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=75

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