Infecções parasitárias do apêndice cecal e suas relações com apendicite aguda

Investigou-se a prevalência de infecções parasitárias do apêndice cecal e suas relações com a apendicite. Dos 1.600 apêndices estudados 24 (1,5%) apresentaram infecção parasitária. Enterobius vermicularis foi encontrado em 23 casos (95,8%) e Taenia sp em apenas um (4,2%). Dezesseis pacientes (66,7%) eram menores de 10 anos; 15 eram masculinos e 9 femininos. A análise histopatológica demonstrou inflamação aguda supurativa em 12 casos (50%), eosinofilia em 13 (54,2%) e hiperplasia linfóide em 10 (41,7%). Complicações como peritonite ocorreram em 11 e gangrena em 3 casos. As infecções parasitárias do apêndice são causa pouco freqüente de apendicite aguda em crianças e adolescentes.

Infecções cutâneas e acidentes por animais traumatizantes e venenosos ocorridos em aquários comerciais e domésticos no Brasil: descrição de 18 casos e revisão do tema

FUNDAMENTOS: O aquarismo a cada dia ganha novos adeptos no Brasil. Impulsionado por belos peixes e objetos de decoração, o hábito pode trazer problemas como infecções e envenenamentos por diversos animais. OBJETIVOS: Demonstração dos animais causadores e dos quadros clínicos envolvidos com estes acidentes, das infecções cutâneas encontradas após traumas e das medidas terapêuticas e preventivas para controle do problema, pouco conhecido pela população em geral. MÉTODOS: Utilizou-se um estudo prospectivo para a detecção de acidentes por animais e infecções ocorridas após traumas em aquários. Estes dados serviram de base para um estudo epidemiológico, clínico e terapêutico sobre o problema. RESULTADOS: em cerca de 300 acidentes por animais aquáticos, 12 ou 4% do total foram causados por animais venenosos em aquários. Cinco infecções bacterianas e uma fúngica foram identificadas após traumas em aquários. CONCLUSÕES: Os acidentes em aquários domésticos e comerciais são relativamente comuns e podem acarretar infecções cutâneas e ferimentos por animais venenosos ou traumatizantes. Os proprietários de aquários na maioria das vezes não têm informações sobre estes acidentes. Os autores fornecem as espécies de microorganismos e animais mais freqüentemente envolvidas com ferimentos e as medidas terapêuticas e preventivas adequadas ao manejo do problema.

Estudo sorológico de infecções experimentais por Trypanosoma evansi, em cobaias

Comparamos os métodos de Imunofluorescência Indireta (IFI), Imunodifusão Radial Dupla e Aglutinação, para a pesquisa de anticorpos em soros, na tripanossomíase experimental por Trypanosoma evansi, em cobaias. Foram obtidas 20 amostras de soro correspondentes às 4 primeiras semanas de infecção. A IFI foi positiva em apenas 6 animais, com títulos variando de 1:4 a 1:16. Os títulos mais altos foram observados na 3ª semana pós-infecção. Anticorpos aglutinantes foram observados a partir da 1ª semana pós-infecção e, após a 2ª semana, todos os animais apresentaram reação de aglutinação positiva, com títulos variando de 1:8.000 a 1:250.000. O tratamento dos soros com 2-Mercapto-etanol inibiu a reação de aglutinação, sugerindo ser IgM a principal classe dos anticorpos presentes no soro dos animais infectados. Não se constatou a presença de anticorpos precipitantes durante todo o curso da infecção.

Characteristics of Yersinia pseudotuberculosis isolated from animals in Brazil

Strains (105) of Yersinia pseudotuberculosis isolated in Brazil between 1982 and 1990 mere bio-serotyped. They were also studied for plasmid profile, autoagglutination and calcium dependence at 37 degrees C, Congo red uptake, pyrazinamidase activity, esculin hydrolysis, salicin fermentation and drug sensitivity: 95.24% were biotype 2, serogroup O:3; 2.86% were biotype 1, serogroup O:1; and 1.90% were biotype 2, non-agglutinable. Plasmids were found in 77.14% of the strains (one in each strain). There was total correlation between the presence of the virulence plasmid and autoagglutination, calcium dependence at 37 degrees C and Congo red uptake. The esculin, salicin and pyrazinamidase tests were not efficient in differentiating pathogenic from non-pathogenic Y, pseudotuberculosis isolates. All strains were highly sensitive to the drugs used. These results indicate that Y. pseudotuberculosis is a potential pathogen for humans in Brazil, especially because the bio-serogroups detected among animals are those most frequently associated with human diseases.

EVALUATION OF DIFFERENT TECHNIQUES FOR THE DIFFERENTIATION OF PATHOGENIC AND NON PATHOGENIC STRAINS OF YERSINIA-ENTEROCOLITICA

Different methods and tests have been used to evaluate the pathogenic potential of distinct Y. enterocolitica serotypes and biotypes. We tested a total of 60 Y. enterocolitica strains, being 25 of human origin (serotype O3 biotype 4 and serotype O5 biotype 1); 6 of animal origin (serotype O3 biotype 4); 19 isolated from the environment (serotype O5.27 biotypes 1 and 2); and 8 isolated from food (serotype O5 biotype 1 and serotype 05.27 biotype 1). The methods used were based on plasmid gene expression (autoagglutination, calcium-dependence at 37 degrees C and Congo Red absorption tests), chromosomal gene expression (assays for pyrazinamidase activity, salicin fermentation and esculin hydrolysis), and invasion of HEp-2 cells. All but one of the Y. enterocolitica O3 strains, were found to be potentially pathogenic when submitted to the pyrazinamidase-salicin-esculin tests. In contrast, the results obtained with the assays related to plasmidial gene expression were not so uniform, probably due to plasmid loss. The least homogeneous results were obtained with the HEp-2 cell invasion test. Y. enterocolitica O5 behaved in a uniform manner when tested with the first two groups of tests (based on chromosomal and plasmidial gene expression), but not when tested with the HEp-2 invasion assay. The strains of serotype O5.27 biotype 1 presented a uniform behavior hen submitted to the chromosomic-related tests, showing no pathogenicity. However, they did not provide conclusive results with the tests related to plasmidial gene expression or HEp-2 cell invasion. We conclude that the tests related to chromosomal gene expression (esculin-salicin-pyrazinamidase) are simple and highly effective for the detection of potentially pathogenic Y. enterocolitica isolated from clinical cases.

Kinetics of B cell response during Yersinia enterocolitica infection in resistant and susceptible strains of mice

In this study we analyze the B-cell response in murine yersiniosis. To this end, we determined whether polyclonal activation of B-lymphocytes occurs during infection of susceptible (BALB/c) and resistant (C57BL/6) mice with Y. enterocolitica 0:8 and compared the immunoglobulin (Ig) isotypes produced in response to the infection by the two strains. The number of splenic cells secreting nonspecific and specific immunoglobulins was determined by ELISPOT. The presence of anti-Yersinia antibodies in serum was detected by ELISA. In both strains, the number of specific Ig-secreting cells was relatively low. Polyclonal B-cell activation was observed in both strains of mice, and the greatest activation was observed in the BALB/c mice, mainly for lgG(1)- and IgG(3)- secreting cells. The C57BL/6 mice showed a predominance of IgG(2a)-secreting cells. The peak production of anti-Yersinia IgG antibodies in the sera of BALB/c mice was seen on the 28th day after infection. The greatest increase in IgM occurred on the 14th day. A progressive increase of specific IgG antibodies was observed in C57BL/6 mice up to the 28th day after infection while IgM increased on the 21st day after infection. The production of specific IgA antibodies was not detected in either BALB/c or C57BL/6 mice. We conclude that polyclonal. activation of B lymphocytes occurs in both the Yersinia resistant and Yersinia-susceptible mice and that the more intense activation of B lymphocytes observed in the susceptible BALB/c mice does not enhance their resistance to Y. enterocolitica infection.

AN IMPROVED ENRICHMENT PROCEDURE FOR THE ISOLATION OF YERSINIA-ENTEROCOLITICA AND RELATED SPECIES FROM MILK

A new enrichment procedure is proposed to improve the isolation of Yersinia enterocolitica and related species from milk. This procedure uses tryptic soy broth plus Polymyxin (5 IU/ml) and Novobiocin (10 mug/ml) - TSPN broth - incubated at 18-degrees-C for 3 d. Using raw milk and pasteurized milk inoculated with Yersinia strains, the efficiency of this procedure was compared to that of SB broth (sorbitol bile salts broth) incubated at 4-degrees-C for up to 21 d. Despite of the presence of antibiotics in TSPN broth, there were difficulties in recovering Yersinia organisms. Nevertheless, TSPN broth incubated at 18-degrees-C for 3 d showed better efficiency than that other method. In pasteurized milk samples, TSPN medium at 18-degrees-C for 3 d gave better results than the SB broth at 4-degrees-C for 7 d, showing that the proposed procedure is the preferable one due to the shorter period of incubation.