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Genomic Analysis of SXT/R391 Integrative Conjugative Elements From Proteus mirabilis Isolated in Brazil
Juliana L Sato1, Marina R B Fonseca1, Louise T Cerdeira1,2
1Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
Abstract:
Integrative conjugative elements (ICEs) are widespread in many bacterial species, often carrying antibiotic resistance determinants. In the present work, we screened a collection of Proteus mirabilis clinical isolates for the presence of type 1 SXT/R391 ICEs. Among the 76 isolates analyzed, 5 of them carry such elements. The complete sequences of these elements were obtained. One of the isolates carried the CMY-2 beta-lactamase gene in a transposon and is nearly identical to the element ICEPmiJpn1 previously described in Japan, and later shown to be present in other parts of the world, indicating global spread of this element. Nevertheless, the Brazilian isolate carrying ICEPmiJpn1 is not clonally related to the other lineages carrying the same element around the world. The other ICEs identified in this work do not carry known antibiotic resistance markers and are diverse in variable gene content and size, suggesting that these elements may be responsible for the acquisition of other advantageous traits by bacteria. Some sequences carried by these elements in Brazilian strains were not previously found in other SXT/R391 variants.
Insights
This study screened Proteus mirabilis clinical isolates for integrative conjugative elements (ICEs). Five isolates contained ICEs, including a globally distributed element (ICEPmiJpn1) in a Brazilian strain distinct from other lineages.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Integrative conjugative elements (ICEs) are mobile genetic elements prevalent in bacteria.
- ICEs frequently carry antibiotic resistance genes, posing a significant public health concern.
- Type 1 SXT/R391 ICEs are a well-studied group known for their mobility and cargo.
Purpose of the Study:
- To investigate the presence and characteristics of type 1 SXT/R391 ICEs in Brazilian Proteus mirabilis clinical isolates.
- To determine the genetic content of identified ICEs, particularly focusing on antibiotic resistance genes.
- To understand the diversity and evolutionary relationships of ICEs within this bacterial population.
Main Methods:
- Screening of 76 Proteus mirabilis clinical isolates for type 1 SXT/R391 ICEs.
- Whole-genome sequencing of isolates carrying ICEs to obtain complete element sequences.
- Comparative genomic analysis to identify similarities and differences with known ICEs.
Main Results:
- Five out of 76 isolates harbored type 1 SXT/R391 ICEs.
- One isolate contained an ICE nearly identical to ICEPmiJpn1, a globally distributed element carrying the CMY-2 beta-lactamase gene.
- The Brazilian ICEPmiJpn1 strain was not clonally related to other global lineages, suggesting independent acquisition or evolution.
- Other identified ICEs lacked known antibiotic resistance markers and exhibited diverse gene content, indicating potential roles in acquiring other beneficial traits.
- Novel sequences were identified in the Brazilian ICEs, not previously observed in other SXT/R391 variants.
Conclusions:
- The study confirms the presence of diverse type 1 SXT/R391 ICEs in Brazilian Proteus mirabilis.
- The global dissemination of ICEPmiJpn1 is further evidenced, alongside the emergence of distinct local lineages.
- ICEs in this context may contribute to bacterial adaptation through the acquisition of various advantageous traits beyond antibiotic resistance.
- Further research into the novel sequences found could reveal new functions and evolutionary pathways of ICEs.
