microbial nutrition, growth, measurement, and control
TRANSCRIPT
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/KimballLinks.html
• http://science.nhmccd.edu/Biol/microbio.html
• http://science.nhmccd.edu/BioL/animatio.htm
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.ohio-state.edu/~sabedon/campbl27.htm#photoheterotroph
NUTRITIONAL TYPES• PHOTOAUTOTROPHS• CHEMOAUTOTROPHS• PHOTOHETEROTROPHS• CHEMOHETEROTROPHS• http://72.14.203.104/search?
q=cache:EkMmMJD4ZtIJ:rcw.raiuniversity.edu/biotechnology/BTechbiotech/microbesandus/lecture-notes/lecture-10.pdf+microbial+nutrition+chemoheterotroph+photoheterotroph+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:sclpkxyy_VMJ:www.homepage.montana.edu/~umbls/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:3iUlq0IL7tsJ:meetings.copernicus.org/egu2005/download/EGU05-J-11198-1.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:3iUlq0IL7tsJ:meetings.copernicus.org/egu2005/download/EGU05-J-11198-1.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/MicrobialLife05.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.mcgraw-hill.com/sites/0078664276/student_view0/unit1/chapter4/check_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.html
SAPROPHYTE VS PARASITE
• SAPROPHYTE USES DEAD ORGANIC MATTER
• PARASITE USES LIVING HOST
MICROBIAL NUTRITION
• http://www.mansfield.ohio-state.edu/~sabedon//biol2015.htm
• http://www.agen.ufl.edu/~chyn/age4660/lect/lect_02/lect_02.htm
MACRONUTRIENTS
• NEEDED IN LARGE AMOUNTS• CARBON• HYDROGEN• OXYGEN• NITROGEN• PHOSPHORUS• SULFUR• http://www.biologie.uni-hamburg.de/b-online/
library/micro229/terry/229sp00/lectures/nutrition.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_Interest/Biochemicals/Enzyme_Explorer/Cell_Signaling_Enzymes/Superoxide_Dismutase.html
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/
dfthiognf.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 MEDIAADENINE THYMINE
EUTROPHIC VS OLIGOTROPHIC ENVIRONMENTS
EUTROPHIC ENVIRONMENTS
• ABUNDANCE OF NUTRIENTS
• NO LIMITING FACTORS
• CULTURAL EUTROPHICATION
• http://www.umanitoba.ca/institutes/fisheries/eutro.html
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/Microtextbook/index.php?
module=Book&func=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_diffusion
• http://web.mit.edu/esgbio/www/cb/membranes/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/symport.htm
ANTIPORT
• http://bio.winona.msus.edu/berg/ANIMTNS/ANTIport.htm
• http://www.brookscole.com/chemistry_d/templates/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/courses/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
• Pseudopods extend to form phagosome
• Lysosome joins it
• No pseudopods form• Nonselective drinking of extracellular
fluid
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/ANIMTNS/Secrtion.htm
IRON UPTAKE
• USED FOR CYTOCHROMES AND ENZYMES
• FERRIC IRON INSOLUBLE
• SIDEROPHORES
MEDIA USED IN LABORATORY CULTURE
http://www.life.umd.edu/classroom/bsci424/BSCI223WebSiteFiles/Chapter6.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_resources/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 1O2-
• HYDROGEN 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
MICROBIALGROWTH
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 PHASEC 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/faculty/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|
RAPIDITY
REPRODUCIBLE
• DISADAVANTAGES
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/penicill.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.edu/Courses/MIC438/decker/AntibioticRes/20-T02_Activity.jpg&imgrefurl=http://microvet.arizona.edu/Courses/MIC438/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%3DG
• http://images.google.com/imgres?imgurl=http://www.wiley.com/college/pratt/0471393878/student/activities/bacterial_drug_resistance/resistance_transfer_web.jpg&imgrefurl=http://www.wiley.com/college/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%2BRESISTANCE%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 WALL-PENICILLIN & 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/Antimicrobial_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