Identification and Diagnosis of Unknown Enteric Bacteria
in an Infected Patient Using an Enteropluritube
BIO 488C - Section J
TA – Jacob Karsten
Enteric bacteria are members of the Enterobacteriaceae family of microorganisms. These gram negative, rod shaped, facultative anaerobes are found in the intestinal tracts of humans and animals. Enteric bacteria can be pathogenic; however, they are also a normal part of human bacterial flora and are therefore found in both healthy and infected hosts. This is why fecal matter found in contaminated water and food supplies as well as public recreational areas such as beaches can cause serious intestinal tract infections and urinary tract infections, among other diseases (Todar 2012). Escherichia coli is a major microorganism belonging to this family of bacteria and is an example of how enteric bacteria are important to medical research (Todar 2012). E. coli is used to identify fecal pollution, and is often used in experiments due to its naturally occurring nature and ability to grow quickly and easily in a laboratory environment (Todar 2012). This experiment will attempt to identify bacteria isolated from an infected patient. The bacterium is thought to belong to the Enterobacteriaceae family due to the characteristics of the patient’s illness. The patient in question is a four-year-old female toddler who became infected at a daycare. It is believed that the illness came about via direct contact. The child’s caretaker likely neglected to properly wash their hands after handling the diaper of another child and then came into contact with the patient. The toddler consequently suffered from a fever and diarrhea containing mucus. In order to identify the enteric bacteria causing this patient’s fever and diarrhea, the gram negative and oxidase negative organism will be inoculated on an EnteroPluri-Test. The EnteroPluri-Test is a tube with 12 sections containing different culture media, each pertaining to a different biochemical test. Fifteen total tests can be performed on the bacteria using this tube and once the results are interpreted, the enteric bacteria causing the patient’s illness will be identified (Liofilchem 2015). Materials and Methods
This experiment was performed over the span of two days. The first day, materials included 1 Enteropluritube and a sample culture of the unknown Enterobacteriaceae. In order to inoculate the tube, both caps were first removed from either end of the tube. One end of the tube will reveal a short exposed metal tip of a wire that runs through the Enteropluritube. This metal inoculating tip was used to gather one isolated colony of unknown enteric bacteria by touching the end to a colony. The opposite end (the side closest to the glucose test) of the tube was then twisted and pulled out, gradually twisting the wire through the tube, taking care not to pull it out entirely. The wire was then reinserted the same way it was pulled out until the tip came back out the other end. A notch became visible at this end allowing the tip to be snapped off. The snapped of tip was then used to puncture holes in the plastic film on the tube’s side covering the last eight tests (adonitol, lactose, arabinose, sorbitol, Voges-Proskauer, dulcitol/PA, urea, and citrate). Both caps were then replaced, and the tube was incubated for 24 hours at 37 °C (Hébert and Leid and Shand 2015). The second day of the experiment was spent interpreting the results of the Enteropluritube. Materials required were the inoculated tube from the day before, an Enteropluritube results sheet, Enteropluritube Computer Coding Identification System, Kovac’s reagent, and Voges-Proskauer reagents (20% KOH and 5% alpha-naphthol). The Indole test was performed by melting a hole in the plastic around the H2S/Indole section of the tube with a hot inoculating needle. One to two drops of Kovac’s Reagent were then inserted through the...
Cited: Hébert S, Leid J, Shand R. 2015. Medical Microbiology Lab Manual. Flagstaff (AZ): Northern Arizona University Publishing 20-22 pp.
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Liofilchem – Microbiology Products. 2015. EnteroPluri – Test Codebook. Rosetto degli Abruzzi (IT): Liofilchem I-IV pp.
Todar, Kenneth . 2008. Bacterial Pathogens of Humans [Internet]. Madison(WI):Online Textbook of Bacteriology; [2012, cited 2015 Feb 16] . Available from: http://textbookofbacteriology.net/medical_3.html
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