Term
|
Definition
protein A
-binds IgG by FC portion -> protects bacteria from immune surveillance
catalase
-inhibition of oxidative burst -> catalase breaks down hydrogen peroxide
hyaluronidase
-breaks down hyaluronic acid
TSST
-superantigen
primary carriage in the nose |
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Term
|
Definition
-cover membrane attack complex (MAC) targets
-salmonella typi -> persists in gallbladder |
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Term
|
Definition
found in vagina during child-bearing years
-production of estrogen helps this organism to colonize
-primary org |
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Term
|
Definition
part of lipoteichoic acid mimics platelet activating factor (PAF)
-causes engulfment of org. by binding to PAF receptors -> brought into lung epithelium and endothelium of blood vessels
-cross epithelial/endothelial borders -> get from lungs (pneumonia) to blood stream (bacteremia) to brain (meningitis)
capsule
-covers cell wall teichoic acid that activates complement
cleaves c3b, decreasing opsonization?
release hyaluronidase?
opportunistic infection when people have a splenectomy
pneumovax = vaccine |
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Term
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Definition
-type iv pili -> grappling hook (extension, tethering, and then retraction), also called twitching motility
-cut sIgA into little pieces
-alters its outer membrane proteins (antigenic variation)
-endemic infection |
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Term
| Corynebacterium diphtheriae |
|
Definition
diptheria toxin
-produced when levels of iron are low in the organism -> thought to be a way to release iron from killed host cells
-disrupts cellular protein synthesis -> ADP-ribosylates elongation factor-2
-single A and single B subunits -> whole molecule taken into cell, acidification releases A from B
-stops protein synthesis cold -> cell dies
-thick, leathery membrane of dead cells
-can cause problems in cardiac tissue
-doesn't invade tissue |
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Term
|
Definition
-Staphylococcus epidermidis
-Corynebacterium sp.
-Propionobacterium acnes |
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Term
| nose = primary carriage site: |
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Definition
|
|
Term
| nasopharynx = transient carriage site for: |
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Definition
-streptococcus pneumoniae
-neisseria meningitidis
-haemophilus influenzae |
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Term
| site where NF changes ONCE during lifetime |
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Definition
|
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Term
|
Definition
-Streptococcus mutans -> tooth decay
-anaerobes -> periodontal disease |
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Term
|
Definition
-Helicobacter pylori (stomach)
Colon
-mostly anaerobes (most orgs here of the entire GI tract)
-Bacteroides sp.
-Clostridium sp.
-Enterococcus sp.
-Candida albicans
-Escherichia coli |
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Term
| site where NF changes TWICE during lifetime |
|
Definition
female genital tract
-Lactobacillus sp. help keep other orgs out during childbearing years
-normal flora derived from skin, colon
-during childhood and menopause -> slightly alkaline
-during child bearing years -> pH of 3.6-4.5
-estrogen increases -> glycogen produced -> lactobacilli feed on glycogen and produce lactic acid = during child-bearing years
-estrogen drops during menses, thus, chance of yeast infection/STDs increases |
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|
Term
quintessential opportunistic pathogen that can invade virtually any tissue
-leading cause of hospital-acquired gram negative infections (from exogenous source) |
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Definition
|
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Term
| opportunistic pathogens - immune disorder |
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Definition
| pneumocystis in HIV/AIDS patients |
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Term
| opportunistic pathogens - functional disorder |
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Definition
| encapsulated Streptococcus pneumoniae after splenectomy |
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Term
| opportunistic pathogens - inoculation into unusual site |
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Definition
| Clostridium tetani into puncture wound |
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Term
| opportunistic pathogens - antibiotic treatment |
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Definition
-vaginal yeast infections when normal flora reduced
-Clostridium dificile bowel infection |
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Term
| 5 steps in infectious disease |
|
Definition
1. adherence
2. multiplication
3. invasion (optional)
4. resistance to host defenses
5. tissue damage |
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|
Term
| type iv pili (twitching motility) |
|
Definition
|
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Term
|
Definition
protein F (non-pili adhesin)
-binds to fibronectin on mucosal surfaces
streptolysin O
-kills phagocytes
cleaves C3b
produces hyaluronidase |
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Term
|
Definition
| -adherence to host cells and each other |
|
|
Term
| women with recurrent UTIs |
|
Definition
| have receptors that bind E. coli especially well |
|
|
Term
| integrins for polio virus |
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Definition
|
|
Term
| mechanisms to avoid mucosal defenses |
|
Definition
-immobilize or destroy host cell cilia
-produce IgA protease |
|
|
Term
| exploitation of host internatlization mechanisms |
|
Definition
-use macros for transportation
-"forced" phagocytosis into non-phagocytes |
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Term
|
Definition
-bind to host cell integrins
-binding triggers actin, causes engulfment |
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Term
| cause host cell fusion -> form syncytia (giant multinucleated cells) |
|
Definition
-Herpes simplex
-Herpes zoster
-measles virus (paramyxovirus) |
|
|
Term
| traverse cell membranes into adjacent cells |
|
Definition
-Shigella sp.
-Listeria monocytogenes (actin tails) |
|
|
Term
| budding from one cell to another |
|
Definition
| measles virus (paramyxovirus) |
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Term
| disruption of cytokines and chemokines |
|
Definition
-vaccinia virus -> binds TNF, IFNs -> decreases inflammation
-epstein-barr virus -> produces IL-10 homolog that shuts down immune response |
|
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Term
|
Definition
-hep B, influenza, measles virus -> immune malfunction
-measles suppresses IL-12, thus increases TB outbreaks (prevents activations of TH1 cells impt. in TB immunity) |
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Term
|
Definition
|
|
Term
| resistance to antibacterial substances in secretions (lysozyme, LC fatty acids) |
|
Definition
-broken down by some orgs
-others have developed resistance |
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Term
|
Definition
-orgs produce siderophores
-orgs produce receptors for host iron binders |
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Term
|
Definition
covers complement activating sites with sialic acid
coats self with circulating IgA antibodies
-prevents binding of IgM and IgG which normally activate complement |
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|
Term
| cleaves C5a -> prevents neutrophils from being called in |
|
Definition
|
|
Term
| cleaves C3b, decreasing opsonization |
|
Definition
|
|
Term
| cover membrane attack complex targets |
|
Definition
-E. coli
-Shigella
-Salmonella
-long polysaccharide chains on LPS trap MAC -> rough (shorter LPS chain) strains are less pathogenic |
|
|
Term
| cut sIgA into little pieces |
|
Definition
|
|
Term
|
Definition
| sleeping sickness trypanosomes |
|
|
Term
mutation (antigenic drift)of NA/HA
recombination (antigenic shift) |
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Definition
|
|
Term
| inhibit phagocyte recruitment/action |
|
Definition
inactivate c3a and/or c5a
theta toxin of Clostridium perfringes (gas gangrene) paralyzes PMNs
Yersinia pestis injects enzyme that prevents macrophage uptake and proudction of proinflammatory cytokines
kills phagocytes
-Bacillus anthracis produces a lethal toxin
-Streptolysin O of Streptococcus pyogenes |
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Term
|
Definition
-prevents opsonization by complement
-helps repel negative surface of phagocytes with negative charge of capsule |
|
|
Term
| survival inside the phagosome of phagocytes |
|
Definition
Shigella flexneri
-produces enzymes that releases it from the phagosome
-avoids antibodies and complement as it grows inside the cytoplasm of phagocyte
Legionella pneumophila
-inhibits phagosome/lysosome fusion in macrophage
-covers vacuole with ribosomes to look like ER
Leishmania parasites
-resistant to some lysosomal enzymes
-secrete enzyme inhibitors for others
Staphylcoccus aureus
-inhition of oxidative burst by producing catalase
Mycobacterium tuberculosis (master evader)
-inhibits phagosome-lysosome fusion
-suppresses O2- production of oxidative burst
-prevents acidification of phagolysosome |
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|
Term
|
Definition
cholera toxin
-5B and 1A moeity -> only A1 enters
-ADP-ribosylates protein regulating cAMP synthesis -> cAMP accumulates -> causes loss of control of iron flow
-massive watery diarrhea (24+ liters/day) -> loss of sodium, potassium, water, and hco3
-treat with IV fluids
-antibiotics not always needed
-rice water stool |
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Term
|
Definition
shiga toxin
-A-B toxin, but not excreted from bacteria -> released when cells lyse
-no ADP-ribosylation
-stops host protein synthesis -> cleaves host cell 60s ribosomal rna, preventing protein elongation
-causes mucosal damage, bloody diarrhea
-if it gets into bloodstream, may cause hemolytic uremic syndrome |
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|
Term
|
Definition
org rarely moves from site of infection
tetanus toxin
-A-B toxin -> acts at a distance
-taken into alpha motor neurons and travels up axons into spinal cord
-blocks release of inhibitory NTs (glycine and GABA)
-muscles constantly stimulated (tetany) |
|
|
Term
| membrane disrupting toxins |
|
Definition
cytotoxins, hemolysins
-disrupt integrity of host cell membranes
some insert into membrane
-not enzymatic action
-low conc. -> inhibit cell function
-high conc. -> can lyse cells by osmotic shock
some have phospholipase activity
-remove polar head groups from membrane lipids -> destabilization of membrane causes cell lysis
-e.g. lecithinase of clostridium perfringes
often less cell-type specific than A-B toxins
-targets found on many cells |
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|
Term
|
Definition
facilitate invasion or provide nutrients
lack actual cytotoxicity
-not true toxins, but do induce tissue damage
Ig and complement proteases
"spreading factors" aid in invasion |
|
|
Term
| proteolytic toxins (examples) |
|
Definition
hyaluronidase
-Staphylococci and streptococci
collagenase
-Clostridium perfringes
phospholipase C
-Pseudomonas aeruginosa
-hydrolyzes phospholipds to obtain phosphate |
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|
Term
|
Definition
Potent polyclonal stimulators of T-cell activation and proliferation
Nonspecifically bind helper T-cells to antigen-presenting cells
Cause excessive IL-2, TNF, IL-1 production
Fever, vomiting, malaise, shock
Examples - Staphylococcal TSST, enterotoxins |
|
|
Term
| chronic persistent infection |
|
Definition
Salmonella typhi – cause of typhoid fever
-organism can persist in gall bladder
-leads to asymptomatic shedding in feces, urine
-person can infect many others = 1937 London case/water pipe worker urinates on ground = contaminates water = 310 infections/43 fatalities |
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|
Term
| Latent Persistent Infections |
|
Definition
Mycobacterium tuberculosis
-organisms persist in lungs
-reactivation may cause acute disease
Herpes viruses notorious for latency
-Herpes zoster goes dormant, not infectious
-CMI weakens with age, breaks latency
-person develops shingles
-becomes infective for other people again |
|
|
Term
| chronic disease development -> diseases manifesting due to previous infection with organism |
|
Definition
Hypothesized connection for centuries
difficult to prove without modern techniques
Helicobacter pylori – ulcers - 1982
Borrelia burgdorferi – chronic Lyme arthritis
Streptococcus pyogenes - rheumatic fever
Systemic lupus, Crohn’s disease, multiple sclerosis, diabetes? |
|
|
Term
|
Definition
Infections and malignant transformations
result of viral infections
Mononucleosis and Burkitt’s lymphoma (1956)
-Epstein-Barr virus
-chronic malaria may play secondary role
Hepatitis B and C virus
-predispose to hepatocellular carcinoma
-Hep B vaccine - 1st vaccine to prevent cancer
Human papillomavirus and cervical cancer |
|
|
Term
| Non-Communicable Infections |
|
Definition
Infections by members of normal flora
e.g., Candida oral thrush in AIDS patients
Food poisoning due to pre-formed toxins
e.g., Staphylococcal food poisoning
Infections caused by common source
e.g., Legionnaire’s disease
Infections by organisms normally found in environment
e.g., C. tetani spores from soil inserted into anaerobic tissue wound |
|
|
Term
|
Definition
Saliva/respiratory route
-usually pathogens that infect respiratory tract
-mononucleosis - saliva (kissing disease)
-common cold - respiratory secretions
Even talking creates aerosols
-pronouncing “f, p, t, and s” = 268 orgs/min
Fecal/oral route
-organisms leave the gastrointestinal tract
-transmission in food, water, fomites
-usually intestinal pathogens
-Salmonella sp., Shigella sp.
Urinary spread uncommon
-occurs in typhoid fever and leptospirosis
Skin to skin
-Papillomavirus – warts
-may use fomites
-skin scales can remain infective long time (Athlete’s foot – months-years)
Eye to eye - conjunctivitis
-e.g., Haemophilus influenzae
-mostly through hands or fomites (towels, tissues, doorhandles, etc.)
Blood-borne - requires inoculation
-Hepatitis B, Hepatitis C viruses
-Human immunodeficiency virus
Venereal
-HIV, Hepatitis B, Hepatitis C viruses
-N. gonorrhoeae, Herpes simplex 2
-Chlamydia, Trichomonas
Vertical transmission
-mother to child
-Rubella, AIDS, syphilis
-could be transplacental or during birth
-some passed in breast milk
Horizontal transmission
-typical transmission from one person to another |
|
|
Term
|
Definition
-number of new cases within specified time period
-how fast is it progressing through population? |
|
|
Term
|
Definition
-total number of cases in population at given time
-how common is it in the population? |
|
|
Term
| terms that describe infections in a population |
|
Definition
Endemic - present at low but constant level = in this country = gonorrhea
Epidemic - prevalence of infection higher than usually found in that population = in this country in winter = influenza
Pandemic - widespread (sometimes worldwide) infection with high attack rate = H1N1 flu in 2009 (wide distribution/high attack rate); AIDS |
|
|
Term
|
Definition
lecithinase of clostridium perfringes -> phospholipase activity
-remove polar head groups from membrane lipids -> destabilization of membrane causes cell lysis
lecithinase of clostridium perfringes
theta toxin of Clostridium perfringes (gas gangrene) paralyzes PMNs
collagenase |
|
|
Term
|
Definition
quintessential opportunistic pathogen that can invade virtually any tissue
-leading cause of hospital-acquired gram negative infections (from exogenous source)
type iv pili (twitching motility)
phospholipase C
cleaves C5a -> prevents neutrophils from being called in |
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