Flashcards in Gram + Bugs Deck (61)
What are the gram + bugs?
On microscopic examination what shapes are staph ans strep?
-staph: cocci, clusters (grape shaped)
-strep: diplococci, chains
Positive Gram stain is what color? Negative?
-positive is purple
-negative is red
What are these shapes?
What are all of the staphylococcus species?
What are all of the streptococci species?
-strep pyogenes (Group A)
-strep agalactiae (Group B)
-enterococcus (Group D)
What is the difference between localized and generalized infections?
-generalized infections spread through the lymphatics, tissues, blood stream, and possible other routes.
Common Bacterial Infections
-local: cellulitis, erysipelas
-lethal: nectrotizing fasciitis (flesh eating),
myconecrosis (gas gangrene or clostridial myonecrosis),
pyomyositis (abscess from bacterial infection of skeletal muscle)
What is the coagulase test? How does it aid in differentiating gram + staph sp.?
-coagulase: converts H202 to O2 and H20, makes bubbles.
-aids in differentiation because staph aureus is the only coagulase + bacteria. When H202 added to agar it bubbles.
What are some of the different infections that staph induces throughout the body?
hematogenous spread (IV drug use, epidermidis is common staph)
impetigo (weepy, mass on the skin, honey color crust)
diarrhea (staph enterotoxins)
toxic shock syndrome*
scalded skin syndrome*
What are the common skin and soft tissue infections in the immunocompetent host? Others?
-Mastitis (infection of the breast)
-infected IV catheter sites
- muscoloskeletal: septic arthritis
What is HA-MRSA & CA-MRSA? What is each associated with? How is CA-MRSA spread?
-HA-MRSA: Healthcare associated MRSA, associated w/ invasive procedures or devices. Healthcare workers as well.
-CA-MRSA: community acquired MRSA of healthy ppl. Can begin as painful boil but suddenly explodes within 24hrs.
Spread skin to skin contact, high risk individuals are wrestlers, child care workers and people who live in crowded conditions.
What might MRSA resemble? How does it develop?
-resembles spider bite*, boil, or pimple. May quickly develop into deep painful abcesses requiring surgical draining. Sometimes go deeper into the tissue causing life-threatening infections in bones, joints, blood stream, heart valves, and lungs.
What meds do we use to treat MRSA? What are some of the alternative tx?
-bactroaban ointment in nose qd
-full body wash (rules of 3) (Hibiclens) 3x/day for 3day then 3x/week for 3weeks.
What are some of the clinical features of cellulitis?
-red, swollen, shiney, warm, NO pus, tender
What are the differences between Group A streptococci and staphylococcus aureus?
-Group A strep typically follows an unrecognized injury inflammation is diffuse, spreading along tissue planes. No area of pus.
-Staphylococcus aureus usually associated with wound or penetrating trauma, localized abcess becomes surrounded by cellulitis.
What syndromes occur in the following layers?
-subcutaneous tissue (subQ fat, nerves, arteries, veins, deep fascia)
E: erysipelas, impetigo, folliculitis, furunculs, carbuncules
D & Superficial: cellulitis
SubQ: necrotizing fascitis
Tx of Cellulitis
-Clindamycin (for sulfa allergy)
*if fever, admit to hospital and administer IV abx.
Can cephalosporins be used in the tx of cellulitis?
-NO!!! they are resistant!
What is an abcess? What is the most common bacteria in an abscess?
-when the tissue area of cellulitis turns into pus under the surface of the skin.
Whats the difference between abscess and empyema?
-empyemas are accumulations of pus in a preexisting rather than a newly formed anatomical cavity
What are some examples of deep seated infections?
hepatic abscess, splenic abscess, sub-phrenic abscess, rectal abscess
Clinical features of an abscess?
-soft center, fluid underneath
Tx of abscess?
*abx cannot penetrate site w/o being drained
-when does this happen & whats happening?
-happens when bacteria in a cellulitis or abscess start spreading quickly between the fat layer and the muscle underneath it. This is termed necrotizing fasciitis.
-infection cuts off the blood supply to the tissue above it and the tissue dies.
-bacteria may enter the bloodstream. High risk of sepsis.
Tx of necrotizing fasciitis
-cut all of the dead tissue out
-abx (min 3week) help but do not cure the infection.
-open muscle is then treated like a burn with skin grafts.
*use empiric abx to cover anaerobes, gram - bacilli, streptococci, and staph aureus
If youre not aggressive eough w/ cellulitis tx w/ abscess what things may develop? What are each of these? How do you treat these?
-Myonecrosis: Gas Gangrene, pure clostridium perfringens infection. Tx w/ Pen G, chloramphenicol, or hyperbarci chamber
-Pyomyositis: purulent bacterial infection of skeletal muscles which result in pus-filled abscess. Common in tropical area. Causes by Staph aureus. Tx: drained surgically w/ abx for 3weeks.
What are the staphylococcal toxin disorders?
-Gastroenteritis (Food poisoning)
-Toxic Shock Syndrome
-Toxic Epidermal Necrolysis (TEN)
-Staph Scalded Skin Syndrome (SSSS)
What are the clinical manifestations leading up to Toxic epidermal Necrolysis?
-often begins like allergy, erythema multiforme minor(looks like bullseye), movves to erythema major when you get mucosal membrane involvement.
-second stage is stevens johnsons syndrome w/ blistering that eventually leads to TEN.