Negligible influence of limescale deposits on faucet aerators on measured microorganism loads.

Introduction: The study was conducted to assess the effects of limescale deposits on faucet aerators on the qualitative and quantitative detection of microorganisms from swabbing and first jet water samples. Methods: Limescale deposits on faucet aerators were categorized into three groups: not / slightly calcified, moderately calcified and heavily calcified. Colonization was assessed by isolating microorganisms from standardized swabbing and water samples. Microorganisms isolated from the aerators were compared with clinical isolates from the same year. Results: Regardless of the degree of calcification on the faucet aerators, similar numbers and types of microorganisms were found. Except for Staphylococcus epidermidis and the rare occurrence of Staphylococcus aureus and Nacaseomyces glabratus on the aerators, there were no matches between the microorganisms isolated from the aerators and the top ten clinical isolates. Microorganisms frequently isolated from aerators, such as Sphingomonas paucimobilis, were extremely rare in clinical samples. No differences in species were observed based on the degree of calcification of the aerators. Conclusions: The study did not demonstrate a significant effect of the degree of calcification on the colonization of aerators. Although calcification of aerators as a risk factor for increased microbial transmission cannot be entirely dismissed, its importance appears to be secondary.