Fatal community-acquired Bacillus cereus pneumonia in an immunocompetent adult man: a case report.

BACKGROUND: Bacillus cereus is a gram-positive rod bacterium that is responsible for food poisoning. It is naturally widely distributed, and thus often contaminates cultures. Although it is rarely considered responsible, it can cause serious infections under certain conditions. However, lethal infections, especially in immunocompetent patients, are rare. CASE PRESENTATION: A healthy 60-year-old man developed community-acquired B. cereus pneumonia and alveolar hemorrhage unveiled by abrupt chest pain and hemoptysis with no other advance symptoms. B. cereus induced silent alveolar destruction without any local or systemic inflammatory response. Although the lesion resembled lung anthrax, there was no evidence of Bacillus anthracis toxin. CONCLUSIONS: Some isolates of B. cereus can cause anthrax-like fulminant necrotizing pneumonia in immunocompetent patients. If this type of B. cereus were used as a means of bioterrorism, it may be quite difficult to recognize as bioterrorism. We should keep B. cereus in mind as a potential pathogen of fulminant human infectious disease.

Contrasting genetic structure of closely related giant water bugs: phylogeography of Appasus japonicus and Appasus major (Insecta: Heteroptera, Belostomatidae).

Appasus japonicus and A. major, two belostomatid species of the giant water bug found in parts of East Asia, have very similar morphological characteristics and ecological niches, and also overlapping habitats. However, the results of our previous published study utilizing molecular phylogenetic analyses of mitochondrial and nuclear DNA revealed extensive genetic differences, which indicated that the possibility of inter-specific hybridization was extremely unlikely. We collected A. japonicus and A. major from the Japanese Archipelago, Korean Peninsula, and Russian Far East, and conducted molecular analyses of mitochondrial DNA COI and 16S rRNA to compare phylogenetic relationships between these species. Three major clades were recognized within A. japonicus. Specimens from the Korean population constituted a monophyletic clade, and were a sister group of the western region of the Japanese Archipelago. The Eastern Japanese clade was clearly differentiated. Four major clades were recognized within A. major. Specimens from the Japanese and Korean populations revealed two distinct monophyletic clades. Significant differentiation was clearly observed between their genetic structures. Furthermore, the results of mismatch distribution and Bayesian skyline plot analyses suggested the possibility of a bottleneck effect or founder effect in two of the A. major clades. Collectively, these results demonstrated both similarities and differences in these two species even though their distribution widely overlaps in East Asia, with their morphological characteristics and ecological niches being very similar. These differences in genetic structures are considered to be due to their evolutionary history.

Massive right pleural effusion and ascites caused by a primary constrictive pericardial band.

A previously healthy 57-year-old woman with peripheral edema and exertional dyspnea had diminished right breath sounds and edema of both legs. Chest radiography showed massive right pleural effusion, and abdominal computed tomography showed ascites. During cardiac catheterization, pressure curves of both ventricles showed "dip-and-plateau" patterns. We diagnosed constrictive pericarditis and conducted pericardiectomy. During surgery, we found a thick fibrous pericardium surrounding the entire heart and a band of calcium in the atrioventricular groove. Histological examination of excised pericardial tissue showed fibrosis, hyalinization, and calcification, with thickening of < or = 18 mm. Cases of localized pericardial thickening, including constricting bands in the atrioventricular groove, are rare and many such complications occur postoperatively. We report a rare case of primary constrictive pericardial band resulting in massive right pleural effusion and ascites.

Removal of a splenic artery with a large aneurysm adhered to the pancreas without pancreatectomy: report of a case.

Splenic artery aneurysms account for about 60% of all visceral aneurysms. The treatment include surgical procedures that sometimes require pancreatectomy. This report describes the case of a 64-year-old woman who had multiple splenic artery aneurysms with various visceral artery dilatations. Because there was no obvious cause for the splenic artery aneurysms and other arterial abnormalities, we suspected an anomaly of the connective tissue, which was subsequently confirmed by a postoperative histopathologic examination. Thus, we decided to remove the whole splenic artery, to eliminate the formation of any further aneurysms, as well as a splenectomy. During the operation, the largest splenic artery aneurysm was found to be adhered to the pancreas too tightly to ablate. It initially appeared that pancreatectomy would be necessary, but considering the associated risk of postoperative complications, we tried to avoid this. Thus, we cut open the aneurysm and excised it, leaving the anterior wall which was adhered to the pancreas. Our procedure proved the best way to preserve the pancreas and eliminate further aneurysmal formation.