ABSTRACT

CORRESPONDING AUTHOR:
Dr. N. Padmaja,
Associate Professor,
Department of Microbiology,
KIMS, Amalapuram.
E-mail: masalapadmaja@gmail.com

ABSTRACT: Corneal ulcers are the common cause of corneal blindness. Of the corneal ulcers, majority of the cases are because of the fungal etiology. The present study is aimed to identify the pathogenic organisms responsible for corneal infections. Majority of the cases are secondary to trauma. Of the fungal cases, Aspergillus is found to be the predominant fungus affecting corneal ulcers, followed by bacteria affecting the corneal ulcers.

KEYWORDS: Corneal ulcers, fungal etiology, aspergillus, corneal blindness, trauma.

AIM: To study the microbial aspect of corneal ulcers.

MATERIALS & METHODS: This study was conducted in the Dept. of MICROBIOLOGY, KIMS, Amalapuram between October 2012–April 2013. 50 patients with corneal ulcers, who attend Ophthalmology Dept. at KIMS, Amalapuram are included in the study. After clinical evaluation, corneal scrapings were collected and subjected to microscopy Gram’s smear & KOH mount and cultures on SDA, Mac Conkey and BA as per standard protocols in all patients.¹

RESULTS: Out of 50 patients, 30 (60%) were males and 20 (40%) were females. Maximum number of cases 28(56%) were seen in the age of group of 30 – 50 yrs. Majority of the patients were from rural areas 45(90%) and most of them were farmers 30(60%). Most of the cases were reported during harvest season i. e around November to January. Most cases have a history of trauma 38 cases (76%), exposure Keratitis 7(14%) and Corneal xerosis 5(10%). On Grams staining, 3 cases (6%) showed positivity for the presence of gram positive bacteria & 2 cases (4%) for gram negative bacteria. Of the KOH mounts, 25 cases (50%) were positive for fungal elements.

Out of 50(100%) cases, 30(60%) were positive for culture. Out of which 25(50%) cases were culture positive for fungal elements and 5(10%) cases were culture positive for bacteria. 20(40%) cases were culture negative and 2(4%) cases showed mixed growth of the fungal isolates, Aspergillus – 20(40%) was the commonest isolate, followed by Fusarium - 3(6%) and Pencillium 2(4%). Of the bacterial isolates, Staphylococcus aureus was isolated in 3 cases (6%) followed by Pseudomonas aeruginosa 2(4%).²

DISCUSSION: Blindness is the most morbid condition. Corneal blindness amounts for 20-30% of all blindness in the developing countries of the world, the leading cause of which is ulcerative Keratitis of fungal origin.³ The integrity and transparency of cornea are absolutely essential for the transmissions of light rays into the eye. Because of its external location, cornea is vulnerable to various insults and it can ultimately lead to loss of sight. Our region, Amalapuram, is agriculture rich and is the main occupation of the people in this part of the country. Fungal Keratitis is commonly seen in these agricultural workers. There is regional variation in isolation of microbes in corneal ulcer, ^{3- 5} in this study.

Staphylococcus aureus and Aspergillus spp are the most common microbes isolated. In some studies fusarium was found to be most common species.⁵

KOH wet mount is of great diagnostic value in the management of Fungal Keratitis and is recommended in all clinics for establishing timely treatment.

CONCLUSION: Ocular trauma and accidental spillage of vegetative material in to the eye major risk to the infection to cornea. Proper education and prompt treatment can prevent the blindness.^{6, 7}

BIBLIOGRAPHY:

1. Ananthanarayana R, Panikar CKJ. Text book of Microbiology: 9^th edition. Medical Mycology: Occulomylosis – 625, 2005.
2. Bharathi MJ. Ramakrishnan R, Vasu S, Meenakshi R, Palniappan R. Aetiological diagnosis of microbial Keratitis in South India: A study of 1618 cases. Indian J Med Microbiol 2002; 20: 19-24.
3. Asha Pichare, Neeta Patwardhan, AS Damle, AB Deshmukh. Bacteriological and Mycological study of corneal ulcers in and around Aurangabad. Indian Journal of Pathology and Microbiology 2004: 47 (2): 284-286.
4. Bharathi MJ, Ramakrishna R, Vasu S, Meenakshi R. Epidemiology of Bacterial Keratitis at a Referral Centre in South India. Indian Journal of Medical Microbiology. 21: 4, 239 to 245. Oct. 2003.
5. Deshpande S.D, KoppiKar G.V. A study of mycotic keratitis in Mumbai. Indian Journal of Pathology and Microbiology. 42: 1. 81 to 87, Jan 1999.
6. Gilbert Smolin, Richard. A. Thoft. The cornea 3^rd edition. Lippin Cott Williams & WilKins Publications. Chapters 5 & 7, Bacterial and Fungal Keratitis. 115 & 230 – 1994.
7. Jagadish Chander. Text book of Medical Mycology. Mehta Publications. 2^nd edition. Chapter 28 – Oculomycoses – 310 to 319. 2002.