Chapter 18 Flashcards
What is the causative agent of Roseola?
Human herpesvirus 6
What are the signs/symptoms of Postnatal Rubella?
Malaise, mild fever, sore throat, lymphadenopathy, pink maculopapular rash
How is MRSA diagnosed?
PCR; inoculation on blood agar
What is desquamation?
The shedding of the skin in scales
What is the causative agent of rubella?
Rubivirus
Why is S. aureus considered the sturdiest of all non-endospore forming microbes?
It can withstand high salt, pH extremes, high temperatures, and air drying
What does MRSA stand for?
Methicillin-resistant Staphylococcus aureus
How does MRSA spread from host to host?
Direct contact and indirect contact via fomites
What type of virus is HHV3?
An enveloped DNA virus
What is shingles?
Reemergence of the chickenpox virus after a latent period; lesions form on one side of the body; pain and tenderness also occur
What is the conjunctiva?
A thin, membrane-like tissue that covers the eye
What are the signs/symptoms of chickenpox?
Fever, abundant rash in a centripetal pattern (more on trunk than extremities)
How is SSSS treated?
Antibiotics; current recommended drug is Cloxacillin
What is the stratum corneum?
The outermost layer of the epidermis
What is conjunctivitis?
Inflammation of the conjunctiva, combined with a milky (bacterial) or clear (viral) discharge, redness, and eyelid swelling
How are warts transmitted?
Direct and indirect contact, autoinoculation
What are the characteristics of Streptococcus pyogenes?
gram-positive, coccus, Lancefield Group A, beta-hemolytic on blood agar
What is the treatment for cellulitis?
Oral antibiotics for mild cases, intravenous antibiotics and debridement for severe cases
During which stages is a person with measles contagious?
Incubation, prodome phase, and skin rash phase
What is keratinitis?
A more serious eye infection that conjunctivitis; invasion of deeper eye tissue occurs and can lead to complete corneal destruction
What is a papule?
Small, elevated, solid bump
What are the signs/symptoms of cellulitis?
Pain, tenderness, swelling, warmth, fever, lymphangitis
What are the signs/symptoms of measles?
Sore throat, dry cough, headache, conjunctivitis, lymphadenitis, fever, Koplik’s spots, maculopapular exanthem
What genus is the measles virus?
Morbillivirus
What is the difference between SSSS and TEN?
In SSSS, the split in skin tissue occurs within the epidermis; in TEN, it occurs between the dermis and epidermis
How are staphylococcus species distinguished from streptococcus species?
Catalase test (staphylo produces it, strepto does not)
What are the most common causative agents of neonatal eye infection?
Neisseria gonorrhoeae or Chlamydia trachomatis
What is Impetigo?
A superficial bacterial infection that causes the skin to flake or peel off
What are the main virulence factors of MRSA?
Production of coagulase and hyaluronidase, as well as other enzymes
What is leishmaniasis?
A protozoan infection caused by Leishmania tropica (cutaneous; skin only) or Leishmania brazilensis (mucocutaneous; skin and mucous membranes)
In addition to MRSA and Impetigo, what other skin infections are caused by S. aureus?
Folliculitis, furuncles, carbuncles, necrotizing fasciitis
What is the main sign of cutaneous anthrax?
A papule that becomes increasingly necrotic, eventually rupturing to form a black eschar
In addition to Impetigo, what other skin infections are caused by S. pyogenes?
Necrotizing fasciitis, erysipelas
How are tinea conditions transmitted?
Direct and indirect contact
What is ProQuad?
A multipathogen vaccine that vaccinates against measles, mumps, rubella, and varicella
What non-skin conditions are caused by S. pyogenes?
Streptococcal pharyngitis, scarlet fever, pneumonia, puerperal fever, rheumatic fever, bloodstream infections
What are dermatophytes?
A group of fungi that infect the skin and other components of the integument
What are the signs/symptoms of Roseola?
Maculopapular rash, high fever, possible seizures
Which group of viruses is responsible for HFMD?
Enteroviruses, usually the Coxsackie virus
What are the signs/symptoms of Fifth Disease?
Slapped-cheek appearance, blotchy rash on rest of body, low-grade fever
How is S. aureus distinguished from other staphylococcus species?
Coagulase test (only S. aureus produces it)
What treatment is prescribed for River Blindness?
Ivermectin
What word is found in all of the conditions caused by dermatophytes?
Tinea
What is the integument?
The outer surfaces of the body, including the skin, hair, nails, sweat glands, and oil glands
What are flat warts?
Smooth, skin-colored lesions
What are the signs/symptoms of a MRSA infection?
Raised, red, tender, localized lesions, often containing pus and hot to the touch; fever
What type of virus causes mollscum contagiosum?
An enveloped, double-stranded DNA poxvirus
What symptoms occur when HHV-6 is reactivated?
Mononucleosis-like or hepatitis-like symptoms
What category does S. pyogenes fall into in the CDC Antibiotic Resistance Report?
Concerning Threat
What are common/seed warts?
Painless, elevated, rough growths
What is the causative agent of gas gangrene?
Clostridium perfringens
What is the treatment for impetigo?
Antibiotics that target both S. aureus and S. pyogenes (typically Mupirocin)
What is superficial mycosis/tinea versicolor?
A cosmetic infection caused by the Malassezia yeast genus; interferes with pigment production by melanocytes
How is Rubella diagnosed?
ELISA testing, Latex-Agglutination card
What are the causative agents of impetigo?
Staphylococcus aureus and/or Streptococcus pyogenes
What causes chickenpox?
Human Herpesvirus 3 (also called Varicella virus or Varicella-Zoster virus)
What are the virulence factors of C. perfringens?
Already present dead/damaged tissue, anaerobic environment, production of several exotoxins (including alpha toxin, the most potent)
What is gas gangrene/clostridial myonecrosis?
Clostridial infection of soft tissue or wound
What is River Blindness?
A chronic helminth infection caused by Onchocerca volvulus worms
How is impetigo typically diagnosed?
By visual inspection
How is leishmaniasis transmitted?
Via female sand flies
How are tinea conditions diagnosed?
Microscopic examination and culturing
What is the main antibiotic used to treat anthrax?
Ciprofloxacin
What are the effects of congenital rubella?
Induced miscarriage or permanent birth defects
How is chickenpox spread?
Exposure to respiratory droplets and the fluid of chickenpox/shingles lesions
What is the cornea?
The dome-shaped, central portion of the eye
What drug is used to treat smallpox?
Cidofovir
What are the major distinguishing characteristics of smallpox lesions?
Indentation in the middle of the pustules; lesions feel as if they contain a BB pellet
What type of virus is Rubivirus?
Single-stranded RNA virus with a loose lipid envelope
What are the causative agents of ringworm infections?
39 different species within the genera Trichophyton, Microsporum, and Epidermophyton
What are the initial signs/symptoms of smallpox?
Fever, malaise, rash
When are those with chickenpox the most infectious?
1-2 days prior to the development of the rash
What are the most common causes of cellulitis?
S. aureus and S. pyogenes
How is impetigo transmitted?
Direct contact, indirect contact via fomites and mechanical vectors
What are the steps of progression for the smallpox rash?
Macular to papular to vesicular to pustular
How is HFMD transmitted?
Via direct contact with bodily secretions
What is a macule?
Flat, well-demarcated lesion typically indicated by a color change
What are bullous lesions?
Lesions caused by exfoliative toxins A and B in SSSS; the legions begin as red regions, take on the appearance of wrinkled tissue paper, and then become fluid filled blisters
How is Fifth Disease diagnosed?
Clinical presentation, IgM testing to rule out Rubella
Why is Rubella so damaging to fetuses?
It has the ability to stop mitosis and induce apoptosis
How can gas gangrene be prevented?
Cleansing/surgical repair of wounds and infections; debridement of dead/diseased tissue
How is MRSA treated?
Drainage of pus; antibiotic treatment consisting of Vancomycin and multiple other drugs
What is cellulitis?
A condition caused by fast-spreading infection in the dermis and subcutaneous tissues following the introduction of bacteria or fungi
What is the causative agent of smallpox?
An enveloped DNA orthopoxvirus called the variola virus
Which virus has the ability to cause host cells to form syncytia?
Measles virus
What are the two clinical forms of Rubella?
Postnatal rubella and congenital rubella
What is the most serious complication of measles?
Subacute Sclerosing Pan-encephalitis (SSPE)
What are plantar warts?
Deep, painful papillomas caused by HPV-1
How is Fifth Disease transmitted?
Respiratory droplets, direct contact
What are the initial signs/symptoms of Hand, Foot, and Mouth Disease?
Fever, sore throat, malaise, rash that begins inside the mouth
How is measles diagnosed?
Clinical presentation and indirect ELISA testing
What are the most common causative agents of bacterial conjunctivitis?
Staphylococcus aureus or Streptococcus pneumoniae
What is the main virulence factor of leishmaniasis?
Ability to multiply within macrophages
What is cutaneous anthrax?
The most common and least dangerous anthrax infection; occurs when endospores enter the skin
What are the characteristics of C. perfringens?
Gram-positive, endospore-forming bacterium, anaerobic
What is immune privilege?
The reduction of immune response in certain areas of the body that reduces potential damage to tissues that would normally be caused by an inflammatory response
Which viruses typically cause warts?
Human papillomaviruses
What are the two forms of gas gangrene?
Anaerobic cellulitis and true myonecrosis
How is SSSS diagnosed?
Histological examination
What category does MRSA fall under in the CDC Antibiotic Resistance Report?
Serious Threat
How is gas gangrene treated?
Oxygen therapy, surgical removal, antibiotic treatment
What are the characteristics of molluscum contagiosum lesions?
Smooth, waxy nodules; may be indented in middle; contain a milky fluid
What is a vesicle?
Elevated lesion with clear fluid
How is smallpox spread?
Through droplet transmission and fomites
What is toxic epidermal necrolysis?
A skin condition caused by a reaction to antibiotics, barbiturates, and other drugs
What are the virulence factors of impetigo caused by S. aureus?
Exfoliative toxins A and B, coagulase
What is a pustule?
Small, elevated lesion filled with purulent fluid (pus)
What is the causative agent of Fifth Disease?
Parvovirus B19
What are the two principle forms of smallpox?
Variola minor and Variola major
What classification has the variola virus been assigned by the CIA?
Class A Bioterrorism Agent
What is Staphylococcal Scalded Skin Syndrome?
A dermolytic condition caused by S. aureus
What is the most important virulence factor of HHV3?
Its ability to remain latent in the ganglia
What type of virus is the measles virus?
Single-stranded, enveloped RNA
What is Shingrix?
The vaccine that protects against shingles
What is the more precise name for Fifth Disease?
Erythema infectiosum
What is the more technical term for a wart?
A papilloma
What are the characteristics of an impetigo lesion?
Peeling skin, crusty and flaking scabs, honey-colored crusts
What is another name for Rubella?
German measles
What is ocular trachoma?
Chronic Chlamydia trachomatis infection of the epithelial cells of the eye
How is measles spread?
Direct contact with respiratory droplets
What is a purpura?
Reddish-purple coloration due to blood in small areas of tissue
What is lymphangitis?
Red lines leading away from an area of cellulitis
What are the characteristics of Staphylococcus aureus?
Gram-positive, coccus, grows in grape-like clusters, non-motile
How is conjunctivitis treated?
Erythromycin or other antibiotics
What are the most common causative agents of viral conjunctivitis?
Adenoviruses
What is another name for measles?
Rubeola
What family is the measles virus?
Paramyxovirus
What is the order of progression for chickenpox lesions?
Macules to papules to vesicles
How does MRSA enter the skin to cause infection?
Through injury, shaving, or abrading
