NOCOSOMIAL infections – those
acquired in hospitals – have caused
concern in the healthcare
professions since the 1800s.
Methicillin-resistant Staphylococcus
aureus (MRSA) has been the most
talked about infection of late, although
recent reports suggest that MRSA
rates in human
hospitals have fallen
to a quarter of the
level at the peak in
2004 and Clostridium
difficile rates have also
fallen by a third in the
last year. E. coli has,
however, increased by
a third and it has been
estimated that there is
no robust data on
80% of the organisms
linked to hospital
care.
As yet the level of
infection in veterinary
hospitals remains low and this has
been attributed to less intensive
medical practices and shorter stays
within the hospital environment.
Speaking at the WSAVA congress
in 2008, Dr Frederic Gaschen of
Lousiana State University predicted
that this picture could alter radically.
“The situation is changing rapidly: the
improvement of standards of care for
critical small animal patients is one
factor that may lead to an increase of
nocosomial infections. Multi-drug-
resistant bacteria could become a
serious threat in our practices and
hospitals very soon if we do not act in
time,” he said.
Transmission and colonisation
Individuals, both animal and human,
may be previously colonised by
organisms and this can be a risk factor
for hospital-acquired infections.
Colonised individuals may remain in
that state without any detrimental
effects but certain insults, such as
debilitating illness or treatment with
multiple antibiotics, can lead to the
individual developing an active
infection.
Other risk factors can include the
use of indwelling devices such as
catheters, length of hospital stay and a
high nurse:patient ratio; while
infections occurring during surgery can
be affected by the duration of surgery
and anaesthesia, emergency versus
daytime surgery and the number of
people in the operating theatre.
The main source of infection in
hospital-acquired infections is the
hands of healthcare workers who
transmit infections derived from
infected patients or colonised patients
or health workers, to other patients and co-workers. Environmental
contamination also presents a risk and
in some cases airborne transmission
can be significant.
Species specific
In dogs and cats, the most common
presentations of hospital-acquired infections are deep
wound infections and
urinary tract
infections, although
pneumonia and
endocarditis have
also been reported.
In 2006, in a
survey of Irish
veterinary practices,
MRSA was isolated
from 8% of dogs
with clinical
infections and 0.6%
of healthy dogs; and
9% of dogs sampled in the Royal
Veterinary College animal hospital were also positive on sampling.
Strains isolated from dogs and cats usually match human strains found in
the area, suggesting that pets are
colonised by people, but subsequently
the pets can also be a source of
infection for other people. Recurrent
infections in people treated for MRSA
have been linked to their pets.
One recent study also found that
the presence of a cat could increase
the likelihood of environmental
contamination by MRSA in the home
eight-fold5. It has been postulated that
grooming through licking or an
increased tendency for cats to have
access to work surfaces may be leading
to increased dispersal of the bacteria.
Other at-risk species include pigs
and horses. In horses, strangles,
salmonellosis and rotavirus diarrhoea
are all significant considerations in the
hospital environment. MRSA has also
been identified in horses and there are
case reports of horse to human
transmission. One study has also
suggested that indirect transmission
through environmental contamination
could be significant in horses.
In 2008, a survey of veterinary
attendees at a conference on pig health
in Holland found that 12.5% were
colonised by MRSA, compared to just
0.03% of the general Dutch
population.
While colonised vets or nurses
may remain healthy, there exists the
possibility that they will in turn
colonise vulnerable patients. Studies
suggest that 20-40% of veterinary
staff are colonised, which is higher
than the norm in the UK population,
and clusters of infected pets have
been identified in association with colonised veterinary staff.
It is widely acknowledged, however, that the levels of colonisation as a
whole are high enough in the UK that
identification and treatment of all
healthcare workers colonised by MRSA
is impractical.
Clostridium difficile was identified in
one study in 11% of dogs on admission
to an ICU unit, rising to 18% during
hospitalisation, with 69% of the isolates
reported to be toxigenic. Multi-drug-
resistant E. coli has been reported in an
intensive care unit in the US and
vancomycin resistant Enterococcus has
been identified in small numbers of
healthy dogs3.
Find out more
The Bella Moss Foundation provides an
on-line training course for practice
personnel, which includes instructions
on good hand washing techniques and
advice on barrier nursing. Visit
www.veterinarynursetrainingonline.org.
There is also some excellent detailed
advice on the BSAVA website with
regard to MRSA, managing patients and
controlling the risks in the practice, at
www.bsava.com/Advice/MRSA/tabi…
171/Default.aspx.
References
- As reported by BBC News, 10th
November 2009. - Nocosomial Infection: Prevention and
Approach, by Frederic Gaschen. In:
Proceedings of the 33rd World Small
Animal Veterinary Congress 2008, Dublin. - Hospital Acquired Infections, by Amanda
BoagL The London Vet Show, 2009. - MRSA: Current Status and the Future, by
Finola Leonard. In: Proceedings of the 33rd
World Small Animal Veterinary Congress
2008, Dublin. - As quoted at
www.vetpulse.tv/blog/687_spotlight-on-
mrsa-infection-between-pets. - Infection Control Strategies, by J Traub-
Dargatz. In: Proceedings of NAVC, January
2005. - Review of Methicillin-Resistant
Staphylococcus aureus in Horses and Veterinary
Personnel who work with horses, by M.
Anderson and J. Scott Weese. In:
Proceedings of the 54th Annual Convention
of the American Association of Equine
Practitioners. - Prevalence of MRSA in Veterinarians
Attending the IPVS, by M. W. H. Wulf et al.
In: Proceedings of the International Pig
veterinary Society Congress, 2008. - J. Scott Weese et al (2008) Prevalence and
risk factors for Clostridium difficile colonization
in dogs and cats hospitalised in an intensive
care unit. Veterinary Microbiology 129 (1-2):
209-214.
