unit 9 (antimicrobial methods and eukaryotic microorganisms) Flashcards
two factors that influence the level of cleanliness required for a particular fomite
application for which the item will be used, level of resistance to antimicrobial treatment by potential pathogens
sterilization definition
the complete removal or killing of all vegetative cells, endospores, and viruses from the targeted item or environment
sterilization can be accomplished through
physical means: high heat, pressure, or filtration and chemical means
sterilants definition
chemicals that can be used to achieve sterilization
aseptic technique definition
involves a combination of protocols that collectively remain sterility, or asepsis, thus preventing contamination of the patient with microbes and infectious agents
antisepsis definition
reduces microbial load on skin or tissue through application of antimicrobial chemical
sepsis definition
a systemic inflammatory response to an infection that results in high fever, increased respiratory and heart rates, shock, and possibly death
sterile field definition
a designated area that is kept free of all vegetative microbes, endospores, and viruses
disinfection definition
reduces or destroys microbial load of an inanimate object through application of heat or antimicrobial chemicals
ideal characteristics for disinfectants/antimicrobials
fast acting, stable, easy to prepare, inexpensive, and easy to use
disinfection is not sterilization because
some microbes remain, endospores tend to survive even when all vegetative cells have been killed
what are antiseptics
chemicals safe for use on living skin or tissues
critical items definition
must be sterile because they will be used inside the body, often penetrating sterile tissues or the bloodstream
semi-critical items definition
items that do not need to be sterilized but require a high level of disinfection because they come in contact with mucous membranes or nonintact skin but do not penetrate tissues
noncritical items definition
items that need to be cleaned but not highly disinfected because they come in contact with, but to not penetrate, intact skin
degerming definition
microbial numbers are greatly reduced by gently scrubbing living tissue with a mild chemical
sanitization definition
cleansing of fomites to remove enough microbes to achieve levels deemed safe for public health.
-cide or -cidal refers to
physical and chemical methods of microbial control that kill the targeted microorganism
-stat or -static refers to
physical or chemical methods that do not kill the organism, but stop their growth
factors that determine whether a particular treatment is -static or -cidal
types of microorganisms targeted, the concentration of chemicals used, and the nature of the treatment applied
microbial death curve
how degree of microbial control is evaluated, describes the progress and effectiveness of a particular protocol
decimal reduction time (DRT) definition
the amount of time it takes for a specific protocol to produce a one-order-of-magnitude decrease in the number of organisms, or death to 90% of the population
factors that contribute to the effectiveness of an antimicrobial protocol
length of exposure, amount of microbes, susceptibility of microbe to antimicrobial, concentration of antimicrobial, temperature, conditions that limit the contact between the agent and the microbe
physical methods of control examples
heat, cold, pressure, desiccation, radiation, sonication, filtration
thermal death point (TDP) definition
the lowest temperature at which all microbes are killed in a 10 minutes exposure
thermal death time (TDT) definition
length of time needed to kill all microorganisms in a sample at a given temperature
boiling kills
kills vegetative cells and some viruses
boiling mode of action
moist-heat control that denatures proteins and alters membranes
categories of heating protocols
dry-heat sterilization and moist-heat sterilization
dry-heat sterilization examples
aseptic technique of inoculating loops, incineration
moist-heat sterilization example
autoclave
most effective heat sterilization category is __ because
moist-heat sterilization because it can penetrate cells better than dry heat does
autoclaves function by
raising temperatures above the boiling point of water (steam) and pressure to sterilize items
autoclaves kill
vegetative cells, viruses, and endospores (everything except for prions basically)
autoclave mode of action
moist-heat control that kills cells by denaturing proteins and alters membranes
autoclave tape function
indicates when appropriate temp is reached: white strips turn black when appropriate temp is achieved
biological indicator spore test function
uses strip of paper of endospores to determine whether endospores were killed or not during the autoclave process
Diack tube function
indicates when proper sterilization temperature is reached in an autoclave; a temperature sensitive pellet melts at proper sterilization temp
traditional pasteurization kills
pathogens and reduces the number of spoilage causing microbes
pasteurization mode of action
denatures proteins and alters membranes
high-temp short-time (HTST) pasteurization
exposes milk to 72 degrees for 15 secs, which lowers bacteria numbers while preserving quality
ultra-high-temp (UHT) pasteurization
milk is exposed to 138 degrees for 2 seconds, causing slight change to taste and smells
refrigeration mode of action
inhibits metabolism, slows or arrests cell division
freezing mode of action
stops metabolism, may kill microbes
high-pressure processing kills
vegetative bacteria (not endospores), yeast, molds, parasites, and viruses (not endospores)
high-pressure processing mode of action
denatures proteins and can cause cell lysis
hyperbaric oxygen treatment mode of action
inhibits metabolism and growth of anaerobic microbes
desiccation kills
can kill all types of cells because all cells require water, except endospores
simple desiccation (drying) mode of action
inhibits metabolism
reduce water activity (addition of solute) mode of action
inhibits metabolism and can cause cell lysis
lyophilization (freeze-drying) mode of action
inhibits metabolism
ionizing radiation types
x-rays, gamma rays, and high-energy electron beams
ionizing radiation mode of action
sterilizes by altering molecular structures, introduces double strand breaks into DNA
ionizing radiation is used on
packaged items that cannot be autoclaved (plastic)
what is nonionizing radiation
ultraviolet light that sterilizes but does not penetrate cells or packaging
nonionizing radiation mode of action
introduces thymine dimers, leading to mutation that eventually kill the cell
sonication definition
use of high frequency sound waves to disrupt cell structures
sonication mode of action
cavitation disrupts cells, lysing them
cavitation definition
formation of bubbles inside the cell
filtration mode of action
physically removes microbes from air or liquid
high efficiency particulate air (HEPA) filters trap
bacterial cells, endospores, viruses, nearly sterilizing the air
membrane filters remove __ from ___
microbes from liquid samples
factors to consider when choosing chemical antimicrobials
type of microbe targeted, how clean the item needs to be, the disinfectant’s effect on item integrity, its safety, its expense, and its ease of use
chemical antimicrobial examples
phenolics, heavy metals, halogens, alcohols, surfactants, bisbiguanides, alkylating agents, peroxygens, supercritical fluids, and chemical food preservatives
phenol mode of action
inhibit microbial growth by denaturing proteins and disrupting membranes
phenols are used in
mouthwash and toothpaste, lysol, agriculture, impregnated into products
phenolics characteristics
tend to be stable and persistent on surfaces
heavy metals mode of action
kill microbes by binding to proteins, thus inhibiting enzymatic activity
oligodynamic definition
very small concentrations show significant antimicrobial activity
heavy metals examples
mercury, silver, copper, nickel, zinc
mercury mode of action
bacteriostatic; bind to sulfur-containing amino acids within proteins, inhibiting their functions
silver is used as __ in __
antiseptic in antibiotic creams, making them thousands of times more effective
copper sulfate is a common
algicide used to control algal growth in pools and fish tanks
halogen examples
iodine, chlorine, and fluorine
iodine mode of action
disinfects by oxidizing cellular components
chlorine mode of action
disinfects by producing a strong oxidant that is uncharged and enters cells easily
chloramine characteristics
disinfect, stable, release chlorine over long periods of time
fluorine mode of action
accumulates in plaque-forming bacteria, interfering with their metabolism
alcohol mode of action
disinfect and antiseptic by rapidly denaturing proteins, inhibiting cell metabolism, disrupting membranes, leading to cell lysis
alcohols effective against
bacteria, fungi, enveloped viruses
surfactant definition
group of chemical compounds that lower the surface tension of water
surfactant mode of action
degerm by physically lifting away dirt and microbes from surfaces and skin
quaternary ammonium salts (quats) mode of action
insert into the bacterial phospholipid bilayer and disrupt membrane integrity
characteristic of quats
stable, nontoxic, inexpensive, colorless, odorless, and tasteless
quats kill
fungi, protozoans, bacteria, enveloped viruses (not endospores or nonenveloped)
bisbiguanide (chlorhexidine) mode of action
disrupts cell membranes and causes cell’s cytoplasmic contents to congeal and is bacteriostatic at lower concentration, bactericidal at higher
bisbiguanide (chlorhexidine) kills
yeasts, gram+ and - bacteria, enveloped viruses
alkylating agents mode of action
replace a hydrogen atom within a molecule with an alkyl group, thereby inactivating enzymes and nucleic acids
alkylating agents examples
formaldehyde, glutaraldehyde, o-phthalaldehyde (OPA), ethylene oxide, beta-propionolactone
formaldehyde kills
bacteria, viruses, fungi, and endospores
formaldehyde leads to
sterilization at low temperatures
ethylene oxide
highly penetrating, gaseous sterilizer
peroxygen examples
hydrogen peroxide, peracetic acid, benzoyl peroxide, carbamide peroxide, ozone gas
hydrogen peroxide mode of action
produces free radicals that damage cellular macromolecules
hydrogen peroxide kills
gram- and + bacteria (more effective against gram+), fungi, viruses, endospores, decreased efficacy against bacteria that produce catalase and peroxidase
peracetic acid characteristics
can be used as a liquid or plasma sterilant, readily kills endospores, more effective than hydrogen peroxide, immune to inactivation by catalase and peroxidase, and breaks down into environmentally innocuous compounds
ozone gas characteristics
disinfectant used to clean air or water supplies
supercritical fluid definition
carbon dioxide that is brought to 10 times atmospheric pressure and gains physical properties between those of liquids and gases
supercritical carbon dioxide mode of action
penetrates cells and forms carbonic acid, which lowers cell pH considerably
supercritical carbon dioxide kills
vegetative cells, can kill endospores when combined with peracetic acid
characteristics of supercritical carbon dioxide
nonreactive, nontoxic, nonflammable, effective at low temps, preserves object’s integrity
chemical food preservative examples
sorbic acid, benzoic acid, propionic acid and their soluble salts potassium sorbate, sodium benzoate, calcium propionate; sulfur dioxide, nitrites
sorbic acid mode of action
inhibits various cellular enzymes (those in Krebs cycle, catalase, peroxidase)
benzoic acid mode of action
decreases intracellular pH, interfering w/ mechanisms such as oxidative phosphorylation and the uptake of molecules such as amino acids into cells
propionic acid mode of action
inhibits enzymes and decreases intracellular pH, working similarly to benzoic acid
sulfur dioxide (sulfites) mode of action
may interfere w/ the disulfide bond formation in proteins, inhibiting enzymatic activity. they may reduce cell pH, interfering w/ proton motive force
nitrite mode of action
reacts w/ enzyme ferredoxin in bacteria, this electron transport chain carrier is destroyed, preventing ATP synthesis
natural chemical food preservative examples
nisin, natamycin
nisin mode of action
disrupts cell wall production, leaving cells prone to lysis
high level germicide definition
have the ability to kill vegetative cells, fungi, viruses, and endospores, leading to sterilization
intermediate-level germicides
less effective against endospores and certain viruses
low-level germicides
kill only vegetative cells and certain enveloped viruses, ineffective against endospores
disk-diffusion method for testing antimicrobial effectiveness
chemicals are applied to separate, sterile, filter paper disks. the disks are then placed on a plate w/ the target bacterium and the chemicals form a zone of inhibition based on their effectiveness against the target bacterium
use-dilution test
cylinder of stainless steel is dipped into culture of target microorganism, cylinder is dipped in solutions of disinfectant at various concentrations for specific amount of time, cylinder is transferred to a medium to see if bacteria grow
in-use test determines
whether disinfectant solutions are being used correctly in clinical settings
protist definition
informally refers to a diverse group of microscopic eukaryotic organisms: “animal-like” protozoans, “plant-like” algae, and “fungus-like” protists such as water molds
algae basic characteristics
photosynthetic organisms that can be unicellular or multicellular
protozoa basic characteristics
non-photosynthetic, heterotrophic, motile organisms that are always unicellular
plankton definition
microorganisms that drift or float in water, moved by currents
types of plankton
zooplankton, which are motile and non-photosynthetic, and phytoplankton, which are photosynthetic
trophozoites
protozoans that are beneficial symbionts that feed on small particulate food sources like bacteria
cyst definition
a cell with a protective wall
encystment definition
the process by which a trophozoite becomes a cyst when environmental conditions are too harsh
excystment definition
process by which cysts are triggered by environmental cues to become active again
protozoans reproduce sexually, asexually, or both
reproduce both sexually and asexually
modes of asexual reproduction in protozoans
binary fission, budding, or schizogony
schizogony process
nucleus of the cell divides multiple times before the cell divides into many smaller cells
merozoites definition
the products of schizogony
schizonts definition
structures that merozoites are stored in
modes of sexual reproduction in protozoans
syngamy, conjugation
syngamy definition
production of haploid gametes that fuse
conjugation (protozoan sexual reproduction)
exchange genetic material by joining to exchange DNA (different than bacterial conjugation)
protist conjugation definition
refers to a true form of eukaryotic sexual reproduction between two cells of different mating types
all protozoans have a
plasma membrane, or plasmalemma
pellicle formed from
bands of proteins just inside the plasma membrane that add rigidity that some protozoans have
ectoplasm definition
outer gel layer of the cytoplasm under the plasma membrane that some protists have
endoplasm definition
inner layer and sol (fluid) region of the cytoplasm that some protists have
cytosome definition
specialized structure for taking food in through phagocytosis that some protozoans have
cytoproct definition
specialized structure for the exocytosis of wastes that some protozoans have
holozoic definition
protozoans that ingest whole food particles through phagocytosis
saprozoic definition
protozoans that ingest small, soluble food molecules
protozoan motile structures
flagella or cilia made of microtubules, pseudopodia
contractile vacuoles definition
organelles that can be used to move water out of the cell for osmotic regulation that are found in some protozoans
mitochondria in parasites
may be absent or altered to kinetoplastids or hydrogenosomes
polyphyletic group definition
group that lacks a shared evolutionary history
domain Eukarya six supergroups
Excavata, Chromalveolata, Rhizaria, Archaeplastida, Amoebozoa, Opisthokonta
Amoebozoa includes
protozoans that used amoeboid movement
amoeboid movement
actin microfilaments produce pseudopodia, into which the remainder of the protoplasm flows, thereby moving the organism
Amoebozoa subgroup examples
slime molds, Entamoebas
slime mold types
cellular slime mold and plasmodial slime molds
cellular slime mold exist as
exist as individual amoeboid cells that periodically aggregate into a mobile slug, which then forms a fruiting body that produces haploid spores
plasmodial slime mold exist as
large, multinucleate amoeboid cells that form reproductive stalks to produce spores that divide into gametes
Chromalveolata is united by
similar origins of its members’ plastids and includes the apicomplexans, ciliates, oomycetes, diatoms, and dinoflagellates
apicomplexans
intra- or extracellular parasites that have an apical complex at one end of the cell
apical complex
concentration of organelles, vacuoles, and microtubules that allows the parasite to enter host cells
apicomplexan life cycle
complex life cycles that include an infective sporozoite that undergoes schizogony to make many merozoites
examples of apicomplexan
the genus Plasmodium, Toxoplasmosis gondii, Cryptosporidium parvum
ciliates (Chromalveolata) characterized by
the presence of cilia on their cell surface
ciliate nucleus comes in the form of
a micronucleus and macronucleus
micronucleus
diploid, somatic, and used for sexual reproduction by conjugation
macronucleus
derived from the micronucleus, becomes polyploid, and has a reduced set of metabolic genes
polyploid definition
multiple sets of duplicate chromosomes
reproduction by conjugation produces
two cells that are genetically different from each other and from their previous versions
oomycetes are called
water molds
oomycetes characteristics
cell walls of cellulose, generally diploid
Excavata members characterized by
depression on the surface of the cell called an excavate
Excavata subgroups
Forincata, Parabasalia, Euglenozoa
Forincata characteristics
lack mitochondria but have flagella
Parabasalia characteristics
frequent animal endosymbionts, basal bodies, modified mitochondria (kinetoplastids), large complex cell structure w/ an undulating membrane, often have many flagella
Euglenozoa characteristics
cells have two flagella, a pellicle, a stigma to sense light, and chloroplasts for photosynthesis
major groups of parasitic helminths
roundworms (Nematoda) and flatworms (Platyhelminthes)
monoecious definition
having both male and female reproductive organs in a single individual
dioecious definition
having either male or female reproductive organs
Phylum Nematoda worms are
unsegemented worms that have a full digestive system even when parasitic
Nematoda are parasites of what area of the body
common intestinal parasites, their eggs can sometimes be identified in feces or around the anus of an infected individual
Nematoda parasite examples
Ascaris lumbricoides, Enterobius vermicularis (pinworm), Toxocaria canis and T. cati (toxocariasis), Necator americanus (hookworm), Trichinella spiralis (trichinosis), Dirofilaria immitis (heartworm)
Phylum Platyhelminthes includes
flukes, tapeworms, and turbellarians
flukes (trematodes) are characterized by
nonsegmented flatworms that have an oral sucker and attach to inner walls of intestines, lungs, large blood vessels , or the liver
important examples of flukes
liver flukes, intestinal flukes, oriental lung fluke, and schistosomiasis
tapeworms (cestodes) characterized by
segmented flatworms that may have hooks or suckers at the scolex (head region)
proglottids
what body of tapeworm is made up of, contains reproductive structures that detach when the gametes are fertilized, releasing gravid proglottids w/ eggs
tapeworm intermediate host function
consumes the eggs, which then form into larval form called oncosphere that travels to a particular tissue or organ to form a cysticerci
after cysticerci are consumed by definitive host
they develop into adult tapeworms in the host’s digestive system
tapeworm examples
Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm), Diphylobothrium latum (fish tapeworm), Echinococcus granulosus (dog tapeworm)
fungi characteristics
heterotrophic, saprozoic, unicellular and multicellular
mycoses definition
illnesses caused by fungi
hyphae
filaments that make up most multicellular fungal bodies
Hyphae can form
tangled network called a mycelium and form the thallus (body) of fleshy fungi
septate hyphae
hyphae that have walls between the cells
nonseptate (coenocytic) hyphae
hyphae that lack walls and cell membranes between the cells
unicellular fungi are
yeasts
budding yeasts
reproduce asexually by budding off a smaller daughter cell
pseudohyphae
budding yeast cells that sometimes stick together as a short chain
example of a common yeast that forms a pseudohyphase
Candida albicans
dimorphic fungi definition
having more than one appearance during their life cycle, appearing as yeasts or molds
example of a dimorphic fungi
Histoplasma capsulatum, the pathogen that causes histoplasmosis
fungal cell wall have
chitin and ergosterol
fungi reproduce sexually through either
cross-fertilization or self-ferilization
plasmogamy (fungi sexual reproduction)
cytoplasms of the + and - type gametes fuse, producing a cell w/ two distinct nuclei
karyogamy (fungi sexual reproduction)
the two nuclei fuse to create a diploid zygote, which undergoes meiosis to form spores that germinate to start the haploid stage, which eventually creates more haploid mycelia
sexually produces spores are known as
zygospores (in Zygomycota), ascospores (in Ascomycota), or basidiospores (in Basidiomycota)
fungi can reproduce asexually by
mitosis, mitosis w/ budding, fragmentation of the hyphae, and formation of asexual spores by mitosis
seven major groups of Fungi
Urediniomycetes and Ustilagomycetes, Glomeromycota, Chytridiomycetes, Zygomycota, Ascomycota, Basidiomycota, Microsporidia
Urediniomycetes and Ustilagomycetes include
plant rusts and smuts, respectively
Glomeromycota includes
mycorrhizal fungi, obligate symbionts associated w/ plant roots: fungi receives carbs from plant roots, plant benefits by increased ability to take up nutrients and minerals from the soil
Chytridiomycetes characteristics
small fungi that are generally aquatic and have flagellated, motile gametes
Zygomycota characteristics
mainly saprophytes with coenocytic hyphae and haploid nuclei; they use sporangiospores for asexual reproduction
zygospores
what Zygomycota uses for sexual reproduction, have hard walls formed from the fusion of reproductive cells from two individuals
Ascomycota characteristics
septate hyphae, cup-shaped fruiting bodies called ascocarps, use sexually produced ascospores, use asexual spores called conidia
medically important ascomycota
Trichophyton, Microsporum, Epidermophyton, Blastomyces dermatitidis, Histoplasma capsulatum, Candida albicans
unicellular Ascomycota examples
Saccharomyces
Basidiomycota characteristics
have basidia (club-shape structures) that produce basidiospores within fruiting bodies called basidiocarps
Basidiomycota disease example
Cryptococcus neoformans can cause serious lung infections when inhaled by individuals w/ weakened immune systems
Microsporidia characteristics
unicellular fungi that are obligate intracellular parasites; lack mitochondria, peroxisomes, and centrioles; spores release a unique polar tubule that pierces host cell membrane to allow the fungus to enter
microsporidiosis definition
human infections w/ microsporidia pathogen
algae are
autotrophic protists that can be unicellular or multicellular
algae are found in supergroups
Chromalveolata (dinoflagellates, diatoms, golden algae, and brown algae) and Archaeplastida (red and green algae)
harmful algal bloom occur when
algae grow too quickly and produce dense populations, can produce high concentrations of toxin
pyrenoids
structures inside of algal chloroplasts that synthesize and store starch
primary chloroplasts membranes
have two membranes, one from original cyanobacteria that the ancestral eukaryotic cell engulfed, and one from the plasma membrane of the engulfing cell
seaweeds differ from plants because
they do not have true tissues or organs like plants do, they do not have a waxy cuticle to prevent desiccation
algal reproduction
may be asexual by mitosis or sexual using gametes
algae that fall in Chromalveolata
dinoflagellates and stramenopiles
dinoflagellates nutritional types
may be phototrophic, heterotrophic, or mixotrophic
photosynthetic dinoflagellates use what chlorophylls
chlorophyll a, chlorophyll c2, and other photosynthetic pigments
dinoflagellates have how many flagella
two flagella that cause them to whirl
theca on dinoflagellates
cellulose plates that form a hard outer covering as armor
dinoflagellates neurotoxin causes
paralysis in humans and fish
red tide
a harmful algal bloom created by a dense population of dinoflagellates
stramenopiles include
golden algae, brown algae, and the diatoms
stramenopiles photosynthetic pigments
chlorophyll a, chlorophyll c1/2, and fucoxanthin
stramenopile storage carbohydrate
chrysolaminarin
diatom characteristics
have flagella and frustules, which are outer cell walls of crystallized silica; their fossilized remains are used to produce diatomaceous earth; can reproduce sexually or asexually
brown algae characterisitics
multicellular marine weeds; have leaf-like blades, stalks, and structures called holdfasts that are used to attach to substrate
brown algae photosynthetic pigments
chlorophyll a, chlorophyll b, beta-carotene, and fucoxanthine
brown algae storage carbohydrate
laminarin
Archaeplastids include
green algae (Chlorophyta), red algae, another group of green algae, and the land plants (Charophyta)
Charaphyta are most similar to land plants because
they share a mechanism of cell division and an important biochemical pathway, among other traits
like land plants, Charaphyta and Chlorophyta have
chlorophyll a and b as photosynthetic pigments, cellulose cell walls, and starch as a carbohydrate storage
Chlamydomonas is a green alga that has
a single large chloroplast, two flagella, and a stigma
red alga characteristics
mainly multicellular but have some unicellular forms, rigid cell walls containing agar or carrageenan
