Person to Person Direct Diseases

common infection sites of s. aureus

skin (SSTIs), blood (bacteremia/sepsis), bone/joint (osteomyelitis, septic arthritis), ear (otitis media), wounds (localized infections)

hemolysins (staphylococcus virulence factor)

cytolytic toxins that lyse RBCs

leukocidins (staphylococcus virulence factor)

kill WBCs —> helps bacteria evade immune system

coagulase (staphylococcus virulence factor)

forms fibrin clot around bacteria —> hides from immune system

capsule (staphylococcus virulence factor)

prevents phagocytosis by immune cells

protein A (staphylococcus virulence factor)

interferes with antibodies

catalase (staphylococcus virulence factor)

breaks down hydrogen peroxide —> helps bacterial survival

toxic shock syndrome

caused by a superantigen toxin leading to massive immune activation, widespread inflammation, and life-threatening effects

gram stain of s. aureus

gram positive bacteria in chains

STDs

infections spread through direct sexual contact (gonorrhea, syphillis)

syphilis pathogen

treponema pallidum (spirochete)

gonorrhea pathogen

neisseria gonorrhoeae (gram negative diplococcus)

how gonorrhea escapes adaptive immunity

antigenic variation (changes pili), high mutation rate, HGT —> immune system cannot recognize it —> reinfection possible

primary syphilis

painless chancre (sore) at entry site; appears 2 weeks-2 months after infection

secondary syphilis

rash and systemic spread; may enter latent phase

tertiary syphilis

long term damage to skin, bones, and nervous system; can cause blindness and disfigurement