![]() ![]() Meanwhile, the phylogenetic trees of the five individual HKGs also corresponded to that of the concatenated tree, except for recA, which clustered four strains at an independent cluster. Of all 223 Proteus strains collected in the current study, the phylogenetic tree of five concatenated HKGs ( dnaJ, mdh, pyrC, recA and rpoD) divided 223 strains into eleven clusters, which were representative of 11 species of Proteus. In this study, we developed a multilocus sequence analysis (MLSA) approach based on five housekeeping genes (HKGs) to delineate phylogenetic relationships of species within the genus Proteus. The molecular evolutionary characteristics and genetic relationships among Proteus species have not been elucidated to date. They evaluated test results after one week of incubation.Members of the genus Proteus are mostly opportunistic pathogens that cause a variety of infections in humans. Students in our introductory Microbiology laboratory subsequently carried out these experiments, using TSI agar and peptone iron agar as described above, along with the lead acetate strips. Positive tests for the media were indicated by a black precipitate. Cultures were checked, and media and strips were analyzed at 48 hours and at one week. Finally, 3-cm lead acetate strips from Key Scientific were taped to the inside of the tubes, and the tubes were capped. Five trials were performed for each of the three bacteria tested on the different types of media. TSI agar, Kligler iron agar, SIM agar, and peptone iron agar were inoculated with each type of bacteria with a sterile inoculating loop, either streaked on the surface of the slant or as a stab. Tubes were autoclaved and then put on slants for the media to solidify. Then, 3 mL of media was pipetted into 20 test tubes (16 mm × 125 mm), making a total of 80 test tubes for the four different media. Media were covered with aluminum foil and heated until boiling while stirred. Triple sugar iron (TSI) agar, Kligler iron agar, sulfide indole motility (SIM) agar, and peptone iron agar were each mixed in flasks following directions provided by the manufacturer. vulgaris was cultured in a biological safety cabinet under sterile conditions. aerogenes (Ward’s catalog 850033) were grown on nutrient agar slants and incubated at 37☌. vulgaris (Ward’s catalog 851172), and E. Finally, we implemented this process in an introductory microbiology laboratory.Ĭultures of C. Because it is typical in introductory microbiology labs for there to be a week between the time a test is conducted and when it is evaluated, we evaluated these tests over two time points (48 hours and one week). We next determined an optimal detection method, which included two media alternatives (peptone iron agar and triple sugar iron agar) as well as lead acetate strips. vulgaris as a positive control and Enterobacter aerogenes ( 1) as a negative control. We tested Citrobacter freundii ( 1) for this purpose, using P. The first objective of this project was to identify a BSL 1 organism to serve as an alternative to P. ![]() vulgaris has a biosafety level (BSL) 2 classification, and not all introductory microbiological labs are equipped, nor is training provided, to allow students to work with BSL2 organisms. Historically, one organism that has served as a positive control for H 2S production is Proteus vulgaris ( 1, 2). These “unknown” labs are critical for assessing both laboratory skills and critical thinking. Testing bacteria for the production of hydrogen sulfide (H 2S) is a standard laboratory exercise in many introductory microbiology courses and becomes part of the student arsenal of tests that form the “unknown” laboratory in which students have to identify bacteria from a culture given to them by the course instructor. ![]()
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