Uknown Microorganism Lab Report

1074 Words5 Pages
31 October 2011
Identification and observations of Citrobacter Freundii
Introduction
Citrobacter Freundii is a species of bacteria that can be potentially harmful to humans. It is known to cause meningitis by protruding into the brain and replicating itself (1). The Citrobacter species has also been found as a cause of some urinary tract infections, diarrhea, and even gastrointestinal diseases and symptoms (3). C. Freundii can be located in a wide variety of soils and water (3). Lastly, it is also the cause of many nosocomial infections due to its presence in water (1).
Identifying C. Freundii holds importance in order to determine infection in gastrointestinal and urinary tracts and in the brain. These infections will often be
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Table 3 shows Gram stain results that indicated C. Freundii as a gram negative bacterium in rod shapes scattered in singles and some in pairs. Each gram stain produced the same results. The Bartholomew and Mittwer method of endospore staining indicated that C. Freundii tested negative for endospore formation. Table 4 shows the biochemical test results of the unknown and the official test results for comparison. The Kirby-Bauer antibiotic tests indicated that the unknown is susceptible to chloramphenicol and ampicillin and resistant to penicillin G and tetracycline. The disinfectant sensitivity tests indicated that C. Freundii is resistant to all four of the disinfectants.
Discussion
The biochemical tests, the Gram stain, the Bartholomew and Mittwer’s stain, the microscopic and macroscopic observations, and chemical sensitivity tests helped to identify the unknown bacteria as Citrobacter Freundii. Each biochemical test result maintained consistency with the

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