Pseudomonas Aeruginosa
Mayra Aguilar
DH109
Infection control
Pseudomonas Aeruginosa
10/13/08
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Pseudomonas Aeruginosa
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Water delivered by dental water unit systems in general dental practices can
harbor high numbers of bacteria, including opportunistic pathogens. (Schel, Marsh,
Bradshaw, Finney, Fulford, Frandsen 2008) Dental water lines can be colonized by
different types of bacterial biofilm. One of these types of bacteria includes Pseudomonas
aeruginosa which is a type of bacteria that can cause serious problems in
immunocompromised patients. First, I will explain where pseudomonas is found, why it
is of clinical relevance, when it can cause disease, and the things that can be done to
minimize the exposure of this organism to dental patients.
According to Todar (2008), Pseudomonas aeruginosa is a free-living bacterium,
commonly found in soil and water. It has become increasingly recognized as an emerging
opportunistic pathogen of clinical relevance. The bacterium almost never infects
uncompromised tissues, yet there is hardly any tissue that it can not infect if the tissue
defenses are compromised in any manner. Pseudomonas can cause urinary tract
infections, respiratory system infections, dermatitis, soft tissue infections, bacteremia,
bone and joint infections, gastrointestinal infections, and a variety of systemic infections.
As we can see this is an organism that can cause many different types of infections
especially in people that don’t have a healthy immune system.
Immunocompromised patients are more prone to getting an infection from
pseudomonas than other people with normal immune systems since this is an
opportunistic pathogen. For instance, according to Rodriges, Shenoy, and Joseph (2005),
a report from England showed that two cancer weakened dental patients acquired oral
infections with Pseudomonas aeruginosa that originated from dental unit water, the same
study also showed that an additional 78 patients treated at the same dental unit were
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orally colonized for 4-10 weeks by P.aeruginosa present in the dental unit water. This
shows that anyone can become infected with this type of microorganisms, but people
with compromised immune systems are at risk of developing a more serious condition.
Furthermore, the most common infective agent on people with cystic fibrosis is
Pseudomonas aeruginosa as it can cause increased inflammation of the respiratory tract.
(Mayo Clinic 2008) Seeing all the problems that this microorganism can cause, the most
important thing that health care workers can do is to protect these patients by making sure
that they are not exposed to Pseudomonas during dental treatment. We need to remember
that not all people are healthy enough to fight an infection that otherwise would not cause
a serious reaction.
Furthermore, there are many things that can be done to prevent the growth of
biofilm in dental waterlines. For example, according to Rodrigues, Shenoy, and Joseph
(2005), antiretraction valves are fitted on modern handpieces to reduce oral suck back
from the oral cavity preventing a retrograde infection. Anti retraction valves can also be
fitted on the waterlines. I think that using antiretraction valves can help limit cross
contamination if it is used in a correct way and if workers make sure that it is working
properly. Also, flushing the dental waterlines for 2 minutes at the start of the day and for
20-30 seconds between patients will reduce the bacterial count by approximately 97%;
however, it will not reduce the total count to less than 200 cfu/ml nor will it remove the
biofilm. (Rodrigues, Shenoy, Joseph, 2005) Even though biofilm is not completely
removed, flushing water lines would help make sure that we are not exposing patients to
bacterial amounts that could cause any harm to them. If it only takes a few minutes to
ensure the well being of individuals, then it is worth doing it. In addition, according to
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McDowell (2004), a proactive approach is taken by a new product, A-dec ICX waterline
tablets (A-dec Newburg, Ore.), an effervescent tablet that is added directly to the dental
unit water bottle at each refill. According to this article the six treated units, showed no
appreciable bacterial counts-less than 3 CFU/mL- during the 16-week study. Biofilm
development in the untreated control test units, produced effluent counts that rapidly
exceeded those of the innoculum population. This article shows that dental water units
that were not treated with the product, had an increase in bacterial biofilm than the ones
that were exposed to the product. Using a product that inhibits the growth of bacteria
could be a better solution than just flushing water lines. It seems like it would be safer to
use some kind of product like the one being used in this experiment in order to ensure the
safety of water used for dental treatment. There are different methods to lower the
amount of biofilm present in dental unit water lines, and the one that works better should
be used to reduce the risk of exposure to patients.
Finally, according to Schel (2006), patients in the EU visit general dental
practices every six months, with over 20 million visits per year in one large EU country
alone. During almost every visit, the patient and the dental health care staff are exposed
to the water from DUWS. As a result, as dental health care workers, it is our
responsibility to make every effort to protect patients from being exposed to something
that can cause them harm. While not all microorganisms can cause harm to patients, we
need to remember that there are a few of them that will cause infection if the patient’s
immune system is compromised. We have to remember that it is very important that we
follow guidelines that have been set to protect patients from contamination in the dental
office. If it only takes us two minutes to flush the water lines and make sure that water is
Pseudomonas Aeruginosa
safe, then we should make sure that we do it. Patients come to a dental office to make
sure that their oral health is improved, so they should not be exposed to any type of
contamination that can worsen their overall health.
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References
Mayo Clinic. (2008). Cystic fribrosis. Retrieved October 13, 2008, from
http://www.mayoclinic.com/health/cystic-fibrosis/DS00287
McDowell, J.W., Paulson, D.S., Mitchell, J.A., (2004). A simulated-use evaluation of a
strategy for preventing biofilm formation in dental unit waterlines. The Journal of
the American Dental Association, volume 135,(issue 6). Retrieved October 11,
2008, from http://jada.highwire.org/cgi/content/full/135/6/799
Rodrigues, S., Shenoy, V., Joseph, M. (2005). Changing face of infection control: Dental
unit water lines. The Journal of Indian Prosthodontic Society, volume 4(issue 4).
Retrieved October 10, 2008, from http://www.jprostodont.com/article.asp?issn=
09724052;year=2005;volume=5;issue=4; space=170;epage=174;aulast=Rodrigues
Schel, A.J, Marsh, P.D., Bradshaw, D.J., Finney, M., Fulford, M.R., Frandsen, E. et al.
(2006). Comparison of the efficacies of disinfectants to control microbial
contamination in dental unit water systems in general dental practices across the
European Union. Applied and Environmental Microbiology, volume 72(2).
Retrieved October 13, from 2008,http://www.pubmedcentral.nih.gov/articlerender.
fcgi?tool=pmcentrez&artid=1392914
Todar, K. (2008). Pseudomonas aeruginosa. Todar’s Online Textbook of Bacteriology.
Retrieved October 13, 2008, from http://textbookofbacteriology.net/pseudomonas.
html