Bacterial Diseases of the Skin

Question Answer
How does tetanus infection occur? caused by spores from the soil that enter via a puncture wound (nail in foot)
What specific pathology does C. tetani cause? jaw muscles to contract intensely–common name is lockjaw–actually all musclles of the body are affected
What animal is a source of anthrax seen in the United States? How is antrax prevented? cattle are animal source in U.S.–prevvvented by vaccination and tx of cattle
How fast does M leprae grow? organisms grow slowly and may incubate for 2-10 yrs befor infected pt shows sx. organisms do not grow in culture media
What parts of the body are infected be M. leprae? infects skin and neurons
How is leprosy transmitted? by direct contact–lepromatous leprosy–resp. aerosols–mot spread easily, as spouse of pts sometimes do not contract-even after yrs of contact–grows in 9-banded armadillos–can be transmitted by them
What is the incubation period for leprosy? organisms grow extremely slow–may incubate for 2-10 yrs before infected person shows sx
How is leprosy dx and tx? dx–observation of skin lesions and loss of sensation–tx–reserved ABT dapsone or other antibacterials in the case of resistance for 2 or more yrs
What organism causes gas gangrene? C. perfringens
All people carry S. epidermidis. Where? S. epidermidis is found on the skin
What wspecies of Staphylococcus is coagulase positive? S. aureus is coagulase positive
What percentage of people in the hospital setting are carriers of staphylococcus? 30-50%
List diseases caused by S. aureus? food poisoning, nosocomial infections, impetigo, boils, desquamation or denuding in newborns, pneumonia, and osteomyelitis
List the virulence determinants and their functions common to all strains of S. aureus Protein A–cloaks bacteria with human Abs–hemolysin–lyses RBCs–leukocidin–kills WBCs–coagulase–clots blood–catalase–degrades hydrogen peroxide
How are pyogenic staphylococcal infections primarily treated? draining the pus
What does MRSA indicate? methicillin-resistant S. aureus
what should be done to prevent staphylococcal transmission in the hospital setting? staff must engage in strict hand washing and aseptic techniques
How stable to temperature is Staphylococcus aureus? neither freezing nor food-warming temps will kill bacteria Staphylococcus aureus
Enterococcus faecalis is transmitted from where to where to cause infections? normal flora from intestinal tract that causes infection when there is a gut perforation