We have cloned the chromosomal hemolysin determinants from Escherichia coli strains belonging to the four O-serotypes O4, O6, O18, and O75. The hemolysin-producing clones were isolated from gene banks of these strains which were constructed by inserting partial Sau3A fragments of chromosomal DNA into the cosmid pJC74. The hemolytic cosmid clones were relatively stable. The inserts were further ...

The alpha-hemolytic Escherichia coli strain C134-73 Hly+ was primarily cytocidal to human blood monocytes and granulocytes in vitro in the presence of fresh autologous plasma. Monocytes and granulocytes underwent marked morphological changes during incubation with the bacteria, and the percentages of intact phagocytes decreased progressively with the time of incubation. The cytotoxic effect inc...

Complement-mediated lysis of sheep erythrocytes coated with optimal concentrations of rabbit IgG hemolysin was inhibited by euglobulin fractions from the sera of patients with seropositive rheumatoid arthritis. That this was due to direct interaction with the IgG coat on the red cell rather than a nonspecific reaction with complement in the fluid phase was confirmed by controls using cells coat...

Escherichia coli hemolysin, a transmembrane pore-forming exotoxin, is considered an important virulence factor for E. coli-related extraintestinal infections and sepsis. The possible significance of hemolysin liberation for induction of inflammatory lipid mediators was investigated in isolated rabbit lungs infused with viable bacteria (concentration range, 10(4)-10(7)/ml). Hemolysin-secreting E...

M a n y mouse strains become immunocompetent to erythrocyte antigens during the 1st wk of life (1, 2). However, in vivo experimental techniques have, to date, been unable to answer the question as to where components of precursor units capable of interact ing with erythrocyte antigens first arise. Using the modified Marbrook tissue culture technique (3, 4), we have under taken a s tudy of the k...

Staphylococcus aureus, a Gram-positive bacterium is pathogenic in nature. It is known that secreted toxins remain active after antibiotic treatment. The alpha hemolysin or alpha toxin damages cell membrane and induces apoptosis and degradation of DNA. The titer of alphahemolysin increases and causes hemostasis disturbances, thrombocytopenia, and pulmonary lesions during staphylococcal infection...

Associations between known or putative virulence factors of Shiga toxin-producing Escherichia coli and disease in humans were investigated. Univariate analysis and multivariate logistic regression analysis of a set of 237 isolates from 118 serotypes showed significant associations between the presence of genes for intimin (eae) and Shiga toxin 2 (stx2) and isolates from serotypes reported in hu...

A microtiter procedure for the quantitation of Bacillus cereus hemolysin is described.

Antibodies against delta-haemolysin from Staphylococcus strain CN4108 (Newman) did not neutralise delta-haemolysin from the canine strain of S. aureus CN7450 to the same extent as delta-haemolysin prepared from S. aureus strain CN4108. This is additional evidence for the immunological distinctness of delta-haemolysin from these two S. aureus strains of human and canine origin.

38, 6th ASM Conference on Streptococcal Genetics, Ashville, NC, USA]. GBS β-h/c contributes to virulence in animal studies. When administered to neonatal rats via the pulmonary route, NH GBS mutants possess a 1000-fold greater LD50 than the wild-type parent strains, confirming a role in the pathogenesis of pneumonia and systemic spread [52]. In an adult mouse model of GBS arthritis, hemolysin e...