Clinical features of ESBL-producing E. coli responsible for bloodstream infections in French patients and molecular characterization of isolates

Abstract

Introduction: We conducted an annually bloodstream infection (BSI) survey into hospitals overlapping the Centre France region (2.6 million). Since 2005, the incidence of BSIs associated with ESBL-producing E. coli (ESBLEc) increased. Objectives: To improve the understanding of the pathway and the determination of the risk factors of ESBLEc-BSIs. Methods: For each BSI, were reported patient age, sex, recent hospitalization, living in nursing home, recent antibiotherapy, urinary catheterization, BSI source, death within 7days of diagnosis. BSI isolates were studied: antimicrobial susceptibility, determination of molecular mechanism associated with ESBL-production, genetic diversity of ESBLEc (MLST). Results: During the survey (474,953 PDs), 443 E. coli BSI were identified, including 31 ESBLEc (7.0%; 30/31 CTX-M). Incidence of community acquired(CA)- and healthcare associated(HCA)-BSI were 0.47/100,000 and 0.040/1,000 PDs, respectively. Major findings: For ESBLEc-CA-BSIs, male/female ratio was 1.4, median age 80, urinary BSI source in 50% of cases, recent antibiotherapy in 33 %. Most ESBLEc were resistant to fluoroquinolones (67%), SXT/TMP (67%). High genetic diversity (8 STs including 4 ST131). For ESBLEc-HCA-BSI, male/female ratio was 0.9, median age 75, urinary BSI source in 63% of cases (recent catheterization in 1/2), recent antibiotherapy in 58%. Most ESBLEC were resistant to fluoroquinolones (79%), SXT/TMP (63%). Low genetic diversity (9 STs including 7 ST131). Among BSI, ESBLEc-BSI were associated with healthcare (p=0.004), long-stay unit (p=0.018), recent antibiotherapy (p=0.002). ESBLEc were associated with resistance to fluoroquinolones, SXT/TMP and genta./tobramycine (p<0.001). Among ESBLEc-BSI, clinical determinants and BSI characteristics similar whatever the clonal group excepted for ST131 associated with long-stay unit (p=0.042). Among ST131-BSI, clinical determinants and BSI characteristics similar for ESBLEc and non ESBLEc excepted median age higher in ESBLEc (80/67). Conclusion: Recent antibiotherapy (and easy spread into long-stay units for ST131): likely the major risk factor for ESBLEc BSI.