Journal de médecine vétérinaire et de santé

Abstrait

Laboratory Practical Work on Colony Count, Motility Test and Antimicrobial Susceptibility Test

Alemayehu Choramo Diko

In this practical laboratory works, three points were focused. These are: Anti-microbial susceptibility test, colony counting, and motility test. Each points discussed in detail as follows. Anti-microbial susceptibility test performed by using disc diffusion method to determine susceptibility of salmonella .In this test, kanamycin formed 24.26 mm ,ciprofloxacin formed 34.23 mm, and chloramphenicol formed 28.46 mmzone of inhibition, while sulphonamides formed no zone of inhibition. Colony counting was done by plate count method. Two medias were used. On VRB (violet red blue agar) media, with dilution of 10-2 was CFU/ml=3.5*103, with dilution of 10-3, CFU/ml=4.1*104 and with dilution of 10-4, CFU=1.5*105. But in this case also it is reported as “TFTC= too few to count”. While on PCA (plate count agar) media, with dilution of 10-3 colony counted was 100, and CFU/ml=1.00*105,with dilution of 10-4 colony counted was 171, and CFU/ml=1.71*106 , with dilution of 10-5colony counted was 58, and CFU/ml=5.8*106,with dilution of 10-6colony counted was 19, and CFU/ml=1.9*107,but in this case it is reported as “TFTC= to few to count”. On the other hand, motility test was done in SIM (sulphure- indole -motility) and results obtained were: Staphylococcus aureus was non-motile; grow only on the line of stab, Escherichia. Coli spp. were motile, grow and move throughout the medium and Salmonella was both motile and produced gas.