Objectives: To assess the admission prevalence of  third-generation cephalosporin-resistant Enterobacterales (3GCREB) and  to assess whether risk factors vary by β-lactamase genotype.

Methods: Adult  patients were recruited within 72 h of admission to general wards of  six university hospitals in 2014 and 2015. Rectal swabs were screened  for 3GCREB and isolates were analysed phenotypically and genotypically.  Patients were questioned on potential risk factors. Multivariable  analyses were performed to identify risk factors for 3GCREB colonization  and for specific β-lactamases.

Results: Of 8753  patients screened, 828 were 3GCREB positive (9.5%). Eight hundred and  thirteen isolates were available for genotyping. CTX-M-15 was the most  common ESBL (38.0%), followed by CTX-M-1 (22.5%), CTX-M-14 (8.7%),  CTX-M-27 (7.5%) and SHV-ESBL (4.4%). AmpC was found in 11.9%.  Interestingly, 18 Escherichia coli isolates were AmpC positive, 12 of  which (67%) contained AmpC on a gene of plasmid origin [CMY (n = 10),  DHA (n = 2)]. Risk factors for 3GCREB colonization varied by genotype.  Recent antibiotic exposure and prior colonization by  antibiotic-resistant bacteria were risk factors for all β-lactamases  except CTX-M-14 and CTX-M-27. Travel outside Europe was a risk factor  for CTX-M-15 and CTX-M-27 [adjusted OR (aOR) 3.49, 95% CI 2.88-4.24 and  aOR 2.73, 95% CI 1.68-4.43]. A previous stay in a long-term care  facility was associated with CTX-M-14 (aOR 3.01, 95% CI 1.98-4.59). A  preceding hospital stay in Germany increased the risk of CTX-M-15 (aOR  1.27, 95% CI 1.14-1.41), while a prior hospital stay in other European  countries increased the risk of SHV-ESBL colonization (aOR 3.85, 95% CI  1.67-8.92).

Conclusions: The detection of  different ESBL types is associated with specific risk factor sets that  might represent distinct sources of colonization and ESBL-specific  dissemination routes.