Lab 14: Unknown Worksheet
Learning Objectives:
• Apply knowledge acquired in the laboratory exercises
• Predict the identity of an unknown bacteria in the given case study
• Based on the two dichotomous keys given, answer the following case studies. For each case
study you should write 1-2 paragraphs, using complete sentences, as to how you arrived at your
conclusion. You should take us step by step through the process AND indicate how you ruled out
other microorganisms. Simply saying I used the dichotomous tree isn’t sufficient.
Case Study 1:
Justin was spending the summer with his father on their ranch in Wyoming. One day, as they were
clearing brush and branches from a deserted barn, Justin was struck in the eye with a tree branch. Part of
the tree branch penetrated Justin’s eye. The eye continued to worsen over the next few days and Justin’s
father took him to the emergency room. A culture was performed with the results shown below. Based on
the dichotomous tree, what organism has infected Justin’s eye.
Case Study 2:
Sharon just graduated from high school and her parents took her on a celebration trip to Venezuela. On
the trip, Sharon and her family visited many small villages and Sharon had the opportunity to experience
life in these villages. Sharon and her family were treated to local cuisine made from fresh vegetables. On
the final day of the trip Sharon and her family all came down with an intense case of diarrhea. Lab tests
were performed with the results shown below. Based upon the dichotomous chart, what organism caused
the diarrhea?
Case Study 3:
Jennifer was a new nurse at the local hospital. She had recently passed her NCLEX exam and was excited
to be working at her dream job. Jennifer was asked to start an IV on a heart patient so that they could give
the patient IV medications. She was thrilled for the opportunity to show off her excellent skills at starting
IVs. As Jennifer removed the cap from the needle, she accidentally brushed the needle against the skin on
her forearm. Jennifer knew that she should get a new needle but she was concerned that she would get in
trouble so went ahead and used the needle to start the IV. The next day, the heart patient spiked a fever
and showed other indications of septic infection. Blood cultures were ordered and the results are shown
below. Using the dichotomous tree, determine the organism that is causing problems for the heart patient.
Case Study 4:
Juanita was happy and excited about the birth of her new baby boy Joshua. Although Joshua was born
prematurely, he thrived in the hospital and was released two weeks after birth. On the fifth day at home,
Juanita noticed that Joshua wasn’t interested in breast feeding and that he seemed lethargic. Juanita
became more concerned when she noticed red spots on the blanket she used when breast feeding.
Fearing that there was a major problem, Juanita took Joshua to the hospital. The hospital asked Juanita
for some expressed breast milk which was sent to the laboratory for culture. The results of the culture are
below. Based on the dichotomous tree, what organism is causing problems for Joshua?
Questions:
In this lab you used a dichotomous tree to identify your unknown bacteria. Please describe what a
dichotomous tree is, how it is used, and the importance of such a tree.
This study source was downloaded by 100000898182462 from CourseHero.com on 05-06-2025 00:11:25 GMT -05:00
https://www.coursehero.com/file/238247047/Identifying-Bacterial-Infections-Case-Studies-Dichotomous/
Learning Objectives:
• Apply knowledge acquired in the laboratory exercises
• Predict the identity of an unknown bacteria in the given case study
• Based on the two dichotomous keys given, answer the following case studies. For each case
study you should write 1-2 paragraphs, using complete sentences, as to how you arrived at your
conclusion. You should take us step by step through the process AND indicate how you ruled out
other microorganisms. Simply saying I used the dichotomous tree isn’t sufficient.
Case Study 1:
Justin was spending the summer with his father on their ranch in Wyoming. One day, as they were
clearing brush and branches from a deserted barn, Justin was struck in the eye with a tree branch. Part of
the tree branch penetrated Justin’s eye. The eye continued to worsen over the next few days and Justin’s
father took him to the emergency room. A culture was performed with the results shown below. Based on
the dichotomous tree, what organism has infected Justin’s eye.
Case Study 2:
Sharon just graduated from high school and her parents took her on a celebration trip to Venezuela. On
the trip, Sharon and her family visited many small villages and Sharon had the opportunity to experience
life in these villages. Sharon and her family were treated to local cuisine made from fresh vegetables. On
the final day of the trip Sharon and her family all came down with an intense case of diarrhea. Lab tests
were performed with the results shown below. Based upon the dichotomous chart, what organism caused
the diarrhea?
Case Study 3:
Jennifer was a new nurse at the local hospital. She had recently passed her NCLEX exam and was excited
to be working at her dream job. Jennifer was asked to start an IV on a heart patient so that they could give
the patient IV medications. She was thrilled for the opportunity to show off her excellent skills at starting
IVs. As Jennifer removed the cap from the needle, she accidentally brushed the needle against the skin on
her forearm. Jennifer knew that she should get a new needle but she was concerned that she would get in
trouble so went ahead and used the needle to start the IV. The next day, the heart patient spiked a fever
and showed other indications of septic infection. Blood cultures were ordered and the results are shown
below. Using the dichotomous tree, determine the organism that is causing problems for the heart patient.
Case Study 4:
Juanita was happy and excited about the birth of her new baby boy Joshua. Although Joshua was born
prematurely, he thrived in the hospital and was released two weeks after birth. On the fifth day at home,
Juanita noticed that Joshua wasn’t interested in breast feeding and that he seemed lethargic. Juanita
became more concerned when she noticed red spots on the blanket she used when breast feeding.
Fearing that there was a major problem, Juanita took Joshua to the hospital. The hospital asked Juanita
for some expressed breast milk which was sent to the laboratory for culture. The results of the culture are
below. Based on the dichotomous tree, what organism is causing problems for Joshua?
Questions:
In this lab you used a dichotomous tree to identify your unknown bacteria. Please describe what a
dichotomous tree is, how it is used, and the importance of such a tree.
This study source was downloaded by 100000898182462 from CourseHero.com on 05-06-2025 00:11:25 GMT -05:00
https://www.coursehero.com/file/238247047/Identifying-Bacterial-Infections-Case-Studies-Dichotomous/
