Contamination of diagnostic ophthalmic solutions in primary eye care settings

Pharmaceutical agents and irrigating solutions are widely used in both optometric and ophthalmologic practices. Contamination of these containers or solutions could possibly pose some risk of infection to a patient. We set out to investigate the possible contamination of a representative sample of these containers in small office practices. Representative bottles of two diagnostic pharmaceutical agents and an irrigating solution were obtained from primary care optometric and ophthalmologic practices in the San Francisco-Oakland Bay area. These bottles were tested to investigate the rate of contamination and to identify the types of microorganisms in the contaminated solutions. Sixty total samples (proparacaine, tropicamide, and an irrigating solution) were randomly cultured, and 11.7% of the samples showed contamination. Pseudomonas cepacia, Staphylococcus epidermidis, Pseudomonas putida, and Streptococcus species were the predominant organisms isolated from the contaminated bottles. In addition, 17 of the original 60 containers were further cultured for investigation of the dried residue particles around the threads of the containers. Of these 17 containers, 13 (76.5%) tested positive for Staphylococcus and Micrococcus species.