The outcome of treating ESBL infections with carbapenems vs. non carbapenem antimicrobials.

BACKGROUND In India where the prevalence of extended spectrum beta lactamase (ESBL) producing organisms among gram negative organisms is 60-70% and Ertapenem was unavailable at the beginning of this study, exclusive use of Group 2 Carbapenems (Imipenem and Meropenem) for treatment raises issues of cost and development of resistance. Therefore the role of non-Carbapenem alternatives, chiefly Betalactam + Betalactamase inhibitors (BL-BLI) was explored in this prospective observational study at a private tertiary care teaching hospital. PATIENTS AND METHODS 522 consecutive in door patients from the period between June 2006 to March 2007and June 2008 to December 2008, who had true infections with ESBL producing organisms were enrolled in the study. Antimicrobials were prescribed or changed by the treating physicians on the basis of the nature and severity of infection, the susceptibility of the organism and the affordability of the patient. Patients who received a Carbapenem at any time during treatment were considered in the Carbapenem group. Those who never received a Carbapenem at any time during treatment were considered in the non-Carbapenem group. RESULTS Of the 522 infections, 287 were urinary tract infections, 60 were skin structure infections, 60 were bacteremias, 55 were hospital acquired pneumonias, 31 were intra-abdominal infections and 29 were other infections. There were 351 E. coli, 119 K. pneumoniae, 23 K. oxytoca, 16 Enterobacter aerogenes, 5 Kozoanae, 4 Enterobacter agglomerans, 3 Citrobacter freundi, 1 E. cloacae, 1 Enterobacterspp. and 1 Morgenella morganii isolates. Clinical outcomes were available for 486 patients. 339 patients who were in the non-Carbapenem group and who might have had less serious infections had a clinical success rate of 79.6%. 147 patients who were in the Carbapenem group and who might have had more serious infections had a clinical success rate of 85.71%. CONCLUSIONS It is possible to successfully treat at least the less serious infections due to ESBL producing gram negative organisms with non-Carbapenem antimicrobials. This will not compromise outcomes but will likely result in restricting the use of Carbapenems which may help preserve their efficacy against increasingly resistant organisms.