Bacteremia

Bacteremia definition

Presence of bacteria in the bloodstream

Bloodstream infection (BSI) definition

Clinical infection with viable organisms in blood

Transient bacteremia definition

Short-lived bacteremia after minor procedures

Examples of transient bacteremia

Teeth brushing, cellulitis, endoscopy

Most common type of bacteremia

Transient bacteremia

Intermittent bacteremia definition

Bacteremia occurring at intervals from localized infection

Causes of intermittent bacteremia

Osteomyelitis, UTI, pneumonia, intra-abdominal infection

Continuous bacteremia definition

Persistent bacteremia from intravascular source

Causes of continuous bacteremia

Suppurative thrombophlebitis, infective endocarditis

Suppurative/septic thrombophlebitis definition

development of Venous thrombosis in the presence of bacteremia

Risk factors for suppurative thrombophlebitis

IV catheters, IV drug use, severe burns

Common organisms in suppurative thrombophlebitis

S. aureus, S. pyogenes, enteric GNRs

Most common fungal cause of thrombophlebitis

Candida species

Lemierre syndrome definition

Suppurative thrombophlebitis of the jugular vein

Lemierre syndrome main organism

Fusobacterium necrophorum

Other Lemierre syndrome organisms

Streptococcus spp., Eikenella corrodens, Fusobacterium spp.

Infective endocarditis definition

Infection of endovascular surfaces of the heart

Most common site of infective endocarditis

Heart valves

General symptoms of infective endocarditis

Fever, malaise, headache, myalgia, night sweats

Physical finding in endocarditis

Janeway lesions on palms and soles

Most common organisms causing endocarditis

Gram-positive cocci (S.aureus, Streptococcus ssp., GNR)

HACEK organisms

Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella

Endocarditis risk in immunocompromised

Increased in healthcare settings

CLABSIs means

Central line-associated bloodstream infection

What are the CLABIs

Direct extension into the bloodstream, Biofilm formation on foreign material, Suppurative thrombophlebitis

Immunocompromised risk factors

Loss of immunity, central lines, mucosal barrier loss

Pediatric bloodstream infection risk group

Neonates (even if healthy)

Neonate BSI presentation

Fever or hypothermia only

Early-onset neonatal BSI

<7 days

Late-onset neonatal BSI

>30 days

pediatric bacteremia organisms

Streptococcus agalactiae (GBS), Escherichia coli, Listeria monocytogenes

Blood culture principle

Blood has no normal flora

Interpretation of positive blood culture

Always clinically significant

Best blood culture practice

Aerobic and anaerobic set

Recommended blood volume per bottle

10 mL

Blood culture collection sites

Separate peripheral sites

Timing of blood cultures

Before antibiotics

Single blood culture practice

Never acceptable

Successful recovery for microorganisms from the blood is based on

Specimen collection methods, Blood volume, Number and timing of cultures, Interpretation of results

Catheter-associated bacteremia diagnosis

Time to positivity comparison

Catheter tip culture requirement

Peripheral blood culture simultaneously

Blood volume importance

Increases sensitivity of detection

Reason bacteremia may be missed

Low organism burden

Most important blood culture factor

Volume, not timing

Blood culture contamination impact

Increased length of stay, costs and Unnecessary antibiotics

Common blood culture contaminants

CoNS, Corynebacterium spp., viridans streptococci

Primary source of contamination

Skin and oral microbiota

Prevention of contamination

Sterile technique

Automated blood culture detection

CO2 production monitoring

Blood culture monitoring frequency

Every 10 minutes

Standard blood culture incubation time

5 days

BD Bactec bottle purpose

Supports growth and antibiotic neutralization

Blood culture bottle resin function

Absorbs one dose of most antibiotics

Pediatric blood culture volume

1-3 mL acceptable, more is better

Traditional blood culture workflow

Gram stain then plate to solid media

Time to organism ID from blood culture

18-24 hours

Time to AST results

24-48 hours

Rapid blood culture diagnostics purpose

Faster identification and resistance detection

Multiplex PCR advantage

Rapid pathogen detection

NAAT advantage

Direct detection from blood

MALDI-TOF purpose

Rapid organism identification

Rapid diagnostics limitation

Cost

Parasitic bloodstream infection example

Malaria

Malaria vector

Female Anopheles mosquito

Plasmodium species

P. falciparum, vivax, ovale, malariae, knowlesi, simium

Mild malaria symptoms

Fever, headache, fatigue, GI symptoms

Severe malaria complications

Anemia, ARDS, renal failure, cerebral malaria

Thin blood smear purpose

Identify parasite species and parasitemia

Thick blood smear purpose

Detect low parasite burden

Babesia vector

Ixodes scapularis tick

Babesia risk groups

Immunocompromised and asplenic patients

Babesia blood smear finding

Ring forms inside RBCs

African trypanosomiasis vector

Tsetse fly

Trypanosoma brucei gambiense

Eastern and central Africa, chronic disease

Trypanosoma brucei rhodesiense

Eastern and southern Africa, acute disease

African sleeping sickness late symptoms

Psychosis, seizures, somnolence

Chagas disease organism

Trypanosoma cruzi

Chagas disease vector

Triatomine (kissing) bug

Acute Chagas infection features

Mild or asymptomatic

Chronic Chagas complications

Cardiac disease, GI disease

Chagas disease diagnosis

Serology only