Effect of subinihibitory and inhibitory concentrations of Plectranthus amboinicus (Lour.) Spreng essential oil on Klebsiella pneumoniae.

We evaluated the antimicrobial activity and some mechanisms used by subinhibitory and inhibitory concentrations of the essential oil, obtained from leaves of Plectranthus amboinicus, against a standard strain of Klebsiella pneumoniae and 5 multiresistant clinical isolates of the bacteria. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), the rate of kill and the pH sensitivity of the essential oil were determined by microdilution tests performed in 96-well plates. Subinhibitory and inhibitory concentrations of the essential oil were tested in order to check its action on K. pneumoniae membrane permeability, capsule expression, urease activity and cell morphology. The MIC and MBC of the essential oil were 0.09±0.01%. A complete inhibition of the bacterial growth was observed after 2 h of incubation with twice the MIC of the essential oil. A better MIC was found when neutral or alkaline pH broth was used. Alteration in membrane permeability was found by the increase of crystal violet uptake when the bacteria were incubated with twice the MIC levels of the essential oil. The urease activity could be prevented when all the subinhibitory concentrations were tested in comparison to the untreated group (p<0.001). Alteration of the bacterial morphology besides inhibition of the capsule expression was verified by atomic force microscopy, and Anthony's stain method, respectively. Our data allow us to conclude that the essential oil of P. amboinicus can be a good candidate for future research.

Tratamento etiológico da doença de Chagas no Brasil / Etiologic treatment of Chagas disease in Brazil

Nosso grupo de pesquisa tem desenvolvido experiências de monitoramento de reações adversas em pacientes chagásicos em tratamento com benznidazol. A proposta de produção deste artigo nasceu da constatação da escassez de artigos que reunissem vários aspectos relacionados ao tratamento etiológico da doença de Chagas. Portanto, foram realizadas buscas de artigos originais e revisões indexadas, nas bases do Medline e Lilacs, de publicações relativas ao tratamento etiológico da doença de Chagas desde os primeiros ensaios terapêuticos até o momento incluindo mecanismo de ação, reações adversas, critérios de cura e indicações de tratamento do consenso brasileiro. Os medicamentos nifurtimox e benznidazol, utilizados atualmente no tratamento da doença de Chagas, apresentam eficácia acima de 80por cento na fase aguda e de 8por cento a 30por cento na fase crônica. O sucesso da terapêutica esbarra em alguns pontos tais como: esquema terapêutico prolongado, reações adversas, variabilidade genética dos parasitos e cepas naturalmente resistentes aos fármacos. Os resultados desta atualização revelam a necessidade do desenvolvimento de novos fármacos com atividade anti-T. cruzi que, por um lado, apresentem menor toxicidade, e por outro, maior eficácia na fase crônica.

Salivary anti-PGL IgM and IgA titers and serum antibody IgG titers and avidities in leprosy patients and their correlation with time of infection and antigen exposure.

The present work proposed to correlate serum antibody avidity and salivary antibody titers as parameters for time of infection and antigen exposure in a cohort study evaluating leprosy patients in different periods of treatment. Colorimetric enzyme-immunoassays for salivary antibodies, serum antibody IgG titers and avidities were performed in the samples. Anti-PGL-1 IgA and IgM salivary antibodies were significantly higher in multibacillar (MB-L) patients compared to normal controls (p<0.05), but not when compared to borderline tuberculoid (BT) or to paucibacillar (PB-L) patients (p>0.05). A good correlation was found between salivary anti-PGL-1 IgA and IgM levels in MB-L patients (r=0.41, p<0.01). Two out of 33 tested saliva samples from patients who had completed the drug regimen treatment presented positive salivary antibodies. Among non-treated patients, samples with low, medium or high serum IgG antibody avidity were found in similar frequencies. In patients under treatment, most of the serum samples showed low or medium IgG antibody avidity. The treated MB-L patients showed medium or high antibody avidity, except for two, who showed very low antibody avidity results. We suggest that salivary anti-PGL antibodies and serum IgG avidity could be useful for the indication of recent exposure or re-exposure to bacteria after chemotherapy.

Salivary anti-PGL IgM and IgA titers and serum antibody IgG titers and avidities in leprosy patients and their correlation with time of infection and antigen exposure

The present work proposed to correlate serum antibody avidity and salivary antibody titers as parameters for time of infection and antigen exposure in a co-hort study evaluating leprosy patients in different periods of treatment. Colorimetric enzyme-immunoassays for salivary antibodies, serum antibody IgG titers and avidities were performed in the samples. Anti-PGL-1 IgA and IgM salivary antibodies were significantly higher in multibacillar (MB-L) patients compared to normal controls (p<0.05), but not when compared to borderline tuberculoid (BT) or to paucibacillar (PB-L) patients (p>0.05). A good correlation was found between salivary anti-PGL-1 IgA and IgM levels in MB-L patients (r=0.41, p<0.01). Two out of 33 tested saliva samples from patients who had completed the drug regimen treatment presented positive salivary antibodies. Among non-treated patients, samples with low, medium or high serum IgG antibody avidity were found in similar frequencies. In patients under treatment, most of the serum samples showed low or medium IgG antibody avidity. The treated MB-L patients showed medium or high antibody avidity, except for two, who showed very low antibody avidity results. We suggest that salivary anti-PGL antibodies and serum IgG avidity could be useful for the indication of recent exposure or re-exposure to bacteria after chemotherapy.

Response to polysaccharide antigens in patients with ataxia-telangiectasia

OBJECTIVE: To analyze the production of antibodies to polysaccharide antigens in patients with ataxia-telangiectasia.PATIENTS AND METHODS: We used the ELISA technique to measure the levels of IgG antibodies to serotypes 1, 3, 5, 6B, 9V and 14 of Streptococcus pneumoniae in 14 patients with ataxia-telangiectasia before and after immunization with 23-valent polysaccharide vaccine. Adequate response to individual polysaccharide can be defined as a postimmunization antibody titer equal to or greater than 1.3 µg/ml or as a minimum fourfold increase over the baseline (preimmunization) value. RESULTS: Six (43%) patients showed an absent response to all serotypes analyzed. Four patients showed adequate response to only one serotype, one patient to two serotypes, two patients to three serotypes and only one patient to four out of six serotypes analyzed. No patient had adequate response to all serotypes tested. Postimmunization pneumococcus IgG levels were higher than preimmunization levels to all serotypes analyzed, except for serotype 3. In spite of this, the mean postimmunization levels were lower than 1.3 µg/ml in all serotypes, except for serotype 14. Mean increment was less than four in all serotypes analyzed. CONCLUSION: Our results suggest that patients with ataxia-telangiectasia are at a high risk of having an impaired response to pneumococcus, which may be one of the causes of recurrent sinopulmonary infections in these patients.

Reações alérgicas a medicamentos / Allergic drug reactions

OBJETIVO: Rever as publicações recentes mais relevantes sobre alergia medicamentosa e oferecer ao clínico subsídios para uma maior compreensão dessa problemática de grande relevância para a saúde pública. FONTES DOS DADOS: Busca de artigos originais e revisões indexados nas bases MEDLINE, Pubmed e Lilacs, publicados na última década, relacionando o tema de alergia a medicamentos com mecanismos imunológicos, epidemiologia, diagnóstico laboratorial, lesões cutâneas, manejo clínico e reexposição ao fármaco. SíNTESE DOS DADOS: As reações alérgicas representam um terço das reações adversas a medicamentos. São consideradas eventos raros, mas com elevada morbimortalidade. Apesar da descrição de Gell & Coombs, útil para classificar reações alérgicas a fármacos, algumas permanecem sem classificação devido ao desconhecimento dos mecanismos imunológicos envolvidos. A existência de subpopulações de células T com características diversas daquelas comumente descritas revela a complexidade do tema e, ao mesmo tempo, elucida inúmeras questões inerentes ao mesmo. Recentemente, um novo conceito de apresentação de fármaco a linfócitos T surgiu, diante de evidências crescentes do seu envolvimento nas lesões cutâneas decorrentes de reações alérgicas a medicamentos. Na prática clínica, é muito difícil a correlação de sinais e sintomas das reações alérgicas a medicamentos com o mecanismo imunológico envolvido sem o auxílio de testes laboratoriais. Testes cutâneos in vivo e testes in vitro têm sido empregados nas suspeitas de reações alérgicas a medicamentos. No entanto, há poucos produtos comerciais adequados para sua execução. CONCLUSÕES: As reações alérgicas a fármacos constituem uma fração importante dos eventos adversos a medicamentos. É importante enfatizar a necessidade de notificação dessas reações pelos profissionais envolvidos no tratamento do paciente de forma sistematizada, por meio de ações de farmacovigilância, bem como a identificação dos possíveis mecanismos imunológicos envolvidos através de testes laboratoriais, história e avaliação clínica detalhadas.