Adherence of Acinetobacter baumannii to rat bladder tissue

Acinetobacter baumannii an important nosocomial pathogen, causes severe inf ections in patients of intensive care units, but its pathogenic attributes are unknown. Previously, the adherence of A. baumannii to cell lines has be en negative in the authors' laboratory. In this work, the adherence of stra ins of A. baumannii of various biotypes to small pieces of rat bladder tiss ue was investigated. Tissue pieces were submerged into cultures of A. bauma nnii and sessile cells were counted after removing planktonic bacteria. Fim briae and sessile cells were examined by transmission and scanning electron microscopy, respectively. in contrast to a uropathogenic strain of Escheri chia coli, all cultures exhibited a mannose- and galactose-resistant agglut ination of human group O red blood cells as well as mannose- and galactose- resistant adherence to the bladder tissue. Inhibition of exopolysaccharide synthesis did not modify adherence. Indeed, adherence, apparently unrelated to these fimbriae or to the exopolysaccharide, may be a factor contributin g to the pathogenicity of A. baumannii in the urinary tract or in other tis sues.