Exam 10: Identifying and Classifying Microorganisms

A probe is a single-stranded piece of nucleic acid labeled with a detectable marker, used to locate a unique nucleotide sequence that identifies a particular microbial species.

A male patient comes to the clinic where you work complaining of urethral discharge and pain on urination. He has recently had unprotected sex with someone he met at a party. You take a sample of the urethral discharge for analysis. -You tell the patient that his sample contains white blood cells in which Gram-negative diplococci can be detected. Your patient asks how you obtained this result and you tell him you

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Strains of an organism can always reliably be identified using RFLPs (restriction fragment length polymorphisms).

Phenotypically identical bacteria

Which of the rRNA molecules has proven the most useful in taxonomy/identification?

You are working in a clinical lab. Two E. coli samples are sent to you for analysis and you are asked to determined whether they are the same strain. You perform an antibiogram and find that the two samples exhibit the same sensitivity to the antibiotics you use in the procedure. This indicates

You patient tells you he has heard that N. gonorrhoeae is increasingly difficult to treat because of resistance to antibiotics. He asks whether it is possible to determine which antibiotics will be affective in treating his infection. You tell him that ________ indicate antibiotic susceptibility.

Gram-positive encapsulated diplococci found in sputum are likely

APIᵀᴹ, Enterotubeᵀᴹ, and Vitekᵀᴹ are all

The point at which two organisms diverged from a common ancestor

The relatedness of organisms determined by counting common characteristics

Why are molecular methods particularly useful for identification of microbes that are difficult to grow?

You isolate a prokaryote. After performing analysis on the organism, you cannot find a description matching that of your organism in the reference text Bergey's Manual of Systematic Bacteriology. This suggests that you have likely isolated a new organism.

You are sent three clinical samples and are asked to determine whether they are the same strain. You perform standard identification techniques but cannot come to a conclusion. You decide to do an RFLP test. You digest the genomes of the organisms with the same restriction enzyme and run a gel. Each organism yields 5 bands on the gel, of the following sizes:  Organism A: 3 kb, 7 kb, 11 kb; 14 kb, 21 kb Organism B: 3 kb, 7 kb, 2 kb, 8 kb, 11 kb Organism C: 11 kb, 3 kb, 14 kb, 7 kb; 21 kb What conclusion(s) can you make from this result?

The more closely related two organisms are,

rRNA sequence comparisons are useful for determining evolutionary relationships.

The name Lactococcus (Streptococcus) lactis

In E. coli O157:H7, the O157:H7 refers to the

The basic taxonomic unit in the classification scheme of plants and animals is