Ocular flora of patients with AIDS compared with those of HIV-negative patients.

PURPOSE: To determine whether there are quantitative or qualitative differences in the ocular flora of patients with acquired immunodeficiency syndrome (AIDS) compared with human immunodeficiency virus (HIV)-negative patients. METHODS: Forty patients with AIDS and 42 HIV-negative controls were sex and age matched. All subjects had a detailed anterior segment examination, including Schirmer's test, rose bengal staining, and quantitative cultures of the conjunctiva and lids. Statistical evaluation of the relation between AIDS, keratoconjunctivitis sicca (KCS), and ocular flora was performed. RESULTS: No differences were observed in the types or numbers of organisms isolated from the conjunctiva or lids of patients with AIDS and HIV-negative subjects. Ocular flora was not influenced by use of systemic antibiotics, level of immunosuppression as measured by CD4 lymphocyte counts, KCS, or other ocular-surface disease. One AIDS patient was colonized by large numbers of Haemophilus influenzae OU with minimal clinical signs of inflammation or infection. CONCLUSION: There do not appear to be any differences in the ocular flora of HIV-negative patients and patients with AIDS. Presence of KCS and level of immunosuppression do not appear to affect the ocular flora in patients with AIDS.

Antibiotic supplementation of intraocular irrigating solutions. An in vitro model of antibacterial action.

PURPOSE: The addition of antibiotics to infusion solutions for cataract surgery is becoming increasingly popular. The authors developed an in vitro model to evaluate antibacterial effects of this use of antibiotics. METHODS: Clinical isolates and/or reference strains of the following organisms were examined: coagulase-negative Staphylococcus spp, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus viridans, Streptococcus spp, Enterococcus spp, Proprionibacterium acnes, Moraxella nonliquifaciens, and Pseudomonas aeruginosa. Standardized suspensions of each organism were incubated with a control solution (Balanced Salt Solution) or Balanced Salt Solution containing the following antibiotics: vancomycin (20 micrograms/ml) or gentamicin (8 micrograms/ml) or gentamicin and vancomycin combined (8 and 20 micrograms/ml, respectively). Suspensions were incubated for 30, 60, and 120 minutes at room temperature. Samples were centrifuged, and the organisms were washed with Balanced Salt Solution before quantitative culturing. Each organism also was incubated for 48 hours in Mueller-Hinton broth with the same antibiotic concentrations. RESULTS: Most of the organisms were not affected by exposure to the antibiotics for up to 140 minutes. P. aeruginosa and M. nonliquifaciens were exceptions, decreasing in colony numbers even with 30 minutes of exposure. Several Staphylococcus spp yielded variable results. All organisms demonstrated nearly complete inhibition of growth when exposed for an extended time to the appropriate antibiotic in broth. CONCLUSIONS: Exposure to antibiotics for a short period of time, such as during intraocular surgery, generally has no effect on organisms commonly responsible for endophthalmitis. The use of antibiotics in this manner should be critically reassessed until further study.