Related Experiment Video

Updated: Mar 26, 2026

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus
10:39

Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus

Published on: March 10, 2017

17.5K

Transfer of the methicillin resistance genomic island among staphylococci by conjugation

M D Ray1,2, S Boundy1, G L Archer1,2

  • 1Department of Internal Medicine, Virginia Commonwealth University School of Medicine, 1101 East Marshall St., Richmond, VA, 23298, USA.

Molecular Microbiology
|January 30, 2016
PubMed

Insights

Researchers discovered how the staphylococcal cassette chromosome mec (SCCmec) transfers between bacteria. This finding explains the environmental spread of methicillin resistance in Staphylococcus aureus infections.

Area of Science:

  • Microbiology
  • Genetics
  • Molecular Biology

Background:

  • Methicillin resistance in Staphylococcus aureus (S. aureus) poses a significant clinical challenge.
  • The mecA gene, responsible for methicillin resistance, resides on the staphylococcal cassette chromosome mec (SCCmec), a mobile genetic element.
  • The mechanism for SCCmec transfer, despite its designation as mobile, remained undefined.

Purpose of the Study:

  • To elucidate the mechanism of staphylococcal cassette chromosome mec (SCCmec) transfer.
  • To demonstrate the capture and conjugative transfer of excised SCCmec.
  • To identify the genetic elements involved in SCCmec capture and transfer.

Main Methods:

  • Conjugative transfer experiments using filter-mating.
  • Construction of a novel plasmid, pRM27 (pGO400::SCCmec), carrying the excised SCCmec.
  • DNA sequencing to analyze the capture and integration sites of SCCmec.

Main Results:

  • Demonstrated the capture of excised SCCmec onto a conjugative plasmid (pGO400).
  • Showed successful conjugative transfer of the SCCmec-carrying plasmid (pRM27) into both homologous and heterologous S. aureus and S. epidermidis recipients.
  • Identified IS257/431 elements as mediators of recombination between SCCmec and the conjugative plasmid, enabling its capture.
  • Confirmed site-specific chromosomal integration of the transferred SCCmec in recipient strains.

Conclusions:

  • Described a novel mechanism for the capture and conjugative transfer of genomic islands like SCCmec via IS-mediated recombination.
  • Provided insight into how methicillin resistance can be environmentally disseminated through bacterial conjugation.
  • Established a means by which SCCmec can be transferred between different bacterial species, including S. aureus and S. epidermidis.

More Related Videos

Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation10:41

Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation

Published on: January 4, 2017

14.5K
Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)08:21

Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)

Published on: March 16, 2012

16.2K

Related Concept Videos

Mechanism of Conjugation01:19

Mechanism of Conjugation

Bacterial conjugation is a mechanism of horizontal gene transfer that enables the exchange of genetic material between bacterial cells through direct contact. This process is facilitated by a donor cell carrying a conjugative plasmid, which encodes genes necessary for pilus formation, DNA replication, and transfer. The conjugative plasmid plays a central role in initiating and executing the transfer of genetic material.The tra region of the conjugative plasmid encodes proteins responsible for...
1.4K
Conjugation01:19

Conjugation

Conjugation is a form of horizontal gene transfer that primarily occurs in bacteria and some archaea, promoting genetic diversity and adaptation. Bacteria can acquire resistance genes through conjugative plasmids, allowing them to survive antibiotic treatments that would otherwise be lethal. This process involves direct contact between cells through specialized structures such as the sex pilus and is mediated by conjugative plasmids, including the F (fertility) factor.Conjugation requires...
2.8K
Transduction01:16

Transduction

Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome...
2.6K
Bacterial Transformation01:33

Bacterial Transformation

In 1928, bacteriologist Frederick Griffith worked on a vaccine for pneumonia, which is caused by Streptococcus pneumoniae bacteria. Griffith studied two pneumonia strains in mice: one pathogenic and one non-pathogenic. Only the pathogenic strain killed host mice.
Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...
62.8K
Bacterial Transformation01:33

Bacterial Transformation

14.2K
Transformation01:26

Transformation

Microbial communities are dynamic environments where cell lysis releases free DNA into the surroundings. Other cells can take up this extracellular DNA through a process known as transformation.When a cell incorporates this foreign DNA into its genome, resulting in genetic modification, the process is known as transformation. Cells capable of this process are termed competent. Competence can be natural, as observed in certain bacteria and archaea, or artificially induced in the...
1.3K