Legionella-Like and Other Amoebal Pathogens
Legionella-Like and Other Amoebal Pathogens
We tested serum specimens from three groups of patients with pneumonia by indirect immunofluorescence against Legionella-like amoebal pathogens (LLAPs) 1-7, 9, 10, 12, 13; Parachlamydia acanthamoeba strains BN 9 and Hall's coccus; and Afipia felis. We found that LLAPs play a role (albeit an infrequent one) in community-acquired pneumonia, usually as a co-pathogen but sometimes as the sole identified pathogen.
A number of bacteria that grow only within amoebae and are closely related phylogenetically to Legionella species, Legionella-like amoebal pathogens (LLAPs), have been identified and characterized. The role of these bacteria as human pathogens is still largely unknown. Other microorganisms, e.g., Parachlamydia acanthamoeba strains BN 9 and Hall's coccus, also grow within amoebae. Afipia felis (once thought to be the etiologic agent of cat-scratch disease), a gram-negative rod, is difficult to grow on artificial medium but grows well in human monocytes and HeLa cells; this organism was recently reported to be an environmental bacterium probably associated with free-living amoebae and living in water. We tested serum specimens from three groups of patients with pneumonia to determine if any of these microorganisms cause disease.
We tested serum specimens from three groups of patients with pneumonia by indirect immunofluorescence against Legionella-like amoebal pathogens (LLAPs) 1-7, 9, 10, 12, 13; Parachlamydia acanthamoeba strains BN 9 and Hall's coccus; and Afipia felis. We found that LLAPs play a role (albeit an infrequent one) in community-acquired pneumonia, usually as a co-pathogen but sometimes as the sole identified pathogen.
A number of bacteria that grow only within amoebae and are closely related phylogenetically to Legionella species, Legionella-like amoebal pathogens (LLAPs), have been identified and characterized. The role of these bacteria as human pathogens is still largely unknown. Other microorganisms, e.g., Parachlamydia acanthamoeba strains BN 9 and Hall's coccus, also grow within amoebae. Afipia felis (once thought to be the etiologic agent of cat-scratch disease), a gram-negative rod, is difficult to grow on artificial medium but grows well in human monocytes and HeLa cells; this organism was recently reported to be an environmental bacterium probably associated with free-living amoebae and living in water. We tested serum specimens from three groups of patients with pneumonia to determine if any of these microorganisms cause disease.
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