Genotypic characterization of gentamicin and cephalosporin resistant Escherichia coli isolates from blood cultures in a Norwegian university hospital 2011–2015
- Open Access
- 01-12-2017
- Research
Published in:
- Authors
- Øyvind Andreas Fladberg
- Silje Bakken Jørgensen
- Hege Vangstein Aamot
- Published in
- Antimicrobial Resistance & Infection Control | Issue 1/2017
Abstract
Background
Cephalosporin resistance in clinical E. coli isolates is increasing internationally. The increase has been caused by virulent and often multidrug-resistant clones, especially the extended spectrum β-lactamase (ESBL) producing E. coli clone O25b-ST131.
Methods
In Norway, recommended empirical treatment of sepsis consists of gentamicin and penicillin combined, or a broad-spectrum cephalosporin. To investigate if increased gentamicin and cephalosporins resistance rates in our hospital could be caused by specific clones, we conducted a retrospective study on E. coli blood culture isolates from 2011 through 2015. All E. coli isolates non-susceptible to gentamicin and/or third-generation cephalosporins were genotyped using multiple-locus variable-number of tandem repeat analysis (MLVA) and compared with antibiotic susceptible isolates. The frequency of the most common genes causing ESBL production (bla CTX-M, bla ampC) was examined by Real-Time PCR.
Results
A total of 158 cephalosporin and/or gentamicin resistant and 97 control isolates were differentiated into 126 unique MLVA types. Of these, 31% of the isolates belonged to a major MLVA cluster consisting of 41% of the gentamicin resistant and 35% of the cephalosporin resistant isolates. The majority (65/80 isolates) of this MLVA cluster contained MLVA types associated with the E. coli O25b-ST131 clone. Genes encoding CTX-M enzyme phylogroups 1 and 9 occurred in 65% and 19% of cephalosporin resistant isolates, respectively, whereas bla ampC-CIT was identified in 3%.
Conclusion
No local E. coli bacteraemia clone was identified. Antibiotic resistance was dispersed over a variety of genotypes. However, association with the international E. coli O25b-ST131 clone was frequent and may be an important driver behind increased resistance rates. Monitoring and preventing dissemination of these resistant clones are important for continued optimal treatment.
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- Title
- Genotypic characterization of gentamicin and cephalosporin resistant Escherichia coli isolates from blood cultures in a Norwegian university hospital 2011–2015
- Authors
-
Øyvind Andreas Fladberg
Silje Bakken Jørgensen
Hege Vangstein Aamot
- Publication date
- 01-12-2017
- Publisher
- BioMed Central
- Published in
-
Antimicrobial Resistance & Infection Control / Issue 1/2017
Electronic ISSN: 2047-2994 - DOI
- https://doi.org/10.1186/s13756-017-0280-2
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