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Background. Several studies have demonstrated the presence of the Borrelia burgdorferi (Bb) genome in the myocardium of patients with dilated cardiomyopathy (DCM). To further support a causal relationship between the presence of Bb in the heart muscle and the development of DCM, demonstration of the absence of Bb in the myocardium of subjects with normal left ventricular (LV) systolic function is needed. Aim. To determine the prevalence of Bb by polymerase chain reaction (PCR) and electron microscopy (EM) in individuals with normal LV systolic function and no history suggestive of myocarditis. Methods. We investigated 50 patients (67 ± 9 years, 15 women) with normal LV ejection fraction (EF) = 50% undergoing cardiac surgery. During surgery, four samples from the right atrial appendage were obtained and subsequently examined by PCR and EM for the presence of Bb, and by immunohistochemistry to detect inflammatory cells. Serological testing of antibodies against Bb was also performed. Results. Neither PCR nor EM detected Bb in any of the subjects. Immunohistological examination revealed myocardial inflammation in 2 individuals (4%). Serological analysis by enzyme-linked immunosorbent assay demonstrated IgM antibodies against Bb in 4% and IgG antibodies in 12% of the study cohort; Western blot revealed IgM as well as IgG positivity in 14% of patients. Conclusions. The absence of Bb in the myocardium of individuals who undergo cardiac surgery and have normal LV systolic function supports the idea of Bb pathogenicity in the development of DCM. [ABSTRACT FROM AUTHOR]

A taxonomic study was conducted on 16 bacterial strains isolated from wild Adélie penguins (Pygoscelis adeliae) from Seymour (Marambio) Island and James Ross Island. An initial screening by repetitive sequence-based PCR fingerprinting divided the strains studied into four coherent groups. Phylogenetic analysis based on 16S rRNA gene sequences assigned all groups to the genus Corynebacterium and showed that Corynebacterium glyciniphilum and Corynebacterium terpenotabidum were the closest species with 16S rRNA gene sequence similarities between 95.4 % and 96.5 %. Further examination of the strains studied with ribotyping, MALDI-TOF mass spectrometry, comprehensive biotyping and calculation of average nucleotide identity and digital DNA–DNA hybridisation values confirmed the separation of the four groups from each other and from the other Corynebacterium species. Chemotaxonomically, the four strains P5828T, P5850T, P6136T, P7210T representing the studied groups were characterised by C 16:0 and C 18:1 ω9c as the major fatty acids, by the presence of meso -diaminopimelic acid in the peptidoglycan, the presence of corynemycolic acids and a quinone system with the predominant menaquinone MK-9(H 2). The results of this study show that the strains studied represent four new species of the genus Corynebacterium , for which the names Corynebacterium antarcticum sp. nov. (type strain P5850T = CCM 8835T = LMG 30620T), Corynebacterium marambiense sp. nov. (type strain P5828T = CCM 8864T = LMG 31626T), Corynebacterium meridianum sp. nov. (type strain P6136T = CCM 8863T = LMG 31628T) and Corynebacterium pygosceleis sp. nov. (type strain P7210T = CCM 8836T = LMG 30621T) are proposed. [ABSTRACT FROM AUTHOR]