Assessment of serological assays for the diagnosis of HIV-1 infections.

Many serologic techniques are available for the detection of HIV-1 infection, but their diagnostic performances have been reported to vary depending on the testing situations. We evaluated eight different serologic assays for detecting HIV-1 antibody in sera from suspected high risk groups in North and East Africa. These included: one ELISA bead assay, three indirect ELISAs, two competitive ELISA assays, one gelatin agglutination assay and a recombinant dot-blot assay. A panel of 38 HIV-1 antibody confirmed positive human sera and a panel of 60 HIV negative sera were tested. All sera yielding discordant results were retested for verification of reactivity. Among the different assays evaluated for detecting HIV-1 antibody, sensitivities ranged from 0.919 to 0.974 and test efficiencies ranged from 94.2-98.9%. All assays failed to detect at least one western blot confirmed positive serum; three tests (Organon, DuPont recombinant and Serodia) produced only one false-negative result. Five of the eight assays did not produce any false-positive results. The Organon viral lysate and the DuPont recombinant ELISAs exhibited the best overall performance (test efficiency = 98.9%).

Potato-Like Odor of Retail Beef Cuts Associated with Species of Pseudomonas.

Retail cuts of beef and hamburger packages from a North Dakota meat processor were examined due to consumer complaints of a strong potato-like or musty odor associated with the meat. Examination for total numbers of aerobic bacteria on plate count agar and for gram-negative psychrotrophic bacteria on crystal violet tetrazolium agar revealed numbers in excess of 108 CFU/g. Numbers of coliform bacteria on violet red bile agar were in excess of 106 CFU/g. Gram-negative rods were isolated and identified. The isolates were characterized by a positive catalase reaction, oxidase production, an oxidative O/F reaction, nonutilization of lactose, liquefication of nutrient gelatin, slight motility, production of acid in litmus milk with decoloration and clotting, nonproduction of indole, and nonreduction of nitrate. The isolate was tentatively identified as a Pseudomonas of undetermined species, probably a variant of either Pseudomonas taetrolens or Pseudomonas perolens .

Re-examination of Rattus norvegicus as an animal model for Aeromonas-associated enteritis in man.

We have developed an oral feeding model for Aeromonas hydrophila enteritis using Rattus norvegicus with clindamycin pretreatment. All animals in the clindamycin group developed a self-limited, loose stool by day four of feeding. Intestinal examination revealed evidence of enteritis. Moreover, antibiotic usage may be a predisposing risk factor to infection.