Diversity of Streptococcal Pathogens in Throat Infections of Students on the Stetson University Campus
Stephanie Wisniski
Objective Research performed at Stetson University’s Department of Biology in conjunction with Student Health Services
Conclusions
This research was designed to study the Epidemiology,
tracking the spread of an infection and it’s source, of
streptococcal throat infections among students on the Our results indicate that our hypothesis,
Stetson University campus. that pathogens eliciting strep throat resulted
Procedures Example of DNA barcode from one isolate, that is transmitted among
To determine that the occurrence of streptococcal infections • 40 Samples were taken from October 2001 to individuals, was not supported.
is due to one isolate that is transmitted among many March 2002
individuals.
• 5 samples not showing clinical infections were Conclude that the streptococcal infections
used as experimental controls. may not be coming from one individual
Hypothesis • Registered nurse inserted 2 swabs into those passing it to another.
exhibiting red, sore throats.
The occurrence of streptococcal infections is due to one
isolate that is transmitted among individuals.
Cultured on sheep’s blood
agar plates
Introduction
This study was performed to further examine the frequency Gram stains Implications
Picture supplied by Bacterial Barcodes, Inc.
of occurrences during the past year on the Stetson campus.
Cultured in a flask
This research was of interest in hopes of
Similar procedure used by forensic scientists called DNA containing Brain Heart
Electrophoresis gels of PCR DNA fragments from university students preventing the spread of the streptococcal
Fingerprinting. Infusion (BHI)
bacteria under stressful conditions in such
stabbed into a BHI
Negative Control
close living quarters.
Positive Control
Positive Control
tube
Sample 111
Background
Ladder
Ladder
Members of the genus Streptococcus are characterized by
a spherical appearance, wells
DNA extraction Acknowledgements
a thick cell wall (gram-positive),
Centrifuge out 10 ml of organisms.
• Dr.David Stock
and appear as chains of varying length. • Ms. Hadie Kenner & Student Health Services Staff
Lyse cell membranes with 50 ul of lysozyme solution. • Kenneth Wisniski & Brian Covatta
• Dr. Alicia Schultheis
Removal of proteins, fats and carbohydrates. • Terri Blumenauer
Ethanol precipitation of DNA.
Streptococci are divided into two groups: Re-hydration in sterile TE buffer.
Literature Cited
Alpha not able to
Versalovic, J., Koeuth, T., and Lupski, J.R. 1991.
lyse red blood cells, Example of a Polymerase Chain Reaction
Results Distribution of repetitive DNA sequences in
resultant zone around
the colonies appears
(PCR) procedure eubacteria and application to fingerprinting of
No DNA fragment patterns are identical in patients bacterial genomes. Nucleic Acids Research 19:
green. sampled having streptococcal infections. 6823-6831.
Beta able to Versalovic, J., Schneider, M., DE Bruijn, F., and
completely lyse red Lupski, J.R. 1994. Genomic Fingerprinting of
blood cells, resulting in Bacteria Using Polymerase Chain Reaction.
a clear zone around Methods in Molecular and Cellular Biology 5: 25-
the colonies. 40.
DE Bruijn, F., Lupski, J.R., and Weinstock, G.
1997. Bacterial Genomes Physical Structure and
Analysis. Chapman and Hall, NY. Pages 38-48.
Left:
Some streptococcal cells may lose The working group on prevention of Invasive
their gram stain coloring with time. Group A Streptococcal Infections. Prevention of
Gel 2 Gel 1
Below: invasive group A streptococcal disease among
Streptococcal cells are gram- household contacts of case-patients: is
Table 1. Certain components of the ladder in gel 1 indicate
positive, cocci or sphere- shaped PCR of samples similarities when comparing samples to one another. prophylaxis warranted? JAMA. 1998; 279: 1206-
bacteria with a thick-layered
peptidoglycan cell wall. Quantified DNA with spectrophotometer. 1210.
Sample number Similar but not identical barcodes?
www.medic.med.uth.tmc.edu/path/00001457.html Ebell, Mark H., et al. 2000. Does this patient have
Prepared a master mix 124 & Pos.Control Yes strep throat? JAMA 284: 2912-2917.
reagents supplied in repPRO kit, 130 & 124 Yes
short nucleotide length random primer, 124 & 103 Yes
Taq DNA polymerase,
and bacterial DNA. Table 2. Certain components of the ladder in gel 2 indicate
similarities when comparing samples to one another.
Performed rep-PCR amplification in Perkin Elmer DNA Sample number Similar but not identical barcodes?
thermal cycler.
139 & Ladder Yes
Electrophoresis and staining of amplified DNA 138 & Ladder Yes
www.bact.wisc.edu/bact330/lecturespyo fragments on an agarose gel with ethidium bromide. 138 & 100 Yes