Staphylococcus aureus recovery from cotton towels

Abstract

Background: Staphylococcus aureus is an emerging pathogen afflicting healthy individuals without known risk factors, and methicillin-resistant Staphylococcus aureus has been shown to colonize multiple family members sharing households. Because household items such as towels are often shared by family members, this study investigated whether cotton towel absorbency or washing conditions affect Staphylococcus aureus cell viability or cell retention, and whether the levels may be sufficient for person-to-person transmission. Methodology: Staphylococcus aureus ATCC 25923 was added to a 48 mm2 template area on three cotton towel types (terry, pima, and Egyptian), and subjected to hand washing, without manual wringing, in three conditions (water only, bleach addition, or liquid detergent addition). Serial dilutions plated onto mannitol salt plates quantified bacteria for inoculations, pre- and post-wash water samples, towel surfaces, and hand transfer. Hand transfer of bacteria was determined on towels immediately, one, 24, and 48 hours post inoculation. Results: Bleach (p ≤ .05) was the most effective at reducing bacterial viability on all towel types compared to detergent and water. Although not statistically significant, more Staphylococcus colonies were recovered from higher absorbency towels and from inside directly inoculated template areas. A paired t-test showed a difference between immediate and one-hour CFUs versus 24- and 48-hour recoveries (0.0002) for hand transfers. Conclusions: Cell viability decreased for over 48 hours on towels, but sufficient quantities may remain for colonization. More absorbent towels may harbor more Staphylococci than less absorbent ones, and may serve as a transmission mechanism for the bacterium.