Term
|
Definition
(most common) source of illumination is visible light, used to visualize bacteria due to contrast difference in bacteria and medium |
|
|
Term
|
Definition
[image]
reflected light is used to visualize bacteria too thin to be seen by bright field (e.g. Treponema pallidum) (diagnoses syphillis well) |
|
|
Term
|
Definition
[image]stains cells, not extracellular medium |
|
|
Term
|
Definition
[image]
stains extracellular medium, not cells (e.g. india ink stain for visualizing capsules) |
|
|
Term
|
Definition
[image]
Procedure = (1) crystal violet - primary stain (purple); (2) iodine - mordant (fixative); (3) alcohol - decolorizer; (4) Saffarnin - counterstain (red) |
|
|
Term
Why does differential staining occur? |
|
Definition
[image]
Gram-positive cell wall (extensive peptidoglycan layer) retains crystal violet-iodine complex; Gram-negative wall does not |
|
|
Term
|
Definition
|
|
Term
|
Definition
[image]
clusters (arrangement) |
|
|
Term
|
Definition
[image]
chain (arrangement) |
|
|
Term
|
Definition
|
|
Term
|
Definition
[image]
rod (shape)
Bacillus are Gram(+)positive
Two Bacillus species are considered medically significant: B. anthracis, which causes anthrax, and B. cereus, which causes a foodborne illness similar to that of Staphylococcus.A third species, B. thuringiensis, is an important insect pathogen, and is sometimes used to control insect pests. The type speciesis B. subtilis, an important model organism. It is also a notable food spoiler, causing ropiness in bread and related food. |
|
|
Term
|
Definition
[image]
curved rod (shape) e.g. Vibrio |
|
|
Term
|
Definition
[image]
spirochetal (shape) e.g. Treponema |
|
|
Term
|
Definition
varies in size and shape e.g. Haemophilus influenzae |
|
|
Term
|
Definition
[image]
a bacterial flagellar antigen; important in serological identification of bacteria |
|
|
Term
|
Definition
[image]
a bacterial capsular antigen, external to the cell wall; important for serological identification |
|
|
Term
|
Definition
[image]
an aggregate of microorganisms in which cells adhere to each other in a self-producing matrix; a protected structure of bacterial cells/microcolonies enmeshed in mucoid (hydrated) exopolysaccharide adhering to a wet surface (inert or living) ... biofilms may form on living or non-living surfaces, and may be prevalent in industrial/hospital settings |
|
|
Term
fluid mosaic model of the cell membrane |
|
Definition
polypeptides are embedded in the phospholipid bilayer with hydrophilic regions extended out into the cytoplasm, the extracellular volume or both |
|
|
Term
|
Definition
phospholipid bilayer with hydrophilic groups at top and bottom and hydrophobic groups in middle |
|
|
Term
|
Definition
[image]
bacteria with cell walls consisting of thick layers of peptidoglycan will retain the violet inkstain of the Gram stain procedure |
|
|
Term
|
Definition
[image]
bacteria with thinner cell walls with less peptidoglycan will lose the violet inkstain during the decolorization stage of Gram staining procedure |
|
|
Term
Do both Gram-positive and Gram-negative bacteria possess peptidoglycan? |
|
Definition
|
|
Term
|
Definition
[image]
fabric shell encasing the cell; network of polymers, containing N-acetylmuramic acid and N-acetylglucosamine; N-acetylmuramic acid subunits on different strands are cross-linked via their peptide stems (aka amino acid sidechains), which provides mechanical strength and prevents the cell from bursting via osmotic pressure |
|
|
Term
|
Definition
[image]
lipopolysaccharide (aka endotoxin) |
|
|
Term
|
Definition
[image]
antigen occurring in the lipopolysaccharide layer of the wall of Gram-negative bacteria |
|
|
Term
|
Definition
[image]
the peptidoglycan layer … major function is osmotic protection; also function in nutrient uptake, sensory (chemotaxis) mechanism, degradative enzymes |
|
|
Term
|
Definition
lipid bilayer … major function is exclusion of some dyes; differentially permeable … Gram-positive bacteria lack an outer membrane |
|
|
Term
|
Definition
[image]
composed of disaccharides, phosphate groups, and fatty acids … the toxicity of LPS lipopolysaccharide is primarily associated with Lipid A |
|
|
Term
|
Definition
[image]
part of LPS lipopolysaccharide; may contain sugars, aminosugar, sugar acids, sugar alcohols; often contains the uniqe sugar ketodeoxyoctulonate (KDO) |
|
|
Term
|
Definition
[image]
ketodeoxyoctulonate; unique sugar found in core polysaccharide of LPS |
|
|
Term
|
Definition
[image]
consists of a unit (sugars, aminosugars, sugar acids, sugar alcohols) repeated N-number of times … highly specific region, e.g. Salmonella |
|
|
Term
lipooligiosaccharide (LOS) |
|
Definition
[image]
certain bacteria lack O-antigenic (LPS) chain, only contain Lipid A and extended core - e.g. Neisseria meningitidis, N. gonorrhoeae, Haemophilus influenzae, Haemophilus ducreyi
LOS is a potent endotoxin that can cause petichae, purpura, septic shock |
|
|
Term
|
Definition
fever-producing entity (e.g. LPS) |
|
|
Term
|
Definition
|
|
Term
|
Definition
[image]
systemic inflammatory response syndrome … similar to acute inflammation (acute phase response), but on a systemic scale with macrophages, PMNs, endothelial cells serving as effector cells |
|
|
Term
|
Definition
distributive shock (hypovolemic shock) |
|
|
Term
|
Definition
[image]
disseminated intravascular coagulation; pathological activation of blood clotting |
|
|
Term
|
Definition
|
|
Term
|
Definition
[image]
the presence of both (a) proven infection - e.g. pneumonia, UTI, bacteremia, as well as (b) SIRS |
|
|
Term
|
Definition
[image]
the presence of both (a) sepsis [= infection + SIRS] as well as (b) organ failure |
|
|
Term
|
Definition
[image]
the bresence of both (a) severe sepsis, as well as (b) refractory hypotension |
|
|
Term
|
Definition
[image]
caused by loss of fluid from the vascular system; blood pressure drops … not vascular obstructive, not cardiogenic |
|
|
Term
leukopenia (or leukocytosis) |
|
Definition
abnormally low (or high) levels of peripheral white blood cells in the blood |
|
|
Term
|
Definition
activated human recombinant protein C; inhibits clotting, inhibits inflammation, activates fibrinolysis … used as treatment to control SIRS/DS |
|
|
Term
|
Definition
also known as autoprothrombin IIA and blood coagulation factor XIV ... protein C inhibits clotting (anticoagulant), activates fibrinolysis, inhibits inflammation ... does this by inactivating Factor Va and Factor VIIIa
[image]
pt's with deficiency or resistance to protein C will be at a significantly increased risk of forming dangerous blood clots (thrombosis) |
|
|
Term
|
Definition
[image]
additional polymer of glycerol or ribitol phosphate, found in Gram-positive cell wall stain … functions in adherence, antiphagocytic |
|
|
Term
Do the cell walls of Gram-positive bacteria contain LPS/endotoxin, or an outer membrane? |
|
Definition
|
|
Term
|
Definition
[image]
additional polymers of glycerol or ribitol phosphate, found in Gram-positive cell wall stain … function to produce endotoxin-like shock, interacts with C-reactive protein, activates alternative complement pathway |
|
|
Term
|
Definition
LPS-signal-transducer receptor protein, located on macrophages, sends the LPS signal through cytoplasm to the nucleus |
|
|
Term
|
Definition
[image]
pathogen-associated molecular patterns; include peptidoglycan, teichoic acids, CpG nucleotides, and of course LPS |
|
|
Term
What are the two genera of endospore-formers? |
|
Definition
|
|
Term
|
Definition
[image]
the complete viral particle |
|
|
Term
|
Definition
[image]
protein subunits of the capsid; repetetive polypeptide subunits arranged in symmetric patterns = capsid |
|
|
Term
|
Definition
[image]
the protein shell (or coat) that encloses the core of the NA nucleic acid genome of a virus + any associated proteins |
|
|
Term
|
Definition
[image]
protein associated with the NA nucleic acid genome; the capsid together with the NA genome plus any associated proteins |
|
|
Term
|
Definition
[image]
the viral membrane; the "skullcap" or "scalp"; viral envelope is composed of virus-specific proteins plus host-derived lipids and carbohydrates (from nuclear, ER, Golgi, or cytoplasmic membranes) that the virus "wears" on its outer membrane; useful for identification |
|
|
Term
|
Definition
[image]
spikes … viral glycoproteins that form spike-like projections on the surface of the envelope and play a role in attachment |
|
|
Term
tegument (aka Matrix protein) |
|
Definition
[image]
amorphous layer b/w nucleocapsid and envelope that mediates the interaction b/w capsid and envelope |
|
|
Term
|
Definition
naked RNA virus (mainly plant viruses) |
|
|
Term
|
Definition
[image]
infectious protein (misfolded) which causes disease in the CNS … NOT a virus |
|
|
Term
|
Definition
[image]
type of capsid symmetry found in animal viruses; capsomeres are arranged in triangles that form a symmetric figure |
|
|
Term
|
Definition
[image]
type of capsid symmetry found in animal viruses; capsomeres are arranged in a hollow core that appears helix-shaped |
|
|
Term
|
Definition
[image]
positive sense RNA resembles mRNA and thus can be immediately translated by the host cell ... the viral nucleic acid serves as mRNA, but they must encode for an RNA-dependent RNA polymerase to make the antisense RNA to produce the viral genome |
|
|
Term
|
Definition
[image]
have a reverse transcriptase (RNA dependent-DNA polymerase) which transcribes the (+)ssRNA to DNA, then the mRNA is transcribed from the viral specific DNA … this is the target for many anti-HIV drugs, e.g. AZT |
|
|
Term
negative sense (-) ssRNA and ds-RNA |
|
Definition
[image]
RNA viruses can be classified according to the sense or polarity of their RNA. Positive sense viral RNA is similar to mRNA (can be immediately translated); whiel negative-sense RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase before translation
These virions must contain functional proteins (an RNA-dependent-RNA polymerase) to make the mRNA as well as possess the gene that codes for the protein |
|
|
Term
|
Definition
is at or near the portal of entry (POE) for a virus |
|
|
Term
|
Definition
where virus has specificity for a particular host tissue |
|
|
Term
|
Definition
[image]
involves lethal or non-lethal damage/alteration to cells and their functions, as a result of infection |
|
|
Term
|
Definition
[image]
involves periods of incubation or persistence, where there is an absence of disease symptoms during infection |
|
|
Term
|
Definition
a mass of new tissue which persists and grows independently of its surrounding structures |
|
|
Term
malignant transformation (neoplasm) |
|
Definition
the conversion of a cell from restricted growth to unrestricted growth, which is characteristic of tumors |
|
|
Term
|
Definition
[image]
ability of fungus to grow as a mycelial (mold) form at room temperature and a yeast form at 37*C |
|
|
Term
|
Definition
[image]
growth occurs by elongation of hyphae to form a mycelium … sexual and asexual spores produced |
|
|
Term
|
Definition
[image]
a long, branching filamentous structure of a fungus, or also the unrelated Actinobacteria (hypha of penicillum, above) ... cells are branching cylindrical tubules +/- septa or crosswalls; collectively called mycelium |
|
|
Term
|
Definition
[image]
mass of intertwined hyphae |
|
|
Term
|
Definition
[image]
eukaryotic microorganisms classified under the kingdom fugi ... yeasts are unicellular; asexual reproduction by budding |
|
|
Term
|
Definition
|
|
Term
|
Definition
[image]
large (macro) spores (conidia), which are not enclosed in any sort of special structure, naked spores … macroconidia are infectious form for fungi that infect skin (Dermatophytes) |
|
|
Term
|
Definition
[image]
small (micro) spores (conidia), which are not enclosed in any sort of special structure, naked spores … microconidia are small enough to get to alveoli when inhaled and are the infectious form for certin fungi |
|
|
Term
|
Definition
a close association of two different organisms |
|
|
Term
|
Definition
a beneficial association for two different organisms |
|
|
Term
|
Definition
beneficial association of one organism with another (unaffected) organism |
|
|
Term
|
Definition
beneficial association of one organism, to the detriment of another organism |
|
|
Term
|
Definition
[image]
protozoa; microscopic; single cells … motile by means of cytoplasmic extensions (pseudopodia) |
|
|
Term
|
Definition
[image]
protozoa; microscopic; single cells … motile by means of flagella |
|
|
Term
|
Definition
[image]
protozoa; microscopic; single cells … motile by means of cilia |
|
|
Term
|
Definition
[image]
protozoa; microscopic; single cells … complex life cycles with asexual and sexual stages |
|
|
Term
|
Definition
[image]
the worms. Adults mostly macroscopic, eggs microscopic. Mostly monoecious w/ male and female sex organs in the same individual |
|
|
Term
|
Definition
male and female sex organs in the same individual |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
[image]
round worms, nematodes |
|
|
Term
|
Definition
chitinous exoskeletons, e.g. lice, mites, ticks, etc. |
|
|
Term
|
Definition
host which harbors adult or sexual stage of the parasite |
|
|
Term
|
Definition
host(s) in which asexual stage(s) occur |
|
|
Term
|
Definition
source of all carbon building blocks is CO2; autotrophic bacteria "fix CO2" … cellular energy is obtained from the oxidation/reduction of inorganic ions (chemoautotroph) or harvesting light energy (photoautotroph) |
|
|
Term
|
Definition
sources of energy and carbon are organic carbon sources … most pathogenic bacteria are heterotrophic |
|
|
Term
|
Definition
[image]
have complex growth requirements (specific nutrient, atmospheric, or temperature demands); this makes them difficult to cultivate in the laboratory |
|
|
Term
|
Definition
[image]
have less complex growth requirements, and are easier to cultivate in the laboratory |
|
|
Term
|
Definition
[image]
"salt lovers", e.g. Vibrio chlorae, V. parahaemolyticus |
|
|
Term
|
Definition
growth occurs between 20-50*C … most pathogens are mesophiles & grow best at 35-36*C |
|
|
Term
thermophiles (obligate or facultative) |
|
Definition
"heat lovers"; grow at temperatures greater than 55*C |
|
|
Term
psychrophiles or cryophiles (obligate or facultative) |
|
Definition
grow at temperatures less than 20*C (think "cryo"genics, etc.) |
|
|
Term
|
Definition
[image]
can grow in the presence of O2 because they produce enzymes which detoxify superoxide radicals and hydrogen peroxide |
|
|
Term
|
Definition
[image]
can grow in the presence of O2 because they produce enzymes which detoxify superoxide radicals and hydrogen peroxide
Some examples of facultative anaerobic bacteria are Staphylococcus (Gram positive), Escherichia coli and Shewanella oneidensis (Gram negative), andListeria (Gram positive). Certain eukaryote phyla are also facultative anaerobes, including fungi such as yeasts and many aquatic invertebrates such asNereid (worm) polychaetes, for example. There are also circulating white blood cells that are classified as facultative anaerobes. These include neutrophils,monocytes and tissue macrophages. |
|
|
Term
superoxide dismutase (SOD) |
|
Definition
[image]
enzyme of aerobes that detoxifies superoxide anion (O2*-) |
|
|
Term
|
Definition
[image]
enzyme of aerobes that detoxifies H2O2 |
|
|
Term
|
Definition
[image]
require the presence of atmospheric O2 for growth, e.g. Mycobacterium tuberculosis |
|
|
Term
microaerophilic organisms |
|
Definition
[image]
require the presence of some O2 but NOT at atmospheric levels (reduced O2), e.g. Campylobacter |
|
|
Term
|
Definition
[image]
can grow in the presence or absence of O2 … many pathogens are facultative anaerobes, e.g. enteric bacteria |
|
|
Term
|
Definition
[image]
can survive in the presence of O2, e.g. Lactobacillus spp. |
|
|
Term
|
Definition
[image]
are killed by the presence of O2, they are lacking in the enzymes superoxide dismutase and catalase, e.g. Clostridium, Bacteroides, and others |
|
|
Term
|
Definition
an enzymatic process occurring in a membrane vesicle or sack; the function of which is to provide energy via Proton Motive Force for ATP synthesis (production) during the conversion (recycling) of NADH2 to NAD |
|
|
Term
aerobic respiration (aka oxidative phosphorylation) |
|
Definition
[image]
O2 is the terminal electron acceptor, which is reduced to water by the electron transport system … common among pathogenic microorganisms and humans |
|
|
Term
|
Definition
[image]
inorganic compounds (nitrate, sulfate, etc.) serve as terminal electron acceptors … this is significant especially for pregnant females, high levels of nitrites can cause methemoglobinemia (MetHb) especially in the fetus |
|
|
Term
|
Definition
simpler and less efficient than respiration … fermentation consists of catabolic pathways where organic compounds serve as electron donors and electron acceptors; substrates are partially oxidized generating end products which are 1,2,3,4 carbon compounds, as electron acceptor, and are excreted/released from the cell |
|
|
Term
dental carries (cavities) |
|
Definition
a fermentation process … bacteria like streptococcus mutans produce lactic acid, which demineralizes the tooth |
|
|
Term
acification of skin and vagina |
|
Definition
a fermentation process … bacteria like Lactobacillus sp. (produces lactic acid) and Propionibacterium acnes (produces propionic acid) all lower pH of tissues |
|
|
Term
|
Definition
enzyme responsible for recycling ferredoxin from the reduced to the oxidized form, in the fermentation process typical for many species of Clostridium |
|
|
Term
|
Definition
microbial enzyme that hydrolyzes urea, producing ammonia (NH4+) and CO2 |
|
|
Term
|
Definition
[image]
kidney stones … the more alkaline pH in the urinary tract, the more the Ca2+ and NH4+ ions in the urine can form salts which may precipitate out, accumulating in stones |
|
|
Term
|
Definition
[image]
phase in the growth cycle, in which there is no change in cell number |
|
|
Term
|
Definition
[image]
follows lag phase in the growth cycle … growth occurs at an exponential/logarithmic rate during this phase |
|
|
Term
|
Definition
[image]
the time required for a parent to divide into two daughter cells … also known as the doubling time |
|
|
Term
|
Definition
[image]
phase in the growth cycle which follows log phase and where no net increase in cell numbers occurs |
|
|
Term
|
Definition
[image]
defined as the phase which follows the stationary phase of the growth cycle, and where cell death begins to occur at a logarithmic rate |
|
|
Term
|
Definition
rapidly progressing … from the latin fulminare meaning "to strike with lightning" ... fulminant infections may be produced by bacteria with a short mean generation time ... may also refer to onset of disease (e.g. fulminant liver failure, fulminant meningitis) |
|
|
Term
|
Definition
bacteria with a long generation time generally produce chronic infections, a low Ag dose |
|
|
Term
|
Definition
the set of all chromosome(s) of an organism |
|
|
Term
|
Definition
complete listing of all genes present in an organism |
|
|
Term
|
Definition
complete listing of all physical characteristics that an organism expresses under a defined set of conditions |
|
|
Term
|
Definition
[image]
a DNA or RNA molecule that controls its own replication and is capable of self-duplication |
|
|
Term
extra chromosomal elements |
|
Definition
replicons that are present in a cell, excluding the host cell DNA, and including plasmids, baccteriophages (bacterial viruses) |
|
|
Term
|
Definition
[image]
plasmids are DNA molecules that are separate from, and capable of replicating independently of, the chromosomal DNA; they are considered replicons, capable of autonomous replication, although they use the bacteria's replication machinery ... plasmids are double stranded covalently closed circular DNA molecules which reside in the bacterial cytoplasm. So they are extra-chromosomal elements. |
|
|
Term
|
Definition
[image]
encode for a mechanism of plasmid transfer (sex pilus) |
|
|
Term
|
Definition
[image]
encode for drug resistance |
|
|
Term
|
Definition
ecnode for virulence factors |
|
|
Term
|
Definition
[image]
viruses (either DNA or RNA) which infect bacteria. Some bacteriophages can exist in a latent state in the bacterial cells. The viral DNA (prophage) either integrates into the host cell's chromosome or functions as a plasmid in the bacterial cytoplasm. |
|
|
Term
|
Definition
bacteria with latent phages (have prophages); in contrast with phages that go through only a lytic cycle (lyse bacteria) |
|
|
Term
|
Definition
the situation in which ALL cells in a population respond to environmental stimuli in the SAME fashion, and produce a new/altered phenotype via the expression of a gene(s) … no genotypic change is needed for this to occur … e.g. capsule production by the yeast Cryptococcus neoformans |
|
|
Term
|
Definition
ability of bacteria to detect the size of their own population; a system of stimulus and response correlated to population density; can be used to coordinate gene expression
Some of the best-known examples of quorum sensing come from studies of bacteria. Bacteria use quorum sensing to coordinate certain behaviors based on the local density of the bacterial population. Quorum sensing can occur within a single bacterial species as well as between diverse species, and can regulate a host of different processes, in essence, serving as a simple communication network. A variety of different molecules can be used as signals. Common classes of signaling molecules are oligopeptides in Gram-positive bacteria, N-Acyl Homoserine Lactones (AHL) in Gram-negative bacteria, and a family of autoinducers known as autoinducer-2 (AI-2) in both Gram-negative and Gram-positive bacteria. |
|
|
Term
|
Definition
when the genome (genotype) of one or more cells is/are altered … the acquisition of new genetic information occurs by two different processes -- mutation or horizontal gene transfer |
|
|
Term
|
Definition
alteration in nucleotide sequence of a gene; process of acquiring new genetic information that involves INTERNAL change of the genome |
|
|
Term
|
Definition
[image]
process of acquiring new genetic information that involves acquisition of a gene from EXTERNAL sources |
|
|
Term
|
Definition
[image]
mechanism of horizontal gene transfer … occurs when there is replacement of a portion of the recipient's genome are replaced by homologous chromosomal genes from another (donor) bacteria; recipient must be "competent," so it can incorporates free donor DNA into its genome, e.g. recombination |
|
|
Term
|
Definition
[image]
mechanism of horizontal gene transfer … when the source of external genetic information is a conjugative (transmissable) plasmid carrying new or altered genes (from donor cell) |
|
|
Term
|
Definition
[image]mechanism of horizontal gene transfer, where DNA is transferred from one bacterium to another by a virus or viral vector; does not require cell-to-cell contact (unlike conjugation) … transduction involves lysogeny (prophages), i.e. acquisition of bacteriophages (as a prophage, latent virus) |
|
|
Term
|
Definition
[image]
bacterial virus; any number of viruses that infect bacteria ... they do this by injecting genetic material (ssRNA, dsRNA, ssDNA, dsDNA) that was stored in their capsid into the bacteria ... phages are one of the most common and diverse entities in the biosphere |
|
|
Term
|
Definition
[image]
infects the bacterial host cell, replicates, then kills (lyses) the bacterium releasing the new progeny to injfect other cells … involved in transduction, form of horizontal gene transfer |
|
|
Term
|
Definition
[image]
infects the host bacterial cell, after which the phage has two options - either undergo the normal lytic cycle (infect, replicate, then lyse) or can become latent thus "lysogenizing" the bacterium (either by reamaining as plasmid in cytoplasm or by integrating/inserting into host cell DNA) |
|
|
Term
|
Definition
[image]
can remain latent inside bacterial host cell either by remaining as a plasmid in the cytoplasm or by integrating/inserting into the host cell DNA |
|
|
Term
|
Definition
[image]
when the recipient bacterial host cell is infected by a temperate virus … a bacterium exhibits a new phenotype due to the acquisition of a prophage (latent bacteriophage) which encodes for the new phenotype |
|
|
Term
|
Definition
used epidemiologically to determine common source of infecting organisms … plasmid DNA is isolated, purified, DNA fragments are separated by size; detection methodology involves staining = (+) positive match means strains of the same organism possess same number and size of plasmids; (-) negative match means strains with different number or sizes of plasmids, not epidemiologically related |
|
|
Term
polymerase chain reaction (PCR) |
|
Definition
[image]
PCR is the in vitro amplification of target DNA or RNA from an organism; the purpose is to amplify nucleic acid sequences which cannot be detected directly … i.e. standard for diagnosis of specific agents detection of Herpes simplex virus JC virus, enteroviruses, rabiesvirus in CNS |
|
|
Term
|
Definition
[image]
Microorganisms that are expected to be present, and that under normal circumstances do not cause disease, but instead participate in maintaining health, are deemed members of the normal flora.
Normal flora bacteria can act as opportunistic pathogens at times of lowered immunity. |
|
|
Term
selective anatomical distribution |
|
Definition
characteristic of natural flora (NF); microorganisms have specialized ecological niches (anatomical locations) in and on the body … due in part to attachment sites, nutritional needs, competition, inhibitory substances |
|
|
Term
|
Definition
[image]
indicators of fecal contamination and food; Gram-negative rods, facultative anaerobes |
|
|
Term
|
Definition
|
|
Term
|
Definition
when normal flora (NF) becomes opportunist (opportunistic infections, usually their virulence is low) … host suffers, microbes benefit |
|
|
Term
|
Definition
classical infectious disease; when an external microbe not part of normal flora causes damage to its (healthy) host |
|
|
Term
|
Definition
[image]
produced by Gram-negative organisms, is pyrogenic (fever-causing), is heat stable (survives autoclaving), does not form toxoids, broad spectrum of activity (affects a wide variety of animal species) |
|
|
Term
|
Definition
produced by Gram-positive and Gram-negative bacteria; polypeptides or proteins that are either secreted or cell-associated, can be chromosomal or plasmid-encoded or carried on temperate bacteriophages (lysogenic conversion), usually heat labile, can form toxoids (highly immunogenic) generally do not induce fever (not pyrogenic) |
|
|
Term
|
Definition
a microbial life form that is a harmful symbiont; the etiologic agent of an infectious disease |
|
|
Term
|
Definition
[image]
essentially always cause infection and/or disease in a specific host |
|
|
Term
|
Definition
infect and/or cause disease only in compromised hosts (immunosuppressed, malnourished, have cancer, etc.) … also can be normal flora (NF) that become pathogenic due to some changes in the host |
|
|
Term
|
Definition
[image]
microbial life form that essentially never cause disease, even if the host is severely compromised (e.g. lactobacillus) |
|
|
Term
|
Definition
the evolution of a disease within a host (the "course" of disease) |
|
|
Term
pathogenicity and virulence |
|
Definition
essentially interchangeable terms that describe the degree to which a pathogen causes disease |
|
|
Term
|
Definition
the degree of pathogenecity; degree to which a pathogen causes disease |
|
|
Term
|
Definition
determinants of virulence; any of a pathogens genetic, biochemical or structural features that enable it to produce disease in a host
virulence factors allow pathogens to colonize a host, evade immune responses, and obtain nutrition
Some virulence factors are intrinsic (capsule, endotoxin) while others are obtained from external (plasmids). LPS is the prototypical endotoxin; exotoxins include the tetanus toxin and the botulinum toxin |
|
|
Term
|
Definition
presence of microorganisms in a site of the body that does not necessarily lead to tissue damage and signs/symptoms of disease |
|
|
Term
|
Definition
effects of bacterial infection apparent to the infected person (the subjective side of describing and determining pain) … e.g. chills, pain, ache, soreness, irritation, nausea, malaise |
|
|
Term
|
Definition
the objective side of describing and determining pain/disease, such as temperature or blood pressure … examples = fever, antibodies in serum, blood pressure, heart beat, respiratory range, complete blood work |
|
|
Term
|
Definition
[image]
similar to colonization; refer to someone who is actually infected or has been previously infected with a pathogen, carries that pathogen with them as part of their normal flora (transmission potential), but does not exhibit disease manifestations referable to the pathogen (i.e. inapparent carriage; or in salmonella carriage) |
|
|
Term
|
Definition
|
|
Term
|
Definition
host not harmed, microbe benefits |
|
|
Term
|
Definition
host suffers, microbes benefit |
|
|
Term
|
Definition
measure of virulence; amount of organism that will infect 50% of susceptible animals |
|
|
Term
|
Definition
measure of virulence; amount of organism that will kill 50% of susceptible animals |
|
|
Term
inapparent (subclinical) or asymptomatic infection |
|
Definition
presence of pathogen; but no detectable clinical symptoms of infection (except seroconversion w/ antibodies does occur) |
|
|
Term
dormant (latent) infection |
|
Definition
[image]
pathogen is present; but not active or manifest |
|
|
Term
|
Definition
[image]
clinically apparent invasion and multiplication of microbes in body tissues, causing local tissue injury |
|
|
Term
|
Definition
microbial invasion subsequent to primary infection |
|
|
Term
|
Definition
two or more microbes infecting the same tissue |
|
|
Term
|
Definition
[image]
rapid onset (hours or days) and brief duration (days or weeks) |
|
|
Term
|
Definition
infection is not chronic but runs a rapid and severe, but less than acute, course; thus, it is intermediate between acute and chronic |
|
|
Term
|
Definition
infection w/ prolonged duration (weeks, months, or years) |
|
|
Term
|
Definition
infection confined to a small area or to an organ |
|
|
Term
|
Definition
infection disseminated to many body regions |
|
|
Term
|
Definition
|
|
Term
|
Definition
infection that occurs suddenly and intensely and are rapidly progressive |
|
|
Term
|
Definition
literally, an infection "on top of", as a result of, or in addition to the primary infection … often, these result from antimicrobial treatments … e.g. pt prescribed antibiotics for a UTI, and a yeast infection develops as a result |
|
|
Term
|
Definition
infection caused by more than one organism simultaneously |
|
|
Term
|
Definition
this is when two infections appear together, they are often interdependent but are always simultaneous … closely related to the term superinfection (all superinfections are coinfections) … e.g. approximately 80% of TB patients have HIV |
|
|
Term
|
Definition
a specific set of manifestations of damage referable to specific pathogen-host interactions … from the Old French meaning "away from the normal" … disease spectrum ranges from asymptomatic to fatal progression |
|
|
Term
|
Definition
[image]
disease comes from a unique combination of events involving a (harmful) agent, a (susceptible) host, all in the same (proper) environment … disease can be blocked at any three of these "sides" of the "triangle" |
|
|
Term
|
Definition
anything from innate or genetic susceptibility to disease, or psycho-social factors that affect the "host" angle of the epidemiological triad … interventions here would include hygiene, quarantine, immunization, etc. |
|
|
Term
|
Definition
anything from the availability of vectors, to the weather/seasonality, to the existence of reservoir hosts that makes up the "environment" angle of the epidemiological triad … interventions here would include handling/treatment of water/waste, appropriate food handling, controlling temperature, adequate ventilation, etc. |
|
|
Term
|
Definition
anything about the infectious agent such as persistence or survivability, toxins or virulence factors, that affects the "agent" angle of the epidemiological triad … interventions here include sterilization and disinfection measures |
|
|
Term
|
Definition
a continual source of infection … can be living (humans w/ disease) or non-living (soil or water or food) |
|
|
Term
|
Definition
involves either direct contact (sexual, kissing) or indirect contact (by vehicle such as water or food or soil or blood) |
|
|
Term
vehicle transmission, by a medium |
|
Definition
involves transmission via water or food or air or soil or blood or fomite |
|
|
Term
|
Definition
any inanimate object or substance capable of carrying infectious organisms |
|
|
Term
vehicle transmission, by vector (live carrier) |
|
Definition
such as in the case with transmission via arthropods … either a biological vector (part of the life cycle of the pathogen, in saliva or in feces) or by a mechanical vector (passive transport of a pathogen on a vector's feet or other body part) |
|
|
Term
|
Definition
those infections spread from animals (their natural reservoir) to humans as a receptive/susceptible and propagating host … zoonoses tend to be more serious (morbidity) and often fatal (mortality) in humans than in their natural animal reservoirs |
|
|
Term
non-communicable infectious diseases |
|
Definition
are not transmitted from one person to another; normal flora can be a source, so can preformed microbial toxins or environmental pathogens; but there is no person-to-person transmission |
|
|
Term
communicable (person-to-person) infectious diseases |
|
Definition
diseases that are transmitted person-to-person … can be spread horizontally (airborne, fecal-oral, bloodborne, etc.) or can be spread vertically (mother to fetus) |
|
|
Term
|
Definition
refers to the indirect effect of protection from infection of otherwise susceptible members of a populations and the population as a whole (herd) as a result of the presence of immune individuals … varies with different infectious agents … for most infectious diseases, only a small fraction of the population (herd) can be left unvaccinated for herd immunity to be effective |
|
|
Term
|
Definition
in herd immunity, immune individuals provide a firewall against the spread of an infectious disease from person-to-person |
|
|
Term
incubation period (incubation time) |
|
Definition
the time between exposure to a pathogen and the appearance of the first symptoms of disease
[image] |
|
|
Term
|
Definition
administration of antimicrobials prior to onset of symptoms
antibiotics, for example, can be administered to patients with disorders of immune system dysfunction, to prevent opportunistic infection |
|
|
Term
|
Definition
passive or even active immunization prior to the onset of symptoms |
|
|
Term
|
Definition
number of new occurrences of disease, injury, or death in the study population during the time period being examined |
|
|
Term
|
Definition
if the incidence rate (new occurrences) is consistently higher during a specific time of year, e.g. influenza demonstrates winter seasonality |
|
|
Term
|
Definition
the total number of existing cases with respect to the entire population (100%) … prevalence = incidence (new cases) + old cases |
|
|
Term
|
Definition
measures the total number of deaths in a population due to a certain disease |
|
|
Term
|
Definition
measures the total number of persons afflicted with infectious diseases |
|
|
Term
|
Definition
the rate at which infection or disease is present - a certain constant rate (the endemic rate) |
|
|
Term
|
Definition
[image]
a significant (and usually sudden) increase above the endemic and sporadic rate of a disease … could be hours, days, months |
|
|
Term
|
Definition
an epidemic where all individuals are exposed to one specific source |
|
|
Term
|
Definition
an epidemic where all individuals are exposed to a specific source at a particular time |
|
|
Term
propagative or progressive epidemics |
|
Definition
indicates a transmissable or communicable disease |
|
|
Term
|
Definition
[image]
a global epidemic (above the normal global endemic rate) |
|
|
Term
|
Definition
occasional cases of a disease at irregular intervals in random locales |
|
|
Term
|
Definition
epidemic zoonoses … above the endemic/sporadic rate |
|
|
Term
|
Definition
endemic zoonoses … within the range of endemic/sporadic observed rate |
|
|
Term
|
Definition
an attribute, characteristic, agent, etc. that is, or is suspected to be, related to the occurrence of a particular disease … help to identify populations at risk … thus can occasionally rule-out or rule-in certain diseases … more often used to rank-order possibilities in synthesizing a differential diagnosis from most likely to least likely ... e.g. age, gender, occupation, geography, etc. |
|
|
Term
|
Definition
Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA molecules, 20-25 nucleotides in length, that play a variety of roles in biology. The most notable role of siRNA is its involvement in the RNA interference (RNAi) pathway, where it interferes with the expression of a specific gene. |
|
|
Term
|
Definition
A type species is the species to which the name of a genus is permanently linked; it is the species that contains the biological type specimen(s) of the taxon. This is an important concept whenever a taxon containing multiple species must be divided into more than one genus; the type species automatically assigns the name of the original taxon to one of the resulting new taxa, thus reducing the potential for confusion. |
|
|
Term
How do plasmids differ from viruses? |
|
Definition
Plasmids are considered replicons, capable of replicating autonomously within a suitable host. Plasmids can be found in all three majordomains: Archaea, Bacteria, and Eukarya.Similar to viruses, plasmids are not considered by some to be a form of life. Unlike viruses, plasmids are naked DNA and do not encode genes necessary to encase the genetic material for transfer to a new host, though some classes of plasmids encode the sex pilus necessary for their own transfer. Plasmid host-to-host transfer requires direct, mechanical transfer byconjugation or changes in host gene expression allowing the intentional uptake of the genetic element by transformation.Microbial transformation with plasmid DNA is neither parasitic nor symbiotic in nature, because each implies the presence of an independent species living in a commensal or detrimental state with the host organism. Rather, plasmids provide a mechanism for horizontal gene transfer within a population of microbes and typically provide a selective advantage under a given environmental state. Plasmids may carry genes that provide resistance to naturally occurring antibioticsin a competitive environmental niche, or the proteins produced may act as toxins under similar circumstances. Plasmids can also provide bacteria with the ability to fix elemental nitrogen or to degrade recalcitrant organic compounds that provide an advantage when nutrients are scarce. |
|
|
Term
latent, reactivating infection |
|
Definition
[image]
e.g. herpes simplex virus |
|
|
Term
|
Definition
w/ periods of dormancy
[image]
e.g. measles virus (SSPE); human immunodeficiency virus (HIV) |
|
|
Term
|
Definition
A toxoid is a bacterial toxin (usually an exotoxin) whose toxicity has been weakened or suppressed either by chemical (formalin) or heat treatment, while other properties, typically immunogenicity, are maintained.
Toxoids are used as vaccines because they induce an immune response to the original toxin or increase the response to another antigen. For example, the tetanus toxoidis derived from thetetanospasmin produced by Clostridium tetani. The latter causes tetanus. Botulin is produced by Clostridium botulinum and it causes the deadly disease botulism. |
|
|
Term
|
Definition
[image]
Septum is a small fissure formed during bacterial cell division ... Bacteria reproduce by an asexual process called binary fission. First, the DNA replicates and the cell elongates. In the middle of the elongated cell, a septum forms and this develops in to a cell wall that divides two seperate cells. |
|
|
Term
transpeptidase or penicillin binding proteins (PBP) |
|
Definition
the enzyme responsible for completing the final cross-linking (transpeptidation) process in the synthesis of peptidoglycan |
|
|
Term
Why are chemotherapeutic inhibitors of protein and/or peptidoglycan synthesis more effective against fast-growing than against slow-growing organisms? |
|
Definition
Inhibition of peptidoglycan synthesis inside an actively-dividing cell results in osmotic lysis; so if an organism is dividing more frequently, it will be lysed more frequently by the antibiotic
many antimicrobials utilize this - e.g. the penicillins, the cephalosporins, the carbapenems |
|
|
Term
|
Definition
The host range or host specificity of a parasite is the collection of hosts that an organism can utilize as a partner. In the case of human parasites, the host range influences the epidemiology of the parasitism or disease. |
|
|