Microbio Exam 4

S. aureus infection

abscesses, wound infections, necrotizing fasciitis, SSSS, and impetigo (skin)

S. pyogenes infection

impetigo, erysipelas, cellulitis, major cause of necrotizing fasciitis (skin)

Bacillus anthracis infection

cutaneous anthrax (skin)

Neisseria gonorrhoeae infection

gonococcal conjunctivitis (eye)

Chlamydia trachomatis

trachoma, inclusion conjunctivitis (eye)

Haemophilus influenzae

bacterial conjunctivitis (eye)

Measles virus infection (morbillivirus hominis)

measles (rubeola)

Rubella virus infection (rubivirus rubellae)

rubella (german measles)

Varicella-zoster virus infection

chickenpox, shingles

Trichophyton, Microsporum, Epidermophyton (fungi)

dermatophytosis (ringworm/tinea)

Coagulase test

detects coagulase activity; positive result = clumps

Catalase test

detects catalase; positive result = bubbles on slide

Staphylococci catalase test results

positive

Streptococci catalase test results

negative

S. aureus coagulase test result

positive

What do Staphylococcus aureus strains produce that cause tissue damage?

cytotoxins

MRSA

a strain of S. aureus resistant to methicillin and most other beta-lactam antibiotics

What makes cellulitis unique concerning the location in the skin?

it infects the dermis and subcutaneous tissue

Tinea capitis

scalp

Tinea barbae

beard

Tinea pedis

foot

Tinea cruris

groin

Tinea corporis

body

Tinea unguium

nails

What tests are used to identify measles infections?

ELISA test

How measles can affect cells and tissues

disrupts cell division, triggers cell death, damages vascular endothelium

Ways to reduce the risk of acquiring fungal infections in shared public spaces

keep skin clean and dry, avoid sharing personal clothing, wear shoes in public areas, avoid direct contact with infected, wash clothing, towels, and bedding

Multinucleated system

a large single, cellular mass that contains multiple nuclei sharing a common cytoplasm; associated with RSV

Neisseria meningitidis type and exposure clues

bacterium in nasopharynx; spreads through close contact with respiratory or throat secretions

Neisseria meningitidis risk or damage clues

capsule helps it evade phagocytosis, endotoxin drives inflammation, bloodstream infection can cause petechiae or purpura

Streptococcus pneumoniae type and exposure clues

bacterium in the nasopharynx; an important cause of community-acquired meningitis in adults.

Streptococcus pneumoniae risk or damage clues

capsule helps it evade phagocytosis; pneumolysin and hydrogen peroxide
can damage host cells and contribute to inflammation

Hib (Haemophilus influenzae type b) type and exposure clues

bacterium in the upper respiratory tract; spreads through respiratory droplets or secretions.

Hib (Haemophilus influenzae type b) risk or damage clues

capsule helps it resist phagocytosis and can help it spread from the bloodstream to the meninges

Group B Streptococcus type and exposure clues

Bacterium associated with newborn meningitis; transmission commonly
occurs around delivery

Group B Streptococcus risk or damage clues

antibiotics during labor reduce the chance of transmission to the baby

Listeria monocytogenes type and exposure clues

bacteria most often acquired through contaminated food; can grow at refrigerator temps

Listeria monocytogenes risk or damage clues

greater risk for newborns, older adults, and people with weakened immune
systems; during pregnancy, it can cross the placenta

Cryptococcus neoformans type and exposure clues

encapsulated yeast usually acquired by inhaling environmental particles;
may be associated with soil, decaying wood, or bird-dropping-contaminated areas

Cryptococcus neoformans risk or damage clues

risk is greatest with advanced HIV/AIDS or other immune suppression; meningitis may develop gradually

Coccidioides species type and exposure clues

soil fungi; exposure may follow inhalation of dust from disturbed soil in
endemic areas

Coccidioides species risk or damage clues

usually begin in the lungs; rare spread to the meninges can cause serious disease

Viruses species

non-polio enteroviruses area common cause of viral meningitis; other causes include herpesviruses, mumps, and arboviruses

Viruses risk or damages clues

symptoms can resemble other forms of meningitis

Naegleria fowleri type and exposure clues

free-living ameba; contaminated warm freshwater must enter the nose

Naegleria fowleri risk or damage clues

travels toward the brain along olfactory nerves and causes rapidly progressing inflammation of the brain and meninges

Acanthamoeba type and exposure clues

free-living ameba found in soil, water, and dust; can enter through skin or the respiratory tract and spread through blood.

Acanthamoeba risk or damage clues

rare brain infection usually develops gradually; risk is greatest in people with weakened immune systems

Listeria monocytogenes

acquired from contaminated food, can cross the placenta during pregnancy

Listeria monocytogenes effects

pregnancy loss, preterm birth, or serious newborn infection

Zika virus

spread by aedes mosquitoes, can also pass from a pregnant person to a fetus

Zika virus effects

congenital zika syndrome can include microcephaly and eye or brain abnormalities

Toxoplasma gondii

a newly infected pregnant person can pass the parasite across the placenta

Toxoplasma gondii effects

fetal effects can include hydrocephalus or brain calcifications

Group B streptococcus

often transmitted to the newborn around birth, rather than across the placenta

Group B streptococcus effects

a cause of neonatal bacterial meningitis

Rabies

usually transmitted through bites or scratches from infected mammals;

Rabies target and key clues

travels through peripheral nerves to the CNS, incubation from weeks to months, PEP can prevent disease before symptoms begin

Poliomyelitis

mainly fecal-oral transmission through contaminated hands, food, or water

Poliomyelitis target and key clues

can destroy anterior horn motor nuerons, causing flaccid weakness or paralysis; sensation is usually preserved

Toxoplasmosis

may be acquired from undercooked meat or contaminated soil, food, or water

Toxoplasmosis target and key clues

dormant tissue cysts can reactive when immunity is severely weakened, causing encephalitis; infection during pregnancy can affect fetal barin development

Tetanus and Botulism are

gram-positive, spore- forming, anaerobic rods

Tetanus

releases tetanospasmin which inhibits signaling in the CNS causing sustained contraction, rigidity, and spastic paralysis

Botulism

releases botulinum toxin which releases acetylcholine at the neuromuscular junction causing weakness and flaccid paralysis

Tetanus prevention and treatment

routine vaccination; tetanus immune globulin can neutralize toxin that has not yet bound to nerve endings

Botulism prevention and treatment

antitoxin can stop additional toxin damage; supportive care may include ventilation, no vaccine available