Surgical Infection Research Group, Faculty of Medicine and Health Sciences, Macquarie University, New South Wales, Australia.
Department of Statistics, Macquarie University, New South Wales, Australia.
J Hosp Infect. 2018 Nov;100(3):e85-e90. doi: 10.1016/j.jhin.2018.06.021. Epub 2018 Jun 28.
Dry surface biofilms (DSBs) persist for extended periods in hospital, and may play a significant role in transmission of healthcare-associated infections.
To determine whether DSBs may be transferred from hospital surfaces to healthcare workers' hands.
Twelve-day Staphylococcus aureus DSB was grown on polycarbonate and glass coupons in a CDC Biofilm Reactor. A total of 1.8 × 10 and 8.8 × 10 bacteria grew on the polycarbonate and glass coupons respectively. Transmission was tested by lifting the coupon with forefinger and thumb of ungloved hands to a height of 30 cm, then touching horse blood agar (HBA) plates 19 sequential times. Transferred bacterial number was determined by colony-forming units. The effect of DSB wetting on biofilm transfer was tested with 5% neutral detergent treatment for 5 s.
Between 5.5 and 6.6% of the DSB bacteria were transferred to hands with one touch and ∼20% were then transferred to HBA with one touch, giving an overall transfer rate of 1.26% and 1.04% for polycarbonate and glass coupons, respectively. Detergent treatment had little effect on bacterial removal from coupons, but, for biofilm grown on polycarbonate, significantly increased transferral to HBA (P < 0.001) to 5.2%. Large numbers of bacteria were transferred by bare hands to multiple fomites. One-third of polycarbonate coupons transferred >1000 colonies during the first five sequential touches. Sufficient bacteria to cause infection were transmitted up to 19 times following one touch of the DSB.
DSB bacteria are transferred by hands from one fomite to multiple fomites, suggesting that DSB may serve as a persistent environmental source of pathogens.
干燥表面生物膜（DSB）在医院中会持续存在很长时间，并且可能在医院获得性感染的传播中起重要作用。
确定 DSB 是否可以从医院表面转移到医护人员的手上。
在 CDC 生物膜反应器中，在聚碳酸酯和玻璃小片中培养了 12 天的金黄色葡萄球菌 DSB。聚碳酸酯和玻璃小片中分别生长了 1.8×10 和 8.8×10 个细菌。通过用未戴手套的手的食指和拇指提起小纸片，使其升高至 30cm 的高度，然后用手指触摸马血琼脂（HBA）平板 19 次来进行传输测试。通过平板上的菌落形成单位（CFU）来确定转移的细菌数量。通过用 5%中性洗涤剂处理 5s 来测试 DSB 润湿对生物膜转移的影响。
一次触摸可将 DSB 细菌中的 5.5%至 6.6%转移到手上，而其中约 20%随后可通过一次触摸转移到 HBA 平板上，因此聚碳酸酯和玻璃小片中的总转移率分别为 1.26%和 1.04%。洗涤剂处理对从小纸片上清除细菌几乎没有影响，但是对于在聚碳酸酯上生长的生物膜，它会显著增加对 HBA 的转移率（P<0.001）至 5.2%。大量细菌通过裸手转移到多个载体上。在最初的五次连续触摸中，有三分之一的聚碳酸酯小纸片转移了超过 1000 个菌落。在一次触摸 DSB 后，可传递足以引起感染的大量细菌达 19 次。
DSB 细菌通过手从一个载体转移到多个载体，这表明 DSB 可能是病原体的持续环境来源。
