Molecular epidemiology and antimicrobial resistance pattern of extended-spectrum--lactamase-producing Enterobacteriaceae in Glasgow, Scotland

Nitish Khanna*, John Boyes, Paul M. Lansdell, Ahmed Hamouda, Sebastian G. B. Amyes

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Objectives: To establish the molecular epidemiology and antimicrobial resistance pattern of extended-spectrum -lactamase (ESBL)-producing Enterobacteriaceae harbouring bla(CTX-M) in Glasgow, Scotland.

Methods:During a 12 week period, Enterobacteriaceae isolates obtained from urine samples were collected and susceptibility testing performed. Isolates were screened for the presence of bla(CTX-M) by multiplex PCR and selected Escherichia coli genes were subsequently sequenced. PFGE analysis was performed on selected E. coli isolates in order to identify clonal relationships.

Results:There were 155 phenotypically confirmed non-duplicate Enterobacteriaceae isolates obtained from urine samples. bla(CTX-M) was identified in 131/155 (84.5) of the ESBL-producing isolates, with CTX-M group 1 enzymes accounting for 103/131 (78.6) of these. The remaining 24 isolates carried other bla(CTX-M) types, including CTX-M group 2, CTX-M group 9 and an unidentifiable combination designated CTX-M group G2/Gx. A sample of 46/97 (47.4) CTX-M-positive E. coli isolates was chosen for PFGE and demographic information regarding the source of the isolates was collated. Eight E. coli clusters were identified by PFGE; however, they did not achieve the 85 cut-off to demonstrate clonality. Nitrofurantoin resistance was significantly greater in the E. coli isolates expressing a non-CTX-M group 1 ESBL when compared with the E. coli isolates expressing a CTX-M group 1 ESBL.

Conclusions:As seen in other British studies, bla(CTX-M) has become the predominant ESBL type in Glasgow, Scotland. The PFGE results show that four different CTX-M groups appear to be circulating in the community and within all four hospitals in the locality. There is little correlation between strain genotype and CTX-M group, thus it is unlikely that cross-infection alone is the driver. It is possible that plasmid migration of CTX-M genes within the E. coli population is occurring.

Original languageEnglish
Pages (from-to)573-577
Number of pages5
JournalJournal of Antimicrobial Chemotherapy
Issue number3
Publication statusPublished - Mar 2012


  • CTX-M
  • antibiotic resistance
  • ESBLs
  • UK
  • CTX-M-type -lactamases

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