Bacteraemia and seeding of capsulate Bacteroides spp. and anaerobic cocci

Abstract

Summary. The effect of capsulation on the ability of Bacteroides fragilis, B. asaccharolyticus and anaerobic gram-positive cocci to induce bacteraemia and seeding to various organs was investigated. The test species were injected into mice subcutaneously alone, or mixed with other aerobic or facultative organisms. Capsulate anaerobes were isolated more frequently from the blood, spleen, liver, and kidneys of infected animals than were non-capsulate organisms. After injection of single anaerobic strains, capsulate organisms were recovered from 163 (39%) of 420 animals; non-capsulate anaerobes were recovered from only 14 (3%) of 420 animals. After injection of B. fragilis mixed with aerobic or facultative organisms, the capsulate B. fragilis strain was isolated more often and for longer periods than the non-capsulate strain. Capsulate B. fragilis was also recovered more often 5 days after injection with other organisms, than when injected alone. These data demonstrate that capsulate Bacteroides spp. and anaerobic gram-positive cocci are more virulent than noncapsulate strains in single and mixed infections.

Gram-positive anaerobic cocci – commensals and opportunistic pathogens

“…The demonstration of synergy with facultative and anaerobic bacteria during the growth of abscesses, capsule formation and the ability to form hydrogen sulphide from glutathione have been described as important virulence factors (Brook & Walker, 1985;Brook, 1987Brook, , 1988aCarlsson et al, 1993). The demonstration of synergy with facultative and anaerobic bacteria during the growth of abscesses, capsule formation and the ability to form hydrogen sulphide from glutathione have been described as important virulence factors (Brook & Walker, 1985;Brook, 1987Brook, , 1988aCarlsson et al, 1993).…”

“…Parvimonas micra is one of the best studied of the GPAC in terms of characterisation of its virulence factors. The demonstration of synergy with facultative and anaerobic bacteria during the growth of abscesses, capsule formation and the ability to form hydrogen sulphide from glutathione have been described as important virulence factors (Brook & Walker, 1985;Brook, 1987Brook, , 1988aCarlsson et al, 1993). Furthermore, it has been described to adhere to gingival epithelial cells (Dzink et al, 1989) and to express immunoglobulin Fc-binding proteins (Grenier & Michaud, 1994).…”

Gram-Positive Anaerobic Cocci

“…In 1958, Mergenhagen et al (178) reported synergy between "anaerobic streptococci" and S. aureus in causing progressive gangrene in rabbits; neither component was effective on its own, but cells of S. aureus could be replaced by a dialyzable cell filtrate of S. aureus. This work was extended in the 1980s by Brook and coworkers (18,19,25,47,48), who used a subcutaneous abscess model in the mouse. They demonstrated synergy of GPAC with facultative and anaerobic bacteria, including S. aureus, P. aeruginosa, several species of streptococci and members of the Enterobacteriaceae, in their ability to induce abscesses, enhance the growth of bacterial components, and increase mortality (19,25).…”

“…This work was extended in the 1980s by Brook and coworkers (18,19,25,47,48), who used a subcutaneous abscess model in the mouse. They demonstrated synergy of GPAC with facultative and anaerobic bacteria, including S. aureus, P. aeruginosa, several species of streptococci and members of the Enterobacteriaceae, in their ability to induce abscesses, enhance the growth of bacterial components, and increase mortality (19,25). These studies examined recent clinical isolates of P. anaerobius, P. asaccharolyticus, P. magnus, P. micros, and P. prevotii; they did not demonstrate clear differences between species of GPAC, but small numbers of strains were examined.…”

Phagocytosis of bacterial strains isolated from acute dentoalveolar abscess

“…intermedia (6), Pr. oralis (5) and F. nucleaturn (6). All isolates were lyophilised within three subcultures of primary isolation.…”