No abstract

Delays in initiation of treatment were more common than delays in the initial suspicion of tuberculosis. Both types of delays were common even in patients with disease that was confirmed by a positive smear. These data illustrate a need for improved education of physicians about the benefits of early initiation of therapy for tuberculosis.

Eikenella corrodens is a Gram-negative microaerophilic rod which is gaining recognition as an important human pathogen. We have previously reported the cloning and expression in Escherichia coli of a 3-6 kb Eik. corrodens genomic DNA fragment which encodes a 31.5 kDa haemagglutinin. Maxicell analysis revealed that this fragment also encodes two proteins of approximately 14 kDa. Nucleotide sequencing of the 2-2 kb fragment upstream of the haemagglutinin gene revealed two open reading frames with strong homology to genes encoding pilin subunit proteins of the type 4 or N-methylphenylalanine class. The two pilin genes, ecpA and ecpB, are complete and are expressed in E. coli. Southern analysis of ten additional Eik. corrodens strains revealed that all possess fragments homologous to ecpA. These data represent the first molecular evidence for pili in E. corrodens.

Non-typable Haemophilus influenzae is a common commensal organism in the human upper respiratory tract and an important cause of localized respiratory tract disease. The pathogenesis of disease begins with bacterial colonization of the nasopharynx, a process that involves establishment on the mucosal surface and evasion of local immune mechanisms. Under the proper circumstances, the organism spreads contiguously to the middle ear, the sinuses, or the lungs, and then stimulates a brisk inflammatory response, producing symptomatic infection. In this review, we summarize our present understanding of the molecular determinants of this sequence of events. Continued investigation of the molecular mechanism of non-typable H. influenzae pathogenicity should facilitate development of novel approaches to the treatment and prevention of H. influenzae disease.

Eikenella corrodens is emerging as an important human pathogen, in both extra-oral and periodontal infections. From a clone bank of Eikenella corrodens chromosomal DNA produced in Escherichia coli JM109, twenty-two clones expressed Eikenella antigens and of these, two expressed functional haemagglutinins. By virtue of different restriction maps and a lack of homology by Southern hybridization, the two cloned fragments encoding the two haemagglutinins have been shown to be distinct. Maxicell analysis revealed that clone 1, carrying plasmid pVKR201, produces three Eikenella proteins, one of 31.5 kDa and two of approximately 14 kDa each. Expression of each of the proteins appears to be under the control of an Eikenella promoter(s). Clone 2, carrying plasmid pVKR301, produces two proteins, one of 93 kDa and the second of 17 kDa. Expression of both of these proteins in E. coli requires the lac promoter in the vector. By preparing a series of subclones and testing each by maxicell analysis and for haemagglutination activity, a functional map of the insert of clone 1 was deduced and the 31.5 kDa polypeptide identified as the haemagglutinin. Using similar methods, the 17 kDa protein was found to be the haemagglutinin of clone 2. The nucleotide sequences of both haemagglutinin genes were determined and are presented. Computer analysis revealed no homology between the two haemagglutinins, and no homology to any previously sequenced proteins. These are the first genes of this genus to be cloned and sequenced.