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At least 145 records · Page 8Linked to original sources
PubMed1991

Early events after intra-abdominal infection with Bacteroides fragilis and Escherichia coli.

Growth of Bacteroides fragilis and Escherichia coli was monitored during early stages of single (mono-) and mixed intra-abdominal infection in a rat fibrin clot model. When B. fragilis and E. coli were together involved in the infection, B. fragilis numbers increased about 6 h after an initial decline. This increase was not found with B. fragilis mono-infections. The numbers of E. coli increased rapidly in both mono- and mixed infections and stayed high for several days, but only mixed infection resulted in abscesses that persisted for more than 7 days. Macrophages, the main component of the peritoneal cellular defence mechanism, were outnumbered by polymorphonuclear leucocytes during the first 6 h of infection. Further characterisation of the macrophage population by means of monoclonal antibodies showed a shift from resident to exudate macrophages as the result of influx of the latter.

Abdomen↗
PubMed1987

Studies on bacterial synergism in mice infected with Bacteroides intermedius and Fusobacterium necrophorum.

This study was undertaken to characterize the kinetics of possible bacterial synergy using a mouse model of mixed intraabdominal infection with Bacteroides intermedius and Fusobacterium necrophorum. Female CD-1 mice were injected intraperitoneally with B. intermedius, F. necrophorum or mixtures of both organisms. Generalized septic peritonitis developed within 24 hr, with abscess formation occurring after one to two wk in survivors with the mixed infection. Involvement of the reticuloendothelial system was evidenced by dose-dependent hepatosplenomegaly, which appeared during the first wk postinfection and progressed throughout the course of the experiment. Indirect immunofluorescence confirmed the presence of both species of bacteria in frozen sections of liver tissue. The median lethal dose (LD50) was 2.11 x 10(9) for the mixture, 3.03 X 10(9) for B. intermedius alone, and 1.07 X 10(9) for F. necrophorum alone. The median abscess-producing dose (AD50), the dose required to produce abscesses in fifty percent of the surviving mice at two wk, was approx. 1/100 of the LD50 dose. The AD50 for intrahepatic abscesses was 2.8 x 10(8) for the mixture, whereas the AD50 for intraabdominal abscesses occurring in any site was 5.14 X 10(7). Both Bacteroides and Fusobacterium persisted in tissue for at least 22 wk following mixed infection. The persistence of the Bacteroides in tissue represents a synergistic result of mixed infection with Fusobacterium and contributed to the chronicity of intraabdominal abscess formation. Bacteroides, injected alone, did not produce abscesses at any of the doses tested. However, when passaged (isolated from mixed infection hepatic abscesses) B. intermedius was used, the bacteria did induce abscesses.

Abscess↗
PubMed1978

The occurrence, prevalence and transmission of Bacteroides nodosus infection in cattle.

Following reports of findings of ovine foot-rot flora in the feet of cattle, a study was undertaken to determine the prevalence of Bacteroides nodosus infection in the apparently normal cattle population. We found that 34.5 to 74.2 per cent of the animals examined on different farms had B nodosus present in one or more feet. B nodosus was not the most prevalent bacterium observed in smears from cattle. Other Gram negative species including Fusiformis necrophorus and many Gram positive cocci and coccobacilli were also present. Macroscopic lesions in the interdigital skin characterised by erosion and hyperkeratosis were usually associated with the occurrence of B nodosus. B nodosus isolated from cattle induced mild interdigital dermatitis in experimental cattle and sheep and the infection was transmitted to recipient cattle and sheep under field conditions. Virulent foot-rot of sheep was not transmitted to recipient cattle in conditions where the disease spread to susceptible sheep.

Animals↗
PubMed1978

Serological diagnosis of Bacteroides fragilis infections by a complement fixation test.

Paired specimens of serum from patients from whom Bacteroides fragilis had been isolated were tested by complement fixation against a crude B. fragilis antigen. A high titre or a rise in titre to B. fragilis was obtained in each of five patients with infection after abdominal surgery but in none of 11 patients with postpartum pyrexia nor in nine with vaginitis.

Abdomen↗
PubMed1984

Detection of specific bacterial antigen in urine of patients infected with Bacteroides fragilis.

An indirect enzyme-linked immunosorbent assay was developed to detect specific Bacteroides fragilis antigen(s) in human urine. Specimens collected within 72 hr of a positive culture were centrifuged, dialyzed, and treated with Tween 20, polyethylene glycol, and bovine serum albumin. Goat hyperimmune gamma-globulin to B. fragilis strain ATCC 23745 was added and incubated, and supernatants were tested for antibody activity to polysaccharide-protein antigen of the same organism. Mean +/- SD results, reported as percentage inhibition of control values and interpreted blindly, were as follows: 29 normal subjects, 9.8% +/- 6.0%; 22 patients with Enterobacteriaceae bacteremia, 6.0% +/- 5.1%; six patients with nonbacteremic infections due to B. fragilis, 22.3% +/- 10.3%; and nine patients with B. fragilis bacteremia, 28.7% +/- 10.2%. Three of six nonbacteremic patients and eight of nine bacteremic patients yielded values greater than 2 SD of control values. None of 22 patients with Enterobacteriaceae bacteremia was falsely positive (specificity, 100%).

Antigens, Bacterial↗
PubMedDate not supplied

[The body's nonspecific resistance factors in a localized experimental infection caused by Bacteroides].

Under local experimental infection induced by bacteroides of Fragilis group the factors of nonspecific organism resistance take an active part in the inflammation process. Phase changes of the state of monocytic-phagocytic and complement systems were observed. Peripheral blood leukocyte phagocytic activity decreased at the primary stage, then followed the complement activation by the alternative pathway mainly. The increase of phagocytic and metabolic activities of those phagocytes taking part in the inflammation, the complement at this stage is activated due to the classical pathway while being at the stage of clinic manifestation. Levels of antibody titres are also increasing.

Animals↗
PubMedDate not supplied

Penetration of cephalothin and cefoxitin into experimental infections with Bacteroides fragilis.

The in vitro activities of cephalothin and cefoxitin against Bacteroides fragilis were studied by time-kill curves and measurement of residual drugs in culture supernatants. Cefoxitin was bactericidal, causing a decrease of 10(7) in viable counts over 24 hr. Cephalothin caused an initial decrease of 10(2) B. fragilis at 2 hr; this change was followed by growth of the organism within 24 hr back to the number present before addition of cephalothin. The concentration of cephalothin in broth decreased rapidly within 2 hr and was undetectable within 24 hr, whereas the level of cefoxitin decreased only 25% over the 24-hr period. Penetration of these drugs into perforated ping pong balls implanted intraperitoneally in rabbits was studied. Three weeks after implantation the reservoirs were infected with B. fragilis. After intramuscular administration of five doses of antibiotic, the penetration of cephalothin, as measured by bioassay, in uninfected and infected capsules was 16% and 2%, respectively, of the peak serum concentration; similar findings were noted with cefoxitin. For determination of the rate of breakdown within the infected site, radiolabeled antibiotic was injected into the capsule, and the concentrations of bioactive and radioactive drug were determined. With radiolabeled cephalothin there was a rapid decrease in bioactivity during the initial 60 min, and no active drug was measurable after 2 hr. In contrast, only 40% of cefoxitin was inactivated at the end of 6 hr. The results indicate that levels of cephalothin and cefoxitin are reduced significantly in sites infected with B. fragilis. The decrease appears to be mediated by both a decrease in penetration and inactivation at the site of infection.

Animals↗
PubMed1977

[Therapy for severe anaerobic infections with clindamycin (author's transl)].

Ten adult patients with severe Bacteroides infections were treated with 0.9 approximately 1.8 g/day of parenteral or oral clindamycin, and a child was treated with 0.3 g/day orally. Remarkable responses and cures were obtained in all the patients, who had no underlying diseases and pure anaerobic infections; a case of sepsis, two cases of liver abscess, a case of subcutaneous abscess and a case of spinal epidural abscess. The other six patients who had ultimately fatal underlying diseases or mixed infections did not respond well to the combination of clindamycin and the other antibiotics therapy, althought bacteriological cures were obtained in all but two cases. Clindamycin was well tolerated and generally nontoxic, nevertheless it was administrated for long term (34 approximately 49 days). But transient development of transaminase was seen in a patient. The data suggested that clindamycin should be considered a first choice antibiotic for the treatment of an aerobic, especially, Bacteroides infections.

Abscess↗
PubMed1989

Experimental infections by Bacteroides gingivalis in non-immunized and immunized rabbits.

The interactions between Bacteroides gingivalis and systemic antibodies were studied in tissue cages implanted in the backs of New Zealand white rabbits. Infectivity was evaluated according to clinical signs and to leukocyte and bacterial counts in material aspirated from the tissue cages. Pre- and post-inoculation antibody levels to sonicated whole bacterial cells were determined by enzyme-linked immunosorbent and agar immunodiffusion assays. Rabbits immunized against B. gingivalis and then challenged with pure cultures of B. gingivalis revealed complete elimination or markedly lower postinoculation bacterial counts and considerably weaker tissue reactions than non-immunized animals. B. gingivalis co-inoculated with Actinobacillus actinomycetemcomitans caused significantly more severe infections than observed in monoinfected animals. The present results suggest that the immune system acting through systemic antibodies and/or cellular mechanisms may modulate the pathogenic potential of infecting periodontal pathogens.

Animals↗
PubMed1982

Comparative efficacy of 10 antimicrobial agents in experimental infections with Bacteroides fragilis.

The comparative efficacy of 10 antimicrobial agents against 15 strains of Bacteroides was examined in vivo using an experimental model of subcutaneous abscesses in mice. Results were evaluated by bacterial counts per lesion with the antimicrobial agents administered beginning 1 hr after challenge. Six drugs reduced counts (mean +/- SEM log decrease) significantly compared with values in untreated control animals: metronidazole, 6.7 +/- 0.6; clindamycin, 5.0 +/- 0.6; moxalactam, 3.8 +/- 0.5; cefoxitin, 3.5 +/- 0.5; chloramphenicol, 1.6 +/- 0.5; and carbenicillin, 1.0 +/- 0.3. Antimicrobial agents that had no significant effect compared with values in untreated control animals were cephalothin, cefoperazone, ceforanide, and rosaramicin. Evaluation of several parameters based on in vitro activity and pharmacokinetic properties at the infected site indicated that the time during which the level of antimicrobial agent exceeded the minimal inhibitory concentration correlated best with in vivo antibacterial activity. A delay in the time that treatment was initiated resulted in a marked reduction in in vivo activity.

Abscess↗
PubMed2003

The influence of experimental Bacteroides fragilis infection on substance P and somatostatin-immunoreactive neural elements in the porcine ascending colon - a preliminary report.

The present study was aimed at disclosing the influence of Bacteroides fragilis (one of the most important bacterial agents causing colitis in children) experimental infection on the expression of substance P (SP) and somatostatin (SOM) in neurons and nerve fibres within the porcine ascending colon. Distinct differences in the distribution pattern of neural elements immunoreactive to the substances studied were observed between the experimental (Inflam) and control (Contr) pigs. In general, the number of SP-IR neurons and nerve terminals increased, while the expression of SOM decreased after Bacteroides fragilis-induced colitis (BFIC). However, distinct differences in the intensity of these alterations were observed between particular compartments of the bowel segment studied. Thus, the present results suggest that SP- and SOM-immunoreactive (SOM-IR) elements of the enteric nervous system play a part in the control of colonic activity during BFIC.

Animals↗