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Intestinal colonization of a human subject by vancomycin-resistant Enterococcus faecium
1Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jabotiçabal, Brazil.
Abstract:
OBJECTIVE: To study the ability of two strains of vancomycin-resistant Enterococcus faecium to colonize the human intestine. METHODS: A single human subject ingested separately two strains of vancomycin-resistant E. faecium isolated from a pig and a chicken. The feces were cultured on selective medium. Prior to ingestion no vancomycin-resistant cocci were present in the feces. Ingestion of 104-105 CFU resulted in either no colonization or isolation only after enrichment. Ingestion of 107 CFU of one strain resulted in colonization for a period of nearly 3 weeks, with fecal counts at times in excess of 106 CFU/g. Ingestion of similar numbers of the other strain and reingestion of the first strain resulted in excretion in the feces for much shorter periods. When the fecal count of the ingested strains was greater than 104-105 CFU/g, the strains were isolated from swabs taken from perianal skin. CONCLUSIONS: Vancomycin-resistant E. faecium strains from pigs and poultry are able to colonize the human gut and the perianal skin.
Insights
Vancomycin-resistant Enterococcus faecium (VRE) strains from food animals can colonize the human gut. High doses of VRE from pigs and poultry can lead to colonization for several weeks.
Area of Science:
- Microbiology
- Gastroenterology
- Public Health
Background:
- Vancomycin-resistant Enterococcus faecium (VRE) is a significant nosocomial pathogen.
- The potential for VRE transmission from food animals to humans is a growing concern.
Purpose of the Study:
- To investigate the colonization potential of VRE strains from food animals in the human intestine.
- To determine the duration and extent of VRE colonization and shedding.
Main Methods:
- A single human subject ingested two distinct VRE strains isolated from a pig and a chicken.
- Fecal samples were cultured on selective media to monitor VRE presence and quantify bacterial counts.
- Perianal skin swabs were also collected to assess extraintestinal colonization.
Main Results:
- Ingestion of 10^7 CFU of one VRE strain resulted in colonization for nearly 3 weeks, with fecal counts exceeding 10^6 CFU/g.
- The other strain and re-ingestion of the first strain showed shorter shedding periods.
- VRE was detected on perianal skin when fecal counts were high ( > 10^4-10^5 CFU/g).
Conclusions:
- VRE strains originating from pigs and poultry can successfully colonize the human gastrointestinal tract.
- Colonization and shedding dynamics vary between VRE strains.
- Perianal skin can serve as a reservoir for VRE following intestinal colonization.