Paediatric infectious keratitis: a case series of 107 children presenting to a tertiary referral centre

Scoping review: Reporting characteristics for the safety of contact lenses in the pediatric population

SIGNIFICANCE

Contact lenses are an increasingly popular option for correcting pediatric refractive error due to increased awareness of interventions to slow myopia progression. With limited information on the safety profiles of contact lenses in children, it is important to characterize the current understanding and promote this device's safe and effective use.

PURPOSE

This scoping review evaluates characteristics of the current literature that have examined the safety of contact lenses in pediatric patients. It provides future directions for systematic reviews and identifies any gaps in the current literature or areas for future research.

METHODS

Literature searches in MEDLINE via PubMed, EMBASE, The Cochrane Library, trial registries, and U.S. Food and Drug Administration clinical trial documentation were performed. Included studies (i.e., experimental and quasi-experimental studies; observational studies including prospective and retrospective cohort, case-control, and analytical cross-sectional studies, and case series of 30 or more participants) reported safety and/or complications of the use of any contact lens for correcting refractive error in children (0 to 18 years). Two independent reviewers first screened the titles and abstracts, and then full-text reports for eligibility. Conflicts in eligibility were resolved by discussions with a third reviewer. Two independent reviewers extracted data, including details about the participants, context, study methods, and key findings relevant to the review question.

RESULTS

This scoping review included 73 studies from 10 countries using different contact lens modalities, primarily orthokeratology and soft contact lenses, in children (6 to 18 years). The most common adverse event reported by the studies was corneal staining (60% orthokeratology, 45% soft contact lens).

CONCLUSIONS

The need for uniform reporting standards for adverse events poses challenges for comprehensive data synthesis. However, this scoping review identified a sufficient number of studies for a future systematic review to quantify the risks associated with orthokeratology and soft contact lens use 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.

Pediatric bacterial keratitis: clinical features, causative organisms, and outcome during a 13-year study period

OBJECTIVE

To review the clinical features, causative organisms, complications, and outcomes of patients with pediatric bacterial keratitis at a tertiary care eye hospital.

METHODS

We conducted a retrospective study at a tertiary care eye centre on clinically diagnosed pediatric patients with bacterial keratitis between 2007 and 2019. Poor outcomes were labelled if any of the following were present: final best-corrected visual acuity worse than 20/200, a drop in best-corrected visual acuity by 1 line or more, perforated corneas, endophthalmitis, and graft failure.

RESULTS

The study included 43 cases of bacterial keratitis. Female and male patients represented 60.5% and 39.5% of the sample, respectively, with a mean age of 9.3 ± 5.9 years. The rate of culture positivity was 60.5%. The most common causative organisms were coagulase-negative Staphylococcus (23.1%), Pseudomonas (23.1%), and Streptococcus pneumoniae (19.2%). Culture-positive bacterial keratitis was associated with infiltrates ≥2 mm (p = 0.039), as determined by the results of multivariate analysis. Gram-positive and gram-negative bacteria exhibited 100% sensitivity to the tested fluoroquinolones. Complications included visually significant scars (55.8%), cataracts (14.0%), perforations (9.3%), corneal neovascularization (7.0%), nonhealing epithelial defects (7.0%), and endophthalmitis (4.7%). Corneal perforation was associated with the development of endophthalmitis (p < 0.001). On multivariate analysis, the only factor associated with a poor outcome was poor presenting visual acuity (p = 0.020).

CONCLUSION

Gram-positive bacteria were the most common cause of pediatric microbial keratitis. Positive cultures were associated with larger infiltrates. The only adverse prognostic factor was poor presenting vision.

Incidence and clinical characteristics of paediatric keratitis

BACKGROUND/AIMS

To report the incidence and clinical characteristics of paediatric keratitis diagnosed over a 10-year period in a well-defined population.

DESIGN

Retrospective, population-based study.

METHODS

Setting: multicentre.

POPULATION

patients (<19 years) diagnosed with keratitis as residents of Olmsted County from 1 January 2000, through 31 December 2009.

MAIN OUTCOME MEASURES

calculated annual age-specific and gender-specific incidence rates, demographic information and initial and final visual acuity.

RESULTS

A total of 294 diagnoses of keratitis occurred in 285 children during the 10-year period, yielding an incidence of 78.0 per 100 000 younger than 19 years (95% CI 69.0 to 87.1) or approximately 1 in 1282 children. The incidence increased throughout the 10-year study period (p<0.001). The mean age at diagnosis was 15.3 years (range, 0.2-18.9) and 172 (60.4%) were women. The observed forms included keratitis due to contact lens wear in 134 (45.6%), infectious keratitis in 72 (24.5%), keratitis not otherwise specified in 65 (22.1%) and keratitis sicca in 23 (7.8%). The visual acuity was reduced to ≤20/40 in 61 (21.4) of the 285 patients at the initial examination and in 24 (8.4%) at the final examination. Children with infectious keratitis had the poorest presenting vision and the best final vision, whereas the reverse was true for those with keratitis sicca.

CONCLUSIONS

Keratitis, regardless of aetiology, was observed in approximately 1 in 1300 children by 19 years of age in this population-based cohort. Nearly half were related to contact lens wear and a decrease in vision to ≤ 20/40 occurred in 1 in 12 patients.

Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience

Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.

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.

Pediatric Microbial Keratitis: Identification of Clinical Biomarkers for Prognosis and Outcome of 218 Cases From 2009 to 2019

PURPOSE

The aim of this study was to analyze the risk factors, microbiological profile, and treatment efficacy in pediatric microbial keratitis (MK) and to identify clinical biomarkers prognosticating outcome.

METHODS

A retrospective analysis was conducted from patients younger than 16 years with MK-excluding viral, marginal, or interstitial keratitis. Data pertaining to predisposing factors, symptom duration, prior treatment, ulcer characteristics, microbiological profile, time to resolution, and final outcome were recorded. Statistical analysis was performed. The mixed-effects linear regression model with random intercept was used to evaluate factors affecting time to resolution.

RESULTS

Among 218 episodes of 215 pediatric patients with MK, the geometric mean of central [median 3 mm, interquartile range (IQR) 1-4.3 mm] and peripheral ulcers (median 1 mm, IQR 1-2.5 mm) was significantly different ( P < 0.0001). Organisms identified were bacteria (56.9%), fungi (31.5%), and acanthamoebae (2.3%). Of 172 cases (78.8%), which resolved in a median resolution time of 22 days (IQR, 11-44 days), 107 (81.6%) with absent/negative microbiology healed on empirical therapy. On multivariate analysis, peripheral ulcers and geometric mean ulcer size affected time to resolution. Significantly higher percentage of eyes, which worsened or perforated, were on topical steroids compared with those which healed (31.8% vs. 9.2%, P = 0.0061).

CONCLUSIONS

Good outcome even in culture negative cases suggests empirical therapy may be instituted for nonsevere peripheral pediatric MK; however, the importance of a microbiological workup cannot be underscored enough. Ulcer location and geometric mean size of ulcer may be used as clinical prognostic markers for resolution.

Incidence and outcomes of microbial keratitis after cyclophotocoagulation to treat childhood refractory glaucoma

PURPOSE

To report the incidence and outcomes of microbial keratitis (MK) following cyclophotocoagulation (CPC) for treatment of refractory childhood glaucoma (CG) at a single center over a period of 6 years.

METHODS

In this cohort study, the medical records of children with CG who underwent CPC and subsequently presented with MK from 2014 to 2020 were reviewed retrospectively. Data were collected on age, type of glaucoma, surgeries before MK, CPC parameters, interval between CPC and MK, presenting symptoms of MK, infiltrate location, bacterial isolates, MK treatment, and outcomes.

RESULTS

Among the 312 children who underwent CPC during the study period, 37 eyes of 33 children had MK, with an incidence of 1.8% (95% CI, 0.3-3.2). The median interval between CPC and MK was 4 years (IQR, 2.7-7.4). CPC was repeated once in 20 eyes (54%) and twice in 4 (11%). In 20 eyes, there was no pain at MK onset. The primary isolates were Streptococcus pneumoniae (12/27 [22%]) and Staphylococcus epidermis (8/27 [30%]). MK resolved in 17 eyes (46%) after treatment; 8 eyes (22%) underwent evisceration or had phthisis, and keratoplasty failed in 6 eyes (16%). The absence of pain at presentation with MK was negatively associated with resolution (OR = 5.0 [95% CI, 1.1-23.8]; P = 0.04).

CONCLUSIONS

The absence of pain at MK onset may be a proxy for neurotrophic keratitis after CPC and is linked to poor response to management.

Severe corneal abscess: epidemiology and clinicobacteriological aspect

AIM

To assess epidemiological, clinical and microbiological characteristics of patients presenting with a clinically diagnosed severe corneal abscess at the Farhat Hached Hospital Department of Ophthalmology (Sousse).

METHODS

A retrospective, descriptive and anlalytic study of patients presenting severe corneal abscess was conducted over 5 years, from january 1st of 2013 to septembre 3Oth of 2017. The epidemiological, clinical and microbiological aspects, were analyzed.

RESULTS

one hundred and one of of 100 patients were presented severe corneal abscess. The mean age was 54,1 ans years old. The mean delay for referral was 15,5days. The most frequent Risk factor was chronic keratopathy noted in 59% ofcases. Corneal trauma was noted in (30%) and use of contact lenses in (12%).Visual acuity was less than 1/10 in 72% of the patients. Bacteriological cultures isolated an organism in 39.9 % of cases. Coagulase-negative Staphylococcus (23,3%), Pseudomonas aeruginosa (16,7%), streptococcus (13,3%) were the most frequent species that have been found.

CONCLUSION

A good preliminary analysis of the risk factors, the mode of infection, and the appropriate search for the incriminated germs, allow secondarily an adequate management of the severe corneal abscesses.

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

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Advances in the Microbiology of Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an opportunistic pathogen of significant concern to susceptible patient populations. This pathogen can cause nosocomial and community-acquired respiratory and bloodstream infections and various other infections in humans. Sources include water, plant rhizospheres, animals, and foods. Studies of the genetic heterogeneity of S. maltophilia strains have identified several new genogroups and suggested adaptation of this pathogen to its habitats. The mechanisms used by S. maltophilia during pathogenesis continue to be uncovered and explored. S. maltophilia virulence factors include use of motility, biofilm formation, iron acquisition mechanisms, outer membrane components, protein secretion systems, extracellular enzymes, and antimicrobial resistance mechanisms. S. maltophilia is intrinsically drug resistant to an array of different antibiotics and uses a broad arsenal to protect itself against antimicrobials. Surveillance studies have recorded increases in drug resistance for S. maltophilia, prompting new strategies to be developed against this opportunist. The interactions of this environmental bacterium with other microorganisms are being elucidated. S. maltophilia and its products have applications in biotechnology, including agriculture, biocontrol, and bioremediation.

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.