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Influence of possible disinfectant transfer on Staphylococcus aureus plate counts after agar contact sampling
Abstract:
Asbestos-vinyl tile floor panels were mopped with three types of chemical disinfectant product, as well as after contact, with the untreated control panel were prepared according to the manufacturer's label instructions. Similar floor panels were inoculated artificially with Staphylococcus aureus. RODAC (replicate organism detection and counting) surface sampling plates were pressed to the disinfectant-treated panels or to the untreated control panel and then immediately pressed to sampling sites on the artificially inoculated floor panels. Plate counts were determined after contact with panels treated with each type of disinfectant, product, as well as after contact with the untreated control panel. Results indicate that disinfectant residues on environmental surfaces do not alter the average plate counts obtained by RODAC samplings.
Insights
Disinfectant residues on surfaces do not affect bacterial counts when using RODAC (replicate organism detection and counting) sampling plates. This finding is crucial for accurate environmental surface hygiene assessments.
Area of Science:
- Microbiology
- Environmental Health
- Infection Control
Background:
- Accurate assessment of surface contamination is vital for infection control.
- Replicate Organism Detection and Counting (RODAC) is a common method for surface sampling.
- The potential impact of disinfectant residues on RODAC sampling accuracy is not well understood.
Purpose of the Study:
- To determine if disinfectant residues on environmental surfaces affect bacterial counts obtained by RODAC sampling.
- To evaluate the reliability of RODAC sampling in the presence of common disinfectant residues.
Main Methods:
- Asbestos-vinyl tile floor panels were treated with three chemical disinfectants or left untreated (control).
- Panels were artificially inoculated with Staphylococcus aureus.
- RODAC plates were used to sample both treated and untreated panels, and then transferred to inoculated surfaces.
- Bacterial colony counts were determined after incubation.
Main Results:
- Average plate counts from RODAC samplings were consistent across disinfectant-treated and untreated control panels.
- Disinfectant residues did not significantly alter the number of bacteria recovered by RODAC sampling.
- The presence of disinfectant residues did not interfere with the detection of Staphylococcus aureus.
Conclusions:
- Disinfectant residues on environmental surfaces do not interfere with the accuracy of bacterial quantification using RODAC surface sampling plates.
- RODAC sampling remains a reliable method for assessing surface contamination even after disinfection.
- These findings support the continued use of RODAC sampling for environmental hygiene monitoring in healthcare and other settings.