Transforming a cookbook undergraduate microbiology laboratory to inquiry based using a semester-long PBL case study.

Microbial physiology is a basic course taught throughout biomedical science disciplines. Students study the structure, growth, and metabolism of microorganisms and often find it difficult to learn the information, usually because they fail to see the wider applications. The current microbiology laboratory series describes how to transform a "cookbook" undergraduate laboratory to an inquiry-based one by incorporating problem-based learning. The students use a food poisoning case study that develops over a series of seven experiments and take on the role of the microbiology technician who is responsible for coming up with the answer and submitting a report to a clinician. The case provides coherence to the sessions, and the students are given the opportunity to learn about, and practice, common techniques they would encounter in a clinical microbiology laboratory. Those include the aseptic method, cultivation of bacteria, quantification of bacteria in culture, isolation of pure culture, morphological observation by light microscopy, Gram staining, the use of selective and differential media, and the effectiveness of a variety of antimicrobials and antibiotics. This laboratory series has been designed so that it can be implemented in any setting, using simple materials and inexpensive, nonspecialized equipment. The experiments are carried out in small groups, and a facilitator may tutor up to two groups of 10 students at a time. The current method has been successfully implemented for the past 2 yr, and the students demonstrated greater motivation in learning and understanding.