The Role of Contaminated Surfaces in the Transmission of Nosocomial Pathogens - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 30

C. difficile [14,15]

Contaminated
surfaces or
equipment

VRE [18,19]
Gram-negatives [20,21]

Contaminated inanimate objects implicated in
transmission [3,4]

Hands can acquire pathogens from
surfaces [16,22,23]

Hands can acquire
pathogens from
patients [22]

Contaminated hands
transmit pathogens [24]

Infected or
colonised
patient

Contaminated
healthcare
workers' hands

Susceptible
patient

Pathogens can contaminate air [25,26] Contaminated air implicated in transmission [27]

Contaminated
air

Direct patient contact [ 28 ]

Fig. 3.1 Generic transmission routes

Pathogen transfer from an affected patient to a susceptible host occurs most
commonly via the hands of healthcare personnel (HCPs) but contaminated objects,
surfaces and air can be either directly or indirectly involved in the transmission
pathway (Fig. 3.1 ). Here we review evidence that nosocomial pathogens are shed
by patients and can contaminate hospital surfaces at concentrations sufficient for
transmission, can survive for extended periods, can persist despite attempts to
disinfect or remove them and can be transferred to the hands of HCPs. We also
review evidence that improved environmental hygiene can help to bring outbreaks
under control and reduce endemic nosocomial transmission, and consider the
various options to address contaminated surfaces in healthcare facilities.

3.2 Pathogens Are Shed into the Hospital Environment

Several important pathogens including C. difficile , MRSA, VRE, A. baumannii,
P. aeruginosa and norovirus are shed by patients and contaminate surfaces in
hospitals, which may serve as a source for transmission. Fungi, in particular
Aspergillus spp., can also contaminate the hospital environment and cause HAI;
however, fungi are a special group with unusual features that have been well-
reviewed elsewhere and will not be considered here [ 27 ].
Bacteria, spores and viruses are shed from infected and/or colonized patients
(and sometimes staff) into the hospital environment. Wide variation in the reported
frequency of environmental contamination can be explained by several factors,
including the culturability of the organism, the degree of shedding by the patient,
the sampling methodology, the ease of contamination (or difficulty of cleaning) of