ExperimentalIdentification of an unknown Bacterial strain.
Alarge number of communicable diseases in a given environment arecaused by microbes which include bacteria, protozoan, fungi andviruses amongst others. Medical practitioners can only be efficientand effective in their diagnostic work if they can easily identifysuch microbes by performing standard tests and other contemporarymicrobiological tests before undertaking any treatment procedures. Identification of the organism involves placing it in a certain groupdue to its characteristics. It is important that correctidentification of microbes and in this case, bacterium be donerepeatedly to be sure of the identity of the unknown species.
Thereare many Microbiological, and more specifically Bacteriological testsand experiments that can be done to identify microbes. These includeGram reaction tests named after Gram who developed it which groupsthe bacteria into Gram positive or Gram negative categories. Otheridentification techniques are morphological, serological, proteinanalysis based, comparison of nucleotide sequencing, typing just tomention a few [ CITATION Abe14 l 1033 ]. All these tests are developed so as to improve identification andalso arrive at correct and precise identities.
Inthis report, we have performed some experiments to identify anunknown strain of bacteria from a specimen in the laboratorypresented to the group. The experiments were performed under normaland standard laboratory conditions.
Standardmaterials were used as in common experiments to perform morphologicaltests, Gram reaction test, Catalase test, beta hemolytic test, growthand fermentation of Mannitol Salt Agar (MSA), coagulant test,sensitivity test to novobiocin, bile esculin test and sodium chloridetolerance test. Standard procedures were followed in the experimentwith correct test concentrations of the solutions involved.
Resultsfrom the experiments performed indicate that:-
The bacteria have oval shape and live in colonies or clusters.
The gram test performed gave a change in cell wall coloration to purple color showing that the bacteria are gram positive [ CITATION Sci14 l 1033 ].
Catalase test was conducted and it showed positive results.
Coagulant test was positive
The Beta hemolytic was conducted and it was negative for streptococcus.
Growth and fermentation on mannitol salt agar was not observed and the yellow color was not seen.
Sodium chloride broth test was negative showing that the species were not salt tolerant.
The specimen was exposed to novobiocin and they were sensitive to novobiocin.
Themorphological descriptions observed suggest the coccigroup of bacteria such as Enterococcusand Staphylococcusand Streptococcusbacteria. The catalase test conducted was positive confirming thatthe bacteria are from the coccigroup. The Gram reaction test shows that they are also Gram positiveand therefore we need to be sure of the type of bacteria we aredealing with. The mannitol salt agar did not show growth andfermentation and the expected yellow color was not observed from thistest. Therefore, the Enterococcusgroup can be eliminated leaving the Staphylococcusgroup to be fully identified and confirmed. However, we need to besure of the Staphylococcusand therefore the other tests are done to confirm the group. Thesodium chloride broth was not detected, and yet the color did notturn yellow confirming that the bacteria do not belong to theEnterococcusgroup.
Thenovobiocin test was positive confirming that the bacteria belong tothe Staphylococcusgroup. Novobiocins are antibiotics that are anti staphylococcal thusmaking them active against Staphylococcusbacteria [ CITATION Kat10 l 1033 ].
Toget further into the group, the coagulase test done was positive andthis confirmed that the bacteria in question must be Staphylococcusaureus. The coagulant test is a confirmatory test for Staphylococcusaureus. The figure below shows the characteristic Gram positive purple colorcluster of Staphylococcusaureus[ CITATION Sci14 l 1033 ]
Source:Science Prof online.
Thebeta hemolytic test was negative and therefore eliminating theStreptococcusgroup of bacteria. This was also confirmed by the negative bileesculin test which also eliminates Streptococcusand Enterococcusgroups since it showed that the bacterium is not a group D.
Fromthe results of the experiments conducted in this report, we canconfirm the identity of the bacterium as Staphylococcusaureus.
Staphylococcusaureusbacterium is the leading of all staphylococcus based infections inhumans, according to Mayo Clinic [ CITATION Nna10 l 1033 ]. Thebacterium causes most common skin infections such as impetigo andskin inflammations. It also frequently affects the human respiratorytract causing infections of the tract.
Foodspoisoned by Staphylococcusaureusresult in symptoms such as diarrhea, nausea, vomiting anddehydration. It also has other adverse effects which have not beenmentioned in this report.
Identificationof unknown microbes such as bacteria must be done correctly andaccurately. Incorrect identification of the species can bring aboutwrong diagnostics hence wrong treatment by medical practitioners andwrong control measures undertaken and these would have adverseeffects on the patients involved. Therefore precise and relevantexperiments must be conducted in such identifications.
Abedon, S. T. (2014). Identification of Bacteria. Retrieved May 8, 2014, from Mansfield: http://www.mansfield.ohio-state.edu/-sabedon/biol3010.htm
Kateete, D. P. (2010). identification of staphylococcus aureus. animal and clinical microbiology and antimicrobiols .
Nnama, H. (2010). Effects of Staphylococcus aureus. Retrieved May 8, 2014, from Livestrong website: http://www.livestrong.com/article/180196-effects-of-Staphylococcus-aureus
online, S. p. (2014). Gram stain test for Gram+, Gram- bacteria. Retrieved may 8, 2014, from science prof online website: http://www.scienceprofonline.org/microbiology/gram_stain….bacteria id.html