Interpreting Verigene® Results

Vanderbilt Microbiology provides rapid diagnostic information on positive blood cultures with the goal of quickly tailoring therapy to provide the most potent antibiotic while limiting unnecessary toxicity.

Follow these steps to adjust antibiotic therapy based on Verigene® results and Vanderbilt antibiogram data:

  1. Locate the appropriate table below (e.g., Gram positive cocci, Gram positive rod or Gram negative rod)
  2. Specify the organism and reported resistance marker
  3. Follow preliminary recommendations as appropriate

Verigene® results should never supersede clinical judgement.

Continue to base therapy on careful history, physical and available data (e.g., allergies, renal function, etc.) and remain aware that contaminated blood cultures are reported just as any other culture.


Traditional culture data (i.e., speciation and susceptibility) will still be available in 2-3 days and remains the gold standard upon which final antibiotic recommendations should be based.

Do not hesitate to consult Infectious Diseases (or page 615-317-GERM) with questions.

GRAM POSITIVE COCCI

Organism

Resistance Marker

Preliminary Recommendation

Staphylococcus aureus

mecA

Start vancomycin IV

  • contact precautions

X

Start nafcillin or cefazolin

  • stop empiric vancomycin IV

Staphylococcus lugdunensis

 

Start vancomycin IV

Staphylococcus epidermidis

  • often skin contaminant
  • repeat cultures then start therapy if uncertain

mecA

Start vancomycin IV

X

Start nafcillin or cefazolin

  • stop empiric vancomycin IV

Other coagulase negative Staphylococcus

  • often skin contaminant
  • repeat cultures then start therapy if uncertain
 

Start vancomycin IV

Streptococcus

agalactiae

 

Start penicillin IV

  • stop empiric vancomycin

pyogenes

anginosus group

Streptococcus pneumoniae

 

Start ceftriaxone

  • stop empiric vancomycin
  • await penicillin sensitivity data

Other Streptococcus

 

Start penicillin IV

  • stop empiric vancomycin

Enterococcus faecalis

vanA

Start daptomycin

  • do not treat with vancomycin IV
  • contact precautions

vanB

X

Start ampicillin

  • stop empiric vancomycin IV

Enterococcus faecium

vanA

Start daptomycin

  • do not treat with vancomycin IV
  • contact precautions

vanB

X

Start vancomycin IV

GRAM POSITIVE ROD

Organism

Resistance Marker

Preliminary Recommendation

Listeria monocytogenes

 

Start ampicillin

  • stop empiric vancomycin IV

Other Gram positive rod

  • often skin contaminant
  • repeat cultures then start therapy if uncertain
 

Start vancomycin IV

GRAM NEGATIVE ROD

Organism

Resistance Marker

Preliminary Recommendation

Acinetobacter species

X

Start IV Gram negative coverage based on

ESBL

Start carbapenem therapy

  • consider Infectious Diseases consult
  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Citrobacter species

X

Start IV Gram negative coverage based on

ESBL

Start carbapenem therapy

  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Enterobacter species

X

Start IV Gram negative coverage based on

ESBL

Start carbapenem therapy

  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Escherichia coli

X

Start IV Gram negative coverage based on

ESBL

Start carbapenem therapy

  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Klebsiella pneumoniae or oxytoca

X

Start IV Gram negative coverage based on

ESBL

Start carbapenem therapy

  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Proteus species

X

Start IV Gram negative coverage based on

ESBL

Start carbapenem therapy

  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Pseudomonas aeruginosa

X

Start IV Gram negative coverage based on

ESBL

Start meropenem (do not start ertapenem)

  • contact precautions

carbapenem resistance

Consult Infectious Diseases

  • contact precautions

Organism

Resistance Marker

Preliminary Recommendation

Listeria monocytogenes

 

Start ampicillin

  • stop empiric vancomycin IV

Other Gram positive rod

  • often skin contaminant
  • repeat cultures then start therapy if uncertain
 

Start vancomycin IV

References

Rödel J, Karrasch M, Edel B, Stoll S, Bohnert J, Löffler B, Saupe A, Pfister W. Antibiotic treatment algorithm development based on a microarray nucleic acid assay for rapid bacterial identification and resistance determination from positive blood cultures. Diagn Microbiol Infect Dis. 2016 Mar;84(3):252-7

Suzuki H, Hitomi S, Yaguchi Y, Tamai K, Ueda A, Kamata K, Tokuda Y, Koganemaru H, Kurihara Y, Ishikawa H, Yanagisawa H, Yanagihara K. Prospective intervention study with a microarray-based, multiplexed, automated molecular diagnosis instrument (Verigene system) for the rapid diagnosis of bloodstream infections, and its impact on the clinical outcomes. J Infect Chemother. 2015 Dec;21(12):849-56.

Roshdy DG, Tran A, LeCroy N, Zeng D, Ou FS, Daniels LM, Weber DJ, Alby K, Miller MB. Impact of a rapid microarray-based assay for identification of positive blood cultures for treatment optimization for patients with streptococcal and enterococcal bacteremia. J Clin Microbiol. 2015 Apr;53(4):1411-4.

Perez KK, Olsen RJ, Musick WL, Cernoch PL, Davis JR, Peterson LE, Musser JM. Integrating rapid diagnostics and antimicrobial stewardship improves outcomes in patients with antibiotic-resistant Gram-negative bacteremia. J Infect. 2014 Sep;69(3):216-25.

Huang AM, Newton D, Kunapuli A, Gandhi TN, Washer LL, Isip J, Collins CD, Nagel JL. Impact of rapid organism identification via matrix-assisted laser desorption/ionization time-of-flight combined with antimicrobial stewardship team intervention in adult patients with bacteremia and candidemia. Clin Infect Dis. 2013 Nov;57(9):1237-45.

Sango A, McCarter YS, Johnson D, Ferreira J, Guzman N, Jankowski CA. Stewardship approach for optimizing antimicrobial therapy through use of a rapid microarray assay on blood cultures positive for Enterococcus species. J Clin Microbiol. 2013 Dec;51(12):4008-11.