Wednesday, August 18, 2010

Salmonella typhimurium

Just in time for the egg recall! Salmonella typhimurium, this probably isn't the same strain involved in the recall but the gram stain would be similar. Still a nasty bug!

Pseudomonas aeruginosa


Pseudomonas aeruginosa has some brilliant reactions on specific media. We only culture it on TSA, but if we let it grow for more than 24 hours the dense colonies turn a blue-green color. My favorite reaction is on Centrimide agar, where it turns a fantastic florescent yellow-green. It likes to lurk in dirty hot tubs, so beware!

Escherichia coli

Escherichia coli, I think this was just a generic strain from ATCC and not 0157:H7 or any other emerging strain. E. coli is abundant in the intestinal tracts of mammals and is considered a fecal contaminate, some strains like 0157:H7 are enterohemorrhagic, which in a nutshell means they burrow into your intestines causing inflammation, diarrhea and bleeding. You'd be surprised how many people don't understand my "E. coli happens" shirt.

Candida albicans

One of my absolute favorites for morphology and color! Candida albicans is a yeast commonly found in the vagina, mouth and on skin, but it is an opportunistic pathogen and can cause yeast infections and thrush when there is a change in the body's normal flora (antibiotics, for example).

Bacillus spp.


This one threw me for a loop, I thought I had found some filamentous bacteria like Actinomycetes, but I did a little more research (books in the lab and online research) and talked to my manager who informed me that when a Bacillus culture is contaminated they can bunch together and form chains like these.

Bacillus spores


This Bacillus spp. culture had me SO EXCITED because its difficult to find such clearly defined spores when you're not performing a spore specific stain. See them?

I was running around the lab showing everyone because I've looked at dozens of Bacillus cultures this week and had the hardest time finding at least one spore, this was like Christmas!