The spread of multiresistant pathogens poses a serious challenge worldwide. It is well-established that the global dissemination of resistant bacteria is linked to the expansion of a few major clones in many species. Though the distinguishing features of major clone strains is the subject of thorough investigation no generally accepted mechanism accounting for their success has emerged to date. It is of utmost importance to understand the background of the global dissemination of major clone isolates. Thus, in this Research Topics we would welcome manuscripts:

- demonstrating the expansion of major clone isolates in a particular geographic areas contributing to the increase of resistance rates;
- describing the characteristic antibiotic resistance mechanisms harboured by major clone strains;
- analysing of the acquisition and/or development of novel resistance mechanisms in major clone isolates;
- investigating the fitness of major clone isolates vis-a-vis minor clone strains under various conditions;
- investigating a possible link between antibiotic consumption and the dissemination of major clone strains;
- reviewing and analysing the expansion of major clone strains worldwide or in a large geographic area.

Salient pathogens whose dissemination is overwhelmingly or partly supported by major clones are: methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, vancomycin-resistant enterococci, ESBL-producing Escherichia coli, ESBL- and/or carbapenemase-producing Klebsiella pneumoniae, multiresistant and/or carbapenemase-producing Pseudomonas aeruginosa, multiresistant Acinetobacter baumannii, Clostridium difficile, Salmonella Serotype Enteritidis, Campylobacter coli. Manuscripts on major clones of additional pathogens are also welcome.

Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.