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212 Test 3
Question | Answer |
---|---|
Definition of "clean" | free of dirt of filth |
Definition of Disinfections | a process whereby the number of pathogenic microbes is reduced |
With disinfects, ___ are generally killed but ___ may survive | vegetative cells, spores/resistant cells |
Definition of "antiseptic" | agent used on living tissue to inhibit pathogen growth |
Definition of "sanitize" | agent used to disinfect and clean objects |
Definition of "sterilization" | process whereby all microbes have been killed-- including spores and resistant structures |
-static | inhibits growth of a microbe |
-cide | kills |
3 methods of evaluating chemical antimicrobics | phenol coefficient, filter paper method, use-dilution method (AOAC) |
Phenol coefficient | ratio of (lowest dilution of agent that kills) to (lowest dilution of phenol) with same activity) |
P.C. is best if used for... | phenol derived agents |
Test Agent 1/1000. Phenol 1/100. What is the P.C.? | 10. (Agent is 10x better than phenol) |
Filter paper method | measures zone of inhibition around soaked discs in agar plate |
Microbes typically used with P.C. | Staph. aureus and Salm. typhi |
Used with the Use-Dilution method | Staph. aureus, Salm. typhi, and Pseud aeruginosa |
What is the Use-Dilution Method (AOAC) | Stainless steel cylinders with dried microbe soaked in agent, rinsed, and cultured |
Satisfactory use-dilution level | 95% confidence level of killing |
Quality of detergents that allow emulsification | hydrophobic and hydrophillic ends |
"Quats"...aka... | quaternary ammonium compouds, a type of detergent. ex) Zephiran Chloride |
2 actions of cationic detergents | disrupt membranes and denature proteins |
Detergents are ineffective in ___ due to ___ | hard water, minerals |
Detergents originally used for ___ but ___ grows in it | Staph, Pseudomonas |
Chemical disinfectant presently used for food utensils and skin antiseptics | Detergents |
Heavy metals are generally ___-static | bacteriostatic |
Heavy metal used as an eyewash to protect newborns against gonococci | 1% Silver Nitrate |
Erythromycin replaced ___ because of ___ | 1% Silver Nitrate, Chlamydia |
Meaning of tincture... | alcohol |
Obsolete heavy metal | Tincture of merthiolate. alcohol plus mercury compound. alcohol probably active agent |
___ is a type of heavy metal used in shampoos to control dandruff which can be caused by ___ | Selenium sulfide, yeast |
3 mechanisms of action of halogens | oxidize proteins, disrupting membranes, inactivating enzymes |
halogen used in pools, drinking water, food, and dairy industry | Chlorine- hypochlorous acid |
halogen effective in killing bacteria and inactivating viruses but not spores | Chlorine- hypochlorous acid |
CDC recommends 1:10 dilution of household bleach to disinfect for HIV. Which halogen is involved | Chlorine- hypochlorous acid |
A halogen used by campers to disinfect water. Does not destroy cysts of Entamoeba histolytica | Halazone |
Early antispetic, effective but toxic to skin and left stain-- causing allergies | Iodine |
Introduced when Iodine was stopped, used more often | Iodophors |
Mechanism for Iodophors | Iodine combined with organic carrier molecule. Iodine is released slowly |
An iodophor commonly used in clinical situations, destroys fungi, protozoa, some viruses, and bacteria. Used on skin before incisions or on wounds | Betadine |
2 actions of alcohol | denatures proteins and dissolves lipids |
2 alcohols that are effective antiseptics | Ethyl and isopropyl |
High concentration of alcohols are not effective because... | evaporation |
Alcohols kill ___ but not ___ | vegetative cells, spore/resistant cells |
2 actions of phenols | denature proteins and disrupt cell membranes |
3 advantages of phenols | tuberculocidal, effective in presence of organics, remain on active on surface for long time |
2 disadvantages of phenol | disagreeable odor and skin irritation |
Lysol is a type of ___ | phenol |
Lysol aka | orthophenylphenol |
Used on fomites because it leaves a long acting film | Lysol |
Phisohex aka ___ used on skin to limit ___ | Hexachlorophene, Staph |
Reason why Hexachlorophene was discontinued | it is absorbed into skin, potentially causing neurotoxicity in newborns |
Phenol used to limit ___ on skin, not absorbed into skin | Hibiclens/Chlorohexidene, Staph |
Hydrogen peroxide formation | superoxide radical formed during generation of oxygen gas |
2 actions of hydrogen peroxide | inactivate proteins and disrupt membranes |
once though to have a deleterious effect on anaerobes | hydrogen peroxide |
mechanic of effervescence | removes microbes and debris from wound |
effective in treating periodontal disease | hydrogen peroxide |
humans should not be exposed to akylating agents because they disrupt ___ and ___ | proteins and nucleic acids |
4 alkylating agents | formaldehyde, formalin, 2% alkaline gluteraldehyde, ethylene oxide |
agent effective against bacteria, fungi, and viruses but very toxic | formaldehyde |
35% formaldehyde, still toxic | Formalin |
alklyating agent used on heat sensitive equipment like fiber optics | 2% alkaline gluteraldehyde |
agent that disinfects instruments in 10min | 2% alkaline gluteraldehyde |
agent acts as a cold sterilant by killing spores in 3 to 12 hr | 2% alkaline gluteraldehyde |
akylating agent used in gaseous form | Ethylene Oxide |
Ethylene oxide is ___ and highly toxic to ___ | explosive, skin/mucus membranes |
Used for heat sensitive items, autoclave, and packaged sterile items. muse be well ventilated to eliminate it from the packages | Ethylene Oxide |
Dye used to inhibit growth of microbes | Gentian violent |
3 dye uses | impetigo (from Staph/Strep) which is now treated by antiotics, Trichomonas, and Candida albicans |
Type of agent used for neonatal umbilical cord | Dye |
4 physical methods of control | heat refrigeration radiation filtration |
Boiling is a ___ procedure which will generally kill in ___. | disinfecting, 10min |
boiling will kill ___ and ___ but not ___ | vegetative cells, fungal spores, bacterial endospores |
lowest temp at which organism is killed in 10min | TDP |
time it takes to kill at given temp | TDT |
Time required to kill 90% of microbes at specific temp, used in food industry | decimal reduction time (D value) |
autoclaving is... | steaming under pressure, like pressure cooking, allows temp to go higher than 100C |
can't be used for items adversely affected by steam | autoclaving |
microbe used to test autoclave | Bacillus stearothermophilus |
used for beverages, NOT a ___ technique. | pasteurization, sterilization |
used for substances immiscible in or sensitive to water | dry heat oven |
physical method only retards growth | refrigeration |
refrigeration is an ineffective method for ___ and ___ strains | psychrophilic and psychroduric |
stops growth by reducing number of possible chem rxns | freezings |
___ should be stored in fridge, not freezer, because too sensitive for ice damage | bacteriophages |
drying can have limited effective because... | some foods can retain enough water to support growth |
drying of the specimen from the frozen state | freeze drying (lyophilization) |
best long term storage for bacterial cultures | freeze drying |
3 types of radiation | UV, Xray, microwaves |
non-ionizing radiation causes formation of thimine dimers | UV |
radiation used in ceiling lights and biological safety cabintes | UV |
radiation used for air and surface disinfection | UV |
radation type that must be controlled because it is hazardous to skin and eyes | UV |
radiation that does not penetrate glass, plastic, or dirt films | UV |
radiation used to treat sewage because microbes can be killed without adding chemicals | UV |
ionizing radiation | X rays |
radiation type that causes breaks in DNA sugar phosphate causing translocations | X-Rays |
radiation used to lengthen food shelf life | X-Rays |
X-Ray leaves residiual radiation on foods, true or false | false |
radiation that kills by vibrating water | microwave |
___ lack water and are not killed by ___ | endospores, microwave |
used to physically remove microbes from liquid | 0.4um membrane filters |
HEPA aka | high-efficiency particulate air |
filttration used in ventilation systems and biological safety cabinets | HEPA |
HEPA pore size | 0.3um |
filtration used in ORs, burn units, or tuberculosis rooms | HEPA |
laminar flow hoods protect lab from aerosols using this filter | HEPA |
association between two species | symbiosis |
3 types of symbiotic relationships | mutualism, commensalisms, parasitism |
define and give example of mutalism | both members benefit, E.coli in intestines produce vitamins, Trichonympha in gut of termite |
define parasitism | parasite benefited, host harmed |
define and give example of commensalism | one benefits, the other is unharmed. staph on skin or non-pathogenic strains in intestines |
definition of infection | multiplication of any parasitic organism within or upon host |
definition of infestation | used to refer to larger parasites, worms, or arthropods |
define disease | body's reaction to an infection. interferes with body's normal function |
define pathogenicity | capability to produce disease |
define virulence | refers to the intensity of the disease produced by pathogens |
can increase by animal passage | virulence |
define attenuation | virulence of a pathogen can be decreased by repeated subculturing on lab media |
what are resident flora | microbes that are always at a particular site |
what are transient flora | flora that are temporarily present |
what are sterile body fluids (5) | blood, CSF, pre-secretion saliva, urine in kidney and bladder, semen prior to entry into urethra |
9 locations of resident microflora | conjunctiva, nose, mouth, pharynx, skin, colon, rectum, urethra, vagine |
3 conditions for opportunistic microbes | failure of hosts defenses intro of organisms into unusual body sites disturbed microbiota |
3 virulence factors | adhesins, colonization, invasiveness |
What are Adhesins | proteins/glycoproteins on surface or pili or capsules attach to host surface |
what is colonization | pathogens must survive and reproduce despite host defenses |
what is invasiveness | ability to invade host tissues. bubonic plague by flea bite is 55% fatal. pneumonic plague by aerosols is 98% fatal |
exotoxin description | protein, heat labile, specific tissue toxicity (neurotoxin, enterotoxin) |
hyaluronidase activity | invasive pathogens reach surface, produce hyaluronidase, pathogens invade deeper |
description of coagulase activity | walls off Staph to protect it from body defenses, causes plasma to clot |
description of strpetokinase activity | dissolves blood clots from by coagulase |
endotoxin activity | LPS of G- wall, heat stable, non-specific activity, can cause system shock and death |
leukocidin | released by bacteria once engulged by phagocytes, kills phagocytes |
luekostatin | released by bacteria to inhibit phagocytosis |
4 types of infectious disease | acute, chronic, sub-acute, latent |
what is an acute disease, give example | develops and runs course rapidly, influenza |
what is a chronic disease, give example | develops slowly and persists, TB and leprosy |
what is a sub-acute disease, give example | intermediate, gingivitis |
what is a latent disease | periods of inactivity, herpes simplex virus |
septicemia | pathogen multiplying in blood |
bacteremia | pathogen present not multiplying |
viremia | virus not multiplying |
toxemia | toxins in blood |
primary infection | initial infection, usually acute |
secondary infection | follows primary infection due to weakened condition |
superinfection | secondary infection that results from destrution of normal flora |
2 examples of superinfections | Candida, C. difficile |
define and give example of mixed infections | caused by multiple organisms, periodontal disease |
define and give example of subclinical infection | patient fails to show signs of the infection due to low number of pathogens or effective immune response, hep B |
define "sign" | characteristics that can be observed like swelling, redness, pus |
define "symptoms" | characteristics that patient feels like pain and nausea |
define syndrome | combinations of signs and symptoms that are indicative of a particular disease |
define sequelae | aftereffects of a particular disease, after recovery |
acme and flminating | point of worst signs and symptoms seen. fulminating if sudden and severe |
Define epidemiology | study of factors and mechanisms involved with the frequency and spread of disease within populations |
define etiology | causative agent of disease in a population |
define incidence rate | number of new cases within a period |
define prevalence rate | total number of people infected within the population |
morbidity rate | number of indiv. affected in set period |
mortality rate | number of deaths due to disease |
endemic | continually present, like chicken pox |
epidemic | higher than normal incidence rate, diphtheria in soviet union |
pandemic | worldwide spread, cholera |
sporadic | random unpredictable manner of occurrence, EEE |
3 disease Reservoirs | human, living, non-living |
3 points about human carriers | healthy- subclinical or incubation chronic- typhoid Mary intermittent- periodically release |
bubonic plague inhabits rat fleas, example of what type of carrier | animal |
2 sources of non-living disease carriers | soil- reservoice for fungal spores and helminths improperly cooked or stored food |
3 types of disease transmission | contact, vehicles, vectors |
3 types of contact transmission | direct, indirect, droplet |
direct transmission occrus by | body contact |
horizontal transmission | any type of touching |
vertical direct transmission | offspring via placenta, gametes,vaginal canal, or milk |
auto-inoculation direct transmission | touching lesion than touching eye |
fecal-oral direct transmission | unwashed hands |
indirect contact transmission | contaminated fomites like utensils, toys, tissues |
droplet direct transmission | aerosols created by sneezing or coughing that are inhaled |
3 types of vehicle transmission | waterborne, airborne, foodborne |
waterborne vehicle transmission | feces contaiminate water source |
airborne vehicle transmission | travel more than 1mi. in air, Coccidioides |
foodborne vehicle transmission | improper processing/cooking |
vector transmission | mechanical and biological-- most are arthropods |
4 controls of disease transmission | isolation, quarantine, immunization, vector control |
nosocomial infections | acquired in hospital |
% of patients that acquire nosocomial infections | 10% |
exogenous nosocomial infection | enter patient from people or fomites |
endogenous nosocomial infection | opportunistics |
compromised host nosocomial infection | indiv. susceptible to disease due to some pre-existing factor |