Microbio Exam 3

Constant exposure to potential pathogens
Innate (tears, lysozyme) and specific (IgA defences)

Inflammation of conjunctiva membrane
Can be viral, bacterial, or due to allergy

Chickenpox
Shingles
Cold sores

Folliculitis, furuncle, carbuncle, scalded skin syndrome
Necrotizing fasciitis
Acne

Burns
Wounds
Gas gangrene

Common microflora, gram +, halophilic
Virulence factors: exotoxins (e.g. coagulase, exfoliation, enterotoxin)
Staphlylococcus aureus is most pathogenic species
Many drug resistant strains

hair follicle infection

deeper inflammation, pus, painful
1. Furuncle (boil): exterior layers inflamed
2. Carbuncle: multiple boils, deeper infection, fever

exfoliation exotoxin spreads in blood, destroys connections between skin layers (desmosomes), upper skin layer peels off

damaged mucosal membrane colonized
exotixin spreads from infection site, causing systemic inflammation
fever, rash, blood clotting, can lead to shock

commonly causes foodborne intoxications

clostridium perfringens (often)
strict anaerobe, endospores common in soil
germinates/thrives in dead (necrotic) tissue
virulence factors: invasive enzymes
fermentation products produce gas, odor, tissue destruction
quickly lethal without treatment, must remove dead tissue

'flesh-eating disease'
very invasive: express capsule, hyaluronidase, proteases, streptokinase, leukocidins, other virulence factors
destroys muscle/connective tissue
high mortality, damaged tissue must be removed

varicella-zoster virus (a herpes dsDNA virus, latent)
chickenpox endemic in US
respiratory entry, damages blood vessels, lyses skin cells, establishes latency in neurons
shingles (herpes zoster) occurs as virus reactivates, forms painful skin blisters
vaccine for both

present in 50-80% of adults in US, typically not STIs
often latent in trigeminal (facial) nerve

normal gut microbiome provides immune education, aides digestion, provides vitamins
problems (dysbiosis) can develop if altered

progression of chronic gum inflammation from gingivitis

viral disease primarily involving salivary glands
human reservoir only
aerosolized droplet transmission
attenuated vaccine

lytic RNA virus
commonly fecal-oral transmission
acute disease of liver, spleen
symptoms: fatigue, loss of appetite, jaundice from accumulation of bilirubin in tissues
normally self-limiting, not latent
effective vaccine

inflammation of the stomach and/or intestines
bacterial growth/invasion, bacterial toxins, or viral infection
causes vomiting and diarrhea

cause of most peptic ulcers
invades stomach mucosa, causes inflammation
chronic inflammation + stomach acid can erode mucosal stomach lining
treated with antibiotics

intoxication (usually caused by enterotoxin)
caused by poor food handling/storage practices

bacterial pathogen cause intestinal inflammation
longer incubation period than an anterotoxicosis
diarrhea, possible dysentery
enteric fevers more serious, can disseminate as sepsis
fecal-oral transmission
rehydration treatment

improperly prepared/stored meat, zoonotic via reptile
invades mucosa, causing inflammation of intestinal lining
fever (endotoxin), pain, nausea, bloody diarrhea
normally self-limiting (1-4 days)

commonly waterborne
higher virulence: enteric fever, invades mucosa, engulfed by macrophages which disseminate infection systemically
fever, headaches, sepsis

genus shigella
invade mucosal cells, then spread cell-to-cell
bloody diarrhea, cramps, fever
intestinal perforation and resulting peritonitis possible

most strains nonpathogenic
pathogenic strains: enterotoxigenic (ETEC) produce enterotoxin, enteroinvasive (EIEC) invade/kill mucosal cells, enterohemorrhagic (EHEC) produce potent toxin targeting specific organs

Associated with meat, milk, contaminated water, leading cause of bacterial enteritis
fever, abdominal pain, nausea, diarrhea

commonly cause diarrheal diseases, fecel-oral transmission
-rotaviruses present worldwide, vaccine exists
-norovirus common in US

non-specific: normal microflora, urine flow, enzyme/chemical barriers (lysozyme, low pH, salts in urine)
specific: neutralizing IgA

contain many functional untis called nephrons

more common in women
urethritis causes dysuria, can progress to cystitis
pyelonephritis results if infection 'ascends' to kidney
associated with incomplete/infrequent emptying of bladder, diabetes, hormonal changes
common hospital-acquired infection
chronic infections can result from bacteria invading/forming biofilm within bladder cells

follows disturbance of resident microflora, especially resident lactobacilli (rise in vaginal pH)
gardnerella vaginalis + anaerobc bacteria produce inflammation, itching, discharge
eukaryotic yest also common opportunist

genital warts (HPV)
gentital herpes
neonatal herpes

syphilis
gonorrhea
chlamydial infection
pelvic inflammatory disease (PID)

bacterial vaginosis

gram (-) diplococcus, highly infectious
virulence factors: attatchment pili, IgA protease, endotoxin, invades phagocytes
disseminated infections can cause serious infections in other organs/tissues
must treat partner, no vaccine, increasingly antibiotic resistant
common pathogens: neisseria gonorrhoeae

males: urethritis with pus within 1 week
females: more insidious, 80% asymptomatic, chronic inflammation can cause PID, sterility

main cause of nongonococcal urethritis (NGU), a non-neisseria urethritis transmitted as STI
most common bacterial STI, more often diagnosed in females
most infections (80%) are asymptomatic or mild symptoms
major cause of PID and infertility
can cause infections in newborns
common pathogens: chlamydia trachomatis (obligate intracellular)

highly evasive, establishes latent infections, weak secondary immunity
no vaccine but antibiotics are effective
common pathogens: treponema pallidum (spirochete)

1. incubation period (weeks)
2. primary stage: hard chancre (sore) at infection site, heals (latent stage follows, weeks to years)
3. secondary stage: rashes, skin/mucous membrane lesions, which later heal (latent stage follows)
4. Tertiary stage: gummas (granulomas) form in tissues (severly damage CNS, heart, other organs)

mental and physcial abnormalities

latency in neuron
HSV-1: oral infections
HSV-2: genital infections
neonatal herpes can be lethal

latent herpesvirus
can cause disseminated infection in newborns and immunocomprimised individuals

causes genital warts and cervical cancer
vaccine available

called otitis media
infants eustachian tube is at a lower angle (10 degrees)
common pathogens: streptococcus pneumoniae and haemophilus influenzae

most common infectious disease
lytic but typically cause mild disease
common pathogens: rhinoviruses, coronaviruses, adenoviruses

inflammation of larynx, barking cough, typically self-limiting
common pathogens: parainfluenza virus

also known as Group A Strep (GAS), many strains
often produce exotoxins (e.g. hemolysins)
prompt antibiotic treatment important

A. pharyngitis (strep throat)
-pus in lymph tissue, fever, very contagous
B. scarlet fever (exotoxin)
-causes fever and red rash, now less virulent in US

autoimmune complication of S. pyogenes infection
can result in heart and kidney damage, inflammation of joints
result of molecular mimicry

gram (-) with capsule
droplet transmission, attatches to ciliated epithelial cells in trachea, toxins lyse cells
inflammation, mucous, blocked airways, violent coughing, cyanosis result
DTaP acellular vaccine
common pathogens; bordella pertussis

site of gas exchange (O2 and CO2)

droplet or contact transmission
high fever, cough, blood/pus in mucous
10-30% mortality in US (elderly)
Many strains, little immunity
common pathogens: 90% streptococcus pneumoniae, pseudomonas aeruginosa (HIA)

top bacterial killer worldwide
waxy cell prevents desiccation as well as efficient phagocyte killing
long generation time (~18 hours)
common pathogens: mycobacterium tuberculosis

lower respiratory infection
mild in most, some infants suffer
vaccine available

acute sudden headache, neckache, fever, confusion, CNS inflammation/damage
often fatal

primarily in teens/20s
pharynx colonized, invades blood, crosses blood brain barrier, infects meninges
vaccine exists
common pathogens: neisseria meningitidis

A. streptococcus pneumoniae (infants and older adults)
B. haemophilus influenzae (Hib vaccine used in infants)
C. listeria monocytogenes (foodborne, crosses placenta, infants and older adults)

gram (+) strict anaerobe, endospores from soil germinate in deep wounds
tetanospasmin exotoxin (neurotoxin) causes rigid peralysis
anti-toxin antibody can neutralize toxin (passive immunity)
toxoid vaccine (DTaP) provides active immunity
common pathogens: clostridium tetani

endospores in soil
neurotoxin inhibits muscle contraction, causes flaccid paralysis, potential respiratory failure
prevents acetylcholine neurotransmitter release from motor neurons
treat with anti-toxin
common pathogens: clostridium botulinum

foodborne intoxication
infant: endospores consumed (e.g. in soil, honey)
wound: spores germinate in necrotic tissue

transmitted via mammal bite, virus in neurons, saliva
slowly invades CNS, sevre neurological damage
~100% mortailty w/o post-exposure immunization

cause brain inflammation
mosquito vector common, often bird reservior
west nile, eastern and western equine encephalitis viruses

nearly eradicated
fecal-oral transmission

endemic to Asia
rodent reservoir, flea is insect vector
pathogen evades phagocytosis, can lyse phagocytes
common pathogen: yersinia pestis gram (-) bacillus

bubonic: lymph node inflammation, hemorrhages result in buboes
septicemic: sepsis
pneumonic: lung infection

most common vector borne disease in US
zoonotic: tick vector, mice are reservoir
bull's eye rash, headache, muscle/joint pain
can progress into chronic arthritis, nervous system damage, heart arrhythmia
common pathogen: borrelia burgdorferi (spirochete)

obligate intracellular parasites, use arthropod vectors
invade endothelial cells, cause petechiae rash
fever, headache, rash, liver/spleen inflammation

1. endemic typhus (poor sanitation, conflict areas)
humans only, body louse vector, often fatal
common pathogen: rickettsia prowazekii
2. rocky mountain spotted fever
mid-south US
tick vector, highest mortality of tick borne diseases
common pathogen: rickettsia rickettsii