Nutritional requirements of Arizona, Citrobacter, and Providencia

Association of bacteria with metacercarial cysts of Echinostoma caproni

Echinostoma caproni metacercarial cysts often need to be stored for several months to a year to meet laboratory requirements. This study examined the bacteria associated with encysted metacercariae stored at 4 degrees C. Bacterial assemblages from the kidney-pericardial region of uninfected snails and assemblages from the site of metacercarial infection in Biomphalaria glabrata were determined. Four species of Gram-negative rods were isolated and identified from the stored cysts to species or genus as Pseudomonas sp., Alcaligenes sp., Enterobacter cloacae, and Aeromonas hydrophila. Gram-positive rods were also isolated and included small slender rods (alpha hemolytic), small coccobacilli (gamma hemolytic), and small rods that exhibited gamma hemolysis. Accumulation of these bacteria on the surface of encysted metacercariae probably contributed to a decreased cyst viability of E. caproni.

Fatty acid composition of paracolons: Arizona, Citrobacter, and Providencia

The fatty acid compositions of stationary-phase cultures of Arizona arizonae, Citrobacter freundii, Providencia alcalifaciens, Providencia stuartii, and Providencia sp. were studied. The major fatty acids of A. arizonae, C. freundii, and Providencia were 16:0, 16:1, 17:cyclopropane, and 19:cyclopropane. The fatty acid compositions of the two strains of A. arizonae examined were similar to each other, but the three strains of C. freundii differed from one another in their fatty acid compositions. In both A. arizonae and C. freundii, the relative quantities of saturated, unsaturated, and cyclopropane fatty acids were similar to those which have been found in stationary-phase cultures of other members of the Enterobacteriaceae. The three strains of Providencia also differed from one another in their fatty acid compositions. In all three strains, the total quantity of unsaturated fatty acids was larger and that of the cyclopropane fatty acids was smaller than those found in stationary-phase cultures of other enteric bacteria.