Molecular and Microbiological Evaluation of Carbapenem-resistant Enterobacteriaceae (CRE) at Two Centers in Texas

CRE cause substantial morbidity and mortality. The purpose of this study was to describe the clinical, epidemiological, molecular and microbiologic characteristics of our patients with CRE. Patients with CRE strains isolated from July 2013 to July 2015 were identified at a tertiary care VA hospital and a university-affiliated hospital in San Antonio. CRE was defined as a strain with imipenem, meropenem, or doripenem MIC ≥2 μg/ml or disk diffusion zone diameter ≤22 mm (using 10 μg disks) and resistance to ceftriaxone, cefotaxime, or ceftazidime. Molecular characterization was performed for detection of β-lactamase genes in 19 isolates. A total of 25 patients were identified. Thirteen had CRE infections; the remaining were colonized. Seventeen (68%) were men and average age was 55 years. Nineteen (76%) patients were hospitalized and 57.8 % of them were readmitted within 30 days. Thirty day mortality was 20%. Sixty percent had history of multi-drug-resistant organisms. Patients had history of prior hospitalization (88%), surgery (76%) and central line (72%). Only 12% received appropriate empiric therapy. Klebsiella pneumoniae was the most common isolate (60%) followed by Escherichia coli (28%) and Enterobacter (12%). Ceftazidime–Avivactam (CAZ-AVI) susceptibility was tested in 18 isolates and they were all found to be susceptible by FDA approved breakpoints. K. pneumoniae carbapenemases (blaKPC) were identified in 10 isolates (52.6%). No oxacillinase-48-type carbapenemases (blaOXA48) or New Delhi metallo-β-lactamase (blaNDM) were detected. Prior healthcare exposures are listed in Table 1. Table 1 Table 1 CRE continues to be infrequent at South Texas but it is associated with high morbidity and mortality. Patients with CRE had frequent healthcare contact, especially acute long-term facilities, and blaKPC was the most common carbapenemase detected. All isolates were susceptible to CAZ-AVI. All authors: No reported disclosures.