Survival of Microorganisms on Inanimate Surfaces - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 9

Because of this, the knowledge on the survival of bacteria, fungi, viruses and
protozoa on surfaces, and hence, in a broader sense, in the human environment, is
important for planning and implementing tactics for prevention of Healthcare-acquired
Infections (HAI). Furthermore, such knowledge will also assist ensuring the biosafety
in microbiological and biomedical laboratories, food-handling settings, and for
hygienic behaviour in the everyday life to prevent transmission of infectious diseases.
One example of microorganisms with relatively short ability of persisting in the
environment is the severe acute respiratory syndrome (SARS) coronavirus (CoV),
which became pandemic within months in China in 2002. This virus retains
infectivity on different substrates up to 9 days, as compared to the influenza
virus, which demonstrates a relatively long persistence in the environment up to
4 weeks [ 112 ]. Both viruses are airborne transmitted infectious agents, however,
they may also be transmitted via hand-surface contacts, supporting the relevance of
hand hygiene and personal protection against infection.
Because of a number of microorganisms' ability to persist and survive for long-
term periods on surfaces, particularly in healthcare settings, the usage of
antimicrobially impregnated surfaces is increasingly discussed [ 82 ]. However,
because of the required long contact times of microorganisms on antimicrobial
surfaces [ 64 , 65 , 25 , 45 ], such technologies may be useful for surfaces with low
frequency of hand contacts.
2.2 The Role of Surfaces in the Transmission of Pathogenic
Microorganisms Causing Healthcare-Acquired
Infections (HAI)
In healthcare settings, bacteria, bacterial spores, viruses and yeasts are mainly
transmitted from infected and/or colonized patients, but also from staff, and in
some situations from visitors to the inanimate hospital environment, particularly to
areas adjacent to patients and frequently touched surfaces by hands (“high-touch
surfaces”). Potential pathogenic microbial flora of the respiratory tract and of the
vestibulum nasi, such as methicillin- sensible (MSSA) or resistant Staphylococcus
aureus (MRSA), is correlated with a higher risk of contamination of surrounding
surfaces through direct or indirect contact with hands [ 81 ]. Intestinal infections
caused i.e. by Clostridium difficile and Norovirus, or enteral colonization with
nosocomial pathogens such as vancomycin-resistant enterococci (VRE) may also
be associated with a risk of widespread environmental contamination [ 30 ]. Compared
with the large number of published literature on environmental contamination with
MRSA, VRE, and C. difficile , there are relatively few published studies on environ-
mental contamination by Gram-negative bacteria [ 64 , 65 ]. Aside of a possible
publication bias in the past, one reason for this is the different ability of Gram-
positive and Gram-negative bacteria to survive in the inanimate environment.
The level of microbial bio-burden on surface in healthcare settings is low compared
to the numbers on patients' skin or in faeces. However, even at low particle numbers