Fastidious microorganisms can grow only in nutrient rich media that support their growth, such as blood agar media. Sheep and horse blood are most commonly used blood for the isolation of such fastidious microorganisms. However, in many countries, sheep is not a common livestock. Hence, different blood agar plates prepared from the citrated human blood and blood of cow, buffalo, pig, and goat (which are common livestock in Nepal) were evaluated for the growth, colony morphology, colony size and hemolysis of the hospital isolates, Escherichia coli, Klebsiella pneumoniae, Pseudomonasaeruginosa, Shigella, Salmonella typhii, Staphylococcus aureus, Streptococcus pyogenes and an unknown hospital isolate. All observations were done in 24 hours and 48 hours. Good growth was seen on almost all blood agar plates and there was no significant variation in the colony morphology of the isolates. Hemolysis was also similar in all blood agar plates. But cow and pig blood gave better results in terms of hemolysis and colony morphology. In general, we can conclude that cow and pig blood can be used as suitable alternatives for sheep blood in blood supplemented agar media. Despite the good qualities of cow and pig blood agar observed in this study, however, there is a need for it to be tested further for its ability to support more fastidious organisms.
