Gram Positive Infections Flashcards
are Group B Streptococcal Infections gram positive or gram negative?
positive
Group B Streptococcal Infections
Where are these bacteria usually found?
normal vaginal flora
Group B Streptococcal Infections
why do we test pregnant women for this?
- to see if it’s present (normal vagina flora, but want to know potential for infection)
- don’t want to pass bacteria to baby during delivery
Group B Streptococcal Infections
what do we do if a pregnant women tests pos?
abx treatment for weeks prior to birth
Group B Streptococcal Infections
why do we treat pregnant women prophylactically?
can spread to baby during birth & the bacteria is much more serious in newborns.
Group B Streptococcal Infections
What infections can this lead to?
3 most common, 3 less common
Most Common: septic abortion, endometritis, peripartum infection
Less Common: cellulitis, bacteremia, endocarditis
Group B Streptococcal Infections
Treatment
Penicillin
Vancomycin
Group B Streptococcal Infections
Can lead to what in neonates?
3 not so great things
- bacteremia
- sepsis
- meningitis
Strep Viridans
Are strep viridans hemolytic?
No- they are nonhemolytic
Strep Viridans
Where are strep viridans typically found?
normal oral flora
Strep Viridans
What do strep viridans most commonly cause?
native valve endocarditis
Group D streptococci
Group D streptococci
which bacteria is group D?
Streptococcus gallolyticus
Group D streptococci
what 2 things do people who become ill from this usually have?
GI cancer or cirrhosis
Group D streptococci
what is secondary to this infection?
endocarditis
Group A Streptococcal Infection Types
4 categories
- Non-invasive Infections
- Exotoxin Mediated Disease
- Non-supportive Immune Related Sequalae
- Invasive Infections
Group A Streptococcal Infection
Example of non-invasive infection
Bullous Impetigo
covered in Derm not ID
Group A Streptococcal Infection
Example of Exotoxin mediated disease
Scarlet Fever
Group A Streptococcal Infection
Example of Non-suppurative immune related sequalae
Rheumatic Fever
Group A Streptococcal Infection
Examples of Invasive Infections
4
Cellulitis (covered in Derm not ID)
Abscess
Bacteremia
Infective Endocarditis
Scarlet Fever
AKA
strep throat
Scarlet Fever
people with this have often recently been ______
exposed to someone with strep throat
Scarlet Fever
signs
5 things
- Exudative pharyngitis
- Bright red exanthem
- Flushed face
- Circumoral pallor
- Tongue coated with enlarged red papillae
Scarlet Fever
sx
7 things
- abrupt onset of fever
- sore throat
- headache
- chills
- nausea
- myalgias
- malaise
Scarlet Fever
what causes rash to develop?
group A beta-hemolytic streptococci toxin causes rash
Scarlet Fever
Physiology of rash occuring from toxin exposure
- local production of inflammatory mediators and alteration in cutaneous cytokines
- Dilation of blood vessels leads to characteristic scarlet color
Scarlet Fever
Evolution of “Strawberry Tongue”
- Day 1/2: tongue heavily coated with white membrane through which you can see edematous red papillae protrude
- Day 3/4/5: white membrane sloughs off, revealing shiny red tongue with prominent papillae
Scarlet Fever
Rash Characteristics
- diffusely erythematous w/ find red papules (sandpaper consistency)
- greatest in groin and axillae
- blanches (touch it and it goes away, then returns when no touch)
Scarlet Fever
how could texture of rash be described?
PPP
sandpaper
Scarlet Fever
How long after onset of fever does rash occur?
12-48 hrs
Scarlet Fever
How does rash change over course of illness?
- 12 to 48 hrs: onset, appears on neck
- travels to trunk/extremities
- 2 to 5 days: fades leaving desquamation, peeling occurs
Scarlet Fever
Timeline
Untreated: fever peaks by 2nd day, afebrile by days 5-7
Treated: fever abates 12-24 hrs after abx initiation
Scarlet Fever
Dx
- primarily a clinical diagnosis
- test: rapid strep test or throat culture
Scarlet Fever
when to do culture vs rapid test?
if rapid test was negative but you still suspect strep, send off for culture.
Strep Throat
do not treat until you have ?
positive test result
Scarlet Fever
Treatment
3 options, give med, route, dosage, and duration
Treat strep pharyngitis
* Pen VK 500mg PO 2-3x daily for 10 days
* Amoxicillin (tastes better) 500 mg PO 2x daily for 10 days
* PCN G benzathine 1.2 million units IM x 1 (expensive, not readily available)
Scarlet Fever
when to use PCN shot vs amox series?
worried about non-compliance, kids refuse meds, recurrent infections (indicating non-complicance)
Acute Rheumatic Fever
Define
autoimmune inflammatory process that develops after beta-hemolytic streptococcal pharyngitis
perivascular granulomatous rxn with valvulitis
Acute Rheumatic Fever
Epidemiology
- Most common in developing countries
- 250,000 deaths worldwide/year
- Peak incidence between ages 5-15
- Predisposition to recurrence
Acute Rheumatic Fever
Complication
Rheumatic heart disease
Acute Rheumatic Fever
Molecularly mimics which other disease?
Scarlet Fever
* immune response aimed at strep antigens
* recognizes human tissue especially on endothelial cells on heart valves
Acute Rheumatic Fever
Clinical Presentation
sx onset after what?, % of people with groups of presentations
- Typically sx onset is 2-3 wks after strep throat infection
- Variable presentation
- Carditis 50-70%
- Arthritis 35-66%
- Chorea 10-30%
- SubQ nodules 0-10%
- Erythema marginatum < 6%
Acute Rheumatic Fever
what presentation are we most worried about?
it’s the most common
cardiac complications
Acute Rheumatic Fever
Diagnosing
5 things
- Troat culture
- ASO titer
- ESR
- CRP
- Echo
no specific diagnostic tests
Acute Rheumatic Fever
what does the Jones criteria help a provider determine?
when/whether to treat for strep
Acute Rheumatic Fever
Treatment
med, dosage, duration, freq
Treat group A strep infection
* Pen VK 500mg PO 2-3x daily for 10 days
* Amoxicillin (tastes better) 500 mg PO 2x daily for 10 days
* PCN G benzathine 1.2 million units IM x 1 (expensive, not readily available)
Acute Rheumatic Fever
Symptomatic Tx
1 med, 1 action
Salicylates (ex: Aspirin)
Bed rest for carditis
Acute Rheumatic Fever
Continuous abx prophylaxis for years
what med/dosage/freq
PCN G benzathine 1.2 mil units IM every 3-4 wks
Acute Rheumatic Fever
Education to provide
risk of infective endocarditis- sx watch
emphasize oral hygiene
Acute Rheumatic Fever
what percentage of people with rheumatic heart disease have a history of rheumatic fever?
60%
Acute Rheumatic Fever
Describe chronic rheumatic heart disease
- rigid and deformed valve cusps
- fusion of the commissures
- shortening and fusion of the chordae tendinae
Acute Rheumatic Fever
What can Rheumatic Fever lead to in the long term?
more specific than rheumatic heart disease
valvular stenosis and/or regurgitation
Infective Endocarditis
Describe endocarditis
inflammatory process of the valvular or endocardial surface of the heart
Infective Endocarditis
Clinical Findings
5 (1 sx, 1 condition, 1 test result, 2 signs)
- Fever
- Pre-existing organic heart lesion
- pos blood cultures
- Evidence of vegetation on ECG
- Evidence of systemic emboli
Infective Endocarditis
Microbiology
3 bacteria, 1 other
- Staphylococcus
- Strep viridans
- Enterococcus
- Fungal
Infective Endocarditis
Which gender is IE more common in?
males
Infective Endocarditis
Which bacteria is most common for IE in IV drug users?
S. aureus
> 60% of cases
Infective Endocarditis
Which valves are typically impacted in the general population?
left sided valves (mitral/bicuspid & aortic)
Infective Endocarditis
Which valves for IV drug users?
Right sided valves, especially tricuspid
Infective Endocarditis
The rate of ____ is higher for IE in IV drug users
recurrence
Infective Endocarditis
Cardiac Predispositions
6 things
- valvular heart disease
- congenital heart disease
- prosthetic valve
- history of IE
- pacemakers
- hypertrophic cardiomyopathy
Infective Endocarditis
Most Common Clinical Findings
2 (1 sx, 1 sign)
Fever (90%)
New/changed murmur (85%)
Infective Endocarditis
Additional Clinical Findings
11 sx
chills/night sweats
anorexia, wt loss
arthralgias, myalgias
malaise
dyspnea, cough, pleuritic pain
splenomegaly
Infective Endocarditis
Uncommon findings
but pathognomonic!
janeway lesions
osler nodes
roth spots
Infective Endocarditis
Janeway lesions
nontender erythematous macules on the palms and soles
Infective Endocarditis
Osler nodes
tender subQ violaceous nodules mostly on the pads of the fingers and toes, which may also occur on the thenar and hypothenar eminences
Infective Endocarditis
Roth spots
exudative, edematous hemorrhagic lesions of the retina with pale centers
Infective Endocarditis
Components of a Diagnosis
Blood cultures
ECG
CXR
Chest CT
Infective Endocarditis
use cation with what diagnostic procedure?
cardiac catheterization
Infective Endocarditis
What would an echo show?
which valves are impacted
Infective Endocarditis
What would the CXR show?
cardiac abnormalities
Infective Endocarditis
What would a chest CT show?
may show emboli
Infective Endocarditis
What criteria help determine if someone has IE?
Duke Criteria
Infective Endocarditis
Duke Criteria thresholds for dx
- 2+ major criteria
- 1 major & 3+ minor
- 5+ minor
Infective Endocarditis
Major Criteria
Duke’s (3)
- positive blood cultures
- evidence of endocardial involvement
- new or worsening regurgitation murmur
Infective Endocarditis
Minor criteria
Duke’s (6)
- predisposition
- Fever > 100.4
- Vascular phenomena
- Immunologic phenomena
- Microbiologic evidence
- Echo findings not congruent w/ major criteria
Infective Endocarditis
What would qualify a blood culture to meet major criteria?
Duke’s (3)
- typical microbe in 2 cultures
- persistently pos cultures
- single pos culture for Coxiella burnetii
Infective Endocarditis
What would qualify as evidence of endocardial involvement to meet major criteria?
Duke’s (3)
- definite vegetation
- myocardial abscess
- new partial dehiscence of prosthetic valve
Infective Endocarditis
What is included as vascular phenomena meeting minor criteria?
Duke’s (6)
- major arterial emboli
- septic pulm infarcts
- mycotic aneurysm
- intracranial hemorrhage
- conjunctival hemorrhage
- janeway lesions
Infective Endocarditis
What are immunologic phenomena that meet minor criteria?
Duke’s (4)
- glomerulonephritis
- Osler’s nodes
- Roth spots
- rheumatoid factor
Infective Endocarditis
Classifications of Endocarditis
- acute
- subacute
Infective Endocarditis
Incubation Period of acute IE
< 6 week incubation, can be very rapid course
Infective Endocarditis
Presentation and findings of acute IE
- toxic presentation (high fevers, CP, SOB, fatigue)
- rapid progression, fatal if untreated
Infective Endocarditis
most common bacteria for acute IE
s. aureus
Infective Endocarditis
Incubation Period of subacute IE
> 6 wk incubation, can be several months
Infective Endocarditis
Presentation of subacute IE
- less dramatic presentation (low grade fever, sweats, wt loss)
- gradual progression
Infective Endocarditis
Most common pathogens for subacute IE
less virulent organisms
s. viridians, enterococcus
Infective Endocarditis
are native or prosthetic valve pts at higher risk for IE?
Prosthetic valve pts more susceptible to developing IE
Infective Endocarditis
Treatment for infection only
abx
Infective Endocarditis
tx with valve destruction
surgery
Infective Endocarditis
prevention
prophylaxis abx, hygiene
Infective Endocarditis
Abx Therapy- consult who?
ID
Infective Endocarditis
Abx Therapy- duration
4-6 wks
Infective Endocarditis
Abx therapy- when to begin?
immediately while awaiting culture results
Infective Endocarditis
Abx therapy- bacteria to cover prior to receiving culture/sensitivity results?
MRSA, staph, strep, entero
Infective Endocarditis
Abx therapy- what to initially prescribe?
Vancomycin and Ceftriaxone
Infective Endocarditis
Abx therapy- when to change meds?
only if necessary, once culture results are back!
Infective Endocarditis
Abx therapy- rechecking blood
recheck blood cultures after abx started, q 48 hrs until negative
Infective Endocarditis
Abx for Streplococcus
only give med names, 4 meds
PCN G IV
Ceftriaxone IV
Vancomycin
PCN or Ceftriaxone + Gentamicin
Infective Endocarditis
Dosage/Frequency/Duration for PCN G IV when treating for Streptococcus
12-18 mil units, divided doses
Q24 hrs
4 wks
Infective Endocarditis
Dosage/duration/freq for Ceftriaxone IV when treating for Streptococcus
2g
Q24 hrs
4 wks
Infective Endocarditis
Dosage/duration/freq for Vancomycin when treating for Streptococcus
15 mg/kg
Q12 hrs
4 wks
Infective Endocarditis
Dosage/duration/freq for PCN or Ceft. + Gentamicin when treating for Streptococcus
PCN and Ceft are same as previous
Genta: 3 mg/kg, single or divided doses; Q24 hrs, 2 wks
Infective Endocarditis
PCN considerations for streptococcus
- renal pts require dose adjustment
- use ceftriaxone if pt has non-severe PCN allergy
- use vancomycin if pt has severe PCN allergy
Infective Endocarditis
Meds to use for PCN resistant Streptococcus
- Vancymycin
- PCN G IV + Gentamicin
Infective Endocarditis
Dosage/duration/freq of Vancomycin in PCN resistant Streptococcus
30 mg/kg
Q24 hrs
4-6 wks
Infective Endocarditis
Dosage/duration/freq of PCN G IV + Genatmicin in PCN resistant Streptococcus
PCN
* 18-30 mil. units, divided
* Q24 hrs
* 4-6 wks
Genta
* 3 mg/kg
* Q24 hrs
* 4-6 wks
Infective Endocarditis
Abx for Enterococcus
2 options
- PCN G or Ampicillin or Vancomycin
- Above + Gentamicin
Infective Endocarditis
Which abx is inadequate as monotreatment for Enterococcus?
PCN
Infective Endocarditis
What do you add for tx because PCN is inadequate for Enterococcus spp?
aminoglycoside (streptomycin or gentamicin)
Infective Endocarditis
Dosage/duration/freq of PCN G when used for enterococcus
note: don’t use as monotreatment!
18-30 mil units
Q24 hrs
4-6 wks
Infective Endocarditis
Dosage/duration/freq of Ampicillin for Enterococcus
2 g
Q4 hrs
4-6 wks
Infective Endocarditis
Dosage/duration/freq of vancomycin when used for Enterococcus
15 mg/kg
Q12 hrs
4-6 wks
Infective Endocarditis
Dosage/duration/freq for Gentamicin when used for Enterococcus
1 mg/kg
Q8 hrs
4-6 wks
Infective Endocarditis
Define MSSA
Methicillin-susceptible S. aureus
Infective Endocarditis
Define MRSA
Methicillin-resistant S. aureus
Infective Endocarditis
Abx for MSSA with Native Valve IE
4
- Nafcillin/Oxacillin
- Cefazolin
- Vancomycin
Infective Endocarditis
Dosage/duration/freq for Nafcillin or Oxacillin when used for MSSA
Native Valve IE
5-2 g
Q4 hrs (12g/24 hrs)
6 wks
Infective Endocarditis
Dosage/duration/freq for Cefazolin when used for MSSA
Native Valve IE
2g
Q8 hrs
6 wks
Infective Endocarditis
Dosage/duration/freq for Vanco when used for MSSA
Native Valve IE
15 mg/kg
Q12 hrs
6 wks
Infective Endocarditis
Abx for MRSA in Native Valve IE
2
- vancomycin
- daptomycin
Infective Endocarditis
Dosage/duration/freq of Vancomycin for MRSA
Native Valve IE
15 mg/kg
Q12 hrs
6 wks
Infective Endocarditis
Dosage/duration/freq for Daptomycin with MRSA
Native Valve IE
> / = 8 mg/kg
Q24 hrs
6 wks
Infective Endocarditis
If the pt has prosthetic valve IE how do you modify abx therapies?
Triple therapy
Infective Endocarditis
Which abx are added to achieve triple therapy with both MSSA and MRSA in prosthetic valve IE?
Rifampin
Gentamicin
Infective Endocarditis
Abx therapy for MSSA in Prosthetic Valve IE
- Nafcillin/Oxacillin, Ceftriaxone, or Vacno
- Rifampin
- Gentamicin
Infective Endocarditis
Dosage/duration/freq of Rifampin for MSSA or MRSA in Prosthetic Valve IE
300 mg PO
Q8 hrs
6 wks
Infective Endocarditis
Dosage/duration/freq of Gentamicin for MSSA or MRSA in Prosthetic Valve IE
1 mg/kg
Q8 hrs
2 wks
Infective Endocarditis
Do the doses/durations/freqs of Nafcillin/Oxacillin, Ceftriaxone, or Vancomycin differ from Native Valve IE to Prosthetic Valve IE?
No
Infective Endocarditis
Does the dose/duration/freq of Vanco differ from Native Valve IE to Prosthetic Valve IE?
No
Infective Endocarditis
HACEK bacteria
these are gram neg
Haemophilus spp.
Aggregatibacter actinomycetemcomitans
Cardiobacterium hominis
Eikenella corrodens
Kingella kingae
Infective Endocarditis
Abx options for HACEK IE
6 total
- Ceftriaxone
- Ampicillin
- Cipro
- Bactrim/Quinolong/Aztreonam
Infective Endocarditis
Early surgical indications
7
- acute heart failure due to valve destruction
- unresponsive to abx
- septal abcess
- sinus of valsalva involved
- recurrent IE with the same organism
- embolism despite tx
- large mobile vegetation
Infective Endocarditis
What would be a late surgery? do we prefer late surgery?
after what?
abx course completed
prefer this is pt is stable enough
Infective Endocarditis
Surgical considerations of repair vs replacement of valve?
- extent of damage
- active infection
- compliance w/ anti-coags
Infective Endocarditis
What things should be continued post op?
which meds? how long?
- abx 1-2 wks post-op
- anti-fungal 6 wks post-op
Infective Endocarditis
Risk stratification for surgery
7 things
- age
- EF < 40%
- pre-op shock
- CKD on dialysis
- Paravalvular abscess
- Dysrhythmia
- S. aureus infection
Infective Endocarditis
Prognosis
survival rate, surgery rate, recurrance rate
- almost always fatal if untreated
- ~70% survival w/ tx
- 60% require surgery
- 20-31% have recurrance
Infective Endocarditis
Bacterial IE mortality
in hospital vs 6-month
- 18-23%
- 22-27%
Infective Endocarditis
Fungal IE mortality
in hospital vs 1 yr
- 36%
- 59%
Infective Endocarditis
Overall Complications
BIG PICTURE (4)
- valve damage/destruction
- abscess
- peripheral embolization
- therapy-related complications
Infective Endocarditis
What would valve damage/destruction complication lead to?
heart failure
Infective Endocarditis
what would an abscess complication lead to?
conduction disturbance
Infective Endocarditis
What can peripheral embolization lead to?
6 things
- in myocardium, MI
- in lungs, PE
- in brain/spinal cord, stroke/paralysis
- in eyes, blindness
- in extremities, limb ischemia
- in spleen/kidney, infarct
Infective Endocarditis
Prevention
- Basic considerations of risk factors
- Basic considerations of risk of bacteremia from procedures
- Basic considerations of risk of adverse outcomes from abx
- Targeting most likely orgnaisms
Infective Endocarditis
When is prophylaxis indicated?
5 things
- hx of IE
- cardiac valve disease in transplanted heart
- unrepaired cyanotic CHD or incompleted repaired
- CHD repair using prosthetic material
- prosthetic heart valve
Infective Endocarditis
When is prophylaxis not indicated?
7 things
- hx of rheumatic fever or kawasaki disease w/out valvular dysfuntion
- acquired valvular dysfunction
- bixuspid aortic valve
- simple atrial septal defect
- mitral valve prolapse w/ regurgitation
- hypertropic cardiomyopathy
- valve repair w/out prosthetic materia
Infective Endocarditis
High risk procedures that can lead to IE
3
- dental work (gingival)
- resp tract incisions
- surgery for infected skin
Infective Endocarditis
Prophylaxis meds/doses for high risk pts undergoing high risk procedures
4
- Amoxicillin- 2g PO
- Cephalexin- 2g PO
- Clindamycin- 600mg PO
- Azithromycin- 500mg PO
Infective Endocarditis
When to dose prophylatic meds to high risk pts
60 min prior to procedure
Infective Endocarditis
Low risk procedures leading to IE
- GI/GU
- c-section
Staphylococcus Aureus
Most common infections associated w/ S. aureus
- skin/soft tissue
- osteomyelitis (60%)
- bacteremia
- endocarditis
- TSS
Staphylococcus Aureus
what % of population are carriers?
25%
Staphylococcus Aureus
Rates of ____ are high?
MRSA
Staphylococcus Aureus
Treatment of non-MRSA infections
- incision & drainage
- Cephalexin, 500mg PO, QID
Staphylococcus Aureus
Treatment of MRSA infections
- incision & drainage
- Clindamycin, 300mg PO, TID
or - Vanco, 1gm IV, Q12 hrs
Staphylococcus Aureus Toxins
What infections can S. aureus lead to?
3 things
- Scalded skin syndrome
- TSS
- Enterotoxin food poisoning
Staphylococcus Aureus Toxins
which population is scalded skin syndrome typically seen in?
children
Staphylococcus Aureus Toxins
describe TSS
quick onset febrile illness w/ diffuse macular erythematous rash and nonpurulent conjunctivitis
Staphylococcus Aureus Toxins
fatality rate of TSS
15%
Coagulase Negative Staphylococcus
most common species?
3
- epidermidis
- haemolyticus
- hominis
Coagulase Negative Staphylococcus
are commonly resistant to ____, so they are treated with _____
- beta-lactams
- vancomycin
Coagulase Negative Staphylococcus
most common type of infection?
wound infections in those with intravascular and prosthetic devices
Coagulase Negative Staphylococcus
Can cause which complications?
osteomyelitis
endocarditis
Coagulase Negative Staphylococcus
part of which flora normally?
skin flora
Enterococcus
typical species causing infection
- faecalis
- faecium
Enterococcus
typical infections
- wound infections
- UTIs
- bacteremia
- IE
Enterococcus
Treatment options
- PCN
- Vanco
- Linezolid
Enterococcus
when to use vanco rather than PCN?
- PCN allergy
- PCN resistance
Enterococcus
dosage/freq of PCN/ampicillin
A: 2g, Q4 hrs
PCN: 3-4 mil units, Q4 hrs
Enterococcus
Vancomycin dosage/freq
15 mg/kg IV, Q12 hrs
Enterococcus
what to use in vanco resistance?
Linezolid
600mg Q12 hrs
Enterococcus
what to do with VRE?
- culture sensitivity
- inpatient contact isolation
- ID consult
Enterococcus
risks of linezolid
- bone marrow suppression
- thrombocyotpenia
Pneumococcus
most common cause of?
community acquired bacterial pneumonia
Pneumococcus
what makes a patient high risk?
5 things
- old age
- multilobar disease
- hypoxemia
- bacteremia
- extrapulm complications
Pneumococcus
Dx
- sputum culture
- rapid urine antigen test for s. pneumoniae
Pneumococcus
sens/spec of rapid urine antigen test
- sens: 70-80%
- spec: 95%
Pneumococcus
complications
4
- parapneumonic effusions
- pericarditis
- endocarditis
- meningitis
Pneumococcus
Outpatient tx
first line & in PCN allergy
- Amoxicillin, 750mg PO, Q24
- Azithromycin, 500mg day 1, followed by 250mg daily for 4 days
Pneumococcus
inpatient tx
first line & PCN allergy
- PCN G, 2 mil units IV, Q4 hrs
- Vanco, 1g IV, Q12 hrs
Bacillus
most common species causing infection
B. cereus
Bacillus
which pts are most likely to become ill with this?
3 populations
- immunocomp
- IVDU
- indwelling/implanted catheters
Bacillus
most common infections
- food posioning
- bacteremia
- endocarditis
- ocular infections
Bacillus
most commonly resistant to what? so we use what?
- PCN and cephalosporins
- Vanco