Where are some good places to “swab” for Streptococci, Staphylococci and E. Coli?
Streptococci are common in the mouth; it makes up the largest proportion of any bacteria in dental carries. A typical strep from the mouth is Streptococcus pyogenes. Staphylococcus is common on the skin of any mammal. Most likely you would isolate S. hominis, S. epidermidis, S. hemolyticus, or S capitis. Even though it makes the news alot, S. aureus is not terribly common on the skin of healthy mammals. E. coli is found in sewage and waste water. Try taking sample from a river or stream. A couple tips/hints: ~ Use a wet swab to get samples from skin. Sterile water works well. ~ When streaking for isolates from skin, in general, Staphylococcus will be very small white colonies. You will most likely find Micrococcus, too — a very large, dull, bright yellow colony. ~ If looking for S aureus, plate your samples on MSA. It makes it much easier to identify your isolates. ~ Streak water samples on EMB to easily distinguish E. coli. ~ Watch for Enterococcus in water samples.
