Transfer from other surfaces

Studies using drying times ranging from a few minutes to 48 hours, have demonstrated that longer drying periods can result in lower transfer rates (Annand et al., 2007; Hedin et al., 2010; Lopez et al., 2013;

Rusin et al., 2002; Scott & Bloomfield, 1990). Whilst allowing the bacterial suspension to dry in the biological safety cabinet prior to testing may have negatively impacted the survival of the bacteria in this study, due to evaporation and desiccation, the drying of contaminants does occur during the everyday use of MCDs. Indeed, several important pathogens, including Clostridium difficile, MRSA, VRE, Acinetobacter baumannii, and Pseudomonas aeruginosa, have the ability to survive on dry surfaces (Otter et al., 2011).

The transfer potential from patients, and from the surfaces of objects other than MCDs, must also be acknowledged. This may lead to the contamination of hands which in turn may transfer onto the MCD, or may directly contaminate the device if it is placed on the surface. Scott & Bloomfield, (1990) concluded that when contaminated surfaces came into even brief contact with fingers or inanimate objects, there were sufficient numbers of organisms transferred to be cultured and enumerated. Boyce et al., (1997) demonstrated that nurses performing activities in the rooms of patients with MRSA, with no direct patient contact, contaminated their gloves with the pathogen. There is also evidence of healthcare workers contaminating their hands with MRSA, VRE, Clostridium difficile, from touching both patients and the inanimate objects in patients’ rooms; at times, these bacteria were then transferred to other surfaces through touch (Duckro et al., 2005; French et al., 2004; Guerrero et al., 2012; Stiefel et al., 2011).

The handling of smaller MCDs is not dissimilar to the action of handshaking, which has been shown to transfer 30% of Clostridium difficile spores to the hands of recipients, even after contaminated hands were cleaned with an alcohol-based hand rub (Jabbar et al., 2010). Similar transfer efficiency of 32% was noted by Knobben et al., (2007) for moist glove-to-glove mean transfer for multiple bacterial strains (Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium acnes). For Staphylococcus aureus specifically, moist transfer efficiency from glove to glove was 26%. Lingaas &

Fagernes, (2009) also investigated transfer during the shaking of both gloved and un-gloved hands by a donor hand contaminated with Escherischia coli. They identified that transfer occurred in both cases, but there was significantly higher transfer onto the gloved hand, than the bare hand. In contrast, Greene et al., (2015) identified that for Acinetobacter baumannii, the use of latex gloves significantly reduced both the fomite-to-finger and finger-to-fomite transfer efficiencies, compared with no glove use.

Due to the fact that MCDs are kept in pockets and bags, the transfer capabilities of fabrics must also be considered. Mackintosh & Hoffman, (1984) found that Staphylococcus saprophyticus, Pseudomonas aeruginosa, Serratia spp., and Escheriscia coli were transferred from an artificially contaminated fabric to a clean fabric following hand contact. Marples & Towers, (1979) previously studied similar transmissions

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of Staphylococcus saprophyticus, and found greater transference when the fabric or hands were wet.

Sattar et al., (2001) also demonstrated that the transfer of Staphylococcus aureus from fingers to fabric occurred more when the fingertips were moist. Related to this, the working clothes and uniforms of healthcare workers have been identified as fomites (Bloomfield et al., 2011; Kreuger et al., 2012; Mitchell et al., 2015; Wiener-Well et al., 2011), which further increases the potential for transfer, with hands, clothes, and MCDs all presenting as contaminated.

4.11 Conclusion

Despite evidence that transfer can take place from a MCD to the gloved or bare hand, it cannot definitively be stated that the microorganisms on MCDs can cause infections. However, studies have shown that the microbial flora on a MCD and its user’s hand are similar, and the hands of healthcare staff have been implicated in outbreaks of infection (Boyce et al., 1990; El Shafie et al., 2004; Zawacki et al., 2004). Public Health Agency of Canada, (2012) also cited examples of healthcare workers transferring pathogens from their homes to patients. An outbreak of postoperative Serratia marcescens wound infection was traced to a contaminated jar of exfoliant cream in a nurse’s home, and the subsequent investigation identified the artificial fingernails of the nurse as the source of transmission (Passaro et al., 1997). Similarly, an outbreak of Malassezia pachydermatis in a neonatal intensive care unit in the U.S., was transmitted via the hands of a staff member, from their pet dogs (Chang et al., 1998). Following the same logic, it is not unreasonable to surmise that if a hand is contaminated by transfer from the MCD, and this hand is then responsible for patient contamination, that the MCD was therefore indirectly responsible. Consequently, as stated by Siani & Maillard, (2015, p.2):

“given that the infectious dose for most potential pathogens appears to be low, coupled with the persistence of these organisms on hospital surfaces and medical equipment for prolonged periods, the presence of a pathogen on a surface does pose a transmission and/or infection

risk”.

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Chapter 5

Evaluation of MCDs as Infection Hazards

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5.1 Introduction

This stage of the research is a qualitative ethnographic case study, to identify whether there are any infection hazards caused by introducing a MCD into the operating theatres, and if so, can these hazards be controlled? This is a bi-directional perspective, considering bacterial transfer from the device into the care setting, and contamination from the environment onto the device which may then end up in the wider health and social community.