Practical Microbiology generally refers to the nature of the practical applications of a microbiological field or understanding that can DIRECTLY be applied to reality in consequence. As such, the 'practical side' of microbiology deals with such various concepts as how do we cure viral infections, how do we prevent viral infestations, how do we use technology to examine internal components and structures and so forth.
Above is a picture of a brewery for beer. It is an awesome example of an application of practical research in the field of microbiology. Hops and barley are fermented within a yeast culture. Alcohol is formed and subtle flavours and aromas develop within the process. This tasty treat, well known to humans for thousands of years, is a prime example of applied microbiological research at its finest.
Practical microbiological research never looks at what could be the case 10, 20 years down the road, instead it general focuses on the nature of what is in the now. If it can be seen, touched, or is otherwise tangible, then this particular component (if also microbiological) can easily fit into the category of applied microbiological research. Genetic engineering, once thought to be theoretical in nature, is now a practical understanding, thanks to the mapping out of the gene code.