Bacterial flora in relation to cataract extraction. III. Postoperative flora.

The conjunctival flora of 499 patients operated for cataract was studied on the 4th and 7th postoperative days and compared with the flora examined previously on admission to the hospital and at the time of surgery (Fahmy et al. 1975b, c). Antibiotics had been administered approximately 18 hours before operation, at the conclusion of surgery, and then on the 4th postoperative day after the cultures had been taken. After a significant fall in incidence, including all kinds of bacteria at the time of surgery (Fahmy et al. 1975c), Staphylococcus albus showed an increase in incidence on the 4th postoperative day to the level found on admission. Corynebacteria and gram-negative bacilli likewise showed increasing incidence but not to the level of admission. The incidence of Staphylococcus aureus and streptococci remained unchanged. On the 7th postoperative day, S. aureus showed a fall in incidence while other bacteria had largely the same incidence as that of the 4th postoperative day. The origin of S. aureus isolated postoperatively from the conjunctiva was studied, and showed that the great majority of strains were similar to those found on the patient's own conjunctiva preoperatively. In a few instances, S. aureus could be traced to the patient's own nose or to the noses of some of the nurses. The air of the wards, eye drops or ophthalmic ointments used in the treatment of the patients apparently did not play any role as a source of S. aureus infection. Cultures obtained on the 4th postoperative day showed only a minor relationship to the flora of the wound site observed at the conclusion of surgery.