For example all breeds of domestic dogs belong to one species Dogs belong to a different species than coyotes but these two species are similar enough to be included in the same genus Wolves dogs and coyotes share enough characteristics to be included in one family Traditionally two organisms were considered to belong to the same species if members of the opposite could mate and produce viable fertile offspring The classification of bacteria is not straightforward because 1 bacteria do not reproduce sexually so they do not mate 2 bacteria may look very much alike when viewed through the microscope but may not be related closely and 3 bacteria can acquire DNA horizontally through conjugation for example from various microbes Phenotypic bacterial classification schemes utilize the Gram stain bacterial morphology staining properties growth requirements and biochemical tests The environmental reservoir of the organism vectors and means of transmission of the pathogen are of importance to clinicians The ability of bacteria to grow in the absence or presence of oxygen is an important characteristic in classifying bacteria for example Bacteroides found in the large intestine are strict anaerobes The types of biochemical reactions each organism can perform serve as a thumbprint for identification For example the catalase test identifies microbes that produce the enzyme catalase such as Streptococcus species Data Wor FGK Figure Catalase G C moles 43 Gelatin hydrolyzed Gram stain A H S produced Indole produced Lactose fermented Metabolism Methyl red Sterols required Voges Proskauer Glucose fermented Acid gas Methyl red Sterols required Voges Proskauer G 53 Figure Catalase G C moles Gelatin hydrolyzed Gram stain H S produced Indole produced Lactose fermented Metabolism 50 Glucose fermented Acid gas H FEH C Acid Acid only only 2 8 1EFE 45 58 Anaerobe Acrobe Anaerobe Facultative Facultative Facultative anaerobe anaerobe anaerobe I 60 Q D Acid only 40 Acid only Facultative anacrobe Acrobe Acrobe Acrobe J 1111 B 66 E 30 Acid only K S JE Facultative anaerobe Acid gas H F 53 ODJ Acid gas OE I