Bacteriology of the healthy conjunctiva.

Abstract

THE normal bacterial flora of the mucous membranes of the human body have been described for many years and the nature of the common inhabitants is well established; the bacteriological findings in the healthy conjunctiva have been critically surveyed by Duke-Elder (1938). These latter results were obtained in the decades before the use of modern chemotherapeutic drugs for ocular infections became widespread, and it is important to know in what way, if any, such treatment is influencing the commensal organisms of the eye. It has been postulated that the selection pressure due to the use of antibiotics will favour the replacement of bacteria sensitive to these drugs, by strains or mutants which have become, or are, drug-resistant. Recent reports by Gibson (1951) and Barfoed (1953) suggest that these changes may be occurring. In order to determine whether similar changes were happening in London, a survey of the bacterial flora found in 5,000 persons who were admitted for clean surgical procedures was undertaken. From such data it was hoped to determine which single antibiotic, or combination of antibiotics, was most likely to be of use in the pre-operative sterilization of the conjunctiva. Since most of the cultures reported below were taken during the years 1950-51, they do not reflect the effect of the aureomycin-chloramphenicol group which was not in widespread ophthalmic use at that time. Acquired antibiotic resistance was, therefore, restricted to penicillin, streptomycin, and the sulphonamides.