Aim: To ascertain the effect of elderly in the conjunctival bacteria frequency of patients undergoing cataract extraction.
Methods: A retrospective case series study of 4432 consecutive patients who underwent cataract surgery, without excluding any of them for having pre-existing diseases. Their preoperative conjunctival culture were performed over a 3-year period (1994-1996). Bacteria were grouped in nine categories and patients were divided into seven groups, according to age; comparisons between groups were made by means of the chi(2) test, and the Mantel-Haenszel test to analyse age as a confounder, using SPSS program, version 12.
Results: Patients aged over 74 years accounted for 41.4%; women predominated among this group (61.4%), but not in the patients younger than 75 (47.7%); In the whole sample women accounted for 53.4%. Patients aged 75-96 years had a greater frequency of: Corynebacteria, Staphylococcus aureus, Streptococcus sp. (except Streptococcus pneumoniae), Gram-negative cocci and Gram-negative rods (except Haemophilus sp.) and 'other bacteria' categories than those aged 3-74 years. Different bacteria frequency in both sexes produced a confounding effect in the comparison between age-groups. Men had more Staphylococci coagulase (-), S. pneumoniae and Gram-negative rods than women.
Conclusions: Elderly patients awaiting cataract surgery had more conjunctival bacteria than those younger than 75 years, except Staphylococcus coagulase negative, S. pneumoniae and Haemophilus sp. At any age, men had more bacteria than women. These increments of frequencies could increase the risk of intraocular surgery contamination.