Bloodstream Infections

What are sources of bloodstream infections?

Line source

Injection drugs

Intraabdominal

SSTI

Pneumonia or respiratory tract infections

Urinary tract

Surgical procedures

Osteomyelitis or bone infections

Describe the mortality of bloodstream infections

Mortality can be high

Describe hematogenous spread of bloodstream infections

Bacteria in blood can 'seed' or 'stick' to devices and tissue

How should blood cultures be taken?

At least 2 sets of blood cultures taken from separate peripheral sites

After how long will a blood culture be positive if bacteria are present?

Typically are positive within 24-48 hours of collection

When should blood cultures be considered?

In patients with fever and/or leukocytosis concerning for infection

When should cultures be taken in relation to antibiotics?

Cultures first, then antibiotics

Why are cultures taken before antibiotics?

This is done to increase the yield of the culture results

Which bacteria are likely to be infection when present in a blood culture?

Staphylococcus aureus

Streptococcus pneumoniae

Streptococcus pyogenes

Enterobacterales

Pseudomonas aeruginosa

Bacteroides fragilis

Candida spp.

Which bacteria might be contamination when present in a blood culture?

Coagulase negative Staphyloccocus = Staphylococcus epidermidis, S. capitis, S. hominis

Corynebacterium spp.

How long are peripheral IV catheters used for?

Very short-term (< 10 days)

How long are central venous catheters ("central lines") used for?

Short term catheters (days to weeks)

How long are peripheral inserted central catheter/line (PICC) used for?

Short term (days to weeks)

How long are long term central access lines used for?

Months to years

What are examples of long term central access catheters?

Tunneled central venous catheters

Ports

Hemodialysis catheters

What is essential in bacteremia management?

Source control

NEED to ask what the source is since patients should not have bacteria in their blood as it is a sterile site

What should be removed in bacteremia management?

Indwelling catheters/lines if possible

How should prosthetic/hardware material be evaluated in bacteremia?

For hematogenous spread of infection and potential removal

What are common sources of Gram-negative bacteremia?

Urine and intraabdominal

What patients commonly present with bacteremia?

Patients with pyelonephritis

Describe the empiric treatment of a Gram-negative bacteremia

Treatment with IV antibiotics based on prior microbiology history

Ceftriaxone, piperacillin-tazobactam, multiple other with coverage against Enterobacterales

How should targeted therapy for bacteremia be tailored?

Based on culture and susceptibility report

Decide whether to continue IV antibiotics or transition to PO antibiotics

What is the treatment duration for Gram-negative bacteremia?

Typically 7-14 days, but recent literature supports 7 days

Should blood cultures be repeated in a Gram-negative bacteremia?

NO! DO NOT repeat blood cultures

Can Gram-negative bacteremia cause infective endocarditis?

Very rare to cause infective endocarditis

List the parts of the Staphylococcus aureus bacteremia checklist

Remove lines/catheters if present

Look for source

Echocardiogram

Repeat blood cultures every 48 hours

Optimize antibiotic choice

Define duration

What is the duration of uncomplicated S. aureus bacteremia?

2 weeks from 1st negative blood culture

Define uncomplicated S. aureus bacteremia

Exclusion of endocarditis

No implanted prostheses

Follow-up blood cultures 2 days after initial set that DO NOT grow S. aureus

Defervescence within 72 hours of effective therapy

No evidence of metastatic infection

What is the duration of complicated S. aureus bacteremia?

4-6 weeks from 1st negative blood culture

Define complicated S. aureus bacteremia

Does not meet criteria for uncomplicated

What is inferior for MSSA bacteremia?

Vancomycin is INFERIOR compared to oxacillin, nafcillin, and cefazolin

What is the preferred treatment for MRSA bacteremia?

Vancomycin or daptomycin initially

Can potentially transition to linezolid PO or TMP/SMX PO

What is the preferred treatment for MSSA bacteremia?

Cefazolin or oxacillin/nafcillin initially

Can potential transition to linezolid PO, TMP/SMX PO, or cephalexin PO