By Heide Ames, Janet Meszaros
In 1929, Dr. Fleming discovered penicillin when a mold contaminated his petri dishes that were growing Staphylococcus, but it took approximately 10 years for the first human trials could begin. Thanks to collaborative efforts by British and American scientists, mass production was accomplished towards the end of World War I with wide prescription use by 1946.1 The first strains of penicillin resistant bacteria were discovered before this; E. coli in 1940 and four strains of S. aureus in 1942.
Antibiotics are found throughout the microbial world. Microorganisms produce toxins like penicillin to protect themselves and their food sources. However, through mutation or gene transfer, organisms once susceptible to the toxins develop ways to alter the danger from toxins.
Learning Objectives
- Explain how multidrug-resistant organisms (MDRO) came to exist
- Identify SPD tactics to protect staff and patients from MDRO
About the Author

Heide Ames, BS, CCSVP is a senior product manager with over 30 years of healthcare and laboratory experience in various roles including as a researcher, author, instructor, tutor and presenter for numerous topics including: biology, microbiology, sterilization validations, medical device processing, sterility assurance uses and applications, and process failure investigations.

Janet Meszaros, BS, MS is a lead scientist and college instructor with over 30 years of laboratory and education experience. At STERIS she has served as a researcher, author, and presenter, and at the college-level she has provided instruction in the areas of chemistry, biology, biological chemistry, microbiology, and anatomy and physiology.
