Microbiology : Bacteria - Lab Report Example

Paul Ehrlich discovered the first antibiotic by using dyes to ‘stain’ the bacterium Treponema pallidum, which caused syphilis, and he too was awarded the Nobel Prize in 1908 for his contribution to immunology. A significant discovery was made in the year 1977 when Carl Woese determined that archaea had different evolution traits than bacteria. The branch of Science which specifically involves the study of Bacteria is known as Bacteriology which is a branch of Microbiology. Bacteria are present in almost every nook and corner of the earth ranging from hot volcanic regions to ice cold polar caps.

There are approximately 5?1030 species of bacteria found in earth. In fact, it has been found that the number of bacteria found in the human body exceeds the total number of cells. A number of bacteria causes disease and is known as pathogenic bacteria. Some of the diseases caused by bacteria are cholera, tuberculosis, syphilis, leprosy etc. The use of antibiotics is common as cure for disease caused by bacteria. Not all bacteria are pathogenic. Bacteria are useful in bio-degradation and are used in processes like solid waste management and sewage treatment.

It also finds application in food industry (production of cheese and yoghurt through fermentation) and in biotechnology and pharmaceutical industry. Figure 1: Types of Bacteria It therefore becomes very essential for us to classify the bacteria and determine its characteristics. The most popular technique for the identification of bacteria is the Gram Stain Process which is the method adopted in this experiment. The origin of Gram Stain Process dates back to 1844 and was given by the Danish physician Hans Christian Gram.

FLOWCHART OF IDENTIFICATION PROCESS RESULTS & INFERENCES Gram stain: negative This means that the bacterium belongs to the genera Veillonella or Acidaminococcus or Megasphaera. In Cowan and Steel’s Manual for the Identification of Medical Bacteria, there are 39 species of bacteria that fall under this category. Some chief ones being: 1) Alcaligenes 2) Pseudomonas 3) Klebsiella 4) Shigella 5) Salmonella 6) Escherichia 7) Aeromonas 8) Chromobacterium 9) Neisseria 10) Other enteric genera O2 requirement: facultative anaerobe Lactose: + growth + acid + gas Dextrose: + growth weak +acid - gas Sucrose: + growth +acid - gas Nitrate reduction: positive before zinc (nitrate reductase positive), Catalase: Positive, Cytochrome Oxidase: negative EMB: negative growth Due to the afore-mentioned results one can infer that the species is a type of lactose non-fermenter enterobacteria.

Spore stain: vegetative cocci This result zeroes down our species to Neisseria which is completely different from enterobacteria which are rod-shaped. MSA: positive growth – manitol The enterobacteria are manitol fermenting. Therefore, it means that it can be a type of lactose-non-fermenting enterobacteria. Blood hemolysis: weak beta. Amylase Lipase Protease and Gelatinase all negative, TSI slant: acid slant alkaline but H2S negative IMViC: negative Methyl red: negative Citrate utilization: negative Urease Utilization: negative The bacteria does not produce H2S and has a negative IMViC test which means that the species of bacterium is probably E.

Coli (inactive) ESCHERICHIA COLI (INACTIVE) E. Coli (inactive) is a Gram-negative, rod-shaped bacteria(bacilli) which is found in the intestines of mammals. E. Coli (inactive) is harmless and not pathogenic unlike its namesake and is therefore called as inactive.