Culture Techniques for Bacteriology Lesson 7-3 Culture Techniques for Bacteriology

Culture Techniques Master basic techniques Aseptic technique Safe work practices Correct selection and use of growth media

Aseptic Technique Set of safe work practices to Prevent infection from specimens Prevent infection from cultures Prevent cross-contamination of cultures Prevent environmental contamination of cultures Prevent work surface contamination

Aseptic Technique Physical barriers Protective clothing Safe use of equipment Sterilizing loops Avoiding creation of aerosols Class II safety cabinets HEPA filter

Aseptic Technique

Aseptic Technique Disinfection Sterilization Disinfectants – surfaces Antiseptics – skin Factors affecting efficacy See Tables 7-14 and 7-15 Sterilization

Growth Media Can be liquid or solid (agar) Purposes Recover organism from specimen Support growth of organism Isolation of organism See Tables 7-16, 7-17

Primary Medium Medium inoculated first Choice affects culture success Blood agar is common choice Enriched medium can be required Chocolate agar

Selective Medium Inhibits some organisms and allows others to grow Eosin Methylene Blue (EMB) MacConkey’s agar (MAC)

Indicator Medium Shows metabolic/chemical reaction Some media are both selective and indicator EMB and MAC Hektoen enteric (HE)

Culture Techniques Safety Precautions Standard Precautions PPE Aseptic technique Hand hygiene Surface disinfection Autoclave materials before disposal

Culture Techniques Quality assessment Internal program Media and reagent checks Control organisms Equipment monitoring External program Proficiency testing

Culture Techniques Specimen collection Transport media Technique important Correct supplies Transport media Follow procedure manual Select appropriate medium

Culture Techniques Inoculating the agar plate Bacterial smear Streak for isolated colonies Bacterial smear

Culture Techniques Streaking the agar plate

Culture Techniques Inoculating the agar slant Indicator/selective medium

Culture Techniques Incubate inoculated media 35° to 37° C Agar plates upside down Oxygen/carbon dioxide requirements Aerobic cultures Anaerobic cultures Cultures requiring increased CO2

Culture Techniques Observe culture after 24 hours Isolated colonies Colony characteristics Presence (or absence) of hemolysis This project was funded at $3,000,000 (100% of its total cost) from a grant awarded under the Trade Adjustment Assistance Community College and Career Training Grants, as implemented by the U.S. Department of Labor’s Employment and Training Administration. Rogue Community College is an equal opportunity employer/program. Auxiliary aids and services, alternate form and language services are available to individuals with disabilities and limited English proficiency free of cost upon request.   This work is licensed under a Creative Commons Attribution 4.0 International License.