Microbiologic analysis of bottled water: is it safe for use with contact lenses?
OBJECTIVE
To analyze commercially available bottled water as a possible source of microbial contamination of contact lenses.


METHODS
Two different lots of 23 brands of noncarbonated bottled water were tested for coliforms, total bacteria, fungi, and free-living amebae. A sample consisted of three separate 100-ml aliquots from one lot of each brand (46 samples). Aliquots were vacuum-filtered using a 0.45-microm Nalgene analytical filter unit, and the membrane filter was placed on a filter pad in a Petri dish containing test medium. Plates were examined under a stereomicroscope, and the number of colony-forming units (CFUs) was calculated for each sample. To test for the presence of free-living amebae, three aliquots totaling approximately 3800 ml were concentrated using 8-microm filters, and the filters were placed on non-nutrient agar with live Enterobacter aerogenes. To assess the possibility of contaminating contact lenses, etafilcon lenses were rinsed in 2-ml aliquots of four brands of bottled water and then cultured.


RESULTS
Seventeen (37%) of 46 samples, representing 11 (48%) of 23 brands, contained viable micro-organisms. Bacteria, including coliforms, were recovered from 12 samples of 8 brands. Yeasts or molds were recovered from seven samples of five brands. Free-living amebae were isolated from two samples, and fresh-water algae were found in both samples of one brand. Nine (20%) of 46 samples, representing 7 (30%) of the 23 brands, had more than 500 CFUs per ml or contained coliforms. Sterile contact lenses became contaminated when exposed for 1 minute to two of four brands of water from which micro-organisms were recovered.


CONCLUSIONS
Some bottled waters contain high numbers of potential ocular pathogens. Bottled water is not safe for routine use with contact lenses.
Penland
R L
RL
Sid W. Richardson Ocular Microbiology Laboratory, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.
Wilhelmus
K R
KR
D000656:Amoeba / Q000254:growth & development / Q000302:isolation & purification*; D000818:Animals; D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D018639:Contact Lens Solutions; D003261:Contact Lenses / Q000382:microbiology; D005658:Fungi / Q000254:growth & development / Q000302:isolation & purification*; D012449:Safety; D014867:Water / Q000469:parasitology*; D014871:Water Microbiology
D018639:Contact Lens Solutions; D014867:Water