Week 6 Microbiology eDapt Flashcards

What are three ways the skin protects against microbes?

Sweat, sebum, and shedding of skin cells.

Think: The skin fights microbes with sweat, oil, and “goodbye” shedding.

Why does broken skin increase infection risk?

Cuts, abrasions, and punctures allow microbes to enter deeper tissues.

Think: Broken skin = open door

What is keratitis?

Infection/inflammation of the cornea.

Think: Keratitis → think cornea

What can cause keratitis?

Herpes simplex virus, Acanthamoeba, and various bacteria.

Think: Keratitis has multiple possible causes.

What causes trachoma?

Chlamydia trachomatis

Think: Chlamydia → trachoma

What causes river blindness?

Onchocerca volvulus

Think: Onchocerca → “O” = ocular/eye → blindness

What organism can cause conjunctivitis?

Neisseria gonorrhoeae, Chlamydia trachomatis, various bacteria, and viruses

Think: Conjunctivitis = pink eye 0 → lots of possible pathogens

Skin Infections: What causes hand, foot, and mouth disease?

Coxsackievirus

Think: Coxsackie = hands + feet + mouth

What causes scalded skin syndrome?

Staphylococcus aureus

Think: Staph → scalded skin

What organisms commonly cause impetigo?

Staphylococcus aureus and Streptococcus pyogenes

Think: Impetigo = Staph + Strep

What organisms commonly cause cellulitis?

Staphylococcus aureus and Streptococcus pyogenes

Think: Cellulitis = Staph + Strep

What causes gas gangrene?

Clostridium perfringens

Think: C. perfringens → gas gangrene

What causes MRSA skin and soft tissue infections?

Methicillin-resistant Staphylococcus aureus.

Think: MRSA literally contains SA = Staph aureus

What viruses cause maculopapular rashes?

Measles virus, rubella virus, Parovirus B19, and HHV-6

Think: “viral rash group”

What virus causes chickenpox?

Varicellar-zoster virus (HHV-3)

Think: Varicella = chickenpox

What virus causes smallpox?

Variola virus

Think: Variola = smallpox

What viruses cause warts and wartlike eruptions?

Human papillomaviruses (HPV) and molluscum contagiosum viruses.

Think: HPV = warts

What are the 3 major dermatophyte genera?

Trichophyton, Microsporum, and Epidermophyton

Think: T-M-E = the dermatophyte trio

What is another important fungus associated with superficial mycoses?

Malassezia

Think: Malassezia = superficial skin fungus

MRSA

Methicillin-resistant Staphylococcus aureus.

Think: MRSA = Mega Resistant Staph.

Typical signs of an MRSA skin infection

Raised, red, tender, hot lesions that often contain pus.

Think: Red + hot + painful + pus = MRSA.

How MRSA commonly enters the body

Through breaks in the skin, such as surgery, injury, shaving, or abrasions.

Think: Broken skin = open door.

Transmission of MRSA

Through fomites and contact with contaminated objects.

Think: Fomites = MRSA gets a ride.

Medication of choice for MRSA

Vancomycin.

Think: MRSA → Vanco.

Common bacteria causing necrotizing fasciitis

Streptococcus pyogenes and Staphylococcus aureus.

Think: Necrotizing fasciitis = Strep + Staph.

Early sign of necrotizing fasciitis

Severe/intense pain with a hot, sunburn-like rash.

Think: Crazy pain + sunburn-like skin = 🚨.

Function of superantigens

They cause excessive T-cell activation and cytokine release, which can lead to shock.

Think: Superantigen = immune system OVERDRIVE.

Treatment for necrotizing fasciitis

Broad-spectrum antibiotics and surgical removal of dead tissue; severe cases may require amputation.

Think: Antibiotics + CUT OUT the dead tissue.

Causes of gas gangrene (clostridial myonecrosis)

Clostridium perfringens.

Think: C. perfringens → gas gangrene.

Major virulence factors of C. perfringens

Alpha toxin, other exotoxins, enzymes, and gas production.

Think: Toxins + enzymes + GAS = tissue destruction.

Anaerobic cellulitis

A form of gas gangrene that remains localized.

Think: Anaerobic cellulitis = stays put.

True myonecrosis

A form of gas gangrene that spreads into healthy tissue.

Think: Myonecrosis = muscle death that MOVES.

Conditions for C. perfringens toxin production

Under anaerobic (low/no oxygen) conditions.

Think: Clostridium → low oxygen.

Locations of C. perfringens endospores

Soil, human skin, human intestine, and vagina.

Think: C. perfringens spores are common in the environment and body.

Treatment for gas gangrene

Clindamycin + penicillin, surgical removal of dead tissue, and oxygen therapy.

Think: Kill it + cut it out + oxygen.

Prevention of gas gangrene

Clean wounds and remove dead tissue.

Think: Clean + debride = prevent.

What disease was the first to be eradicated through a successful vaccination program?

Smallpox.

Think: Smallpox = the famous eradicated disease.

What are the characteristic lesions of chickenpox?

Itchy vesicles filled with clear fluid.

Think: Chickenpox = itchy clear-fluid bubbles.

Where does the chickenpox rash typically begin and where does it spread?

It begins on the back and trunk and spreads to the face, neck, and limbs.

Think: Trunk first → spreads outward.

How is chickenpox transmitted?

By inhalation of the virus or direct contact with skin lesions.

Think: Chickenpox = breathe it in or touch the lesions.

How are uncomplicated cases of chickenpox treated?

Usually no treatment is needed; antivirals such as acyclovir may be used for high-risk cases.

Think: Normal case = supportive care; high-risk = antiviral.

What type of vaccine is used for chickenpox?

A live attenuated vaccine.

Think: Chickenpox vaccine = weakened live virus.

What causes shingles?

Reactivation of latent varicella-zoster virus (VZV).

Think: Shingles = sleeping VZV wakes up.

Where does VZV become latent after chickenpox?

In sensory nerve ganglia.

Think: VZV hides in the nerves.

What is the characteristic distribution of shingles lesions?

Densely packed lesions usually localized to a single dermatome on one side of the body.

Think: Shingles = ONE-SIDED nerve band.

Why is shingles usually limited to one side of the body?

The reactivated virus travels along a specific sensory nerve/dermatome to the skin.

Think: One nerve → one skin territory.

What vaccine is available to help prevent shingles?

A shingles vaccine.

Think: Chickenpox vaccine prevents chickenpox; shingles vaccine helps prevent reactivation disease.

What is a maculopapular rash?

A rash consisting of flat (macular) and slightly raised (papular) colored bumps.

Think: Macule = flat + papule = raised.

What causes rubella (German measles)?

Rubivirus.

Think: Rubella → Rubivirus.

What are the main symptoms of postnatal rubella?

Pink rash, fever, and swollen lymph nodes.

Think: Rubella = pink rash + lymph nodes.

Why is rubella especially dangerous during pregnancy?

The virus can cross the placenta and cause serious developmental problems in the fetus.

Think: Rubella during pregnancy = baby at risk.

What are major complications of congenital rubella?

Deafness, cardiac abnormalities, ocular lesions, developmental problems, and miscarriage.

Think: Congenital rubella → ears + heart + eyes + development.

How is rubella transmitted?

Through respiratory secretions.

Think: Rubella spreads through respiratory secretions.

How is rubella prevented?

Live attenuated MMR or MMRV vaccine.

Think: Rubella → MMR.

What causes measles (rubeola)?

Morbillivirus.

Think: Measles → Morbillivirus.

What are common early symptoms of measles?

Fever, sore throat, headache, dry cough, and conjunctivitis.

Think: Measles = fever + cough + red/irritated eyes.

What are Koplik's spots?

Lesions that appear on the mucous membranes of the mouth during measles infection.

Think: Koplik's = spots in the mouth.

What type of rash does measles cause?

A red maculopapular rash.

Think: Measles = red maculopapular rash.

How is measles transmitted?

Through respiratory droplets.

Think: Measles = extremely contagious airborne/respiratory spread.

What is the most severe complication of measles?

Subacute sclerosing panencephalitis (SSPE), a progressive neurological degeneration.

Think: Measles → SSPE → brain degeneration.

How is measles treated?

Symptomatic treatment; antibiotics may be used for secondary bacterial infections.

Think: Treat symptoms; antibiotics only if bacteria join the party.

How is measles prevented?

Live attenuated MMR or MMRV vaccine.

Think: Measles → MMR.

What is the cornea?

The transparent layer covering the iris.

Think: Cornea = clear window over the iris.

What is the conjunctiva?

A thin layer covering the sclera and palpebral fissures.

Think: Conjunctiva = thin covering around the eye.

What is conjunctivitis?

An infection/inflammation of the conjunctiva caused by various microorganisms.

Think: Conjunctivitis → conjunctiva → pink eye.

What type of exudate suggests bacterial conjunctivitis?

Mucopurulent discharge.

Think: Bacteria = pus-like discharge.

What type of exudate suggests viral conjunctivitis?

Clear exudate.

Think: Virus = clear/watery discharge.

What causes trachoma?

Chlamydia trachomatis.

Think: Chlamydia → Trachoma.

What type of bacterium is Chlamydia trachomatis?

A Gram-negative bacterium that grows intracellularly.

Think: Chlamydia = lives inside cells.

What can chronic trachoma cause?

Chronic inflammation and scarring of the epithelial cells of the eye.

Think: Trachoma = chronic infection → scarring.

How is trachoma transmitted?

Through indirect contact and mechanical vectors.

Think: Trachoma = contact + vectors.

What drugs can treat trachoma?

Oral azithromycin or doxycycline.

Think: Trachoma → azithro or doxy.

How can trachoma be prevented?

Good hygiene, vector control, and prompt treatment.

Think: Clean + control vectors + treat quickly.

What does "axenic" mean?

An environment that has no normal microbiota.

Think: Axenic = absolutely no normal microbes.

Why is the CNS considered an axenic environment?

The brain and spinal cord normally contain no microbiota.

Think: CNS = microbiota-free VIP area.

What structures protect the brain and spinal cord from infection?

The meninges and blood-brain barrier (BBB).

Think: Meninges + BBB = CNS security system.

What are the meninges?

Protective membranes surrounding the brain and spinal cord.

Think: Meninges = protective wrapping.

What is the blood-brain barrier (BBB)?

A protective barrier that limits substances and microorganisms in the blood from entering the brain.

Think: BBB = brain security checkpoint.

How can microorganisms enter the CNS through damaged barriers?

Breaks in the meninges or blood-brain barrier can allow microbes to enter.

Think: Broken barrier = open door.

What is axonal transport?

Movement of microorganisms along peripheral nerve axons into the CNS.

Think: Axons = microbial highways.

How can microbes in the blood or lymph enter the CNS?

They can penetrate the blood-brain barrier by infecting and killing cells of the meninges.

Think: Blood/lymph = microbial delivery system.

What are the two major routes microorganisms can use to reach the CNS?

Through breaks in protective barriers or through axonal transport from the PNS; microbes can also reach the CNS through blood or lymph.

Think: Break in → nerve highway → bloodstream.

What is bacterial meningitis?

Inflammation of the meninges caused by bacteria.

Think: Meningitis = inflamed meninges.

What are the five major bacteria associated with bacterial meningitis in this section?

Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus agalactiae, and Listeria monocytogenes.

Think: N-S-H-S-L = major bacterial meningitis group.

What are common signs of bacterial meningitis?

Sudden high fever, intense meningeal inflammation, and increased WBCs in CSF.

Think: Meningitis = fever + inflamed meninges + WBCs.

What is an important virulence factor of Neisseria meningitidis?

Its polysaccharide capsule and LOS endotoxin are important virulence factors.

Think: Neisseria = capsule + endotoxin.

How is Neisseria meningitidis transmitted?

Respiratory droplets.

Think: Meningococcus = respiratory spread.

How is Neisseria meningitidis meningitis treated?

Ceftriaxone or penicillin.

Think: Neisseria → ceftriaxone/penicillin.

How can N. meningitidis meningitis be prevented?

Vaccination and prophylactic antibiotics for close contacts.

Think: Protect yourself + protect the contacts.

Which bacterium causes the largest proportion of meningitis cases in the U.S. according to this material?

Streptococcus pneumoniae (58% in the provided material).

Think: Pneumococcus = major meningitis cause.

What is an important virulence factor of S. pneumoniae?

Its polysaccharide capsule.

Think: Pneumococcus = protective capsule.

What vaccines help prevent S. pneumoniae infections?

Prevnar and Pneumovax.

Think: Pneumococcus → pneumococcal vaccines.

What is an important virulence factor of H. influenzae?

Its polysaccharide capsule.

Think: H. influenzae = capsule.

How is H. influenzae meningitis treated and prevented?

Ceftriaxone for treatment; Hib vaccine and antibiotics for prevention.

Think: Hib → ceftriaxone + Hib vaccine.

Which bacterial meningitis pathogen is particularly associated with newborns?

Streptococcus agalactiae.

Think: S. agalactiae = newborn.

How do babies acquire S. agalactiae?

During passage through an infected birth canal.

Think: Birth canal → baby.

How is S. agalactiae treated?

Penicillin G and aminoglycosides.

Think: Agalactiae → penicillin G + aminoglycoside.

How is Listeria monocytogenes commonly transmitted?

Through contaminated food, particularly meat and under-pasteurized milk and cheese.

Think: Listeria = contaminated food.

What is a key characteristic of Listeria monocytogenes?

It is an intracellular pathogen and can survive cold, salt, and heat.

Think: Listeria = lives inside cells + tough survivor.

How is Listeria monocytogenes treated?

Ampicillin and gentamicin.

Think: Listeria → ampicillin + gentamicin.