Unknown Lab Report

Topics: Hydrogen sulfide, Gram staining, Agar plate Pages: 7 (2458 words) Published: February 9, 2013
Unknown Lab Report

Unknown Organism #6
Ann Le (Phuoc)
May 6, 2010
Dr. Carrington
Microbiology Lab- MW 12:50

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I. Introduction

My unknown organism #6 is Morganella morganii, which is a gram-negative bacillus rods commonly found in the environment and also in the intestinal tracts of humans, mammals, and reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the 1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an uncommon cause of community-acquired infection and is most often encountered inpostoperative and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate antibiotic therapy; however, its natural resistance to many beta-lactam antibiotics may lead to delays in proper treatment Morganella morganii was previously classified under the genus Proteus as Proteus morganii. (7)

The genus Morganella currently consists of only one species, belongs to the tribe Proteeae of the family Enterobaci Morganella morganii, with two subspecies, morganii and sibonii. (6) In the late 1930s, Morganella morganii was identified as a cause of urinary tract infections and also sepsis, pneumonia, wound infections, musculoskeletal infections, CNS infections, pericarditis, chorioamnionitis, endophthalmitis, empyema, and spontaneous bacterial peritonitis. (7, 8) Anecdotal reports of nosocomial infections Le 2

began to appear in the literature in the 1950s and 1960s. (3) Tucci and Isenberg reported a cluster epidemic of Morganella morganii infections occurring over a 3-month period at a general hospital in 1977and of these infections, 61% were wound infections and 39% were urinary tract infections. (2, 4) The most common source of bacteraemia was postoperative wound infection, and most infections occurred in patients who had received recent therapy with a beta-lactam antibiotic. (6) Other important epidemiological risk factors in these studies included the presence of diabetesmellitus or other serious underlying diseases and advanced age. (3)

II. Material and Methods:

Materials used included:
Gloves, Bunsen burner, flint burner, flint strike, 3 microscope slides, inoculating loop, water bottle, staining tray, crystal-violet, test tube rack, Iodine, Gram’s decolorizer, Safranin, microscope, oil immersion, nutrient agar, potassium hydroxide (KOH), SIM media, Kovac’s reagent, inoculating needle, MRVP broth, Methy red pH indicator, VPA reagents, VPB reagents, empty test tube, mineral oil, MOI, lysine media, and motility medium with TCC. Le 3


First, Dr. Carrington allowed us to pick our organism from a test tube tray. The number of my organism I chose was #6. After picking my organism, the first test I had to do was the gram stain. I had to label everything in order to keep my lab result organized and confusion free. I started out by gathering all the material I needed to do the gram stain test. I transferred a loop full of water on a slide, and then aseptically transferred some of my organism to the slide. I allowed the slide to be fully air dry before I heat-fixed the smears. Heat fixing the slide kills the organism while also helping it retain the dye. After it was heat-fixed, I placed my slide on a staining tray, covering the smear with Crystal-violet for 60 seconds, and then I rinsed it with water. Next I covered the smears with Iodine and allowed that to sit for 60 seconds before rinsing it with water. Then I put about 4 drops of Gram’s decolorizer on top of my smears until all unbound dye was gone. I immediately rinsed it with water to stop the decolorization and covered it with Safranin for another 60 seconds and rinsed it again. I blotted the smear dry and it was red, therefore I concluded this organism was a gram-negative. I than began to examine it under a microscope starting at 50X and gradually moving to 1,000X. I used oil

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immersion so I...
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