Introduction The isolation and identification of microorganism such as bacteria constitute a systematic process that applies physical and chemical attributes in the laboratory environment. Given that microorganisms are diverse and ubiquitous, the isolation of a pathogenic species that caused the death of Drosophila melanogaster (fruit flies) is a critical step in the study. The isolation involves separating a particular strain or species of bacteria from diverse microorganisms that live in a certain environment (Madigan, Martinko, Bender, Buckley, & Stahl, 2015). Surface plating, selective media, incubation, and inoculation are common laboratory approaches used in the isolation of bacteria (Medina et al., 2017). Surface plating involves a series of streaks on plated media until pure colonies of bacteria emerge. Selective media allows the isolation of bacteria using nutrients that enhance or antibiotics that suppress the growth of a particular strain. Incubation is an approach that uses atmospheric surroundings, such as temperature, aerobic condition, anaerobic state, and carbon dioxide concentration, in selecting bacteria that survive in a stringent environment. Inoculation of bacteria into appropriate host permits selection for microorganisms survive under specific physiological conditions. Phenotypic characteristics of colonies, such as shape, size, elevation, surface texture, edge patterns, colour, structure, the degree of growth, and the nature of spread, improve the isolation of pure colonies in the growth media. Thus, a combination of these approaches has enhanced the isolation of bacteria. Following the isolation of pure colonies is the identification to establish where bacteria fall into the classification scheme. The common laboratory techniques employed in the identification of bacteria are the morphology of colonies and cells, biochemical reactions, physiological mechanisms, and genetic characteristics. The morphology of colonies includes size, shape, surface texture, colour, motility, and edge patterns among other features (Teeseling, Pedro, & Cava, 2017). Additionally, the morphology of cells can classify bacteria into five groups, namely, rod-shaped (bacilli), spherical-shaped (cocci), comma-shaped (vibrio), corkscrew-shaped (spirochaetes), and spiral-shaped (spirilla) (Constantino, Jabbarzadeh, Fu, & Bansil, 2016). In this case, the unknown bacterium was a bacillus for its morphology depicted it as rod-shaped. Biochemical methods identify the physiological features of bacteria. These methods are staining, nitrate test, indole test, methyl red test, citrate test, catalase test, motility agar, ONPG test, ornithine decarboxylase test, xylose fermentation test, and mannitol test (Madigan et al., 2015). In this view, the experiment applied these approaches in the isolation and identification of the unknown bacteria. In an observation made in the laboratory, about 40% of fruit flies ( D. melanogaster ) used in a class experiment died due to infections caused by unknown microbes. The dead flies were examined, and pathogenic microbes in them were isolated for identification. The following are two aims of the experiment performed in the laboratory to isolate and isolate the unknown bacteria:   * To isolate unknown pathogenic microbe that infected fruit flies and caused their death.   * To identify unknown pathogenic