Isolation of Streptobacillus moniliformis from the middle ear of rats.

Streptobacillus moniliformis was isolated from the middle ear of 9 of 16 rats used for otological studies. Examination of rat sera for the presence of anti-Streptobacillus moniliformis antibodies using an ELISA technique resulted in 15 seropositive animals. The source of the S. moniliformis infection was not determined.     

Complete genome sequence of Streptobacillus moniliformis type strain (9901)

Streptobacillus moniliformis Levaditi et al. 1925 is the type and sole species of the genus Streptobacillus, and is of phylogenetic interest because of its isolated location in the sparsely populated and neither taxonomically nor genomically much accessed family 'Leptotrichiaceae' within the phylum Fusobacteria. The 'Leptotrichiaceae' have not been well characterized, genomically or taxonomically. S. moniliformis,is a Gram-negative, non-motile, pleomorphic bacterium and is the etiologic agent of rat bite fever and Haverhill fever. Strain 9901(T), the type strain of the species, was isolated from a patient with rat bite fever. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is only the second completed genome sequence of the order Fusobacteriales and no more than the third sequence from the phylum Fusobacteria. The 1,662,578 bp long chromosome and the 10,702 bp plasmid with a total of 1511 protein-coding and 55 RNA genes are part of the Genomic Encyclopedia of Bacteria and Archaea project.     

Streptobacillus moniliformis isolated from otitis media of conventionally kept laboratory rats.

Streptobacillus moniliformis (Sm) was isolated from the middle ear of two inbred albino rats (strain CAP/Kuv) suffering from murine respiratory mycoplasmosis and purulent bilateral otitis media. The animals were kept under conventional conditions and used for immunological studies. The biochemical pattern of the isolate was identical with that of four other Sm strains of different origin but differed in its ability to lyse erythrocytes in sheep blood agar. This is the first Sm strain with hemolysis described. Pathogenicity of the strain was demonstrated in C57BL/6Han mice known to be susceptible to streptobacillosis. Three of five mice inoculated orally developed characteristic signs of a septic lymphadenitis. In the homologous system and with Sm strain ATCC 49567 as antigen, all five sera showed positive titers in the indirect immunofluorescence assay. Possible improvements in the diagnosis and the role of this "forgotten pathogen" in laboratory animal medicine are discussed.     

Detection of antibodies to Streptobacillus moniliformis in rats by an immunoblot procedure

An immunoblot (IB) technique for detecting antibodies to Streptobacillus moniliformis in rat sera was evaluated. Immune sera to three S. moniliformis strains showed a similar reactivity pattern with both autologous and homologous antigens in the 18-87 kDa range. Using a rat S. moniliformis strain as the antigen, a similar reactivity pattern was found with sera from rats infected experimentally with S. moniliformis and sentinels. Two to five proteins were detected in the 32-55 kDa range. Over a period of 2.5 years, 27/133 rat serum panels submitted for routine monitoring yielded one or more S. moniliformis enzyme-linked immunosorbent assay (ELISA)-positive samples. In one of these 27 panels, sera showed an IB reactivity pattern resembling that observed with immune sera and with sera from infected and exposed rats. S. moniliformis was confirmed in the colony by both culture and polymerase chain reaction (PCR). Sera from the remaining 26 ELISA-positive serum panels frequently showed activity to a 57 kDa antigen but not more than one antigen was detected in the 32-55 kDa range. We conclude that the IB can be used as a confirmatory test for the detection of S. moniliformis infection in ELISA-positive rats.     

不同品系小鼠对实验感染念珠状链杆菌敏感性的观察

本文通过念珠状链杆菌（Ｓｔｒｅｐｔｏｂａｃｉｌｕｓｍｏｎｉｌｉｆｏｒｍｉｓ,Ｓ．ｍ．）实验感染昆明、Ｃ５７ＢＬ／６Ｊ、ＢＡＬＢ／ｃ、ＩＣＲ、ＮＩＨ、ＤＢＡ共６个品系小鼠,观察其对Ｓ．ｍ．敏感性的差异。其中昆明、Ｃ５７ＢＬ／６Ｊ两个品系在腹腔接种后表现出明显的临床、病理改变。昆明小鼠发病率和死亡率分别为９２％和８０％;Ｃ５７ＢＬ／６Ｊ分别是８０％和１２％。昆明小鼠较之Ｃ５７ＢＬ／６Ｊ小鼠起病急、病情严重,多数动物死于感染的急性期。其余品系的发病率为：ＮＩＨ８％、ＢＡＬＢ／ｃ和ＤＢＡ４％,没有动物死亡;ＩＣＲ在接种后无任何临床病理改变。在实验感染后临床病理改变方面,昆明小鼠和Ｃ５７ＢＬ／６Ｊ小鼠间有较大不同。昆明小鼠以末梢血管淤血、四肢尾部水肿、关节炎、截瘫、腹泻为主,而Ｃ５７ＢＬ／６Ｊ小鼠则以注射部位和其它部位皮下脓肿、化脓性关节炎为主。本研究提示,中国昆明小鼠对Ｓ．ｍ．敏感性最高,可以将其作为“哨兵动物”用于实验大鼠Ｓ．ｍ．的常规监测;不同品系小鼠不仅对实验感染Ｓ．ｍ．的敏感性不同,而且表现出不同的临床病理改变。     

Streptobacillus moniliformis epizootic in barrier-maintained C57BL/6J mice and susceptibility to infection of different strains of mice

We report a Streptobacillus moniliformis epizootic in barrier-maintained SPF mice. Although various inbred and F1 hybrid strains of mice have been kept in this animal facility, only C57BL/6J Han [corrected] mice showed clinical signs of disease. During the course of the epizootic, 825 breeding animals (approximately 36% of the breeders) died or had to be killed because of severe clinical signs. Although sequential treatment with ampicillin and chlortetracycline gave good therapeutic results, the animal facility was vacated in order to exclude any risk of cross-contamination of the other rodent colonies in our institute. The source and route of transmission of S. moniliformis could not be elucidated. To investigate strain dependent differences experimental infection of different strains of mice with our S. moniliformis isolate was performed. After oral infection only C57BL/6J showed the typical signs of a cervical lymphadenitis and gave an immunological response. BALB/cJ, C3H/He, DBA/2J, CB6F1 and B6D2F1 mice were not affected except in two cases of DBA/2J and B6D2F1 mice where seroconversion was observed. After intravenous infection of C57BL/6J, DBA/2J [corrected] and BALB/cJ all animals showed positive titers in the indirect immunofluorescence test (IIF). One hundred percent of the C57BL/6J, forty percent of the DBA/2J, and none of the BALB/cJ mice developed severe symptoms. The results demonstrate that the susceptibility to streptobacillosis is predominantly influenced by genetic factors.     

PCR for the detection and typing of campylobacters

The flaA gene of Campylobacter sp. was amplified using PCR. Primers were chosen which amplified 1.3 kb of the flaA gene in Camp. jejuni and Camp. coli. 'Campylobacter upsaliensis' amplimer was approximately 1.7 kb in size and was easily distinguishable. Other species of campylobacter failed to yield amplimer. The amplimer was digested with Alu 1 which demonstrated considerable restriction fragment length polymorphism and should allow the development of a rapid novel typing scheme which does not rely on previous culture of campylobacter strains.     

Comparative analysis of clinics,pathologies and immune responses in BALB/c and C57BL/6 mice infected with Streptobacillus moniliformis

Streptobacillus (S.) moniliformis is a rat-associated zoonotic pathogen that occasionally causes disease in other species. We investigated the working hypothesis that intranasal infection might lead to different immune responses in C57BL/6 and BALB/c mice associated with distinct pathologies. This study confirmed with 75% mortality the known high susceptibility of C57BL/6 mice to Streptobacillus moniliformis infection in comparison to BALB/c mice which did not develop signs of disease. Main pathologies in C57BL/6 mice were purulent to necrotizing lymphadenitis and pneumonia. Significant seroconversion was recorded in surviving mice of both strains. Differentiation of IgG-subclasses revealed mean ratios of IgG2b to IgG1 below 0.5 in sera of all mice prior to infection and of BALB/c mice post infection. In contrast, C57BL/6 mice had a mean IgG2b/IgG1 ratio of 2.5 post infection indicating a Th1 immune response in C57BL/6 versus a Th2 response in BALB/c mice. Evaluation of different sentinel systems revealed that cultural and serological investigations of these animals might not be sufficient to detect infection. In summary, an intranasal S. moniliformis infection model in C57BL/6 mice leading to purulent to necrotizing inflammations in the lung, the lymph nodes and other organs associated with a Th1 immune response is described.