What is bacterial culture

Bacterial culture

English: bacterial culture

1 definition

Under one Bacterial culture one understands the cultivation of bacteria (e.g. from a smear) in a culture medium for the purpose of reproduction and, if necessary, subsequent determination of the pathogen.

2 Implementation of the creation

2.1 Sampling

First, bacteria are extracted from the site of the infection (e.g. sputum, blood). It is important that the sample is transported in a container that prevents the bacteria from multiplying and dying, and that the sample is examined quickly.

2.2 Creating the culture

The bacteria are then placed on a solid or liquid nutrient medium that contains peptone, serum, a buffer solution and carbon. If the culture is to be examined for specific resistance, an antibiotic is added. If the bacteria are pathogenic to humans, they are incubated at a temperature of 37 ° C.

2.3 Separating the bacteria

Since several bacterial colonies usually grow on a plate, it is essential to separate the colonies for later analysis. This is done, for example, with the three-loop smear.

2.4 Determination of the bacteria

After the bacteria have been separated, they are examined further. This can be done with the naked eye (determination of the growth form) or by Gram staining, specific reactions and investigation of conditions that are necessary for growth (e.g. amino acids).

2.5 antibiogram

The antibiogram is used to find the antibiotic with the best effect. For this purpose, felt pads are soaked with antibiotics and applied to the plate with the bacteria. Resistance can be determined according to the extent of the growth inhibition in the vicinity of the antibiotic platelet.

see also: Growth phases of a bacterial culture