Patients in the intensive care unit are exposed to amoeba-associated pathogens.
OBJECTIVE
To study the role of amoeba-associated alpha Proteobacteria as infecting agents in intensive care units (ICUs).


METHODS
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.


METHODS
The four university hospitals in Marseilles, France.


METHODS
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).


CONCLUSIONS
These preliminary results support the hypothesis that ICU patients are exposed to amoeba-associated alpha Proteobacteria.
Unité des Rickettsies, Hôpital de Ste Marguerite, Marseille, France.
Bernard
B
La Scola
Liazyd
L
Mezi
Jean-Pierre
JP
Auffray
Yvon
Y
Berland
Didier
D
Raoult
D020561:Alphaproteobacteria / Q000302:isolation & purification; D000656:Amoeba / Q000302:isolation & purification / Q000382:microbiology*; D000818:Animals; D018920:Coculture Techniques; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004197:Disease Reservoirs; D005602:France / Q000453:epidemiology; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D007362:Intensive Care Units; D011014:Pneumonia / Q000453:epidemiology / Q000382:microbiology*; D016036:Seroepidemiologic Studies; D014871:Water Microbiology