Transcript penicillium cephalosporium

MICROBIAL
NUTRITION,
GROWTH,
MEASUREMENT,
AND CONTROL
RESOURCES ON LINE
• http://www.bact.wisc.edu/Microtextbook/i
ndex
• AN ONLINE TEXTBOOK
• http://www.bact.wisc.edu/bact100/Kimball
Links.html
• http://science.nhmccd.edu/Biol/microbio.ht
ml
• http://science.nhmccd.edu/BioL/animatio.h
tm
MICROBIAL
NUTRITION
MICROBIAL HABITATS
• OCEANS
• ANTARCTIC ICE CAP
• VERTEBRATE AND INVERTEBRATE
GUT
• JAMS, JELLIES, PICKLES
• VIRTUALLY EVERYWHERE
MICROBIAL NUTRITION
• ORGANISMS MUST GET FOOD FROM
ENVIRONMENT
• WIDE VARIETY OF NUTRITIONAL
STRATEGIES
• http://www.mansfield.ohiostate.edu/~sabedon/campbl27.htm#photohet
erotroph
NUTRITIONAL TYPES
•
•
•
•
•
PHOTOAUTOTROPHS
CHEMOAUTOTROPHS
PHOTOHETEROTROPHS
CHEMOHETEROTROPHS
http://72.14.203.104/search?q=cache:EkMmMJD4
ZtIJ:rcw.raiuniversity.edu/biotechnology/BTechbi
otech/microbesandus/lecture-notes/lecture10.pdf+microbial+nutrition+chemoheterotroph+ph
otoheterotroph+photoautotroph&hl=en&gl=us&ct
=clnk&cd=5
• http://www.sinauer.com/perry/Perry_SG_05.pdf
PHOTOAUTOTROPHS
• LIGHT AS ENERGY SOURCE
• CARBON DIOXIDE AS CARBON
SOURCE
• H2O, H2, OR H2S AS ELECTRON
DONOR
• http://72.14.203.104/search?q=cache:sclpkx
yy_VMJ:www.homepage.montana.edu/~um
bls/mb301/lecquiz2key.pdf+photoautotroph
&hl=en&gl=us&ct=clnk&cd=26
OXYGENIC
PHOTOSYNTHESIZERS
•
•
•
•
OXYGEN GIVEN OFF
GENERATED FROM WATER
PHOTOSYSTEM II PRESENT
CYANOBACTERIA, ALGAE, AND
GREEN PLANTS
• http://72.14.203.104/search?q=cache:3iUlq0
IL7tsJ:meetings.copernicus.org/egu2005/do
wnload/EGU05-J-111981.pdf+oxygenic+photosynthesizer&hl=en&
gl=us&ct=clnk&cd=5
ANOXYGENIC
PHOTOSYNTHESIZERS
•
•
•
•
DO NOT USE WATER
USE H2S, H2 , SULFUR OR SULFIDE
USE BACTERIOCHLOROPHYLLS
http://72.14.203.104/search?q=cache:3iUlq0
IL7tsJ:meetings.copernicus.org/egu2005/do
wnload/EGU05-J-111981.pdf+anoxygenic+photosynthesizer&hl=en
&gl=us&ct=clnk&cd=2
PHOTOHETEROTROPHS
• LIGHT AS ENERGY SOURCE
• NEED ORGANIC COMPOUNDS OR
HYDROGEN GAS AS ELECTRON
DONOR
• GREEN NONSULFUR BACTERIA
• PURPLE NONSULFUR BACTERIA
• http://www.sinauer.com/perry/MicrobialLife
05.pdf
CHEMOAUTOTROPHS
• REDUCED INORGANIC MOLECULES ACT AS
CARBON AND ENERGY SOURCES
• INORGANIC MOLECULE FINAL ELECTRON
ACCEPTOR
• CARBON DIOXIDE ACTS AS CARBON SOURCE
• ENERGY OBTAINED FROM H2, NH3, H2S,
ELEMENTAL SULFUR, NO2 and Fe+2.
• http://uweb.cas.usf.edu/~kscott/chemoautotrophy.htmhttp://
highered.mcgrawhill.com/sites/0078664276/student_view0/unit1/chapter4/ch
eck_challenge_quiz_3.html
CHEMOHETEROTROPHS
• USE PREFORMED CARBON
COMPOUNDS AS ENERGY AND
CARBON SOURCE
• USUALLY THE SAME ORGANIC
COMPOUND
• FUNGI, ANIMALS, PROTOZOA AND
MOST BACTERIA
• http://www.bact.wisc.edu/bact100/origins.ht
ml
SAPROPHYTE VS PARASITE
• SAPROPHYTE USES DEAD ORGANIC
MATTER
• PARASITE USES LIVING HOST
MICROBIAL NUTRITION
• http://www.mansfield.ohiostate.edu/~sabedon//biol2015.htm
• http://www.agen.ufl.edu/~chyn/age4660/lec
t/lect_02/lect_02.htm
MACRONUTRIENTS
•
•
•
•
•
•
•
•
NEEDED IN LARGE AMOUNTS
CARBON
HYDROGEN
OXYGEN
NITROGEN
PHOSPHORUS
SULFUR
http://www.biologie.uni-hamburg.de/bonline/library/micro229/terry/229sp00/lectures/nut
rition.html
CARBON
• FORMS CARBON SKELETON OF
ORGANIC MOLECULES
• CARBON DIOXIDE MOST COMMON
SOURCE
OXYGEN
• FOUND IN MOST ORGANIC
MOLECULES
• ATMOSPHERIC
• CHEMICALLY BOUND
• OXYGENASES
TOXIC OXYGEN
COMPOUNDS
•
•
•
•
•
OXYGEN ITSELF
HYDROGEN PEROXIDE
SUPEROXIDE RADICAL
HYDROXYL RADICAL
http://www.sigmaaldrich.com/Area_of_Inter
est/Biochemicals/Enzyme_Explorer/Cell_Si
gnaling_Enzymes/Superoxide_Dismutase.ht
ml
ENZYMES THAT DETOXIFY
FREE RADICALS
• SUPEROXIDE
DISMUTASE
• CATALASE
• PEROXIDASE
OXYGEN RELATIONSHIPS
• OBLIGATE AEROBES
• FACULATIVE ANAEROBES OR
FACULATIVE AEROBES
• MICROAEROPHILES
• AEROTOLERANT ANAEROBES
• OBLIGATE ANAEROBES
• http://www.jlindquist.net/generalmicro/dfthi
ognf.html
HYDROGEN
• FOUND IN ORGANIC MOLECULES
• CHEMIOSOMOSIS
• REDUCES CARBON DIOXIDE IN
CALVIN CYCLE
PHOSPHORUS
• FOUND IN ATP
• PHOSPHOLIPIDS
NITROGEN
• COMPONENT OF NUCLEIC ACIDS
• COMPONENT OF PROTEINS
• COMPONENT OF COENZYMES
SULFUR
• COMPONENT OF ACETYL COA
• COMPONENT OF PROTEINS
• MOST MICROBES USE SULFATE
OTHER ELEMENTS USED BY
MICROBES
•
•
•
•
POTASSIUM
MAGNESIUM
IRON
CALCIUM
IRON
• COMPONENT OF HEME GROUPS
• FERRIC AND FERROUS FORMS
• CHELATORS INCREASE ABSORPTION
MICROELEMENTS
•
•
•
•
•
MOLYBEDNUM
COBALT
COPPER
NICKEL
MANGANESE
OTHER ELEMENTS USED BYA
RELATIVE FEW ORGANISMS
• SELENIUM & TUNGSTEN
– ARCHAEBACTERIA
• SODIUM AND CHLORIDE IONS
– HALOPHILES
ACCESSORY GROWTH
FACTORS
•
•
•
•
VITAMINS
FATTY ACIDS
AMINO ACIDS
PURINES AND PYRMIDINES
VITAMINS
• DIFFERENT ORGANISMS HAVE
DIFFERENT VITAMIN NEEDS
• NEEDS CAN VARY WITH CONDITIONS
FATTY ACIDS
• SOME BACTERIA AND PROTOZOA
NEED FATTY ACIDS
• MYCOPLASMAS NEED
CHOLESTEROL OR OTHER STEROLS
AMINO ACIDS
• NEEDS VARY
• MUST INCORPORATE INTO MEDIA
PURINES AND PYRIMIDINES
• SOME MICROBES ARE UNABLE TO
SYNTHESIZE THEIR OWN
• MUST BE INCLUDED IN MEDIA
ADENINE
THYMINE
EUTROPHIC VS
OLIGOTROPHIC
ENVIRONMENTS
EUTROPHIC
ENVIRONMENTS
• ABUNDANCE OF
NUTRIENTS
• NO LIMITING
FACTORS
• CULTURAL
EUTROPHICATION
• http://www.umanitoba.ca/i
nstitutes/fisheries/eutro.ht
ml
SOURCES OF CULTURAL
EUTROPHICATION
• MAN’S ACTIVITY
INCREASES
NUTRIENTS IN
ENVIRONMENT
– FARMING
– SEWAGE
• INCREASE
BIOLOGICAL
OXYGEN DEMAND
– BOD
OLIGOTROPHIC
ENVIRONMENTS
•
•
•
•
FEW NUTRIENTS
STREAMS
RIVERS
SOME SOILS
LABORATORY CULTURE
http://www.bact.wisc.edu/Microtextb
ook/index.php?module=Book&fun
c=displayarticle&art_id=26
NUTRIENT UPTAKE
• SPECIFIC
• OFTEN MUST MOVE AGAINST
CONCENTRATION GRADIENT
• http://users.rcn.com/jkimball.ma.ultranet/Bi
ologyPages/D/Diffusion.html#Facilitated_di
ffusion
• http://web.mit.edu/esgbio/www/cb/membra
nes/transport.html
TRANSPORTATION
MECHANISMS
• DIFFUSION
• OSMOSIS
• FACILITATED
DIFFUSION
• ACTIVE
TRANSPORT
• GROUP
TRANSLOCATION
DIFFUSION
• SMALL NONPOLAR
SUBSTANCES
• DOWN
CONCENTRATION
GRADIENT
• CARBON DIOXIDE
• OXYGEN
• CARBON DIOXIDE
• MOLECULES SPREAD
FROM AREAS OF HIGH
CONCENTRATIION, TO
AREAS OF LOW
CONCENTRATION
• . MOLECULES
EVENTUALLY
EVENOUT
THROUGHOUT A SPACE
- EQUILIBRIUM
• CONCENTRATION
GRADIENT - A
DIFFERENCE BETWEEN
CONCENTRATIONS IN A
SPACE
FACILITATED DIFFUSION
• PASSIVE PROCESS
• PERMEASES
• DOES NOT HAPPEN MUCH IN
PROKARYOTES
• MORE IMPORTANT IN EUKARYOTES
• http://bio.winona.msus
.edu/berg/ANIMTNS/
FacDiff.htm
ACTIVE TRANSPORT
• MOVE MATERIALS AGAINST
CONCENTRATION GRADIENT
• USES ENERGY TO POWER
• CARRIER MOLECULES
• ANTIPORT
• SYMPORT OR COTRANSPORT
SYMPORT OR COTRANSPORT
• http://bio.winona.msus
.edu/berg/ANIMTNS/s
ymport.htm
ANTIPORT
• http://bio.winona.msus
.edu/berg/ANIMTNS/
ANTIport.htm
• http://www.brookscole.com/chemistry_d/te
mplates/student_resources/shared_resources
/animations/ion_pump/ionpump.html
THE PRICE OF ACTIVE
TRANSPORT
• ATP OR OTHER
PHOSPHATE
MOLECULES
• PROTON MOTIVE
FORCE
GROUP TRANSLOCATION
• MOLECULES ARE MODIFIED AS
THEY CROSS CELL MEMBRANE
• PHOSPHOPHENOLPYRUVATE:
SUGAR PHOSPHOTRANSFERASE
• WIDESPREAD IN PROKARYOTES
• VARIETY OF FORMS
http://www.cat.cc.md.us/cour
ses/bio141/lecguide/unit1/
prostruct/group.html
ENDOCYTOSIS VS
EXOCYTOSIS
EUKARYOTIC MECHANISM
ENDOCYTOSIS
• MOVEMENT OF MATERIALS INTO THE CELL
– PHAGOCYTOSIS = ‘CELL EATING’
• BY MACROPHAGES & WBCS
• PARTICLE BINDS TO RECEPTOR PROTEIN
• WHOLE BACTERIA OR VIRUSES ARE ENGULFED & LATER
DIGESTED
– PINOCYTOSIS = CELL DRINKING
• NO RECEPTOR PROTEINS
– RECEPTOR-MEDIATED ENDOCYTOSIS = SELECTIVE
INPUT
• MECHANISM BY WHICH HIV VIRUS ENTERS CELLS
Pinocytosis and Phagocytosis
• No pseudopods form
• Nonselective drinking
of extracellular fluid
• Pseudopods extend
to form phagosome
• Lysosome joins it
PINOCYTOSIS
PHAGOCYTOSIS
Receptor-Mediated Endocytosis
• Mechanism for uptake of specific
substances -- ligands
• Desired substance binds to receptor
protein in clathrin-coated pit region of
cell membrane causing membrane to
fold inward
• Vesicles become uncoated & combine
with endosome
• Receptor proteins separate from ligands
and return to surface
• Ligands are digested by lysosomal
enzymes or transported across cell -epithelial cell crossing accomplished
• http://cellbio.utmb.edu/cellbio/recend.htm#
Menu
EXOCYTOSIS
• MOVEMENT OF
MATERIALS OUT OF
CELL
• ‘CELL VOMITING’
• Vesicles form inside cell,
fuse to cell membrane
• Release their contents
– digestive enzymes,
hormones,
neurotransmitters or
waste products
• replace cell membrane
lost by endocytosis
http://bio.winona.msus.edu/berg/AN
IMTNS/Secrtion.htm
IRON UPTAKE
• USED FOR
CYTOCHROMES
AND ENZYMES
• FERRIC IRON
INSOLUBLE
• SIDEROPHORES
MEDIA USED IN LABORATORY
CULTURE
http://www.life.umd.edu/classroom/b
sci424/BSCI223WebSiteFiles/Chapte
r6.htm
CLASSIFICATION OF MEDIA
• PHYSICAL FORM
• CHEMICAL CHARACTERISTICS
• FUNCTIONAL TYPES
LIQUID MEDIA
• AQUEOUS FORMULATION
• DOES NOT GEL OR SOLIDIFY
AT ROOM TEMP
• FLOW FREELY
• BROTHS
• MILKS
• NUTRIENT SOLUTIONS
SEMISOLID MEDIA
•
•
•
•
SOLID AT ROOM TEMP
GELATINOUS TEXTURE
0.3% TO 0.5% AGAR
USED TO RESTRICT
MOVEMENT OF MOTILE
MICROBES, GROW
MICROAEROPHILES OR
ANAEROBES
• SIM AGAR
• MOTILITY MEDIA
SOLID MEDIA
• PROVIDES FIRM
SURFACE
• LIQUEFIABLE OR
NONLIQUEFIABLE
• DISTINCT
COLONIES FORM
LIQUEFIABLE SOLID MEDIA
• REVERSIBLE
SOLID MEDIA
• THERMOPLASTIC
SOLIDIFYING
AGENT
• AGAR OR GELATIN
GELATIN WAS FIRST
SOLIDIFYING AGENT
• DRAWBACKS
• CAN BE LIQUID AT
ROOM TEMP
• MANY MICROBES
DIGEST
BENEFITS OF AGAR-AGAR
•
•
•
•
COMPLEX POLYSACCHARIDE
SOLID AT ROOM TEMPERATURE
LIQUEFIES AT 100 DEGREES C
DOES NOT RESOLIDIFY UNTIL IT COOLS TO
42 DEGREES C
• CAN BE INOCULATED AND POURED IN
LIQUID FORM
• MOLDABLE AND FLEXIBLE FRAMEWORK
FOR MOISTURE AND NUTRIENTS
• NOT EASILY DIGESTED
NONLIQUEFIABLE SOLID
MEDIA
• NOT
THERMOPLASTIC
• RICE
• POTATOE
• MEAT
• EGG MEDIA
• SERUM MEDIA
• LESS VERSATILE
CHEMICAL CONTENT OF
MEDIA
• CHEMICALLY DEFINED OR
SYNTHETIC
• NONSYNTHETIC OR EMPIRICAL
MEDIA
FUNCTIONAL CATEGORIES
•
•
•
•
GENERAL PURPOSE
ENRICHED
SELECTIVE
ENRICHMENT MEDIA
GENERAL PURPOSE MEDIA
• GROW A BROAD
SPECTRUM
• USUALLY
NONSYNTHETIC
• NUTRIENT BROTH
AND AGAR
• TRYPTIC SOY BROTH
AND AGAR
• BLOOD AGAR
• BRAIN-HEART
INFUSION AGAR
ENRICHED MEDIA
• SIMILAR TO GENERAL PURPOSE
MEDIA
• ENRICHED WITH BLOOD, SERUM,
HEMOGLOBIN, OR GROWTH
FACTORS
• BLOOD AGAR
• THAYER MARTIN AGAR
SELECTIVE METHODS
• SELECTIVE ENRICHMENT
• SELECTIVE REPRESSION
SELECTIVE ENRICHMENT
• VARYING TEMPERATURE
• pH
• CHEMICAL ENVIRONMENT
ENRICHMENT MEDIA
• EXTREMELY SELECTIVE MEDIA
• FAVORS GROWTH OF PATHOGENS
FOUND IN LOW NUMBERS
• SELENITE
• BRILLIANT GREEN
• POTASSIUM TELLURITE
SELECTIVE MEDIA
• HAS AGENT/S THAT INHIBITS
GROWTH OF CERTAIN MICROBES
• SELECTS FOR GROWTH OF OTHERS
• IMPORTANT FOR IDENTIFICATION
FROM SAMPLES
• MANNITOL SALT AGAR
• MacCONKEY AGAR
• EMB AGAR
SELECTIVE REPRESSION
• STOPS OR SLOWS THE THE GROWTH
OF INTERFERING ORGANISMS
• TOXIC CHEMICALS
• TEMPERATURE
DIFFERENTIAL MEDIA
• EXPLOITS PHYSIOLOGICAL & OTHER
CHARACTERISTICS TO DISTINGUISH
COLONIES
• CONTAIN REAGENTS
• DO NOT NECESSARILY ENRICH OR
REPRESS
• BLOOD AGAR
• EMB
DIFFERENTIAL MEDIA
• GROW SEVERAL
TYPES OF
MICROBES
• WILL HAVE
VARYING
APPEARANCES
DUE TO AGENTS
EXAMPLES OF AGARS
EMB AGAR
MacCONKEY AGAR
MANNITOL SALT AGAR
ISOLATING PURE CULTURE
KOCH AND HIS PROCEDURES
KOCH’S POSTULATES
• ORGANISM SHOULD ALWAYS BE PRESENT
IN ANIMALS WITH DISEASE
• NOT PRESENT IN ANIMALS THAT ARE
HEALTHY
• MUST CULTIVATE ORGANISMS IN PURE
CULTURE
• WHEN CULTURE INTRODUCED INTO
HEALTHY ANIMAL SHOULD CAUSE DISEASE
• MUST BE REISOLATED FROM
EXPERIMENTAL ANIMAL
PURE CULTURE TECHNIQUE
• SUCCESS DEPENDS ON HAVING ONLY
ONE MICROBE IN CULTURE
• SOLID MEDIA ALLOWS FOR
DEVELOPMENT OF SINGLE
COLONIES
PETRI PLATES
STREAK PLATE
• DEVELOPED BY
KOCH
• ASEPTIC
TECHNIQUE
POUR PLATE METHOD
• SERIAL DILUTIONS
INTO LIQUID AGAR
PRESERVATION OF
MICROBES
•
•
•
•
SUBCULTURING
REFRIGERATION
DESSICATION
LYOPHILIZATION
ENVIRONMENTAL FACTORS
AND GROWTH
EFFECTS OF TEMPERATURE
CARDINAL TEMPERATURES
• MINIMUM TEMPERATURE
• MAXIMUM TEMPERATURE
• OPTIMAL TEMPERATURE
MAXIMUM TEMPERATURE
• REFLECTS DENATURING OF
PROTEINS AND ENZYMES
MINIMUM TEMPERATURE
• MAYBE DUE TO LOSS OF FLUIDITY IN
CELL MEMBRANE
TEMPERATURE
• EFFECTS ALL
RELATIONSHIPS IN
CELL
• PSYCHROPHILES
• MESOPHILES
• THERMOPHILES
PSYCHROPHILES
• BEST AT 15
DEGREES C OR
LOWER
PSYCHROTROPHS
• ARE ALSO
MESOTROPHS BEST
GROWTH AT 20-30
DEGREES C
– CAN GROW SLOWLY AT
LOW TEMPERATURES
– TOLERATE RATHERE
THAN BENEFIT FROM
THEM
• SPOIL FOOD IN
FRIDGE
– LISTERIA
MONOCYTOGENES
MESOPHILES
• MOST MICROBES ARE MESOPHILES
• HUMAN PATHOGENS ARE
THERMOPHILES
• HEAT LOVERS
• ABOVE 55
DEGREES C
• CAN GROW IN
BOILING WATER
100 DEGREE C
HYPERTHERMOPHILES
• GROW AT 90
DEGREES C OR
HIGHER
• SOME HAVE
MAXIMA ABOVE
100 DEGREES C
• DO NOT GROW
WELL BELOW 55
ENVIRONMENTAL FACTORS
AND GROWTH
ACIDITY AND ALKALINITY
PH AND MICROBIAL
GROWTH
• MOST ORGANIMS
HAVE PH RANGE
• MOST FALL
WITHIN PH 5 - 9
• ACIDOPHILES
• NEUTROPHILES
• ALAKALOPHILES
ACIDOPHILES
• LOW PH OPTIMA
• FUNGI TEND TO BE MORE ACID
TOLERANT THAN BACTERIA
• OBLIGATE ACIDOPHILIC BACTERIA
THIOBACILLUS
SULFOLOBUS
THERMOPLASMA
IMPORTANCE OF
HYDROGEN IONS TO CELL
MEMBRANE STABILITY
• IN NEUTRAL PH CELL MEMBRANE
DISINTEGRATES
• CELL LYSES
ALKALIPHILES
• HIGH PH OPTIMA FOR GROWTH
• SODA LAKES & HIGH CARBONATE
SOILS
• SOME ARE ALSO HALOPHILES
NEUTROPHILES
• MAJORITY OF MICROBES
• PH 6 - 8
HOW TO LIVE IN HIGH AND
LOW PH ENVIRONMENTS
• INSIDE OF CELL MUST BE AT PH
NEAR 7
• MEMBRANE MAY BE IMPERMEABLE
TO H+ IONS
• MAY EXCHANGE IONS ACROSS
MEMBRANE
• CELL WILL MOVE H+ ACROSS
MEMBRANE TO KEEP PH STABLE
MAINTAINING PH IN THE
LAB
• BUFFERS
• WORK OVER NARROW PH RANGE
ENVIRONMENTAL FACTORS
AND GROWTH
WATER AVAILABILTY
OSMOSIS
• HIGH CONCENTRATION TO LOW
CONCENTRATION
• ACROSS CELL MEMBRANE
• http://www.colorado.edu/eeb/web_resource
s/osmosis/
• http://zoology.okstate.edu/zoo_lrc/biol1114/
tutorials/Flash/Osmosis_Animation.htm
POSITIVE WATER BALANCE
• WATER USUALLY DIFFUSES INTO
CELLS
– CAUSING LYSIS OR TURGOR PRESSURE
NEGATIVE WATER BALANCE
• WATER WILL MOVE OUT OF THE
CELL
• CAUSING CRENATION OR
PLASMOLYSIS
OSMOTIC EFFECTS IN HIGH
SALT ENVIRNOMENTS
• SEA WATER --3% NA CL
HALOPHILES
•
•
•
•
MILD HALOPHILES 1-6%
MODERATE HALOPHILES 6-15%
EXTREME HALOPHILES 15-30%
HALOTOLERANT CAN TOLERATE
BUT GROW BEST WITHOUT
EFFECTS OF HIGH SUGAR
ENVIRONMENTS
• OSMOPHILES
EFFECTS OF LOW WATER (DRY)
ENVIRONMENTS
• XEROPHILES
HOW DO MICROBES GROW IN
AREAS WITH LOW WATER
•
•
•
•
COMPATIBLE SOLUTES
PROLINE
BETAINE
GLYCEROL
ENVIRONMENTAL FACTORS
AND GROWTH
OXYGEN
TYPES OF MICROBES
• AEROBES
• MICROAEROPHILES
• FACULATIVE ANAEROBES OR
AEROBES
• AEROTOLERANT ANAEROBES
• OBLIGATE ANAEROBES
TOXIC FORMS OF OXYGEN
•
•
•
•
•
SINGLET OXYGEN 1O2
SUPEROXIDE ANION 1O2HYDROGEN PEROXIDE H2O2
HYDROXYL RADICAL ·OH
ALL ARE BYPRODUCTS OF
RESPIRATION
SINGLET OXYGEN
• NORMAL MOLECULAR
OXYGEN
• AT HIGHER ENERGY STATE
• EXTREMELY REACTIVE
SUPEROXIDE ANION
• O2• HIGHLY REACTIVE
• OXIDIZES ANY ORGANIC MOLECULE
PEROXIDES
• CAN DAMAGE CELL COMPONENTS
• NOT AS TOXIC AS OTHERS
HYDROXYL RADICAL
• OXIDIZES ORGANIC SUBSTANCES
• TRANSIENT
• NOT A LOT MADE UNLESS EXPOSED TO IONIZING
RADIATION
• SMALL AMOUNTS CAN BE MADE FROM
HYDROGEN PEROXIDE
ENZYMES THAT DESTROY
TOXIC OXYGEN PRODUCTS
• CATALASE
• PEROXIDASE
• SUPEROXIDE DISMUTASE
ANAEROBIC MICROBES
• FREQUENTLY LACK MEANS TO
DETOXIFY OXYGEN BY PRODUCTS
ENVIRONMENTAL FACTORS
AND GROWTH
PRESSURE
PRESSURE RELATIONSHIPS
• MOST ORGANISMS
LIVE AT 1
ATMOSPHERE
PRESSURE
• BAROTLERANT
• BAROPHILIC
MICROBIAL
GROWTH
MICROBIAL GROWTH
GROWTH OF POPULATIONS NOT
INDIVIDUALS
DOUBLING TIME
• GENERATION TIME
• DEPENDS ON SPECIES
• DEPENDS ON GROWTH
CHARACTERISTICS
• TELLS HOW FAST POPULATION IS
GROWING
THE WAY WE GROW
• ENLARGE AND DIVIDE WHEN
DOUBLED IN SIZE
• BINARY FISSION
• BUDDING
• BINARY FISSION AND MITOSIS
• MITOSIS AND CYTOKINESIS
EUKARYOTIC CELL DIVISION
•
•
•
•
•
GO PHASE
G1 PHASE
S PHASE
G2 PHASE
M PHASE
C PHASE
GO PHASE
• PRIMARY GROWTH
PHASE OF CELL
• ENLARGEMENT
G1 PHASE
• CELL PREPARES
FOR DNA
REPLICATION
• PRODUCES
ENZYMES
• PRODUCES
NUCLEOTIDES
S PHASE
• SYNTHESIS PHASE
• REPLICATION OF
GENOME OCCURS
G2 PHASE
• PRODUCES
ORGANELLES FOR
M PHASE
• STOCKPILES VITAL
CELLULAR
PRODUCTS
• CHROMOSOME
BEGIN
CONDENSING
M PHASE
• MITOSIS PHASE
• DIVIDES THE NUCLEUS INTO TWO
DAUGHTER NUCLEI
• PROPHASE
• METAPHASE
• ANAPHASE
• TELOPHASE
PROPHASE
METAPHASE
ANAPHASE
TELOPHASE
C PHASE
• CYTOKINESIS PHASE
• DIVISION OF CYTOPLASM AND
ORGANELLES INTO TWO DAUGHTER
CELLS
CYTOKINESIS
BACTERIAL CELL DIVISION
BUDDING
BINARY FISSION
BUDDING
• YEAST LIKE
PROCESS
• But no mitosis occurs
BINARY FISSION
• CHROMOSOMES DO NOT SHUT
DOWN DURING DIVISION
• CELL MEMBRANE REPLACES
MITOTIC SPINDLE
• PRODUCES TWO NEARLY EQUAL
SIZED CELLS
http://www.emc.maricopa.edu/facult
y/farabee/BIOBK/BioBookDiversity
_2.html
PROCESSES INVOLVED
• CELL ELONGATION
• DNA REPLICATION
• CELL DIVISION
CELL ELONGATION
GRAM NEGATIVE BACTERIA
GRAM POSITIVE BACTERIA
DNA REPLICATION
• TIME TABLE CAN
VARY
• MAY HAVE
MULTIPLE
REPLICATION
FORKS
• MAY LEAD TO
MULTIPLE
CHROMOSOMES
CELL DIVISION
• USUALLY BEGINS AS INVAGINATION
• USUALLY AUTOLYSIS TO FORM TWO
CELLS
• GET VARIETY OF ARRANGEMENTS
GRAM NEGATIVE BACTERIA
PLANES OF CELL DIVISION
VIABLE NONCULTURABLE
CELLS
• HAVE ACTIVE METABOLISM
• CAN’T BE GROWN ON CONVENTIAL
MEDIA
• VIBRIO CHOLERAE, LEGIONELLA
PNEUMONIAE
EXPONENTIAL GROWTH
• POPULATION
NUMBERS
INCREASE BY A
FACTOR OF TWO
TYPES OF GROWTH
SYNCHRONOUS VS ASYNCHRONOUS
GROWTH PHASES
• LAG PHASE
• LOG PHASE
• STATIONARY
PHASE
• DEATH PHASE
HOW DO WE KNOW A CELL
IS DEAD
• CANNOT CONTINUE CELLULAR
REPAIR
• CANNOT REINITIATE GROWTH WHEN
INTRODUCED TO NEW MEDIA
LABORATORY CULTURE
METHODS
BATCH VS CONTINUOUS
CULTURE
BATCH CULTURE
• USUALLY TYPE OF BACTERIAL
GROWTH
• SHOWS NORMAL GROWTH CURVE
CONTINUOUS CULTURE
• CHEMOSTAT
COLONY GROWTH
• FORMS FROM SINGLE CELL
• DIFFERENT PHASES OF GROWTH IN
DIFFERENT PARTS OF COLONY
MEASURING MICROBIAL
GROWTH
DIRECT VS INDIRECT
VIABLE VS TOTAL
INDIRECT MEASUREMENTS
• MEASURE PROPERTIES OF
POPULATION
• TURBIDITY
• DRY WEIGHT
• METABOLIC ACTIVITY
DIRECT MEASUREMENTS
•
•
•
•
DIRECT MICROSCOPIC COUNT
ELECTRONIC COUNT
PLATE COUNT
MOST PROBABLE NUMBER
VIABLE COUNT
•
•
•
•
•
COUNTS LIVING CELLS
PLATE COUNTS
MOST PROBABLE NUMBER
METABOLIC ACTIVITY
FILTRATION
TOTAL COUNT
•
•
•
•
TURBIDITY
DRY WEIGHT
DIRECT MICROSCOPIC COUNT
DIRECT ELECTRONIC COUNT
TURBIDITY
• NUMBER IS
PROPORTIONAL TO
WEIGHT OF A SAMPLE
• SPECTROPHOTOMETER
USE OF THE
SPECTROPHOTOMETER
• ESTIMATES MASS
OF DENSE
CULTURES
• CHARTS GROWTH
COMPARED TO
STANDARD
GROWTH CURVE
• ADVANTAGES| • DISADAVANTAGES
RAPIDITY
REPRODUCIBLE
CAN BE USED ONLY ON
DENSE CULTURES
DOES NOT DISTINGUISH
BETWEEN LIVING AND
DEAD CELLS
CAN NOT BE USED ON
CELLS THAT AGGREGATE
NEED STANDARD CURVE
DRY WEIGHT
• CENTRIFUGATION OR
FILTRATION
• DRYING IN OVEN AT
105 DEGREES C FOR 24
HOURS
• ADVANTAGES
USED TO MAKE
STANDARD CURVE
FOR MEASURING
CELL MASS
ACCURATE
REPRODUCIBLE
DISADVANTAGES
TIME CONSUMING
TEDIOUS
SAMPLE MUST
CONTAIN
MORETHAN 10
MILLION CELLS
METABOLIC ACTIVITY
• RATE OF
METABOLITE
PRODUCTION
• UTILIZATION OF
SUBSTRATE
• REDUCTION OF
DYES
ADVANTAGES
CAN BE USED
WITH COMPLEX
MEDIA SUCH AS
MILK OR SOIL
NO INSTRUMENTS
REQUIRED
DISADVANTAGES
INDIRECT
MEASURMENT
DOES NOT GIVE AN
ACCURATE
MEASUREMENT
TIME CONSUMING
DIRECT COUNT
• PETROFF HAUSER COUNTING
CHAMBER
• COULTER COUNTER
PETROFF HAUSSER
COUNTING CHAMBER
COULTER COUNTER
MICROSCOPIC VS ELECTRONIC
COUNTS
• USED IN DIFFERENT SITUATIONS
MICROSCOPIC COUNTS
• ADVANTAGES
– NO EXPENSIVE
EQUIPMENT
– ONLY WAY TO
COUNT IF SAMPLE
CONTAINS
FOREIGN
MATERIALS
• SLOW
• TEDIOUS
• NOT USEFUL FOR
DILUTE CULTURES
ELECTRONIC COUNT
• ADVANTAGES
– RAPID
– ACCURATE IF
CELLS ONLY ARE
PRESENT
• EXPENSIVE
• CAN’T USE IF
FOREIGN
PARTICLES ARE
PRESENT
PLATE COUNT
• POUR PLATE
• SERIAL DILUTIONS
• COUNT PLATES BETWEEN 3O AND
300 COLONIES
• ADVANTAGES
– EXTREMELY
SENSITIVE
– DOES NOT NEED
COMPLICATED
EQUIPMENT
• DISADVANTAGES
–
–
–
–
SAMPLING ERRORS
TIME CONSUMING
TEDIOUS
LARGE NUMBERS
MUST BE COUNTED
TO REDUCE
SAMPLING ERROR
MOST PROBABLE NUMBER
• A SINGLE LIVE
CELL CAN GIVE
RISE TO A TURBID
CULTURE
• SERIAL DILUTIONS
• USES STATISTICAL
TABLE
• ADVANTAGES
– ALLOW COUNTS OF
MICROBES THAT
ARE DIFFICULT TO
GROW ON SOLID
MEDIA
– CAN BE USED TO
COUNT CELLS IN
MIXED LIQUID
CULTURE
• DISADVANTAGE
– TIME CONSUMING
– TEDIOUS
FILTRATION
• PREPARATION FOR
OTHER METHODS
MICROBIAL
DEATH
TERMS
•
•
•
•
•
•
•
STERILIZATION
DISINFECTION
SANITATION
DECONTAMINATION
ANTISEPSIS
MICROBIOSTATIC
MICROBIOCIDAL
RATE OF MICROBIAL DEATH
• EXPONENTIAL DEATH
• ASYNCHRONOUS
• CAN BE CALCULATED
DECIMAL REDUCTION TIME
• D VALUE
• TIME IT TAKES TO KILL 90 PERCENT
OF POPULATION
FACTORS THAT AFFECT D
VALUE
•
•
•
•
TEMPERATURE
TYPE OF MICROBE
PHASE OF GROWTH
PRESENCE OF OTHER SUBSTANCES
PROBABILITY OF
STERIZATION
• 90 PERCENT OF POPULATION DIES
• EVENTUALLY WE HAVE THE
PROBABILITY OF NO MICROBES IN
THE POPULATION
DESIGNING A
STERILIZATION PROGRAM
• D VALUE OF TREATMENT
• NUMBER OF CELLS PRESENT
• DEGREE OF CERTAINTY OF
STERILITY DESIRED
THERMAL DEATH POINT
• TDP
• LOWEST TEMPERATURE NEEDED TO
KILL ALL MICROBES IN A LIQUID
SUSPENSION IN 10 MINUTES
THERMAL DEATH TIME
• TDT
• MINIMAL TIME TO KILL ALL
MICROBES IN A LIQUID SUSPENSION
AT A GIVEN TEMPERATURE
PHYSICAL CONTROLS OF
MICROBIAL GROWTH
•
•
•
•
•
•
HEAT
COLD
RADIATION
FILTRATION
DRYING
OSMOTIC STRENGTH
HEAT
•
•
•
•
INEXPENSIVE
EFFECTIVE
DRY HEAT
MOIST HEAT
AUTOCLAVE
• USES STEAM TO STERILZIE
• MAINTAINS PRESSURE AT 103 kPa (15
PSI)
• KILLS ALL BACTERIA, VIRUSES,
FUNGI AND ENDOSPORES
– EXCEPT STRAIN 121 AND PRIONS
– DOES NOT DESTROY ENDOTOXINS
PASTEURIZATION
• DISINFECTION PROCESS
• MILK, WINES, BEERS……
COLD
• BY ITSELF DOES
NOT KILL
• COLD SHOCK
ONLY EXCEPTION
• MICROBIOSTATIC
FREEZING
• DOES KILL MOST BACTERIA
• DOES KILL EUKARYOTES
RADIATION
• ELECTROMAGNETIC RADIATION
• ULTRAVIOLET RADIATION
• IONIZING RADIATION
UV RADIATION
• WAVELENGTH OF
10 TO 400 nm
• 265 nm UV LIGHT
MOST LETHAL
• GERMICIDAL
LIGHTS
• 253.7 nm LIGHT
IONIZING RADIATION
• X-RAYS
• GAMMA RAYS
• CAUSE CHAIN OF
IONIZATIONS
• KILL CELLS
FILTRATION
• MICROBES EXCEPT VIRUSES
REMOVED
• NOT STERIZATION
• USED FOR HEAT
• LABILE MEDIA
DRYING
• EVAPORATION
• SUBLIMATION
EVAPORATION
•
•
•
•
REMOVAL OF WATER
USED FOR FOOD
SELDOM USED IN
MICRO LAB
LYOPHILIZATION
• SUBLIMATION
• DIRECT
CONVERSION
FORM SOLID STATE
TO GASEOUS
STATE
• VACUUM
OSMOTIC STRENGTH
• USED TO
PRESERVE FOOD
• SUGAR
• SALT
CHEMICAL CONTROL OF
MICROBES
TERMS
•
•
•
•
•
CHEMOTHERAPEUTIC AGENTS
GERMICIDES
GERMISTATS
DISINFECTANTS
ANTISEPTICS
SELECTING A GERMICIDE
• HIGH ACTIVITY GERMICIDE
• INTERMEDIATE ACTIVITY GERMICIDE
• LOW ACTIVITY GERMICIDE
SELECTING A GERMICIDE
• HIGH ACTIVITY GERMICIDE
• INTERMEDIATE ACTIVITY
GERMICIDE
• LOW ACTIVITY GERMICIDE
TESTING GERMICIDES
•
•
•
•
SERIAL DILUTIONS
PHENOL COEFFICIENT
PAPER DISC METHOD
USE DILUTION TEST
TYPES OF GERMICIDES
• PHENOLS , PHENOLICS &
BISPHENOLS
• BIGUANIDES
• ALCOHOLS
• HALOGENS AND PEROXYGENS
• HEAVY METALS
• SURFACTANTS
• ALKYLATING AGENTS
PHENOLS, PHENOLICS &
BISPHENOLS
• PHENOL
– CARBOLIC ACID
• PHENYLPHENOL
• HEXACHLOROPHENE
• INACTIVATE VITAL CELLULAR
PROTEINS
• PHENOLICS DISRUPT CELL
MEMBRANES
BIGUANIDES
• CHLORHEXIDINE
ALCOHOLS
• DISRUPT LIPIDS IN
CELL MEMBRANES
• DISRUPT PROTEINS
• ETHANOL
• ISOPROPANOL
HALOGENS
• OXIDIZING AGENTS
• INACTIVATE ENZYMES
• ATTACK SULFHYDRYL
GROUPS
• IODINE
• CHLORINE
PEROXYGENS
OZONE, HYDROGEN PEROXIDE
AND PERACETIC ACID
OZONE
• HIGHLY REACTIVE
• SUPPLEMENTS
CHLORINE IN
WATER
TREATMENT
HYDROGEN PEROXIDE
• OXIDIZING AGENT
• WORKS LIKE
HALOGENS
• 3% AS ANTISEPTIC
OR DISINFECTANT
PERACETIC ACID
• EFFECTIVE
AGAINST SPORES
AND VIRUSES
• FOOD AND
MEDICAL
INSTRUMENT USES
HEAVY METALS
•
•
•
•
MERCURY
SILVER
MERCURIC CHLORIDE
MERTHIOLATE AND
MERCUROCHROME
• COLLOIDAL SILVER AND SILVER
SALTS
SURFACTANTS
• HYROPHILIC AND HYDROPHOBIC
PORTIONS
• FORM EMULSIONS
• QUATERNARY AMMONIUM SALTS
• ANIONIC SURFACTANTS
ALKYLATING AGENTS
•
•
•
•
FORMALDEHYDE--FORMALIN
ETHYLENE OXIDE
GLUTARALDEHYDE
ATTACH SHORT CARBON CHAINS
INTO ENZYMES
• INACTIVATES THEM AND CELL DIES
FORMALDEHYDE
GLUTARALDEHYDE
ETHYLENE OXIDE
Microbial Characteristics and
Microbial Control
CHEMOTHERAPEUTIC
AGENTS
INTERNET RESOURCES
• http://gsbs.utmb.edu/microbook/ch011.htm
ANTIMICROBIAL
CHEMOTHERAPY
THE USE OF CHEMICALS TO
CONTROL OR PREVENT
INFECTION
CHEMOTHERAPY
THE USE OF CHEMICALS TO
TREAT, RELIEVE OR PREVENT
DISEASE
SOURCES OF ANTIBACTERIAL
AGENTS
• http://helios.bto.ed.ac.uk/bto/microbes/peni
cill.htm
• BACTERIA
– STREPTOMYCES
– BACILLUS
• FUNGI
– PENICILLIUM
– CEPHALOSPORIUM
SCOPE OF ANTIMICROBIAL
ACTION
• NARROW SPECTRUM
• BROAD SPECTRUM
INTERACTIONS BETWEEN
HOST, MICROBE, AND DRUG
• DRUG ADMINISTRATION
• DRUG ABSORPTION AND
DISTRIBUTION
• DESTRUCTION OR INHIBITION OF
MICROBE
• DRUG INACTIVATION BY HOST
DRUG ADMINISTRATION
•
•
•
•
•
PER OS
INTRAMUSCULAR INJECTION
INTRAVENOUSLY
TOPICAL
INJECTION INTO BODY CAVITY OR
SUBCUTANEOUSLY
INTERACTIONS BETWEEN
HOST, MICROBE, AND DRUG
• DRUG ADMINISTRATION
• DRUG ABSORPTION AND
DISTRIBUTION
• DESTRUCTION OR INHIBITION OF
MICROBE
• DRUG INACTIVATION BY HOST
DRUG ELIMINATION
• SOME DRUGS METABOLIZED IN
LIVER
• MOST ELIMINATED BY KIDNEYS
• PROBENECID SLOWS RATE OF
EXCRETION BY KIDNEYS
• SOME DRUGS EXCRETED BY LIVER
IN BILE AND IN FECES
MECHANISMS OF DRUG
ACTION
INTERACTION BETWEEN DRUG
AND MICROBE
SELECTIVE TOXICITY
• INHIBIT OR KILL MICROBES
• HAVE LITTLE IF ANY EFFECT ON
HOST TISSUES
MECHANISMS OF DRUG
ACTION
• INHIBIT CELL WALL SYNTHESIS
• INHIBIT NUCLEIC ACID SYNTHESIS
• INTERFERE WITH PROTEIN
SYNTHESIS
• INTERFERE WITH THE FUNCTION OF
THE CELL MEMBRANE
• ANTIMETABOLITE
• INACTIVATE ENZYMES
ANTIMICROBIAL DRUGS THAT
AFFECT THE BACTERIAL CELL
WALL
•
•
•
•
•
•
PEPTIDOGLYCAN TARGET
CELL WILL LYSE WITHOUT IT
PENICILLINS
CEPHALOSPORINS
VANCOMYCIN
BACITRACIN
PENICILLIN
CEPHALOSPORIN
VANCOMYCIN
BACITRACIN
ISONIAZID
ETHAMBUTOL
DRUGS THAT DISRUPT THE
CELL MEMBRANE
• DIE FROM METABOLIC
INSUFFICIENCY
• LYSIS
• POLYMIXINS
• POLYENES
• IMIDAZOLES
• ACTS ON LIPIDS IN MEMBRANES
• NOT AS GOOD SELECTIVE TOXICITY
POLYMIXINS
NYSTATIN
AMPHOTERCIN B
IMIDAZOLES
.
.
DRUGS THAT INHIBIT
PROTEIN SYNTHESIS
• AFFECT 70s RIBOSOME
• 30s SUBUNIT----ie. AMINOGLYCOSIDES
TETRACYCLINE
• 50s SUBUNIT----ie. CHLORAMPHENICOL
ERYTHROMYCIN
• BACTERICIDAL--AMINOGLYCOSIDES
• BACTERIOSTATIC--ALL OTHER GROUPS
STREPTOMYCIN
ERYTHROMYCIN
TETRACYCLINES
CHLORAMPHENICOL
DRUGS THAT INHIBIT
NUCLEIC ACID SYNTHESIS
•
•
•
•
LONG METABOLIC PATHWAY
TOPOISOMERASES--QUINOLONES
POLYMERASES—RIFAMPIN
FLUCYTOSINE
RIFAMIPIN
QUNINOLONES
FLUCYTOSINE
DRUGS THAT ARE
ANTIMETABOLITES
• ANTIMETABOLITES
• INHIBITION OF
FOLIC ACID
SYNTHESIS
• SULFONAMIDES
• FLUCYTOSINE
ANTIVIRAL DRUGS
• ACYCLOVIR
• AMANTIDINE
DRUGS THAT INACTIVATE
ENZYMES
• PENICILLIN & CEPHALOSPORINS
• VANCOMYCIN
EXAMPLES OF SIDEFFECTS
• TOXICITY
• HYPERSENSITIVITIES
• DISRUPTION OF NORMAL FLORA
TOXICITY
SOME DRUGS HAVE TOXIC
EFFECTS ON PATIENTS
HYPERSENSITIVITIES
•
•
•
•
SOME ALLERGENS
SOME HAPTENS
MILD TO SERVERE SKIN RASHES
ANAPHYLACTIC SHOCK
DISRUPTION OF NORMAL
FLORA
• ESPECIALLY BROAD SPECTRUM
• SKIN, DIGESTIVE, UPPER
RESPIRATORY, UROGENITAL TRACT
• CANDIDA
• SUPERINFECTION
• LACTINEX IS GIVEN TO
COUNTERACT
DRUG RESISTANCE
• ADAPTIVE RESPONSE OF
MICROORGANIMS
• RESULT OF DRUG THERAPY, GENETIC
VARIABILITY AND NATURAL
SELECTION
REASONS FOR
SUPERINFECTIONS
• OFTEN PATIENTS ARE DEBILITATED
AND HAVE LESS RESISTANCE
• THE CARE ENVIRONMENT OFTEN
HAS DRUG RESISTANT ORGANISMS
PRESENT
DRUG RESISTANCE
• GENETIC MECHANISMS
• NONGENETIC MECHANISMS
• http://images.google.com/imgres?imgurl=http://microvet.arizona.ed
u/Courses/MIC438/decker/AntibioticRes/20T02_Activity.jpg&imgrefurl=http://microvet.arizona.edu/Courses/M
IC438/decker/AntibioticRes/AntibioticResistance.html&h=361&w=
800&sz=55&tbnid=GLwmlTgTlJqRoM:&tbnh=64&tbnw=142&hl=
en&start=7&prev=/images%3Fq%3Dspectrum%2Bof%2Bantibiotic
%2Baction%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3D
G
• http://images.google.com/imgres?imgurl=http://www.wiley.com/coll
ege/pratt/0471393878/student/activities/bacterial_drug_resistance/re
sistance_transfer_web.jpg&imgrefurl=http://www.wiley.com/colleg
e/pratt/0471393878/student/activities/bacterial_drug_resistance/&h=
285&w=400&sz=27&tbnid=mH0fjM9zuN7zXM:&tbnh=85&tbnw
=120&hl=en&start=9&prev=/images%3Fq%3DDRUG%2BRESIST
ANCE%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DG
NONGENETIC MECHANISMS
• EVASION
• L FORMS
GENETIC MECHANISMS
DEVELOPMENT OF DRUG
RESISTANCE
•
•
•
•
•
•
MUTATIONS
TRANSFORMATION
TRANSDUCTION
CONJUGATION
RESISTANCE FACTORS
http://www.methylgene.com/images/gestion
/BetaLactamase.swf
MUTATIONS
CONJUGATION
TRANSFORMATION
GENERALIZED TRANSDUCTION
SPECIALIZED TRANSDUCTION
SPECIFIC MECHANISMS
• SYNTHESIS OF ENZYMES THAT
INACTIVATE DRUG
• DECREASE IN CELL MEMBRANE
PERMEABILITY AND UPTAKE
• CHANGE IN NUMBER OF AFFINITY OF
RECEPTOR SITES
• MODIFICATION OF METABOLIC
PATHWAYS
• DORMANCY
• L FORMS
MECHANISMS OF DRUG
INACTIVATION—ENZYMES
• ENZYMES THAT ALTER DRUG
STRUCTURE
• BETA-LACTAMASES
• PENICILLINASE
• CEPAHLOSPORINASE
• STAPHYLOCOCCUS AUREUS AND
NESSERIA GONORRHOEAE
• SOME GRAM NEGATIVE BACTERIA
MECHANISMS OF DRUG
INACTIVATION--ADDITION OF
FUNCTIONAL GROUPS
• AMINOGLYCOSIDES
• CHLORAMPHENICOL
• PREVENTION OF ATTACHMENT TO
BACTERIAL RIBOSOME
DECREASED PERMEABILITY
OF CELL TO DRUG
• GRAM NEGATIVE OUTER MEMBRANE
• PUMP THE DRUG BACK OUT OF CELL
CHANGE DRUG RECEPTORS
• ALTER NATURE OF DRUG’S TARGET
• ALTER PROTEINS --RIFAMPIN AND
STREPTOMYCIN
• ALTER 50s RIBOSOME--CLINDAMYCIN,
LINCOMYCIN, ERYTHROMYCIN
• CHANGE BINDING SITE IN CELL WALLPENICILLIN & METHAICILLIN
• DECREASE SYNTHESIS OF ERGOSTEROL IN
FUNGAL CELL WALL--AMPHOTERCIN B
CHANGE METABOLIC
PATHWAYS
• DEVELOP ALTERNATE PATHWAY OR
ENZYME
• SULFONAMIDE AND TRIMETHROPIM
RESISTANCE
• SHUT DOWM PATHWAY
• FLUCYTOSINE
THE ROLE OF NATURAL SELECTION IN
DRUG RESISTANCE
• OCCURS IN WHOLE POPULATION
• VARIATION IN POPULATION
• RESISTANT STRAINS MAY BE IN LOW
NUMBERS
• IN PRESENCE OF ANTIBACTERIAL AGENT
NON RESISTANT DIE
• RESISTANT FORMS INCREASE DUE TO
REPRODUCTION
• http://www.geocities.com/Heartland/7547/antibios.
html
FIRST, SECOND AND THIRD
LINE DRUGS
FIRST, SECOND AND THIRD
GENERATION DRUGS
• DRUGS THAT ARE DERIVATIVES OF
ONE ANOTHER
• MAY BE USED AS LINE DRUGS
CROSS RESISTANCE
• RESISTANCE TO TWO OR MORE
DRUGS
• BETA-LACTAMASE
NOSCOMIAL DRUG
RESISTANT INFECTIONS
• SULFONAMIDES FIRST
ANTIBACTERIAL AGENT
• FIRST TO HAVE RESISTANT SPECIES
DEVELOP
• PENICILLIN NEXT ADVANCE
• AT FIRST 95+% OF ALL STAPH.
AUREUS WERE SUSCEPTIBLE
• NOW 95+% OF ALL STAPH. AUREUS
ARE RESISTANT
EXAMPLES OF RESISTANT
SPECIES
•
•
•
•
•
STAPHYLOCOCCI
GONOCOCCI
SALMONELLA
NEISSERIA
PSEUDOMONAS
NOSOCOMIAL INFECTIONS
• SICK PEOPLE FREQUENT HOSPITALS
• TEND TO BE MORE SEVERELY ILL
• HAVE LOWERED RESISTANCE TO
DISEASE
• HOSPITALS USE LOTS OF
ANTIBACTERIAL AGENTS
HOW TO REDUCE
ANTIBACTERIAL AGENTS THAT
ARE RESISTANT NOSOCOMIAL
INFECTIONS
•
•
•
•
WASH YOUR HANDS
LIMIT THE USE OF ANTIBACTERIAL AGENTS
USE SENSITIVITY TESTS
USE ANTIBACTERIAL AGENTS UNTIL
ORGANISM IS COMPLETELY ERADICATED
• USE DRUG COMBINATIONS
DETERMINING MICROBIAL
SENSITIVIES TO ANTIMICROBIAL
AGENTS
•
•
•
•
•
DISK DIFFUSION METHOD
DILUTION METHOD
SERUM KILLING POWER
AUTOMATED METHODS
http://www.lancet.co.za/assets/pdf/news/Ant
imicrobial_Susceptibility_Tests.pdf
DISK DIFFUSION METHOD
• KIRBY BAUER
METHOD
• ZONES OF
INHIBITION
• 24-48 HOURS
• SENSITIVE
• MODERATELY
SENSITIVE
• RESISTANT
DILUTION METHOD
• STANDARDIZED
SHALLOW WELLS
• SPECIMEN
INTRODUCED INTO
BROTH AND DRUG
• 16-20 HOURS
• MINIMUM INHIBITORY
CONCENTRATION
• MINIMUM
BACTERIOCIDAL
CONCENTRATION
SERUM KILLING POWER
• PATIENT’S SERUM
• BACTERIAL
SUSPENSION
• LOOK FOR
TURBIDITY
INCREASING DRUG
EFFECTIVENESS
THE IDEAL
CEHMOTHERAPEUTIC AGENT
•
•
•
•
•
SOLUBLE IN BODY FLUIDS
SELECTIVE TOXICITY
NOT EASILY ALTERED TO TOXICITY
NONALLERGENIC
STABILITY--ABILITY TO MAINTAIN
CONSTANT THERAPEUTIC
CONCENTRATION
THE IDEAL CHEMOTHERAPEUTIC
AGENT
• FEW ORGANISMS ARE RESISTANT
• LONG SHELF LIFE
• REASONABLE COST