Clinical Score Predicts Antibiotic Sensitivity to P. aeurginosa  in Hospitalized Patients Interview with:

Dr. Tom Lodise PharmD, Professor Albany College of Health Sciences, NY

Dr. Tom Lodise

Dr. Tom Lodise PharmD, Professor
Albany College of Health Sciences, NY What is the background for this study?

Response: P. aeruginosa (PSA) is intrinsically resistant to many commercially available antibiotics and also has a remarkable capacity to develop resistance to commonly used antibiotics like carbapenems, aminoglycosides, and fluoroquinolones. The terms ‘multidrug resistant’ (MDR) and ‘pan-drug resistant’ are often used to characterize the different patterns of multiple drug resistance exhibited by PSA. Patients with MDR-PSA infections are at an increased risk for delayed receipt of appropriate antimicrobial therapy and ample studies indicated that receipt of delayed appropriate therapy results in substantial increases in morbidity, mortality, and healthcare resource utilization.

Although risk factors for these types of infections have previously been identified in the literature, this study takes identification of risk factors further, and develops two clinical risk scores to estimate the probabilities of carbapenem and extensively beta-lactam non-susceptibility among hospitalized, adult patients with PSA infections based on covariates available on clinical presentation. We focused on these two PSA non-susceptible phenotypes as they represent infections at high risk of delayed appropriate therapy due to resistance against the current commonly prescribed empiric anti-pseudomonal antibiotics. What are the main findings? 

Response: This study was conducted at Kaiser Permanente Southern California. It included members 18 years or older with an active P. aeruginosa infection who received antibiotics within two days of the index culture date.

Patients with cystic fibrosis were excluded. P. aeruginosa infections were categorized as

(1) carbapenem non-susceptible, or (2) extensively beta-lactam non-susceptible (carbapenem, ceftazidime, piperacillin-tazobactam non-susceptible).

Patients were randomly split (1:1) into training and validation datasets. What should readers take away from your report? 

Response: Two high-performing parsimonious clinical risk scores were created and internally validated to aid clinicians in appropriate treatment selection in the critical period between suspicion of P. aeruginosa infections and availability of antibiotic susceptibility results for carbapenem resistance (one model) and for extensively beta lactam resistant (non-susceptible to carbapenem, ceftazidime, and piperacillin-tazobactam). What recommendations do you have for future research as a result of this work?

Response: We developed high-performing parsimonious risk scores to aid clinicians in appropriate treatment selection in the critical period between suspicion of Pseudomonas infection and availability of antibiotic susceptibility results.

Judicious use of broad-spectrum antibiotics is a key element of stewardship efforts, and this tool can guide targeted use of protected drugs. This field of study will need continuous evaluation due to the growing threat of antimicrobial resistance. Is there anything else you would like to add?

Response: The clinical risk score was presented as a part of a “Hot Spots in P. Aeruginosa” session at ECCMID. Multi-drug resistant P. aeruginosa is one of three pathogens that WHO identified as “critical” for which new antibiotics are urgently needed. Given the predictable nature of antimicrobial resistance, it is imperative that we preserve these antibiotics for as long as possible. It is imperative that clinicians avail themselves of tools such as this risk score to better inform prescribing.

Disclosures: Consultant for Merck & Co., and Pfizer. 


ECCMID 2018 abstract:

A clinical risk score to predict the likelihood of carbapenem non-susceptible and pan-beta-lactam non-susceptibility among adult, hospitalized patients with infections due to Pseudomonas aeruginosa

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