Exam 4 Flashcards
Aseptic means without contamination, t/f
True
What is sepsis?
Microbial contamination
What does sterilization mean?
Removal of all microbial contamination
Disinfection removed pathogens from surfaces, yes or no?
Yes
What does antiseptic mean?
Removing pathogens from living tissues.
Sanitization refers to lowering microbial counts to acceptable public health standards, t or f
True
-cide at the end of biocide refers to what?
Kills microbes
-asis refers to what?
Inhibiting, not killing bacteria
What are the two most difficult microbes to kill?
Prions and Endospores
What are the least resistant microbes?
Viruses with lipid envelopes (influenza)
Do cold temps kill microbes?
No, they become static because temp inhibits growth but doesn’t kill them
What is the temp to keep your fridge ?
40C
What are the 5 things that determine the death rate of microbes?
- Microbe characteristics (mycobacterium vs. HIV)
- Environmental conditions (if organic matter is present it is more difficult)
- Concentration of agent
- Time to exposure
- # of microbes at start
How so soaps work to remove microbes?
Physical removal
hydrophilic end binds to H2O & hydrophobic end binds to lipids to wash them down the drain
Name a method of removal of microbes that will not cause resistant bacteria.
Soap! Because soap physically picks up bacteria and removes it
What disinfectant/antiseptic works to disrupt the plasma membrane?
Alcohols, they dissolve the lipids in the plasma membrane
What disinfectant denatures proteins to remove microbes?
Phenols (Lysol)
How does UV light damage DNA to disinfect surfaces of microbes?
Copies can’t be made because DNA is damaged.
How do H2O2 and bleach work to disinfect?
Causing damage to many molecules, if H2O2 bumps into molecule it will damage it.
What are the two ways heat is a physical means to control microbes?
Dry-oven at 160c (350F) for several hours
Moist-autoclave 121C for 15min under 15psi
What are the 3 ways to pasteurize as a physical means to control microbes?
63C for 30 min (milk)
72C for 15 min
140C for 1 sec.
What is the temp and time for UHT pasteurization?
140C for 1 sec.
What is the advantage of UHT pasteurization?
Kills food spoilage microbes
What is the boiling temp?
100C
What is the major way medical waste is disposed of?
Incineration
What technique do we use in lab that is a physical means to control microbes?
Flaming (loops)
How does the fridge work as a physical means to control microbes?
40C doesn’t kill microbes but does slow down the growth, food will still spoil
How does the freezer work as a physical means to control microbes?
Minus 20C, ice crystals may form in cells and may kill them but usually not so freezer cannot be counted on to kill microbes
Which bacteria will reproduce in the freezer?
Listeria monocytogenes
What is the maximum time hamburger should be kept in the freezer?
6 months
What is the term used to refer to the removal of water?
Dessication
How does the removal of water act as a physical means to control microbes?
Dessication
Adding solutes (salts or sugars) Ex. Cured hams or jellies
How does filtration work as a physical means to control microbes?
HEPA filter
Membrane filters (used to sterilize things that can’t be heated-vaccines, antibiotics, enzymes, vitamins)
How does radiation work as a physical means to control microbes?
Ionizing radiation
UV light
What is UV light used to disinfect?
Surfaces because it doesn’t penetrate very far
How does ionizing radiation control microbes?
It’s a high energy form that uses X-rays and Gamma irradiation to cause a double strand break that is difficult for any organism to repair
How does UV light control microbes?
When UV light finds two Thymines it binds them together instead of the Adosines so DNA can’t copy and gene makes unreadable proteins
What are the 10 chemical methods of bacterial control?
Phenol compounds Chlorhexidine Halogens Alcohols Heavy Metals Ammonia Compounds Preservatives Aldehydes Gases Peroxides
How do phenol compounds work as a chemical method of bacterial control?
Cresol, phisohex, Lysol
Denature proteins
Effective against TB
How is chlorhexidine a chemical method of bacterial control?
Hibiclens
Low toxicity
Effective against spores of parasites
How are halogens a chemical method of bacterial control?
Iodine, bleach, betadine-has alcohol added
Iodine for skin
Bleach for surfaces and water
What is the best concentration of alcohol to use as a chemical method of bacterial control?
70%
What is used in newborn eyes to prevent possible gonorrhea infection from mother?
Silver nitrate
What heavy metal is uses in vaccines as a chemical means of bacterial control?
Mercury-Thimerosol
What heavy metal was added to paints as a chemical means of bacterial control?
Lead
What heavy metal is used to cut down on algae as a chemical means of bacterial control?
Copper
What species of bacteria can grow in ammonia compounds?
Pseudomonas
What 3 preservatives are added to food as a chemical means of bacterial control?
Sulfites-wine
Nitrates/Nitrites-processed lunch meat
What are the two aldehydes used as chemical means of bacterial control?
Formaldehyde
Glutaradehyde
What does glutaraldehyde preserve?
Eukaryotic cells, keeps tissues from decaying
Ex. Biopsy preservation
What gas is used as a chemical means of bacterial control?
Ethylene oxide
Not wet, so things like mattresses can be treated
What chemical is most effective as a chemical means of bacterial removal?
H2O2
Why shouldn’t you keep using peroxide after a cut has been initially cleaned with peroxide?
H2O2 won’t allow the tissues to heal, so reactive if you keep using it will damage tissues
What are silent infections?
When you don’t have any symptoms so prophylaxis happens with antibiotic therapy
What are antibiotics?
Chemicals produced by one microorganism to kill or inhibit the growth of another
What are the largest group of antibiotics?
Antibacterial drugs
Antibiotics are naturally occurring however can they also be made in the lab?
Yes, they are called semi-synthetic antibiotics
What are the largest group of antibiotics?
Antibacterial drugs
What is the difference between disinfectants, antiseptics and antimicrobial drugs?
Disinfectants are for surfaces
Antiseptics are used topically
Antimicrobial drugs are used internally
What does a broad spectrum antibiotic treat? What does it also do to normal flora?
Treats multiple types of microbes and also can kill off normal flora
Which two infections are intra cellular?
Chlamidias and rickettsias
Which antibiotic is broad spectrum?
Tetracycline
If doctor isn’t sure which type of bacterial infection you might have what will he do?
Prescribe a broad spectrum antibiotic
What does penicillin kill?
Gram positive bacteria
What are the two advantages for using narrow spectrum antibiotics?
Keep normal flora & target specific species
What is required for a narrow spectrum antibiotic to be prescribed?
Requires proper diagnosis to be sure you are treating correct species
What does chloramphenicol cause in some patients? What do doctors
Have to worry about when prescribing?
Binds to 50s and inhibits formation of peptide bond,
May end up requiring a bone marrow transplant.
What is the name of one of the narrow spectrum antibiotics?
Isoniazid
What do tetracyclines interfere with?
Protein production
What can streptomycin cause?
Deafness in those patients who are genetically predisposed
Which antibiotic used in neosporin increases the permeability of the plasma membrane in bacteria?
Polymyxin-B
Why is Polymyxin-B used topically?
Because it’s toxic to humans, we have plasma membranes in our cells like bacteria
Which group of antibiotics inhibit the synthesis of DNA/RNA?
Quinolones and rifampin
Which antibiotics inhibit metabolic pathways?
TMP/SMZ; folic acid pathway, this is a good target because we don’t have it
What is antagonism?
2 antibiotics working against each other, for example;
If tetracycline and penicillin are prescribed together, it’s ineffective. Tetracyclines shut down protein synthesis and penicillin shuts down peptidoglycan production, if no enzyme activity, no cross bridges for penicillin to stop and they won’t work.
Which two species of bacteria produce antibiotics naturally?
B. Subtilis and Streptomyces
Which two fungi produce antibiotics naturally?
Cephalosporium and Penicillum
Where are bacteria that produce antibiotics found?
In soil
Why do some bacteria make antibiotics?
To keep competition down because they have to compete for food around them, everything is competition for resources and food.
What are the three things in neosporin?
Bacitracin
Polymyxin
Neomycin
How do antibiotics work?
Need to kill pathogen, not you!
They need to cause the fewest side effects in host and highest toxicity in pathogen
Need to exploit differences between pathogen and the host
Only need to use what concentration of TMP/SMZ because they work so well when prescribed together?
10%
What % of streptococcus areus is resistant?
95%
Which drugs will cause bacteria to stop making peptidoglycan (inhibit cell wall synthesis)?
Penicillins
Vancomycin
Cephalosporins
Bacitracin
Streptococcus aureus is resistant to penicillin and methicillin, what do doctors have to prescribe then to get rid of infection?
Vancomycin
When do doctors prescribe prophylaxis antibiotic treatment?
Before surgery
Before dental work in heart patients
AIDS patients to prevent many infections
What does nosocomial mean?
Healthcare acquired infections
What does in Vivo mean?
In the body
What does in vitro mean?
Outside the body, in the lab
What factors affect antimicrobial activity?
Metabolic state of pathogen
Distribution of drug is different in different tissues
Location of pathogen
Interfering substances (low pH in stomach)
Concentration of antibiotics in body
Name the antiviral drugs.
Nucleotide analogs
Enzyme inhibitors
Interferons
What do nucleotide analogs do?
Look similar to the bases and sugars of DNA, AZT looks like thymine and acyclovir looks like guanine, they cause mistakes in the DNA
What do enzyme inhibitors do?
They are important in controlling HIV infection, reverse transcription inhibitors inhibit reverse transcription
What produces interferons?
Our bodies produce naturally, white blood cells and virus infected cells make it
What do interferons cause?
They cause symptoms of fatigue, aches, fever so we will slow down and the body can use energy to heal
What do interferons serve as?
Warning signs to surrounding cells that a virus is present
What is a good target for anti fungal drugs?
Tough because we have same type of cell structure, they have ergosterol and we have cholesterol so this is a good target
What does griseofulvin bind to to treat fungal skin infections?
Keratin in skin cells, stops bacteria from producing ergosterol
Are people antibiotic resistant?
No!! Microbes are antibiotic resistant, as they are exposed to drugs the cells that have defenses against them survive
What are the 5 defenses microbes have against drugs?
- Changes receptor for drugs so they can’t bind
- Change target site, change ribosome structure
- Bind to drug and inactivate it (penicillinase)
- Change metabolic pathway
- Produce a MDR (multi-drug resistant) pump ex. Triclosan makes bacteria make this type of pump
What are the two antibiotic sensitivity tests?
Kirby Bauer test
Minimal inhibitory concentration test
Which is the test we did in lab?
Kirby Bauer test
How does Kirby Bauer test work?
Measure zones of inhibition
Isolate pathogen, grow culture, swipe all over Petri dish agar, use paper disk w/ antibiotic in it, incubate, measure zone of inhibition, send report to doc, report doesn’t tell doc which antibiotic to use due to possible side effects in patients
How does minimal inhibitory concentration test work?
Uses 96 well plates w/ different antibiotics in the wells, inoculate and incubate, look for button growth in the bottom of the wells, if button growth goes down to roughly 10% then the antibiotic is sensitive
What do amphotericin B and imidazole do?
Affect sterol production—both stop ergosterol production
What is an epidemic?
Wide spread disease in a geographical location
Ex: could be in a nursing home or could be the entire US
What is a pandemic?
Wide spread disease throughout the world
Ex: AIDS, influenza
What is an endemic?
A low number of cases in a geographical location over a long period of time.
Ex: every year there are a few bubonic plague cases in the southwest
What is MERS?
Less than 2 yrs ago, 30% mortality, from the corona virus family, crossed over into humans from camels in the Middle East
What is mortality rate of the Ebola virus?
67%
What does immunology mean?
Specific defenses are for particular pathogens
What does susceptibility mean?
Lack of resistance to a disease
What is immunity?
Ability to fight off disease
What is innate immunity?
Built in defense, born with it
What are the 7 non-specific defenses of the host?
Skin & mucous membranes
Physical barriers
Chemical defenses
Normal flora
Phagocytic cells
Inflammation
Fever
How do skin and mucus membranes protect the host?
Epithelial cells
Waterproof yet elastic
Produce mucus to trap microbes
What do goblet cells make?
Mucus
How does whooping cough cause disease?
Bacteria paralyzes cilia causing coughing and gasping for breath
What is cilia escalator?
Microbes trapped in mucus are best out by cilia
What are the non-specific physical barriers that protect the host?
Lacrimal apparatus-tears Saliva Urine Vaginal secretions Hairs Ciliates cells/mucus
What are the non-specific chemical defenses to protect the host?
Lysozyme Gastric juice Digestive juice Stomach pH Sebum/wax Perspiration Transferrins Complement Interferons
What is pH of stomach?
1-3
What is pH of skin and va jay jay?
3-5
The pH of the va jay jay is 3-5 during what period of life?
Puberty to menopause
What is released on skin during perspiration?
Salt
What do transferrins do?
Protein that binds excess iron in blood to prevent bacteria from using iron
What is complement?
Series of proteins that breakdown in the presence of pathogens to enhance the immune system
What are the 5 characteristics of inflammation?
Heat Swelling Pain Redness Loss of function
What is the purpose of inflammation?
- Destroy pathogen
- If not, wall off pathogen
- Repair tissues
What is normal body temp?
37C set by hypothalamus
What does the increase of body temp do?
Destruction of pathogens and enhancement of immune response
What are the two specific defenses to protect the host?
Humoral immunity
Cellular immunity
What do B cells make?
Antibodies
What do antibodies bind to?
Specific antigens
What are antigens?
Any type of molecule that illicits an immune response
B cells make what type of cells in case pathogens come back for a second time?
Memory cells
Which T cell is a killer?
CD8 cytotoxic T cells
Which T cell is a communicator?
CD4 helper T cells
Which T cells are the facilitators and THE communicators of the immune system?
Helper T cells-CD4
If HIV knocks out T cells then the immune response is…..
Diminished
What is the idea behind immunization ?
B cells make memory cells after immune system is challenged by vaccination or pathogen
If a person is exposed to a pathogen for the 2nd time, what will the response be?
Response is greater and faster
What occupation is the most at risk for occupation acquired HIV infection?
Nurses, 24 documented cases
What is the rate of HIV transmission to newborns?
20% without Anti-viral meds, 1% with meds
What should the CD4 counts be?
350-500
