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Virulence of carbapenem-resistant Escherichia coli isolated in the Arabian Peninsula

RH Al-Marzooqi, MM Al-Dhuhoorii, D Darwish, T Pal, A Sonnevend
Published in : HAMDAN MEDICAL JOURNAL ; Vol 8, No 4 (2015): Supplement Issue
DOI : 10.7707/hmj.496


Introduction: It is generally assumed that multidrug-resistant bacteria are less virulent. However, little is known about the virulence traits of carbapenem-resistant Escherichia coli .

Objectives: To reveal the distribution of virulence factors of carbapenem-resistant extraintestinal pathogenic E. coli  isolated in the Arabian Peninsula.

Materials and methods: Thirty independent carbapenem-resistant E. coli  samples were collected between 2009 and 2013 from Saudi Arabia (n =3), Kuwait (n =5), Oman (n =7) and the United Arab Emirates (UAE) (n =15). Carbapenemase production was confirmed by the carba-NP test. Genes of KPC, NDM, OXA-48-like, VIM, IMP carbapenemases, the lipopolysaccharide core types and the phylogenetic types were identified by polymerase chain reaction (PCR). Clonal relations were established by pulsed-field gel electrophoresis (PFGE) using an 80% similarity threshold. Virulence factor-encoding genes were detected by multiplex PCRs. Biofilm production was assessed in a stationary model.

Results: Of the 30 isolates, 11 produced OXA-48-like, seven NDM-1 and one VIM-4 carbapenemases, and 11 of them did not produce carbapenemases. The strains exhibited 27 different PFGE patterns, with only three pairs of strains exhibiting clustering. Although strains belonged to all four phylogenetic groups and all five core types were detected, remarkably all OXA-48-like positive isolates belonged to phylogenetic group D and carried core type R4. The virulence factor score for the carbapenemase producers did not differ from that of the carbapenemase non-producer strains. However, members of the former group were significantly more likely to carry the yersiniabactin siderophore gene (P =0.01), to possess the virulence associated K5 capsular type (P =0.02) and to produce biofilm in anaerobic conditions (P =0.02).

Conclusions: Carbapenem-resistant E. coli  strains exhibit a variety of virulence factors. Those promoting intestinal colonization, i.e. K5 capsular type, and biofilm production under anaerobic conditions show some association with carbapenemase production.


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