purple fish guts

Monday, February 21, 2005

Adventures in Microbiology

Science Fiction Twin feels his job in textbook publishing is too boring to blog about. Others like Streetdoc the paramedic blog exclusively about their jobs. A precious few like Kevin at Short Attention Span seem to have a job somewhat similar to mine, although I haven't found anyone with a job similar to mine who blogs about it. I have hesitated to blog about my job until now. Most people don't want to hear exciting exploits about E.coli or tapeworms. In fact, if you cringed at the word tapeworm, please stop reading now. My dear husband sweetly listens to my stories of work, but will beg me to share after the meal if the topic is unsettling. I forget that the topics we routinely talk about over lunch at work are not polite dinner conversation for the average person. "One of the patients at work had two different species of roundworm ova in his stool today! Please pass the spaghetti..."

I work in the microbiology department in a hospital. Some days I look at all of the urine cultures to determine what if any bacteria is growing in a patient's urine and what antibiotics the bacteria are susceptible to. Other days I might evaluate stool cultures, respiratory cultures, blood cultures, etc. Often the highlights come in parasitology. Des Moines has a sizable refugee population, and each refugee has a physical including an ova and parasite exam soon after he or she arrives. Many come harboring that which makes my job interesting.

The highlight this month was a tapeworm. We normally receive a stool specimen preserved in formalin. We examine the stool through a microscope looking for single-celled parasites like Giardia, or the ova (eggs) of the bigger parasites. In this case, though, the patient submitted about a dozen proglottids (segments of a tapeworm) for us to evaluate. After concentrating and examining the formalin the proglottids were submitted in, I found ova that were definately Taenia species. We typically don't differentiate between Taenia solium (pork tapeworm) and Taenia saginata (beef tapeworm). The eggs and proglottids look the same in both, and we rarely receive the proglottids. I've never been happy with just reporting Taenia species, because the pork tapeworm can cause a nasty complication called cysticercosis that the beef tapeworm doesn't. However, I had read somewhere that the species can be differentiated by injecting India ink into the uterine pore (hole in the side of the proglottid where eggs are laid) and counting the uterine branches. It took a couple of messy attempts, but I was ultimately sucessful determining the tapeworm to be Taenia saginata, the beef tapeworm. The patient and physician can rest assured that the patient is not harboring any nasty cysticerci.

My best days are the days when I can go the extra mile to help out a patient. And that is what makes an exciting day in microbiology...