Use of faropenem as an indicator of carbapenemase activity in the Enterobacteriaceae.

The aim of this study was to determine the ability of a disc susceptibility test using faropenem (10 µg) to predict carbapenemase activity in Enterobacteriaceae. A collection of 166 isolates of carbapenemase-producing Enterobacteriaceae (CPE) and 82 isolates of Enterobacteriaceae that produced other ß-lactamases was compiled from diverse sources. Disc susceptibility testing was performed using the CLSI/EUCAST methodology with discs of faropenem (10 µg), temocillin (30 µg), and four carbapenems (each 10 µg). A further prospective evaluation of the faropenem disc susceptibility test was performed using 205 consecutive isolates referred to a United Kingdom reference laboratory in parallel with molecular methods for carbapenemase detection. Of 166 isolates of CPE, 99% showed growth up to the edge of a 10-µg faropenem disc compared with only 6% of other ß-lactamase producers (sensitivity, 99%; specificity, 94%). A "double zone" around 10-µg faropenem discs was frequently associated with OXA-48 producers. Of the carbapenems, the most useful agent was imipenem, where a zone diameter of ≤ 23 mm as a predictor of carbapenemase activity had a sensitivity of 99% and a specificity of 85%. The presence of no zone of inhibition around a 30-µg temocillin disc was a consistent feature of strains producing OXA-48 carbapenemase. For 205 isolates of Enterobacteriaceae referred to a United Kingdom reference laboratory, growth up to a 10-µg faropenem disc correctly identified 84 of 86 carbapenemase producers (98% sensitivity), with a specificity of 87%. Disc susceptibility testing using faropenem (10 µg) is a simple, convenient, and highly predictive screening test for carbapenemase-producing Enterobacteriaceae.

Comparison of four chromogenic culture media for carbapenemase-producing Enterobacteriaceae.

Four chromogenic media for carbapenemase-producing Enterobacteriaceae (CPE) and two selective broths were challenged with a collection of Enterobacteriaceae with well-defined ß-lactamases and 100 stool samples. With low inocula of 130 isolates of CPE, the sensitivities of the four chromogenic media were as follows: Brilliance CRE, 78%; chromID Carba, 91%; chromID ESBL, 96%; and Colorex KPC, 56%. The corresponding sensitivities of Trypticase soy broth plus ertapenem or meropenem were 78% and 47%, respectively.

Ertapenem administered as outpatient parenteral antibiotic therapy for urinary tract infections caused by extended-spectrum-beta-lactamase-producing Gram-negative organisms.

OBJECTIVES: Infections with extended-spectrum-beta-lactamase-producing organisms are an increasing public health concern. We reviewed the use of an outpatient parenteral antibiotic therapy (OPAT) programme to facilitate the early discharge from hospital of patients with ESBL-associated urinary tract infections. METHODS: A retrospective review of patients treated for urinary tract infections caused by ESBL-producing organisms through the OPAT programme at the Royal Hallamshire Hospital, Sheffield, UK over a 4 year period to January 2010 was conducted. Data on patient demographics, clinical presentation and laboratory results were collected. RESULTS: Twenty-four OPAT episodes involving 11 patients were identified. Six patients (54.5%) had an underlying urological abnormality on presentation to OPAT. All patients were treated with parenteral ertapenem. Two patients had multiple infections treated by OPAT. The mean duration of the OPAT episodes was 9.9 days (range 3-42). A total of 238 inpatient bed days were avoided, with resultant cost savings. CONCLUSIONS: Ertapenem administration through OPAT may help to decrease the costs associated with ESBL infections by reducing the number of inpatient bed days required for their successful treatment.