Chapter 6, Problem 1CCS

Culturing Microorganisms

One of Koch’s postulates for demonstrating that a certain agent causes a specific disease requires that microorganisms be isolated and cultivated (Chapter 1). Medical laboratory personnel must also grow pathogens as a step in the diagnosis of many diseases. To cultivate or culture microorganisms, a sample called an inoculum (plural: inocula) is introduced into a collection of

Clinical Case Study Cavities Gone Wild

Five-year-old Daniel appears to be shy. He always looks at the floor, has no friends, never plays with the other children, and will rarely speak to adults. When he does speak, it is difficult to understand his broken enunciation. His skinny frame and the dark circles under his eyes make him appear malnourished. Daniel cries frequently and misses many days of school.

A speech specialist at school finds that only two of Daniel’s teeth are healthy; all the others have rotted away to the gum line. The little guy is in constant pain, and it hurts to chew. A doctor later determines that bacteria from the cavities in his mouth have entered his bloodstream and infected his heart, causing an irregular heartbeat and poor blood circulation.

1. 1. How does knowledge of biofilms help explain the bulk of Daniel’s problems?
2. 2. What can Daniel, his parents, and health care professionals do to cure his diseases?
3. 3. What is the scientific name of the nutrient that Daniel’s parents should eliminate from his diet to help prevent a repeat of this condition?
4. 4. A recent study has shown that brushing does more than clean plaque from the teeth; it also disrupts associations between oral bacteria. How does this simple act help prevent the formation of biofilms?