Microbiology Test 2

Front 1

Old Problems, New Challenges

Back 1

-infectious disease were the leading cause of US death (pneumonia, diarrhea, TB) until the mid-20th century due to better sanitation and antibiotics
-sulfonamides (1935) and penicillin (1940s)
-In recent years these ID have made a comeback (TB) and are still devastating in 3rd world countries

Front 2

Types of Bacteria Outbreaks

Back 2

-E. Coli prevalent in the US, especially O157:H7 - 200 deaths/yr
-Flesh eating A Streptococci has a mortality rate of 50%, came back in 80s
-Re-emerges of TB
-Always new pathogens like lyme disease and legionnaires disease. Others include S. aureus and C. jejuni

Front 3

Normal Microbial Flora

Back 3

-microorganisms frequently found in health people; include bacteria, fungi, protozoa, and small insects
-Different body parts are colonized by different species of normal flora, Ex - skin, respiratory tract, GI tract, urinary tract, genitals
-Tissues that are sterile include blood, CSF, synovial fluid, urinary tract, peritoneum, deep tissue

Front 4

Factors Determining Nature of Normal Flora

Back 4

-normal flora in a continued state of flux due to age, diet, hormone state, health, sanitation, and hygiene..examples
1) Newborns - GI sterile at birth but changes when food introduced. If given breast-milk lactic acid streptococci and lactobacilli invade, if given bottle milk then it's more mixed
2) In 10% of people pathogens like meningococcus and pneumococcus are normal throat flora
3) Some normal flora in healthy people are pathogens in kids or immune-compromised people. Example is S. pyogenes which causes Scarlet fever in kids
4) Normal flora can cause disease if introduced to the wrong place (usually bloodstream).
a) Streptococci in the mouth can cause endocarditis if in blood/heart
b) E. Coli in GI can cause urinary tract infections if in this area
5) Normal flora can cause clinical problems. Streptococci are associated when plaque formation under certain circumstances

Front 5

Benefits of Normal Flora

Back 5

1) Protect against infection with virulent microorganisms and stimulate immune response - they produce anti-biotic molecules and digest nutrients in a competitive manner
2) Help metabolize certain foods and balance immunity
3) Provide essential vitamins and growth factors like vitB and vitK

Front 6

Types of Bacterial Infections

Back 6

1) Exogenously acquired - occurs from microorganisms not normally found in healthy host, once they enter body problem occurs. They are known as primary pathogens and cause a primary infection
2) Endogenously acquired - happens through microorganisms part of our normal flora under 3 conditions
1) normal balance disrupted
2) put into wrong (sterile) site
3) host is immunodeficient
-They are opportunistic pathogens and cause of opportunistic infection

Front 7

Terminology

Back 7

1) Colonization - bacteria finds niche in body and survives
2) Infection - pathogenic bacteria becomes established in the body
3) Disease - a infection that produces symptoms
4) Virulence - ability of a bacteria to cause infection
5) Virulence factor - How the bacteria causes the disease

Front 8

Transmission of Bacteria

Back 8

1) Inhalation - inhaled by droplets or dust in air. Example is M. tuberculosis and Legionella
2) Inhgestion - Brought into water and food. Prevent washing away by developing adhesions. Include Salmonella, Shigella, enterotoxigenic E. Coli, Chlorerae (diarrhea), and S. typhi (typhoid fever). Sanitation prevents
3) Cross Epithelial Barriers - Enter through bites, cuts, and wounds. Example is malaria through a bite and lyme through a tick. Use insect control
4) Sexual Transmission - Examples are Gonorrhoeae, Chlamydia, Treponema pallidum

Front 9

Primary Defense Against Bacteria

Back 9

1) Eyes - tears have lysozyme, IgA, and lactoferrin
2) Nasopharynx - resident microflora and stuff in eyes, mucus
3) Lungs - alveolar macrophages
4) Mouth - sloughing cells, saliva, stuff in eyes
5) Stomach - low pH, proteolytic enzymes
6) GI Tract - fast flow, mucus, resident microflora (colon)

Front 10

Inoculum Size

Back 10

-the number of microorganisms that must be in the host to cause a infection
-The infectious dose is represented as ID50.
-Tuberculosis is low with 1-10 while S. typhi is high with 10,000

Front 11

Koch Postulation

Back 11

-allow us to link specific bacteria to a particular disease
OLD MODEL:
1) microorganism found in all cases of the disease
2) Can be grown in culture
3) When culture put in healthy animal the disease occurs
4) Can be recultured from this lesions
Problems:
1) oportunistic pathogen does not cause disease in healthy host
2) Some bacteria can't be cultured in vitro
3) No animal model for some bacteria and if found recently, human test is unethical

New Molecular Version of Koch Postulation
1) Phenotype of disease associated with a gene found in bacteria strains that cause disease but not avirulent ones
2) Inactivation og gene reduces virulence while cloned gene into avirulent makes it virulent
3) Virulent gene always expressed in bacteria at some point during infectious process

Front 12

Major Group of Pathogenic Bacteria

Back 12

1) Taxonomy - Named by genus and species. Variety within species is called a strain. Differences between strains identified by serological differences
2) Major Groups - Major way to distinguish is by a gram stain which test permeability properites
G+ - purple
G- - pink
-major 4 bacteria are G+ rod/cocci and G- rod/cocci - all equally represented in normal flora.
-Pathogens not equally divided. G+ cocci and G- rods most common pathogens
3) Special Bacteria
1) Acid-Fast - include myocbactierium. Named cause must be stained by a special procedure. Their waxy envelope only penetrated by dyes treated with detergents. Special procedure is Ziehl-Neelsen technique
-ZN technique stains a colony with red dye fuchsin (with detergents) and then HCL which removes stain from all bacteria except acid fastr
b) Another special group is Spirochetes like B. burgdorferi and T. pallidnum. You need dark-field microscopy to visualize

Front 13

Diphtheria

Back 13

Name: C. diphtheria
Type: Gram positive, club-shaped rod, aerobic, non-spore forming
Epi: Used to be a very fatal pediatric disease but less so now because of immunization. Only human host
Symptoms: After diphtheria colonization of the throat through horizontal trnasmission (inhalation of aerosols from another person), the respiratory symptoms start within the week. You get sore throat, fever, and loss of apatite. This leads to a thick pseudomembrane in the back of the throat and it can lead to breathing problems, irregular heartbeat, and coma is introduced to the nervous system

Front 14

Diphtheria Virulence

Back 14

-known as an A-B toxin because toxin is a single peptide, cleaved to form an A-chain and B-chain united by a disulfide bond
-A has 1 functional domain while B has 2 function domains (3 total)
A: catalytic does ADP-ribosylation and inactivation of E2F translation factor
B: Binds cell surface receptor for endocytosis (B) and helps translocate A-chain into the cytoplasm (T)
1) B-chain binds to a receptor and the toxin enters via endocytosis
2) In the endosome A and B are completely separated. B inserts into the membrane and helps release A
3) A-chain ADP-ribosylated EF-2 which is needed for protein synthesis. Without the cell dies

Front 15

Diphtheria Dangers and Treatments

Back 15

-A single A-chain molecule can kill a cell
-Due to toxicity it is targeted for therapeutic purposes like killing tumor cells by adjusting the B-chain to target the enemy
Treatment
1) If infected but not immunized you can give antibodies which neutralize the toxin (passive immunity). Made in horses
2) You can give antibiotic with penicillin or erythromycin to kill it
3) Give a DPT vaccination which allows for a quick Ab increase if infected. Great vaccine without side effects and protects for a long time

Front 16

DPT

Back 16

-very effective vaccine against 3 major pathogens
1) Diphtheria toxoid - toxin inactivated with formaldehyde
2) Pertussis - heat killed Bordetella pertussis
3) Tetanus toxoid - toxin inactivated with formaldehyde

Front 17

Pertussis

Back 17

ETI: Bordetella pertussis is a gram-negative, aerobic rod. It causes the respiratory disease whooping cough
EPI: It is a endemic worldwide but less so in the US due to a vaccine. In recent years due to side effects vaccine not given and pertussis increased. Recently a new acellular vaccine given. Tri-vaccine now DAP
Symptoms: Infected by inhaled aerosols which become attached to ciliated epithelial cells on the upper respiratory tract. 4 stages
1) 7-10 day incubation
2) 1-2 weeks of catarrhal with runny nose, fever, sneezing, anorexia, and malaise
3) 2-4 weeks of paraxymal with whooping cough, vomit, leukocytosis
4) 3-4 weeks of pneumonia, seizure, and brain swelling

Front 18

Pertussis Virulence

Back 18

-Uses many adhesins to attach to respiratory mucosa. Also has a endotoxin which not only helps bind it to the cell, it also has a role inside the cell
1) Adherence - Uses adhesins to bind and colonize on the ciliated epithelial cells. Uses filamentous hemagglutinin (Fha) and pertussin toxin (Ptx) mainly, but also uses pili and pertactin
2) Pertussin toxin - Is an A-B toxin. It is a hetero-hexamer with one copy of subunits 1,2,3,5 and 2 copies of 4. S2 and S3 help bind initially and bring the enzymatic domain S1 into the cell.
3) S1 - Similar to diphtheria toxin, it does ADP-ribosylation on a adenylate cyclase-couple G protein. This deregulates the adneylate cyclase so it is always on making tons of cAMP. cAMP inhibits neutrophil action

Front 19

Pertussis Treatment

Back 19

-antibiotic erythromycin activity given later on does not lessen symptom duration but can lessen the infectivity and spread of the disease
-best treatment is a vaccine

Front 20

Streptococci and Staphylococci

Back 20

-both around gram positive cocci
Differences:
1) Colony Morphology - Strept grow in chains like a string of pearls whereas staph grow in grape-like clusters
2) Catalase - Only staph are catalase positive. By adding hydrogen peroxide to their colony you can see oxygen bubbles
3) Hemolysis - Lysis of RBC breaks strep into 3 groups
4) Coagulase - Only in Staph aureus

Front 21

Staphylococci Introduction

Back 21

examples: epidermidis is frequent on skin, aureus is pathogenic
-S.aureus are golden and produce coagulase. This enzyme helps them clot plasma and can be clumped in large aggregation when treated with serum

Front 22

Staphylococcal Disease

Back 22

-cause disease by toxin production or invasion and destruction of tissue
-each toxin diseased listed is done by a different toxin
1) Abcess - Infection leads to a pus-filled abcess. Known as a boil or furnucle in the skin, or a carbuncle is many connected. After acute inflammatory reaction neutrophils migrate to the aureus site. Aureus are able to kill neutrophils which leads to a release of lysosomal enzymes and this damages the surrounding tissue
2_ Staphylococcal Scalded Skin Syndrome (SSSS) - Affects kids and caused by a exfoliatin toxin. Leads to perioral erythema which includes blisters, epithelium desquamation. Usually not fatal

Front 23

Staphylococcal Disease 2

Back 23

3) Toxin Shock Syndrome (TSS) - Disease initiated by aureus growth in vagina or wound and release of toxin in blood stream. This leads to fever, sunburn like rash, hypotension, and a macular rash. Involves organ systems and skin desquamation.
-outbreak in 1980s due to super absorbent tampons. These tampons remove lactobacilli from vagina normal flora and reduced oxygen environment invites S. aureus. Gets toxin into the blood stream
4) Food Poisoning - Common food illness, passed through processed meats. Heat kills the bacteria but not the enterotoxin A toxin leading to vomitting, diarrhea (no blood) and ab pain

Front 24

Staphylococcal Virulence Factors

Back 24

1) Protein A - On the surface. It binds to IgG Fc domain inactivating it to prevent antibody-mediated host immune clearance
2) Leukocidin - Kills exposed white cells like in abcesses
3) Toxic Shock Syndrome Toxin-1 (TSST-1). It is a superantigen. It binds MHC class II on APCs as well as T-cell receptor. By forming a bridge between these proteins it allows an APC to stimulate tons of T-cells. This overstimulation may lead to either excess cytokines or endothelial cell damage leading to hypotension. Either way it leads to shock

Front 25

Staphlococcal Treatment

Back 25

-very drug resistant, penicillin does not work
-vancomycin is the LAST antibiotic used for hospital staph infection
-can use penicillinase-resistant penicillin derivates like nafcillin and oxacillin
-Can combine sulfa drugs and minocycline or rifampin

Front 26

Streptococci Classification

Back 26

1) Hemolysis pattern by adding blood to agar
a) alpha - partial hemolysis and hemoglobin reduction leads to green around colonies
b) beta - clearing around colonies due to complete hemolysis. Most pathogenic
c) gamma - no clearing zone, no hemolysis
2) Lancefield Group: serological classification that divides strains based on cell wall polysaccharides. Divided into A-T with the most virulent being in group A, known as Streptococus pyogenes
3) Viridans - Given to Strep with no lancefield antigens. Usually include alpha or gamma hemolytic strep. Are usually large present in the oropharynx normal flora and are of low virulence. Include S. mutans, responsible for dental caries

Front 27

Streptoccucus Pyogenes Disease

Back 27

-Lancefield A, beta hemolytic very virulent strain
1) Strep Throat - most common cause of pharyngitis which occurs 2-4 days after exposure
2) Scarlet Fever - Occurs during sore throat. During pharyngitis the S. pyogenes is lysogenized by a temperate bacteriophage that stimulates production of a exotoxin. 1-2 days later the patient gets a erythematous rash (skin redness) on the chest and extremities and a strawberry tongue. Used to be a major child killer but not rate since antibiotics
2) Streptococcal toxic shock syndrome -Similar to TSS and known as TSLS. Different strain than the pharyngitis strain. Produce lots of exotoxin A which is a superantigen. Superantigen is more closely related to Scarlet fever exotoxin but it has the same mechanism of action as the TSS toxin. Endotoxin (SpeA) enters blood causing fever, rash, shock, and 30% death

Front 28

Streptococcal Pyogenes Disease 2

Back 28

3) Necrotizing fasciitis - Caused by a severe Group A infection. Leads to muscle and fat destruction along the fascial planes. It is introduced by a break in the skin, and it is known as a "flesh-eating bacteria". Mortality is very high
4) Rheumatic Fever - Strep throat can be followed by rheumatic fever (a delayed sequela of strep pharyngitis) It is caused by specific strains of M-serotype group A streptococci. The symtoms are polyarthritis, carditis, or both. You can also get a neurological disorder, Sydennnham's chorea, subcutaneous nodules, or erythema marginatum. These can all be resolved except carditis
-Carditis leads to heart failure, or more commonly patients have valvular scarring leading to a impaired heart and bacteria infection.
-Leading cause is cellular immunity in which Strep antigens evoke cross-reactive T-cells. In other words, M-protein gragments stimulate cytotoxic T-cells to react against other cells like cardiac myocytes.
-Autoimmunity also causes kidney damage, nephritis
-Can be prevented by treating pharyngitis with penicillin, however, once you have Rheumatic fever it is nonresponsive.
5) Skin Infection
a) Impetigo - occurs in epidermis
b) Erysipelas - occur in dermis
c) Cellulitis - occur in SubQ where necrotizing fascitiis occurs

Front 29

Streptococci Group A Virulence Factors

Back 29

1) M-protein is the best defined
-Fibrillar molecule with C-terminus in PG wall and N-terminus at the surface
-It is absolutely essential for Strep virulence because it binds serum beta-globulin factor H. Once bound, factor H degrades opsonization factor C3b. Without C3b opsonization does not occur and pathogen can survive. This makes M-protein anti-phagocytic
-The N-terminus is constantly changing which leads to antigenic diversity. Even though a antibody can be made, no memory exists because of the changes
2) M-like proteins - Binds IgM and IgG
3) F-protein - adhesion
4) Pyrogenic exotoxin A - TSLS
5) Streptolysin - lyses leukocytes
6) Hyaluronidase - breaks down tissue so bacteria spread quickly

Front 30

Streptococcus pneumoniae

Back 30

-causes bacterial pneumonia, middle ear infection (otitis media) and bacteria meningitis
Morp: Gram-positive coccus, or diplococcus because it grows in pairs. It is an alpha-hemolysis molecule
Bile: Produces autolysin which degrades PG. Bile happens to activate autolysin. Thus, if S. pneumoniae is given bile it lyses itself rapidly
Other Structures: S. pneumoniae have a thick polysaccharide capsule. Each serotype has a distinct capsule composition. If you mix this bacteria with a antibody the capsule will swell

Front 31

S. pneumoniae virulence

Back 31

1) Adherence/Colonization - Exclusely a human problem. Spread between people by aerosols. Colonization in the nasopharynx occurs through an adhesion molecule that binds N-acetylhexosamine-glycolipid.
-The bacteria also makes sLgA protease which helps the bacteria avoid mucus trapping
2) After colonization S. pneumoniae passes the upper airway to the lungs. Pneumolysin plays a role in this
3) In the lung the bacteria avoid alveolar macrophages by using their antiphagocytic capsule so they are not engulfed. Also covers C3b or binds protein H to target C3b

Front 32

S. pneumoniae virulence 2

Back 32

4) Inflammatory Response - Once in the lungs the bacteria's cell wall provoke inflammation leading to fever and lung damage. The bacteria activates complement and increase IL-1 and TNF-a production whcih do the tissue damage
5) Blood-Brain Barrier - Once in the blood stream the bacteria passes the barrier to enter cerebrospinal fluid and cause meningitis
-It causes a inflammatory disease at the blood-brain barrier endothelial cells which damage these cells so that they are leaky. Once leaky the bacteria is able to penetrate it

Front 33

Streptococcal Viridans

Back 33

-once plauqe is visible on the teeth bacteria like S. mutans can cause caries and periodontal disease

Front 34

Streptococcal Infection

Back 34

-generally sensitive to penicillin
-If you have a penicillin allergy you can use erythromycin or cephalosporin

Front 35

GI Infection Overview

Back 35

-most common type of infection
-cause diarrhea which is the biggest cause of death in 3rd world countries
-caused by gram negative rods
-symptoms include diarrhea (watery and bloody), dysphagia, ulcers, and fever

Front 36

Common Bacterial Agents of GI Problems

Back 36

-family of gram negative bacteria called enterobacteriaceae
1) E. Coli - most are avirulent and part of the normal flora.
-Serotypes classified on LPS O-antigen and flagella H-antigen
-5 different virotypes
a) Enterotoxigenic (ETEC) - most important. Cause diarrhea in infants and travelers small intestine. Has 2 plasmid encoded enterotoxin: heat-labile LT and heat stable ST
2) Enteroaggregative (EAggEC) - Use plasma-mediated adherence to cause diarrhea in SI
3) Enteropathogenic (EPEC) - Use plasma mediated adherence and cell destructive techniques in SI to cause diarrhea, fever, nausea, and vomiting
4) Enterohemorrhagic (EHEC) - Bacteria mediated Shige-like toxin in LI that cause bloody stool
5) Enteroinvasive (EIEC) - Plasma-mediated invasins that destroy epithelial cells in LI leading to watery diarrhea and dysentery. Can cause bloody diarrhea too

Front 37

Common Bacterial Agents 2

Back 37

2) Shigella - Causes dysentery where diarrhea has blood. High infectious with a low ID. Found in daycares and homosexuals
3) Salmonella - Closely related to E. Coli but a primary pathogen. In the normal flora of farm animals and a indicator of food/water safety. S. typhi cause typhoid fever
4) V. Cholerae - Cause cholera and acquired by drinking water contaminated with feces or by eating bad food. It is a motile, G-, rod with a single polar flagellum. In the SI it attaches to cells and produces a cholera endotoxin that causes diarrhea and electrolyte imbalance

Front 38

Virulence Factory for Watery Diarrhea

Back 38

-you get watery stool when bacteria colonize GI tract and produce toxins. These toxins lead to loss of electrolytes and fluids
1) Adherence and Colonization - E. Coli ETEC produces type 1 pili and pili called colonization factor I and II. CF only in pathogenic E. Coli and allow cell adherence so toxins can be secreted. Cholera has pili and Tcp for adherence
2) Toxins Related to Symptoms - Symptoms of E. Coli ETEC and V. cholera (watery stool) caused by secreted exotoxin. These are LT/ST in ETEC and cholera toxin (CT) in cholera (resembles LT).
1) CT/LT made of 5 B-subunits and an A subunit. The B-subunit helps adherence to host and entrance into the cell. The A-subunit acts as the ADP-ribosylating enzymes
2) A-subunit ribosylated G-protein a-subunit causing it to permanently activate adenylate cyclase
3) Tons of cAMP are made which activates PKC which phosphorylates proteins which allow for ions and water to leave the cell
-Cholera allows for much more fluid to be released

Front 39

Virulence Factor for Bloody Diarrhea

Back 39

Example is Shigella and EHEC
Adherence, Invasion, Spread:
1) Plasma-encoded invasins (ipa A-D). Bind to host integrin so bacteria taken up by cell
2) Bacteria disrupt vesicle for release into the cytoplasm. In cytoplasm they multiple and spread to other nearby cells
3) Proteins called ics allow bacteria to spread to neighboring cells. This kills mucosal cells and leads to inflammation

Toxins:
1) Shigella and EHEC produce A-B exotoxins. B-subunit recognize host cell to allow for endocytosis
2) A-subunit inactivates the host ribosome by cleaving 28S rRNA which blocks protein synthesis leading to cell death
...EHEC virulence comes from a bacteriophage which has the exotoxin

Front 40

Salmonella Infection

Back 40

-true pathogen
-obtain by ingestion of food or fecal-oral spread
-3 types of infection caused by difference strains
1) Enteritis - most common. Lead to vomitting and diarrhea for a few days
2) Typhoid Fever - After week incubation patients get a bad fever which can be fatal. In typhoid fever the bacteria has invaded the bloodstream and lymph node and is dividing in the liver and spleen
3) Asymptomatic carriage - Some people with Salmonella show no symptoms but remain carrier
-usually Salmonella hides in the gallbladder and is released to the liver

Front 41

Salmonella Adherence and Invasion

Back 41

1) Invade host by triggering actin rearrangement that leads to pseudopods which engulf the bacteria. Invade the cell with inv A-H gene which allows for adhesion
2) Bacteria multiples itself in the vesicle until the epithelial cell burst
-It is able to survive the endosome conditions using acid tolerance response (ATR) gene. This gene protects Salmonella from the pH of the stomach and endosome

Front 42

GI Bacteria Treatment and Prevention

Back 42

1) Because most symptoms go away antibiotic is not recommended
2) Best cure is to restore food and correct metabolism imbalance
3) For complicated cases antibiotics are sometimes given, like in typhoid fever. In other cases the jury is still out
-Problem is that some work shows that antibiotic treatment can make the symptoms worse by inducing the temperate phage with SLT gene to enter lytic cycle
4) Vaccines against typhoid fever are available

Front 43

Gonorrhea

Back 43

-caused by Neisseria gonorrhoeae
-gram-negative cocci in transparent colonies
-N. gonorrhoeae causes gonorrhea and N. meningitidis cause septicemia and meningitis
-To culture they require carbon dioxide, boiled blood, iron and vitamins. Therefore, transmitted by sexual contact cause fragile outside body
EPI: only infect humans. Women have a higher risk of infection than men. Many people are asymptomatic
Clinical Syndromes:
1) Men - Urethral discharge and dysuria after 2-5 days
2) Women - In cervix they get vaginal discharge, dysuria, and ab pain. Also get cervicitis which appears as no symptoms. Cervicitis can lead to pregnancy problems (scar fallopian tube), arthritis (knees), and pelvic pain.
-Disease can be passed to infant in birth passage in the eyes and cause blindness. Infant gonorrhea is called ophthalmium neonatorum. Argyrol is a silver based drug used to prevent newborn eye problems associated with Gonorrhea
-no vaccine available

Front 44

Pathogenesis and Virulence

Back 44

1) Adherence and Invasion - Attach to mucosal cells, penetrate and multiply in cell.
a) Use pili for initial attachment
b) Membrane protein P.II helps with a tigher association and migration into bacteria
c) Out membrane protein P.I helps impair phagocytic death in epithelial cell or leukocyte. Does this by reducing the oxidative burst or preventing phagolysosome fusion

Front 45

Antigenic and Phase Variation

Back 45

-Even though pili and surface proteins are immunogenic (seen by immune system), they have strategies to avoid a immune response
1) Antigenic Variation - Pili gene pilin undergoes constant change throughout course of single bacterium. Hard to use antibodies against that recognize antigen. Similar to a B-cell, each time it multiplies a new pili combination is used
2) Phase Variation - Can turn surface components on or off to avoid detection
3) IgA Protease - Gonorrhea makes this enzyme which inactivate antibodies produced at mucosal surface
4) LPS endotoxin - Gonococcal makes a LPS similar compound called lipooligosaccharide (LOS). LOS trigger an inflammatory response which is primary responsible for the damage caused by gonorrhea. TNFa is believed to cause main damage to fallopian tubes. LOS also prevent antibodies access to surface antigens

Front 46

Gonorrhea Treatment and Prevention

Back 46

-curable and cheap
-since gonococci have a plasmid with B-lactamase, you can use a B-lactamase-resistant cephalosporin or ceftriaxone
-early diagnosis, partner notifcation, condom use, and less sex all help too

Front 47

Syphilis

Back 47

-sexually transmitted disease
ETI: caused by Treponema pallidum. A thin Gram-negative spirochete that never forms colonies. Strict human pathogen which cannot be grown in cell-free culture. Must be visualized by darkfield illumination or staining. Cannot survive outside the body
EPI: Disease raged Europe in 1500s but has decreased since penicillin advent. Most common routes of infection are sex and blood

Front 48

Syphilis Clinical Syndromes

Back 48

3 stages
1) Primary Stage - Develop a chancre at the site of inoculation. Chancre disappears spontaneously and this can be the end sometimes. It is very contageous at this point
2) Secondary stage can develop if the bacteria penetrates the mucosal membrane and enters the blood-stream.
-symptoms are fever, rash, lymphadenopathy
-very contageous
-symptoms can heal spontaneous and the disease enters a latent stage. From the latent stage a small proportion can relapse back to secondary syphilis. A small proportion can also develop into tertiary syphilis
3) Tertiary - Bacteria leave blood and invade several organsd like heart, muscle, and brain. Although not infectious this can cause mortality

Congenital Syphilis - Babies can be born with this disease. This can lead to premature birth, retardation, and organ failure. Later in life is can lead to facial and tooth deformities. Women positive can be given penicillin

Front 49

Pathogeneis and Treatment of Syphilis

Back 49

Pathogenesis: Hard to study cause bacteria never cultivated in lab medium. It appears that the protein antigens are not exposed on the bacteria surface so antibodies cannot find them. Also, it seems like tertiary syphilis uses the immune system to play a deleterious role

Treatment: Can use penicillin. If allergic you can use tetracycline or doxycycline
-Benzathine penicillin for early syphilis and penicillin G for late or congenital sphilis

Front 50

Chlamydia

Back 50

-most common sexually transmitted disease
-cause by Chlamydiae trachomatis
-obligate intracellular pathogen, it is tiny .3um. Due to size it has a tiny genome and cannot make ATP so uses the host
EPI: Trachomatis cause genital tract infections, lymphogranuloma (LGV) and trachoma
-trachoma is a eye infection that can lead to blindness

Front 51

Chlamydia Clinical Syndromes

Back 51

-because of the mild symptoms it is usually not recognized and can spread easily
1) Genital Infection - leads to mild urethritis or cervicitis with little pain. Cervicitis can ascend the upper genital tract leading to tube scarring, ectopic pregnancy, and infertility
2) LGV - Cause severe genital tract infection leading to abscesses of lymph nodes
3) Trachoma - Major cause of blindness in developing countries. Can be passed through inanimate object, aerosol, clothing, or contaminated feces. Leads to eye infection (serovar strain) with conjunctivitis. This causes the patient's eyelashes to turn inward which abrade the cornea leading to loss of vision

Front 52

Chlamydia life cycle

Back 52

-exist in 2 morphological forms
1) Elementary Body - small, strong, infectious, but not metabolically active so it cannot replicate
2) Reticulate Body - Larger, metabolically and replicating. Osmotically fragile and must live inside host

Life Cycle:
1)EB become attached to cells
2) EB penetrate the host cell and remain in the phagosome
3) 6-8 hours later they reorganize into RB and replicate themselves
4) 18-24 hours after infection they turn from RB to EB as the cell ruptures

Front 53

Treatment

Back 53

1) If patient has ocular or genital infection you can use azithromycin or doxycycline
2) For pregnant women and children you must use erythromycin or sulfisoxazole instead of doxycycline
3) Doxycycline is great for LGV
4) Use safe sex and prompt treatment

Front 54

Oral Microbiology Intro - Terms

Back 54

HIstory: Leeuwenhoek was both father of microbiology and oral microbiology. He first looked at dental plaque, calling it anialcules

Stains: Pigmented (color) deposits found on or within the teeth. 2 major types
1) Intrinsic - Example is tetracycline. Mom takes this during pregnancy and the Tet sticks to tooth Ca++
2) Extrinsic - Can be caused by chlorhexidine mouthwash. Kills bacteria which then release their pigment on the tooth surface. Can also be caused by coffee drinkers and heavy smokers

3) Materia Alba - A random accumulation of host cells, food particles, and bacteria. It is loosely attached to the teeth and easily removed with air-water syringe

Front 55

Oral Microbiology Intro - Terms II

Back 55

4) Dental Plaque - A highly structured accumulation of bacteria and their extracellular products. Since it is tightly attached to the surface it can only be removed mechanically. It is not pathogenic by itself, but it can attract other bacteria which are pathogenic

5) Calculus (Tartar) - Calcified dental plaque which is covered by a layer of normal plaque. Forms supergingivaly and comes in all types of colors, even white.

-the amounts, location, and color of plaque and calculus varies between people. Even within the same tooth, the composition of calculus between surfaces can be different
-microbial deposits will form on just about anything in the mouth, real or prosthetic. Must remind patients to clean all parts of the oral cavity

Front 56

Dental Plaque

Back 56

-microbial deposits that form on teeth, soft tissue, and restorations
-composed of bacteria and their products. Can sometimes include salivary molecules
-high organized and forms through a structured process
-the microbe composition can vary between people, teeth, and tooth surfaces
-The pathogenicity of plaque varies. Some is harmless, other causes caries and/or periodontal disease
-plaque is considered a bacterial biofilm
-having patients control plaque is a huge part of dentistry

Front 57

Bacterial Biofilms

Back 57

-bacteria can live in a biofilm or a planktonic state
-a biofilm is bacteria attached to each other and/or a substrate and surrounded by matrix. Biofilm protects bacteria from antibiotics and allows new bacteria to "hide" and relocate via planktonic saliva
-a planktonic state is bacteria suspended in fluid

Biolfilm
1) Composed of ecologicaly "micro" communities
2) Many microenvironments exist within each biofilm. These differ by pH, temperature, oxygen, e- potentials
3) Have primitive circulatory systems
4) Metabolic outputs can be cooperative or antagonistic towards their neighbors
5) Bacteria in biofilm are relatively resistant to typical host defense mechanisms
-constant immune exposure does not get rid of plaque. May be due to gene expression, proteases could degrade immunoglobins. Could be because they are physically bound and immune cells cannot get access
6) Resistant to systemically and locally delivered antimicrobial agents
-bacteria in biofilm are resistant to host cells and antimicrobial agents

Front 58

Steps in Biofilm Formation

Back 58

1) Attachment

2) Growth

3) Deattachment

Front 59

Helicobacter Pylori and Gastric Ulcers

Back 59

-Gram negative rod that is spiral shaped and can tunnel through mucus layer
-mainly affects adults
-causes gastritis (inflammation in stomach) and ulcers (sore on lining of stomach or duodenum)
-cause abdominal discomfort after a meal or middle of the night. Relieved by eating and antacids
-can progress from gastritis to intestinal cancer

Front 60

Helicobacter Pylori Clinical Manifestations and Virulence

Back 60

1) colonize in antrum of stomach
2) Use flagella and spiral shape to drill through mucus layer
3) Uses adhesins to bind membrane lipids and carbs
4) Destroys gastric mucosa and epithelial cells, inflammation occurs, and ulcer/gastritis form

Virulence
1) Urease - Converts urea to ammonia and bicarbonate. The ammonia neutralizes the stomach pH but it is toxic to gastric epithelial cells leading to vaculoation
2) LPS and Cytotoxins - LPS inhibits mucus glycosylation so it goes from high to low molecular weight. At low molecular weight the surface epithelial cells have weakened protection and are vulnerable to acids. Helicobacter pylori also has special lipid A that reduces immunologic activity

Front 61

Marshall and Warren

Back 61

-saw a connection between % of people at a certain age with H. pylori antibodies, and the % of people with gastritis
-Barry tested his theory on himself and drank a solution of H. pylori and gastritis occurred. Getting rid of the bacteria got ride of the gastritis

Front 62

H. Pylori Diagnosis

Back 62

Invasive:
-use a endoscope and biopsy
-do a biopsy urease test
-do a biopsy giemsa stain, a serological test looking for surface protein
Noninvasive:
-urease breath test using carbon labeled urea. Measure CO2 release with beta counter
-Use ELISA to test for antibodies in serum or saliva

Front 63

H. Pylori Treatment

Back 63

Triple Therapy
1) Prevacid - reduce acid for quick relief. Use lansoprazole, a inhibitor of gastric acid secretion
2/3 - Antibiotic amoxicillin and clarithromycin

Front 64

Borrelia Burgdorferi - Lyme Disease

Back 64

-emerging disease since the 70s
-spirochete, need dark-field microscope
-use axial filament endoflagella in periplasmic space to move in cork-screw. Able to hide this antigenic adaptation from host immune system
-Carried by ticks, differ in states. In northeast 50% of deer ticks carry infection, in west only 2% of western black-legged ticks carry it

Front 65

Borrelia Burgdorferi Discover

Back 65

-Seen in Lyme, CN in 70s when large outbreak of juvenile rheumatoid arthritis
-In 82 Dr. Burgdorfer isolated this bacteria in the belly of ticks and showed a reaction between them and serum of infected individuals

Front 66

Symptoms of Lyme Disease

Back 66

1) Early Infection - Red rash at site of bite called a erythema migran with spirochete at the edge. Eventually develops into a bull's eye
2) DIssemination Stage - Spirochete spread to other body tissue leading to many symptoms like fever, headache, fatigue, joint pain
3) Persistent Infection - Intermittent episodes of joint pain and possibly meningitis, bell's palsy, cardiac trouble, and arthritis leading to cartilage/bone erosion

Front 67

Lyme DIsease Diagnosis/Treatment

Back 67

1) In early stages use a serodiagnosis to see anti-borrelia antibodies. This utilizes flow cytometry and is called Gundersen Lyme Test (GLT)
2) ELISA and indirect immunofluorescent assay (IFA)

Treatment:
1) Antibodies like doxycycline
2) LYMErixTM vaccine if at risk - outer surface protein A (OSP-A) of BB

Front 68

Mycobacteria and Tuberculosis

Back 68

Mycobacterium Tuberculosis is a acid-fast bacteria that is stained by a detergent and retains stain even with HCL acid. It grows slowly in cords, only in Lowenstein-Jensen media
-Surrounded by wax called mycolic acid
-Epidemic in 19th century until screening test (skin test, chest X-ray). Coming back due to AIDS patients
-Contracted through inhalation

Front 69

Tuberculosis Disease

Back 69

1) Primary - tubercle bacilli are ingested by alveolar macrophages and multiple inside here. Migrate to lymphatics (Ghon complex) with macrophage and create a immune response with inflammation in many places. At this point the skin test positive and X-ray shows dense patch in lungs (at this point still 95% heal themselves and never know they had it)
-Body forms a tubercle (granuloma) around the bacteria with epithelial cells, giant cells, and lymphocytes. This can heal but be reactivated in immunocompromised people
2) Secondary Tuberculosis - Due to impaired immune function you can get liquid lesion and necrotic symptoms in the upper lungs with bloody sputa and hemorrhage

Front 70

Virulence

Back 70

-do not produce toxins, all due to inflammatory response
1) Unusual Cell Wall - Has arabinogalactanlipid (glycolipid) and mycolic acid (wax). Protects bacteria from phagolysosome and drying out
2) Survival In Macrophage - Survive in replicate in macrophage using
a) Inhibit fusion or escape into membrane-bound vesicles
b) Get into cytoplasm
c) Replicate in fused phagolysosome - prevent digestion using oxygen scavengers PGL-1 and LAM, enzymes catalase/SOD, and HSP elements
3) Avoidance of Activated Macrophage Response - Cell wall blocks activation of macrophage by interfering with released cytokines
4) Tissue Distrubtion - Damage host tissue by eliciting a inflammatory response. Major damagers are TNF alpha and

Front 71

Diagnosis

Back 71

1) Skin Test - Inject tubercle protein mixture called purified protein derivative (PPD). Look for positive reaction indicating cellular immunity by red ring greater bump > 10mm
2) Chest X-Ray - Look for dense lesion in lung. Picks up granuloma or ghon
3) Microscopic - Acid-fast stain of sputum. Not specific for just tuberculosis and can be false negative if numbers low. Also, takes a while to do this test due to slow growth

Front 72

Treatment/Prevention

Back 72

Multiple drugs for long term therapy
6-9 months of chemotherapy
INH and rifampin for 6 months, and pyrazinamide additionally for 2 months
-sanitation helps
-vaccine called BCG (bovine) made by tuberculosis that lost its virulence

Front 73

Virulence Factor: Adherence and Colonization

Back 73

-attachment very important in places washed by fluid (GI tract, mouth, bladder)
1) Pili - Long tube made of pilin (pilus) and tip made of proteins that bind carbs and mediate specificity (tip adhesion complex)
2) Afimbrial adhesin - Tighter binding than pili. Example is gonorrhea P.II. Circular and bind protein or carb. Bind after pili normal attachment. P.I prevents phagolyosome fusion
3) E. Coli Pili -
a) ETEC has CFA Known as colonization factor, required for virulence. CFA I and II. Also has Type I Pili
b) Also has regular avirulent pili (common pili) that binds mannose-lipin
c) Uro E. Coli binds urinary tract using P. Pili which binds galactose. Blood type with this galactose is P+
4) Pertussis - Uses filamentous hemagluttinin Fha which binds cilia via galactose containing protein

Front 74

Virulence Factor: Invasion of Host Cells and TIssues

Back 74

-bacteria that live in or out of host (salmonella, shigella, and tuberculosis) have adhesins called invasins. Need to get in and survive inside to make it
Gain Access Via Nonphagocytic
1) Internalization via ligand/receptor affinity. Examples is EHEC/Shigella that use ipa A-D with integrins to be brought in. Called "Zipper". The bacteria Yersinia also does this
2) Signaling and modulating host cytoskeleton components. Example is salmonella INV A-H which triggers actin rearrangement and brought in pseudopods. Called "Trigger"
Gain Entry to Phagocytic Cell
M. Tuberculosis - endosome using protein that disrupt membrane by degradating or forming pores

Front 75

Virulence Factor: Avoidance of Host Defense Mechanism - Inhibit Complement

Back 75

1) Inhibit Complement Cytolysis or Opsonization
a) Masking surface components - Done by S. aureus through its capsule.
b) Coat themselves with IgA because it is complement neutral. N. meningococci does this
c) S. pyogenes produces a C5a peptidase that cleaves this part of complement
d) Salmonella and E. Coli produce long LPS that don't allow complement membrane attack complex (C5-C9) from latching on

Front 76

Antiphagocytic Activity

Back 76

1) Use capsules like S. pneumonia
2) Lyse phagocytic cells like S. pyogenes streptolysin
3) Staph and Strept make protein A which binds IgG by Fc end to prevent opsonization
4) S. pyogenes make M-protein which binds Factor H which degrades C3b so no opsonization. Cb3 receptor on pathogen binds C3b on phagocyte for take it

Front 77

Virulence Factor Continued

Back 77

1) Antigen Variation- Gonorrhea can change antigen expression cause pili can be remade
2) Superantigens - Activate all T-cell clones in a non-specific manner. S. aureus TSST-1, staphylococcus enterotoxins, and exfoliative dermatitis toxin

Front 78

Bacterial Toxins Endotoxin

Back 78

-classified into exotoxin and endotoxin
Exotoxin - Produced by bacteria and secreted to environment
1) Block protein synthesis - Diptheria A-B (E2F) and Shigella/EHEC A-B that degrades 28S of ribosome
2) Hijack Normall Cell Function - Cholera CT has abnormal adenylate cyclase produce cAMP leading to protein activation and release of fluid and electrolytes.
3) Screw Host Defense - S. aureus TSST-1 acts as a superantigen
4) Some toxins are degradative like Necrotizing Fasciitis S. pyogenes hyalauronidase.

Front 79

Bacterial Toxin A-B

Back 79

1) Single polypeptide A-B covalently linked. Example is Diphtheria toxin DT

2) Multiprotein complex with A-B noncovalently linked. Example is CT and PTX that activate G-protein. CT has 5 B-subunits while PTX has 4 different B-subunits

3) A and B found on separate protein, don't form any bond like C. botulinum

ADP-Ribosylation
1) Diphtheria ribosylates E2F
2) CT and PTX ribosylate G-protein enabling adenylate cyclase activity
3) Shigella and EHEC block protein synthesis by destroying ribosome 28S
4) Some exotoxins form a pore/channel in the membrane to disrupt cell integrity

Front 80

Bacterial Endotoxins

Back 80

-are the lipopolysaccharides of G- bacteria which trigger inflammation
-Many times, even after bacterial death, LPS can trigger macrophage activation and release of cytokine inflammation
-LPS bind LPS binding protein, and together they bind m-phage CD14

Front 81

Tissue Damage from Immune Reaction

Back 81

-bacterial products trigger autoimmune response if the antigen resembles a host cell antigen. This happens with M-protein in rheymatic fever where myocytes are attacked
-Bacterial pathogen elicit inflammatory response - M. tuberculosis does this by eliciting TNFa. Also pus is the same