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Either my gram-stain slides were bad or the microscopes I chose for viewing were not good. No bacteria were found under the microscope. } Prepare another gram stain of the unknown bacteria. {Gram-positive, cuscus shaped bacteria were observed under the microscope. Also noted, the slide may have been inadvertently contaminated during the gram stain process by another person in the laboratory. } [l do think that the gram-stain result is surprising – the two gram-positive Cisco species we’ve been given form medium-sized, round, uniformly colored colonies on TTS plates.

When I say the borders of the bacterial colonies are irregular, I mean that both the shape is irregular and the consistency of the borders is not like the center of the colony. Associate this type of appearance with rod-shaped bacteria in general, whether gram-positive or gram-negative. ] Perform catalane test. {Catalane test is positive. } Inoculate test tubes prepared with the following mediums – Triple Sugar Iron agar slant (ITS slant), Bile Esculents Agar slant (BEA tube), a methyl-red Vogues- Prosperous tube (MR..-UP tube) and a Areas tube. Incubate the inoculated tubes, to be read at the following lab session.

Observe results of tests inoculated during the last session [Note: I used the wrong setting on my digital camera to take these pictures, so they are all blurry! Also, thinking about the results from the last session, I am thinking that my bacteria is Staphylococcus saprophytic – gram-positive Cisco, positive catalane. I did my research, and at this point I am expecting a positive areas result and a negative BEA result. ] Negative result for areas {The broth in this tube would have been pink if the areas test was positive. So, that leaves Intercourse fiscals, which would have a positive BEA result. Negative BEA result This is a negative result for the BEA test. So it’s not Intercourse fiscals. And I am out of gram-positive Cisco species from my list of possible bacteria. I need to start over from the gram-staining step. But first I note the results from the other two tests. } IOWA result for ITS slant {This slant looks like the result for Shillelagh. [A helpful Alabama saw my tube and said, “l know what you have.. Your tube looks like a rainbow! ” I shook my head, telling her I knew what she was thinking, but no, it wasn’t that. When I said that, was still confused by all these conflicting results!

I really thought the ITS slant exult was just rubbish at that point. ] The result of this test definitely rules out Protest vulgarism and Salmonella Psychiatrist? ] because there is no Hydrogen sulfide in the tube, which would be indicated by the presence of a black color in the medium. } Positive MR..-UP result {10 drops of methyl red reagent were added to this tube, then gently mixed. Red or pink color indicates a positive test. There is only one bacteria on the list for which we saw a positive result in our regular lab sessions for MR..-UP – Escherichia coli. } Prepare gram stain slide of bacteria. This time, gram-negative rods are observed. Was what I saw last time contamination from skin bacteria, or am I seeing what I want to see? The majority of the bacteria on this slide were pink – gram-negative. I’m going with that! } Perform catalane test again to confirm catalane positive result. {The catalane test can be tricky, though it is a simple test to perform. False-positive test results are common. I am redoing this test because most of the remaining bacteria species are catalane-negative ” except for Escherichia coli, which I am sure is catalane positive. Some of the others am unsure of, and will need to research later.

A repeat test confirms that the unknown is catalane-positive. } Inoculate the following mediums with the unknown bacteria: Sulfide Indolent Motility tube (SIMI tube), a second MR..- UP tube, a lactose broth tube (with Durham tube), and a McCracken agar plate. [Yes, at this point think I have E. Coli. ] Incubate and observe results at next lab session. [Identification is due at the end of the next lab session. ] TTS plate with original sample is discarded. [After thinking about it and researching at home, am sure I have Shillelagh (flexible or sooner). In fact I am sad I did all the extra work – I should have known.

By the way, I did a second MRS.. Tube because, as we discovered in an earlier lab, there may have been a concentration problem with our methyl-red reagent that would give a false-positive result. I plan to add less reagent to the tube in this session. ] Results of tests inoculated in the last lab session: Negative lactose fermentation test {A positive test would have a color change to yellow, and the Durham tube would probably have a gas bubble in it. This result rules out Escherichia coli and Entertainer arrogates. } Negative result for McCracken agar {Positive result – colonies grown on the medium would have turned red.

This test also rules out Escherichia coli and Entertainer arrogates. } Negative Sulfide production {No Hydrogen sulfide, so it is definitely not Entertainer arrogates. This test also probably proves that the unknown is not Salmonella [typographic? ] or Protest vulgarism, but based upon experience in this lab throughout the semester am not sure if this test is diagnostic for these species. } Negative indolent test {This is the SIMI tube shown above with 5 drops of Kava’s reagent added to it. If this test had been positive, there would have been a red or pink ring visible on top of the medium. There is no color, so it is negative.

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