Search PubMed⌕ Search

Biomedical subjects

G L Simon

Publications and source records attributed to G L Simon.

69 records · Page 4Linked to original sources
PubMed1983

Synovial fluid inhibits killing of Staphylococcus aureus by neutrophils.

Serum in the extracellular environment promotes neutrophil bactericidal activity apart from its opsonizing properties. We examined the effect of non-inflammatory osteoarthritic synovial fluid on serum-mediated neutrophil killing of Staphylococcus aureus. This was done to evaluate the effect of synovial fluid on neutrophil bactericidal activity independent of opsonin concentration. With an initial inoculum of 5 X 10(6) CFU/ml, 1.47 +/- 0.14% bacteria survived after 120 min of incubation with 10% serum and neutrophils. In contrast, 4.07 +/- 0.33% bacteria survived after incubation in serum plus synovial fluid (P less than 0.001). This inhibitory effect was directly related to the concentration of synovial fluid in the incubation mixture. Increasing the concentration of synovial fluid resulted in an increased percent survival. Studies utilizing preopsonized bacteria and radiolabeled organisms demonstrated that synovial fluid did not interfere with opsonization or phagocytosis. Intracellular bactericidal activity was assayed separately from phagocytosis by utilizing a brief ingestion period followed by the removal of extracellular bacteria by either differential centrifugation or lysostaphin treatment. The reincubation of cells and associated bacteria with serum or serum plus synovial fluid revealed that synovial fluid significantly inhibited the promoting effect of serum on neutrophil bactericidal activity. After 60 min of incubation with 10% serum, 13.0 +/- 1.2% bacteria survived, whereas 21.5 +/- 2.3% survived after incubation in serum plus synovial fluid (P less than 0.005). Superoxide production was not affected by the presence of synovial fluid. These findings suggest that the inhibitory effect of synovial fluid is due to an interaction between synovial fluid and the serum factors that promote intracellular killing.

Blood Bactericidal Activity↗
PubMed1983

A comparative study of surgical skin preparation methods.

Analysis of a randomized study of preoperative skin preparation techniques in thoracic and general surgical patients revealed that the use of a one minute alcohol cleansing and application of an antimicrobial film provides equivalent bactericidal activity to a five minute iodophor scrub and paint. Initial bacterial kill is greater with a one minute alcohol cleansing than a five minute iodophor scrub. There were fewer patients with high bacterial counts at the time of closure in the groups treated with the antimicrobial film than in the traditional iodophor scrub group. Saving in preoperative operating room time can be achieved using a one minute alcohol cleansing plus application of an antimicrobial film with equal antibacterial efficacy to that of conventional methods.

Bacteria↗
PubMed1982

Alterations in opsonophagocytic killing by neutrophils of Bacteroides fragilis associated with animal and laboratory passage: effect of capsular polysaccharide.

Electron microscopic studies of laboratory-passaged and animal-passaged isolates of Bacteroides fragilis showed significantly more capsular material around the latter. This observation correlated with increased survival of animal-passaged bacteria in rabbit intraperitoneal chambers and increased resistance to phagocytosis and opsonophagocytic killing by neutrophils. With an initial inoculum of 2.5 x 10(6) colony-forming units/ml, the number of bacteria surviving after incubation for 2 hr with neutrophils and pooled normal human serum was significantly (P less than 0.01) greater for animal-passaged than for laboratory-passaged bacteria. Neutrophil uptake of 14C-labeled animal-passaged and laboratory-passaged bacteria after incubation for 20 min was 45% and 63%, respectively (P less than 0.05). No significant difference in survival was found between animal-passaged and laboratory-passaged isolates of Bacteroides thetaiotaomicron. These findings suggest that on mechanism whereby the capsule of B. fragilis contributes to virulence is by inhibiting opsonophagocytic killing.

Animals↗
PubMed1982

Efficacy of ceftriaxone in serious bacterial infections.

Ceftriaxone is a new semisynthetic cephalosporin with broad-spectrum in vitro activity and an unusually long serum half-life. The clinical efficacy of ceftriaxone was evaluated in 35 infections in 34 patients; 12 of these patients had skin and soft tissue infections, 10 had infections of the urinary tract, 8 had pneumonia, 2 had biliary tract infections, 1 had sinusitis, 1 had diverticulitis, and 1 had a retroperitoneal abscess. Of the 35 infections, 9 were bacteremic. The bacteria isolated included Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus faecalis, other streptococcal species, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Serratia marcescens, Enterobacter cloacae, Haemophilus influenzae, Pseudomonas aeruginosa, Bacteroides fragilis, other Bacteroides species, and anaerobic cocci. Improvement or cure occurred in 32 episodes, for a response rate of 91%. There were three treatment failures in patients with soft tissue infections. No serious drug toxicities were observed. At a dosage regimen of 1 g every 12 h the peak and trough serum antibiotic concentrations were well above the minimal inhibitory concentrations of most pathogens. Our findings suggest that ceftriaxone is a safe and effective antibiotic for therapy of serious bacterial infections.

Adult↗
PubMed1981

Toxic shock syndrome in a male postoperative patient.

A patient is described who postoperatively developed a clinical syndrome characteristic of toxic shock syndrome following amputation of a previously injured finger. A small stitch abscess was identified which grew Staphylococcus aureus. The patient became ill within 12 hours of surgery, suggesting that a small inoculum of a toxic shock-producing strain of S. aureus can produce the clinical syndrome.

Adult↗
PubMed1980

Clinical trial of piperacillin with acquisition of resistance by Pseudomonas and clinical relapse.

A total of 20 serious infections were treated with piperacillin. These infections included bacteremias (5), pneumonias (5), urinary tract infections (5), soft tissue infections (3), septic arthritis (1), and osteomyelitis (1). The most common bacterial pathogen was Pseudomonas aeruginosa, accounting for eight infections. The clinical and bacteriological response rates were 75 and 70%, respectively. Four of the five patients who failed to respond to piperacillin therapy were infected with Pseudomonas. In two patients with Pseudomonas infections clinical relapse was accompanied by the development of piperacillin-resistant P. aeruginosa. The findings suggest that the use of piperacillin as a single agent for the treatment of serious gram-negative infections may be ill-advised, especially if P. aeruginosa is the offending pathogen.

Adolescent↗
PubMedDate not supplied

Intracranial tuberculosis due to Mycobacterium bovis.

A case of intracranial tuberculosis due to Mycobacterium bovis is presented. Computed tomography (CT) identified multiple enhancing lesions which by biopsy proved to be intracranial tuberculomas. The CT appearance, epidemiology and bacteriology as well as pharmacotherapy of this uncommon entity are discussed.

Adult↗
PubMedDate not supplied

Paranasal sinus mucormycosis in an immunologically competent host.

A case of paranasal sinus mucormycosis in an immunocompetent patient is reported. After an extensive evaluation, no evidence of either diabetes mellitus or underlying immunologic abnormality was found. The combination of excisional surgery and amphotericin B therapy resulted in an excellent response. High-resolution axial and coronal computed tomography was useful in both planning treatment and monitoring the response to therapy.

Adult↗
PubMedDate not supplied

Listeria monocytogenes infections in patients with AIDS: report of five cases and review.

Five patients with AIDS and Listeria monocytogenes infection (three cases of bacteremia and two of meningitis) are reviewed. Four patients had prior or concurrent gastrointestinal illness. Two patients received corticosteroids. A 7- to 21-day course of ampicillin was administered with or without a 7- to 14-day course of gentamicin. This regimen was effective, with no evidence of relapse 7-8 months after therapy was discontinued. The relative infrequency of infection with L. monocytogenes in AIDS patients is unexpected. Tumor necrosis factor (TNF) appears to be essential in the inhibition of Listeria in vivo. Elevated levels of TNF in AIDS patients may be protective against listeriosis and thus help explain the low prevalence of listerial infection in this population. Nonetheless, although L. monocytogenes is an uncommon cause of illness in patients infected with the human immunodeficiency virus, it cannot be dismissed as a cause of undefined meningitis or sepsis.

Acquired Immunodeficiency Syndrome↗