Protein and antigenic heterogeneity among isolates of Bacillus piliformis

Dual effects of PFOA or PFOS on reductive dechlorination of trichloroethylene (TCE)

PFASs and chlorinated solvents are the common co-contaminants in soil and groundwater at firefighter training areas (FTAs). Although PFASs mixtures could have adverse impacts on bioremediation of trichloroethylene (TCE) by inhibiting Dehalococcoides (Dhc), little is known about the effect and contribution of PFOA or PFOS on dechlorination of TCE by non-Dhc organohalide-respiring bacteria (OHRB). To study this, PFOA and PFOS were amended to the growth medium of a non-Dhc OHRB-containing enrichment culture to determine the impact on dechlorination. This study demonstrated that high levels of PFOA or PFOS (100 mg L^-1) inhibited TCE dechlorination in four non-Dhc OHRB-containing community including Geobacter, Desulfuromonas, Desulfitobacterium, and Dehalobacter, but low levels of PFOA or PFOS (≤10 mg L^-1) enhanced TCE dechlorination. Four non-Dhc OHRB were less inhibited by PFOA than that by PFOS, and high level of PFOS killed Desulfitobacterium and Dehalobacter and decreased the biodiversity of bacterial community. Although most fermenters were killed by the presence of 100 mg L^-1 PFOS, two important co-cultures (Desulfovibrio and Sedimentibacter) of OHRB were enriched, indicating that the syntrophic relationships between OHRB and co-cultures still remained, and PFOA or PFOS inhibited TCE dechlorination by directly repressing non-Dhc OHRB. Our results highlight that the bioattenuation of chloroethene contamination could be confounded by non-Dhc OHRB in high levels of PFOS contaminated subsurface environments at FTAs.

Implications of infectious agents on results of animal experiments

Report of the Working Group on Hygiene of the Gesellschaft für Versuchstierkunde–Society for Laboratory Animal Science (GV-SOLAS)

GV-SOLAS Working Group on Hygiene: Werner Nicklas (Chairman), Felix R. Homberger, Brunhilde Illgen-Wilcke, Karin Jacobi, Volker Kraft, Ivo Kunstyr, Michael Mähler, Herbert Meyer & Gabi Pohlmeyer-Esch

Tyzzer's disease in foals: retrospective studies from 1969 to 2010

Reports of 148 cases of Tyzzer's disease in foals in central Kentucky were analyzed to identify features of the disease and factors associated with it. The records indicate that Tyzzer's disease is a rapidly progressive, highly fatal hepatitis caused by Clostridium piliforme. Common clinical findings are lethargy, fever, anorexia, and icterus. Seizures, coma, and death may rapidly ensue. Laboratory findings are leukopenia, metabolic acidosis, hypoglycemia, and increased activity of hepatic enzymes. Diagnosis is primarily based on clinical signs and postmortem findings but a polymerase chain reaction (PCR) is now available to detect C. piliforme DNA in organs and feces. Disease occurred most frequently in foals between 9 and 30 days of age that were born in April to May and was associated with heavy rainfall in the spring and high protein and nitrogenous diets fed to nursing mares. The findings are consistent with the ingestion of C. piliforme in the feces of adult horses and overgrowth in the intestine of foals with a high level of nutrients in their intestine.

Evaluation of available diagnostic methods for Clostridium piliforme in laboratory rabbits (Oryctolagus cuniculus)

Recent literature has indicated that animals seropositive for Clostridium piliforme may have negative findings on polymerase chain reaction (PCR) testing. This study examines and reports on the results of serology, PCR and histopathology tests performed on a group of 20 laboratory rabbits seropositive for C. piliforme using the latest available diagnostic methodologies. The presence of the organism was not confirmed by either PCR or histopathology in this group of 20 for C. piliforme seropositive rabbits. This presents challenges for laboratory animal veterinarians and scientists wishing to establish the presence of the organism with commonly available diagnostic methods and means that clinical signs of disease in addition to diagnostic results must be interpreted together.

Tyzzer's disease in a Eurasian otter (Lutra lutra) in Scotland

A Eurasian otter (Lutra lutra) cub found in weak condition on the Isle of Harris, Scotland, developed bilateral corneal oedema 16 days after being admitted to a rehabilitation centre. It died unexpectedly on day 26. On postmortem examination, there was excess clear fluid in the body cavities and the liver was swollen with numerous pale focal lesions and petechial haemorrhages throughout. Histopathological examination revealed bundles of bacilli morphologically typical of Clostridium piliforme within hepatocytes. Comparative analysis of the nucleotide base sequence of a 16S rdna fragment amplified from the infected liver tissue revealed that it was identical to a C piliforme 16S rdna sequence. The possibility of concurrent infection with canine adenovirus type 1 was considered but none of the characteristic histopathological lesions was observed and examination of the liver by transmission electron microscopy was negative for virus particles. This appears to be the first record of Tyzzer's disease in an otter and the first in a wild animal in Britain.

Tyzzer's disease in an 11-day-old foal

An 11-day-old pony became depressed, anorectic, and pyrexic 2 days after the topsoil of its paddock had been turned over. Rapid progression to colic and head pressing occurred, despite intensive therapy for Tyzzer's disease, and the foal died within 7 h of the appearance of central nervous system signs.

Effects of neutrophil, natural killer cell, and macrophage depletion on murine Clostridium piliforme infection

Clostridium piliforme infection (Tyzzer's disease) induces enterohepatic disease in many domestic and laboratory animals. Murine susceptibility to Tyzzer's disease varies with host strain, age, and immune status However, little is known about the role of the immune system in control of this disease. To investigate the role of host immunity in Tyzzer's disease, mice were depleted of either neutrophils, natural killer cells, or macrophages by antibody administration or chemotherapy. After depletion, DBA/2 mice, which are naturally susceptible to C. piliforme, or naturally resistant C57BL/6 mice were inoculated intravenously with C. piliforme. Animals were euthanized 3 days postinoculation and evaluated for gross and histologic lesions and hepatic bacterial load. In juvenile DBA/2 or C57BL/6 mice, depletion of either neutrophils or natural killer cells increased severity of disease. In adult mice, depletion of natural killer cells significantly increased severity of Tyzzer's disease in the resistant (C57BL/6) but not in the susceptible (DBA/2) strain. Macrophage depletion did not alter the course of infection in either mouse strain. These studies indicate an important role for neutrophils and natural killer cells in the pathogenesis of murine Tyzzer's disease. The role of macrophages in murine C. piliforme infection will require further evaluation.

Bacillus piliformis infection (Tyzzer's disease) in a patient infected with HIV-1: confirmation with 16S ribosomal RNA sequence analysis

Bacillus piliformis is a long, rod-shaped bacterium that has never been grown in cell-free medium and whose taxonomic classification is uncertain. B. piliformis is the causative agent of Tyzzer's disease, which is frequently reported in laboratory, wild, and domesticated animals. The spectrum and severity of this disease is wide in animals. Although many infections are rapidly fatal, subclinical infections are also common. To date, there have been no reports of B. piliformis infection in human beings, although elevated antibody levels have been reported in pregnant women. We describe the first case of human B. piliformis infection, in a man with HIV-1 infection and chronic, localized, crusted verrucous lesions. The diagnosis was confirmed by ribosomal RNA sequencing. The spectrum of organisms leading to infection and the spectrum of diseases caused by these organisms continue to expand, as new infections are identified and as patients with HIV-1 live longer with more severe immune suppression. The extreme difficulty in culturing B. piliformis and the lack of clinical and histopathologic experience with this organism in human beings mean that B. piliformis is potentially another infectious agent to be considered in human beings. Also, when an infectious organism is a strong clinical consideration, silver stains may be of use when results of routine bacterial staining are negative.

Seroanalysis of Tyzzer's disease in horses: implications that multiple strains can infect Equidae

A monoclonal antibody based competitive inhibition assay was used to detect antibodies in horse sera to purified flagellar antigens from distinct Clostridium piliforme isolates. Sequential absorption of hyperimmune rat serum to C. piliforme isolate E (horse-origin isolate), a positive C. piliforme-immune horse serum, and other suspected immune horse sera with unrelated bacteria or C. piliforme isolates E or isolate R1 (rat-origin isolate) alone demonstrated the specificity of this assay for C. piliforme. This specificity was associated with the inhibition of monoclonal antibody binding to C. piliforme flagella, rather than to C. piliforme somatic antigens, by horse immunoglobulins partially purified from serum. Thirty seven of 162 horse sera possessed large amounts of antibody to the flagella of C. piliforme isolate E and 23 of the 162 had large amounts of antibody to the flagella of C. piliforme isolate R1; 9 of the sera possessed large amounts of antibody to both flagellar antigens. Absorption of these sera with isolate E or R1 demonstrated that antibody reactivity to the 2 C. piliforme isolates was isolate-specific and not due to antibody cross-reactive with both isolates. These results suggest that infection of horses with C. piliforme may be relatively common; and that they are susceptible to at least 2 distinct strains.

In vitro model of adhesion and invasion by Bacillus piliformis

An in vitro model of Bacillus piliformis infection was developed to investigate the mechanisms of adhesion and internalization of this obligate intracellular bacterium. Adhesion and internalization events were examined by electron microscopic evaluation of infected Caco-2 cell monolayers. A few bacteria were identified in apical surface invaginations and in vacuoles subjacent to the apical surface, whereas the majority of bacteria were observed free within the cytoplasm, suggesting that B. piliformis entered epithelial cells via a phagocytic process and rapidly escaped the phagosome. To confirm that host cell phagocytosis was involved in entry of B. piliformis into mammalian cells, Intestine 407 cells were treated with the phagocytic inhibitor cytochalasin D, infected with B. piliformis, and evaluated for bacterial internalization by double-fluorescence labeling. The results showed decreased intracellular bacteria, suggesting that internalization was dependent on host cell microfilament function. To examine the role of B. piliformis in internalization, growth of live and Formalin-killed bacteria was compared. Dead bacteria were not internalized, suggesting that B. piliformis actively participates in internalization. B. piliformis appears to enter host cells by a bacterially directed phagocytic process. The in vitro system described should prove invaluable in further investigations of B. piliformis pathogenic mechanisms.

Bacillus piliformis flagellar antigens for serodiagnosis of Tyzzer's disease

Purified flagella from multiple isolates of Bacillus piliformis were obtained and examined by electron microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot (immunoblot) analyses were used to assess the purity, antigenicity, and cross-reactivity of purified flagellar preparations. SDS-PAGE demonstrated a single, major protein band evident at approximately 53 to 56 kDa in all isolates tested. Results of Western blot analyses indicated a lack of cross-reactivity between flagellar antigens and heterologous isolates. Enzyme-linked immunosorbent assays (ELISAs) were used to compare the efficacies of flagellar preparations from the various isolates as antigens in detecting B. piliformis serum antibodies from several host species. ELISA results indicated that no single flagellar preparation could be relied on to consistently identify serum antibodies in all the host species tested; however, ELISAs that utilized a trivalent flagellar antigen preparation were shown to be specific and sensitive for the detection of antibodies to B. piliformis.