VaporPrintTM of
Infectious Bacteria Cultures
Strep
pneumonia
Shigella
flexneri
Salmonella
typhimurium
Klebsiella
pneumonia
Pseudomonas
aeruginosa
Candida albicans
Fresh
Nutrient
Staph aureus
Hemophilus
influenza
Electronic
Sensor
Technology
Salmonella
enteritidis
Enterococcus
faecalis
E. Coli
E. Coli O157
Cultures Prepared by: Department of Pathology and Laboratory
Medicine, State Public Health Laboratory of Nevada
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1
An Investigation of Infectious Bacteria
With a GC/SAW Electronic Nose
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Water based cultures were inoculated with 12 infectious bacteria and allowed to incubate at
37oC for 24 hours before analyzing headspace vapors with GC/SAW Electronic nose. Two of
the twelve cultures did not develop and contained no bacteria.
Headspace vapor of cultures without bacteria displayed two primary nutrient analyte peaks
and three small analyte peaks located midway between the two nutrient peaks.
Bacteria growth dynamically interacted with nutrient compounds as well as created new
analyte vapors specific to the bacteria itself. The concentrations of new analytes together
with modified nutrient vapors created VaporPrintsTM images specific to bacteria type.
E.Coli and E.Coli )157 produced nearly identical VaporPrintsTM, however, one analyte was
found to be specific to only O157.
In general each bacteria type could be recognized by its unique VaporPrintTM image.
Bacteria Tested
1. Strep pneumonia
2. Hemophilus influenza
3. Candida albicans
4. Shegella flexneri
5. Staphylococcus aureus
6. Pseudomonas aeruginosa
7. Salmonella enteritidis
8. Enterococcus faecalis
9. Klebsiella pneumonia
10 Escherichia coli O157
11 Escherichia coli (benign)
12 Salmonella typhimurium
Electronic
Sensor
Technology
Ease of
Summary of Results
Identification
0
0
4
5
3
10
7
5
10
10
10
10
Negative Culture Growth
Negative Culture Growth
Doubled 2nd nutrient peak and 2 persursors
Nutrients diminished, percursor and precursor ripples
Increased nutrients, doubled 2nd
Reduced 1st nutrient, 10X new ripple peak
Reduced 1st nutrient, Large percursor peak
Reduced 1st nutrient, Large increase in 2nd
Reduced nutrients, large new ripple and percursors
Reduced 1st, increased 2nd, large post, added ripple
Same as O157 except 4th ripple peak not present
Reduced nuturients, large new ripple, precursors
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2
No Growth Confirmed
for Hemophilus influenza and Strep pneumonia Culture Bottles
Strep pneumonia
Nutrient Broth
Hemophilus influenza
Nutrient Broth
Analytes Present in Nutrient Broth
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Post Peaks (1)
Electronic
Sensor
Technology
Retentio
n Time
Amount after
24 hr @ 37 o C
6.8
10.3
7.8
8.2
9
12.5
362
749
10
26
151
55
Quantitative results based upon no-growth
chromatograms of H. influenza and S. pneumonia
Small set of 3 peaks prominent and generally always
present but much smaller than primary nutrient peaks
Broad low vapor pressure compounds generally present
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3
Candida albicans
Analytes Present in Candida albicans
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
New Peaks (2)
Post Peaks (1)
Retentio
n Time
Amount after
24 hr @ 37 o C
6.8
10.2
7.8
8.2
9.0
3.14
5.26
12.26
344
1383
10
26
169
40
111
127
First peak unchanged but second doubled
ripple peaks unchanged
Two new perecursor peaks, very distinctive
Doubled heavy compounds
Candida albicans
Nutrient Broth
Electronic
Sensor
Technology
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4
Shigella flexneri
Analytes Present in Shegella flexneri
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Precursor Peaks (4)
Post Peaks (1)
Retention
Time
Amount after
24 hr @ 37 o C
7.1
10.5
7.8
8.2
9.0
3.22
4.9
5.42
5.98
12.26
172
399
10
26
155
30
26
23
11
32
First peak almost gone and second greatly reduced
ripple peaks unchanged
(1) percursor peak
(3) new persursor ripple peaks
unchanged small mixture
Shigella flexneri
Nutrient Broth
Electronic
Sensor
Technology
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5
Staphylococcus aureus
Analytes Present in Staphylococcus aureus
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Post Peaks (1)
Retention
Time
Amount after
24 hr @ 37 o C
6.74
10.22
7.8
8.2
9.0
12.26
522
1711
10
26
155
159
First peak slight increase and second doubled++
ripple peaks unchanged
well defined unchanged
Staph aureus
Nutrient Broth
Electronic
Sensor
Technology
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6
Pseudomonas aeruginosa
Analytes Present in Pseudomonas aeruginosa
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Precursor Peak (1)
Post Peak (1)
Retention
Time
Amount after
24 hr @ 37 o C
6.78
10.22
7.8
8.2
8.9
3.1
12.26
202
330
10
26
5170
31
32
First peak almost gone and second slightly reduced
first two ripple peaks unchanged but third is 10 times
larger than nutrient peaks
(1) percursor peak
unchanged small mixture
Pseudomonas aeruginosa
Nutrient Broth
Electronic
Sensor
Technology
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7
Salmonella enteritidis
Analytes Present in Salmonella enteritidis
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Precursor Peak (1)
Post Peaks (1)
Retention
Time
Amount after
24 hr @ 37 o C
6.94
10.18
7.8
8.2
9.0
3.1
11.5
250
546
10
28
155
327
25
First peak almost gone and second unchanged
ripple peaks unchanged
(1) percursor peak as big as nutrient peaks
unchanged small mixture
Salmonella enteritidis
Nutrient Broth
Electronic
Sensor
Technology
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8
Enterococcus faecalis
Analytes Present in Enterococcus faecalis
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Precursor Peak (1)
Post Peaks (1)
Retention
Time
Amount after
24 hr @ 37 o C
6.74
10.18
7.8
8.2
9.0
2.34
12.26
391
1693
10
26
155
16
141
First peak slight decrease and second greatly
increased
ripple peaks unchanged
(1) small percursor peak
distinctive small peak
Enterococcus faecalis
Nutrient Broth
Electronic
Sensor
Technology
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9
Klebsiella pneumonia
Analytes Present in Klebsiella pneumonia
Primary Nutrient
Peaks (2)
Ripple Peaks (4)
Precursor Peaks (2)
Post Peaks (1)
Retention
Time
Amount after
24 hr @ 37 o C
6.94
10.26
7.8
8.2
9.0
9.5
1.02
3.1
11.46
272
169
10
26
155
549
30
165
169
Both nutrient peaks reduced
original (3) ripple peaks unchanged but with a fourth
large new peak
(2) distinctive percursor peaks
large grouping of post peaks
Klebsiella pneumonia
Nutrient Broth
Electronic
Sensor
Technology
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10
Escherichia coli O157
Analytes Present in Escherichia coli O157
Primary Nutrient
Peaks (2)
Ripple Peaks (4)
Post Peaks (1)
Retention
Time
Amount after
24 hr @ 37 o C
6.7
10.26
7.8
8.2
9.0
9.5
11.22
129
510
10
26
155
100
2135
early peak reduced and second peak increased
original (3) ripple peaks unchanged but with a fourth
new peak
large new post peak
E. coli O157
Nutrient Broth
Electronic
Sensor
Technology
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11
E. coli (benign)
E. Coli (benign)
Nutrient Broth
Analytes Present in Escherichia coli (benign)
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Post Peaks (1)
Electronic
Sensor
Technology
Retention
Time
Amount after
24 hr @ 37 o C
6.7
10.26
7.8
8.2
9.0
11.22
129
510
10
26
155
4002
early peak reduced and second peak increased
original (3) ripple peaks unchanged
large new post peak
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12
Comparison of E. coli
E. coli O157
E. coli (benign)
Specific to
O157 E. Coli
Electronic
Sensor
Technology
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13
Salmonella typhimurium
Salmonella typhimurium
Nutrient Broth
Analytes Present in Salmonella typhimurium
Primary Nutrient
Peaks (2)
Ripple Peaks (3)
Precursor Peak (2)
Post Peaks (1)
Electronic
Sensor
Technology
Retention
Time
Amount after
24 hr @ 37 o C
6.86
9.94
7.8
8.18
9.0
0.94
3.42
10.9
608
522
10
1792
155
1281
175
25
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First peak reduced and second almost gone
large new ripple peak
(2) distinctive percursor peaks
many low volaltility analytes present
14