenging. The primary aim was to report on the evidence of Borrelia spirochetes in the ocular tissue in presumed ocular borreliosis.

METHODS

A systematic review of pathological eye conditions was performed where Borrelia has been suspected in relevant ocular tissue, together with a case report of diagnosed uveitis with polymerase chain reaction (PCR)-confirmed Borrelia afzelii in the vitreous. The evidence for clinical and laboratory diagnosis was evaluated systematically. As a secondary aim, the treatment of ocular Borrelia infection was also evaluated for confirmed cases.

RESULTS

Thirteen includable studies were found, and after the removal of case duplicates, eleven unique cases were extracted. Apart from the present case report, 4 other cases reported strong evidence for the detection of B. spirochetes in ocular tissue. Four cases presented reasonable evidence for assumed detected Borrelia, while three additional cases showed only weak diagnostic credibility that Borrelia was detected.

CONCLUSION

This systematic review, including all reported cases and our case report, supports evidence of ocular infection of Borrelia species. Furthermore, in case of suspicion of infection and seronegativity, it is justified to look for Borrelia in eye tissue samples. In addition, microscopy without using PCR is not sufficient to confirm the diagnosis of borreliosis on ocular tissue. In the articles studied, there was no unambiguous recommendation of treatment.

A ten-year report of microbial keratitis in pediatric population under five years in a tertiary eye center

Purpose

To report characteristics of microbial keratitis in pediatric patients under five years.

Methods

Patients with infectious keratitis under the age of 5 years were included in this retrospective cross-sectional study for ten years. All patients were admitted and corneal scraping was performed in 81 children. Fortified empiric antibiotic eye drops including cefazolin (50 mg/cc) and amikacin (20 mg/cc) were started and the antibiotic regimen was continued or changed according to culture results. In the case of fungal keratitis, topical voriconazole (10 mg/cc) or natamycin (50 mg/cc) and topical chloramphenicol (5 mg/cc) were started. A tectonic procedure was done when corneal thinning or perforation was present.

Results

Ninety-Three Patients between 1 to 60 months with a mean age of 33 ± 18 months old with corneal ulcer were included in the study. The most common risk factor was trauma (40.9%) followed by contact lens use (8.6%). Cultures were negative for microbial growth in 28 (30.1%) patients. The most common pathogens were S. epidermidis (10.8%) and P. aeruginosa (10.8%). Fluoroquinolone antibiotics (ciprofloxacin; 93.8% sensitivity) were the most potent antibiotic against bacterial pathogens. Forty-one patients underwent tectonic procedures, which the most common ones were cyanoacrylate glue 18.3% followed by keratoplasty 16.1%.

Conclusion

This study emphasizes the role of trauma as the primary cause and S. epidermidis as the most frequent microorganism in pediatric keratitis; according to antibiogram results and poor cooperation of patients under five years, monotherapy with fluoroquinolones could be a good regimen in small non-central lesions without thinning.

Pediatric Microbial Keratitis: Experience From Tertiary Referral Centers in New South Wales, Australia

AIMS

The purpose of this study was to report the epidemiology, etiology, microbiologic profile and management of pediatric microbial keratitis in a quaternary and 3 tertiary ophthalmic referral centers across Sydney, New South Wales, Australia.

METHODS

This is a retrospective cohort study of patients ≤ 18 years of age with a clinical diagnosis of microbial keratitis presenting between 1 January 2010 and 31 December 2016 identified from hospital coding and pathology databases. Data were extracted from the medical records. Epidemiology, predisposing factors, referral patterns, microbial profile and treatment outcomes were analyzed.

RESULTS

Eighty eyes from 80 pediatric patients with microbial keratitis were included in the study (10% had bilateral disease). The mean age was 11 ± 5.3 years (range 0-18 years), and 44 were male (55%). Thirty-six percent of patients had ocular and 13.5% systemic comorbidities. The most common risk factor overall was contact lens wear in 26%, trauma (24%), and external lid and eye disease (20%). Overall, 74 organisms were identified, and of those, the most common isolates were Gram-positive organism. Antimicrobial resistance to common antibiotics was low across all isolates. Visual acuity following treatment was worse than 6/60 for 7 patients (11.3%%), 6/15-6/60 for 15 patients (24.2%) and better than 6/12 for 40 patients (64.5%). Preexisting corneal disease and delay of presentation were associated with worse visual prognosis. Serious complications were noted in 16 (21.3%) of patients.

CONCLUSIONS

Contact lens wear, trauma and existing ocular disease remain the most significant risk factors in the pediatric population. Preexisting corneal disease and delay in presentation were associated with poor visual acuity. The majority of patients have a good visual outcome although serious complications are not uncommon and may cause lifelong visual disability.

A global perspective of pediatric non-viral keratitis: literature review

PURPOSE

This focused review aims to explore pediatric non-viral keratitis and to compare associated risk factors, etiologies, antibiotic susceptibilities, empiric treatments and outcomes.

METHODS

The authors performed a literature research for articles, published on PubMed, Google Scholar, Scopus and Embase online library, relevant to pediatric keratitis etiology, risk factors, antibiotic susceptibilities, treatment and outcomes. From the bibliography of selected articles, additional relevant articles were also considered. Of 34 articles identified, 21 were suitable for the purpose of this review.

RESULTS

Several risk factors are noted in the field of pediatric keratitis. Trauma is the most common in developing countries, while contact lenses wear is seen in developed economies. Previous ocular conditions and systemic diseases also contribute. Associated malnourishment and vitamin A deficit are fraught with a catastrophic prognosis. Among causative organisms, bacteria are more common than fungi and protozoa. Gram-positive organisms are predominant where contact lenses use is infrequent. Pseudomonas aeruginosa is often the leading pathogen in developed countries and is strongly associated with contact lens wear or malnourishment. Fungi are common in the tropics and associated with trauma. Levofloxacin seems the more effective empirical treatment when bacteria are suspected, but there is no agreement on a standard of care.

CONCLUSION

There are differences in etiologic patterns between developing and developed countries and different regions globally. Risk factors follow the same trend; however, there is no standard regimen being followed for empirical treatment of pediatric infectious keratitis. Associated malnourishment and vitamin A deficiency result in poorer outcomes.

Demographic details, risk factors, microbiological profile, and clinical outcomes of pediatric infectious keratitis cases in North India

Purpose:

To study the demographic details, risk factors, microbiological profile, and clinical outcomes of pediatric infectious keratitis cases in North India.

Methods:

This retrospective case series included review of medical records of pediatric patients (0–16 years) diagnosed with infectious keratitis in a tertiary care center of North India during December 2011 to January 2017 was done. Demographic details, predisposing factors, microbiological investigations, and clinical outcomes were analyzed.

Results:

In this time period, 104 eyes of 104 children had a diagnosis of infectious keratitis. Culture was obtained for all 104 eyes and was positive in eighty eight eyes (84.2%). The most common causative factor was trauma, seen in 77 eyes (74%). Bacteria was the most common agent isolated in culture (54.2%) followed by fungi (40.8%) and acanthamoeba (2.1%). Successful healing of the keratitis with appropriate medical treatment occurred in 84 (80.7%) eyes, while 13 (12.5%) eyes required therapeutic keratoplasty. Of the 80 eyes with documentation of both preliminary and final visual acuity, improvement of two lines was seen in 35 eyes (43.7%), stayed the same in and worsened in 17 eyes (21%). Mean time to resolution of infection on medical treatment for bacteria was 23.65 ± 4.78 days, fungi 32 ± 5.19 days, and acanthamoeba 53.67 ± 4.78 days.

Conclusion:

Gram positive organism is the most common etiological agent of keratitis in children in our study population which is in contrast to pediatric infective keratitis study conducted by Aruljyothi et al. in South India (2011--2013). Though less in number than bacterial keratitis, fungus also remains an important causative agent. Along with early diagnosis and immediate medical intervention, it is important to identify regional profile of organisms and risk factors for good visual and anatomical outcome.

The Spectrum of Microbial Keratitis: An Updated Review

Background:

In microbial keratitis, infection of the cornea can threaten vision through permanent corneal scarring and even perforation resulting in the loss of the eye. A literature review was conducted by Karsten, Watson and Foster (2012) to determine the spectrum of microbial keratitis. Since this publication, there have been over 2600 articles published investigating the causative pathogens of microbial keratitis.

Objective:

To determine the current spectrum of possible pathogens implicated in microbial keratitis relative to the 2012 study.

Methods:

An exhaustive literature review was conducted of all the peer-reviewed articles reporting on microbial pathogens implicated in keratitis. Databases including MEDLINE, EMBASE, Scopus and Web of Science were searched utilising their entire year limits (1950-2019).

Results:

Six-hundred and eighty-eight species representing 271 genera from 145 families were implicated in microbial keratitis. Fungal pathogens, though less frequent than bacteria, demonstrated the greatest diversity with 393 species from 169 genera that were found to cause microbial keratitis. There were 254 species of bacteria from 82 genera, 27 species of amoeba from 11 genera, and 14 species of virus from 9 genera, which were also identified as pathogens of microbial keratitis.

Conclusion:

The spectrum of pathogens implicated in microbial keratitis is extremely diverse. Bacteria were most commonly encountered and in comparison, to the review published in 2012, further 456 pathogens have been identified as causative pathogens of microbial keratitis. Therefore, the current review provides an important update on the potential spectrum of microbes, to assist clinicians in the diagnosis and treatment of microbial keratitis.

The persistent dilemma of microbial keratitis: Global burden, diagnosis, and antimicrobial resistance

Microbial keratitis is a potentially blinding condition that must be treated emergently to preserve vision. Although long recognized as a significant cause of corneal blindness, our understanding of its true global scale, associated burden of disease, and etiological patterns remains somewhat limited. Current epidemiological data suggest that microbial keratitis may be epidemic in parts of the world-particularly within South, South-East, and East Asia-and may exceed 2 million cases per year worldwide. Etiological patterns vary between economically developed and developing countries, with bacterial predominance in the former and fungal predominance in the latter. The key to effective management lies in timely diagnosis; however, the current gold standard of stain and culture remains time consuming and often yields no clinically useful results. For this reason, there are attempts to develop highly sensitive and accurate molecular diagnostic tools to provide rapid diagnosis, inform treatment decision making, and minimize the threat of antimicrobial resistance. We provide an overview of these key areas and of avenues for further research toward the goal of more effectively addressing the problem of microbial keratitis on both an individual and public health level.

Geographic Disparities in the Etiology of Bacterial and Fungal Keratitis in the United States of America

Infectious keratitis is a serious cause of vision loss. Proper treatment of infectious keratitis requires antimicrobials that target the organism responsible for a patient's ulcer. The frequency of infection by a given organism varies by location. We examined the literature to determine geographic disparities in the etiology of bacterial and fungal keratitis in the United States of America. Bacterial keratitis makes up a greater proportion of cases in northern locations, and fungal keratitis increases in prevalence in southern locations. Gram-negative organisms make up a greater proportion of bacterial keratitis in southern locations when compared to northern locations.

Pediatric microbial keratitis in Taiwan: clinical and microbiological profiles, 1998-2002 versus 2008-2012

PURPOSE

To identify the change in clinical and microbiological profiles of pediatric microbial keratitis in Taiwan between 1998-2002 and 2008-2012.

DESIGN

Retrospective, observational study.

METHOD

setting: Chang Gung Memorial Hospital, a referral center in Taiwan. patient population: We retrospectively reviewed the medical records of 68 eyes of 67 children aged 16 years or younger who were diagnosed with microbial keratitis and treated at our hospital between July 2008 and December 2012. main outcomes and measures: Predisposing factors, isolated organisms, antibiotic susceptibility, and clinical outcomes. The findings were compared with the results of our previous study conducted between July 1998 and December 2002.

RESULTS

As in 1998-2002, the leading risk factor for microbial keratitis during 2008-2012 was contact lens use, and the infection rate significantly increased from 40.7% to 52.9% (P = .024), which was mainly attributable to the recent increase in the rate of orthokeratology-related keratitis from 9.9% to 19.1% (P = .011). Pseudomonas aeruginosa remained the most commonly isolated organism (30.6%), but the number of isolated coagulase-negative Staphylococcus cases increased significantly in the 2008-2012 cases (P = .04). Antibiotic susceptibility of organisms did not change significantly between the 2 study periods. By using multiple linear stepwise regression analysis, we found that gram-negative bacterial infection played a crucial role in poor visual outcome.

CONCLUSIONS

Contact lens-related microbial keratitis increased in Taiwanese children over time, especially because of the use of overnight orthokeratology. Clinicians must understand the infection background and pay further attention to contact lens use in pediatric patients.

Adverse events during 2 years of daily wear of silicone hydrogels in children

PURPOSE

Type and incidence of adverse events and rate of discontinuations for 2 years of daily wear with silicone hydrogel contact lenses in Chinese children with myopia.

METHODS

Two hundred forty children aged 7 to 14 years were enrolled in a prospective randomized clinical trial from November 2008 to April 2009. Children with myopia of up to -3.50 diopters (D) spherical equivalent with astigmatism less than or equal to -0.75 D were randomized to one commercial and three experimental lens designs of Lotrafilcon B silicone hydrogel lenses (four groups) used bilaterally on a daily wear, monthly replacement schedule. The main outcome measures were incidence per 100 patient-years (incidence, in percentage) of adverse events and rate of discontinuations.

RESULTS

There were no events of microbial keratitis. Fifty-five adverse events (incidence, 14.2%) were seen. There were also 12 recurrent events. The type and incidence percentage were contact lens papillary conjunctivitis (16 events, 4.1%), superior epithelial arcuate lesions (SEALs, six events, 1.5%), corneal erosions (eight events, 2.1%), infiltrative keratitis (five events, 1.3%), asymptomatic infiltrative keratitis (seven events, 1.8%), and asymptomatic infiltrates (13 events, 3.42%). There were differences in the incidence of SEALs between groups (p = 0.023), with the incidence of SEALs being greater with one of the experimental designs. No event resulted in any vision loss. Seventy participants (29.2%) discontinued, with one-third (26 participants, 10.8%) occurring in the first month of lens wear. Discomfort and non-lens-related reasons such as safety concern and disinterest were frequently cited reasons for discontinuations.

CONCLUSIONS

Adverse events with daily wear of silicone hydrogels in children were mainly mechanical in nature, and significant infiltrative events were few. The large number of dropouts in the early days of lens wear and their reasons for discontinuation suggest that adaptation and patient motivation are critical for survival in lens wear.

Risk factors, microbiological profile, and treatment outcomes of pediatric microbial keratitis in a tertiary care hospital in Hong Kong

PURPOSE

To report the risk factors and microbiological profile of pediatric microbial keratitis cases in a tertiary care hospital in Hong Kong.

DESIGN

Retrospective study.

METHODS

Case records of patients <18 years old with microbial keratitis were reviewed over a period of 10 years, between January 2001 and December 2010. Risk factors, microbiological profile, and treatment outcomes were analyzed.

RESULTS

Overall, 18 patients (13 female, 5 male) with unilateral microbial keratitis were included. The mean age was 12.4 years (range: 3-17 years). The most commonly associated risk factor was contact lens wear (15, 83.3%). Seven cases (38.8%) were associated with orthokeratology lenses. Two cases (11.1%) were related to intrinsic keratopathy and 1 case (5.5%) was infected secondary to trauma. Microbiological culture was positive in 16 cases (88.8%). Overall, Pseudomonas sp. was the most commonly isolated organism (10/16, 62.5%), followed by coagulase-negative Staphylococcus (5/16, 31.2%) and Corynebacterium sp. (2/16, 12.5%). All cases responded to intensive medical management with topical antibiotics. One case with posttraumatic keratitis required stepped surgeries with initial tectonic penetrating keratoplasty followed by lens aspiration and retinal detachment repair. At the last follow-up, 13 out of 17 eyes (76.5%) had best-corrected visual acuity ≥20/40.

CONCLUSIONS

Contact lens wear was the most commonly encountered risk factor for the occurrence of microbial keratitis in the pediatric age group in our setting. Orthokeratology remains one of the leading causes of contact lens-related infections. The majority of the cases responded to medical management.).

Paediatric bacterial keratitis cases in Shanghai: microbiological profile, antibiotic susceptibility and visual outcomes

PURPOSE

The purpose of this study was to review the microbiological profile, in vitro antibiotic susceptibility and visual outcomes of paediatric microbial keratitis in Shanghai, China over the past 6 years.

METHODS

Medical records of patients aged ≤16 years were reviewed, who were diagnosed as having bacterial keratitis between 1 January 2005 and 31 December 2010. Bacterial culture results and in vitro antibiotic susceptibility were analysed. A logistic regression analysis was conducted to evaluate the relationship between visual impairment and possible risk factors.

RESULTS

Eighty consecutive cases of paediatric bacterial keratitis cases were included, among which 59 were identified as having positive culture. Staphylococcus epidermidis was the most commonly isolated organism (n=23; 39.0%), followed by Streptococcus pneumoniae (n=11; 18.6%) and Pseudomonas aeruginosa (n=6; 10.2%). Antibiotic sensitivities revealed that tested bacteria had low resistance rates to fluoroquinolones and aminoglycosides (8.3-18.4% and 12.5-24.4%, respectively). Multivariate logistic regression analysis proved that visual impairment was significantly associated with Gram-negative bacterial infection (odds ratio (OR)=7.626; P=0.043) and an increasing number of resistant antibiotics (OR=0.385; P=0.040).

CONCLUSIONS

S. epidermidis was the most common isolated organism in Shanghai paediatric keratitis. The fluoroquinolones and aminoglycosides remained good choices for treating these patients. Gram-negative bacterial infection and an increasing number of resistant antibiotics were associated with worse visual prognoses in paediatric keratitis.

Non-viral microbial keratitis in children

Microbial (non-viral) keratitis is a serious vision-threatening condition. The management of microbial keratitis in children is particularly complicated by the children's inability to cooperate during examinations and the lack of information prior to presentation. Predisposing factors vary according to geographical location and age. Corneal trauma is the leading cause for microbial keratitis in children, followed by systemic and ocular disease. Etiologic agents are most frequently Gram-positive and Gram-negative bacteria commonly found in contact lens-related microbial keratitis. Mycotic keratitis is a major risk factor in tropical weather conditions, particularly when associated with agricultural trauma. Early diagnosis, intensive drug treatment, and timely planned surgical intervention may effectively improve the outcome of pediatric microbial keratitis.

Immunization and nutritional profile of cases with atraumatic microbial keratitis in preschool age group

PURPOSE

To evaluate the role of protein energy malnutrition and immunization profile in cases of atraumatic microbial keratitis in preschool children.

DESIGN

Retrospective case analysis.

METHODS

Case records of all children 5 years of age and younger with atraumatic microbial keratitis treated at the Dr Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi, India, between January and December 2006 were reviewed retrospectively. Main parameters evaluated were age, degree of protein-energy malnutrition, immunization profile, microbiologic profile, and final outcome.

RESULTS

Fifty-four consecutive children were enrolled during the study period. The mean age was 33.69 ± 21.91 months (range, 3 to 60 months). Mean weight on presentation was 10.57 ± 3.87 kg (range, 4 to 17 kg), with an average protein-energy malnutrition grade of 1.77 ± 0.74. The immunization for age was complete in 43 (80%) children. Severe protein-energy malnutrition was associated with the occurrence of bilateral keratitis (P < .001) and incomplete immunization (P < .001). Positive bacterial culture results were obtained in 44 (82%) cases, with Staphylococcus species being the most prevalent isolate (33/44; 75%). Cases requiring emergency corneal transplantation (24%) were associated with severe protein-energy malnutrition (P < .00) and bilaterality (P < .00). In multivariate analyses, cases without severe protein-energy malnutrition were 36% less likely to undergo any kind of surgical intervention (odds ratio, 0.64; 95% confidence interval, 0.04 to 0.91).

CONCLUSIONS

Our study highlights the association of protein-energy malnutrition and immunization profile with the occurrence of atraumatic microbial keratitis in preschool children. Most of these cases required corneal transplantation surgery to preserve the ocular integrity and to restore vision.

Corneal superinfection in acute viral conjunctivitis in young children

Two children suffered from corneal superinfection following acute viral keratoconjunctivitis. Group A beta-hemolytic streptococci were isolated in one child and cultures were negative in the other child. The corneal ulcers resolved with prompt antibiotic therapy, but both patients developed amblyopia. Visual outcome following corneal superinfection in acute viral conjunctivitis may be poor when it occurs in young children.

Ocular infections due to anaerobic bacteria in children

The recent increased recovery of anaerobic bacteria from children has led to greater appreciation of the role these organisms play in pediatric infections at all body sites, including the eye. In studies that employed adequate methods for recovery of anaerobes, they were isolated from approximately one-third of the children with conjunctivitis, half of the time in pure culture. The predominant recovered anaerobes were Clostridium spp., gram-negative anaerobic bacilli, and Peptostreptococcus spp. Anaerobic bacteria were also recovered from patients who wore contact lenses and developed conjunctivitis, and were reported in cases of keratitis. The most frequently recovered anaerobes were Propionibacterium spp., Peptostreptococcus spp., Clostridium spp., Prevotella spp., and Fusobacterium spp. The most frequently recovered anaerobes from dacryocystitis were Peptostreptococcus spp., Propionibacterium spp., Prevotella spp., and Fusobacterium spp. This review describes the microbiology, diagnosis, and management of ocular infections due to anaerobic bacteria in children.

Cholesterol as treatment for pneumococcal keratitis: cholesterol-specific inhibition of pneumolysin in the cornea

PURPOSE

The purpose of this study was to determine whether cholesterol, the host cell receptor for pneumolysin of Streptococcus pneumoniae, could effectively treat pneumococcal keratitis.

METHODS

New Zealand White rabbits were intrastromally injected with 10(5) colony-forming units (CFUs) of S. pneumoniae D39. Corneas were treated with topical drops of 1% cholesterol every 2 hours beginning 25 hours after infection and were examined by slit lamp microscopy 24, 36, and 48 hours after infection. Rabbits were killed, and CFUs were recovered from the corneas after the final slit lamp examination (SLE). Minimal inhibitory concentration (MIC) assays of cholesterol against bacteria were performed. Specific inhibition of pneumolysin by cholesterol in the rabbit cornea was tested by intrastromal injection of pneumolysin with or without cholesterol and was compared with cholesterol inhibition of pneumolysin in vitro using hemolysis assays with rabbit erythrocytes.

RESULTS

Corneas treated with cholesterol had significantly lower SLE scores 48 hours after infection than corneas treated with vehicle (P = 0.0015). Treated corneas also had significantly less log(10) CFUs than vehicle-treated corneas (P = 0.0006). Cholesterol at a 1% concentration was bactericidal to bacteria in vitro, and lower concentrations of cholesterol were partially inhibitory in a concentration-dependent manner. Cholesterol also specifically inhibited 1 mug pneumolysin in vivo and up to 50 ng pneumolysin in vitro.

CONCLUSIONS

Topical cholesterol is an effective treatment for S. pneumoniae keratitis. Cholesterol not only inhibits pneumolysin, it is also bactericidal.

Les abcès graves de la cornée : à propos de 100 cas

PURPOSE

To study predisposing factors, clinical aspects, and microbiological diagnosis in severe microbial keratitis, and to discuss the therapy and visual outcome.

MATERIAL

and methods: A prospective and retrospective study concerning patients presenting microbial keratitis hospitalized in department B of the Hedi Raies Ophthalmology Institute (Tunis, Tunisia), from August 1996 to November 2004.

RESULTS

One hundred patients with microbial keratitis were hospitalized (45 females and 55 males; ranging in age from 11 to 87 years). The principal predisposing factors were ocular surface pathology (30%), ocular trauma (28%), prior ocular surgery (17%), and contact lens wear (8%). The corneal scraping culture was positive in 42% of cases, isolating Gram-positive bacteria (48.6%), Gram-negative bacteria (29.7%), and fungi (21.6%). The majority of our patients (93%) had broad-spectrum topical antibiotics with therapeutic success in 53.8% of cases. Systemic antifungal agents were indicated in 17 cases. Surgery was necessary in 25.8% of cases: therapeutic keratoplasty in five cases and deleted keratoplasty in nine cases. Final visual acuity was equal to or better than at admission in 81% of cases. Anatomic loss of the eye was observed in eight cases (evisceration, six cases; enucleation, two cases).

CONCLUSION

microbial keratitis is a frequent and severe pathology that can lead to blindness. Only early and adapted management can improve the prognosis of severe microbial keratitis.

Polymicrobial keratomycosis in a three-year-old child

PURPOSE

To describe a previously unreported case of polymicrobial mycotic keratitis caused by an association between Candida lusitaniae, C. parapsilosis, and Geotrichum candidum.

METHODS

A three-year-old child with an antecedent trauma with vegetable matter and a prolonged use of corticosteroid eyedrops developed fungal keratitis.

RESULTS

The isolates of the corneal scraping using Sabaraud dextrose agar grew C. lusitaniae, C. parapsilosis, and G. candidum. After topical 0.2% and systemic fluconazole treatment, the corneal lesion resolved with no recurrence.

CONCLUSIONS

Corneal trauma with vegetables and the indiscriminate use of corticosteroids are important risk factors for mycotic keratitis. A combination of topical 0.2% and systemic fluconazole therapy was effective in the treatment of this mycotic association. This is the first report of fungal keratitis caused by C. lusitaniae and G. candidum.

Multivariate Analysis of Childhood Microbial Keratitis in South India

Introduction: Corneal infection is the most common cause of profound ocular morbidity leading to blindness worldwide. Corneal infection in children is difficult to diagnose and treat, as they are unwilling and sometimes unable to cooperate during active management. This study analyses the prevalence, microbiology, demography, therapeutic and visual outcome of infectious microbial keratitis in the paediatric age group seen at a tertiary eye care hospital in south India. Materials and Methods: A retrospective review of all cases presenting with keratitis to the ocular microbiology and cornea service at Aravind Eye Hospital, Coimbatore, from February 1997 to January 2004, was done to screen the patients for microbial keratitis. Their records were further analysed for clinical and microbiological details. Cases with culture-proven non-viral keratitis in children ≤15 years were included in the study. Full ophthalmic examination was performed for all cases. Results: Of the 310 patients who attended the cornea clinic, 97 (31.2%) patients were confirmed to be positive for microbial keratitis. 54.6% of cases were male. The most common predisposing cause of ulceration was trauma (69%) with organic matter. Pure bacterial cultures were obtained from 64 (65.9%) eyes, whereas pure fungal cultures were obtained from 37 (38.1%) eyes. Four (4.1%) eyes showed mixed growth. Conclusion: The most commonly isolated organism was Pseudomonas aeruginosa. The most common predisposing cause of infectious microbial keratitis was corneal trauma. Early stage of diagnosis and formulation of an uncompromising management protocol can prevent profound visual morbidity. Key words: Bacterial, Corneal ulcer, Fungal, Keratitis

Microbial Keratitis at Extremes of Age

PURPOSE

To study the risk factors, clinical presentation, response to treatment and outcome of microbial keratitis occurring in patients at extremes of age (ie, children and the elderly) and to compare them with microbial keratitis affecting the general adult population.

METHODS

In this prospective, nonrandomized, analytical clinical study, all patients presenting with microbial keratitis and undergoing microbiological workup over a 1-year period were evaluated using a dedicated corneal ulcer protocol. Patients were divided into 3 groups based on age: (1) pediatric group if the age was 16 years or younger, (2) elderly group if the age was 65 years or older, and (3) control group if the age was between 17 and 64 years. Features studied included microbiological profile, predisposing factors, clinical presentation, response to treatment, and final visual outcome.

RESULTS

A total of 269 eyes of 269 patients were studied (26 in the pediatric group, 55 in the elderly group, and 188 in the control group). Culture positivity rates were similar in all the groups. The elderly and control groups had a similar incidence of fungal and bacterial keratitis, but the pediatric group had a significantly lower incidence of fungal keratitis (P = 0.001). Trauma was the most common predisposing factor in all groups. Elderly patients tended to present with a higher incidence of central ulcers (P = 0.04), severe ulcers (P = 0.04), and poor visual acuity (P = 0.003) as compared with the control group. The percentage of ulcers healing with medical treatment alone was significantly more in the pediatric group (P = 0.004), while the incidence of poor visual outcome was greater in the elderly group (P = 0.006) as compared with the control group.

CONCLUSIONS

Microbial keratitis in pediatric patients is more likely to be of bacterial etiology, and nonsevere ulcers in this age group have a better chance of resolution with medical therapy alone when compared with that in the general adult population. Conversely, elderly patients with microbial keratitis tend to present with severe, central ulcers with a significant risk of having a poor visual outcome.

The epidemiological features and laboratory results of fungal keratitis: a 10-year review at a referral eye care center in South India

PURPOSE

To report the epidemiological features and laboratory results of 1,352 cases of fungal keratitis diagnosed at the L.V. Prasad Eye Institute (LVPEI) in south India.

METHODS

The medical and microbiology records of 1,352 culture proven cases (1,354 eyes) of fungal keratitis diagnosed at the LVPEI between January 1991 to December 2000 was retrospectively reviewed for demographic features, risk factors, seasonal variation, and laboratory findings.

RESULTS

Males (962) were affected significantly more (p< 0.0001) than females (390). Of 1,352 patients, 853 (64.4%) were in the younger age group (16-49 years). Ocular trauma predisposed to infection in 736 (54.4%) of 1,354 eyes. There was a higher incidence of fungal keratitis during the monsoon and winter than summer. A fungal cause was established by smears of corneal scrapings in 1,277 (95.4%) eyes. The potassium hydroxide preparation (KOH), Calcofluor white (CFW), Gram-, and Giemsa-stained smears revealed fungus in 1,219 (91.0%), 1,224 (91.4%), 1,181 (88.2%), and 1,139 (85.1%) eyes, respectively. Fusarium(506, 37.2%) and Aspergillus species (417, 30.7%) predominated the hyaline fungal spectrum (1,133) and Curvularia species (39, 2.8%) were the highest among the dematiaceous isolates (218).

CONCLUSIONS

To the best of our knowledge, this review presents the epidemiological features and laboratory results of the largest series of fungal keratitis ever reported in the literature. Keratomycosis is predominant in young adults with trauma as the major predisposing factor. With fungal keratitis being a major ophthalmologic problem in the tropical regions of the world, data available on the epidemiological features of a large series would greatly help medical practitioners at primary and secondary health care centers in the management of the disease. A simple KOH preparation of corneal scraping alone is highly beneficial in confirming the diagnosis.

Corneal ulceration in pediatric patients: a brief overview of progress in topical treatment

Pediatric microbial keratitis is a rare but potentially devastating condition. The condition is similar to adult microbial keratitis, but is often characterized by a more severe inflammatory response. The micro-organisms that cause microbial keratitis in children are similar to the causative agents in adults, with herpes simplex and bacteria being the predominant causative agents, and fungi being less frequent. Of the bacterial pathogens, Pseudomonas aeruginosa, Staphylococcus aureus and alpha-hemolytic streptococci are common. The risk factors for pediatric keratitis include colonization of the eyes during birth and trauma to the cornea. Certain microbial factors involved in microbial keratitis are common to all micro-organisms, including adhesion to the cornea, penetration into the cornea, destruction of the corneal stroma (usually by microbial and/or host proteases), and recruitment of white blood cells to help defend the eye. Specific inflammatory responses that occur during pediatric microbial keratitis are not known in detail, but it is likely that cytokines and polymorphonuclear leucocytes are major factors, as they are in adult microbial keratitis. Treatment for pediatric microbial keratitis is usually the same as treatment for adult microbial keratitis; topical application of antimicrobial agents initially, followed by application of anti-inflammatory agents. With pediatric microbial keratitis, extra care must be taken to ensure nontoxicity due to blood adsorption. New microbial keratitis treatments are being developed and these mainly focus on new antimicrobials, antivirulence agents (such as vaccination against microbial toxins) or specific anti-inflammatory agents. There remains a clear need for increased research into the specific responses during microbial keratitis in children which will help progress new therapies as well as the development of new antimicrobials, especially new antifungal therapies.

Clinical and microbiological profile of Bacillus keratitis

PURPOSE

To examine the clinical and microbiological profile of Bacillus keratitis.

METHODS

A retrospective review was done of all medical and laboratory records of patients with infectious keratitis in an urban tertiary level eye-care center in South India between January 1991 and June 1997.

RESULTS

Nineteen eyes of 17 patients having microbiologically proven Bacillus keratitis were reviewed. The mean age of the patients was 32.64 years (range, 3-70). The duration of symptoms ranged from 1 day to 3 months, with 11 eyes seen within a week of onset of symptoms. Trauma (five eyes), lagophthalmos (two eyes), topical corticosteroid therapy (one eye), bullous keratopathy (two eyes), previous corneal scars (two eyes), and diabetes (one eye) were identified as predisposing factors. Severe corneal features, disproportionate to the duration of symptoms, were present in most of the eyes. Gram stain of corneal scrapings showed variably stained bacilli in eight (42.1%) cases. Polymicrobial infection was present in six eyes (two fungal, four bacterial). Of the 16 isolates tested for in vitro antibiotic susceptibility, 100% were sensitive to gentamicin, 15 (93.75%) were sensitive to ciprofloxacin and norfloxacin, 14 (87.5%) were sensitive to chloramphenicol, and 10 (62.5%) were sensitive to cefazolin. Whereas 12 (63.1%) eyes required only medical therapy, adjunctive procedures were required in seven (36.8%) eyes. The ulcers healed (mean time to healing, 37.4+/-28.6 days) in 16 eyes (lost to follow-up, three). Visual acuity had improved after treatment in 10 (71.4%) of 14 eyes in whom vision could be recorded.

CONCLUSION

Bacillus is an unusual pathogen in the clinical setting of infectious keratitis. The infection is mostly amenable to treatment with commonly used antibiotics, and the final outcome is often satisfactory.

Antimicrobial management of presumed microbial keratitis: guidelines for treatment of central and peripheral ulcers

AIMS

To determine the quantitative relation between the major risk factors for microbial keratitis of previous ocular surface disease and contact lens wear and central and peripheral infiltration, often associated with ulceration, in order to establish a rational chemotherapeutic management algorithm.

METHODS

Data from 55 patients were collected over a 10 month period. All cases of presumed microbial keratitis where corneal scrapes had been subjected to microbiological examination were included. Risk factor data and laboratory outcome were recorded. Antimicrobial regimens used to treat each patient were documented.

RESULTS

57 episodes of presumed microbial keratitis were identified from 55 patients, 24 male and 31 female. There were 30 central infiltrates and 27 peripheral infiltrates of which 28 were culture positive (73% of central infiltrates, 22% of peripheral infiltrates). 26 patients had worn contact lenses of whom 12 had culture positive scrapes (9/14 for central infiltrates, 3/12 for peripheral infiltrates). 31 patients had an ocular surface disease of whom five previous herpes simplex virus keratitis patients developed secondary bacterial infection. Anterior chamber activity and an infiltrate size > or = 4 mm2 were more common with culture positive central infiltrates than peripheral infiltrates (chi 2 test = 11.98, p < 0.001).

CONCLUSIONS

Predisposing factors for "presumed" microbial keratitis, either central or peripheral, were: ocular surface disease (26/57 = 45.6%), contact lens wear (26/57 = 45.6%), and previous trauma (5/57 = 8.8%). Larger ulceration (> or = 4 mm2) with inflammation was more often associated with positive culture results for central infiltration. None of these four variables (contact lens wear, ocular surface disease, ulcer size, anterior chamber activity) were of intrinsic value in predicting if a peripheral infiltrate would yield identifiable micro-organisms. Successful management of presumed microbial keratitis is aided by a logical approach to therapy, with the use of a defined algorithm of first and second line broad spectrum antimicrobials, for application at each stage of the investigative and treatment process considering central and peripheral infiltration separately.

Microbial keratitis in children

OBJECTIVE

Microbial keratitis is a major cause of corneal blindness worldwide. This problem is particularly relevant to children, because most of their visual life is ahead of them, and they are uniquely at risk for irreversible ocular deficits, such as those resulting from amblyopia. The objective of this study was to determine the etiologic agents and predisposing factors in childhood infectious keratitis and to examine the outcome of treatment in terms of structure and visual acuity.

DESIGN

The study design was a retrospective cases series.

PARTICIPANTS

The authors studied 113 eyes in 107 children 16 years of age and younger who were treated for (nonviral) microbial keratitis at the LV Prasad Eye Institute in Hyderabad, India, during the 4.5-year period between February 1, 1991, and June 30, 1995.

INTERVENTION

The patients who met the following criteria were included in the study: (1) corneal stromal infiltrate was present on slit-lamp examination; and (2) a corneal scraping was taken at the time of examination for suspected microbial keratitis.

MAIN OUTCOME MEASURES

Etiologic micro-organisms, predisposing factors, treatment method, structural treatment outcome, and visual acuity treatment outcome of the infectious keratitis episode were measured.

RESULTS

The principal predisposing factors identified in this study were trauma (21.2%), ocular disease (17.7%), systemic disease (15.9%), and prior penetrating keratoplasty in the same eye (8.8%). Vitamin A deficiency was an important factor within the category of severe systemic disease, and contact lens wear was not involved in any of the cases. A total of 85 organisms were isolated in cultures of corneal scrapings from 64 (56.6%) of the 113 cases. Staphylococcus species (43.7%), Streptococcus pneumoniae (18.8%), and fungi (17.2%) were the most common isolates. Eighteen eyes (15.9%) required surgery, and 28 (36.4%) of the 77 patients on whom visual acuity was assessed at last follow-up achieved an unaided visual acuity of 20/60 or better at last follow-up.

CONCLUSION

This work represents the largest recent study on childhood (nonviral) microbial keratitis, its management, and treatment outcomes. In this study, amblyopia is highlighted as a potentially significant sequela of childhood microbial keratitis. Identification of the appropriate predisposing factors, etiologic microbial organisms, and treatment outcome from this study may aid in early recognition and treatment of microbial keratitis in children.