Nutrición,Condiciones de Cultivo y Fases de Crecimiento Temperatura: Psicrófilas: crecen óptimamente en temperaturas bajas < 20 grados C. Mesófilas: crecen óptimamente a temperatura ambiente > 20- 40 grados C Flora normal del cuerpo= comensales Termófilas: Crecen a temperaturas altas
pH Mayoría Bacterias patógenas: crecen en ambientes de Ph 6.5- 7.5. Algunas toleran ambientes ácidos: flora gastrointestinal Otras como Vibrio cholerae crece en pH alcalinos.
Requisitos de oxígeno Aeróbicos Anaeróbicos facultativos Microaerofílicos capneicosrequieren más CO2 que O2 Anaeróbicos estrictos: oxígeno es letal
Gas Pak System GasPak Plus® Hydrogen + CO2 with Safety- Shielded Integral Palladium Catalyst Strip For CO2-enriched anaerobic environment.
Enlace http://www.microbiologytext.com/index.php ?module=Book&func=displayarticle&art_id=7 5
http://www. monografias http://www.monografias.com/trabajos27/crecimiento-bacteriano/crecimiento-bacteriano.shtml#ciclo
http://www.javierhuertas.com/PTMA-04-05.html
Phases of Growth 4 Phases 1. Lag Phase 2. Log Phase 3. Stationary Phase 4. Death Phase
1. Lag Phase Bacteria are first introduced into an environment or media Bacteria are “checking out” their surroundings cells are very active metabolically # of cells changes very little 1 hour to several days
2. Log Phase Rapid cell growth (exponential growth) population doubles every generation microbes are sensitive to adverse conditions antibiotics anti-microbial agents
3. Stationary Phase Death rate = rate of reproduction cells begin to encounter environmental stress lack of nutrients lack of water not enough space metabolic wastes oxygen pH Endospores would form now
3. Stationary Phase Death rate = rate of reproduction cells begin to encounter environmental stress lack of nutrients lack of water not enough space metabolic wastes oxygen pH Endospores would form now
4. Death Phase Death rate > rate of reproduction Due to limiting factors in the environment