|Year : 2017 | Volume
| Issue : 3 | Page : 130-133
Epidemiologic characteristics, predisposing risk factors, and etiologic diagnosis of corneal ulceration in Belagavi
Rekha Mudhol, Linda Maria Genoveva De Piedade Sequeira
Department of Ophthalmology, JNMC, Belagavi, Karnataka, India
|Date of Web Publication||14-Feb-2018|
Department of Ophthalmology, JNMC, Belagavi, Karnataka
Source of Support: None, Conflict of Interest: None
Purpose: To evaluate the factors predisposing to the onset of corneal ulceration and to identify the specific causative organisms. Materials and Methods: This was a 1-year cross-sectional study. Fifty patients with infectious keratitis were included in the study. A detailed history with documenting his/her sociodemographic information, presenting complaints, previous treatment, predisposing ocular conditions, and associated risk factors was noted, followed by slit lamp biomicroscopy and scraping for staining and culture analysis. Results: Bacterial infections were noted more commonly (28%) than fungal infections (12%) with Streptococcus pneumoniae and Staphylococcus aureus accounting for the majority of bacterial ulcers (68.75%), and Fusarium species and Aspergillus species were equally (50% each) responsible for most of the fungal infections. The most common predisposing risk factor is ocular trauma (74%). Conclusion: Comprehensive surveys are necessary to assess the specific epidemiological characteristics of corneal ulceration, which are unique for each region and population. It in turn helps to define the magnitude of the problem and design efficient public health programs for its management.
Keywords: Causative agents for corneal ulcers, infectious keratitis, risk factors for infectious keratitis
|How to cite this article:|
Mudhol R, De Piedade Sequeira LM. Epidemiologic characteristics, predisposing risk factors, and etiologic diagnosis of corneal ulceration in Belagavi. J Sci Soc 2017;44:130-3
|How to cite this URL:|
Mudhol R, De Piedade Sequeira LM. Epidemiologic characteristics, predisposing risk factors, and etiologic diagnosis of corneal ulceration in Belagavi. J Sci Soc [serial online] 2017 [cited 2018 Nov 17];44:130-3. Available from: http://www.jscisociety.com/text.asp?2017/44/3/130/225509
| Introduction|| |
Corneal ulceration is a major preventable cause of monocular blindness in developing countries. Several investigators have reported the prevalence of bacterial and fungal pathogens isolated from ulcerated corneas;,,,,, however, there are few population-based studies demonstrating the true incidence of microbial keratitis in developing countries. Rational treatment involves identifying the causative agent and institution of specific antimicrobial chemotherapy. This demands clinical suspicion of a microbial cause for keratitis, knowledge of the likely agents in a particular community, reliable microbiological investigations, and the availability of effective antibiotics. Microbial keratitis varies significantly from country to country and even from region to region in terms of the epidemiological characteristics, demography, predisposing factors, clinical and microbiological profile., In order to develop a comprehensive strategy for the diagnosis, treatment, and ultimately for the prevention of corneal infection, the etiological factors predisposing to the ulceration and pathogenic organisms, which are responsible, must be determined.
| Materials and Methods|| |
The study was conducted in a medical college in South India. Fifty patients with infections such as corneal ulcer/ulcers attending at the outpatient department were included in this study. The exclusion criteria included typical viral ulcers, sterile neurotrophic ulcers, any ulcers associated with autoimmune condition, Mooren's ulcer, corneal dystrophies, and degeneration.
A standardized form was filled out by each patient documenting his/her sociodemographic information as well as clinical information including duration of symptoms, previous treatment, predisposing ocular conditions, and associated risk factors.
Every patient was examined at the biomicroscopy, and the size of epithelial defect was recorded in mm in a standardized form. Scraping was performed after instillation of 4% lignocaine. Material obtained by scraping the leading edge and base of each ulcer was inoculated directly into blood agar, chocolate agar, and sabouraud dextrose agar (SDA). And onto three separate glass slides, one for Gram-stain, one for Giemsa stain, and one for potassium hydroxide (KOH) wet mount.
If the KOH smear was found to be positive for amoebic cysts, further corneal scraping was performed and the material was inoculated into nonnutrient agar overlaid with Escherichia More Details coli in an attempt to isolate Acanthamoeba species.
| Results|| |
Most of the patients included were between 15 and 45 years. Ninety percent of the cases in this study were from poor socioeconomic status [Table 1]. The majority were farmers or hired agricultural workers, 35 (70%) were usually working in rice or sugarcane fields in village followed by 7 (14%) tradesmen/p rofessional, 5 (30%) homemakers, and 3 (6%) children. Only 6.6% of patients sought treatment within 2 days, while 70% sought treatment within the 2 weeks.
Only 10% of cases approached an ophthalmologist before visiting our hospital, 34% approached general practitioners while nearly 20% approached traditional eye doctors in their villages. However, 36% of cases came directly to this hospital without availing any prior treatment.
Traditional eye medicine (TEM) was used by 28% of cases while 62% of the cases used over-the-counter topical antibiotics as shown in [Table 2]. Antifungal treatment was not given to any of the cases except one along with topical antibiotics. One of the patients was treated with topical steroids which resulted in poor visual outcome, and one patient received TEM along with antibiotics.
Out of 50 corneal ulcer patients, 41 had definite risk factors; of which, ocular trauma was the most common risk factor accounting for 74%, of which 24 (64.87%) had trauma with vegetable matter and 13 (35.13%) had trauma with dust as shown in [Table 3].
Sixty-nine percent of the patients presented with central located ulcers, 18% with peripheral ulcers, and 12% with paracentral ulcers, respectively. The ulcers were further graded based on the progression, area, depth, perforation, and scleral suppuration. When 3 criteria were met, they were included in the severe disease category. We noted that 90% cases in this study belong to the nonsevere category.
Out of 50 cases, Gram's stain was positive in 14 cases, in that 8 were positive for Gram-positive cocci and 6 were positive for Gram-negative bacilli. None of the Gram stain smears showed fungal elements. In 11 patients, KOH was positive for fungal filaments.
Blood and chocolate agar showed growth of bacterial organisms in 19 patients and SDA showed growth of fungal organisms in 6 patients. Out of the 6 fungal growths, 3 cases showed additional growth on blood and chocolate agar. Microbiological growth patterns in cultures from 50 consecutive corneal ulcers showed bacterial etiology in 28% and fungal etiology in 12%.
A total of 16 bacterial organisms were cultured from 14 corneal ulcers. Of the 16 isolated, 11 (68.75%) were Gram positive and 5 (31.25%) were Gram negative. Streptococcus pneumoniae and Staphylococcus aureus were the most common organisms as shown in [Table 4].
A total of 6 fungal organisms were cultured from 6 corneal ulcers. Of the 6 cases, Fusarium species accounted 3 (50%) and Aspergillus species accounted 3 (50%) cases as shown in [Table 5]. None of the cultures were positive for Acanthamoeba.
| Discussion|| |
Corneal ulceration is a major preventable cause of monocular blindness in developing countries. A recent report in the cause of blindness worldwide consistently lists corneal scarring second only to cataract as a major etiology of blindness and visual disability in many of the developing counties including India.
In studies conducted by Gonzales et al. and Srinivasan et al., it was documented that the annual incidence of corneal ulcerations was estimated to be 11.3/10,000 persons or at least 10 times more frequent than the incidence of similar infections in an age-adjusted and a sex-adjusted population in the USA.,
In our study, majority of the ulcer patients were agricultural workers, homemakers, or laborers (80%), an occupation profile similar to Nepal (72%) and South India Madurai (78.8%), but in marked contrast with Ghana where only 16.1% of the patients were involved in agriculture activity.
It is of interest that over 60% of the patients in the study presented for examination during the 1st week of their illness. In contrast, in a study conducted in Paraguay by Florentina et al., only one of every four patients presented in the 1st week of illness. However, before their initial examination, 62% of all patients consulted a health-care provider of some kind, 18% of whom were seen by a quack (TEM). General practitioner examined 34% and ophthalmologist examined 10%.
Due to the easy over-the-counter availability of drugs, it was noticed that 62% of the patients had started on topical medication before their initial examination. Nine of these patients (28%) were using some kind of traditional or herbal topical treatment. In a study conducted by Courtright in rural Malawi, it was noted that a considerable number of patients used TEMs in the form of application of plant products directly into the eye, intensive face cleaning, and steam baths among patients with corneal diseases.
Superficial corneal trauma during agricultural work often leads to rapidly progressing corneal ulceration and visual loss., In South India, paddy and rice stalk in the field was the most common cause of superficial corneal trauma. However, in this study, the most common cause of superficial corneal trauma was rice husk followed by other causes such as wooden stick injury.
In the present study, the Gram stain report correlated with culture report in 80% of the cases whereas in the study conducted by Galentine  and Williams, it was found to be about 63%. Therefore, the Gram stain report can be used as a guide for initial therapy that can be modified later according to the culture reports. KOH stain is particularly important for the early initiations of antifungal treatment in mycotic keratitis. In a study conducted by Vajpajee RB in Delhi, it was observed that KOH sensitivity was found to be 94%.
In this study, 50% of the corneal scrapings were culture positive. This is similar to the reports in Ghana (57.3%), South India (68.4%), and Uttarakhand (68.4%). Among these, 19 (38%) cases were positive for bacteria and 6 for fungus (12%). This is in contrast to the reports in South India as reported by Leck et al. and Bharathi et al. where 10 (44.1%) of the cases were positive for fungal pathogens.
In a study conducted in Africa, Carmichael studied 283 corneal ulcers and concluded that central bacterial ulcers are the most common morphological presentation of corneal ulcers, the most common organism isolated in this group being S. pneumoniae. Similarly, in our study, 69% of the patients presented with central located ulcers, 18% with peripheral ulcers, and 12% with paracentral ulcers, respectively.
Studies conducted by Derek et al. suggest that Staphylococcus epidermidis (31.1%), filamentous fungi (25.7%), Corynebacterium species (16.3%), S. pneumoniae (13.5%), and Pseudomonas aeruginosa (13.5%) are the leading etiological microbes of microbial keratitis in the elderly. However, in our study, S. pneumoniae (31%) and S. aureus (31%) were the most common organisms isolated followed by pseudomonas and other Enterobacteriaceae.
In the developing world, S. pneumoniae should always be considered as the most likely cause of bacterial corneal ulceration until proved otherwise, even though pseudomonas species has been identified as a frequent cause of corneal ulceration in some developing countries.,,
In a study conducted by Geeta et al. in Hyderabad, cultures were found to be positive for Aspergillus in 55 (42%) and Fusarium in 42 (32%). Similarly, in our study, of the 6 cases positive for fungal growth, Fusarium species accounted 3 (50%) and Aspergillus species accounted 3 (50%) of the cases.
| Conclusion|| |
Corneal ulceration is a common problem in this part of Karnataka and most often occurs after a superficial corneal injury with organic material. Bacterial infections occur more commonly than fungal infections with S. pneumoniae and S. aureus accounting for the majority of bacterial ulcers while Fusarium species and Aspergillus species were responsible for most of the fungal infections.
Comprehensive surveys such as this study are necessary to assess the specific epidemiological characteristics of corneal ulceration, which are unique for each region and population and are also necessary to define the magnitude of the problem in society, to design an efficient public health program for rapid referral, diagnosis, treatment, and to prevent corneal ulceration in the population at risk, especially in the developing nations.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]