by Darian Peters

Created on: December 09, 2008

Bacteriology is the study of bacteria, microorganisms with a wide variety of effects, both positive ones, such as helping human digestion, and negative ones, such as causing diseases. Bacteriology can be considered a sub-discipline of microbiology and was founded by Ferdinand Cohn in the 19th Century. It was him that would be the first to provide a taxonomy for bacteria. Present day bacteriology is a wide-ranging field which reflects the wide range of habitats and functions of bacteria.

Bacteria are procaryotic microorganisms, just a few micrometers long, that are usually found unicellularly, but much more rarely are to be found in multicellular forms. They can come in a variety of shapes and the name of a bacterium will often give a clue as to the shape. Cocci (as in the infamous streptococci) are spherical, for example, whilst baccili are rod-shaped, spirilla are helical, and vibrios are curved and rod-like.

Bacteriologists have traditionally aimed to identify bacteria by morphology and through biochemical testing. More recently, molecular studies, such as the use of probes, are increasingly being used. In this case a nucleic acid probe can be used to identify a microorganism that may be present in a food stuff, for example, by detecting the presence of an indicative nucleic acid sequence.

Bacteria can survive in a wide variety of environments arguably encompassing all available habitats, from the soil, where some varieties have functions as nitrifying or nitrogen fixing agents, to others that live in the water, whilst others are found in the air. They can exist inside other creatures such as plants and animals, and they can even in exist in the extreme habitats of radioactive waste, acidic hot springs, and deep in the crust of the Earth. So the scope of bacteriology is a very wide one, with bacteriologists requiring different knowledge, approaches, and techniques as are appropriate in each case.

This variety of areas of study is further enhanced when you consider the variety of possible functions of bacteria in their chosen environment. For example, they can function as symbionts (living to mutual benefit with another organism), parasites (taking benefit from another organism), and pathogens (harming another organism through disease).

The variety of topics for bacteriology to investigate is enriched even more by the various reproductive possibilities of bacteria. Although they reproduce asexually they can modify their genetic information in a variety of ways. These include conjugation, transformation, transduction, mutation, recombination, and plasmid acquisition. All in all bacteria are a highly wide-ranging type of organism and provide many and diverse challenges to researchers in the field of bacteriology.

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