ABSTRACT
Serum antibodies specific for the capsular polysaccharides of Streptococcus pneumoniae provide protection against invasive pneumococcal infection. In Brazil, this vaccine has been used for people over 65 years with clinical risk to develop pneumococcal infection since 1999. We evaluated the immune response of 102 elderly subjects (75.5 percent females and 24.5 percent males) with a mean age of 71 years, and 19 young healthy adults (63.2 percent females and 36.8 percent males) with a mean age of 27 years. The elderly study group consisted of outpatients who received follow-up care in the Geriatric Department of General Hospital, Faculty of Medicine, University of São Paulo. None had acute illness at the time of vaccination. Both groups were immunized with one intra-deltoid injection with 0.5 ml of a 23-valent pneumococcal polysaccharide vaccine. The total IgG specific antibody concentrations to capsular polysaccharides 1, 3, 5, 6B, 8, and 14 were determined against pre- and 1-month post-vaccination sera. All samples were analyzed according to the second-generation pneumococcal polysaccharide ELISA protocol. We observed that the pneumococcal polysaccharide vaccine evoked consistent antibody increase for serotypes 1, 5, 6B, 8, and 14 (geometric mean concentration increase of 2.46 in the elderly and 2.84 in the young adults). Otherwise, we observed no increase in antibody concentration for serotype 3 in both groups.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Pneumococcal Infections/prevention & control , Pneumococcal Vaccines/immunology , Streptococcus pneumoniae/immunology , Age Factors , Antibodies, Bacterial/immunology , Brazil , Case-Control Studies , Enzyme-Linked Immunosorbent Assay , Immunoglobulin G/immunologyABSTRACT
O reconhecimento da Febre Purpurica Brasileira (FPB), em 1984, originou uma serie de estudos que revelaram uma correlacao desta doenca com conjuntivites causadas por Haemophilus aegyptius. A associacao do aumento de conjuntivites em criancas e a maior densidade populacional de cloropideos do genero Hippelates ja havia sido verificada desde o seculo passado. Este fenomeno esta relacionado ao tropismo que estes insetos apresentam pelos olhos, secrecoes e feridas de onde se alimentam....
Subject(s)
Humans , Infant , Child, Preschool , Child , Adolescent , Haemophilus/isolation & purification , Haemophilus Infections/complications , Conjunctivitis, Bacterial/etiology , Conjunctivitis, Bacterial/microbiology , Haemophilus/classificationABSTRACT
Brazilian purpuric fever (BPF) is caused by invasive strains of Haemophilus aegyptius (H. influenzae biogroup aegyptius, Hae). These strains were differentiated from Hae strains associated only with conjunctivitis (non-invasive Hae strains) through specific molecular markers. Complement-depleted infant rat model was used to study the invasive and non-invasive Hae strains to compare their virulence potential. Inoculating 10(5) bacteria in the rats, the invasive strains caused 80 to 100 bacteremia and the intensity of bacteremia was 10(2.5 +/- 0.49) to > 10(4.69) cfu/ml of blood. Using the same infectious dose, the non-invasive strains did not cause frequent bacteremia (0 to 50) and the intensity was 0 to 10(3.69 +/- 0.53) cfu/ml of blood. The infectious doses able to cause 50 of bacteremia in the rats (BD 50) varied from < 10(3) to 10(4.2) bacteria for the invasive strains, whereas the BD 50 were 10(6.2) to > 10(7.3) bacteria for non-invasive strains. Passive immunization using antisera to invasive strains protected rats against bacteremia caused by homologous strains, but not by heterologous strain. By comparing the bacteremia caused by Hae and bacteremia caused by H. influenzae b (Eagan strain, Hib), it was demonstrated that Hib had higher virulence potential. This animal model was useful to clarify the virulence potential of invasive Hae strains.