Durable and regenerable antibacterial fabrics were prepared by using an innovative chemical technology employing a precursor biocidal agent, dimethylol dimethylhydantoin (DMDMH), in a chemical finishing process. The method resulted in significant add-on rates of hydantoin groups on cellulose and established a durable antimicrobial functionality, once the grafted heterocyclic compounds were chlorinated by diluted chlorine bleaching. Both cotton fabrics and polyester/ cotton fabrics exposed to treatment baths containing from 2 to 10% of DMDMH acquired a powerful inactivating capacity against a wide range of food-borne and water-borne infectious disease agents. The biocidal functions are regenerable by regular laundry exposure to chlorine bleach and can withstand over 50 standard machine washes without appreciable deterioration. In addition to their powerful antimicrobial efficacy, the fabrics exhibited improved wrinkle resistance and maintained appropriate mechanical properties, making them ideal for medical and hygienic textile applications. In this article we report the results from biocidal tests and durability evaluations and provide data characterizing physical attributes of the treated fabrics.

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Water samples collected from 28 dental facilities in six U.S. states were examined for the presence of Legionella pneumophila and other Legionella spp. by the PCR-gene probe, fluorescent-antibody microscopic, and viable-plate-count detection methods. The PCR and fluorescent-antibody detection methods, which detect both viable and viable nonculturable Legionella spp., gave higher counts and rates of detection than the plate count method. By the PCR-gene probe detection method, Legionella spp. were detected in 68% of the dental-unit water samples and L. pneumophila was detected in 8%. Concentrations of Legionella spp. in dental-unit water reached 1,000 organisms per ml or more in 36% of the samples, and 19% of the samples were in the category of 10,000/ml or above. L. pneumophila, when present in dental-unit water, never reached concentrations of 1,000/ml or more. Microscopic examination with fluorescent-antibody staining indicated that the contamination was in the dental-unit water lines rather than in the handpieces. Legionella spp. were present in 61% of potable water samples collected for comparative analysis from domestic and institutional faucets and drinking fountains; this percentage was not significantly different from the rate of detection of Legionella spp. in dental-unit water. However, in only 4% of the potable water samples did Legionella spp. reach concentrations of 1,000 organisms per ml, and none was in the 10,000 organisms-per-ml category, and so health-threatening levels of Legionella spp. in potable water were significantly lower than in dental-unit water. L. pneumophila was found in 2% of the potable water samples, but only at the lowest detectable level. The results demonstrate that high concentrations of Legionella spp. frequently develop in dental-unit water lines. They suggest that, although L. pneumophila is not the dominant component in dental-unit water, heavy exposure to species of Legionella should be investigated as a potential health risk for dental personnel and their immunocompromised patients.