Name: mrsa: host adaptation and transmission
Uploaded: 2026-03-12T13:36:05.000Z
Duration: 1 min 25 s
Channel: JoVE

La resistencia a los antibióticos es la capacidad de un microbio para soportar los efectos de los antibióticos.Un patógeno comúnmente conocido, Staphylococcus aureus, ha desarrollado resistencia a la meticilina, lo que ha dado lugar a Staphylococcus aureus resistente a la meticilina, o MRSA.El MRSA causa graves infecciones de piel y tejidos blandos en humanos, lo que provoca millones de hospitalizaciones y muertes en todo el mundo cada año.Los pacientes ancianos e inmunodeprimidos son los que tienen mayor riesgo debido al uso prolongado y extensivo de antibióticos de amplio espectro.Las estrategias para combatir el MRSA incluyen el uso de fitoquímicos, terapia con fagos, nanopartículas y probióticos.Los fitoquímicos —metabolitos secundarios extraídos de las plantas— se utilizan ampliamente para inhibir el crecimiento del MRSA.Los fagos específicos de MRSA pueden reducir las poblaciones de MRSA induciendo la lisis celular.Las nanopartículas ejercen estrés liberando iones de metales pesados en las células. Altera la permeabilidad de la membrana y altera funciones celulares esenciales.Por último, algunas cepas probióticas secretan compuestos antimicrobianos que inhiben el crecimiento del MRSA.

importancia clínica de la resistencia a los antibióticos

Clinical Significance of Antibiotic Resistance

Staphylococcus aureus resistente a meticilina (MRSA) representa una amenaza crítica para la salud pública, derivada de su capacidad para resistir los antibióticos β-lactámicos debido a la adquisición del gen mecA dentro del cromosoma de casete estafilocócico mec (SCCmec). Este gen codifica la proteína de unión a la penicilina 2a (PBP2a), que afecta la eficacia de unión de la meticilina y otros lactámicos β. El MRSA ha evolucionado en linajes clonales distintos que afectan tanto a humanos como a animales, reforzando su importancia dentro del paradigma One Health.Las cepas de MRSA se clasifican en asociadas a la atención sanitaria (HA-MRSA), asociadas a la comunidad (CA-MRSA) y asociadas al ganado (LA-MRSA). Estos linajes presentan variación del complejo clonal (CC) y especificidad del huésped. Por ejemplo, el CC398—inicialmente de origen humano—ha sufrido adaptación en ganado, especialmente cerdos, lo que ha provocado su transmisión zoonótica inversa. Se han identificado múltiples CCs como CC1, CC5, CC8 y CC97 entre especies hospedadoras, lo que implica un flujo génico interespecies complejo y una adaptación ambiental.La prevalencia global del MRSA varía ampliamente. Por ejemplo, el CA-MRSA representa el 79% de los aislados en Japón, mientras que el LA-MRSA se ha detectado en hasta el 38,6% del ganado lechero malasio. La colonización por LA-MRSA en animales supone un riesgo zoonótico, especialmente para quienes están en contacto cercano, como agricultores y veterinarios. Los informes han confirmado eventos de transmisión entre mascotas y humanos, lo que pone de manifiesto la necesidad de una vigilancia integrada.La patogenicidad del MRSA está impulsada por un conjunto de factores de virulencia, incluyendo MSCRAMMs, enterotoxinas y leucocidina de Panton-Valentine (PVL). La formación de biopelículas y las modulinas fenosolubles aumentan aún más la persistencia y la evasión inmunitaria. Las islas de patogenicidad como SaPIbov y elementos genéticos móviles como el SCCmec tipo XI que albergan mecC son fundamentales para la adaptación del huésped. Además, la toxina lukMF' , altamente expresada en cepas adaptadas a bovinos, agrava la gravedad de la mastitis en el ganado lechero.Los antibióticos tradicionales, como la vancomicina y la daptomicina, siguen siendo tratamientos clave, aunque la resistencia está aumentando. Antimicrobianos novedosos como el tedizolid y la delafloxacina, junto con enfoques no antibióticos—fitoquímicos, probióticos, nanopartículas y bacteriófagos—muestran potencial. Cabe destacar que las nanopartículas de plata sintetizadas en verde y cepas probióticas de Lactobacillus y Bifidobacterium demostraron una eficacia significativa in vitro contra MRSA

Importancia clínica de la resistencia a los antibióticos

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist &#946;-lactam antibiotics ...

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clinical-significance-of-antibiotic-resistance

Education

Educación

JoVE Core

Microbiology

Microbiología

Unit

Unidad

Antimicrobial Agents

Agentes antimicrobianos

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

mrsa: host adaptation and transmission

MRSA, or methicillin-resistant Staphylococcus aureus, is a major public health threat. It resists beta-lactam antibiotics because it carries the mecA gene inside the staphylococcal cassette chromosome mec, or SCCmec. The mecA gene makes penicillin-binding protein 2a, which reduces how well methicillin and related beta-lactam drugs can bind.

MRSA has spread into separate clonal lineages that affect both humans and animals. These lineages fit the One Health idea, which links human, animal, and environmental health. MRSA is often grouped as healthcare-associated MRSA, community-associated MRSA, and livestock-associated MRSA. These groups also show different clonal complexes and host preferences.

One example is CC398. It began in humans, then adapted to livestock, especially pigs, and later spread back from animals to people. Other clonal complexes, including CC1, CC5, CC8, and CC97, have been found across host species. This pattern shows gene flow between species and adaptation to different environments.

MRSA prevalence also differs by region and host. Community-associated MRSA makes up 79% of isolates in Japan. Livestock-associated MRSA has been found in up to 38.6% of dairy cattle in Malaysia. Because LA-MRSA can colonize animals, it can also pose a zoonotic risk to people who work closely with them, such as farmers and veterinarians.

Transmission has also been reported between pets and humans. These findings show why integrated surveillance matters. MRSA pathogenicity is driven by virulence factors such as MSCRAMMs, enterotoxins, and Panton-Valentine leukocidin, or PVL. Biofilm formation and phenol-soluble modulins also help the bacteria persist and avoid immune attack.

Mobile genetic elements are important in host adaptation. SaPIbov and SCCmec type XI, which carries mecC, are examples. In bovine-adapted strains, the lukMF' toxin is strongly expressed and can worsen mastitis in dairy cattle. These features help explain how MRSA survives in different hosts and disease settings.

Treatment still relies on antibiotics such as vancomycin and daptomycin, but resistance is increasing. Newer drugs, including tedizolid and delafloxacin, may offer more options. Non-antibiotic strategies are also being studied, including phytochemicals, probiotics, nanoparticles, and bacteriophages. Green-synthesized silver nanoparticles and probiotic strains of Lactobacillus and Bifidobacterium have shown promising results against MRSA in laboratory studies.

MRSA: Host Adaptation and Transmission

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clinical significance of antibiotic resistance

MRSA, or methicillin-resistant Staphylococcus aureus, is a major public health threat. It resists beta-lactam antibiotics because it carries the mecA gene inside the staphylococcal cassette chromosome mec, or SCCmec. The mecA gene makes penicillin-binding protein 2a, which reduces how well methicillin and related beta-lactam drugs can bind. MRSA has spread into separate clonal lineages that affect both humans and animals. These lineages fit the One Health idea, which links human, animal, and...

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inhibitors-of-virion-maturation-and-assembly

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key terms and concepts

Learn how MRSA spreads between humans and animals, why it resists beta-lactam antibiotics, and what treatments and new control methods are being studied.

MRSA: Host Adaptation and Transmission | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

MRSA: Host Adaptation and Transmission

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