bacterial colonies culture on selective agar media xlt agar (xy

agar air all aureus background bacteria bacterial bacterium biology biotechnology black blood cabondioxcine cell colonies colony color contains culture danger dish focus grains growth health healthcare hygiene isolated lab laboratory light lysine media medical medicine medium micro microbe microbiology oxidase pathogen pathogens petri plate plates red research risk safety science scientific selective small streak surface tergitol test treat xlt xy xylose yellow