Do you think those medical instruments are clean?

Kira Stitt (11 AM Micro) found an article about the importance of aseptic technique (here and here).

Listeria monocytogenes

Recently, Listeria monocytogenes has been in the news because of the outbreak in cantaloupes. L. monocytogenes is a non-endospore producing, gram positive bacteria that live in soil and food (Bauman, 2011) The Lysteria bacteria is able to avoid the immune system by avoiding phagocytosis, replicates inside the phagocyte, and uses the phagocyte cellular components to make a tail to swim through the phagocyte. When the phagocyte extends a pseudopod, it pushes through and enters another phagocyte and starts the process again. This bacteria enters the body through contaminated food and drink. For the following case though, L. monocytogenes did not enter the body through food or drink, but through a medical instrument, and is the first case of its kind in a pediatric patient.

A three-year-old boy was admitted to the hospital with headaches, a fever, and abdominal pains. The boy was also premature and had hydrocephalus (also known as water in the brain), and was being treated with a ventriculoperitoneal shunt. A ventriculoperitoneal (VP) shunt and two catheters are placed in the brain and the stomach to treat hydrocephalus. As fluid builds in the brain, it drains down from the brain into the stomach relieving the pressure (Sheth, 2011).

The problems had started 5 days before admittance to the hospital. Not only was the incision red where the VP shunt was inserted, there was no fluid collected from the shunt. The child was given medicine for the abdominal pain and there didn’t appear to be any puncturing to the stomach or other organs. The child was sent home with antibiotics, but then re-admitted 15 days later while exhibiting the same problems.

Blood tests were conducted and it was found that there was an increased count of white blood cells and antibiotics were given to the child. One of the catheters was removed and tests were ran on it, while a new catheter was placed. The child worsened as the fever rose to 40˚C. Cultures were taken from the fluid drained, and the presence of L. monocytogenes was detected. Two days after this fluid was collected, more fluid was collected and had 100 times more L. monocytogenes than the original sample, but the bacteria could not be retrieved from fecal matter.The medical devices were then removed after the diagnosis, and the child improved significantly.

Infections are very common in VP shunts and can to lead to meningitis. The usual bacteria found in shunt infections are Staphylococcus epidermidis and S. aureus. Having L. monocytogenes in a shunt infection is rare and very life threatening. This case shows that Lysteria can form biofilms on medical instruments and persist inside the human body once placed there. Lysteria is also a problem in the food industry and it is believed that this case shows that medical devises should be immediately removed to  reduce the infection. Additionally, this case shows that even though medical devises are treated with antibiotics before placed in patients, they can still have biofilms of dangerous bacteria. The lesson learned from this case is that medical equipment may be sterilized, but there can still be deadly biofilms and bacteria waiting there to infect their unfortunate victim.

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About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on December 10, 2011, in Guest Post. Bookmark the permalink. Comments Off on Do you think those medical instruments are clean?.

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