Brucella cyclic ß-1,2-glucan plays a critical role in the induction of splenomegaly in mice.

Brucella, the etiological agent of animal and human brucellosis, is a bacterium with the capacity to modulate the inflammatory response. Cyclic ß-1,2-glucan (CßG) is a virulence factor key for the pathogenesis of Brucella as it is involved in the intracellular life cycle of the bacteria. Using comparative studies with different CßG mutants of Brucella, cgs (CßG synthase), cgt (CßG transporter) and cgm (CßG modifier), we have identified different roles for this polysaccharide in Brucella. While anionic CßG is required for bacterial growth in low osmolarity conditions, the sole requirement for a successful Brucella interaction with mammalian host is its transport to periplasmic space. Our results uncover a new role for CßG in promoting splenomegaly in mice. We showed that CßG-dependent spleen inflammation is the consequence of massive cell recruitment (monocytes, dendritics cells and neutrophils) due to the induction of pro-inflammatory cytokines such as IL-12 and TNF-α and also that the reduced splenomegaly response observed with the cgs mutant is not the consequence of changes in expression levels of the characterized Brucella PAMPs LPS, flagellin or OMP16/19. Complementation of cgs mutant with purified CßG increased significantly spleen inflammation response suggesting a direct role for this polysaccharide.

A multicenter retrospective study of childhood brucellosis in Chicago, Illinois from 1986 to 2008.

OBJECTIVES: To determine risk factors in children for the acquisition of Brucella, clinical presentation, treatment, and disease outcomes. METHODS: A retrospective multicenter chart review was undertaken of children identified with brucellosis from 1986 to 2008 at three tertiary care centers in Chicago, Illinois, USA. The charts were reviewed for data regarding risk factors for acquisition, clinical presentation, and outcomes. RESULTS: Twenty-one charts were available for review. The median age was 6.5 years (range 2-14 years); 62% were female. Ethnic background was 67% Hispanic and 24% Arabic. Risk factors included travel to an endemic area (86%), particularly Mexico, and consumption of unpasteurized milk products (76%). Common findings included fever (95%), bacteremia (86%), elevated liver transaminases (80%), constitutional symptoms (76%), splenomegaly (60%), and hepatomegaly (55%). Relapse occurred in three of six subjects started on single drug treatment, but in only one of 15 subjects who started on two or more drugs (p=0.053). No relapses occurred in children whose initial therapy included rifampin or those administered three-drug regimens. CONCLUSIONS: Brucella is an infrequent pathogen but should be considered in children with compatible epidemiologic and clinical characteristics. Blood cultures should be obtained, and initial therapy with two or more drugs may decrease the risk of relapse.

Bacteremia, fever, and splenomegaly caused by a newly recognized bartonella species.

Bartonella species cause serious human infections globally, including bacillary angiomatosis, Oroya fever, trench fever, and endocarditis. We describe a patient who had fever and splenomegaly after traveling to Peru and also had bacteremia from an organism that resembled Bartonella bacilliformis, the causative agent of Oroya fever, which is endemic to Peru. However, genetic analyses revealed that this fastidious bacterium represented a previously uncultured and unnamed bartonella species, closely related to B. clarridgeiae and more distantly related to B. bacilliformis. We characterized this isolate, including its ability to cause fever and sustained bacteremia in a rhesus macaque. The route of infection and burden of human disease associated with this newly described pathogen are currently unknown.

[Hepatosplenic candidiasis in acute myeloid leukemia]. / Candidiasis hepatoesplénica en un paciente con leucemia mieloide aguda.

Chronic diseminated candidiasis--mainly its hepatosplenic form- is one of the most characteristic invasive infection due to Candida in haematological patients. A case is presented of a 31 year old man admitted to the Clinical Department with acute mieloid leukosis M2, showing febrile neutropenia after induction and consolidation chemotherapy. Hepatoesplenic candidiasis was diagnosed and confirmed by computered axial tomography (CAT) and hepatic biopsy; amphotericin B followed by liposome encapsuled amphotericin B up to complete a total dose of 4 g was used for treatment. The patient was discharged waiting for bone marrow transplantation. Early suspicion of hepatosplenic candidiasis helps to select a rapid diagnosis method and an effective treatment.

Hepatosplenomegaly caused by an extract of cyanobacterium microcystis aeruginosa bloom collected in the Manguaba laggon, Alagoas - Brazil

Cyanobacteria (Microcystis aeruginosa), which produce powerful hepatotoxic cyclopetpides, were collected and submitted to the determination of toxicity through intraperitoneal injections made in 30 and 90 days-old Swiss albino mice. The liver and the spleen were histopathologically analyzed and the weight and vital signs development were monitored. Test of toxicity resulted in a LD 50 of 154.28 mg.Kg -1 . M.aeruginosa represented 95 (per cent) of the analyzed biomass. The ratios between liver weight and body weight in the animal inoculated with a single dose were 6.0 (per cent) and 7.2 (per cent), with multi doses 7.0 (per cent) and 7.5 (per cent) and in the control animals 4.0 (per cent) and 5.0 (per cent), for adult and young animals, respectively . There was an accentuated increase in the volume and weight of the spleen, and the animals inoculated with a single dose showed a ratio between spleen weight and body weight of 0.67 (per cent) and 0.37 (per cent), with multidoses 1.22 (per cent) and 1.05 (per cent) and the control animals the ratio was 0.12 (per cent) and 0.15 (per cent), for adult and young animals, respectively. The young animals inoculated with single and multi doses had an increase of 150 (per cent) and 407 (per cent) in the spleen size while the adults increased, 607 (per cent) and 845 (per cent), respectively, in relation to the control. The histopathological analysis showed strong differences in the structure of the hepatic parenchyme in control animals and in those exposed to the M.aeruginosa extract. The main alterations were the congestive aspect, including the sinusoid, and intrahepatic haemorrhagia. The histopathological analysis showed considerable increase in the number of multinuclear giant cells in the spleen of the animals intoxicated by M.aeruginosa.

Acute splenic sequestration together with aplastic crisis caused by human parvovirus B19 in patients with sickle cell disease.

Three children with homozygous sickle cell disease, 22 months and 8 and 10 years of age, had clinical and hematologic manifestations of aplastic and splenic sequestration crisis simultaneously. They had an acute drop in hemoglobin level (16, 20, and 45 gm/L), reticulocytopenia (0.1%, 0.6%, and 0.3%), and sudden splenic enlargement. Evidence of recent parvovirus infection was demonstrated.

Congenital toxoplasmosis in twins: a series of 14 pairs of twins: absence of infection in one twin in two pairs.

Fourteen pairs of twins with congenital toxoplasmosis were observed. In two pairs, one twin was infected and had symptoms of chorioretinitis or encephalomyelitis, while the other had a negative dye test upon repeated examination: this phenomenon has not previously been reported. In three of the other twelve pairs of twins, one of each pair died; two of them had evidence of toxoplasmosis; in the cotwin the diagnosis was based on serologic data. Clincial and biologic follow-up extended from 19 months to 8 years in five pairs. Marked discrepancies in the individual clinical patterns of the two children in each of six sets of twins were observed, with evidence of infection in one twin and subclinical infection in the other. These clinical findings correlated well with serologic data in the children in whom sufficient follow-up was permitted. The clinical pattern of congenital toxoplasmosis in twins is extremely similar in monochorial pregnancies, but discrepancies are almost the rule in bichorial pregnancies. The importance of placental lesions in determining the extent of fetal involvement is well illustrated by studies of toxoplasmosis in twins.