P0224Molecular characterisation of extended-spectrum β-lactamase-producing Escherichia coli isolated from lower respiratory tract samples between 2002 and 2019 in the central Slovenia region

03. Bacterial susceptibility & resistance

03b. Resistance surveillance & epidemiology: Gram-negatives

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P1-0198 from the Slovenian Research Agency

K. Hrovat ¹, K. Molan ², K. Seme ³, J. Ambrožič Avguštin ¹.

¹Department of Biology, Biotechnical Faculty, University of Ljubljana - Ljubljana (Slovenia), ²Department of Microbiology, Biotechnical Faculty, University of Ljubljana - Ljubljana (Slovenia), ³Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana - Ljubljana (Slovenia)

Background

The global spread of antimicrobial-resistant bacteria is emerging as one of the most serious health problems. Most concerning are infections caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC). The aim of our retrospective study was to evaluate the prevalence and molecular characteristics of ESBL-EC isolated from lower respiratory tract (LRT) samples collected over an 18-year period in selected Slovenian hospitals.

Methods

All isolates were identified by MALDI-TOF and phenotypically confirmed as ESBLs by a disk diffusion assay. Using a PCR approach, 487 non-repetitive isolates were assigned to phylogroups, sequence type groups, and clonal groups. Isolates were also screened for virulence-associated (VAGs) and antimicrobial resistance genes.

Results

The prevalence of ESBL-EC isolates from LRT in a large university hospital was low (1.4%) in 2005 and increased to 10.8% by 2019. The resistance profile of 487 ESBL-EC isolates showed a high frequency of group 1 bla_CTX-M (77.4%), bla_TEM (54.4%), and aac(6')-Ib-cr (52%) and a low proportion of bla_SHV and qnr genes. Isolates were predominantly assigned to phylogroup B2 (73.1%), which was also significantly associated with the group ST131. ST131 group accounted for 67.6% of all isolates and had a higher number of VAGs than the non-ST131 group. The virulence profile of ST131 was consistent with that of other extraintestinal pathogenic E. coli strains and was significantly associated with ten of sixteen VAGs tested. Isolates with the same ERIC-profile were confirmed in samples from different patients, at different locations and sampling dates. Biocides are used to prevent the spread of pathogens, especially in the hospital environment. However, their excessive and incorrect use can lead to the selection of bacteria that are also cross-resistant to antibiotics. Preliminary results of our study confirm the presence of biocide resistance genes involved in tolerance to quaternary ammonium compounds, which are an important group of biocides with a wide range of applications.

Conclusions

Our results suggest that the ESBL-EC isolates from LRT do not represent a specific pathotype, but rather resemble other ExPEC isolates, and may be adapted to the hospital environment. To our knowledge, this is the first study of ESBL-EC isolated from LRT samples over a long period of time.

Conclusions

Case(s) description

Discussion

References

Keyword 1

Antimicrobial resistance (AMR)

Keyword 2

Bacteria and bacterial infections

Keyword 3

extended-spectrum β-lactamase producing-Escherichia coli

Acknowledgement of grants and fundings, word count: 30 words

This work was supported by grant P1-0198 from the Slovenian Research Agency. Katja Hrovat is a recipient of a PhD grant from the Slovenian Research Agency.

Conflicts of interest

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