Presentation on theme: "Control of Microbial Growth Tim Ho University of Alberta, Canada * The materials are mostly based on Dr. Brian Lanoil’s Microb 265 1 Part."— Presentation transcript:
Control of Microbial Growth Tim Ho University of Alberta, Canada * The materials are mostly based on Dr. Brian Lanoil’s Microb 265 email@example.com 1 Part III
Objectives 1.Know 3 methods of microbial control 2.Know the strategies on how drugs control the growth of microorganisms. 3.Understand how do bacteria become resistant to antibiotics. firstname.lastname@example.org 2 Physical agents Mechanical removal methods Chemical agents
email@example.com 3 Antibiotic resistance It is always the serious problem Plasmid transfer, the horizontal gene transfer, is the main cause of resistance Nosocomial infection: an infection occurs in a hospital environment Image: Reacher M H et al. BMJ 2000;320:213-216
firstname.lastname@example.org 4 Image: http://textbookofbacteriology.net/resantimicrobial_3.htmlhttp://textbookofbacteriology.net/resantimicrobial_3.html Bacterial mechanisms of Antibiotic resistance Exclusion: active efflux from the cell Enzymatic inactivation: enzyme is produced to inactivate antibiotic molecule Modification of antibiotic or target
email@example.com 5 3 Sources of resistance genes Bacterial chromosomes: - Spontaneous mutations cause drug target sites change Plasmids: - R plasmids: resistance - can be transferred to other cells by horizontal gene transfer - Can carry multiple genes Mobile genetic elements: -Transposons, integrons - can be freely exchanged between bacteria
firstname.lastname@example.org 6 Horizontal gene transfer in bacterial cell 1.Transformation: transfer of free DNA from environment 2.Conjugation: require contact 3.Transduction: transfer gene by viral delivery Image: http://textbookofbacteriology.net/resantimicrobial_3.htmlhttp://textbookofbacteriology.net/resantimicrobial_3.html
email@example.com 7 How to prevent drug resistance Drug should be given in high concentration Give two or more drugs at the same time Use drugs ONLY when necessary Future solutions: develop new drugs, use bacteriophages to treat bacterial disease… WHY: make sure the drug kill all bacteria otherwise it is high possibility that few resistant bacteria remain in body and starts to grow.
Your consent to our cookies if you continue to use this website.