Coagulases

β-lactamases

Hydrolases

Staphylokinases

Hyaluronidases

Lipases

Staph Exotoxins

Leucocidins

Hemolysins

Enterotoxin

Exfoliatin

DNases

Streptokinases

Hyaluronidases

Proteases

-Strep pyogenes

-Staph aureus

Streptococcus

- Oral penicillin

- mupirocin ointment

Staphylococcus

- Oral, ointment

- cephalosporin, methicillin

- mupirocin ointment

Proper Cleansing

Proper care for wounds

- Staphylococcus aureus

- Exfoliatin causes blistering of the skin

- Dehydration from water loss through skin

- Treated with intravenous antibiotics

- Invasive Streptococcus (Group A)

- Exotoxin A (Super Antigen)

-- Causes nonspecific T-cell Activation

-- Massive cytokine release

- Causes massive skin damage

- Treated with surgery and intravenous antibiotics: penicillin, vancomycin & clindamycin

- blocked sebum ducts

-- Overproduction of androgens results in the overproduction of sebum

- Propionibacterium acnes

- causes pustules

- Nodular or cystic acne is much worse

- Treatments include benzoyl peroxide, tetracycline (protein synthesis inhibitor), doxycycline & isotretinoin (accutane)

Hansen's disease (1873)

- Mycobacterium leprae

- acid-fast rods (resist acid-alcohol decolorizing agents resulting in a false gram+ stain)

- intracellular (macrophage)

- skin, nerves, URT

- skin to skin or aerosol propagation

- cooler portions of body

- armadillos(1975), mouse toe pads

- weeks to years incubation

- 12 MM worldwide

- 100 new cases a year 

- cell-mediated response

- lesions

-- granulomas

- loss of sensation

- not very contagious

Treatments: rifampin (↓ RNA transcription), dapsone (Multidrug therapy with rifampin)

- Skin / peripheral nerves

- Progressive tissue damage (inflammation); bone resorption

- foam cells / disfiguring dodules (leproma)

- contagious

- rifampin, dapsone, clofazimine

- opportunistic, G- rods

- hot-tub folliculitis, otitis externa

- burn, cancer patients, diabetics, CF kids

- blue-green pus (pyocyanin)

-exotoxin (diphtheria-like), endotoxin

Treatment: fluoroquinolones (Cipro) (↓ DNA replication), gentamicin

- Borrelia burgdorferi

- G- spirochaete

- ixodid tick = vector

-- tick infected by first blood meal and can pass on infection to human in second blood meal

- field mouse = reservoir

- bull's eye rash after 3-30 days

- Flu-like symptoms, meningitis, heart damage, arthritis, neurological

- +ELISA test - confirm with western blot

Treatment: amoxicillin, doxycycline

- enzyme-linked immunoabsorbent assay

- direct - to detect antigens

- indirect - to detect antibodies (Lyme)

Rickettsia rickettsii

- intracellular G- rod (depend on energy from host cell)

- Vectors: ticks, lice, fleas, mites

-- transovarian passage - doesn't require reservoir

- Reservoirs: ticks, rodents, dogs

- Fever, headache, vomiting, macular rash around wrists, forearms & ankles 

- Later (6+ days) - spotty (petechial) rash begins palms, soles, progresses to trunk

- attack endothelium of vascular system

- doxycycline, chloramphenicol

- untreated - 20% mortality

Tinea- , -pedis, -capitus, -corporis, -cruris, -barbae

Trychophyton, Microsporium, Epidermiphyton (digest keratin)

- propagated by direct contact & fomites

- waste products cause inflammation

Treatments: miconazole, clotrimazole, griseofulvin(oral)(inhibits formation of spindle apparatus)

Candida albicans - opportunistic yeast

- normal flora - skin, GI, respiratory, urogenital

- pathogenic when there are predisposing factors

 - red, swollen, scaly skin

- mouth (thrush); vaginal

Treatment: miconazole, clotrimazole (lozenges), nystatin(topical), oral ketoconazole, amphotericin B

- immunosuppression

- diabetes

- leukemia

- excess moisture

- obesity

- TB, AIDS

- prolonged antibiotic use

- ds, DNA, enveloped

- skin, eye, mucous membrane, nervous system, peripheral sensory nerves to ganglia (trigeminal)

- Propagated by direct contact, aerosols, fomites

- vesicles - rupture, scaly, 7-10 days

- dormancy in trigeminal nerve - reactivation by stress, sun or hormone levels

- encephalitis (temporal) - more serious if HHV2

Treatment: acyclovir - inhibits viral replication - reduces severity of symptoms

Chicken pox

- Human Herpes Virus III

- ds, DNA, enveloped

- invades URT

- Propagated by respiratory secretions / contact

- 15-20 day incubation

- Children (5-9 yrs)

- evolution of lesions

-- macules, vesicles, pustules, scabs

- scalp & face, then trunk, arms & legs

- Live, attenuated virus vaccine - 2 doses

-- 12-18 months & 4-6 yrs

- Latency in dorsal root ganglia & cranial nerves

- Adult sequelae - encephalitis, pneumonia, extensive vascular damage

Human Herpes Virus III

 - Shingles - vesicular lesions around the girdle

-- painful, burning & itchy

-- inflammation of the sensory nerves

- Reactivation of virus by trauma, stress or suppressed cell-mediated response

Treatment: antiinflammatory (not asprin), acyclovir, zostavax(attenuated virus, > 60 y/o's, 50% efficacy)

- inflammatory response

- cell-mediated response to lyse infected cells

paramyxovirus

- ss-, RNA, enveloped

- propagated by respiratory secretions

- invades URT; 7-12 day incubation

- early cold-like symptoms, Koplik's spots, fever

- macular rash on face & neck

- damage from secondary infections

- MMR vaccine at 12-15mo & 4-6 yrs

- togavirus - ss+, RNA, enveloped

- infects URT

- Propagated by nasal secretions & direct contact

- 10-21 day incubation

- macular rash (trunk), low fever

- congenital rubella (at birth) - eye/brain damage, deafness, heart abnormalities, liver disorders, low birthweight, still birth

Impact this disease once had on the human population

- China & far east

- 1157 B.C. - Ramses V

- 710 A.D - Europe

- 1520 - hernando cortez

-- 3.5 million aztecs died (naive population)

- 1700's europe, smallpox plague

- pox virus - ds DNA, enveloped

- eradicated by WHO campaign in 1967

- Propagated via respiratory

- destruction of sebaceous glands cause skin lesions

- papilloma virus - ds DNA

- introduced; long incubation(months-years)

- small tumors with viruses

- propagated by direct contact and fomites

- Dura Mater

- CSF in subarachnoid space

- Pia Mater

- more life threatening than viral meningitis

- part of normal flora

- spread via aerosols & fomites

- often infect nasopharynx, sinuses & middle ear

- lungs

- capsules

- rapid onset of headache, fever, stiff neck, muscle & back pain, nausea & vomiting

- continuing symptoms: fever, drowsiness, confusion, inconsciousness

- blood & pus block flow of CSF - leads to seizures, paralysis, coma

- infant symptoms: lethargic, listless, irritable, feed poorly, fever & vomiting

- diagnosis from CSF - gram stain, culture

- ampicillin, penicillin (Neisseria), cephalosporins (Strep. & Haemophilus)

Neisseria meningitidis

- G- coccus

- capsule, fimbriae

- 13 serogroups

-- B&C most commonly found now

-- A&C most common in pre WW2 epidemics

- IgA protease, necrotizing factor, purpuric rash

- under 40, teens

- 70-90% untreated mortality rate

- vaccine is a capsular polysaccharide, no vaccine for serotype B

- high carrier rate

- Streptococcus pneumoniae

- G+ coccus

- α-hemolytic

- 23-valent polysaccharide vaccine + booster for adults

- conjugate vaccine for infants/young children

- Haemophilus influenzae

- G- coccobaccilus

- Children

- Sequela to other infections

- lower mortality

- CNS damage - hearing loss common

- Hib - conjugate vaccine

- Clostridium tetani

- anaerobe, G+ bacillus

- soil, animal feces

- wound entry - puncture wound

- resistant spores

- tetanospasmin - spastic paralysis - inhibits release of inhibitory neurotransmitter

- toxoid vaccine (DPT) & boosters

- antitoxins, penicillin, clindamycin, erythromycin

- Rhabdovirus - ss-, RNA, enveloped

- spread via bites & aerosols

- spreads slowly, 6-12 weeks if leg bitten

- no symptoms until in CNS

- malaise, fever, weakness, paralysis/muscle spasms, renal failure, coma, encephalitis, death

- Human diploid cell vaccine + RIG

-- post-exposure vaccine

- raccoons are the most common reservoir

- picornavirus - ss+, RNA

- spread person to person, contaminated water

- throat, intestines → blood (viremia)

- rarely invades CNS - motor neurons / brain

- Salk (inactivated) & Sabin (attenuated)

- high fever, back pain, muscle spasms

- anterior horn

- arboviruses

-- alpha viruses (toga-) (+RNA), enveloped

-- wild fowl, rodents, horses - reservoirs

- mosquito - vector

-- eastern equine - very high rate of brain damage

- enteroviruses, herpes viruses, HIV

- fever, headache, chills, vomiting, brain swelling

- Flavivirus (+)RNA, enveloped

- Uganda 1937

- mosquito vector

- birds*, cats horses, rodents rabbits

- fever, headache, muscle/back aches, decreased appetite, nausea, vomiting, diarrhea, rash, swollen lymph glands

- Mumps virus, enteroviruses

- URT, fecal/oral

- herpes virus, HIV

- no bacteria in CSF

Conjunctivitis

- allergic reaction, viral

- Heamophilus influenzae, Streptococcus pneumoniae

- Cryptococcus neoformans

- resemble yeasts, live in soil - bird droppings

- inhalation of dried droppings

- infects LRT - gradual onset

- brain & meninges (HIV)

- amphotericin B & flucytosine

- 90% vs 30% mortality

- Naegleria fowleri

- amoeba - ponds, streams (warm freshwater)

- infectious stage of protozoan is flagellate

- Children - enters nasal mucosa

- rapid onset, difficult diagnosis

- amphotericin B

- headache, fever, chills, stiff neck, vomiting, various, neurological dysfunction

- 98% mortality without treatment

Trypanosoma brucei gambiense

-flagellate

- vector is the tsetse fly

- progressive, chronic

- melarsoprol - arsenic (late treatment) - shuts down principal enzymes of glycolytic pathways

- pentamidine (early treatment) - inhibit replication

- tired during day, awake at night

- starts in blood and takes unpredictable route to CNS - may take weeks

- hallucinations, convulsions, etc.

- inflammation - glandular swelling, sore throat, fever, malaise, scarlet color, pyogenic exudate

- transmission: droplets, contact

- causes: Streptococcus pyogenes (Group A, β hemolytic), Staph., Haemophilus influenzae, Corynebacterium diphtheriae

Treatment: penicillin, amoxicillin, azithromycin, cephalosporins

- pharyngotonsillitis

- Strep. pyogenes - lysogenized by bacteriophage

- erythrogenic toxin - damage to small blood vessels, rash starting on chest, armpit & behind the ears, strawberry tongue

- Strep. sequelae

- asymptomatic carriage of Group A Strep. in throat

- arthritis & carditis, acute nasopharyngitis, electrocardiac changes, fever, inflammation of joints & heart

- Ab's produced against Strep products cross react with host cell antigens in heart or joint tissue

Treatment: penicillin at low levels for a long time, anti-inflammatories

- scarlet fever predisposes

- pharyngotonsillitis sequela

- circulating antigen/antibody complexes deposited in glomerulus

- hematuria, anuria, swelling, hypertension, may develop delirium, coma, rarely fatal

- lysogenized Corynebacterium diphtheriae

- G+ nonmotile, pleomorphic rods

- Chinese lettering, club shaped

- Exotoxin is primary cause of death

-- Frag. A - modifies EF2

-- Frag. B binds to receptor cells & increases transport of bacteria into cells

- inhibits protein synthesis in heart, kidney & peripheral nerves

- sore throat, fever, headache, glandular swelling (bull neck), grayish pseudomembrane (necrotic cells, fibrin, human cells, white blood cells)

- spread by asymptomatic carriers via aerosols & fomites

Treatment: erythromycin, penicillin, antitoxin

- DPT vaccine (toxoid)

- Sequelae - myocarditis, kidney & nerve damage - death

- pain/tenderness in forehead, purulent discharge

- Haemophilis influenzae, Strep. pneumoniae, Strep. pyogenes, Staph. aureus & viruses

Treatment: drainage of sinuses and antibiotics, moist heat, vasoconstrictors(pseudoephedrine)

-Zygomycoses (fungal)

- Rhizopus, Mucor, Aspergillus

- opportunistic, arterial blood

- develop rapidly

- characterized by black mucous

- may spread to brain

Treatment: correct predisposing factors (deviated septum, rhinitis, polyps), amphotericin B, imidazoles

- inflammation of external ear - infection

- moisture accumulation or damage

- pain, itching, crusting or pus

- variety of G+ cocci, G- bacilli and fungi

-- Pseudomonas aeruginosa - resistant to chlorine, swimmers, green pus coming out of ears

Treatment: tetracycline, carbinicillin

- perforation in eardrum may lead to nerve damage

- Nose/Throat infections

- Acute

-- Haemophilis influenzae, Strep. pneumoniae, Strep. pyogenes

- Chronic

-- Proteus, Klebsiella, Pseudomonas

- stuffy nose, scratchy throat, headache, sore throat, sneezing, watery nasal discharge (may thicken and turn yellow)

- rhinoviruses (+RNA) - spring/fall

- coronaviruses (-RNA, enveloped) - winter colds - may attach to GI tract & cause diarrhea, dehydration & electrolyte imbalance

- adeno-, influenza, myxo-, coxsackie

- respiratory syncytial viruses (-RNA, env) - children

- Spread via person to person, person to fomite to person

Treatment: hard to develop a vaccine, treat symptoms, interferon treatment

Viral URT disease

- parainfluenza (paramyxovirus, -RNA, env)

- begins with nasal discharge, dry cough

- obstruction of upper airway

- sudden onset, coughing, hoarseness, barking sounds, fever

- earache, pneumonia(rare)