BIOL 207: Microbiology Final Content

WKU BIOL 207 content covered in the final

exotoxin

protein with STRONG specificity for target cell and VERY POWERFUL.

endotoxin

protein with SYSTEMIC effect, not specific. example is LPS

localized

an infection that is restricted to a specific area or tissue of the body, often causing localized symptoms.

systemic

relating to or affecting the entire body, rather than a specific area or organ.

focal

pertaining to a localized point or area within a larger system, often referring to infections that spread from one site to others.

acute

a condition with a rapid onset and a short duration, often characterized by severe symptoms that may require immediate attention.

zoonosis

an infectious disease that can be transmitted between animals and humans. Examples include rabies and West Nile virus.

nosocomial

relating to infections acquired in a healthcare setting, such as hospitals. most common one is UTI

first

this line of host defense is anatomical structure (physical barrier). very general

second

this line of host defense is general defense. (internal system of protective cell and fluid). includes INFLAMMATION and PHAGOCYTOSIS.

third

this line of host defense is acquired on an INDIVIDUAL BASIS as each substance is encountered. ma

marker

molecule on cell surface made of protein/sugar that immune system evaluates to identify threats.

bone marrow

site of RBC and WBC development/maturation

thymus

part of bone marrow where T lymphocytes mature

lymph

this fluid is derived from ECF. contains WBC, ECF, cellular debris, and infectious agents. NOT RBC

neutrophil

general purpose phagocytes. 40-60% of total WBC. react EARLY in INFLAMMATORY response. high count of this is sign of infection. primary component of PUS

monocyte

transform into macrophages after they migrate from bloodstream to tissues

macrophage

they eat pathogens. include alveolar (lung), kupffer cells (liver), dendritic cells (skin)

PAMP

pathogen associated molecular patterns. signal molecules on microbial surfaces. recognized by phagocytes. NOT HAD BY MAMMALS.

PRR

pattern recognition receptor. found on PHAGOCYTES. recognize and bind PAMPs.

inflammation

classic symptoms:

• RUBOR: redness

• CALOR: warmth

• TUMOR: swelling

• DOLOR: pain

function: mobilize immune components, destroy microbes

cytokine

small signaling molecule (soluble protein) secreted to regulate inflammation and immunity.

interferons

these cytokines inhibit virus replication

diapedesis

migration of WBC out of blood vessel into tissue.

lymphocyte

B and T cells. subset of leukocytes (WBC). main soldiers.

B cell

give antibody mediated immunity. produced and mature in bone marrow.

CLONAL EXPANSION: make antibody secreting plasma cells + memory B cells

T cell

produced in bone marrow, mature in thymus. cell-mediated immunity

helper T cell

these T cells secrete cytokines to control immune response

cytotoxic T cell

these T cells destroy foreign cells

candida

(yeast). colonizes oral mucosa

pharyngitis

(sore throat). inflammation of throat.

causative agent: strep pyogenes and common cold viruses

symptoms:

• red/swollen mucosa

• swollen tonsils

• foul breath

  • white packets visible in throat wall → strep throat

strep pyogenes

gram +

streptococci

capsule + slime layer

facultative anaerobe

cat -

reservoir: humans

transmission: respiratory droplet, direct contact, fomite

treatment: penicillin, since many GAS (group A strep) are resistant to erythromycin. cephalexin for patients with penicillin allergies

virulence factors:

• surface antigens:

  • lipotechoic acid

  • M protein

  • hyaluronic acid

• extracellular toxin

  • streptolysin

  • erythrogenic toxin → causes rash, fever. typical of scarlet feveer

diseases:

• scarlet fever (scarlatina): sandpaper like rash and high fever, school-age children

• rheumatic fever: damage to heart valves, arthritis in 2+ joints.

• glomeronephritis: formation of antigen-antibody complexes in kidney glomeruli.

• TSS (toxic shock syndrome)

• sore throat/pharyngitis → 30% of this caused by this

rhinitis

(common cold). caused by 200+ viruses.

transmission: indirect contact, droplet contact

symptoms:

• sneezing/runny nose

• scratchy throat

  • low fever in kids

sinusitis

inflammation of sinuses. caused by various stuff.

treatment: broad-spectrum antibiotics for bacterial infection, or antifungals, or surgerydi

diphtheria

caused by corynebacterium diphtheriae

non spore forming

gram +

club-shaped rod

transmission: droplet contact, direct contact, fomites

prevention: diphtheria toxoid vaccine (DTaP)

treatment: antitoxin + penicillin/erythromycin

culture/diagnosis: tellurite medium → black colonies

virulence factor:

• diphtheria exotoxin encoded by bacteriophage

symptoms:

• acute sore throat with pseudomembrane formation

• bull neck (lymphadenopathy)

influenza

causative agent: influenza A, B, C viruses, orthomyxoviridae (LPS envelope, glycoprotein spikes (H and N))

transmission: inhalation of virus-laden aerosols, indirect contact with fomites, crowding, poor ventilation, drier air of winter. affects very young and very old

prevention:

• inactivated seasonal vaccine → 70-90% effective. anyone over 6 months

• live attenuated seasonal vaccine → stimulates secretory immunity

symptoms:

• starts in upper respiratory tract, can progress to lower tract

• headache

• chills

• dry cough

• body aches

• fever

• stuffy nose

• sore throat

• extreme fatigue

• secondary infections

ANTIGENIC DRIFT: mutation of glycoprotein (H, N) genes. small scale change in viral genome. causes most seasonal flu strains

ANTIGENIC SHIFT: RNA exchange between viruses. large scale genome change. occurs during coinfection. most likely to make pandemic strains (H1N1, H5N1)

virus binds to ciliated cells of respiratory mucosa

cytokine storm

an extreme, uncontrolled immune response where the body releases too many inflammatory proteins (cytokines), overwhelming the system

tuberculosis

AKA white plague

causative agent: mycobacterium tuberculosis

acid-fast bacillus

strict aerobe

slow growing

resistant to drying/disinfectants

transmission: POVERTY. droplets of mucus on air. can survive 8 months in aerosols.

culture/diagnosis: tuberculin testing, chest Xray, direct ID of AFB

• tuberculin testing (Mantoux Test): PPD injection given intradermally into forearm. observe site for size of red wheal after 48 hours. limited to people with higher TB risk

  • positive → recent infection or reactivation of prior latent infection

  • false positive from vaccinated people

  • false negative from immunocompromised people

• acid fast staining (Ziehl-Neelsen stain). AFB is bright-red

prevention: limit exposure to infectious airborne particles.

• issues of antibiotic resistance:

  • MDR-TB (multidrug resistant TB): affects immunocompromised patients (HIV)

    • XDR-TB (extensively drug resistant TB): resistant. 2nd line of anti TB drugs. worldwide.

symptoms:

• humans easily infected but resistant to disease development

• 85% of TB cases contained in lungs

• 3 forms: primary, secondary, extrapulmonary

diseases:

• primary TB: min ID is ~10 cells.

  • multiply inside macrophages of lung. escape from macrophages leads to cell-mediated attack.

  • TUBERCLE: lung caseous lesion that heals with calcification

• secondary TB: live bacteria stay dormant, then reactivate

  • chronic TB: tubercles expand

  • consumption (development of severe symptoms)

• extrapulmonary TB: infection outside lungs. can be in lymph nodes, kidneys, genital tract. found in immunosuppressed patients and young children.

pneumonia

inflammation leads to fluid filled alveoli.

causative agent: viruses, bacteria, fungi

pathogens must avoid being eaten by alveolar macrophages

transmission: immunocompromised patients. normal biota enter lower tract via abnormal breathing, aspiration, ventilation

culture: usually shows normal biota only

treatment: empiric therapy with broad-spectrum antibiotics

diseases:

• CAP (community acquired pneumonia): people in general population

  • caused by:

    • bacteria: strep pneumoniae (2/3 of CAP), legionella sp. (less common), mycoplasma pneumonia (walking pneumonia)

    • viruses (hantavirus, SARS, adenovirus)

    • fungi

• pneumococcal pneumonia: alpha hemolytic, most common.

  • virulence factor: capsule

  • vaccine: Pneumovax for older adults

• atypical pneumonia (mycoplasma): lack of acuteness.

• nosocomial pneumonia → 1% of hospitalized people. 2nd most common nosocomial infection. polymicrobial infection:

  • klebsiella pneumonia

  • strep pneumoniae

  • anaerobic/coliform bacteria

food poisoning

toxin-mediated disease from food.

fish, shellfish, or mushrooms

violent symptoms

short incubation period

condition known as intoxication

caused by:

• staph aureus

  • staph aureus exotoxin: custard, sauce, cream pastry, meat, chicken salad, ham.

    • doesnt alter food taste/smell.

    • heat stable: heating food wont stop it

• bacillus cereus

• Clostridium perfringens (gram +, sporulating)

  • also causes gas gangrene

  • c perfringens exotoxin: endospores contaminate meat/fish, germinate when it cools

salmonella

high infectious dose (ID_50).

causative agent: salmonella enterica. many subtypes

reservoir: poultry/eggs

prevention: avoid contaminated products

treatment: fluid/electrolyte replacement. antibiotic treatment for severe cases

e coli O157:H7

most virulent e coli strain (EHEC/STEC).

range from mild gastroenteritis with fever to bloody diarrhea

some patients develop HUS (hemolytic uremic syndrome) → type of anemia causing kidney damage and/or death

makes SHIGA TOXIN

reservoir: contaminated/undercooked beef/veggies → farms

prevention: dont eat rare/raw hamburger/wash veggies

common epidemics

c diff

Clostridioides difficile. normal, opportunistic microbiota. can be fatal

disease:

• pseudomembranous colitis

common in hospitals: community-acquired outbreaks after treatment with broad-spectrum antibiotics

treatment: withdrawal of antibiotic. FMT (fecal microbiota transplant)

rotavirus

double stranded RNA virus. seasonal.

main cause of morbidity/mortality from diarrhea. (50%)

transmission: oral-fecal route. children at risk.

treatment: fluid replacement/electrolytes

shigella

gram -

nonmotile rod

makes SHIGA TOXIN

prevention: good hygiene, avoiding contact

treatment: split consensus for antibiotic use or not

symptoms:

• shigellosis

• frequent watery stools

• fever

• intense abdominal pain

• nausea

• vomiting

• dysentery: stools with blood/mucus from GI tract

shiga toxin

enterotoxin (gut) by shigella and e coli O157:H7. affects GI tract, damages mucosa and villi, mostly in large intestine

causes high fever, HUS

fecal-oral route

preschoolers at risk

helicobacter pylori

curved, motile, gram - rod

2005 nobel prize: first isolation by Warren and Barry Marshal

transmission: unknown. fecal-oral route suspected. present in large part of population as normal biota.

diseases:

• gastritis: sharp burning pain from abdomen

• gastric ulcer: lesions in stomach mucosa or upper small intestine (ileum). AKA peptic ulcer. bloody stool, vomit, etc

virulence:

• pass into GI tract

• bore through outer mucus layer lining

• attach to cell binding site

• causes ulcer by avoiding stomach acidity by making urease enzyme to break urea → ammonia (bad breath).

• causes large sores, acute pain

• chronic inflammation → stomach cancer

hepatitis

liver condition. (inflammatory disease (necrosis of hepatocytes) and mononuclear response that swells liver).

interfere with bile excretion of bilirubin into intestine

JAUNDICE: yellow skin tinge and eye tinge caused by bilirubin accumulation in blood/tissue

causative agent:

• viruses: EBV, hepatitis viruses A-E

• noninfectious condition: autoimmune disease, drug/alcohol abuse

disease:

• HAV/HEV: single stranded nonenveloped RNA virus.

  • fecal-oral route

  • minor, self-limited hepatitis

  • HEV → pregnant women, 15-25% fatality

  • HAV AKA infectious hepatitis

    • symptoms:

      • initial: anorexia, vomit, low fever

      • liver enlarges: jaundice (dark urine), lasts several weeks

    • diagnosis: liver function tests presence of antibodies

    • recovery gives lifelong immunity

• HBV (serum hepatitis) → hepadnavirus (nucleocapsid with DNA):

  • serious/fatal

  • coinfection with HDV (delta agent)

  • types:

    • HBsAg (surface antigens): spheres/rods of surface proteins

    • complete virion (Dane particles): HBsAg (surface) + HBcAg (core)

  • diagnosis: presence of HBsAg

  • transmission: body fluid contact, nonsterile needles

  • symptoms:

    • initial: similar to HAV

    • severe illness, longer jaundice, most people clear HBV. most stay carrier, others get chronic infection

  • complications:

    • cirrhosis: irreversible liver scarring

    • hepatocellular carcinoma (HCC): liver cancer

  • treatment: interferon therapy, base analog

  • vaccine: recombivav HB. for all ages. required for healthcare workers

• HCV → RNA flavivirus. common in drug users, tattos, body piercings

  • SILENT epidemic: no vaccines, asymptomatic → high risk of spread

  • symptoms: initially asymptomatic. cirrhosis/HCC can occur

  • common cause of liver transplants

syphilis

3 stages if left untreated.

causative agent: treponema pallidum (pale spirochaete), no cell wall, moves with axial filanets (endoflagella), obligate parasite, slow generation time (30h)

transmission: human host only. must spread via sex. penetrates skin via mucous membranes/wound/abrasion. 3 week incubation

treatment: antibiotics → penicillin.

diseases:

• primary syphilis:

  • CHANCRE: painless circular purplish ulcer with raised margin full of spirochaetes → often on genitals

  • stays for 2-3 weeks

• secondary syphilis:

  • fever and flu-like illness

  • swollen lymph

  • skin rash mistaken for measles/chickenpox

  • loss of hair

  • liver affected

  • most patients recover and remain pockmarked → latent stage

• tertiary syphilis:

  • GUMMA: soft, painless gummy, granular lesion: affect all vitals → symptoms of severe insanity and finally death

  • affects skin

  • cardio system

  • nervous system

  • lasts for 6-40 years

• congenital syphilis: spreads from mother to fetus

  • HUTCHINSON’s TRIAD: classic combo of symptoms of infected children

    • deafness

    • impaired vision

    • peg-shaped teeth (hutchinson’s teeth)

gonorrhea

infection of urogenital tract

2nd most reported microbial disease in USA

causative agent: neisseria gonorrhoeae (small gram - diplococcus (gonococcus)). kidney-bean shaped with flat sides touching.

very fragile → susceptible to common disinfectants

transmission: person to person contact. incubation period 2-6 days

control/cure:

• prevention over cue

• penicillin USED to be effective → developed resistance

• now, tetracycline + drug therapy

• no vaccine

symptoms:

• females:

  • bacteria invade epithelial surfaces of cervix and urethra

  • cervix reddened → abdominal pain/burning when peeing

  • complications:

    • salpingitis: inflammation of fallopian tubes

    • PID (pelvic inflammatory disease); salpingitis that includes inflammation of other parts of upper reproductive tract.

      • become associated with anaerobic bacteria to cause a mixed infection

      • buildup of scar tissue can block fallopian tubes, causing sterility and ectopic pregnancy

      • this is less common as a cause of PID under chlamydia

• males:

  • invades mucous membranes of urethra

  • pain in urination

  • discharge of whitened thick fluid

  • frequent urination → groin lymph nodes are swollen

  • more acute symptoms in males → can cause sterility

diseases:

• gonococcal ophthalmia: blindness to infants from infected mother.

  • prevention: wash newborn eyes with 1% silver nitrate/antibiotic

• gonococcal pharyngitis: due to oral-genital contact

• gonococcal proctitis: due to anal

• keratitis: disease of eye cornea

chlamydia

inflammation of urethra along with discharge.

MOST frequently reported infectious disease in USA (mandatory reporting). affects young people (under 25) commonly.

causative agent: chlamydia trachomatis (genome sequenced in 1998)

AKA nongonococcal urethritis (NGV):

• 50% → chlamydial infection

• 25% → ureaplasmic urethritis

• 25% → other

transmission: sex. human host only. incubation period 1-3 weeks. 75% women and 50% men are asymptomatic and thus dont seek care.

control/cure:

• prevention over cure

• treated successfully with doxycycline/erythromycin

virulence: intracellular growth to avoid immune system.

diagnosis:

• fluorescent antibody test: swab as in a PAP smear

• immunoassay test

similar symptoms to gonorrhea:

• females: cervix inflammation/discharge. burning urination

  • complications:

    • spread to fallopian tubes, causing infertility

    • PID (MAIN CAUSE, rather than gonorrheae)

• males: painful urination/watery discharge

diseases:

• chlamydial ophthalmia/pneumonia: in newborns from infected mothers

  • silver nitrate not effective

  • erythromycin therapy recommended

• trachoma: adult condition. inflamed eyelid