To face the problem of antibiotic resistance, it is important to understand how bacterial strains develop competence to resist treatment. An international collaboration has identified how Staphylococcus aureus acquires resistance to a widely used antibiotic.
Researchers from Institut Pasteur and its partners have demonstrated for the first time the transmission mechanisms of resistance to methicillin, an antibiotic, in Staphylococcus aureus. This resistance is transmitted from cells that are resistant to cells susceptible to the drug by the transfer of a large chromosomal region, 50 000 base pairs long. To receive this genetic material, staphylococci naturally deploy a complex molecular machinery. This mechanism is favored by the development of bacteria as biofilms which are clumps of microorganisms. The researchers also identified genetic controls that promote biofilm formation, suggesting that targeting this step could be an approach to limit the transmission of antibiotic resistance.
Staphylococcus aureus is part of the natural skin flora. It preferentially colonizes external mucosa in 30 to 50% of the population, healthy carriers who develop no symptoms. But it is also a major human pathogen, causing diseases ranging from skin lesions (boils, impetigo, etc.) to endocarditis (inflammation of the internal structures of the heart), acute pneumonia, osteomyelitis (bone infection) or sepsis. It is the leading Gram-positive bacterium responsible for nosocomial infections (hospital acquired infections). The most dangerous strains are those that display resistance to multiple antibiotics. This is the case of MRSA, methicillin resistant Staphylococus aureus, widespread in hospitals and posing a major public health concern. Methicillin is a widely used antibiotic for the control of Staphylococcus aureus infections. The mechanisms by which Staphylococcus aureus acquire resistance were previously unknown.
This study is part of the priority scientific area Antimicrobial Resistance of the Institut Pasteur's strategic plan for 2019-2023.
Natural transformation allows transfer of SCCmec-mediated methicillin resistance in Staphylococcus aureus biofilms, Nature Communications, May 5, 2022
Mais Maree1, Le Thuy Thi Nguyen2,3, Ryosuke L. Ohniwa4,5, Masato Higashide6, Tarek Msadek4, Kazuya Morikawa5
1 - Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
2 - Human Biology Program, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
3 - Biotechnology Centre of Ho Chi Minh City, District 12, HCM City, Vietnam
4 - Institut Pasteur, Université Paris Cité, CNRS UMR6047, Biology of Gram-Positive Pathogens, Department of Microbiology, F-75015 Paris, France
5 - Division of Biomedical Science, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan. 6 Kotobiken Medical Laboratories, Inc., Kamiyokoba, Tsukuba, Japan.