Publication: Papel de la colonización por clones de alto riesgo en la transmisión e infección por "Enterococcus faecium"
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2018-02-19
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Universidad Complutense de Madrid
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Abstract
En las últimas décadas Enterococcus faecium ha pasado de considerarse un simple microorganismo comensal del TGI humano para convertirse en una de las principales causas de infección nosocomial. La emergencia de E. faecium como patógeno hospitalario ha coincidido con la diseminación a nivel de una subpoblación genética altamente adaptada al hospital, perteneciente a tres linajes principales:ST17, ST18 y ST 78. Esta subpoblación se caracteriza por presentar resistencia a numerosos antibióticos de uso clínico como la ampicilina, el levofloxacino y en ocasiones también a la vancomicina, además de estar enriquecida en una serie de factores putativos de virulencia. Los pacientes oncohematológicos en tratamiento quimioterápico tienen un riesgo elevado de desarrollar infecciones que se ha demostrado proporcional a la intensidad y duración de la neutropenia. Con el objetivo de disminuir la incidencia de infección en estos pacientes, se ha generalizado la administración de profilaxis antibiótica, principalmente con fluoroquinolonas. En los últimos años se ha observado un cambio en la etiología de los procesos infecciosos en estos pacientes: mientras que en los años ochenta predominaban los bacilos gramnegativos, en la actualidad han aumentado el porcentaje de las mismas debidas a microorganismos grampositivos. Los principales factores que parecen explicar este cambio son la utilización de quimioterapias más agresivas, la utilización generalizada de catéteres permanentes y el empleo de profilaxis con fluoroquinolonas. La bacteriemia en pacientes neutropénicos se ha asociado a un tercio de los episodios febriles y con frecuencia tienen un origen endógeno en el tracto gastrointestinal del paciente. En los últimos años E. faecium se ha convertido en una de las principales causas de bacteriemia en el ámbito hospitalario, especialmente en pacientes con algún tipo de inmunosupersión. Su alta capacidad para colonizar y sobrecrecer en el tracto gastrointestinal de los pacientes y sobre distintas superficies, explica parcialmente su éxito en la diseminación y producción de infección a nivel nosocomial. Sin embargo, la dinámica de estos procesos, así como el conocimiento de las características inherentes a este microorganismo que los favorecen no se conocen en profundidad...
In the last decades Enterococcus faecium has evolved from being considered as a simple commensal of the human gastrointestinal tract to become one of the leading causes of nosocomial infection. The emergence of E. faecium as a nosocomial pathogen has coincided with the spread of a subpopulation highly adapted to hospital setting and belonging to three main lineages: ST17, ST18 and ST 78. This subpopulation is characterized by resistance to many antibiotics such as ampicillin, levofloxacin and eventually also vancomycin. In addition, clones belonging to these lineages are enriched in some virulence determinants such as EspEfm, Acm or HylEfm. Oncohaematologic patients under chemotherapy are at a higher risk of developing infections, being this risk proportional to the intensity and duration of neutropenia. In order to reduce the incidence of infection, the administration of antibiotic prophylaxis, mainly with fluoroquinolones, has been widely used amongst these patients. In recent years, an important change in the etiology of these patients’ infections has been noted worldwide: while gramnegative bacilli predominated in the 1980s, an increase in the number due to grampositive microorganisms has been reported. The main factors that seem to explain this etiological switch are the administration of more aggressive chemotherapies, the widespread use of indwelling catheters and the administration of fluoroquinolone prophylaxis. Neutropenic patients’ bacteraemia has been associated with one-third of the febrile episodes and it often has an endogenous origin in the gastrointestinal tract. In recent years E. faecium has emerged as a main cause of nosocomial bacteraemia especially in patients with some type of immunosuppression. The ability of this microorganism to colonize and overgrow in the patient’s intestine and onto different surfaces partially explains its success in the dissemination and infection development in the hospital setting. However, a comprehensive understanding of these processes dynamics and of the inherent characteristics of this microorganism that might favour the colonization/infection and transmission are needed...
In the last decades Enterococcus faecium has evolved from being considered as a simple commensal of the human gastrointestinal tract to become one of the leading causes of nosocomial infection. The emergence of E. faecium as a nosocomial pathogen has coincided with the spread of a subpopulation highly adapted to hospital setting and belonging to three main lineages: ST17, ST18 and ST 78. This subpopulation is characterized by resistance to many antibiotics such as ampicillin, levofloxacin and eventually also vancomycin. In addition, clones belonging to these lineages are enriched in some virulence determinants such as EspEfm, Acm or HylEfm. Oncohaematologic patients under chemotherapy are at a higher risk of developing infections, being this risk proportional to the intensity and duration of neutropenia. In order to reduce the incidence of infection, the administration of antibiotic prophylaxis, mainly with fluoroquinolones, has been widely used amongst these patients. In recent years, an important change in the etiology of these patients’ infections has been noted worldwide: while gramnegative bacilli predominated in the 1980s, an increase in the number due to grampositive microorganisms has been reported. The main factors that seem to explain this etiological switch are the administration of more aggressive chemotherapies, the widespread use of indwelling catheters and the administration of fluoroquinolone prophylaxis. Neutropenic patients’ bacteraemia has been associated with one-third of the febrile episodes and it often has an endogenous origin in the gastrointestinal tract. In recent years E. faecium has emerged as a main cause of nosocomial bacteraemia especially in patients with some type of immunosuppression. The ability of this microorganism to colonize and overgrow in the patient’s intestine and onto different surfaces partially explains its success in the dissemination and infection development in the hospital setting. However, a comprehensive understanding of these processes dynamics and of the inherent characteristics of this microorganism that might favour the colonization/infection and transmission are needed...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Microbiología II, leída el 15-06-2017