Micro Exam 4 SG- Ch. 22-26

Epidermis

thin outer portion of skin

What is the epidermis made of?

layers of epithelial cells

Keratin

waterproofing protein coating outer layer of epidermis

Dermis

thick inner portion of skin

What is the dermis composed of?

primarily connective tissue

What do lysozymes do?

break down bacterial cell walls

The skin contains sebum secreted by oil glands containing

fatty acids that inhibit pathogens

Vesicles

small, fluid filled lesions

bullae

vesicles larger than 1cm in diameter

macules

flat, reddened lesions

pustules

raised lesions with pus

impetigo

Staphylococcal skin infection
crusting (nonbullous) sores
spread by autoinoculation

scalded skin syndrome

Staphylococcal skin infection.
bulbous impetigo
toxin B causes exfoliation

pemphigus neonatorum

impetigo of the newborn

toxic shock syndrome (TSS)

Staphylococcal skin infection
Fever, vomiting, shock, and organ failure caused by toxic shock syndrome toxin 1 (TSST-1) in the bloodstream

Acne

most common skin disease in humans

inflammatory (moderate) acne

caused by propionibacterium acnes
- metabolizes sebum; fatty acids produce an inflammatory response
treated with antibiotics and benzoyl peroxide

nodular cystic (severe) acne

inflamed lesions with pus deep in the skin

otitis externa

Infection by pseudomonas
"Swimmers ear"
Opportunistic in burn patients
Resistant to many antibiotics

necrotizing fasciitis

Streptococcal skin infection
"Flesh- eating" strep disease
Exotoxin A produced by S. pyogenes acts as a superantigen

measles (rubeola)

Viral disease transmitted by the respiratory route
Cold like symptoms, macular rash
Koplik's spots
Encephalitis in 1 in 1000 cases
Prevented by MMR vaccine

koplik's spots

red spots on the oral mucosa opposite the molars

Shingles (herpes zoster)

Reactivation of the latent varicella- zoster virus that moves along peripheral nerves to the skin.
- due to stress or lowered immunity
Follows the distribution of affected cutaneous sensory nerves.
- limited to one side of the body
Postherpetic neuralgia- very painful
Prevention via the zoster vaccine
Antiviral drugs may lessen symptoms.

Chickenpox (Varicella)

DNA virus, Herpes family
Herpesvirus varicella- zoster (human herpesvirus 3)
Transmitted via the respiratory route
Causes pus-filled vesicles
Virus becomes latent in the central nerve ganglia
Reye's syndrome
Prevented by a live attenuated vaccines
-breakthrough varicella can occur if previously vaccinated

Reye's syndrome

Severe complications of chickenpox; vomiting and brain dysfunction
-aspirin use increases risk

Warts

Papillomas
Transmitted via contact
Caused by papillomavirus
-more than 50 types
-some cause skin and cervical cancers
Treated with cryotherapy, electrodesiccation, or salicylic acid
Papilloma vaccine can prevent certain cervical cancers

papillomas

small skin growths

Rubeola

measles

varicella zoster

virus that causes chickenpox

Rubella

German measles
Macular rash and light fever
Transmitted via the respiratory route; 2-3 week incubation
Prevented by MMR vaccines

Papillomavirus

Causes warts

Herpes simplex virus I and II (HSV I, HSV II)

DNA viruses, herpes family
Usually develop as cold sores or fever blisters

HSV I

spread primarily by oral or respiratory routes

HSV II

spread primarily sexually

Conjuctivitis

Inflammation of the eye membrane (conjunctiva)
Also called red eye or pinkeye
Caused by bacteria or virus
Commonly caused by Haemophilus influenzae
Can be caused by pseudomonas associated with unsanitary contact lenses

CNS

Central nervous system
Composed of the brain and spinal cord

Blood- brain barrier (BBB)

Formed by epithelial cells of the capillary wall, astrocyte end- feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane.
Shields the brain from toxins in the blood.

Encephalitis

Inflammation of the brain

Meningitis

Inflammation of the meninges.

Tetanus

Caused by Clostridium tetani
Gram(+), endospore forming, obligate anaerobe
Grows in deep wounds
Tetanospasmin released from dead cell blocs relaxation pathway in muscles
Prevented by vaccination with tetanus toxoid (DTP) and booster (dT)

Poliomyelitis

Poliovirus
Transmitted by ingestions
Initial symptoms: sore throat and nausea
Viremia may occur; if persistent, virus can enter the CNS
Destruction of motor cells and paralysis occurs in

Rabies

Caused by rabies virus
Transmitted by animal bite

Furious rabies

Animals are restless then highly excitable

Paralytic rabies

Animals seem unaware of surroundings

Haemophilus influenzae Meningitis

Occurs mostly in children (6 months- 4 years)
Gram(-) aerobic bacteria, normal throat microbiota
Capsule antigen type B
Prevented by Hib vaccine

Neisseria meningitidis

Also called meningococcal meningitis
Caused by N. mengitidis: Gram (-), aerobic cocci with a capsule
10% of people are healthy nasopharyngeal carriers
Begins as throat infection, rash

Streptococcus pneumoniae Meningitis

Also called pneumococcal meningitis
Caused by S. pneumoniae (a gram+ diplococcus)
70% of people are healthy nasopharyngeal carriers
Most common in children (1 month- 4 years)
Mortality: 30% in children, 80% in elderly
Prevented by vaccination

Listeria monocytogenes

Gram (+) bacillus pathogen causing listeriosis

Clostridium tetani

Gram (+) pathogen causing tetanus

Poliovirus

Causes poliomyelitis

Rabies virus

Causes rabies

Listeriosis

Caused by Listeria monocytogenes
Gram(-) aerobic rod
Usually foodborne; can be transmitted to fetus
Reproduce in phagocytes

Cardiovascular & Lymphatic systems

Plasma leaves blood to become interstitial fluid
Lymph capillaries: transport interstitial fluid to blood
Lymph nodes contain: fixed macrophages, B cells, T cells

What do lymph nodes contain?

Fixed macrophages, B cells, T cells

What is the function of the lymphatic system?

Maintains fluid levels in body tissues by removing all fluids that leak out of blood vessels.

Septicemia

Persistent pathogens or their toxins in blood

Sepsis

Systemic inflammatory response

Septic shock

Sepsis + uncontrollable decreased blood pressure

Endocarditis

Inflammation of the endocardium

Anthrax

Bacillus anthracis: Gram(+), endospore- forming, aerobic rod
Found in soil
Cattle routinely vaccinated
Treated with ciprofloxacin or doxycycline

Infectious mononucleosis

Epstein- Barr virus (HHV-4)
Childhood infections are asymptomatic
Transmitted via saliva
Characterized by proliferation of monocytes

Cutaneous anthrax

Endospores enter through minor cut
20% mortality

Gastrointestinal anthrax

Ingestion of undercooked, contaminated food
50% mortality

Inhalational (pulmonary) anthrax

Inhalation of endospores
100% mortality

Staphylococcus aureus
Streptococcus pyogenes
Enterococcus faecium
Streptococcus agalactiae/ Group B Streptococcus

Gram (+) pathogens associated with nosocomial infections

Bacillus anthracis

Gram (+), endospore- forming, aerobic rod
Pathogen causing anthrax

Cytomegalovirus (CMV)

HHV- 5
Infected cells swell
Latent in white blood cells
May be asymptomatic or mild
Transmitted across placenta; may cause mental retardation
Transmitted sexually, by blood, or by translated tissue

Epiglottitis

Most life threatening disease of the upper respiratory system

Scarlett fever

Erythrogenic toxin produced by lysogenized S. pyogenes

Diphtheria

Caused by Corynebacterium diphtheriae
Forms a tough grayish membrane in the throat
-Fibrin and dead tissue
-Blocks passage of air to the lungs
Exotoxin produced by lysogenized bacteria: circulates in the blood; damages the heart and kidneys

Otitis media

Infection of the middle ear: formation of pus puts pressure on the eardrum
Causes: Streptococcus pneumoniae, nonencapsulated Haemophilus influenzae, Moraxella catarrhalis, S. pyogenes, respiratory syncytial viruses
Common in childhood due to smaller auditory tube
Treated with broad-spectrum penicillins

Viral pneumonia

Occurs as a complication of influenza, measles, or chickenpox

Q fever

Caused by Coxiella burnetti

Pertussis (whooping cough)

Caused by Bordetella pertussis
Produces a capsule: allows attachment to ciliated cells in the trachea: destroys ciliated cells and shuts down the ciliary escalator.
Tracheal cytotoxin of cell wall damages ciliated cells.
Pertussis toxin enters the bloodstream.

Tuberculosis

Caused by Mycobacterium tuberculosis

Acute Q fever

High fever, muscle aches, headache, coughing

Chronic Q fever

Endocarditis (may occur years after infection)

Pathogens that cause otitis media

Streptococcus pneumoniae
Nonencapsulated Haemophilus influenzae
Moraxella catarrhalis
S. pyogenes
respiratory syncytial viruses

Mycoplasma pneumonia

Pathogen causing Mycoplasmal pneumonia
No cell wall
Gram (-)

Coxiella burnetiid

Pathogen causing Q fever.
Obligately parasitic, intracellular gammaproteobacteria.
Gram (-)

Bordetella pertussis

Gram (-) coccobacillus pathogen causing pertussis (whooping cough)

Corynebacterium diphtheriae

Pathogen causing Diphtheria
Gram (+) rod; pleomorphic

Legionella pneumonia

Pathogen causing Legionellosis
Aerobic, gram (-) rod
Grows in water and air conditioning, biofilms, and waterborne amebae

Mycobacterium tuberculosis

Gram (+)
Pathogen causing Tuberculosis
Acid- fast rod; obligate aerobe
20- hour generation time
Lipids in the cell wall make it resistant to drying and antimicrobials.

Influenza virus

Contains 8 RNA segments and an outer lipid bilayer

Adenovirus

Causes mild cold or flu- like illness.

Rhinovirus

30%-50% of common cold
Thrives in temperatures lower than body temperature.

Coronavirus

10%-15% of common cold

Respiratory syncytial virus (RSV)

Most common viral respiratory disease in infants and
life-threatening pneumonia in older adults.
-almost all children are infected by age 2
-14,000 deaths annually, mostly in older adults
Causes cell fusion (syncytium) in cell culture
Coughing and wheezing for more than a week
Diagnosis: serological test for viruses and antibodies
Treated with palivizumab

Cholera

Acute diarrheal illness caused by infection of the intestine with Vibrio cholerae bacteria.

Salmonella gastroenteritis

Caused by salmonella enterica
Invades intestinal muscosa and multiples
-passes through M cells and enters the lymphatics
-replicates in macrophagesIncubation of 12-36 hours; fever, nausea, pain and cramps, diarrhea

Traveler's diarrhea

Most commonly caused by enterotoxigenic E. coli

Aflatoxin poisoning

Mycotoxins produced by Aspergillus flavus
-likely to be found on peanuts
-causes liver cirrhosis and liver cancer

Ergot poisoning

Mycotoxins produced by Claviceps purpurea
-occurs in grains
-restricts blood flow (gangrene) and causes hallucinations

Giardiasis

Caused by Giardia intestinalis
Prolonged diarrhea, malaise, weight loss, flatulence,
cramps.
Hydrogen sulfide detected in the breath or stools.
Diagnosed with microscopic examination of stool samples; CDC currently recommends serological fecal tests.
Treated with metronidazole and nitazoxanide.

Amebic dysentary

Caused by Entamoeba histolytica

Vibrio cholera

Gram (-) pathogen causing cholera

Escherichia coli

Gram (-). E. coli.

Campylobacter jejuni

Gram (-) micro aerobic
Causes campylobacteriosis

Helicobacter pylori

Gram (-) pathogen causing Helicobacter peptic ulcer disease.
Infects 30–50% of the population in the developed world
- grows in the stomach acid by producing urease: converts urea to alkaline ammonia
- disrupts stomach mucosa, causing inflammation