5' exonuclease assay for detection of serogroup Y Neisseria meningitidis.

The incidence of serogroup Y meningococcal disease has increased recently in the United States. Here, we describe the development of a 5' exonuclease assay for the detection of serogroup Y Neisseria meningitidis and demonstrate the usefulness of this assay for resolving serogroup identification of strains that are resistant to conventional serogrouping and for the nonculture identification of serogroup Y meningococcal disease.

Phenotypic and genotypic properties of the genus Hafnia.

The present study characterised 73 Hafnia alvei isolates and five Escherichia isolates (originally identified as H. alvei) isolated from cases of diarrhoeal disease by the International Centre for Diarrhoeal Disease Research Branch (ICDDRB) in Bangladesh. Based upon the hydrolysis of arbutin and aesculin and the fermentation of salicin and D-arabinose, four distinct biotypes could be recognised among the 73 H.

Non-invasive Providencia alcalifaciens strains fail to attach to HEp-2 cells.

We investigated the adherence properties of six P. alcalifaciens strains with previously characterized differential invasive capabilities in HEp-2 cells. Highly invasive strains were found to attach to HEp-2 cell monolayers within 2 h post-infection and in large numbers on the eukaryotic cell surfaces within 3 h post-infection.

Biochemical identification and characterization of DNA groups within the Proteus vulgaris complex.

We placed 43 isolates belonging to the Proteus vulgaris complex into proposed DNA groups (genomovars) using five previously recommended tests (tests for esculin hydrolysis, production of acid from salicin, L-rhamnose fermentation, and elaboration of DNase and lipase). On the basis of the results of these five tests, 49% of the isolates fell into DNA groups 5 and 6, 37% fell into DNA group 2, and the remaining 14% fell into DNA groups 3 and 4. Sequencing of the 16S rRNA genes of 11 members of DNA groups 5 and 6 indicated that 10 of these isolates (91%) could be unambiguously assigned to one of these two genomospecies.

Identification and initial characterization of elastase activity associated with Vibrio cholerae.

Strains of Vibrio cholerae O1 (Ogawa, Inaba) and non-O1 serogroups have been found to produce an elastolytic protease that can be detected on 0.3% elastin agar plates or in broth cultures. The elastase enzyme appears to be maximally expressed in late log phase (14-18 h postinoculation) and has optimum activity at a pH range between 7 and 8.