1
Q
What are the gram + bugs?
A
- staphylococcus
- streptococcus
- clostridium botulinum
- corynebacterium Diptheriae
- closstridium tetanus
- bacillus antracis
2
Q
On microscopic examination what shapes are staph ans strep?
A
- staph: cocci, clusters (grape shaped)
- strep: diplococci, chains
3
Q
Positive Gram stain is what color? Negative?
A
- positive is purple
- negative is red
4
Q
What are these shapes?
- bacillus
- cocci
- spirillum
A
- rods
- sphere
- spiral
5
Q
What are all of the staphylococcus species?
A
- staph aureus
- staph epidermidis
- staph saprophyticus
6
Q
What are all of the streptococci species?
A
- strep pyogenes (Group A)
- strep agalactiae (Group B)
- strep pneumoniae
- strep viridans
- enterococcus (Group D)
7
Q
What is the difference between localized and generalized infections?
A
-generalized infections spread through the lymphatics, tissues, blood stream, and possible other routes.
8
Q
Common Bacterial Infections
- Localized
- Lethal
A
- local: cellulitis, erysipelas
- lethal: nectrotizing fasciitis (flesh eating),
myconecrosis (gas gangrene or clostridial myonecrosis),
pyomyositis (abscess from bacterial infection of skeletal muscle)
9
Q
What is the coagulase test? How does it aid in differentiating gram + staph sp.?
A
- 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.
10
Q
What are some of the different infections that staph induces throughout the body?
A
stye
boils/carbuncles
sinusitis
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*
Food poisioning*
osteomyelitis
pneumonia
endocarditis
11
Q
What are the common skin and soft tissue infections in the immunocompetent host? Others?
A
- abcesses
- folliculitis
- Mastitis (infection of the breast)
- wound infections
- infected IV catheter sites
Others:
- bacteremia/septicemia/endocarditis
- pneumonia
- muscoloskeletal: septic arthritis
12
Q
What is HA-MRSA & CA-MRSA? What is each associated with? How is CA-MRSA spread?
A
- 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.
13
Q
What might MRSA resemble? How does it develop?
A
-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.
14
Q
What meds do we use to treat MRSA? What are some of the alternative tx?
A
- Sulfa
- Doxycycline
- Vancomycin
- alternatives:
- bactroaban ointment in nose qd
-full body wash (rules of 3) (Hibiclens) 3x/day for 3day then 3x/week for 3weeks.
15
Q
What are some of the clinical features of cellulitis?
A
-red, swollen, shiney, warm, NO pus, tender
16
Q
What are the differences between Group A streptococci and staphylococcus aureus?
A
- 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.
17
Q
What syndromes occur in the following layers?
- epiderimis
- dermis
- superficial fascia
- subcutaneous tissue (subQ fat, nerves, arteries, veins, deep fascia)
- muscle
A
E: erysipelas, impetigo, folliculitis, furunculs, carbuncules
D & Superficial: cellulitis
SubQ: necrotizing fascitis
M: myonecrosis
18
Q
Tx of Cellulitis
A
- Bactrim (DOC)
- Clindamycin (for sulfa allergy)
- Vancomycin
*if fever, admit to hospital and administer IV abx.
19
Q
Can cephalosporins be used in the tx of cellulitis?
A
-NO!!! they are resistant!
20
Q
What is an abcess? What is the most common bacteria in an abscess?
A
- when the tissue area of cellulitis turns into pus under the surface of the skin.
- staph aureus
21
Q
Whats the difference between abscess and empyema?
A
-empyemas are accumulations of pus in a preexisting rather than a newly formed anatomical cavity
22
Q
What are some examples of deep seated infections?
A
hepatic abscess, splenic abscess, sub-phrenic abscess, rectal abscess
23
Q
Clinical features of an abscess?
A
- cellulitis present?
- swollen
- soft center, fluid underneath
- painful
24
Q
Tx of abscess?
A
- I&D
- Abx
*abx cannot penetrate site w/o being drained
25
Necrotizing fasciitis
| -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.
26
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
27
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.
28
What are the staphylococcal toxin disorders?
- Gastroenteritis (Food poisoning)
- Toxic Shock Syndrome
- Toxic Epidermal Necrolysis (TEN)
- Staph Scalded Skin Syndrome (SSSS)
29
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.
30
What is Staph Scalded Skin Syndrome?
- occurs most often in who?
- aka
-epidermolytic toxins produced by staphylococci. Toxins are distributed systemically and result in dissolution of keratinocyte attachment of upper layer of epidermis.
-occurs most often in
newborns and children.
-aka: Ritter Disease
31
Staph epidermidis is responsible for what type of infections?
-nosocomial infections; device/implant associated infections--shunts, catheters, heart valves/joints, pacemaker
32
Streptococcal are subdivided into different categories, what are these?
- divided based upon their ability to lyse RBCs.
- -beta hemolysis: complete lysis
- -alpha hemolysis: partial lysis
- -gamma hemolysis: no hemolysis
33
What is Erysipelas? What is the most common bug causing this?
acute streptococcus infection of the upper dermis and superficial lymphatics of the face.
- Streptococcus pyogenes (Beta-hemolytic group A strep)
meaning. .. it induces complete hemolysis of RBC and has the A lancefield antigen.
34
How do you differentiate between cellulitis and erysipelas?
cellulitis has an ill-defined border that merge smoothly with adjacent skin; usually pinkish to reddish and can be anywhere on the body, commonly on the UE and LE.
erysipelas has an elevated and sharply demarcated border with fiery-red appearance on the face.
Both are extremely painful, may have fever associated, and leukocytosis.
35
Tx of Cellulitis and Erysipelas?
- local care: immobilization, elevation, draw lines
| - 2weeks of abx: Penicillin and Dicloxacillin
36
What is Impetigo?
-superficial lesions that break and form highly contagious crust; may be associated with insect bites, poor hygiene, and crowded living situations.
37
How do you get erysipelas?
pathogen enters through a break in the skin and eventually spreads to the dermis and subQ tissues; can remain superficial or become systemic.
38
What are the two types of impetigo?
- common bug
- what age does it occur
- how long does it last
- what does it look like
- non-bullous: most common cause is strep Group A, Staph aureus. Occurs in preschool age children, transient, and has a thick yellowish-brown crust.
- bullous: most common cause is staph aureus, occurs in all ages, persists for 2-3days, thing flat brownish crust.
bullous=blister
39
Predisoposing factors of impetigo? Complications?
- malnutrition, diabetes, immunocompromised
Complications:
- strep infection (pink eye, meningitis, endocarditis)
- scarlet fever
- urticaria
- erythema multiforme
40
Tx of Impetigoe
- no cultures usually needed
- first soak the affected area in warm water or use wet compresses to help remove overlying scabs
- Abx creams or ointments:
- -Bactroban (Mupirocin) AAA tid x5days
- -Fusidic Acid Cream AAA x7-12days
- -Retapamulon ointment BID x5days
- -consider bactrim if hx of MRSA
-AAA= apply to affected area
41
Strep Pyogenes
- aka
- common infections
- complications
-aka: group A beta hemolytic strep
Infections:
- cutaneous infections
- pharyngitis
- otitis media
- sinusitis
- pneumonia
- streptococcal Toxic shock syndrome
Complications:
- Rheumatic fever
- Glomerulonephritis
42
What is glomerulonephritis and rheumatic fever?
- G: aby-mediated Type 3 hypersensitivity, ag-aby complexes travel to the kidney and get caught up>>shred kidney. You have brown urine, puffy face, HTN, occasional heart failure usually complain of skin or throat infection 1 week ago.
- R: delayed aby-mediated disease. Disease follows pharyngitis, extensive heart valve damage (myocarditis), arthritis, chorea, fever, subcutaneous nodules, erythema marginotum
43
Group B Streptococcus
- aka
- common infections
- how is this acquired?
- who is this most common in?
- how do they present?
-beta hemolytic group B strep
- neonatal meningitis & sepsis
- pneumonia
- female genital tract during birth
- babies
- do not eat and are crabby, fever and vomiting is a real concern.
44
Streptococcus pneumoniae
- lancefield ag?
- common infections
- how to prevent
-no lancefield ag
- pneumonia
- otitis media
- sinusitis
- meningitis
-vaccination
45
How does streptococcus pneumoniae present?
-high fever, rust sputum, and shaking chills. May have pleuritic chest pain.
46
What is otitis media? What are the types? What is the most common bug? Who does this occur most commonly in?
- otitis media is a middle ear infection.
- Acute Otitis Media: bacterial infection within the middle ear cavity
- Otitis Media with effusion: presence of nonpurulent fluid within the middle ear cavity
- strep pneumonia
- occurs most commonly in the first two years of life, more common in boys
47
Etiology of Otitis Media
common bacterial pathogens achieve access through blocked eustachian tube>>air trapping>>negative pressure>>bacterial reflux>>obstructed flow>> effusion
48
signs and sx of otitis media?-
-fever, irritability, poor feeding, otalgia, otorrhea (perforated TM), signs of common cold
49
What are some PE signs of Otitis Media?
-erythemic, opaque, bulging TM w/ loss of all landmarks, decreased TM mobility.
50
Complications of Otitis media?
- hearing loss: conductive, sensoneural, mixed)
- mastoiditis
- chronic perforation of TM
- tympanosclerosis
- facial nerve paralysis
- intracranial complications
- bacterial meningitis
- epidural abscess
- brain abscess
- cholesterol granuloma "blue drum syndrome" (blood in middle ear)
51
Tx of Otitis Media
- 1st line drugs
- 2nd line drugs
-infants 2years should receive abx if dx is certain or illness severe
1st line
- Amoxicillin or Augmentin
- Auralgan (numbing drug)
2nd line:
- Cefzil (cephalosporin)- 6mo-12years
- Pediazole (erythrommycin/sulfisoxazole)
- Bactrim
52
Streptococi Viridans
- hemolysis?
- lance field ag?
- infections associated
- where is this flora common?
- alpha or gamma hemolytic
- no!
- endocarditis, bacteremia & Septic shock, dental infections.
- common in the oral andd pharyngeal flora
53
Enterococcus
- aka
- hemolysis?
- lancefield ag?
- common infections
- resistant to what?
- most commonly found?
-Group D strep
- no hemolysis
- no lancefield ag
- UTI, endocarditis, intrabdominal infection (abscesses), biliary tract infections, wound infections
- resistant to vancomycin and ampicillin
- normally found in bowel flora, likes to be in biliary tracts, gall bladder, liver, and bowel.
54
Tools for Dx of Streptococcal infections
- Culture
- ASO titer (antistreptolysin O)
- -blood test measures aby against streptolysin O, which is what strep produces.)
- Rapid group A strep test
- Gram stains
55
DOC for
- streptococcus pyogenes
- streptococcus pneumoniae
- Enterococcus
Pyogenes: PCN
Pneumoniae: azithromycin or cephalosporins
Enterococcus: ampicillin
*erythromycin if PCN allergy
56
Anthrax
- what type of bacteria?
- why is anthrax good at evading phagocytosis?
- how can it enter the body?
- common reservoir?
- gram + spore forming bacilli
- has a capsule
- ingested>>necrotic ulcer in GI
- inhaled
- cutaneous (skin abraision)
-herbivores (cattle, goats, sheep)
57
Anthrax:
- incubation period
- clinical syndromes
- 1-7days
| - cutaneous ulcer, respiratory, gastrointestinal, oropharyngeal
58
Anthrax Dx
- non-specific prodrome of flu-like sx
- possible brief interim improvement
- abrupt onset of respiratory failure and hemodynamic collapse 2-4 days after intitial sx
- may have widened mediastiunum from bleeding the lungs on CXR
- peripheral blood smear with gram + bacilli
59
Anthrax Tx & prophylaxis
- Cutaneous:cipro or doxy x60days
- Inhalation: cipro or doxy PLUS 1 or 2 other drugs (vanco, impipenem) IV and then swith to PO for total of 60days
-Prophylaxis: cipro or doxy x60days
60
Diptheria
- caused by what bacteria?
- complications
- bacterial morphology
- how to grow this guy?
- corynebacterium diphtheriae
- myocarditis and neuritis
- gram + rods,
- grow on a K+ tellurite plate
61
Diptheria sx
Tx
- sore throate, malaise, cervical lymphadenopathy, low grade fever
- gray pseudomembrane on the back of throat, careful not to touch it as that may release more exotoxins
Tx: abx: erythromycin or PCN G
for severe cases give diptheria antitoxin, monitor airway, serial ekgs and cardiac enzymes, monitor neurologic status
