blood infections Flashcards
define a blood stream infection (BSI)
presence of microorganisms growing in blood cultures
what is the differences in a primary and secondary BSI
primary = unknown source of infection secondary = has another infection (pneumonia, UTI, soft tissue...)
what is the appropriate empiric treatment for a gram positive BSI
empiric therapy is vancomycin
better than like linezolid= static; vanc = cidal
what is considered a community acquired BSI
occurs less than 48 hours after hospital admission without healthcare risk factors
what are healthcare risk factors for a BSI
- hospitalization in an acute care hospital in past 90 days for longer than 1 day
- resident in a nursing home or long term care facility
- dialysis
- IV home therapy
- immunosuppressive medications
- invasive device present
what are common causes of transient bacteremia
tooth brushing
biopsy
what is a common cause of intermittent bacteremia (when it goes away and comes back repeatedly)
abscess
what is a common cause of persistent/ sustained bacteremia
intravascular (endocarditis present)
what pathogens may be true pathogens or contaminants in a BSI
viridans streptococci
enterococci spp.
what species are usual contaminants (not pathogens) in a BSI
- coagulase negative staph
- bacillus
- corynebacterium
- propionibacterium acnes
what are the most frequently occurring inpatient bacteria in BSIs in order
- S. aureus
- e. choli
- enterococcis
- Coagulase negative staph
- pseudomonas
what are the most frequently occurring out patient bacteria in BSIs in order
- e. choli
- S. aureus
- enterococci
- pseudomonas
- Cooag negative staph
what organsims are more likely to disseminate in BSIs
candida and gram positive cocci are much more likely than gram negative rods
what are some host dependent factors that put people at risk for dissemination of BSIs
- advanced age and arthritis
- prosthetic material in place
- immunosuppressed state
what are some frequent sites of dissemination
- heart valves
- bone and joints
- intervertebral discs
- eyes
What should be used to treat an MSSA BSI?
nafcillin
what should be used to treat an MRSA BSI
continue vancomycin
what should be used to treat an enterococcus BSI
ampicillin (can add gentamicin for cidal activity)
what should be used to treat an streptococcus BSI
beta-lactam
what organism gets static activity from vanc and ampicillin
enterococcus
what should be used to treat an vancomycin resistant enterococcus (VRE)
daptomycin
what is the minimum duration for a gram positive BSI
2 weeks after 1st negative culture
what gram positive BSI organism may be treated for a shorter duration?
for how long?
enterococcus
7-14 days
