WILTIMS #197: Mmm mmm, parasites!

We started a new section on microbiology today with lectures on parasitology. The two main types of medically relevant parasites are so different from each other that it's amazing they are associated. Whereas the various bacteria I've talked about in the past few weeks are all fairly closely related, protozoa and helminths are in different kingdoms. In a well played joke, our professor pointed out that helminths are more closely related to parasitic members of congress (or any of the rest of us) than to protozoa.

TIL: Mycobacteria are tiny - so tiny in fact that they were once thought to be viruses. One of the benefits of their diminutiveness is that, unlike typical bacteria, they don't have a cell wall and are thusly resistant to antibiotics that target cell wall formation such as penicillins, cyclosporins and vancomycin.

Tetracycline antibiotics are not recommended for pregnant women and children younger than 9 years old because they will stain a child's still-implanted permanent teeth gray.

Superinfection is super-awful. That's the term for when you already have one infection and, before you've had a chance to recover, you get a second one. We see this with things like C. difficile where the patient is being treated for one infection and the prescribed antibiotics allow for C. diff. to rear its "difficult" head.

Another example of superinfection we learned of today is when the parasite, Strongyloides stercoralis or threadworm, causes repeated infection in its host through autoinfection. Normally, roundworms transmit to new hosts by releasing eggs through the feces of their current hosts. But threadworms jump the gun and develop to the infectious larval stage before they are excreted... meaning that they can chew into the colon and/or anal region of the host that is already infected.

Sorry about that last tidbit... and just be glad I didn't share any pictures.