High temperature effect on microbial growth
microbicidal
denature enzyme
Destroy lipids that make up membrane
Low temp effect on microbial growth
microbistatic
slow growth of cell,
reducing rate of chemical reaction
Reducing fluidity of cell membrane
Cardinal temperature
Min optimum and max temp for particular bacteria species
Psychrophile
-5C to 20C
cold arctic
Psychrotroph
0C to 35C (below optimum temp)
Mesophile
10C-50C
better at 20-40
thermophile
45C-80C hot
composting organic material/ hot springs~
Hyperthermophile
>70C
extremee thermophile
archaea
very hot
Thermus aquaticus obligate thermophile
hot water
70C thrive
50C below die
High temp denature enzyme
true
high temp destroy lipid
T
mesophilic able to grow at 4 C
psychrotroph
Min, optimum and max of S marcescens
5, 37, 40
Red = prodigiosin at 25C
Min, optimum and max of E coli
4, 37, 45
Min, optimum and max of G stearothermophilus
40, 50, 80
How to calculate absorbance on spectrophotometer
A=2-log(%T)
PH formula
pH = -log 10[H+]
0 to 14 below 7 is acidic
Water PH and H ions
10^-7 moles/L of hydrogen ion
PH 7
neutral
change in one PH represent
10 fold increasing or decreasing in hydrogen ion
PH 8 is 10 times more basic than PH 7
bacteria keep internal PH near__ regardless of outside
neutral
bacteria keep internal PH near__ regardless of outside cuz __ are easily damaged by PH
neutral, enzyme
if enzyme can't counter outside PH
denature
limit atp production
__ added to media to stabilize ph
buffer
V. parahaemolyticus (gastroenteritis) is a .... and grows in what temp
mesophile grow in 16C
as concentration of hydrogen ion increases, PH
decreases, more acidic
PH scale what is basic and acidic
0-14
below 7 acidic
above 7 basic
Neutrophil favor PH
5.5-8.5
acidophile favor ph
below 5.5
alkaliphile favor ph
above 8.5
how many more acidic is ph 7 than ph 9
100X
each change in PH is 10 X
Growth of Ecoli, A. faecalis, and T. keyfir under 5, 7, 9 PH
Ecoli optimum growth is 7
A. faecalis optimum growth 9
T keyfir optimum growth is 5 then drops
What environment does clostridium botulinum endospore like?
anaerobic ph higher than 4.6
most abundant component of cytoplasm
water!
Water act as a ____for chemical reaction and serve as a source of ___
solvent, hydrogen ion
How water travels
down their concentration gradient
low solute to high solute
Osmosis
diffuction of water across cell membrane
Pressure created by flow of water into cell
osmotic pressure
usually inside of cell has ___ concentration of solute than outside, so water
higher, rush in
aka hypotonic
Hypotonic
high solute inside cell
increase osmotic pressure
water flow in
What stops cells from lysing due to water pressure
cell wall
isotonic
solute outside is same as inside
water cross equally, no net movement
hypertonic, water flow__, what happens to cell
solute outside is greater
water go out
plasmolysis, flat
irreversible damage to enzyme
majority of bacteria grow best at salt level
0.9% to 1.0%
aka inside me!
Ecoli, S aureus, H salinarium in 0.5%, 5%, 10% and 25% Nacl
E coli- grow only 0.5 and 5% salt
S. aureus grow on 0.5, 5, 10% salt
H salinarium grow only on 25% salt
Solute vs solvent
solute- dispersed in solvent
Ham is 6% nacl, what bacteria is expected?
S. aureus, falculative halophile
Vibrio vulnificus
consumption/ contact with opem wound of uncooked shellfish
brackish water low salinity and warm
Gamma rays and X ray length
short wavelength <0.00001-100 nm
ultra violet wavelength UV-A, UV-B, UV-C
100-380 nm long
UV-A 315-400nm
UV-B 280-315nm
UV-C 100-280 nm 254nm*
Electromagnetic radiation works by
interacting with DNAand breaking down water to form highly reactive free radical
Exposure of UV-C result in, most effective wavelength is
pyrimidine dimers, 254nm
pyrimidine dimers,
254nm
covalent bond
T-C, C-C, T-T
distort DNA , death
Growth of B megaterium and S aureus after UV
B megaterium still some after 45 min
S. aureus no growth after 10 min
cryptosporidium parvum
resistant to chlorine but not UV light
Normal microbiota of skin can be divided into
Diphtheroids
Staphylococci
Yeast and fungi
Diphtheroids of normal microbiota
propionibacterium acnes
anaerobic bacteria- on hair follicle that break oily secretion
staphylococci of normal microbiota
non pathogenic
beneficial- compete and fight with pathogen for nutrients
ex. S.aureus
Yeast and fungi of normal microbiota
non pathogenic, digest oily emission of secretory gland
Transient bacteria
temporarily, depends on hygiene
varied in form: gram - and +, rod, cocci, spore, vegetative
Handwashing dilution factor
Average similar # X
1/volume = dilution factor
=organism/ml
Optimum hand washing time for surgery
7 min
Antibiotics
chemical substance from microorganism that can inhibit or kill another microbe even in a minute amount
overuse of antimicrobics has led to
resistant strain of bacteria that are immune to substances
susceptibility testing and 2 goals
identify effective chemotherapeutic agent
kill only pathogen and leaving other alone
appropriate therapeutic dose
selective toxicity
kill only pathogen while leaving other unaffected
disc diffusion
bacteria is spread on the plate discs of antimicrobics
high level near disc
Zone of inhibition is dependent on
molecular weight of antimicrobic, type of medium, concentration of bacteria culture
Kirby- bauer standard
medium: Mueller Hinton II 4 mm
bacteria culture 0.5 Mcfarland standard turbidity
Sensitive and resistant zone of inhibition
sensitive= large zone of inhibition, good drug
resistant= small zone, bacteria is resistant to drug
what information is not provided by the Kirby-Bauer test and know two ways could be obtained.
MIC- minimal inhibitory concentration(lowest level of chemical that inhibit drug
Tube dilution- single antimicrobic drug
Etest- read where inhibition ellipse intersects scale
What do many bacterial strain now require to identify effective chemotherapeutic agent
susceptibility testing
klebsiella
carbepenem-resistant enterobacteriaceae
wide rage antibiotic resistance
how to calculate therapeutic index
toxic does/MIC minimal inhibitory concentration
low is good
Who tracks data related to infectious disease
Center for disease control and prevention CDC
Notifiable disease and where to find this info
76 serious disease docs need to tell CDC
Morbidity and Mortality weekly report MMWR
online: National notifiable disease weekly tables
Morbidity
# cases per period/ susceptible population at mid point X K
whole #
Mortality:
# disease related deaths per period/# people with the disease
Incidence
# new cases/ at risk population at mid point
3 common epidemiological measurement
morbidity, mortality, incidence
Genotype & Phenotype-
Genotype- combination of genes it possess
Phenotype- appearance. Ability to utilize lactose, produce cell wall, withstand drugs
Conjugation-
DNA transferred from one bacteria to another through pilus
Transduction-
bacteriophage transfer small DNA from lysed bacteria to another of same species
Transformation
bacteria receive small amount of DNA from environment
four areas of interest in a typical plasmid what each of these areas does.
Origin of replication- sequence of DNA that is recognized by enzyme and ensure plasmid will be replicated
Drug resistance- usually ampicillin, ensure cell with plasmid will survive in antibiotic containing medium
Gene of interest- gene to be expressed, vary depending on transformation
Promotor- genetic switch allowing gene to be transcribed
Constitutive promoter- gene is transcribed at all times
Inducible promote allows gene to be transcribed only when specific condition(nutrient) exist
important aspects of the transformation process
Green fluorescent protein(GFP)- fluoresces under UV light. Used to determined if transformed gene is being transcribed
Plasmid (pGLO)- vector to intoduce GFP gene in Ecoli
DNA binding protein (AraC)- regulates arabinose promotor./ transcription. If arabinose not present, this prevent RNA polymerase from binding to arabinose promotor
B-lactamase gene(bla)- hydrolyze B lactam antibiotics (ampicillin)
Origin of replicaiton(ORI) allow plasmid to be recognized and replicated by DNA polymerase within cell
arabinose operon
When arabinose is in environment, it binds to ARAaC and allows RNA polymerase to mind to promotor and transcribe GFP producing MRNA that produces green protein
Origin of replication on plasmid
sequence of DNA that is recognized by enzyme and ensure plasmid will be replicated
Drug resistance- on plasmid
usually ampicillin, ensure cell with plasmid will survive in antibiotic containing medium
Gene of interest- on plasmid
gene to be expressed, vary depending on transformation
Promotor on plasmid, 2 kinds
genetic switch allowing gene to be transcribed
Constitutive promotor- gene transcribed at all times
inducible promotor- gene to be transcribed only when specific condition exise
Transcription of GFP gene is controlled by
when arabinose is in environment, arabinose promotor allows it to bind to AraC which allows RNA polymerase to bind to promotor and transcribe GFP creating mRNA
bla = resistance to ampicilllin
increase efficiency of transcription
making cell competent - treat it with Calcium
neutralize neg charge
Transformation efficiency
# colonies/
volume DNA * concentration DNA*fraction on plate
-troph and obligate
troph: grows across wide temp range
obligate: stick to specific temp
halophile
grow in high salt environment
halotolerant
can withstand high salt without adverse effects
-phile
love
osmophile
grow in high sugar concentration
resident microbiota
deep stable microbiota
penicillin
naturally occuring and synthetic antibiotics produced by penicillium mold and active against bacteria
bacitracin
antibiotic that target cell wall
by bacillus subtilis
antimicrobics or antimicrobials
special class of compounds capable of destroying or inhibiting microorgansim
epidemiologist
frequency, distribution, transmission of infectious disease
plasmid
small circular DNA
sporadic
disease at irregular interval in unpredictable geographic locaion
endemic
disease continuously at one region
epidemic
sudden outbreak in community
pandemic
disease affecting increased population