Haroun N. Shah

Oral pathogens as contributors to systemic infections

Overview of a conference held at the Eastman Dental Institute and Hospital for Royal College of Surgeons of England, London, UK, 7–8 March 1996.

Noncultivable microbial communities in dentine and cementum: a molecular analytical approach.

poor cell yield on culture media, and production of mucoidal colonies that generally require a solid surface for attachment for successful growth. In this study, we directly analyzed the composition of nucleic acids in the dentine and cementum to determine the Table 1. Results of an examination of the correlation between the composition of the selected flora from dentinal tubules. clinical condition of teeth and the presence of colonizing bacteria. After removal of surface-associated soft tissues, the teeth were externally disinfected with 3% sodium hypochlorite. The teeth Amplifyable product from

Catalytic site targeted mutagenesis of the α-gingivain gene of Porphyromonas gingivalis using Tn-4351 to generate isogenic mutants

The extracellular proteinases of the anaerobe Porphyromonas gingivalis, are implicated in the destruction of host defence mechanisms in periodontitis. We have previously purified one of these enzymes, alpha-gingivain, and established that it belongs to the cysteine proteinase family of enzymes. In the present study, transposon Tn4351 was used to alter the open reading frame encoding a region that includes the catalytic site of alpha-gingivain by targeted mutagenesis. Escherichia coli HB101 which harbours R751 was used to introduce the transposon into P. gingivalis ATCC 33277 by conjugal transfer. E. coli was transformed using the altered plasmid with a Cla I site insertion of a sequence common to the catalytic site histidine or cysteine of many cysteine proteinases. The frequency of the transconjugation was 4.5 x 10(5) while the recipient viable counts comprised 60% of the original P. gingivalis. The result of this targeted mutagenesis was inactivation of gingivains such that some colonies on skimmed-milk agar plates showed no clear surrounding zones of hydrolysis and their normal catalytic activity towards L-BAPNA was destroyed.

Infección por Rhodococcus equi en pacientes con SIDA: Análisis retrospectivo de 13 pacientes en Argentina

INTRODUCTIONnRhodococcus equi is a gram positive coccoid rod that causes pulmonary infections in immunosuppressed patients.nnnMETHODSnWe retrospectively analyzed epidemiological, clinical, microbiological, radiological, and immunological features as well as the outcomes of 13 AIDS patients with R. equi infection.nnnRESULTSnBetween January 1994 and December 2012, 13 patients attending the AIDS department of the Infectious Diseases reference hospital in Buenos Aires were diagnosed with R. equi infection. All were men, the median age was 27 years. At the time of diagnosis, the median of CD4+ T cell counts was 11 cells/μl Twelve patients presented pulmonary disease with isolation of the microorganism from sputum or bronchoalveolar lavage; in the other patient the diagnosis was postmortem with positive culture of cerebrospinal fluid. The most frequent clinical manifestations were fever, haemoptysis, and weight loss. The predominant radiological finding was lobe consolidation with cavitation. Nine patients died after a median survival of 5.5 months. In all of them, cultures persisted positive until the last admission. The other 4 patients did continue clinical follow-ups.nnnCONCLUSIONnThe insidious course of R. equi disease and the difficulties in the isolation of the microorganism contribute to the delay in the diagnosis and to the high mortality rate of this opportunistic infection.