Identification of unknown Lab

4/22/2021 Laboratory Simulation

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Student: Manoj

Phases Complete 7 of 7 phases.

Phase Resets Phase 1: 0 Phase 2: 0 Phase 3: 0 Phase 4: 0 Phase 5: 0 Phase 6: 0 Phase 7: 0 Phase 8: 0

CASE REPORT: For the past 10 days, Jackie felt exhausted and lacked her usual stamina. Several times, she ran a fever, which abated when she took acetaminophen. Just walking up the stairs left her short of breath. Since the symptoms seemed to be worsening, she visited her physician. The nurse practitioner noted that her heart murmur, present since childhood, was noticeably louder and much more obvious. She had also developed a petechial rash (purplish streaks) under her fingernails. She had a fever of 38.2°C at the time of the visit. When asked about her activities over the last month, she mentioned that she had a minor outpatient orthopedic surgery to check her previously surgically replaced knee. Suspecting possible bloodstream infection and endocarditis, the medical team ordered blood cultures, which were sent to you in the microbiology lab. Within 24–36 hours later, there was evidence of growth in the culture tubes. Colonies were further isolated on an agar plate for additional investigation and identification.

Case Introduction Questions Based on the information in the case, what organism(s) could or should be suspected to cause this scenario? Select all that apply. Enterococcus faecalis Staphylococcus aureus Staphylococcus epidermidis

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Now that a pure culture has been isolated for you, what would be a good starting procedure to begin classifying your unknown organism?

Gram staining

Collected Lab Data Test Result

Gram staining

Gram (+) cocci in clusters

Catalase test Bubbles were noted on slide, unknown bacteria was concluded to be catalase (+)

Mannitol salt agar test Pink reaction was noted on MSA plate, unknown bacteria grew in high salt and was concluded to be unable to ferment mannitol

Novobiocin test Zone of inhibition was noted on plate, unknown bacteria was concluded to be novobiocin (Sensitive)

Unknown bacterium identification Staphylococcus epidermidis

Completed Dichotomous Key

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