Gram-Negative Bacteremia

Pseudomonal vs. Non-Pseudomonal Rx

Optimizing antibiotic therapy for patients with pseudomonal vs. non-pseudomonal Gram-negative bacteremia


“Delay in starting effective antimicrobial therapy for P. aeruginosa bacteremia tended to be associated with higher mortality.”

Kang et al. Clin Infect Dis. 2003; 37: 745-51
 

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The Challenge

Appropriate Therapy: Pseudomonal vs. Non-pseudomonal Therapy

Gram-negative bloodstream infections (BSI) are associated with high mortality rates and can be difficult to treat due to increasing resistance to antimicrobial agents, especially for Pseudomonas aeruginosa. Treatment challenges are further compounded by conventional laboratory identification methods that can take 24 to 48 hours or longer, forcing clinicians to treat patients empirically. This makes choosing the right, empiric antibiotic coverage for patients with Gram-negative BSI challenging, especially as the decision to add an anti-pseudomonal drug is based primarily on knowledge of the infecting species.

As a result of empiric antibiotic coverage, patients with Gram-negative bacteremia are either subjected to broader-than-necessary antimicrobial therapy that can lead to subsequent infections with multi-drug resistant pathogens and the risk of toxicity complications, or are undertreated, increasing the risk for adverse patient outcomes.(1)

The challenge for clinicians is to decide when to initiate or discontinue anti-pseudomonal therapy for patients with Gram-negative bacteremia.
 
 
 

The Dilemma

Conventional Identification of Gram-Negative Bacteria Takes 1-2 days
Gram Stain - GNR

  • Cannot distinguish between E. coli, K. pneumoniae, P. aeruginosa or other Gram-negative rod species from a Gram stain.

  • When to initiate or discontinue anti-pseudomonal therapy for P. aeruginosa?

  • Conventional culture and phenotypic identification can take an additional 1-2 days.
   
 

PNA FISH® Solution

90 Min. Identification and Differentiation of E. coli, K. pneumoniae and P. aeruginosa
GNR Traffic Light®

  • 90 minutes, molecular identification and differentiation of E. coli, K. pneumoniae and P. aeruginosa directly from positive blood cultures.

  • Results 1-2 days earlier than conventional methods.

  • Help clinicians improve decision of when to initiate or discontinue anti-pseudomonal therapy to improve clinical outcomes.
 
 

Clinical Considerations
Higher Mortality Associated with Treatment Delay for P. aeruginosa Bacteremia Retrospective cohort study of 136 patients with P. aeruginosa bloodstream infections looking at the influence of delay in effective antimicrobial therapy on patient outcomes. Performed at the Seoul National University Hospital (Seoul, Korea).(4)
 
 

  • Demonstrated a trend toward higher mortality with longer delay of appropriate antimicrobial therapy

  • Appropriate antimicrobial therapy reduced 30-day mortality by 36%
 
 
 

Inappropriate Antimicrobial Therapy Increases Mortality

Retrospective cohort study measuring the effect of appropriate initial antimicrobial therapy on hospital mortality for 305 patients with P. aeruginosa bloodstream infections at Barnes-Jewish Hospital (St. Louis, MO).(5)
 
 

  • Higher mortality rate (30.7%) for patients receiving inappropriate initial antimicrobial treatment

  • Inappropriate initial antimicrobial therapy increased mortality rate by 72%
 
 
 

Appropriate Initial Therapy Improves Patient Survival

Retrospective review of appropriateness of initial antimicrobial therapy, clinical infection site and relevant pathogens in 5,715 septic shock cases from 22 medical institutions in the US, Canada, and Saudi Arabia.(3)
 
   

  • Survival rates for patients with septic shock associated with a Gram-negative infection were 3.9 times higher for those receiving appropriate initial therapy
  
 
 
 
1.  Clin Infect Dis. 2008; 47:S14-20
2.  Ann Clin Micro and Antim. 2004; 3:1-8
3.  Chest. 2009;136: 1237-48
4.  Clin Infect Dis. 2003;37:745-61
5.  Antim. Agents and Chemo. 2005;49(4):1306-11