Comprehensive Ophthalmology Free Papers - aioseducation

Comprehensive Ophthalmology Free Papers
In Vitro Antibiogram of Streptococcus
Pneumoniae in Ocular Infections
Dr. Priyanka Gogte, Dr. Prashant Garg, Dr. Mukesh Taneja, Dr. Suma N.
The eye may be infected from external sources or through intraocular
invasion of micro-organisms that are carried by the blood stream. 1 External
bacterial infections of the eye are usually localized but may frequently spread
to other tissues. The eyelid and conjunctiva have a normal microbial flora
controlled by its own mechanism and by the host. Modification of this normal
flora contributes to ocular infections such as blepharitis, conjunctivitis,
canaliculitis, orbital cellulitis, endophthalmitis, etc.
Timely institution of appropriate therapy must be initiated to control the
infections and thereby minimize ocular morbidity. If they are not treated
promptly, it may lead to sight threatening condition. 2 For this timely
intervention, it is essential to correctly identify the causative organism with
the help of a thorough microbiological work up and then initiate the therapy
based on the sensitivity pattern of the organism. However to a community
based ophthalmologist without access to a laboratory set up, the information of
common ocular pathogens and the trends in the current antibiotic sensitivity
pattern form the basis of treatment initiation. Also it has been observed
that the causative organisms and their response to antibiotic therapy is not
static and varies according to their geographic location. Thus it is essential to
periodically study these parameters and revise treatment protocols. 3,4
Streptococcus pneumoniae is a Gram positive cocci and is the main cause of
central corneal ulceration among bacterial keratitis in South India. 5 According
to another study from a tertiary care center in South India, Gram positive
organisms accounted for 69.1% of all bacterial isolates with Streptococcus
pneumoniae being one of the 5 most common causative organisms. Therefore,
the purpose of this article is to study the in vitro antibiotic sensitivity pattern
of Streptococcus pneumoniae in ocular infections.
MATERIALS AND METHODS
Retrospective analysis of microbiology records of patients clinically diagnosed
and treated for ocular infections between January 2010 and December 2010
was done. All culture positive samples of significant growth of Streptococcus
pneumoniae were included in the study and the antibiotic susceptibility was
determined using the Kirby-Bauer disc diffusion test.
Corneal scrapings were obtained using standard techniques 6 with a sterile
Bard Parker blade (#15). Collection of vitreous samples was done in a standard
manner. The samples were inoculated directly onto sheep blood agar,
chocolate agar, thioglycolate, and brain heart infusion broth. These media
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