Patients in the intensive care unit are exposed to amoeba-associated pathogens

Infect Control Hosp Epidemiol. 2002 Aug;23(8):462-5. doi: 10.1086/502086.


Objective: To study the role of amoeba-associated alpha Proteobacteria as infecting agents in intensive care units (ICUs).

Design: Amoeba-associated alpha Proteobacteria were isolated from water samples taken from ICU taps and general hospital reservoir tanks using an amoebal co-culture procedure. Isolates were identified by 16S rDNA gene sequence comparison, and one isolate of each species was used as an antigen in a microimmunofluorescence assay to test the sera of the patients in the ICUs and compare them with those of control subjects.

Setting: The four university hospitals in Marseilles, France.

Patients: The sera of 85 patients in the ICUs with nosocomial pneumonia were tested.

Results: We isolated 64 bacterial strains that were identified as Afipia species or close relatives within the Rhizobiaceae subgroup of alpha Proteobacteria. These bacteria were assigned to 8 different species. Eleven patients were found to have an elevated antibody titer to either Afipia genospecies 1, or 3 still unnamed bacteria. No specific antibodies were detected in 100 control subjects (P < .01).

Conclusion: These preliminary results support the hypothesis that ICU patients are exposed to amoeba-associated alpha Proteobacteria.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alphaproteobacteria* / isolation & purification
  • Amoeba / isolation & purification
  • Amoeba / microbiology*
  • Animals
  • Coculture Techniques
  • Cross Infection / epidemiology
  • Cross Infection / microbiology*
  • Disease Reservoirs
  • France / epidemiology
  • Gram-Negative Bacterial Infections / epidemiology
  • Gram-Negative Bacterial Infections / microbiology*
  • Humans
  • Intensive Care Units
  • Pneumonia / epidemiology
  • Pneumonia / microbiology*
  • Seroepidemiologic Studies
  • Water Microbiology