Ocorrência de Vibrio spp potencialmente patogênicos em moluscos bivalves comestíveis comercializados nos anos 2000 a 2002 nos municípios da área de influência da Baía de Todos os Santos e Valença, Bahia - Brasil / Presence of potentially pathogenic Vibrio spp in edible bivalve shellfish commercialized during the years of 2000 to 2002 in the area of the Baía de Todos os Santos and Valença, Bahia - Brazil

Introduçäo. Víbrios estäo associados a diarréia em humanos após o consumo de água ou moluscos bivalves contaminados. Objetivos. Pesquisar a ocorrência de Vibrio ssp em moluscos bivalves comestíveis comercializados entre 2000 e 2002 nos municípios da área de influência da Baía de Todos os Santos e Valença. Materiais e Métodos. 122 amostras (107 de moluscos bivalves; 15 de zooplâncton) foram analisadas por métodos microbiológicos e moleculares (PCR; ERIC-PCR). Rsultados. 1077 cepas foram identificadas sendo 17 cepas Vibrio cholerae näo-O1 näo O139; 216 cepas Vibrio parahaemolyticus; 64 cepas Vibrio alginolyticus; 24 cepas Vibrio fluvialis e 14 cepas Vibrio vulnificus. As cepas de V. cholerae apresentam os cassetes de virulência incompletos, especialmente pela ausência dos genes ctxA E tcpA. Os dendrogramas de similaridade genética intraespecífica mostraram que há diversidade genética entre as espécies e cepas bacterianas isoladas. Conclusäo. Há risco de se contrair gastroenterite tanto pelo consumo de moluscos bivalves crus, mal cuzidos ou preparados em más condiçöes de higiene, adquiridos nos municípios da área de influência da Baía de Todos os Santos e Valença. As cepas implicadas em surtos de gastroenterites podem ser identificadas com futura contruçäo de banco de dados para uso em Vigilância Epidemiológica de gastroenterites, a partir dos perfis genotípicos obtidos via ERIC-PCR.

Clinical disease spectrum and pathogenic factors associated with Plesiomonas shigelloides infections in humans.

Plesiomonas shigelloides is a gram-negative, facultatively anaerobic rod whose appropriate taxonomic position is presently under investigation. The isolation and identification of this microorganism in contaminated specimens (e.g., feces) by a clinical laboratory depend on the screening of gram-negative colonies for oxidase and indole positivity and the appropriate use of selective and differential agars. Plesiomonads have been associated with extraintestinal diseases (bacteremia, meningitis) on rare occasions; they have been recovered sporadically from patients presenting with acute gastroenteritis. Although case reports and epidemiologic data support a role for P. shigelloides in diarrheal disease, laboratory investigations have failed to identify an enteropathogenic mechanism in these bacteria consistently or to reveal an animal model that faithfully reproduces the disease. Moreover, studies with volunteers have failed to establish an etiologic relation between Plesiomonas and bacterial gastroenteritis. An accurate picture of the role of this bacterium in human disease must await future studies.

Inclusion bodies in Plesiomonas shigelloides.

Inclusion bodies were discovered in seven environmental isolates of Plesiomonas shigelloides and the P. shigelloides control (ATCC 14029). Differential staining indicated that the inclusion bodies may be composed of polyphosphates, and developmental stages of the bodies may occur. The inclusion bodies may be useful for rapid presumptive identification of this organism.

[Ultrastructural organization of marine luminescent bacteria and their mutants]. / Osobennosti ul'trastrukturnoi organizatsii morskikh svetiashchikhsia bakterii i ikh mutantov.

The aim of this work was to study the submicroscopic organization of luminescent bacteria belonging to the genera Photobacterium and Lucibacterium as well as that of their "dark" mutants incapable of luminescence. The ultrastructural organization of all studied bacteria is typical of gram-negative species. The luminescent bacteria are characterized by the presence, in their cytoplasm, of osmophilic formations 22--110 nm in size. The cells of "dark" mutants accumulate volutin and contain complex membrane systems which are related to decelerated growth of the cultures.

Lipid-phase transitions of the strictly anaerobic bacteria Veillonella parvula and Anaerovibrio lipolytica.

As a basis for physicochemical studies on the membranes of the strictly anaerobic bacteria Veillonella parvula, Anaerovibrio lipolytica, and Megasphaera elsdenii, the fatty acyl and alk-1-enyl moieties on the phosphoglycerides of these organism were characterized. Uncommon is the high proportion of a heptadecenoic acyl and alk-1-enyl moiety in these three lactate-fermenting bacteria. In contrast to V. parvula and A. lipolytica, M. elsdenii contains high amounts of branched-chain acyl and alk-1-enyl moieties. Freeze-etching electron microscopy showed that the lipids of the plasma membranes of V. parvula and A. lipolytica go from the liquid crystalline to the gel state upon lowering of the temperature, indicating that the membrane lipids are predominantly in the fluid state. No lipid-protein segregation could be detected in the plasma membrane of M. elsdenii. This can be explained by the abundance of branched-chain fatty acyl and alk-1-enyl residues in the membranes of this organism which may prevent lipid-protein segregation during the lipid-phase transition.