Write a 8 pages paper on district laboratory practice in tropical countries. After successful identification, a sensitivity test follows to determine the most effective antibiotic. This paper will highlight the micro biological principles that govern culture and sensitivity. Different microorganisms thrive in different systems of the body due to the varying environmental conditions. Microbiologists have described a vast range of microorganisms that thrive in the digestive tract, urinary tract, and blood (Baker, & Swain, 2002). Moreover, more elaborate studies have sought to establish the microorganisms that are responsible for causing different infections. Other critical studies focus on describing the conditions under which different organisms thrive. The understanding of these basic fundamental aspects in microbiology led to the development of cultures. The main purpose of culture is to foster the growth and multiplication of the microbes in a sample. After intensive growth in the appropriate media, identification and analysis follow. Bacterial Classifications The microbiologist should have vast knowledge concerning the classification of bacteria. Gram’s classification of bacteria into the renowned categories of gram positive and gram negative strains remained very essential. Moreover, depending on the need for oxygen as a growth factor is an additional criterion for classifying bacteria. Some are aerobic and oxygen must be present for any form of growth to occur while others do not need it. A good mastery of the bacterial classification criterion is critical in choosing the most appropriate culture conditions (Baker, & Swain, 2002). Media Composition and Classification Media denotes any substance prepared for the growth, transport and storage of microbes. Consistency of media varies from liquid to solid. The composition of media varies depending on the microbe of interest (Rao, 2010). The media contains all the necessary growth requirements. Microorganisms have different metabolic pathways. The basic nutritional requirements include a carbon source, nitrogen source, salts, and minerals in different quantities. However, different species of bacteria may require additional nutritional elements, a factor that helps in identification of microbes (Wilson, & Walker, 2010). Liquid media is critical for transport of microbes. Solid media contains a percentage of agars as a solidifying agent. Media preparation is a critical step prior to culturing any microbes. The quality of the media prepared determines whether growth of pure cultures can occur. Therefore, a microbiologist thrives to operate in sterile conditions as well as sterilizing all equipment and materials before use. Sterility is essential because contamination will translate to growth of microbes that are not present in the sample. When the purpose of a culture is obtaining a pure culture for diagnostic analysis, then contamination hinders any accuracy in the identification compelling the researcher to start all over again (Wilson, & Walker, 2010). There are different classifications of bacteria according to their nutritional characteristics. A clear understanding of this classification is very crucial because it serves as a guideline in the choice of the most appropriate media. Autotrophs are microbes that have the capacity to utilize inorganic carbon dioxide in the synthesis of macromolecules (Widdel, 2010).