14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
is available electronically on http://www.sciencedirect.com
Final Abstract Number: 77.029
Session: Gram-positives & Miscellaneous Pathogens
Date: Friday, March 12, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
Streptococcus pneumoniae treatment with catecholamines affects growth based on strain
isolation site with a lack of effect on biofilm formation
X. F. Gonzales 1 , F. Quinones Falconi 2 , G. Castillo Rojas 1 , Y. Lopez Vidal 1
1 Universidad Nacional Autonoma de Mexico, Mexico, Mexico, 2 National Institute of Respiratory
Diseases, Mexico, Mexico
Background: It is known that bacterial physiological responses are affected by catecholamines
(norepinephrine, epinephrine) in vitro. Considering that catecholamines participate in stimulating
growth in bacteria such as E. coli and development of biofilms with Salmonella. Along with
observations of the effect of catecholamines on oral Streptococcal species, not including
Streptococcus pneumoniae, revealing a varied affect on growth and biofilm formation between
species. S. pneumoniae is the most common cause of bacterial pneumonia worldwide and is
known to develop biofilms in otits media infections. We aim to determine if norepinephrine
stimulates S. pneumoniae growth and biofilm formation in vitro, and if the clinical isolation history
of the bacteria is a factor in this response. The gathered data will provide information on
catecholamine participation on pathogenesis.
Methods: Four clinical strains of S. pneumoniae of which two were isolated from nasal swabs
and two from blood samples were cultured in Todd Hewitt broth with yeast extract; treated culture
included 10-4M of norepinephrine or epinephrine. Biofilm experiments utilized cell-culture
microtiter plates in which control and treated bacteria were added to respective wells and
incubated for 24 hrs. Changes in growth and biofilm formation were determined by measurement
of optical density.
Results: The data revealed a 4 to 6 fold increase in growth in catecholamine treated S.
pneumoniae collected from blood samples, while a 3 to 4 fold increase in nasal swab samples as
compared to non treated cultures. Catecholamine treatment of S. pneumoniae revealed no
significant difference in the formation of biofilms.
Conclusion: The results demonstrate that S. pneumoniae exposed to catecholamines increases
growth which could allow for increased colonization of the bacteria in the respiratory tract thereby
increasing the chances of infection. The difference in the magnitude of fold increase in blood
samples versus nasal swab samples could indicate that cultures vary there responses to
catecholamines as infection enhances. Biofilm data shows that there is no significant difference
in biofilm formation 24hrs post treatment versus control indicating that catecholamines have no
affect on stimulating biofilms in S. pneumoniae in vitro.