Composition of Extracellular Polymeric Substances (EPS) produced by Flavobacterium columnare isolated from tropical fish in Brazil

Thirty nine isolates of Flavobacterium columnare from Brazilian fish farms had their carbohydrate composition of EPS evaluated by high efficiency liquid chromatography, using the phenol-sulfuric acid method of EPS. The occurrence of capsules on F. columnare cells was not directly related to biofilm formation, and the predominant monosaccharide is glucose.

Degradation of microcystins by adsorbed bacteria on a granular active carbon (GAC) filter during the water treatment process.

The degradation of microcystin by adsorbed bacteria on GAC (granular active carbon) filter from a water treatment facility was investigated. Dominant bacteria isolated from GAC were indigenous microorganisms, Psuedomonas sp. and Flavobacterium sp. The direct exposure of dominant GAC bacteria to microcystins resulted in a significant reduction of microcystin levels in both shaking and static conditions (t-test; p < 0.01). In bacteria-treatments, the half-life of microcystin was 2.6-3.5 days in both conditions. Based on this result, approximately 9-10 days would be estimated for 90% or up to 18-21 days of 99% of toxin to be degraded. This biological degradation by the GAC bacteria in combination with existing purification systems has potential to increase the efficiency of water purification.

Differentiation of nonfermentative gram-negative bacilli in the clinical laboratory.

A rapid and simplified system for the differentiation of nonfermentative Gram-negative bacilli, encountered frequently in clinical specimens, is presented for use in the clinical laboratory. Nonfermentative bacteria can be grouped initially by the motility, oxidase and OF glucose reactions. This grouping simplifies the choice of additional tests for further identification. The additional tests included Gram stain, acid production from 10% lactose agar, nitrate reduction, arginine dihydrolase activity, fluorescein production, deoxyribonuclease activity, hydrolysis of aesculin, growth at 42 degrees C, gelatinase activity and susceptibility to antibiotics.