[Bacterial spontaneous empyema: infrequent complication of liver cirrhosis].
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Aged↗
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Results for “BACTEROIDES INFECTIONS”
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Anaerobic meningitis in children.
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Adolescent↗
Experimental intraabdominal abscess formation by Escherichia coli and bacteroides fragilis.
An improved animal model of intraperitoneal abscess formation was developed in order to study the role of Bacteroides fragilis and Escherichia coli. Both microorganisms were found to independently cause abscesses, although Bacteroides fragilis-induced abscesses were invariably minute. The combined inoculation of these microorganisms resulted in the induction of intraabdominal abscesses larger than those formed by Bacteroides fragilis or Escherichia coli alone. However, the size difference between abscesses produced by Escherichia coli alone and by the combination of both organisms was not statistically significant. The animal model defined in this study differed from earlier models in that use of the complex sterile cecal contents can be avoided. This allows for a more precise evaluation of the contribution of each organism to the pathogenic process of intraabdominal abscess formation.
Abdomen↗
In vitro stimulation of Bacteroides fragilis growth by Escherichia coli.
The interaction between Bacteroides fragilis and Escherichia coli was investigated by following their growth kinetics in an in vitro mixed culture system. In Bacto-peptone or in a semisynthetic medium (SSM-M) Bacteroides fragilis could initiate growth only when a small number of viable Escherichia coli initially coexisted for a short period of time. Both Bacto-peptone and SSM-M previously spent by Escherichia coli also allowed Bacteroides fragilis growth to occur but the supplementation of heat killed Escherichia coli cells or viable cell homogenates to fresh media failed to stimulate Bacteroides fragilis growth. The in vitro stimulation of Bacteroides fragilis growth by Escherichia coli observed in this study may be best explained by the combination of (a) removal of oxygen and other toxic substances and (b) de novo production of Bacteroides fragilis growth stimulating factor(s) by coexistent Escherichia coli.
Abdomen↗
An experimental model for pyogenic liver abscess.
We have developed a reproducible small-animal model for pyogenic liver abscess, suitable for investigating diagnostic and therapeutic modalities. Male New Zealand white rabbits weighing 2-3 kg were anaesthetized and the liver exposed. Gentle pressure was applied with forceps to the right hepatic lobe. A suspension of 10(5) colony forming units (cfu) Escherichia coli plus Fusobacterium necrophorum (10(6) cfu) plus Bacteroides fragilis (10(6) cfu) was immediately injected into a mesenteric vein. Two weeks later a palpable mass (mean diameter 4 cm) had developed. Thick pus could be aspirated percutaneously. Necropsy revealed a single, but often multiloculated, abscess at the site of the previous trauma. Injection of E. coli alone did not produce any abscesses and B. fragilis alone only small abscesses, with low and variable frequency. Inoculation with F. necrophorum alone produced large abscesses, and a dose-response relationship was established. This is a simple and reliable small-animal model useful in studies of imaging techniques, antibiotic regimens and invasive treatments for pyogenic liver abscess.
Animals↗
Toxins from anaerobic bacteria: specificity and molecular mechanisms of action.
Major advances have been made in the past five years in the identification of cellular targets of toxins produced by anaerobic bacteria. These targets include the vesicular membrane docking and fusion apparatus, the actin cytoskeleton, the signal transduction machinery and the cell membrane. The recent discovery that large clostridial toxins (Clostridium difficile A and B toxins, C. sordellii lethal and hemorrhagic toxins, and alpha C. novyi toxin) are monoglucosyltransferases, together with the establishment of the perfringolysin crystal structure, has led to new insights in the field of toxins from anaerobic bacteria.
Bacterial Toxins↗
Comparison of roxithromycin with co-amoxiclav in patients with sinusitis.
In an open, randomized study of 60 patients with acute or recurrent sinusitis, the bacteriological and clinical efficacy of roxithromycin 150 mg bd were compared with those of po co-amoxiclav (625 mg) tds. Of 52 patients who underwent sinus puncture for isolation of causative organisms, 48 had pathogens sensitive to both antibiotics. Satisfactory clinical response was obtained in 93.1% (27/29) evaluable patients receiving roxithromycin and 88.8% (24/27) receiving co-amoxiclav. Tolerability was significantly better in the roxithromycin group, with 1/29 (3.4%) patients in this group experiencing gastrointestinal side-effects, compared with 7/27 (25.9%) patients in the co-amoxiclav group (P < 0.05). Although the study had limited power to detect differences, roxithromycin demonstrated clinical, bacteriological and overall efficacy similar to that of co-amoxiclav, but with better tolerability. Roxithromycin thus appears to be an effective and well-tolerated drug for the treatment of acute and recurrent sinusitis.
Adolescent↗
Bacterial killing in vitro by abscess-derived neutrophils.
In the absence of antimicrobial therapy, bacteria such as Bacteriodes fragilis, Escherichia coli and Proteus mirabilis may persist within an intra-abdominal abscess in the presence of large numbers of neutrophils which, under optimal conditions in vitro, can readily phagocytose and kill the same bacterial strains. Neutrophils taken from abscesses induced by gram-negative bacteria such as those above contain viable organisms. On incubation in vitro in the presence of serum, these neutrophils kill the bacteria phagocytosed in the abscess poorly, if at all, yet can readily kill organisms added in vitro. To determine possible mechanisms that might explain this, we examined the bactericidal activity in vitro of neutrophils from a range of abscesses induced by one or two species of bacteria plus an abscess-potentiating agent, bran. The organisms studied were B. fragilis, E. coli, P. mirabilis and Staphylococcus aureus. The killing in vitro of E. coli and P. mirabilis, engulfed within an abscess, was significantly less than that of the same organisms when they were added to the in-vitro assay. In contrast, the killing of S. aureus was similar, whether engulfed in vivo or in vitro. However, S. aureus was less susceptible to phagocytosis and killing in vitro than P. mirabilis or E. coli, and the killing of S. aureus during in-vitro incubation of neutrophils that had engulfed the organism with in the abscess was similar to that of the gram-negative bacteria engulfed within the abscess.(ABSTRACT TRUNCATED AT 250 WORDS)
Abscess↗
Gas-liquid chromatography of positive blood cultures for rapid presumptive diagnosis of anaerobic bacteremia.
Gas-liquid chromatographic analysis of volatile fatty acid patterns was performed when growth was initially detected in 87 positive blood cultures. Isovaleric acid, butyric acid, or both were found in 39 of 43 (90%) blood cultures that contained anaerobes but were absent in all 44 cultures that contained facultatively anaerobic or aerobic bacteria. The detection of isovaleric acid indicated the presence of Bacteroides fragilis, as this acid was found in 88% of unimicrobial and 75% of polymicrobial bacteremias due to B. fragilis. Butyric acid was detected most often in blood cultures which grew Fusobacterium spp. (three of three), Clostridium spp. (six of seven), or both (three of four).
Bacteroides Infections↗
Response of a 'susceptible' Escherichia coli to metronidazole therapy: an investigation using experimental subcutaneous abscesses.
Earlier experiments under anaerobic conditions in vitro had indicated that Gram-negative facultative anaerobes were susceptible to therapeutically attainable concentrations of metronidazole. This prompted us to study the response of one such strain to metronidazole therapy. Mice with 3-day-old subcutaneous abscesses induced by 'susceptible' Escherichia coli (accompanied by potentiating agent and obligately anaerobic Bacteroides fragilis) were given metronidazole by mouth (250 mg/kg/dose 12 hourly) either as a two- or a four-dose course. This therapy reduced the viable numbers of E. coli/abscess by a mere 0.3 log10 and 0.7 log10, respectively. Assays showed that concentrations of metronidazole in abscess-contents compared favourably with those in the earlier in vitro experiments. But measurement of redox potentials in abscesses indicated that the conditions in these (-191 mV vs. Ag/AgCl) were not nearly as reduced as those in experiments in vitro (-650 mV). This, and the known dependence of metronidazole on low redox potentials for expression of its antimicrobial ability, appears to be the explanation for the poor anticoliform effect in the subcutaneous abscess model. Full assessment of the clinical implications of these observations must await the availability of data regarding redox potentials in clinical situations.
Abscess↗
Tension pneumopericardium caused by positive pressure ventilation complicating anaerobic pneumonia.
A 22-year-old man was admitted with pneumonia. He was immediately intubated and positive pressure ventilation was initiated. Blood and sputum cultures showed Bacteroides fragilis and Corynebacterium sp., which were treated with metronidazole and clindamycin. Three weeks later his blood pressure suddenly dropped with an elevation of the central venous pressure. Chest X-ray revealed a pneumopericardium. A parasternal mediastinotomy with partial pericardiectomy was immediately performed. On opening the pericardium his blood pressure normalised. The patient gradually recovered and six weeks after admission he was extubated. Two weeks later he was discharged. A pneumopericardium without previous thorax trauma is very rare and early recognition is imperative because a tension pneumopericardium with cardiac tamponade may develop, as happened in this case. A tension pneumopericardium has to be treated with immediate pericardiocentesis followed by partial pericardiectomy to avoid recurrence.
Adult↗
[Experimental simulation of liver abscess in the rabbit].
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Animals↗
An experimental model of intraabdominal abscess in the rat.
Suitable small animal models of intraabdominal abscess are not available. We have developed a reliable model of intraabdominal abscess in the rat by fasting the animal overnight, devascularizing and ligating the cecum, and injecting 2.5 X 10(8) Escherichia coli and 2.5 X 10(9) Bacteroides fragilis into the ligated cecum. This model results in 39% coli acute mortalities within 48 hours from acute peritonitis, and abscess in 76% of survivals. Subsequent abscesses are 1.0--1.5 ml in volume and contain 4 X 10(8) E coli/ml of pus and 1.4 X 10(9) B fragilis/ml. This model allows chronic evaluation of sepsis in small animals and provides a convenient means to study the abscess microenvironment.
Abdomen↗
[Psoas abscess. The diagnostic and therapeutic considerations in 5 patients].
Five cases of psoas abscesses are discussed, four pyogenes and one tuberculous, the current etiology of this process, together with its pathogenesis and clinical manifestations are discussed. In all of them the guided punction through Computerized Axial Tomography (CAT) has been the way to diagnose and treat the process. Utility of this technique considering both aspects is discussed because it allows to determine the etiology and avoids the surgical drainage; even tough this therapy should be individualized in each case, probably is in primary staphylococci abscesses where this therapeutic option is best indicated.
Adult↗
Prostaglandin E2 modulation of p59fyn tyrosine kinase in T lymphocytes during sepsis.
Prostaglandin E2 (PGE2) has been implicated in the suppression of T cell IL-2 production and proliferation during burn and sepsis. The present study evaluated the potential intracellular mechanism of suppressed T cell responses by assessing the activation of p59fyn kinase in T cells from septic rats as well as the T cells incubated with PGE2. p59fyn is known to regulate T cell functions. Sepsis was induced in rats by implanting fecal pellets containing Escherichia coli (150 CFU) and Bacteroides fragilis (10(4) CFU) into the abdominal cavity. For the assessment of PGE2 role in sepsis, a group of septic rats were treated with indomethacin, which inhibits endogenous PGE2 synthesis. As assessed by immunoblotting or in vitro kinase assay, a more than 40% inhibition of p59fyn phosphorylation and kinase activity was observed in septic rat T cells compared with the T cells from sterile or control rats. A similar inhibition in p59fyn phosphorylation and kinase activity was observed in PGE2-treated T cells compared with the T cells incubated in the absence of PGE2. The septic-related suppression in p59fyn phosphorylation and kinase activity in T cells was prevented in rats treated with indomethacin. We observed that the inhibition in p59fyn activation in septic or PGE2-treated T cells was due primarily to a suppression in p59fyn phosphorylation and not due to alterations in p59fyn protein expression. These findings suggest that PGE2 released during sepsis could contribute to the sepsis-related suppression in T cell proliferation by attenuating p59fyn phosphorylation and its kinase activity.
Animals↗
Phages of enteric bacteria in fresh water with different levels of faecal pollution.
Levels of somatic and F-specific coliphages, and phages infecting Bacteroides fragilis were measured in 257 samples collected in different freshwater environments with different levels and characteristics of faecal pollution. In samples with recent pollution of domestic origin, the numbers of the three groups of phages were highly correlated, thus showing that their excretion is fairly constant. In this set of samples somatic coliphages, which were the most abundant, and F-specific coliphages outnumbered significantly Bact. fragilis phages. Normalized lines of the numbers of the three groups of phages in water samples and their sediments show that they settle similarly. The correlation between the values of the three groups of phages was not observed in waters with intermediate levels of pollution. An increase in the relative numbers of coliphages with respect to numbers of phages infecting Bact. fragilis was observed. In waters with persistent faecal pollution a dramatic change was recorded in the relative numbers of the different groups of phages. Phages infecting Bact. fragilis suffered the lowest reduction in numbers.
Bacteroides fragilis↗
Activity of imipenem against Pseudomonas and Bacteroides species.
The activity of imipenem against Pseudomonas aeruginosa and Bacteroides fragilis in vitro was studied. MICs of imipenem for P. aeruginosa are approximately 2 micrograms/m. Unlike most other beta-lactam antibiotics, imipenem does not show cross-resistance in the presence of intrinsic resistance. Imipenem is a strong inducer of Id beta-lactamase but is stable to hydrolysis by this enzyme. B. fragilis is more susceptible to imipenem than to other beta-lactam antibiotics. The activity of imipenem against B. fragilis is similar to that of metronidazole. The cephalosporinases of B. fragilis do not inactivate imipenem.
Bacteroides Infections↗
Intravenous metronidazole therapy for Bacteroides fragilis meningitis.
A 69-year-old man developed meningitis due to Bacteroides fragilis and Streptococcus MG-intermedius, which progressed during chloramphenicol and nafcillin therapy to the extent that he seemed near death, with frank pus covering the spinal cord at surgery. Treatment with intravenous metronidazole and penicillin G was curative. After multiple trauma, a 20-year-old man developed meningitis due to Escherichia coli and B fragilis. He failed to respond to chloramphenicol alone, but responded to combined treatment with chloramphenicol and metronidazole. The right frontal sinus and epidural space abscesses were drained and a right frontal lobe abscess was excised. Metronidazole may be a uniquely effective agent for treatment of meningitis due to susceptible strains of Bacteroides fragilis.
Adult↗