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

Resistência a antibióticos é a capacidade de um microrganismo de suportar os efeitos dos antibióticos.Um patógeno comumente conhecido, Staphylococcus aureus, desenvolveu resistência à meticilina, resultando em Staphylococcus aureus resistente à meticilina, ou MRSA.O MRSA causa infecções graves de pele e tecidos moles em humanos, levando a milhões de hospitalizações e fatalidades no mundo todo o ano a cada ano.Idosos e pacientes imunossuprimidos estão em maior risco devido ao uso prolongado e extensivo de antibióticos de amplo espectro.Estratégias para combater o MRSA incluem o uso de fitoquímicos, terapia com fagos, nanopartículas e probióticos.Fitoquímicos — metabólitos secundários extraídos das plantas — são amplamente usados para inibir o crescimento do MRSA.Fagos específicos para MRSA podem reduzir populações de MRSA induzindo a lise celular.Nanopartículas exercem tensão ao liberar íons de metais pesados nas células. Ela altera a permeabilidade da membrana e interrompe funções celulares essenciais.Por fim, algumas cepas probióticas secretam compostos antimicrobianos que inibem o crescimento do MRSA.

significado clínico da resistência a antibióticos

Clinical Significance of Antibiotic Resistance

O Staphylococcus aureus resistente à meticilina (MRSA) apresenta uma ameaça crítica à saúde pública, decorrente de sua capacidade de resistir aos antibióticos β-lactâmicos devido à aquisição do gene mecA dentro do cromossomo cassete estafilocócico mec (SCCmec). Esse gene codifica a proteína de ligação à penicilina 2a (PBP2a), que prejudica a eficácia de ligação da meticilina e de outros β-lactâmicos. O MRSA evoluiu para linhagens clonais distintas que impactam humanos e animais, reforçando sua importância dentro do paradigma One Health.As cepas de MRSA são categorizadas em associadas à saúde (HA-MRSA), associadas à comunidade (CA-MRSA) e associadas ao gado (LA-MRSA). Essas linhagens apresentam variação do complexo clonal (CC) e especificidade de hospedeiro. Por exemplo, o CC398 — inicialmente de origem humana — passou por adaptação em animais, especialmente porcos, levando à sua transmissão zoonótica reversa. Múltiplos CCs como CC1, CC5, CC8 e CC97 foram identificados entre espécies hospedeiras, implicando fluxo gênico complexo entre espécies e adaptação ambiental.A prevalência global do MRSA varia bastante. Por exemplo, o CA-MRSA representa 79% dos isolados no Japão, enquanto o LA-MRSA foi detectado em até 38,6% do gado leiteiro malaio. A colonização de LA-MRSA em animais representa um risco zoonótico, especialmente para aqueles em contato próximo, como agricultores e veterinários. Relatórios confirmaram eventos de transmissão entre animais de estimação e humanos, destacando a necessidade de vigilância integrada.A patogenicidade do MRSA é impulsionada por um conjunto de fatores de virulência, incluindo MSCRAMMs, enterotoxinas e leucocidina de Panton-Valentine (PVL). A formação de biofilmes e as modulinas fenolsolúveis aumentam ainda mais a persistência e a evasão imune. Ilhas de patogenicidade como SaPIbov e elementos genéticos móveis como o SCCmec tipo XI, que abrigam mecC , são críticos na adaptação do hospedeiro. Além disso, a toxina lukMF' , altamente expressa em cepas adaptadas a bovinos, agrava a gravidade da mastite em bovinos leiteiros.Antibióticos tradicionais, incluindo vancomicina e daptomicina, continuam sendo tratamentos principais, embora a resistência esteja aumentando. Antimicrobianos inovadores como tedizolid e delafloxacina, juntamente com abordagens não antibióticas — fitoquímicos, probióticos, nanopartículas e bacteriófagos — mostram potencial. Notavelmente, nanopartículas de prata sintetizadas em verde e cepas probióticas de Lactobacillus e Bifidobacterium demonstraram eficácia significativa in vitro contra MRSA

Significado Clínico da Resistência a 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

JoVE Core

Microbiology

Microbiologia

Unit

Unidade

Antimicrobial Agents

Agentes Antimicrobianos

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

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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