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An indirect enzyme-linked immunosorbent assay (ELISA) using lipopolysaccharide extract as antigen was evaluated for detection of antibodies to Actinobacillus pleuropneumoniae serovar 15. The serovar 15 ELISA had a higher sensitivity and specificity than latex agglutination test for 63 and 80 sera from pigs experimentally infected and not infected with A. pleuropneumoniae, respectively. When the serovar 15 ELISA was applied to 454 field sera, high rates of seropositivity were found in pigs from farms infected with A. pleuropneumoniae serovar 15, but not in those from farms free of A. pleuropneumoniae serovar 15. The results suggest that the serovar 15 ELISA may be useful for the serological surveillance of infection with A. pleuropneumoniae serovar 15.

A glucose-negative group B strain of Neisseria meningitidis isolated from a meningitis case is described. A brief review of Neisseria identification procedures is also presented. Neisseria meningitidis is described as a nonmotile, nonsporeforming gram-negative diplococcus which is oxidase and catalase positive and produces acid but no gas from glucose and maltose and no acid from sucrose and fructose (3). The species also has four accepted (A, B, C, D) and five provisional (X, Y, Z, 29E, 135) serogroups based on antigenic specificities of their capsular polysaccharides. Most meningococcal disease is caused by groups A, B, C, and Y. More recently, subcapsular antigens have been utiized for division into serotypes independent of their serogroups (4). We report the isolation of a biochemically aberrant glucose-negative group B strain of N. meningitidis. The recovery of this strain led us to review Neisseria identification procedures. These fall into two categories: those based on carbohydrate degradation and those based on antigen-antibody reactions (3, 5). Carbohydrate degradation in "growth" and "nongrowth" test media (5) can be detected by indicator changes in tubes or wells and by a radiometric technique. The cystine-Trypticase (BBL Microbiology Systems) agar test (3) is an example of a growth carbohydrate degradation test in which the tubes are incubated for up to 72 h or longer before indicator color change can be observed. The Minitek (BBL Microbiology Systems) system (6) utilizes carbohydrate-impregnated paper disks which are inoculated with a suspension of the organism in a Neisseria broth. After 24 h, phenol red indicator changes are compared with color standards to determine breakdown of glucose, maltose, or fructose and