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Abstract 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.

Background. In situ hybridization (ISH) with high sensitivity has been requested to demonstrate hepatitis C virus (HCV) RNA in formalin-fixed, paraffin-embedded (FFPE) sections of the liver. Methods. ISH employing a locked-nucleic-acid- (LNA-)modified oligonucleotide probe and biotin-free catalyzed signal amplification system (CSAII) was applied to HCV-RNA detection in the liver tissue. Nested reverse-transcription polymerase chain reaction (RT-PCR) was performed for HCV genotyping using total RNA extracted from FFPE sections. The target tissues included FFPE tissue sections of humanized livers in HCV-infected chimeric mice (HCV genotypes 1a, 1b, and 2a and noninfected) and of needle-biopsied livers from HCV-infected patients. Results. HCV-RNA was demonstrated with the ISH technique in HCV-infected liver tissues from both chimeric mice and 9 (82%) of 11 patients with HCV infection. The HCV signals were sensitive to RNase. Nested RT-PCR confirmed the genotype in 8 (73%) of 11 livers (type 1b: 6 lesions and type 2a: 2 lesions). HCV-RNA was not identified in chronic hepatitis B lesions, fatty liver, autoimmune hepatitis, and hepatocellular carcinoma. Conclusion. ISH using the LNA-modified oligonucleotide probe and CSAII was applicable to detecting HCV-RNA in routinely prepared FFPE liver specimens.