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% of organisms grown in pure culture and why is that significant?
1% and significant b/c 99% are unknown to biologists and knowlege is limitted
how is agar made?
polysacharide derived from marine alga, and used as thickener in foods
why agar suitable to grow microbes? temperatures at liquid and solid states?
- few microbes degrade agar, so it remains solid.
- liquifies at 100 degrees C (boiling point of water) and remains liquid until 40 degrees C.
free of living organisms
procedure to minimize unintentional introduction of microorganism
Minimum/optimum/maximum temp range for psychrophiles?
- -100 celcius to 200 celcius
- optimum 150
Minimum/optimum/maximum temp range for pschrotrophs?
- 00 celcius to 300 celcius
- optimum 250
Minimum/optimum/maximum temp range for mesophils?
- 100 to 500 celcius
- optimum 250
Minimum/optimum/maximum temp range for thermophils?
- 400 celcius to 700 celcius
- optimum 550
Minimum/optimum/maximum temp range for hyperthermophils?
- 650 celcius to 1100 celcius
- optimum 800
why does growth stop at the min and max temperatures?
- protien denatures
- membrane fluidity
what is osmotic pressure and give example?
- amt of pressure in concentration of solute in a soln.
- example---> water goes where increased salt/sugar is so pressure pushes more water in that direction to dilute it.
how osmotic pressure effects microbe growth?
high salt/sugar draw water out of cells and rpevent growth.
why microbes require carbon?
growth- needed for all living cells
why microbes need sulfur?
why microbes need nitrogen?
- synthesis of DNA/RNA
- from amino group of amino acids of protiens
trace elements? cofactor? why are they important?
- trace elements = cofactors
- cofactor are inorganic particles that are required for the fxn of other elements.
organism require oxygen to live
organism that continue to grow in absence of oxygen
organism unable to use oxygen for reactions needing energy.
organism taht cant use oxygen for growth, but tolerate it
organism that require oxygen (aerobic)
4 phases of microbial growth curve
- lag phase- prepare for population growth, but no increase in population (little to no cell division)
- log phase- logarithmic/exponential increase in population as cells begin to divide
- stationary phase- equilibrium (death = # of cells produced)
- death phase- population decrease at logarithmic rate. number of deaths is greater then new cells formed.
gram stain is old... how would it look?
communities of microbes reside in matrix made up of polysaccharide that contain DNA adn protien
absence of significant contamination
destruction of all forms of microbial life, including endospores with possible exeption of prion
heat tx to kill endospores of botulisum in canned food
destruction of vegatative pathogens
destruction of vegatative pathogens on livign tissues
removal of microbes from limitted area, such as skin around injection site
tx intended to lower microbe count on eating utensils
death of microbe
inhibit growth/multiplication of bacteria
nosocomial infections? why are they higher then norm rate?
hospital acquired infection r/t patient vulnerability/low immune system and invasive procedures done
how to control nosocomial infections?
- aseptic technique
- handle contamination careful
- insist of frequent and good hand washing
decimal reducation time and how measured?
- r/t heat resistance adn is the time in minutes in which 90% if bacteria will be killed at given temp.
- measurement---> 1 log decrease = 90% population killed
critical items? give examples
- critical items puncture tissues
- examples: needle, stitch, scalpel, knife, razor
semi critical items? examples?
- come in contact with mucous membranes
- examples: oral thermometer, foley cath, nasal spray, inhaler, speculum
non critical items? examples?
- come into contact with unbroken skin
- examples: stethoscope, bp cuff, pulse ox, sun tan bed surface, stop watch
3 types of heavy metal that have antimicrobial action?
- copper (Cu)
- mercury (Hg)
types of food preservation?
- organic acid
- sorbic acid, benzoic acid, calcium propionate
- gaseous sterilant
why calcium proprionate is used as food preservative ?
inhibit metabolism, control mold and bacteria
contributions of paul erlich?
1910 discovered salvarasan, arsenic compound. came up with using chemicals to tx infection
contribution of alexander fleming?
1928 left lab dirty adn mold grew on open petri dish, lead to discovery of penicillin, which led to first clinical trials
contribution of gerhard domagk?
1932 discovered sulfa drug effective for sex transmitted disease
contribution of ernst chain/howard florey?
1941 penicillin purified and avail after WW 2
any chemical or drug used to treat disease
interfere with growth of microbes within host
substance produced by microorganism that in sm amt inhibit another microorganism
drug that kills harmful microbe without damage of host
drug used to tx protozoa or malaria?
drug used to tx fungi
drug used to tx helminth?
- niclosamide (tape worm)
- praziquantel (flukes)
drug used for tx of virus?
drug to tx gram (+) bacteria?
drug to tx mycobacterium ONLY? (TB)
drug to tx mycobacterium AND gram (-) bacteria?
drug to tx gram (-) and gram (+) bacteria AND Chlamydia/Rickettsia?
tetracycline (most broad spectrum)
how penecillin works?
Inhibit cell wall synthesis
how cephalosporin effect microbes?
inhibit cell wall synthesis as penecillin but formed slightly different which makes more effective agains more gram (-) bacteria then penecillin
why vancomycin important?
only tx still works for MRSA
what is MRSA and what is tx?
- Methicillin resisistant Staphylococcus Aureus that is resistnat to antibiotic methicillin adn most other antibiotics.
- IV vancomycin is only tx left that is still effective
how drug resistance develop?
- mutations can lead to resistance
- misuse of antibiotic
therapeutic effect of 2 drug given together is greater then if given either drug alone
simultaeous use of 2 drugs has less effect then if either drug taken alone
antibiotic that is bactericidal AND broad spectrum of activity
complementary DNA or peptide nucleic acid that bind to pathogens gens and prevent transcription
virus that infects bacterial cells
submicroscopic, parasitic, filterable agent consist of nucliec acid surround by protien coat
complete fully developed viral particle
2 ways virus attach and infect cells?
- lysogenic- cell replicates and host cell remains alive
- lytic- ends with lysis and death of host cell
viral taxonomy rules?
- family names end in - viridae
- genus name end in- virus
- common name used for species
- subspecies designated by number
2 ways virus grown in lab?
- embryonated egg- hole drilled in shell adn virus injected in flud of egg. viral growth seen by death of embryo, embryo cell damage or formation of pocks/lesions on egg membranes
- cell culture- treat slice of animal tissue with enzymes that seperate individual cells. these cells suspended in soln adn normal cells will adhere to glass/plastic container adn virus will infect monolayer causing celsl to deteriorate as they multiply.
ways virus are identified?
- cytopathic effect- visible effect of viral infection (s/s of pt)
- serological tests- virus detected and identified by its reaction with antibiotics by using specific testing
stages of bacteriophage multiplication?
- attachment: phage attach by tail fiber
- penetration: phage lysozyme opens cell wall and tail fibers contract and force tail core and DNA into cell
- biosynthesis: production of DNA and protien
- maturation: assembly of phage particle
- release: phage lysozyme breaks cell wall (lysis)
stages of animal virus multiplication?
- attachment: virus attach to cell membrane
- penetration: endocytosis/fusion
- uncoating: viral or host enzyme
- biosynthesis: prodution of viral genetic material/protiens
- maturation: viral particle assembled
- release: budding (enveloped) or cell lysis
Lytic cycle in detail
- attachment: chance collision between phage particle and bacteria and attachment site on virus attaches to complementary receptor site on bacteria
- penetration: after attachment, bacteriophage injects DNA intio bacteria. the tail releases an enzyme which breaks down a portion of bacterial cell wall. the tail contracts and core is driven through cell wall.
- biosynthesis: DNA reaches cytoplasm of host cell and biosynthesis of viral nucliec acid and protien occurs. host protien synthesis stops. Phage uses host cell to make many copies of DNA. biosynthesis of viral protien then begins and RNA transcribed in cell as mRNA.
- maturation: bacteria DNA and capsid assembled into complete virion. this happens simultaneously eliminating need for nonstructural genes and gene product. the phage head/tail are seperated from protien subunit and head filled with DNA and attached to tail
- release: realease from host cell. plasma membrane breaks open (lysis) and lysozyme causes bacteria cell wall to break down and release from host cell. it infects other susceptible cells and then multiplies with those cells
lysogenic cycle in detail
- attachment: phage attaches to host cell and injects DNA
- penetration: phage DNA circulizes adn enters lytic cycle or lysogenic cycle. the original linear phage DNA forms circle adn can multiply adn be transcribed leading to production of new phage adn cell lysis (lytic cycle)
- in lysogenic cycle: circle can recombine adn become part of circular bacterial DNA (lysogenic cycle) the inserted DNA how are repressed by 2 repressor protien. they stop transcription of all other phage genes by binding to operators.
- every time host cells machinery replicates bacteria chromosome also replicates prophage DNA. (remains latent in progeny cells)
- in some cases: spontaneous event/action of UV light/chemicals cause popping out of phage DNA and initiation of lytic cycle
latent viral infection
equilibrium virus within host and doesnt' produce disease for long periods of time (herpes virus)
persistant viral infections?
chronic viral infections that occur gradual over time (fatal)
double strand DNA non envelope virus?
- masadenovirus (resp infect in hman/tumor in animal)
- paillomavirus (human warts)
double strand DNA envelope virus?
- poxviridae (small poz/vaccinia virus)
- herpesviridae (chicken pox/shingle/fever blister)
- hepadnaviridae (hep B)
single strand DNA non envelope virus?
- human parvovirus
single strand RNA + stand non envelope virus?
- picornaviridae (enterovirus- polio/coxsackie)(rhinovirus)
- caliciviridea (hep A/norovirus)
single strand RNA + strand enveloped virus?
- togaviridae- (equine encephalitis/rubella)
- flavaviridae- (west nile/yellow fever)
- coronaviridae- (cold/SARS)
infectious protien inherited adn transmitted by ingestion, transplant adn invasive procedure
problem with storing pure culture?
- freezing- still can grow/kills sample as ice crystal can rip apart cells d/t water in it
- lyophiliztion- freeze drying is best mode to store pure culture as it takes out water adn results in powder
- slants- dry out if put in incubator
introduce microbe into medium
microbes growing in/on medium
encourage growth of specific microbe by isolation with specific characteristics from heterogenous population
things effect tx of microbe death?
- # of microbes
- time of exposure
- microbial charateristic
how antimicrobial agents work?
- alter membrane permeability
- damage protiens
- damage nucliec acid
how heat used to control microbes?
- boiling- fast, cheap reliable (doesnt kill endospores)
- pasterization- decrese number of microbes
- pressureized steam- achieve temp above 100 degrees celcius to destroy endospore (autoclave)
- dry heat (open flame)- high temp for long length
how radiation disinfect
how osmotic pressure control microbes?
desiccation to control microbes?
how soap effective for disinfect?
how acid anionic detergent disinfects?
how QUATS disinfect?
- denature protiens
- disrupt plasma membrane
effective against endospore?
- chlorine (fair)
- glutaraldehyde (fair)
effective against mycobacteria?
- phenolic (good)
- chlorine (fair)
- alcohol (good)
- glutaraldehyde (good)
- DNA/or RNA
- protien coat
- some enclosed in envelope
- some spiked
- only infect specific type of cells in 1 host
- virus particle
- capsid is protien coat surround nucleic acid
- capsid made up of individual protien capsomers
- virion particle is protien, nuclieic acid (nucleocapsid)
- non enveloped virus = naked
- helical- long rod looking
- polyhedral- 20 triangle faces with 12 corners
- complex- combination of above
mulitplication of retrovirus (RNA virus)
inject RNA to make DNA and back to RNA (backwards)
- sheep scrapie
- mad cow disease
varicella zoster virus
- chicken pox, human to human, respiratory droplets, skin lesions start on torso and spread to arms/legs
- tx- acyclovir
- Mono, shed in oral secretions of asymtomatic adult
- fever, sore thraot, lymphadenopathy
- tx- rest , fluid NO ANTIBIOTIC
- human infect via aerosolized rodent saliva or urine
- mild fever, follow by acute resp distress syndrome
- to tx
- severe acute resp syndrome
- srpead by aerosolized droplets
- fever, follow by 3-4 days of dry cough, trouble breathing
- chest xray to confirm
- tx- supportive care, prevention
- spread by aerosolized resp secretions
- high fever, head ache, myalgia, rhinorrhea, uncomfortable night sweat, ache,
- infect resp epithelium and kill host cell as it replicates.
bird flu (H5N1)
- resp secretions from another infect person (inhalation/contact with infect object)
- virus kills resp mucosa cells
- tx- symmetrel, relenza, tamiflu
- 2 forms-( low patho)- undetected with mild s/s (high patho) spread rapid
- jumped species and gone from bird to human
- little to no immune protection
- s/s- fever, cough, sore throat, muscle ache, (serious) eye infection, pneumonia, resp distress
what is bird flu?
- small group of virus (orthomyxovirus/influenza)
- surface of virus covered with priotien (heamagglutinnin and neuraminidase)
- H protien attaches
- N protien let virus get out of infected cell (cant reproduce without H and N protien)
- influenza A from pig
- pig got 2 pig flu/1 human flu/1 bird flu all at same time
- s/s- regular flu but with GI s/s and more severe----> fatigue, headache, sore throat, nasal congest, vomit, diarrhea, nausea
- transmit from cough/sneeze and by touch
- tx- rest , fluid, manage fever, resistant to antiviral drug
- rhinovirus 50%
- coronovirus 15-20 %
- tx- vaccine ineffective
herpes simplex virus
- spred by contact with infected skin or mucous membrane
- HSV1- oral
- HSV2- genital
- tx- acyclovir
- virus replicate in epithelium adn infect nerve ending
- poliovirus transmited by ingestion
- s/s- sore throat, nausea
- attacks brain stem and cant control body movement
- tx- vaccine prevention
- animal bite transmission
- infect skeletal muslce then brain cell causing encephalitis
- s/s- msucle spasm of mouth/throuat, hydrophobia
- tx- (post) vaccine and immunoglobulin (pre) inject of human diploid cells vaccine
- types- (furious rabies) animal hightly exciteable (paralytic)- animal unaware of surrounding
ebola hemorrhagic fever
- severe fatal disease
- animal borne (bats)
- spread by body fluid /body fluid contact
- s/s- fev er, headache, muscle and joint pain, sore throuat, weakness, diarrhea, vomit, stomach pain, rash , red eyes, hiccups, internal /external bleed, (bleed out)
- tx- fluid, electrolyte, oxygen, bp, prevent complications
- human papillovirus
- more then 150 strains
- 30 sexually transmitted
- 15 classified as high risk
- some cause abnormal paps
- transmission- genital contact, carriers unaware, can pass to baby
- link to cervical cancer
- vaccine- gardisiland 98 % effective for male and female