Transmission phenotype of Mycobacterium tuberculosis strains is mechanistically linked to induction of distinct pulmonary pathology.

In a study of household contacts (HHC), households were categorized into High (HT) and Low (LT) transmission groups based on the proportion of HHC with a positive tuberculin skin test. The Mycobacterium tuberculosis (Mtb) strains from HT and LT index cases of the households were designated Mtb-HT and Mtb-LT, respectively. We found that C3HeB/FeJ mice infected with Mtb-LT strains exhibited significantly higher bacterial burden compared to Mtb-HT strains and also developed diffused inflammatory lung pathology. In stark contrast, a significant number of mice infected with Mtb-HT strains developed caseating granulomas, a lesion type with high potential to cavitate. None of the Mtb-HT infected animals developed diffused inflammatory lung pathology. A link was observed between increased in vitro replication of Mtb-LT strains and their ability to induce significantly high lipid droplet formation in macrophages. These results support that distinct early interactions of Mtb-HT and Mtb-LT strains with macrophages and subsequent differential trajectories in pathological disease may be the mechanism underlying their transmission potential.

Evaluation of processing methods to equitably aliquot sputa for mycobacterial testing.

We compared bacillary loads after splitting sputum specimens by chemical (N-acetyl-l-cysteine [NALC]) and mechanical homogenization by vortexing with sterile glass beads. NALC and vortexing with glass beads were equally effective at homogenizing sputum specimens, resulting in an equal distribution of tubercle bacilli in the aliquots.

Whole blood bactericidal activity during treatment of pulmonary tuberculosis.

The timely evaluation of new drugs that can be used to shorten tuberculosis (TB) treatment will require surrogate markers for relapse. This study examined bactericidal activity against intracellular Mycobacterium tuberculosis in whole blood culture (whole blood bactericidal activity; WBA) during TB treatment. In the absence of chemotherapy, immune mechanisms in patient blood resulted in bacteriostasis, whereas administration of oral chemotherapy resulted in bacillary killing. Total WBA per dose was greater during the intensive phase of treatment than during the continuation phase (mean, -2.32 vs. -1.67 log(10) cfu-days, respectively; P<.001). Cumulative WBA throughout treatment was greater in subjects whose sputum cultures converted to negative by the eighth week of treatment than in those for whom conversion was delayed (mean, -365 vs. -250 log(10) cfu-days; P=.04) and correlated with the rate of decrease of sputum colony-forming unit counts during the first 4 weeks of treatment (P=.018), both of which are indicative of prognosis. These findings indicate that measurement of WBA may have a role in assessing the sterilizing activity of new anti-TB drugs.

Infecçäo pela chlamydia trachomatis em adolescentes do sexo feminino / Chlamydia trachomatis infection in female adolescents

As adolescentes fazem parte de um grupo da populaçäo no qual é de grande importåncia o seguimentoda evoluçäodos comportamentos face às DST/Aids pois é uma fase de vida onde o risco de DST é mior. Objetiva validar um questionário a ser aplicado às adolescentes e estimar o tamanho de amostra necessário para um estudo de prevalência de chlamydia trachomatis e de alguns comportamentos de risco entre as adolescentes. Os dados foram coletados através de uma pesquisa quantitativa em um estudo descritivo com adolescentes - 15 a 19 anos. Foi aplicado um questionário face a face e coletado uma amostra de urina para testar CT usando LCX,nABBITT laboratories, após assinatura do termo de consentimento e autorizaçäodos pais. Os dados coletados estäo de acordo com os encontrados na literatura e seräo utilizados como paråmetro para estimar a frequência da infecçäo pela Chlamydia e determinar os fatores de risco associados