Paediatric infectious keratitis at tertiary referral centres in Vancouver, Canada

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.

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.

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 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.

Impact of topical corticosteroid pretreatment on susceptibility of the injured murine cornea to Pseudomonas aeruginosa colonization and infection

Research with animal models of Pseudomonas aeruginosa keratitis has shown that use of a topical corticosteroid alone against an established infection can significantly increase the number of colonizing bacteria or worsen clinical disease. Moreover, retrospective analysis has suggested that corticosteroid use in humans is associated with an increased risk of keratitis in eyes with pre-existing disease. Thus, while corticosteroids are often used to reduce ocular inflammation in the absence of infection, the risk of opportunistic infection remains a concern. However, the effect of corticosteroids on the intrinsic barrier function of uninfected corneas is unknown. Here, we tested if short-term topical corticosteroid treatment of an uninfected murine cornea would increase susceptibility to P. aeruginosa colonization or infection after epithelial injury. Topical prednisolone acetate (1%) was administered to one eye of C57BL/6 mice three times a day for 3 days; control eyes were treated with sterile PBS. Prior to inoculation with a cytotoxic P. aeruginosa corneal isolate strain 6206, corneas were subject to superficial-injury by tissue paper blotting, or scratch-injured followed by 12 h of healing. Previously we have shown that blotting renders mouse corneas susceptible to P. aeruginosa adhesion, but not infection, while 12 h healing reduces susceptibility to infection after scratching. Corneas were evaluated at 48 h for bacterial colonization and microbial keratitis (MK). To monitor impact on wound healing, corneal integrity was examined by fluorescein staining immediately after scarification and after 12 h healing. For both the tissue paper blotting and scratch-injury models, there was no significant difference in P. aeruginosa colonization at 48 h between corticosteroid-pretreated eyes and controls. With the blotting model, one case of MK was observed in a control (PBS-pretreated) cornea; none in corticosteroid-pretreated corneas. With the 12 h healing model, MK occurred in 6 of 17 corticosteroid-pretreated eyes versus 2 of 17 controls, a difference not statistically significant. Corticosteroid-pretreated eyes showed greater fluorescein staining 12 h after scarification injury, but this did not coincide with increased colonization or MK. Together, these data show that short-term topical corticosteroid therapy on an uninfected murine cornea does not necessarily enhance its susceptibility to P. aeruginosa colonization or infection after injury, even when it induces fluorescein staining.

Infectious keratitis and orthokeratology lens use: a systematic review

PURPOSE

Myopia is a prevalent condition among Asians. Orthokeratology lens has gained popularity as a method of myopia control. This systematic review is to summarize the clinical profile of infectious keratitis in association with orthokeratology lens wear.

METHODS

We searched in the PubMed and EMBASE for articles adopting the search strategy "(orthokeratology lens OR orthokeratology) AND (bacterial eye infection OR keratitis OR cornea ulcer OR microbial keratitis OR bacterial keratitis)", from the start date of the databases to August 23, 2016. Articles reporting infectious keratitis in orthokeratology lens users with data of individual cases were considered eligible for this systematic review. We recorded the outcome measures including method of diagnosis, etiological agents, duration and mode of treatment and treatment outcomes.

RESULTS

Our literature search yielded 172 papers. After removing duplicated and irrelevant reports, we included 29 articles for data analysis, involving 173 eyes. Among all reported cases, the mean age at presentation was 15.4 ± 6.2 years, with a female preponderance (male-to-female ratio 1:1.7). Positive microbiological cultures were reported in 69.4% of cases, with Pseudomonas aeruginosa and Acanthamoeba being the most common etiological agents. The mean duration of hospitalization was 7.7 ± 6.7 days. Mean LogMAR visual acuity at presentation was 1.17 ± 0.78, increased to 0.33 ± 0.41 at final visit (p < 0.001).

CONCLUSIONS

Despite early intervention and treatment, the majority of infections resulted in the formation of corneal scars and almost 10% of eyes needed surgical treatment. Timely awareness and treatment of keratitis should be emphasized to the users.