New Data Analysis Shows Antibiotic Resistance Rates Vary Substantially Among Different Enterobacteriaceae Strains in Hospital Setting

BOSTON -- A new analysis of data from Focus Technologies Surveillance Network (TSN®) Database USA indicates that resistance rates for beta-lactams and fluoroquinolones varied substantially among different Enterobacteriaceae species and with species by site of infection.  Extended-spectrum beta-lactams and fluoroquinolones are a cornerstone of therapy for serious infections caused by Enterobacteriaceae, which include infections of the lower respiratory tract and urinary tract.  Results of this analysis were presented at the annual meeting of the Infectious Diseases Society of America (IDSA). 

Because Enterobacteriaceae are among the most common and problematic infections encountered in hospitalized patients, it is important to continue to monitor resistance rates involving the key drugs used to treat the gram-negative bacilli so commonly associated with these infections, said Daniel F. Sahm, PhD, chief scientific officer of Focus Technologies.  Knowing the current state of antimicrobial resistance provides a critical resource for understanding trends that indicate each drugs antimicrobial effectiveness in terms of which drugs are, and are not, maintaining activity.  Such information also is useful for evaluating the types of drugs that likely will be needed in the future as resistance trends continue to evolve.

Study Methodology and Results 
Antimicrobial susceptibility among bacterial pathogens encountered in hospitals is constantly in a state of change.  In order to evaluate the most current status of the antibiotics most commonly used to treat hospital-based infections, Focus Technologies analyzed data collected in 2003 from The Surveillance Network (TSN) Database USA, an electronic surveillance system that collects routine susceptibility test results from approximately 300 hospital laboratories in the United States.  NCCLS (2003) breakpoints were used to interpret susceptibility or resistance. 

Susceptibility to ceftriaxone, cefepime, ceftazidime, ciprofloxacin, levofloxacin and piperacillin-tazobactam -- among the most commonly used antibiotics for serious infections caused by Enterobacteriaceae strains -- was examined for various Enterobacteriaceae species (E. coli, K. pneumoniae, E. cloacae, S. marcescens; E. aerogenes and C. freundii) isolated from lower respiratory tract and urinary tract specimen sources from individuals older than age 64 who were hospital inpatients.   

Study results showed that antibiotic resistance rates varied widely among different Enterobactreiaceae species and with species by site of infection.

These data demonstrate the changing susceptibility profiles of organisms isolated from Enterobacteriaceae infections and the need to consider the antibiotic susceptibility profiles of organisms in hospitalized patients when selecting a treatment, added Sahm.  Antibiotics such as ceftriaxone and other advanced-generation cephalosporins, along with fluoroquinolones, serve as the cornerstone of therapy for hospital-based infections. Therefore, constant surveillance of their antimicrobial activity is necessary to understand trends that will help evaluate their continued utility or ultimate demise as therapeutic choices.

This research was funded by Roche Laboratories, Inc.

Source: Focus Technologies, Inc.