Direct Contact Diseases Flashcards
Staphylococcus aureus: Symptoms of Toxic Shock Syndrome
Fever, rash, vomiting, diarrhea, & death
Staphylococcus aureus: How/When is TSS most commonly caused?
- Typically initiated by staph infections after surgery
Exotoxin responsible for TSS symptoms
Superantigen
Released during cell growth
Recruits large numbers of T cells to site of infection
Cause a major inflammatory response that is fatal in 70% of cases
Virulence Factors of Staphylococcus aureus
Capsule is antiphagocytic Leukocidin Toxic Shock Syndrome Toxin -1(type of toxin, what is it’s action) Staphylokinase Coagulase Hyaluronidase
Staphylococcus aureus Virulence Factor: Capsule
Capsule - Anti-phagocytic
- Adherence to foreign bodies
Protein A
Surface proteins; prevents opsonization
(detected in Staph agglutination test to diagnose infection)
Staphylococcus aureus Virulence Factor: Leukocidin
destroys WBC and causes puss formation
Staphylococcus aureus Virulence Factor: Toxic Shock Syndrome Toxin-1
Superantigen
Released during cell growth
Recruits large numbers of T cells to site of infection
Staphylococcus aureus Virulence Factor: Staphylokinase
dissolve blood clots to move further into host
Staphylococcus aureus Virulence Factor: Coagulase
makes blood clots to hide from immune system
Staphylococcus aureus Virulence Factor: Hyaluronidase
cleaves the hyaluronic acid polymer at the β-1,4 glycosidic bond
What type of agar can differentiate pathogenic & non-pathogenic strains of S. aureus?
Mannitol Salt Agar
Prevention strategies for S. aureus infections
Virtually impossible!
Identify healthcare workers who are carriers to limit HAI transmission
Practice good hygiene
Avoid contact with personal items of other
Keep wounds covered
How are MRSA and other strains of S. aureus different?
Methicilin Resistant Staph
Failure to diagnose and treat in a timely fashion can lead to tissue damage
Same virulence factors as other Staphylococci strains, just resistant to most antibiotics used to treat infections
Treponema pallidum causes what disease
Syphilis
Treponema pallidum: Morphology
spirochete, corkscrew, fimbrae through middle
Primary Syphilis Symptoms
Localized infection at site if entry
Lesion, chancre develops 2 days to 2 months later (key symptom) (potentially long incubation)
Can heal spontaneously
Secondary Syphilis Symptoms
Develops from untreated primary syphilis
Cells spread from site if infection to mucous membranes of eyes, joints, bones, or central nervous system
Rash due to hypersensitivity reaction (key symptom), swollen lymph nodes, & fever
Tertiary Syphilis Symptoms
Development of gumma (soft tissue lesion) – (key symptom)
Mild infections of skin and bones
Serious infections of cardiovascular system or central nervous system - paralysis or neurological damage
Occurs many years after primary infection
Complications of gonorrhea
Pelvic Inflammatory Disease (PID) - women
- Inflammation & scarring of uterus and fallopian tubes
- Increased risk of ectopic pregnancies & other complications
How to diagnose gonorrhea
Presence if gram-negative diplococci is diagnostic
Can gonorrhea cause congenital disease?
Perinatal gonorrhea
- infection of the eye (neonatal conjunctivitis)
- Scaring of cornea resulting in blindness
- Occurs 2-5 days after birth
Prophylactic treatment of newborns with gonorrhea
application of antibiotic (erythromycin) gel to eyes of babies at birth
Prophylactic treatment of newborns with chlamydia
Newborns could get eye infections or pneumonia
- treated with antibiotics
Clostridium difficile: How does infection/disease occur?
overwhelms norma flora
Clostridium difficile: Why is a fecal transplant an effective treatment?
inserting healthy feces will help infected feces turn healthy
Clostridium difficile: Why is it easily spread in hospital settings?
Patients are susceptible to disease
No properly cleaning between patients
Endospores can live for up to 5 months!
HIV/AIDS: How does the virus enter a cell?
Integrase - puts genome into host chromosome
Initially infects and replicates inside macrophages
CD4 & CCR5 forms docking site
- HIV envelope fuses with host cytoplasmic membrane
- required for viral nucleocapsid to be inserted into the cell
HIV/AIDS: What cell type is most affected?
- HIV virions released from macrophages infect & replicate Th cells
- Th cells that produce HIV no longer divide and numbers eventually diminish
Good prognosis for a patient with HIV?
Low numbers of HIV virions & high numbers of CD4+ cells
Dormant HIV
Infection does not progress immediately to killing immune cells
HIV exists as a provirus in the host chromosome
HIV genome replicates as host cell DNA replicates
Cell will show now outward sign of infection
HIV can remain dormant for long periods
Eventually full replication will resume producing virions that are released from the cell capable of infecting new cells
When do opportunistic infections develop in someone with active HIV/AIDS?
When CD4 cells are gone
What are the symptoms of acute hepatitis?
Jaundice
dark urine
fever
fatigue
What are the symptoms of chronic hepatitis?
i. Can take decades to develop
ii. Cirrhosis - Build up of scar tissue on liver
iii. Liver failure, liver tissue dying
iv. Fluid in abdomen, weight loss, bleeding and bruising easily
What type of Hepatitis has vaccines?
Hep A - Yes HepB - Yes Hep C - No Hep D - Hep B Vaccination Hep E - NO
What does hepatitis mean?
inflammation of the liver
Does every strain of HPV cause cancer?
no
What do non-cancerous strains of HPV cause?
genital warts
For what age ranges and genders is the vaccine for HPV recommended?
i. Preteen boys and girls to start around age 11-12.
ii. Series of 3 shots given before the age of 26 for women, 21 for men
iii. Must be given within a 6 month period
