Memorandum by the Association of Clinical
1. What are the main problems facing the
surveillance, treatment and prevention of human infectious disease
in the United Kingdom?
Oral infectious diseases rarely obtain a high
profile as a distinct disease entity. However, oral diseases caused
either directly or indirectly by micro-organisms contribute to
a significant degree of morbidity within the population of the
UK. Dental caries, caused in part by cariogenic micro-organisms,
such as Streptococcus mutans, results in millions of episodes
of dental treatment throughout the country on an annual basis
A common sequel of dental caries is a dental abscess which may,
even today, lead to life threatening infections despite the use
of antibiotic treatment. Antibiotics are frequently prescribed
for oral diseases and there is compelling evidence to suggest
that the majority of these prescriptions are unnecessary,
However, there is little in the way of surveillance of the micro-flora
involved in oral infections and their susceptibility to various
antimicrobial agents. A recent multi-centre study funded by the
Scottish Executive Health Department (Grant No. CZG/4/2) highlighted
the difficulties in obtaining sufficient high quality specimens
for microbiological analysis, particularly from primary care.
There is evidence to suggest that antibiotic resistant determinants
from members of the oral flora have been transmitted to other
more virulent relatives. This is best demonstrated by the spread
of penicillin resistance genes from Streptococcus oralis to Streptococcus
illustrating the importance of surveillance of micro-organisms
in the oral cavity.
Periodontal disease, in its many guises, also
affects a large proportion of the UK population, and is caused
in part by a wide variety of anaerobic micro-organisms. Recent
research has suggested a possible link between periodontal disease
and a number of systemic conditions, such as heart disease and
in the induction of pre-term birth and low birth weight children.
Much research has been performed on the microbiology of periodontal
disease but the prevention and treatment of periodontal disease
has changed very little over the last decade. Considerable use
of the antibiotic metronidazole is made in the treatment of periodontal
disease and this probably accounts for the reason why dental prescriptions
of metronidazole represent the largest number of prescriptions
for this antibiotic in the community. The widespread use of metronidazole
may have contributed to the increased burden of metronidazole
resistance in Helicobacter pylori, a well documented aetiological
agent in stomach cancer.
Candida (yeast) infections of mucosal surfaces
(thrush) are extremely common, debilitating, distressing and often
recurring. Candida albicans is carried as a common commensal fungus
at low levels in the oral cavities of approximately 50 per cent
of healthy individuals but candidosis can result when host conditions
allow the organism to express virulence factors and proliferate
to high numbers. Infection of the mouth by Candida albicans can
be problematic, particularly in denture wearing patients and is
commonly underdiagnosed and mistreated. Oral infections particularly
in the more vulnerable members of society, such as the terminally
ill and nursing home residents, frequently cause considerable
morbidity and can be difficult to treat. Antifungal agents can
produce clinical improvement but relapses are common. New treatments
and vaccines are thus desperately needed.
The relationship between oral micro-organisms
and systemic disease is classically illustrated by infection with
oral micro-organisms of damaged heart valves following dental
treatment. A few cases have been reported highlighting problems
with increased antimicrobial resistance in these types of infections.
Of interest is the increasing body of evidence to suggest that
the oral cavity may be the source of other micro-organisms, such
as Staphylococcus aureus, that are well documented pathogens,
particularly in implanted devices such as prosthetic joints.
In summary, oral infectious diseases contribute
significant morbidity to the UK population, but the surveillance
of these infections, particularly in the community, has received
scant attention from public health bodies. Improvements in the
detection, monitoring, treatment and prevention of oral infectious
diseases would not only impact on the quality of oral health but
are also likely to lead to improvement in general health.
2. Will these problems be adequately addressed
by the government's recent infectious disease strategy, "Getting
Ahead of the Curve?"
There is no strategy to address the issues highlighted
for combating oral infectious diseases.
3. Should the United Kingdom make greater
use of vaccines to combat infection and what problems exist for
developing new, more effective or safer vaccines?
Yes. UK immunology is very strong and has been
at the forefront of development of the new generation of vaccines
at mucosal surfaces which allow for ingestion or nasal inoculation
of the vaccine rather than by injection, for example, influenza.
Indeed the first vaccine to be engineered in plants was against
Streptococcus mutans. The potential for locally delivered immunotherapeutics
is undoubted but what the microbial targets of such treatments
should be remains unclear. Although some bacterial species are
strongly associated with oral infection, we remain largely ignorant
of the composition of the bacterial communities in oral health
and disease. Much fundamental work is required to comprehensively
describe the oral microflora and investigate which species are
associated with disease. It is recognised that oral infections
result from a complex interaction between the host and the normal
microflora. Better understanding of this interaction will lead
to novel prevention and treatment options. Other problems include
financial support to maintain the UK at the forefront of vaccine
technology and establishing long term efficacy of vaccines.
4. Which infectious diseases pose the biggest
threats in the foreseeable future?
The Department of Health risk assessment for
the potential transmission of variant Creutzfeldt-Jakob disease
(vCJD) via surgical instruments has highlighted the potential
for transmission via this route. Dental treatment accounts for
the most common healthcare intervention involving surgical instruments
in the UK. It has already been suggested that reductions in dental
disease would play a role in reducing the number of these interventions
and therefore use of dental instruments.
Strategies to improve the decontamination of
dental instruments would do much to reduce the risk of onward
transmission not only of vCJD but of other infectious diseases
such as hepatitis C. However, despite the large number of dental
treatment episodes there is no on-going surveillance of infection
following dental treatment, making it difficult to provide pragmatic
advice on the decontamination of dental instruments.
5. What policy interventions would have the
greatest impact on preventing outbreaks of and damage caused by
infectious disease in the United Kingdom?
In order to reduce the impact of oral infectious
diseases a considerable effort must be devoted to improving the
oral health of the nation.
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