Incidence Of Microbial Keratitis Research Articles

The Epidemiological Profile and Predisposing Factors of Microbial Keratitis Over a 10-Year Period at a Tertiary Hospital in Central Saudi Arabia.

To evaluate the demographic and predisposing factors and clinical presentation of microbial keratitis (MK) patients over 10 years at a tertiary hospital in central Saudi Arabia. In 2020, a retrospective review of data from clinical and pathology departments from 2010 to 2019 was conducted. Demography includes age, gender, residence, and the risk factor of microbial keratitis, clinical features, and organism profile as number and percentage. We reviewed 181 eyes of 179 patients with microbial keratitis. The mean age was 40.1 years. Contact lens usage(55; 30%), ocular trauma (30; 16.5%), and ocular surface diseases(42; 23.2%) were the main predisposing factors. Hypopyon was noted in 60 (33%) eyes, impaired vision at presentation was observed in 78 (43%) eyes, and endophthalmitis with microbial keratitis was noted in eight (4.4%) eyes at presentation. Ninety-eight (54,1%) cases were culture positive, while gram-positive organisms were seen in 50 (27.6%) eyes, gram-negative organisms in 35 (19.3%) patients, and fungi in 13 (7.2%) patients. Microbial keratitis was central in 67 (37%), paracentral in 94 (52%), and peripheral in 20 (11.3%) patients. All instances of fungal keratitis occurred in the eyes of men who work in the agriculture field. Standard operating procedures to manage microbial keratitis at primary and secondary eye care levels are recommended. Health promotion to prevent trauma, appropriate useof contact lens, and early treatmentcould prevent the incidence ofmicrobial keratitis.

Good Outcome of Corneal Ulcer With Hypopion After Long Use of Contact Lens

Introduction: Microbial keratitis is a corneal infection caused by microorganisms and is characterized by a profound corneal epithelial defect that infects the cornea and causes severe and progressive visual loss. In recent years, the incidence of microbial keratitis has increased. One of the critical risk factors for increasing this incidence is using contact lenses. As the number of contact lens users increases, the number of corneal ulcers associated with contact lenses also increases. Case Presentation: A 25-year-old man was admitted to the emergency department with a complaint of gradually blurry vision in his left eye four days after using contact lenses for overnight uses since the previous few days and did not routinely clean contact lenses or replace contact lens cleaning fluid. The visual acuity of the patient's left eye was hand movement with conjunctival and pericorneal injection in the conjunctiva and 6 x 7 mm stromal level infiltrate, blurred margin, and whitish color in the center of the cornea. After 28 days of treatment, an examination showed the patient's left eye improvement. Visual acuity was 3/60, conjunctival injection disappeared, corneal swelling significantly resolved, hypopyon disappeared, and ulcer completely re-epithelialized. Conclusions: Empirical therapy with broad-spectrum antibiotics and other adjunctive therapy has a good outcome in treating contact lens-related corneal ulcers.

Incidence of Corneal Adverse Events in Children Wearing Soft Contact Lenses.

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. 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. 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). 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.

Spectrum of Microbial Keratitis in the Mid-Western Region of Nepal

Introduction: Microbial keratitis is sight threatening infective keratitis caused by non-viral pathogens like bacteria, fungus or protozoa which may lead to blindness when neglected. It is the most common cause of unilateral corneal blindness which is a major public health concern for developing countries. Incidence of microbial keratitis in Nepal is higher (799/100000 per year) compared to developed countries like United States (11/100000 per year) due to varying epidemiological factors. Early clinical diagnosis, initiation of proper antibiotic therapy, identification of causative microorganism and management of predisposing factors together are necessary for rapid recovery and prevention of severe visual loss. 
 Methods: This was a retrospective study of all consecutive patients diagnosed with suspected microbial keratitis and subjected to corneal scrapping in Cornea Department of Rapti Eye Hospital who attended during November 2021 to October 2022. The major outcome measures studied were predisposing factors, microbial spectrum, antibiotic sensitivity, treatment outcomes and surgical interventions required.
 Results: A total of 68 eyes of 68 cases diagnosed with microbial keratitis and subjected to corneal scrapping were enrolled in the study. Mean age of the study participants was 49.6 ± 19.6 years and male to female ratio was 1.96:1. Ocular trauma was the most common predisposing factor (48.5% of cases) followed by use of steroid. Culture was positive in 36.8% of cases of which bacterial isolates were more common than fungal isolates. Streptococcus pneumoniae (37%) and Fusarium species (44.44%) were most common organisms among the bacterial and fungal isolates respectively. 
 Conclusions: Streptococcus pneumoniae and Fusarium species are the most common bacterial and fungal species causing microbial keratitis in the mid-western region of Nepal with ocular trauma being the commonest predisposing factor. Cefazolin and fluoroquinolones are most effective antibiotics for Gram positive and Gram negative organisms.

Impact of the COVID-19 Pandemic on the Incidence and Characteristics of Culture-Positive Microbial Keratitis at a Tertiary Eye Hospital in the UK.

PurposeThe COVID-19 pandemic has led to drastic changes to the daily lives of those living in the United Kingdom. We hypothesized that the effect of the imposed lockdown on both behaviour and social interaction has the potential to influence the characteristics of microbial keratitis presenting locally to Manchester Royal Eye Hospital — a major tertiary eye centre in the UK.MethodsWe conducted a retrospective case-note review of all positive corneal scrape cultures identified by our local microbiology laboratory during the year since the announcement of lockdown measures in the UK (23 March 2020 to 23 March 2021). Culture results were compared with previously collated, published “baseline” data from prior to the onset of the COVID-19 pandemic (2004–2019). Statistical analysis was undertaken, predominantly looking at the incidence of microbial keratitis and the variety of cultured pathogens.ResultsA total of 6243 corneal scrape results were reviewed. Comparison of data between the COVID-19 pandemic and subsequent lockdown did not show a significant change in the incidence of culture-positive microbial keratitis: mean annual positive samples during 2004–2019 were 128 (35%) vs 91 (29%) during lockdown (P=0.096). No statistically significant shifts in the incidence of organism subtypes — fungi, acanthamoeba, Gram-positive bacteria, or Gram negative bacteria — were identified (P=0.196, 1, 0.366, and 0.087, respectively).ConclusionContrary to our hypothesis, our results suggest that the COVID-19 pandemic did not alter the incidence or characteristics of microbial keratitis presenting to Manchester Royal Eye Hospital in the year following the implementation of lockdown measures in the UK.

Depth Effect of Cold Atmospheric Pressure Plasma in Keratitis Therapy: A Corneal Stroma Tissue Model

The incidence of microbial keratitis has been increasing and is now 28 cases/100,000 inhabitants; this may be due to the more frequent use of contact lenses. Keratitis can lead to visual impairment and in severe cases with endophthalmitis to enucleation of the affected eye. As microorganisms are becoming more resistant to antibiotic therapy, there is a need for new therapeutic strategies. Cold atmospheric pressure plasma has already been successfully used to disinfect surfaces. This study investigates the efficacy of cold atmospheric pressure plasma against Escherichia coli in a depth-resolved corneal stroma tissue model.

Microbial keratitis and clinical outcomes following penetrating and endothelial keratoplasty.

The goal of this study was to review the incidence, risk factors and outcomes of microbial keratitis after penetrating keratoplasty (PK) and endothelial keratoplasty (EK). The electronic medical records at Wills Eye Hospital were queried for cases of microbial keratitis following PK or EK performed between 1 May 2007 and 1 September 2018. Charts were reviewed to obtain demographic data, transplant characteristics, details of microbial keratitis, graft survival and clinical outcomes. During the study period, 2098 transplants were performed in 1601 patients. Of these, 1267 (60.4%) were PKs and 831 (39.6%) were EKs. We identified 86 (4.1%) cases of subsequent microbial keratitis. The incidence of microbial keratitis after PK was significantly higher than after EK (5.9% versus 1.3%; p=0.005). Furthermore, the rate of infection was higher after repeat transplants (either PK or EK) compared to initial keratoplasties (5.5% versus 3.4%; p=0.02). Twenty-six (32.1%) grafts remained clear at most recent follow-up after microbial keratitis, and the proportion of clear grafts was higher after EK than PK (66.7% versus 27.8%; p=0.03). Rates of microbial keratitis were significantly higher after PK compared to EK, and repeat transplantation was a risk factor for microbial keratitis. To the best of our knowledge, there is no prior study in the literature evaluating microbial keratitis rates after PK and EK and comparing outcomes.

The Safety of Soft Contact Lenses in Children.

ABSTRACTPurposeThere is increasing interest in fitting children with soft contact lenses. This review collates data from a range of studies to estimate the incidence of complications, specifically corneal infiltrative events and microbial keratitis, in patients under the age of 18 years.MethodsPeer-review papers were identified using PubMed and the Web of Science. A broad range of studies are summarized including large-scale epidemiological studies of contact lens–related complications, hospital-based case series, long- and short-term prospective studies, and multicenter retrospective studies.ResultsNine prospective studies representing 1800 patient years of wear in 7- to 19-year-olds include safety outcomes. In three large prospective studies representing between 159 and 723 patient years of soft contact lens wear in patients 8 to 14 years, the incidence of corneal infiltrative events is up to 136 per 10,000 years. Data from a large retrospective study show similar rates of corneal infiltrative events: 97 per 10,000 years in 8- to 12-year-olds (based on 411 patient years of wear) and 335 per 10,000 years in 13- to 17-year-olds (based on 1372 patient years of wear). None of the prospective studies report any cases of microbial keratitis. Five clinical studies where safety data are not reported constitute a further 493 patient years. One retrospective study found no cases of microbial keratitis occurred in 8- to 12-year-olds (411 patient years) and an incidence of 15 per 10,000 patient years in 13- to 17-year-olds (1372 patient years)—no higher than the incidence of microbial keratitis in adults wearing soft contact lenses on an overnight basis.ConclusionsThe overall picture is that the incidence of corneal infiltrative events in children is no higher than in adults, and in the youngest age range of 8 to 11 years, it may be markedly lower.

Microbial Keratitis and Endophthalmitis After the Boston Type 1 Keratoprosthesis.

To determine the incidence, ocular surface disease associations, microbiological profile, and clinical course of postoperative infections after implantation of the Boston type 1 keratoprosthesis (KPro-1). A retrospective chart review was conducted of all cases of the KPro-1 performed at a tertiary eye care center between January 1, 2008, and December 31, 2014. Seventy-five KPro-1 procedures were included in the analysis. Postoperative infections occurred in 13 eyes (17.3%) with an incidence of 0.064 cases per eye-year. The Kaplan-Meier probability of an infection-free graft was 0.96, 0.90, 0.88, 0.87, and 0.86 at years 1 through 5, respectively. The rate of infections was greater in eyes with ocular surface disease (26.3% vs. 8.1%, P = 0.06), especially in those with a history of chemical or thermal injury or herpes zoster keratopathy (P = 0.001). There were 8 cases (10.7%) of microbial keratitis due to either fungi (5 cases) or bacteria (3 cases). There were 7 cases (9.3%) of endophthalmitis due to bacteria (5 cases) or intraocular extension of fungal keratitis (2 cases). The incidence of microbial keratitis and endophthalmitis was 0.034 and 0.03 cases per eye-year, respectively. Therapeutic management of the infected eyes required graft and device removal in 7 eyes (53.8%). After completion of microbiologic treatment, 7 eyes (53.8%) had lost more than 2 lines of the best-corrected preinfection visual acuity, including 5 eyes with endophthalmitis that had hand motion vision or worse. Postoperative infections are a serious issue that compromises device retention and visual outcomes after keratoprosthesis implantation.

Microbial Keratitis after Boston Type I Keratoprosthesis Implantation: Incidence, Organisms, Risk Factors, and Outcomes

To identify the incidence of and risk factors for microbial keratitis after implantation of the Boston type I keratoprosthesis (Massachusetts Eye and Ear Infirmary, Boston, MA). Retrospective, single-surgeon consecutive case series. A total of 105 patients (125 keratoprosthesis procedures in 110 eyes) who underwent Boston type I keratoprosthesis implantation at the Jules Stein Eye Institute between May 1, 2004, and April 1, 2012. Data regarding ocular history, relevant intraoperative data, postoperative management, and outcomes were collected for each procedure. Risk factor analyses were performed using the Fisher exact test, log-rank test, and hazard ratio (HR). Incidence of microbial keratitis, organisms responsible, risk factors, and outcomes. During the period under review, 20 presumed infectious infiltrates were diagnosed in 15 eyes (13.6%) of 15 patients (14.3%), for a rate of 0.073 infections per eye-year. The rate of culture-positive bacterial keratitis was 0.022 infections per eye-year, and the rate of culture-positive fungal keratitis was 0.015 infections per eye-year. Topical vancomycin use, topical steroid use, and contact lens wear did not increase the incidence of infectious keratitis, but prolonged vancomycin use was associated with an increased risk for fungal keratitis and infectious keratitis overall. Persistent corneal epithelial defect formation also was associated with an increased incidence of fungal keratitis and infectious keratitis overall. There were no cases of endophthalmitis resulting from infectious keratitis. Infectious keratitis develops in 13.6% of eyes after keratoprosthesis implantation, with a similar rate of culture-positive bacterial and fungal keratitis. The observed rate of microbial keratitis suggests the need for additional topical antimicrobial prophylaxis after keratoprosthesis implantation in eyes at higher risk, such as those with persistent corneal epithelial defect formation or prolonged vancomycin use.

The effects of silicone hydrogel lens wear on the corneal epithelium and risk for microbial keratitis.

Previous studies using animal models and human clinical trials have demonstrated that the use of low-oxygen-transmissible contact lens materials produce corneal epithelial surface damage resulting in increased Pseudomonas aeruginosa (PA) adhesion and raft-mediated internalization into surface corneal epithelial cells. These findings led to the testable clinical predictions that (1) microbial keratitis (MK) risk is expected to be the greatest during the first 6 months of wear; (2) there is no difference between 6 and 30 night extended wear; and (3) that wear of hyperoxygen-transmissible lenses would reduce the reported incidence of infection. Subsequent epidemiologic studies have confirmed the first two predictions; however, increased oxygen transmissibility with silicone hydrogel (SiHy) lens wear has not altered the overall incidence of MK. In this review, more recent clinical and basic studies that investigate epithelial alterations and bacterial adhesion to corneal epithelial cells after the wear of SiHy lenses with and without concomitant exposure to chemically preserved multipurpose solutions (MPS) will be examined. The collective results of these studies demonstrate that even in the absence of lens-related hypoxia, MPS induce ocular surface changes during SiHy lens wear that are associated with a pathophysiologic increase in PA adherence and internalization in the corneal epithelium, and therefore, predict a greater risk for PA-MK. In addition, new data supporting an interactive role for inflammation in facilitating PA adherence and internalization in the corneal epithelium will also be discussed.

Research progress in epidemiology of microbial keratitis

Microbial keratitis is one of major causes of vision loss and blindness worldwide today,especially in developing countries in Asia and Africa.Population-based annual incidence of microbial keratitis is 0.36/10000 to 79.9 /104.The epidemiological features and predisposing factors for microbial keratitis varies significantly from country to country,even from region to region within the same country.The progress of research on describing epidemiological characteristics demographic characteristics and predisposing factors of microbial keratitis were reviewed in this paper. Key words: Microbial keratitis; Epidemiology; Predisposing factor

Corneal thinning associated with recurrent microbial keratitis resulting from 7-day extended wear of low Dk hydrogel contact lenses: A case report

Corneal thinning and an increased risk of corneal perforation, resulting from recurrent episodes of microbial keratitis, required a 38-year-old Caucasian female to undergo bilateral corneal grafting. Although strongly advised otherwise, the patient had been a long time user of low oxygen permeability hydrogel contact lenses in a flexible wear regime, with frequent overnight use. Microbial keratitis is a potentially severe contact lens related complication which, if not properly treated, may lead to permanent visual loss. The introduction of silicone-hydrogel materials and daily replacement modalities has not resulted in a significant decrease in the incidence of microbial keratitis, thus suggesting that the condition is mainly dependent on patient hygiene and wearing habits. Non-compliance, which is endemic in contact lens wear, may be combated by increasing patient awareness of the potential risk factors of contact lens misuse. This is accomplished through constant, rigorous information provided by contact lens practitioners.

A Re-evaluation of the Risk of Microbial Keratitis From Overnight Contact Lens Wear Compared With Other Life Risks

In 1995, Myers and Weiss published an article comparing the risk of ulcerative keratitis related to low oxygen permeability (Dk) extended contact lens wear to other life risks. This article updates the risks associated with silicone hydrogel (SH) extended wear contact lens use and some comparative life risks, to provide a current perspective within the hierarchy of life risks. A comparative ratio was defined as the incidence of microbial keratitis in a population of SH extended wear contact lens users divided by the incidence of other disease or occurrence in a given population at risk. The risk of SH lens-related microbial keratitis is about 1.5 to 16 times less risky than certain nonfatal disruptive occurrences in the general population, and about the same as the risk of developing breast cancer. Compared with other ocular conditions, the risk of microbial keratitis with SH lenses is about the same as developing late-stage age-related macular degeneration or retinal detachment after cataract extraction on an annual basis; it is over 200 times greater than developing eye or orbit cancer; it is about 7, 20, or more than 30 times less than proceeding to penetrating keratoplasty in keratoconus, developing nuclear cataract, or experiencing a corneal inflammatory event during low-Dk extended wear, respectively. Although the risk of microbial keratitis with modern day SH contact lens extended wear has not changed since the 1980s, when put in perspective with other life risks, it is a relatively rare occurrence.

MICROBIAL KERATITIS

Objective: To find out the incidence ofmicrobial keratitis in patients with red eyes. Design: randomized prospective study. Period: 07 months ranging from1st Jun 2001 to 31 Dec 2001. Place of study: Eye Department, Military H st ospital, Rawalpindi. Results: Out of 857patients with red eye 32 cases were found to have Microbial Keratitis (3%). Conclusion: Preventive aspects of ocularinfection should be taught to the people, like, proper washing of eyes, wearing of protective glasses. Patients comingwith ophthalmic problems, i.e., red eye, photophobia, irritation and watering to the general practitioner should bereferred as soon as possible to the ophthalmology department.

The Incidence of Microbial Keratitis among Wearers of a 30-Day Silicone Hydrogel Extended-Wear Contact Lens

To estimate the incidence of presumed microbial keratitis with and without loss of visual acuity among wearers of a silicone hydrogel contact lens (Lotrafilcon A, Night & Day, CIBA Vision, Inc., Duluth, GA), recently approved for up to 30 days of continuous wear. Prospective cohort postmarket surveillance study. Contact lens wearers (recruited from 131 practices) who had been prescribed the lens for intended continuous wear of as many as 30 nights. The occurrence of a corneal infiltrate was ascertained through a combination of center report and direct contact with participants at 3 and 12 months. Whenever a corneal infiltrate was suspected, study and treatment medical records were systematically reviewed by an Endpoints Committee using a predetermined classification scheme for corneal infiltration. Cases of presumed microbial keratitis were determined based on the constellation of presenting signs and symptoms and clinical course. The incidence of presumed microbial keratitis with and without loss of visual acuity. A total of 6245 participants were recruited between August 13, 2002 and July 2, 2003. Of these, 4999 subjects (80%) completed 12 months of follow-up, and these participants contributed a total of 5561 person years of lens wearing experience. Approximately 80% of participants routinely wore their lenses continuously for 3 or more weeks. The overall annual rate of presumed microbial keratitis was 18 per 10,000 (95% confidence interval (CI): 8.5-33.1). There were 2 cases of presumed microbial keratitis with loss of visual acuity, an annual rate of 3.6 per 10,000 (95% CI: 0.4-12.9), and an additional 8 cases without loss of visual acuity, an annual rate of 14.4 per 10000 (95% CI: 6.1-28.4). The rate of presumed microbial keratitis was lower for users reporting typical wear of 3 or more weeks than for those wearing the lens for less than a 3-week continuous period (P = 0.02). The incidence of loss of visual acuity due to microbial keratitis among users of the silicone hydrogel contact lens was low. The overall rate of presumed microbial keratitis with the wearing schedule of as many as 30 nights was similar to that previously reported for conventional extended-wear soft lenses worn for fewer consecutive nights.

Extended-wear contact lenses, microbial keratitis, and public health

Extended-wear soft contact lenses (lenses worn continuously for more than 24 h and in many cases for 1–4 weeks) are being relaunched in several countries. This move follows a decade of their restriction by licensing authorities and by contact-lens practitioners because the incidence of microbial keratitis is greater with extended-wear than with daily-wear, soft hydrogel lenses.1,2 Why are extended-wear lenses being revisited and what might be the implications for public health?