Microbiology for Detection of Unknown Microorganism-myassignmenthelp

Question: Discuss about theMicrobiology for Detection of Unknown Microorganism. Answer: Results The microorganism is Enterobacter aerogenes. Gram-staining revealed that the organism is Gram-negative and is rod shaped or bacillus. It showed growth on MacConkey and EMB agar. It showed positive citrate test, glucose and lactose fermentation. It gave negative results for hydrogen sulphide production as no black precipitate was observed. It showed weak urea hydrolysis, no gelatin hydrolysis. It showed positive motility as growth was observed away from slab. The organism showed positive results for ornithine, lysine, sugar aldehyde, sorbitol, o-nitrophenyl -D-galactoside, p-nitrophenyl -D-glucoside, p-nitrophenyl -D-xyloside, p-nitrophenyl n-acetyl--D-glucosaminide, malonate, -Glutamyl napthylamide and adonitol tests. Table 1. Phenotypic and Biochemical tests Unknown organism: Enterobacter aerogenes Test Observation/Result of test Interpretation/Meaning Gram Stain Colour: Pink/Red GRAM - Cell length (mm) 0.1 mm Not Required Cell shape arrangement Rod shaped Not required Colonial characteristics on TSA Whole colony shape: Irregular Edge/margin: undulate Surface: glistening umbonate Colour: Translucent white Not required Growth on selective medium MacConkey: + growth EMB: + growth PEA: - Growth GRAM - Oxygen requirement Growth in FTM: Growth greatest at surface Growth in GasPak: little bit of growth Facultative aerobe Citrate Test Positive Green-blue Indole (SIM) No red - Voges-Proskauer Test Yellow - Methyl Red Test Yellow/orange Negative results Glucose fermentation (KIA after 24 hours) Color change, observed growth on surface + Lactose fermentation (KIA after 24 hours) The medium has been lifted due to gas produced. + H2S (KIA or SIM after 48 hours) No black precipitate. No sulfur reduction Negative results Urea hydrolysis Slightly pink W +, weak positive Gelatin hydrolysis Slightly movement, still gelatin like consistency Negative results Motility Growth observed away from slab + Discussion All the microorganisms were Gram-positive rods. However, the microorganisms cannot be Escherichia coli as it shows positive results for indole and methyl red test. E. coli shows Voges-Proskauer and citrate test negative (Odonkor Ampofo, 2013). But, the organism shows indole and methyl red negative results, while citrate test is positive. Proteus mirabilis and Citrobacter freundii are known to show positive methyl red tests. The organism shows positive lactose fermentation. P. mirabilis and Serratia marcescens give negative results for lactose fermentation, while C. freundii, E. coli and Enterobacter aerogenes show positive lactose fermentation tests. C. freundii and P. mirabilis shows positive for hydrogen sulphide production, while the organism shows negative for hydrogen sulphide production (Kumar, Tyagi Gupta, 2012). Thus, the organism is not P. mirabilis and C. freundii. S. marcescens shows positive results for gelatin hydrolysis, but the organism gave negative results for gela tin hydrolysis. Thus, the organism is not S. marcescens. P. mirabilis and C. freundii gives negative for adonitol tests but the organism showed positive for adonitol tests. On the otherhand, S. marcescens gives negative for malonate test, but the organism showed positive results for malonate test. Thus, it can be concluded that the organism is E. aerogenes. However, the errors present is that the Voges-Proskauer test should have been positive. The urea hydrolysis test should be negative but here it was weak positive. Reference List Kumar, D., Tyagi, N., Gupta, A. B. (2012). Sensitivity analysis of field test kits for rapid assessment of bacteriological quality of water.Journal of Water Supply: Research and Technology-Aqua,61(5), 283-290. Odonkor, S. T., Ampofo, J. K. (2013). Escherichia coli as an indicator of bacteriological quality of water: an overview.Microbiology research,4(1).