Name: chlamydiae life cycle and host infection
Uploaded: 2025-08-01T06:53:04.000Z
Duration: 1 min 29 s
Channel: JoVE

El filo Chlamydiae consta de un solo orden, Chlamydiales.Por lo general, estas especies son cocos pequeños, de aproximadamente 0,5 μm de diámetro, con un ciclo de desarrollo único y genomas reducidos con tamaños que oscilan entre 0,55 y 1 Mbp.Todas las especies de Chlamydiae son parásitos intracelulares obligados de varios huéspedes eucariotas, como las amebas de vida libre y los humanos.Los patógenos humanos mejor estudiados se encuentran en los géneros Chlamydia y Chlamydophila.La Chlamydia trachomatis causa tracoma, una de las principales causas de ceguera y diversas infecciones de transmisión sexual.Chlamydophila pneumoniae está relacionada con afecciones respiratorias, mientras que Chlamydophila psittaci es el agente causante de la enfermedad psitacosis.Las especies de Chlamydiae tienen un ciclo de vida único que involucra dos tipos de células.Los cuerpos elementales son células pequeñas, densas y no multiplicables, especializadas en la transmisión infecciosa.Después de la fagocitosis de los cuerpos elementales por las células huésped, se transforman en cuerpos reticulados y se multiplican dentro de las células huésped.A continuación, los cuerpos reticulados se transforman en cuerpos elementales. Se liberan tras la desintegración de la célula huésped, infectando las células cercanas y perpetuando el ciclo de vida.

filo bacteriano: chlamydia

Bacterial Phylum Chlamydiae

El filo Chlamydiae o Chlamydiota est&#225; compuesto por un &#250;nico orden, Chlamydiales. Este filo consiste exclusivamente en par&#225;sitos intracelulares obligados que infectan hu&#233;spedes eucariotas. Aunque los pat&#243;genos humanos de este grupo han sido ampliamente estudiados, el filo incluye muchas especies capaces de interactuar con diversos organismos eucariotas. Los miembros de Chlamydiae son t&#237;picamente cocos peque&#241;os, de aproximadamente 0,5 &#956;m de di&#225;metro, y presentan un ciclo de desarrollo caracter&#237;stico. Como ocurre con muchos par&#225;sitos y simbiontes intracelulares obligados, sus genomas est&#225;n reducidos, con tama&#241;os que oscilan entre 0,55 y 1 Mbp.
Las especies de este filo est&#225;n altamente especializadas para invadir y colonizar c&#233;lulas eucariotas, y diferentes especies se dirigen a una amplia gama de hu&#233;spedes. Por ejemplo, Parachlamydia acanthamoebae infecta amebas de vida libre, en particular aquellas del g&#233;nero Acanthamoeba. Durante la infecci&#243;n amebiana, Parachlamydia lleva a cabo el ciclo de desarrollo t&#237;pico observado en otras especies de clamidias. Muchas Chlamydiae pueden multiplicarse o persistir dentro de amebas de vida libre, lo que sugiere que estos hu&#233;spedes desempe&#241;an un papel significativo en la supervivencia y distribuci&#243;n de Chlamydiae en entornos naturales. Los an&#225;lisis de las secuencias del gen del ARNr 16S revelan una elevada diversidad de Chlamydiae en el medio ambiente, lo que indica su amplia presencia y la posible existencia de numerosos hu&#233;spedes naturales a&#250;n no descubiertos. Aunque P. acanthamoebae infecta naturalmente amebas, tambi&#233;n puede infectar a humanos, aunque de forma menos eficaz que las especies adaptadas al hu&#233;sped humano.
Los pat&#243;genos humanos m&#225;s estudiados pertenecen a los g&#233;neros Chlamydia y Chlamydophila. Entre ellos se encuentran especies como Chlamydophila psittaci, que causa la psitacosis; Chlamydia trachomatis, responsable del tracoma y otras enfermedades humanas; y Chlamydophila pneumoniae, asociada a ciertas afecciones respiratorias. La psitacosis es una epidemia aviar que ocasionalmente se transmite a humanos, provocando s&#237;ntomas similares a los de una neumon&#237;a. El tracoma, una enfermedad ocular debilitante caracterizada por vascularizaci&#243;n y cicatrizaci&#243;n corneal, es una de las principales causas de ceguera en el mundo. Otras cepas de C. trachomatis infectan el tracto genitourinario y se encuentran entre las infecciones de transmisi&#243;n sexual m&#225;s comunes.
Las clamidias se encuentran entre las bacterias bioqu&#237;micamente m&#225;s limitadas que se conocen, con genomas de aproximadamente 1 Mbp. Su capacidad biosint&#233;tica es a&#250;n m&#225;s restringida que la de las rickettsias, otro grupo de par&#225;sitos intracelulares obligados. Es especialmente notable que el genoma de C. trachomatis carece del gen que codifica la prote&#237;na FtsZ, considerada esencial para la formaci&#243;n del septo durante la divisi&#243;n celular en la mayor&#237;a de los procariotas. Adem&#225;s, se ha observado que ciertos genes de C. trachomatis parecen haber sido adquiridos de hu&#233;spedes eucariotas mediante transferencia horizontal de genes, lo que podr&#237;a mejorar su capacidad de supervivencia y proliferaci&#243;n en el interior de las c&#233;lulas hu&#233;sped.
El &#233;xito evolutivo de Chlamydiae radica en su estrategia de supervivencia eficiente, que implica la explotaci&#243;n de recursos del hu&#233;sped y la producci&#243;n de formas celulares resistentes para su transmisi&#243;n. El ciclo de vida de las clamidias implica dos tipos celulares distintos: (1) los cuerpos elementales, que son peque&#241;os, densos y especializados para la transmisi&#243;n infecciosa, y (2) los cuerpos reticulados, que son de mayor tama&#241;o, menos densos y constituyen la forma replicativa. Los cuerpos elementales son resistentes a la desecaci&#243;n y facilitan la transmisi&#243;n a&#233;rea, lo que los convierte en invasores particularmente eficaces del sistema respiratorio. En cambio, los cuerpos reticulados no son infecciosos y se multiplican dentro de las c&#233;lulas hu&#233;sped mediante fisi&#243;n binaria, generando un in&#243;culo considerable para infecciones posteriores.
Los cuerpos reticulados se transforman en cuerpos elementales tras m&#250;ltiples divisiones, liber&#225;ndose cuando la c&#233;lula hu&#233;sped se desintegra. Estos cuerpos elementales infectan entonces c&#233;lulas cercanas, perpetuando el ciclo. Se ha observado que los cuerpos reticulados se dividen con tiempos generacionales de 2&#8211;3 horas, una tasa significativamente m&#225;s r&#225;pida que la de las rickettsias. Sin embargo, a diferencia de las rickettsias, las clamidias no se transmiten mediante artr&#243;podos, sino que dependen principalmente de la dispersi&#243;n a&#233;rea.

Filo bacteriano: Chlamydia

El filo Chlamydiae o Chlamydiota est&#225; compuesto por un &#250;nico orden, Chlamydiales. Este filo consiste exclusivamente en par&#225;sitos ...

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chlamydiae life cycle and host infection

Chlamydiae are bacteria that live inside eukaryotic host cells. The phylum Chlamydiae, also called Chlamydiota, contains a single order, Chlamydiales. These bacteria are obligate intracellular parasites, which means they must enter host cells to survive and grow.

Members of this group are usually very small cocci, about 0.5 μm across. They also have reduced genomes, usually between 0.55 and 1 Mbp. This limited genome fits their highly specialized way of life and their dependence on host resources. Many species infect a wide range of eukaryotic organisms, not just humans.

Some Chlamydiae infect free-living amoebae, especially Acanthamoeba. Parachlamydia acanthamoebae is one example, and it follows the same developmental cycle seen in other chlamydial species during amoeba infection. Amoebae may help Chlamydiae survive and spread in natural environments, because many species can multiply or persist inside these hosts. 16S rRNA gene studies also show that Chlamydiae are very diverse in the environment, which suggests that many natural hosts are still undiscovered.

Human pathogens in this phylum are best known from the genera Chlamydia and Chlamydophila. Chlamydophila psittaci causes psittacosis, which is mainly an avian disease that can spread to humans and cause pneumonia-like symptoms. Chlamydia trachomatis causes trachoma and other human diseases, and some strains infect the genitourinary tract and are among the most common sexually transmitted infections. Chlamydophila pneumoniae is linked to certain respiratory conditions.

Chlamydiae are also known for their highly limited biochemistry. Their genomes are around 1 Mbp, and their biosynthetic abilities are even more restricted than those of rickettsias. The genome of C. trachomatis also lacks the gene for FtsZ, a protein that most prokaryotes use for septum formation during cell division. Some genes in C. trachomatis appear to have come from eukaryotic hosts through horizontal gene transfer, which may help the bacteria survive and multiply inside cells.

Their life cycle has two main forms. Elementary bodies are small, dense, and built for infection and transmission. They are resistant to drying, which helps airborne spread and makes them effective invaders of the respiratory system. Reticulate bodies are larger, less dense, and non-infectious. They multiply inside host cells by binary fission, with generation times of about 2 to 3 hours, which is faster than in rickettsias.

After several rounds of division, reticulate bodies change into elementary bodies. The host cell then breaks apart and releases them, allowing nearby cells to be infected and the cycle to continue. Unlike rickettsias, chlamydias are not spread by arthropods. They rely mainly on airborne dispersal.

Chlamydiae Life Cycle and Host Infection

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key terms and concepts

Learn how Chlamydiae infect host cells, switch between elementary and reticulate bodies, and cause diseases like trachoma, psittacosis, and STIs.

Chlamydiae Life Cycle and Host Infection | 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

Chlamydiae Life Cycle and Host Infection

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