Bacteremia: Interpreting GenMark ePlex® Results – VASP¶
Background¶
- When BCx turn positive, the lab reports Gram stain and GenMark ePlex® results to help guide empiric therapy, while awaiting further species identification and susceptibilities.
Management¶
-
Start empiric antibiotic therapy (based on clinical picture and table below)
-
Consider ordering repeat BCx x2 based on organism to document clearance
- Repeat for: Staph (MRSA or MSSA), Strep lugdunensis
- If source control & no endovascular infxn, no need to repeat (most other strep and GNR’s)
-
VUMC antibiograms can be used to reference typical resistance patterns and most common organisms in blood cultures.
-
Candida in a blood culture is NEVER considered a contaminant
GRAM POSITIVE COCCI
|
|
|
---|---|---|
Staphylococcus aureus
Staphylococcus lugdunensis ID Consult REQUIRED |
mecA detected | Start vancomycin IV |
No mecA detected | Start nafcillin or cefazolin Stop empiric vancomycin IV |
|
Staphylococcus epidermidis -Often skin contaminant -Repeat cultures, start therapy if uncertain |
mecA detected | Start vancomycin IV |
No mecA detected | Start nafcillin or cefazolin Stop empiric vancomycin IV |
|
Other coagulase negative Staph -Often skin contaminant -Repeat cultures, start abx if uncertain |
Start vancomycin IV | |
Streptococcus: agalactiae, pyogenes, anginosus | Start penicillin IV or CTX IV Stop empiric vancomycin |
|
Streptococcus pneumoniae | Start ceftriaxone Stop empiric vancomycin Await PCN sensitivity data |
|
Other Streptococcus -May be contaminant |
Start ceftriaxone Stop empiric vancomycin Await PCN sensitivity data |
|
Enterococcus faecalis ID Consult REQUIRED |
vanA or vanB detected | Start daptomycin 8-10mg/kg/day IV Don’t treat w vancomycin IV Contact precautions |
No vanA or vanB | Start ampicillin Stop empiric vancomycin IV |
|
Enterococcus faecium ID Consult REQUIRED |
vanA or vanB detected | Start daptomycin 8-10mg/kg/day IV Don’t treat w vancomycin IV Contact precautions |
No vanA or vanB | Start vancomycin IV Follow-up ampicillin sensitivities |
|
Micrococcus -Often if in a single blood culture is skin contaminant |
Repeat BCx Start vancomycin IV if uncertain |
GRAM POSITIVE RODS
|
|
---|---|
Listeria monocytogenes | Start ampicillin Stop empiric vancomycin IV |
Other Gram positive rod (e.g. Bacillus cereus, Corynebacterium, Cutibacterium acnes, Lactobacillus) -Often skin contaminant -Repeat cultures, start therapy if uncertain |
Start vancomycin IV Follow-up sensitivities; some GPRs are resistant to vancomycin |
GRAM NEGATIVE RODS *Consult ID if carbapenem resistance detected*
Organism | Preliminary Recommendation |
---|---|
Acinetobacter baumannii | Start ampicillin/sulbactam |
Bacteroides fragilis | Start metronidazole If polymicrobial infection, piperacillin/tazobactam, ampicillin/sulbactam, or meropenem based on other organisms Do NOT double cover anaerobes |
Citrobacter spp. | Start/continue cefepime |
Cronobacter sakazakii | Start/continue cefepime |
Enterobacter (non-cloacae complex) | Start/continue cefepime |
Enterobacter cloacae complex | Start/continue cefepime |
Escherichia coli | Continue empiric coverage and await susceptibilities |
Fusobacterium nucleatum Fusobacterium necrophorum |
Start ampicillin/sulbactam or start/continue metronidazole |
Haemophilus influenzae | Start/continue ceftriaxone |
Klebsiella oxytoca | Continue empiric coverage and await susceptibilities |
Klebsiella pneumoniae group | Continue empiric coverage and await susceptibilities |
Morganella morganii | Start/continue cefepime |
Neisseria meningitidis | Continue empiric coverage and await susceptibilities |
Proteus spp. Proteus mirabilis |
Continue empiric coverage and await susceptibilities |
Pseudomonas aeruginosa | Start/continue cefepime or piperacillin-tazobactam |
Salmonella spp | Start/continue ceftriaxone |
Serratia spp. Serratia marcescens |
Start/continue cefepime |
Stenotrophomonas maltophilia | Start trimethoprim-sulfamethoxazole (15-20mg/kg/day divided q8h for normal renal function) |
Gram-Negative Resistance Genes | |
CTX-M Positive (ESBL) | Start meropenem Consider an Infectious Diseases consult Contact precautions (see Infection Prevention website) |
IMP Positive KPC Positive NDM Positive OXA (OXA-23 and OXA-48) Positive VIM Positive |
Carbapenemase-producing organism Obtain Infectious Disease consultation Contact precautions (see Infection Prevention website) |