Incidence of contamination of preserved saline solutions during normal use.
OBJECTIVE
To ascertain the incidence of microbial contamination of preserved contact lens saline solutions with normal patient use.


METHODS
Eight different brands of preserved saline were dispensed to 40 patients attending optometric practices in the Sydney area. After specific periods of time (7 to 28 days), the samples were collected and the solution bottle nozzles and contents underwent microbial analysis.


RESULTS
The overall contamination rate was approximately 26% for contents only and 55% for nozzles of preserved saline solutions. This rate remained constant for all periods of use. Coagulase-negative Staphylococci were most frequently isolated. No Acanthamoebae were isolated. Saline preserved with ethylene-diamine-tetraacetic acid (EDTA) in conjunction with sorbic acid showed the highest percentage of sterility.


CONCLUSIONS
The results of this study show that preserved saline became contaminated with gram-positive bacteria. This is in contrast to our previously published paper using unpreserved saline, where contamination was predominantly with gram-negative bacteria. The overall contamination rates with preserved saline were lower than for unpreserved saline.
Sweeney
D F
DF
School of Optometry, and The Cooperative Research Centre for Eye Research and Technology, The University of New South Wales, Sydney, Australia.
Willcox
M D
MD
Sansey
N
N
Leitch
C
C
Harmis
N
N
Wong
R
R
Holden
B A
BA
D018639:Contact Lens Solutions; D003263:Contact Lenses, Hydrophilic; D004203:Disinfection; D004340:Drug Contamination / Q000706:statistics & numerical data; D006094:Gram-Positive Bacteria / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D011310:Preservatives, Pharmaceutical; D012965:Sodium Chloride
D018639:Contact Lens Solutions; D011310:Preservatives, Pharmaceutical; D012965:Sodium Chloride