The test was performed as a standard culture procedure with gram staining on a selective medium (MAC) to interpret the shape and species of microorganisms. The selective medium was necessary for a more accurate and detailed identification based on the parameters of the medium and the presence of lactose. The test revealed the formation of rods and several cysts; the presence of lactose was not detected, and the Gram stain was negative. It allowed to rule out attributing the species to enterobacteria and exclude staphylococci.
The KIA test was performed to determine the bacteria’s hydrogen sulfide and evaluate the ability to utilize carbohydrates. The test observed the formation of a black beveled precipitate and yellow over the cracked agar above. The black deposit indicates the formation of hydrogen sulfide and an alkaline residue. Consequently, the bacteria can produce hydrogen sulfide and not ferment lactose, as confirmed by seeding on MAC. Thus, this allowed assigning the bacteria to some salmonellae and citrobacteria and excluding shigellae and pseudomonas completely.
The SIM test was performed to check the body’s ability to move and perform several functions. A biphasic separation was observed during the test: a black precipitate and a yellow supernatant were observed in the test tube. The black phase signaled the presence of hydrogen sulfide, and the yellow phase signaled the absence of indole; moreover, they are most likely mobile. The analyzed bacteria are not capable of processing indole but produce H2S. Consequently, the bacteria cannot be assigned to Escherichia coli but can be set to shigellae and salmonellae.
The urease test is used to determine the ability of a microorganism to produce acid when urea is added to the agar. No change in coloration was observed in the test, which would indicate a difference in the hydrogen index. Consequently, the test tube organism is incapable of breaking down urea and forming ammonia. Thus, potential microorganism species can include Escherichiae, Shigellae, and Salmonellae, but not Brucellae.
The indole test, triptone, allows the presence of indole in the medium to be determined by its ability to break down tryptophan. During the trial, it was found that the color (yellow) was preserved, and no pink or red ring appeared in the upper phase. Consequently, these observations mean that the microorganism cannot convert tryptophan and produce indole. Thus, most Klebsiellae and some Salmonella are likely candidates but can never be Escherichia coli or Flavinobacteria.
The PR Lactose test determines the body’s ability to utilize various carbohydrates (in this case, lactose). The test showed yellow staining and retention of the tube in the medium. Such data could mean that the microorganism can convert carbohydrates – lactose – and lower the test tube’s pH level. Consequently, the potential microorganisms are gram-negative species that recycle carbohydrates. These can include Enterobacteriaceae (e.g., Shigella) but not Pseudomonas species.
The present microorganism has been linked to clinical case #4 about seizure fixation. The unknown microorganism is a Gram-negative organism with an additional lipid wall – contributing to subfebrile fever. In addition, tests indicate the ability to move and produce hydrogen sulfide, which alters the gut microbiota and can lead to seizures (1, 2). A biphasic SIM separation and a negative indole test indicate that the bacterium belongs to Enterobacteriaceae. The presence of Enterobacteriaceae, which alter the state of the intestinal microbiota and consequently cause severe nervous disorders, can most likely be judged. They produce various toxins, such as lipopolysaccharide endotoxin (1). After the bacteria die, this substance is released and enters the body, causing a rise in temperature and a drop in blood pressure.
References
Dahlin, M., & Prast-Nielsen, S. (2019). The gut microbiome and epilepsy. EBioMedicine, 44, 741–746. Web.
Lum, G. R., Olson, C. A., & Hsiao, E. Y. (2020). Emerging roles for the intestinal microbiome in epilepsy. Neurobiology of Disease, 135. Web.