Bacteriology I and IIMargie A. Morgan, PhD D(ABMM)

Cedar-Sinai Medical CenterLos Angeles, CA

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