Association between polyclonal B cell activation and the presence of autoantibodies in mice infected with Yersinia enterocolitica O:3

Eight-week old conventional female Swiss mice were inoculated intravenously with Yersinia enterocolitica O:3. A second group of normal mice was used as control. Five mice from each group were bled by heart puncture and their spleens were removed for spleen cell collection on the 3rd, 5th, 7th, 10th, 14th and 21st day after infection. Immunoglobulin-secreting spleen cells were detected by the isotype-specific protein A plaque assay. Total immunoglobulin levels were determined in mouse serum by single radial immunodiffusion and the presence of autoantibodies was determined by ELISA. We observed a marked increase in the total number of cells secreting immunoglobulins of all isotypes as early as on the 3rd day post-infection and the peak of secretion occurred on the 7th day. At the peak of the immunoglobulin response, the total number of secreting cells was 19 times higher than that of control mice and most immunoglobulin-secreting cells were of the IgG2a isotype. On the 10th day post-infection, total serum immunoglobul in values were 2 times higher in infected animals when compared to the control group, and continued at this level up to the 21st day post-infection. Serum absorption with viable Y. enterocolitica cells had little effect on antibody levels detected by single radial immunodiffusion. Analysis of serum autoantibody levels revealed that Y. enterocolitica infection induced an increase of anti-myosin and anti-myelin immunoglobulins. The sera did not react with collagen. The present study demonstrates that Y. enterocolitica O:3 infection induces polyclonal activation of murine B cells which is correlated with the activation of some autoreactive lymphocyte clones.

Prevalência, sazonalidade e intensidade de infecção por Diplostomum (Austrodiplostomum) compactum Lutz, 1928 (Digenea, Diplostomidae), em peixes do reservatório de Volta Grande, Estado de Minas Gerais, Brasil

The present study was conducted in the Aquaculture Station of Hydroeletric Power Station situated in Volta Grande Reservoir, MG, Brazil. Seventy freshwater corvinas, Plagiscion squamosissimus, and 66 tucunarés, Cichla ocellaris were captured bimonthly from April 2000 through April 2001 with net and hook. The helmints were identified as Diplostomun (A.) compactmn which showed the highest prevalence in the corvina's eyes in April 2000 (70%), February 2001 (80%) and April 2001 (60%), while in tucunaré occurred in April 2000 (33.3%), August 2000 (18.2%) and October 2000 (18.2%). Nevertheless, increase in the mean intensity of parasites was related in April (6.6), June (6.0), August (18.5) 2000 and February (5.7), April (4.8) 2001 for corvina and in August (16.0) and October (7.0) 2000 for tucunaré. Corvina's females showed infection during all period, while males did not show the same prevalence in June 2000 and April 2001. On the other hand, tucunare's males were infected in all months while females in August and October 2000. The highest prevalence in corvina was observed in the months which presented elevated water temperature (April, October, December 2000 and April 2001). The number of parasites collected in corvina on February 2000 was higher than the one observed in August 2000. The same was not observed for tucunaré. This work demonstrate corvina's high susceptibility to metacercariae of Diplostomum.

Metacercárias de Diplostomum (Austrodiplostomum) compactum Lutz, 1928 (Digenea, Diplostomidae) em peixes do rio Paraná, Brasil. Prevalência, sazonalidade e intensidade de infecção

This paper aims at evaluating the occurrence of Diplostommn (Anstrodiplostomum compactum (Digenea: Diplostomatidae) in the eyeball of Plagioscion sqnamosissimus (corvina) and Cichla ocellaris (tucunaré), monthly captured in Paraná river, Presidente Epitácio, state of São Paulo, Brazil. From 61 corvinas under analysis, 56 of them contained parasites (92%) with intensity rate of 42.0 host parasites. From an amount of 81 tucunarés, 45 contained parasites (55%) with intensity rate of 9.3 parasites. Corvinas showed prevalence from 71 to 100% with the highest intensity rates (103.3 and 106.9) from February to March, 2001. Comparatively, the tucunaré showed the highest prevalence from November 2000 (90%) to February 2001 (80%). The tucunaré highest intensity rates occurred on September, 2000 (12.7), December, 2000 (12.2) and February, 2001 (16.1). Metacercariae showed a hollow womb body and a posterior region of a sinuous conic protuberance, an oral sucker smaller than the acetabulae, a simple acetabulae located in the pre-equatorial region of helminto. A short pre-pharynx followed by a muscular pharynx, genital pore next to acetubulae. Corvina metacercariae presents 1.434,0 μm (880 to 1.840) long by 611.2 ± 93.4 μm (400 to 792) wide. Tucunaré metacercariae, 1.462.4 μm (960 to 2.480) by 710.8 μm (560 to 960). Authors confirmed corvina great susceptibility to Diplomastum and the relationship between the parasitism and the aquatic and climatic parameters.

Papel das proteínas Yops de Yersinia pseudotuberculosis na ativação dos linfócitos B

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Importância de Yersinia enterocolitica em microbiologia médica

Y. enterocolitica is a human invasive enteropathogen which causes a number of intestinal and extraintestinal clinical symptoms of various degrees of severity, ranging from mild gastroenteritis to mesenteric lymphadenitis, which mimics appendicitis and in rare cases can evolve to septicemia. Infection by Y. enterocolitica can also lead to post-infection immunological sequelae including arthritis, erythema nodosum and glomerulonephritis. Pathogenic Y. enterocolitica strains have traditionally been linked to specific biotypes and serogroups and associated to a variety of phenotypic characteristics related to virulence. Molecular genetics studies have pointed to the importance of the pYV virulence plasmid, which encodes various virulence genes, as well that of specific chromosomal virulence genes, in determining the pathogenesis of this bacterium. Intestinal infections by Y. enterocolitica are mostly self-limiting and usually do not need an antibiotic treatment. The occurrence of this microorganism is not as frequently described in Brazil as it is in other countries, such as Japan, USA and many European countries. This review focuses on the general characteristics, pathogenesis, clinical symptoms, virulence characteristics, treatment and antibiotic susceptibility of Yersinia enterocolitica strains isolated in Brazil and around the world.

Invasin of Yersinia pseudotuberculosis is not a polyclonal activator of mouse B lymphocytes

It is known that the invasin molecule of Yersinia pseudotuberculosis stimulates human peripheral B cells in vitro. In this work we evaluated the in vivo role of invasin as polyclonal activator of B lymphocytes in the mouse experimental model, by comparing strains of Y. pseudotuberculosis expressing invasin and isogenic inv mutants. Swiss mice were infected intravenously with two strains expressing invasin (YpIII pIB1 and an isogenic virulence plasmid-cured strain, YpIII) and with two invasin mutant strains (Yp100 pIB1 and Yp100, plasmid-cured). Spleen cells were sampled on days 7, 14, 21 and 28 after infection. Immunoglobulin (Ig)-secreting spleen cells were detected by protein A plaque assay and specific antibodies were detected in sera by ELISA. The virulent strain YPIII pIB1 (wild type) did not provoke polyclonal activation of B lymphocytes in vivo. In general, fewer Ig-secreting spleen cells of all isotypes were found in the infected animals than in the control animals. Specific IgG antibodies were detected in the sera of animals infected with all strains. The peak response occurred on the 21 st day post-infection, and the Yp100 strain provoked the highest level of these antibodies. We concluded that invasin is not a polyclonal activator of murine B cells.

Pattern of macrophage activation in yersinia-resistant and yersinia-susceptible strains of mice

Th1 cells, in cooperation with activated macrophages, are required to overcome Yersinia enterocolitica infection in mice. The pathway macrophages utilize to metabolize arginine can alter the outcome of inflammation in different ways. The objective of this study was to verify the pattern of macrophages activation in Y. enterocolitica infection of BALB/c (Yersinia-susceptible) and C57BL/6 (Yersinia-resistant) mice. Both strains of mice were infected with Y. enterocolitica O:8 WA 2707. Peritoneal macrophages and spleen cells were obtained on the 1st, 3rd and 5th day post-infection. The iNOS and the arginase activities were assayed in supernatants of macrophage cultures, by measuring their NO/citrulline and ornithine products, respectively. TGFβ-1 production was also assayed. The Th1 and Th2 responses were evaluated in supernatants of lymphocyte cultures, by IFN-γ and IL-4 production. Our results showed that in the early phase of Y. enterocolitica infection (1st and 3rd day), the macrophages from C57BL/6 mice produced higher levels of NO/citrulline and lower levels of ornithine than macrophages from BALB/c mice. The infection with Y. enterocolitica leads to an increase in the TGF-β1 and IL-4 production by BALB/c mice and to an increase in the IFN-γ levels produced by C57BL/6 mice. These results suggest that Y. enterocolitica infection leads to the modulation of M1 macrophages in C57Bl/6 mice, and M2 macrophages in BALB/c mice. The predominant macrophage population (M1 or M2) at the 1st and 3rd day of infection thus seems to be important in determining Y. enterocolitica susceptibility or resistance.

Ocorrência de infecção urinária em pacientes de um hospital universitário

Infection in hospitals is a serious problem for the Public Health System. It is responsible for the increasing number of hospital deaths, as well as the longer time patients may have to stay in hospital, raising the costs of confinement more and more. The most common hospital infection is urinary tract infections (UTI), the use of the urinary catheter being the main risk factor. The aim of this study was to evaluate the profile of UTI among hospitalized patients in a University Hospital in Brazil, from October to December 2003. Out of 271 samples of urine checked, 51 were positive, 27 of these from patients having community-acquired UTI and 24 whose infection originated in the hospital. The community-acquired UTIs were more frequent in female patients (63%). The highest incidence of infection was caused by Escherichia coli (74%), especially in patients aged from 0 to 15 (37%). The episodes of hospital-acquired infection happened, in the main, in male patients aged above 50 (68%) who were using a lasting vesical catheter; in this group of patients the infection was frequently caused by E. coli (29.1%) and Klebsiella spp. (29.1%). E. coli and Klebsiella pneumoniae exhibited strong resistance (62.5%) to trimethoprim-sulfamethoxazole, as well as to ampicillin, showing that these drugs should not be used to cure UTIs in this institution.

Contaminação microbiana das soluções de processamento radiográfico: Risco de infecção cruzada

Objective: To evaluate the microbial contamination in samples of radiographic developing and fixing solutions, radiographic processing water, dental unit waterlines and dental office's external water supply. Methods: Samples of 50 private dental offices and 20 dental offices of the School of Dentistry de Araçatuba-UNESP were collected. The samples were subjected to neutralization of the residual inhibitory agents followed by pre-enrichment in peptone water and EVA broth and were inoculated in selective and non-selective culture media. The DNA of the samples was extracted and the presence of superinfectant microorganisms was evaluated by PCR. The differences in the prevalence of the microorganisms in the samples of the solutions were analyzed by repeated-measures analysis of variance for category data, while the Chi-Square and Mann-Whitney tests were used to evaluate the existence of associations between the total number of heterotrophic microorganisms and infection control protocols. The significance level was set at 5%. Results: Samples of radiographic fixing solution presented a remarkably less frequent contamination than radiographic developing solution and radiographic processing water. The latter exhibited microorganisms typically originated from the oral microbiota and human skin as well as microorganisms frequently found in dental unit waterlines. There was less contamination of radiographic processing water in the dental offices where the x-ray film packets were disinfected before processing or were covered by a plastic film. Additionally, all samples of dental office's external water supply were drinkable. Conclusion: Covering the x-ray film packets with a plastic film protection barrier was proven the best manner to reduce the contamination of the evaluated solutions.

Sorofrequência de infecção pelo vírus da imunodeficiência felina e vírus da leucemia felina em gatos do município de araçatuba, são paulo

Feline immunodeficiency virus and feline leukemia represent important infectious diseases caused by retroviruses. This study aimed to investigate the prevalence of infection by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) in cats from the municipality of Araçatuba, São Paulo. Blood samples from 302 cats were collected and tested for the presence of antibodies against feline immunodeficiency virus and antigen of feline leukemia virus by ELISA ® Snap- Combo FIV-FeLV (IDEXX Laboratories). The frequency of FIV positivity was 5.63% (17/302) and of FeLV was 0.33% (1/302). Of the 17 cats infected with FIV, nine (52.94%) were symptomatic. There was a prevalence of FIV infection in males (p 0.0316) and cats aged between one and three years (p 0.0324).

Infecção pelo vírus da diarreia viral bovina em vacas gestantes abatidas no Estado de São Paulo-Brasil

The most important pathogens in the bovine livestock nowadays in the virus of the viral diarrhea mainly for triggered clinical manifestations related to the reproductive sphere. The infection in pregnant females, may result in abortions, embryonic resorptions, fetal mummification, birth of weak and malformation of the cattle. Moreover, their birth with persistently infected and immunotolerant virus, which the source of infection and dissemination of their disease. Nowadays, the complexity of the diagnosis and consequently its pathogenesis are tilted in the genotypic differences agent. So, this study aimed to verify the occurrence of the BVDV-1 (SINGER) and BVDV-2 (VS-253) genotypes in cows and their respective fetuses, slaughtered in an abattoir in the State of Sao Paulo. Through blood serum, using virus neutralization technique. All in all, 52,51% (115/219) of the cows which were tested reacted, but no fetus (0/219) reacted, to its virus neutralization. Through this cross-examination we observed that 42% (92/219) of cows reacted for both BVDV-1 and BVDV-2. Furthermore 4,10% (9/219) of them reacted only to the genotype BVDV-1 and 6,39% (14/219) responded only to the genotype 2 of BVDV. Therefore it was noticed that both strains are widespread in the regions studied, which justifies the use of different antigens to avoid false-negative diagnosis. Finally antibodies showed no fetus or fetal abnormalities, it is already developed and can be considered immunocompetent, independent child born to a reagent.