Febre purpúrica brasileira: caracterização rápida das cepas invasoras de Haemophilus aegyptius

Cepas de H. aegyptius isoladas em surtos de Febre Purpúrica Brasileira (FPB) no Brasil, foram caracterizadas pelo método de aglutinação em lâmina utilizando um anti-soro produzido com cepa de H. aegyptius isolada de cultura de sangue de paciente com FPB. Através desse método foi possível identificar cepas de H. aegyptius responsáveis por surtos de conjuntivite com características antigênicas iguais às cepas isoladas de FPB. A sensibilidade e especificidade da soroaglutinação em lâmina foi de 97,7% e 89,6% respectivamente, podendo ser utilizado como método de triagem em estudos de conjuntivites purulentas, para detectar cepas invasivas de H. aegyptius associadas a FPB, possibilitando assim a implantação de medidas que ampliem a eficiência na prevenção e na vigilância epidemiológica da doença.Strains of H. aegyptius isolated during outbreak of Brazilian Purpuric Fever (BPF) in Brazil were characterized antigenically by slide agglutination test utilizing antiserum produced with a H. aegyptius strain isolated from blood culture from a patient with BPF. By means of this method, it were identified H. aegyptius strains responsible for outbreaks of conjunctivitis with identical antigenic characteristics to strains isolated from BPF. The sensitivity and specificity of slide seroagglutination test was 97.7% and 89.6% respectively; therefore this assay was efficient to be used as a screening method in the studies of purulent conjunctivitis for detecting high risk populations for BPF, and to implement measures that will increase the efficiency of epidemiologic surveillance

Febre purpúrica brasileira, virulência em modelo animal do Haemophilus Aegyptius (H. influenzae biogrupo aegyptius)

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(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.Febre Purpúrica Brasileira (FPB) é causada por cepas invasoras de Haemophilus aegyptius (H. influenzae biogrupo aegyptius, Hae). Estas cepas invasoras foram diferenciadas de cepas de Hae associadas apenas a conjuntivites (cepas não invasoras) através de marcadores moleculares específicos. Modelo de ratos recém nascidos depletados de complemento foi aplicado ao estudo de cepas de Hae, associadas e não associadas a FPB, com o objetivo de se caracterizar seus potenciais de virulência. Com dose infectante de 10(5) células, as cepas invasoras causaram bacteriemia em 80-100% dos ratos inoculados,.e a magnitude da bacteriemia variou de 10(2,5±0,49) a >; 10(4,69) ufc/ml de sangue. Usando a mesma dose infectante as cepas controles não causaram bacteriemia frequente (0 a 50%) e a magnitude variou de 0 a 10(3,69±0,53) ufc/ml de sangue. As doses infectantes capazes de causar bacteriemia em 50% dos ratos inoculados (DB50%) para as cepas invasoras de Hae variaram de ; 10(7,3) bactérias. Imunização passiva com antissoros produzidos com cepas invasoras demonstrou que os ratos foram protegidos das bacteriemias causadas pelas cepas homólogas, mas não da infecção causada pela cepa heteróloga. Comparando a bacteriemia causada pelas cepas de Hae com a bacteriemia causada pelo H. influenzae b, cepa Eagan (Hib), foi demonstrado o maior potencial de invasibilidade de Hib. Este modelo animal demonstrou ser útil para esclarecer o maior potencial de virulência das cepas invasoras de Hae

Immunogenicity of a 23-valent pneumococcal polysaccharide vaccine in Brazilian elderly

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% females and 24.5% males) with a mean age of 71 years, and 19 young healthy adults (63.2% females and 36.8% 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

Isolamento de Haemophiliis aegyptius associado à Febre Purpúrica Brasileira, de cloropídeos (Diptera) dos gêneros Hippelates e Liohippelates Isolation of Haemophilus aegyptius associated to Brazilian purpuric fever from Hippelates and Liohippelates flies (Diptera: Chloropidae)

O reconhecimento da Febre Purpúrica Brasileira (FPB), em 1984, originou uma série de estudos que revelaram uma correlação desta doença com conjuntivites causadas por Haemophiliis aegyptius. A associação do aumento de conjuntivites em crianças e a maior densidade populacional de cloropídeos do gênero Hippelates já havia sido verificada desde o século passado. Este fenômeno está relacionado ao tropismo que estes insetos apresentam pelos olhos, secreções e feridas de onde se alimentam. Embora haja evidências do papel destes cloropídeos na transmissão mecânica de conjuntivites bacterianas, o isolamento de Haemophilus aegyptius a partir dos mesmos, no seu habitat natural, ainda não havia sido verificado. No presente trabalho obtivemos o isolamento de cepas invasivas de Haemophilus aegyptius, associadas à FPB, de duas coleções de cloropídeos, classificados como Liohippelates peruanus e uma espécie nova, Hippelates neoproboscideus, coletados ao redor dos olhos de crianças com conjuntivite.<br>The recognition of the Brazilian purpuric fever (BPF) in 1984 led to a number of studies which showed a relation between this disease and conjunctivitis caused by Haemophilus aegyptius. The increase in cases of conjunctivitis in children associated with higher population density of eye gnats (Chloropidae: Hippelates) has been reported since last century. This phenomenon is related to the attraction that those flies show for the eyes, secretions and wounds, from where they feed on. Although there are evidences on the role of these flies in the mechanical transmission of seasonal bacterial conjunctivitis, the isolation of Haemophilus aegyptius from them in their natural habitat had not been demonstrated yet. In this study Haemophilus aegyptius associated to BPF was isolated from two pools of chloropids collected around the eyes of children with conjuntivitis which were identified as Liohippelates peruanus (Becker) and a new species Hippelates neoproboscideus