Need help with the bolded question under \'Application\'. Thanks in advance! To
ID: 99117 • Letter: N
Question
Need help with the bolded question under 'Application'. Thanks in advance!
To gain an understanding of the processes involved with identifying bacteria through biochemical tests, access Chapter 6 of the text in WileyPlus located on the Week One course page. Once in WileyPlus (Chapter 6), select the “Bacterial Identification by API” link located under the heading, Take Another Look. Once selected, review the information and watch the Flash-animated movie (animation) located within this link. Then, review the following scenario and answer the questions that follow.
Case Study
A recent outbreak of food poisoning has occurred in a community. One possible source of contamination may be the produce that is grown and distributed locally at a farmer’s market. A test sample of some of the produce revealed evidence of bacterial contamination. The bacteria sample was tested in a microbiology lab and showed the results that follow. The laboratory also performed a Gram stain of the isolated bacteria and ran a number of biochemical tests to aid identification. The biochemical tests were assayed using the Analytical Profile Index (API) 20E system for identification of Enterobacteriaceae and other gram-negative bacteria.
Figure 2. API Results of Unknown Bacteria in Text Format
Gram stain:
Gram-negative
ONPG
ADH
LDC
ODC
CIT
H2S
URE
TDA
IND
VP
GEL
GLU
Bacteria: Unknown
+
-
+
+
-
-
-
-
+
-
-
+
MAN
INO
SOR
RHA
SAC
MEL
AMY
ARA
+
-
+
+
-
+
-
+
Based on Gram stain results and the knowledge that this bacterium caused food poisoning, the laboratory is able to narrow down the possibilities to three bacterial strains. Figure 3 shows the API results:
Figure 3. API Results of Known Bacterial Strains in Text Format
Gram stain:
Gram-negative
ONPG
ADH
LDC
ODC
CIT
H2S
URE
TDA
IND
VP
GEL
GLU
Bacteria: Salmonella
-
-
+
-
-
-
-
-
-
-
-
+
MAN
INO
SOR
RHA
SAC
MEL
AMY
ARA
+
-
+
-
-
+
-
-
Gram stain:
Gram-negative
ONPG
ADH
LDC
ODC
CIT
H2S
URE
TDA
IND
VP
GEL
GLU
Bacteria: Shigella
-
-
-
-
-
-
-
-
-
-
-
+
MAN
INO
SOR
RHA
SAC
MEL
AMY
ARA
-
-
-
-
-
-
-
-
Gram stain:
Gram-negative
ONPG
ADH
LDC
ODC
CIT
H2S
URE
TDA
IND
VP
GEL
GLU
Bacteria: E. coli
+
-
+
+
-
-
-
-
+
-
-
+
MAN
INO
SOR
RHA
SAC
MEL
AMY
ARA
+
-
+
+
-
+
-
+
Application
Compare the API biochemical test results in Figure 2 (unknown bacteria from produce) with API test results in Figure 3 (known bacterial strains identified in the gray boxes on the left). The bacterial strain in Figure 3 that matches Figure 2 will identify the bacterial strain causing illness. Based upon your observations, which of the bacteria in Figure 3 is the most likely cause of the food poisoning outbreak?
Gram stain:
Gram-negative
ONPG
ADH
LDC
ODC
CIT
H2S
URE
TDA
IND
VP
GEL
GLU
Bacteria: Unknown
+
-
+
+
-
-
-
-
+
-
-
+
Explanation / Answer
When, API biochemical test results in Figure 2 were cmpared with similar results in Figure 3, it was found that the unknown bacterial strain in Figure 2 matches clisely with the strain of E.coli. Therefore, the most likely organism that could have caused the food poisoning outbreak was E.colil.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.