Two N-halamine compounds, 3-chloro-4,4-dimethyl-2-oxazolidinone and 1,3-dichloro-4,4,5,5-tetramethyl-2imidazolidinone, were compared with free chlorine as to their effects on selected membrane functions of intact Staphylococcus aureus cells. Free chlorine was found to cause a loss of permeability control, as measured by the efflux of potassium from the cells and a dramatic increase in hydrogen ion permeability, and to affect cell respiration in a nonreversible fashion, as measured by oxygen uptake. The two N-halamines were found to have very little effect on permeability to either potassium or hydrogen ions but were both found to dramatically inhibit respiration in a reversible manner. It is proposed that the first step in the disinfection process by these N-halamines is an inhibition of respiratory enzymes that, if not reversed, ultimately leads to a loss of cell viability.

Discriminate analysis was used to evaluate the enzyme-linked immunosorbent assay (ELISA) for the detection of anti-Treponema hyodysenteriae antibodies in experimentally and naturally infected swine. In trial 1, 26 pigs were randomly divided into three groups (naturally infected, n = 8; experimentally infected, n = 11; and noninfected, n = 7), and samples were collected for 10 weeks. For trial 2, 31 pigs were randomly divided into two groups (naturally infected, n = 22; and noninfected, n = 7), and samples were collected for 20 weeks. Rectal swabs for T. hyodysenteriae isolation were collected daily, and fecal samples for isolation of Salmonella spp. were collected weekly. Serum samples for ELISA evaluation were collected biweekly (trial 1) or weekly (trial 2). Results of discriminate analysis indicated that the ELISA correctly identified 90% or more of the individually infected pigs at prior probabilities of infection ranging from 60 to 90%. The test correctly identified noninfected pigs at a lower rate (61 to 92% range). The mean ELISA titers of naturally infected pigs without clinical signs were not significantly different (P < 0.05) from the titers of both groups of experimentally infected pigs. Mean ELISA titers of naturally infected pigs without clinical signs were significantly greater than the mean titers of naturally infected pigs with clinical signs. Naturally infected pigs with clinical signs had a mean ELISA titer that was significantly greater than that of noninfected pigs and significantly less than the mean titers of the experimentally infected pigs without clinical signs and the naturally infected pigs without clinical signs.

The susceptibility of a strain of Legionella pneumophila to disinfection by an organic halamine, free chlorine, and a mixture of the organic halamine and free chlorine was assessed. The organic halamine was found to have superior stability in solution and to exhibit adequate disinfectant potential over a period of 1 month of repeated reinoculations of fresh bacteria. The combined halamine exhibited great potential for use in maintaining closed-cycle cooling water systems free of L. pneumophila.

Abstract. Monoclonal antibody in the identification ofCoagglutination tests were performed using a monoclonal antibody coagglutination assay. The monoclonal reagent was produced by incubating Cowan strain Staphylococcus aureus suspension, used as a source of crude protein A, with mouse ascitic fluid monoclonal antibody or goat anti-H. somnus hyperimmune serum. Bacteria to be tested were suspended at a concentration of 4.5 x 10 9 cells/ml. The coagglutination test was performed by the addition of 50 µ1 of the monoclonal reagent to 50 µ1 of the bacterial suspension on a glass plate and manual rotation for 2-3 minutes.The coagglutination assay using Cowan strain Staphylococcus aureus protein A, coupled with the monoclonal antibody, agglutinated 10 different H. somnus isolates. The antibody reagent did not coagglutinate with Actinobacillus suis, A. equuli, Pasteurella haemolytica, P. multocida, or P. pneumotropica under similar test conditions.

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Summary. Pelodera chitwoodi was able to distinguish between a Vibrio sp. (food bacterium) and Chromobacterium janthinum (non‐food bacterium), and between bacteria and mud. Nematodes migrated preferentially to the Vibrio sp. at various distances, temperatures, and pH values. Migration to food bacteria increased with an increase in bacterial concentration. Resting and dead bacteria failed to attract nematodes. Nematodes were able to detect a vibrio colony separated from them by a plastic barrier, and migrated to areas on agar containing exudate and dialysate from the vibrio. Both exudate and dialyzate contained 4 amino acids and 3 vitamins which attracted nematodes. However, attraction of nematodes to these compounds was not as strong as to metabolizing bacteria, indicating that additional compounds were also involved.