Transcript Practical 6 - Physiology of bacteria

Practical 6 - Physiology of bacteria
• Knowledge of physiology enable to prepare required
conditions for laboratory detection:
• oxygen - O2, CO2, without O2, defined
athmosphere - (Campylobacter, Helicobacter)
• temperature - usually 37*C, 42*C - Campylobacter,
22*C - Pasteurella, different look according to the
temperature - motility, fungi - molds/yeast
• blood - annimal blood - sheep, horse - blood agar,
denaturated blood - chocolatised agar
• nutrition factors - vitamins, aminoacid,
detoxification materials……………...
Cultivation
• Multiplication of bacteria and fungi in laboratory conditions
- artificial media
• Usually lost some properties of metabolic
activities, virulence, change genetic information incorporation
• Biological material - striked on the plate or innoculated to
the cultivation medium (solid or liquid) - for multiplication thick, dense growth
• - for isolation - isolated colonies on solid plate media
Identification of colonies
visual
• Description of growth on liquid medium:
- turbidity, density
- sediment
- surface membrane
• Description of growth on solid media
- shape, look ( dry, mucous), color- pigment, smell,
colony edges, spread of colonies, localisation of
colonies, change of environment, consistence,
Hemolysis
• Change of blood
- alfa hemolysis - green - viridation
- beta hemolysis - transparent - real hemolysis
- gama hemolysis - no change
Cultivation media
• Basical (multiplication, transport)
- solid: blood agar, Muller Hinton agar,
- liquid: bouillon, Muller Hinton bouillon,
• Diagnostic - visualise certain kind of bacteria the color of colonies of different kind of bacteria
is different
• Selective - contain substances that enable growth
of one kind of bacteria and inhibits other
bacteria * ATB (broad spectrum) - eliminate
susceptible bacteria , concentration of NaCl,…..
• Special - defined - detection of some properties
• Combination
Innoculation
• On solid plate medium - multiplication, isolated
colonies
• On solide tube medium - striking, innoculation by
one puncture
• On liquide tube medium
Demostration
• Hemolysis - alfa - Streptococcus pneumoniae
- beta - Streptococcus agalactiae,
- gama - Staphylococcus epidermidis
• Pigment . Staphylococcus aureus - yellow,
Staphylococcus epidermidis - white
• Look - dry - Staphylococcus epidermidis
- mucous - Klebsiella pneumoniae
Colony
• Colony arises from a CFU - colony forming unit a piece of biological material from which a certain
quantity grow on the same place: 1 colony =
thousands of bacteria (microscopy)
• Diagnostic - visualise certain kind of bacteria - the
color of colonies of different kind of bacteria is
different - (biochemical properties) - DC agar,
Endo, Hajn agar, urea agar, esculin agar, SC agar
• Selective - contain substances that enable growth of
one kind of bacteria and inhibits other bacteria
ATB (broad spectrum) - eliminate susceptible
bacteria , concentration of NaCl,…..
- manit salt (combination)
- chocolatised agar
- McConckey
- Karmali
- for M. tbc - Lowenstein, Ogawa,
Colonies - morphology
• in /mms/
• Shape
dot,circular,irregular,spindler,filamentous,amoeboid
• augmentation
plate, convex, umbilical, convex in the center …….
• Edges
smooth, lobar, coroded, filamentous, undulant,
• Color
• Surface - dry, mucous, granular, smooth
• Density - transprent, dense, translucid
• Consistence - buttery, viscous, membranous, smooth