Posted: May 19th, 2015

Unknown Mixture

Paper, Order, or Assignment Requirements

Introduction
The introduction should not be too long, but should supply sufficient background information to put the experiment in perspective and for the reader to evaluate the results. For example, the introduction should explain briefly the principles of identification schemes, approaches to isolation and identification of an organism from an unknown mixture and applications of these principles to diagnostic microbiology. This leads into the aims of the experiment, which are presented at the end of the introduction. 
Write a short paragraph to introduce each topic, with a final sentence giving the aims of the exercise. Then follow with your aim. The introduction is written in the present tense (Staphylococci are common causes of skin infections…”. 
The unknown mixture was:
H1= Shigella Flexneri
H2= Staphylococcus saprophyticus
H3= Clostridium  Perfringens

Results
Use the results recorded 
Results are written in the past tense (Organism A produced yellow colonies on….”. The only exception is that the present tense is used if you are referring to a table, for example, “The biochemical reactions for organism A are presented in Table 1.” The most appropriate method of analysing results and presenting the data requires careful thought. The results should be correctly and faithfully reported, but this does not mean that all raw data should be included. However the results of all relevant tests should be included. Results should be reported so that the sequence of tests 
The major interpretation of results is reserved for the discussion section. The results should not contain a repetition of information already presented under “Introduction” or “Materials and Methods”. 

For H1: Shigella Flexneri
Biochemical Test
Gram stain =gram negative rod shaped 
Oxidase = Negative
Motility = Negative
Gas from glucose = Negative
Acid from Mannitol = Positive
Galactosidase ONPG = Negative
Citrate Utilization = Negative
H2S Production (TSI/Kligler) = Negative

For H2: Staphylococcus saprophyticus
Biochemical Test
Gram stain =gram positive cocci 

Catalase = Positive
Slide coagulase = Negative
Tube coagulase = Negative
PYR = Negative
Urease = Positive
Novobiocin 10mm Resistants
Polymyxin B 12mm susceptible

For H3: Clostridium Perfringens
Biochemical Test
Gram stain =gram negative rod shaped 
Motility = Negative
Meat Digestion =Negative
Litmus milk =Acid, Gas, and Coagulation of casein (AGC)
EYA-Lecithinase= Positive

Discussion

The discussion section should be a discussion of the results obtained. The discussion is written in the past tense, except when mentioning a known fact, e.g. Clostridium sporogenes is a gram-positive bacillus, however, we found (or it was found – this is past passive tense) that some cells stained …… For these exercises the discussion can be short. If any unusual or unexpected results are obtained, it is important to attempt to explain them and to suggest further work the may be required to answer any questions that arose from the work. This includes acknowledging any errors in the performance of the experiment and suggesting improvements to the experiment. The discussion section should not contain a repetition of material already presented in the results section or of the introduction. 

References 
6 references, Vancouver style please use endnotes, Very important to number the references in the essay. 

Questions
In a separate section headed “questions”, at the end of your report answer the following questions about each of the bacteria you identified:
1- Shigella Flexneri:
a- Does, the organism usually behave as a pathogen, commensal or environmental organism?
b- If a pathogen, list up to three infections caused.
c- If normally a commensal, what is the natural habitat and what opportunistic infections can it cause?
2- Staphylococcus saprophyticus:
a- Does, the organism usually behave as a pathogen, commensal or environmental organism?
b- If a pathogen, list up to three infections caused.
c- If normally a commensal, what is the natural habitat and what opportunistic infections can it cause?
3- Clostridium Perfringens:
a- Does, the organism usually behave as a pathogen, commensal or environmental organism?
b- If a pathogen, list up to three infections caused.
c- If normally a commensal, what is the natural habitat and what opportunistic infections can it cause?