1. Bacteriology I and II
Margie A. Morgan, PhD D(ABMM)
Cedar-Sinai Medical Center
Los Angeles, CA

2. Beginning definitions
• Obligate Aerobe – require oxygen (20%) to grow
• Obligate Anaerobe –>30 min of oxygen exposure can be toxic
• Facultative anaerobes – grow in aerobic and anaerobic
conditions, most “aerobic” bacteria are actually facultative
• Microaerophilic – Grow better with reduced oxygen and
elevated Carbon dioxide %
• Aerotolerant anaerobes– anaerobe not killed by prolonged
exposure to oxygen – example: Clostridium tertium
• Lag Phase - >24 hrs old, growth slowing, not appropriate for
biochemical or susceptibility testing
• Log Phase – Exponential growth – appropriate for all testing
• Stationary phase – appropriate for transporting specimens