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Biomedical subjects

C E Edmiston

Publications and source records attributed to C E Edmiston.

53 records · Page 3Linked to original sources
PubMed1990

Adherence of mucin and non-mucin-producing staphylococci to preclotted and albumin-coated velour knitted vascular grafts.

The mechanisms involved in bacterial adherence to vascular grafts are important in understanding prosthetic infections. Albumin-coated Dacron (ACD) is a new development in vascular graft fabrication. However, albumin acts as a receptor for certain gram-positive bacterial adhesions. Five pathogenic, coagulase-negative Staphylococcus epidermidis strains were used to measure the differential microbial adherence to ACD versus untreated velour-knitted Dacron (VKD) vascular prostheses. Specimens of VKD, preclotted VKD, and ACD were inoculated with each of the five strains (10(7) colony-forming units/ml) for 2, 4, 8, 12, and 24 hours. After incubation, graft specimens were washed to remove nonadherent organisms and oscillated ultrasonically to remove adherent organisms. The sonication effluent was plated to trypticase soy agar to quantitate the adherent organisms. Adherence was significantly greater (p less than 0.01) to VKD compared with preclotted VKD and ACD at 2, 4, 8, and 24 hours. Four of the five study strains demonstrated significantly greater adherence to VKD than to either ACD or preclotted VKD. Adherence of S. epidermidis increased with exposure time. Albumin bonded to velour-knitted Dacron does not increase coagulase-negative staphylococcal adherence compared with the noncoated vascular prostheses. Binding albumin to vascular prostheses does not increase the risk of staphylococcal colonization.

Bacterial Adhesion↗
PubMed1989

The efficacy of oral antimicrobials in reducing aerobic and anaerobic colonic mucosal flora.

We investigated the impact of intestinal antisepsis on the colonic mucosa-associated flora. Four groups of dogs were studied: group A received no bowel preparation, group B received a three-day clear-liquid diet, group C underwent mechanical cleansing of the bowel, and group D had mechanical cleansing followed by oral neomycin and erythromycin. Mucosal biopsy specimens were obtained for bacteriologic and scanning electron microscopic (SEM) studies. No significant difference in recovery of mucosal bacteria was observed between groups A and B. A significant decrease in recovery of aerobes was observed in group C, and a significant decrease in both aerobes and anaerobes was observed in group D compared with group A; Enterobacteriaceae and Bacteroides were either eliminated or greatly reduced. The SEM analysis of group D revealed a marked decrease in mucosa-associated microflora compared with groups B and C. Oral neomycin-erythromycin produced a significant quantitative reduction in the colonic mucosa-associated bacterial population, including the potentially pathogenic Escherichia coli and Bacteroides fragilis group isolates. These mucosa-associated bacteria are a likely source of contamination of the abdominal cavity and wound at the time of colon surgery.

Administration, Oral↗
PubMed1989

Coagulase-negative staphylococcal infections in vascular surgery: epidemiology and pathogenesis.

Staphylococcal infection of a vascular prosthesis is a relatively uncommon complication of peripheral vascular surgery; however, these infections and their sequelae can be catastrophic. The majority of prosthetic graft infections are caused by mucin-producing strains of Staphylococcus epidermidis, which express varying degrees of adherence to the synthetic substrates. Studies have demonstrated that the components and construction characteristics of the graft, implantation site, administration of antimicrobial agents, and endogenous microbial flora are all identifiable risk factors in vascular graft infections. Mucin production, a known virulence factor, has recently been shown to occur in endogenous coagulase-negative staphylococci (CNS) at the time of hospital admission. While mucin production plays an important role in the persistence of graft infections, there is no evidence that suggests a relationship between mucin and antimicrobial resistance. Identifying characteristics of (CNS) graft infections may include a draining wound sinus, poor graft incorporation, a perigraft exudate or a pseudoaneurysm at the anastomotic site. The occult nature of these infections, in which the patient is often asymptomatic, makes diagnosis and treatment difficult. The graft or graft exudate may be negative when routine culture methods are employed. The recognition of CNS graft infections requires a high index of suspicion and the treatment of these infections requires understanding of the pathogenic process, individualized surgical management, and the judicious use of antimicrobial agents.

Blood Vessel Prosthesis↗
PubMed1988

A prospective study of the microflora of nonpuerperal breast abscess.

The majority of reports concerning nonpuerperal breast abscess (NPBA) identify aerobic and facultative bacterial isolates as the predominant flora in this disease. In the present study, fine-needle aspiration was performed in 29 women with NPBA; 12 (41%) of the patients had a history of chronic NPBA. The mean age of patients was 39.2 years. The aspirated material was cultured both anaerobically and aerobically. A total of 108 bacterial strains were recovered from 32 specimens; two specimens yielded no bacterial growth. A mean of 3.6 different bacteria were recovered from each culture-positive specimen. Anaerobic recovery outweighed aerobic-facultative recovery by a factor of 2:1. Significantly, 37 strains (five aerobes and 32 anaerobes) were harvested only from enriched broth subcultured for four to 14 days after initial culture processing. Coagulase-negative staphylococci (60% of total aerobes) and peptostreptococci (47% of total anaerobes) were the predominant bacterial isolates. These findings indicate that NPBA is due to a mixed flora with a major anaerobic component. Furthermore, the results suggest that routine cultures often overlook the involvement of anaerobes in these infections.

Abscess↗
PubMed1988

Comparative in vitro beta-lactam activity against aerobic and anaerobic surgical isolates.

The comparative in vitro activity of cefoxitin, piperacillin, cefotetan, and ceftizoxime was compared against 843 surgical microbial isolates. All compounds exhibited excellent activity against the streptococcal isolates. Antimicrobial activity was poor for Staphylococcus aureus and S. epidermidis. Cefotetan activity against the Enterobacteriaceae was comparable to ceftizoxime (greater than 95% susceptible). Resistance rates of 0, 1, 5, and 2% were observed with cefoxitin, piperacillin, cefotetan, and ceftizoxime against the anaerobic cocci and anaerobic gram-positive non-spore-forming rods. Ninety-six and ninety-nine percent of the clostridial strains were susceptible to cefotetan and piperacillin, respectively. Piperacillin, cefotetan, and ceftizoxime exhibited similar activity against Bacteroides fragilis (resistance less than 10%). Cefotetan and cefoxitin exhibited poor activity against Bacteroides distasonis, B. ovatus, and B. thetaiotaomicron. Antimicrobial activities were comparable for the four drugs against other Bacteroides and Fusobacterium species. The results demonstrate that all four compounds exhibited broad antimicrobial activity against facultative and obligate anaerobic surgical isolates from intraabdominal and soft tissue infections.

Abdomen↗
PubMed1986

Aztreonam concentration in abdominal tissues and bile.

Abdominal tissue, serum, and bile samples were obtained from 37 patients given a single, 2-g intravenous infusion of aztreonam immediately prior to an elective abdominal operation. Samples were obtained at 0 to 6 h after dosing. Mean concentrations in tissues and fluids and specimen/serum rations are reported. Levels in tissue and bile exceeded the reported MICs for 90% of most members of the family Enterobacteriaceae for up to 6 h.

Abdomen↗
PubMed1985

Evaluation of carbamate toxicity: acute toxicity in a culture of Paramecium multimicronucleatum upon exposure to aldicarb, carbaryl, and mexacarbate as measured by Warburg respirometry and acute plate assay.

The present study was undertaken to explore the acute toxicity of three carbamate pesticides, aldicarb, carbaryl, and mexacarbate, on a population of Paramecium multimicronucleatum. The toxicity was evaluated by the Warburg respirometer and the static acute plate assay. Aldicarb, carbaryl, and mexacarbate were shown to significantly inhibit cumulative oxygen uptake at 24 hr in the paramecium culture at 160, 120, and 100 ppm, respectively. Aldicarb, carbaryl, and mexacarbate concentrations of 60, 20, and 10 ppm demonstrated no inhibition of cumulative oxygen uptake when compared to a paramecium control at 24 hr. Pesticide concentrations intermediate to the high and low concentrations demonstrated varying degrees of inhibition. Static plate assay data for aldicarb demonstrated LC50 values of 93, 104, 122, and 145 ppm at 24, 17, 13, and 9 hr, while carbaryl demonstrated LC50 values of 28, 34, 46, 65, and 105 ppm at 24, 17, 13, 9, and 7 hr, respectively. Mexacarbate LC50 values were 19, 25, 35, 57, and 83 ppm at 24, 17, 13, 9, and 7 hr. Oxygen uptake values compared favorably with the static assay data. Scanning electron micrographs demonstrated several morphologic changes in paramecium with increased pesticide concentration and exposure time including ciliary abnormalities and disruption of surface structure.

Aldicarb↗
PubMed1982

Anaerobic bacterial populations on normal and diseased human biopsy tissue obtained at colonoscopy.

Human epithelium was cultured to characterize differences in microbial populations between regions of normal colon and between polyps, inflammatory bowel disease, and cancer and their respective adjacent normal mucosa. Twenty-one patients (12 polyps, 5 inflammatory bowel disease, 4 cancer) underwent colonoscopy with anaerobic culture of mucosal biopsies from normal and diseased ascending, transverse, descending, and sigmoid colon. No differences for total number of organisms and recovery of species between ascending colon and other normal regions were seen except for sigmoid colon. Significant differences between polyps and adjacent normal tissue were seen for total number of organisms and recovery of genera and species. No significant differences in total number of organisms and recovery of genera were seen between cancer and inflammatory bowel disease and their respective adjacent normal tissue. The recovery of genera from polyps and normal tissue was Bacteroides greater than Fusobacterium greater than Clostridium greater than Eubacterium greater than Peptostreptococcus. These data suggest that (i) the total number of anaerobic organisms and species remained relatively constant, except for lower numbers in normal distal colon which were probably a result of the preparation for colonoscopy; (ii) polyp formation favored increased microbial colonization; and (iii) the increased number of organisms generally reflected those genera and species seen on adjacent normal mucosa.

Anaerobiosis↗
PubMed1979

Microbial colonization and hepatic abnormalities in jejunoileal bypass with resection, ileal mucous fistula, and ileocolostomy.

A role for bacterial colonization of the intestines in the pathogenesis of hepatic abnormalities after jejunoileal bypass was sought. Dogs were divided into groups according to the disposition of the bypassed segment; resection (group I), exteriorization as an ileal mucous fistula (group II), and drainage via an ileocolonic anastomosis (group III). Weight loss, abnormalities in liver function, and hepatic steatosis were significantly greater in groups II and III than in group I. Concomitantly, there was a significant increase in the total number of bacterial colony-forming units in groups II and III. Moreover, a greater number of specific anaerobic genera was isolated in group III than in group II. It is concluded that: (1) retention of the bypassed intestinal segment is associated with greater changes in liver function and structure than when the segment is resected; (2) the changes in the liver correlated with bacterial proliferation in the bypassed intestinal segment; and (3) despite a greater number of anaerobic genera in the ileocolostomy than in the mucous fistula, both procedures were associated with hepatic abnormalities.

Animals↗
PubMed1979

Evaluation of gentamicin and penicillin as a synergistic combination in experimental murine listeriosis.

The administration of a combination of penicillin and gentamicin to mice given an intraperitoneal challenge of a highly pathogenic strain of Listeria monocytogenes resulted in increased survival as compared with groups receiving penicillin alone or gentamicin alone or a control group that received no antibiotic. The median survival of animals that eventually died was no longer than in groups receiving single antibiotics and suggests that additional studies should be carried out to further investigate the possibility of synergism in animal models.

Animals↗
PubMed1976

Comparative in vitro studies of cinoxacin, nalidixic acid, and oxolinic acid.

Cinoxacin and nalidixic acid were found to be similar in in vitro activity against 138 Shigella isolates and somewhat less active than oxolinic acid on a weight basis. Cross-resistance developed when 10 shigellae were transferred on increasing amounts of the respective agent contained in Mueller-Hinton agar. Plate dilution studies of the effect of changes in agar pH on the minimum inhibitory concentration revealed that the antibacterial activity increased with decreasing pH. Protein binding investigations revealed a high degree of binding, with nalidixic acid > oxolinic acid > cinoxacin.

Culture Media↗
PubMedDate not supplied

Fecal peritonitis: microbial adherence to serosal mesothelium and resistance to peritoneal lavage.

Fecal contamination of the peritoneal cavity is a serious and potentially life-threatening event. While numerous models have been developed to study the pathogenesis of intraabdominal infection, to date, most investigations have failed to focus on the adherence of the contaminants to the serosal mesothelium. In the present investigation, the cecal ligation and puncture technique (CLP) was performed in Sprague-Dawley rats to study the following: (a) the kinetics of microbial adherence to the serosal mesothelium, (b) the stability of the aerobic and anaerobic intraperitoneal/mesothelial populations, following extended saline lavage, and (c) the impact of antimicrobial lavage on the stability of the mesothelial microbial populations. The Enterobacteriaceae rapidly colonized the serosal mesothelium and were the predominant flora up to 4 hours post-CLP. After 8 hours, the Bacteroides fragilis group represented the predominant peritoneal wash and mesothelial-associated microorganisms. Extended saline lavage failed to significantly reduce the mesothelial microbial populations. While antimicrobial lavage produced an immediate decrease in mesothelial microbial recovery, the results were transitory and the microbial populations achieved or exceeded prelavage levels at 24 hours postlavage. Microbial colonization of the peritoneal mesothelial surface is a rapid and stable phenomena following penetrating injury to the distal bowel. The results further suggest that the mesothelial populations are resistant to intraperitoneal lavage.

Animals↗
PubMedDate not supplied

Streptococcus milleri group (Streptococcus anginosus): recovery from intra-abdominal and soft tissue sites.

One hundred thirty-three Streptococcus milleri group (S. anginosus) isolates were recovered from 487 surgical patients. The streptococci were recovered from 33 percent of intra-abdominal infection cultures (84/257). 22 percent of samples from penetrating visceral trauma (19/86), 52 percent of perirectal abscess specimens (13/25), 13 percent of nonpuerperal breast abscess cultures (8/60), and 15 percent of diabetic foot lesions (9/59). Ninety-eight percent of the S. milleri (131/133) were recovered as companion flora in polymicrobial cultures. The organisms were highly susceptible to the beta-lactam antibiotics. The precise pathogenic role of the S. milleri group (S. anginosus) is unknown. However, intrinsic virulence may be expressed in patients with severe infection or other predisposing factors.

Abdomen↗
PubMedDate not supplied

Post-antibiotic effect in Bacteroides fragilis group.

Post-antibiotic effect (PAE) is the transient suppression of bacterial growth after brief antimicrobial exposure. While numerous reports have described PAE with aerobic and facultative microorganisms, virtually no studies have been conducted with anaerobic isolates. Intraabdominal isolates of the Bacteroides fragilis group were exposed for one hour to antibiotic (cefoxitin, cefotetan, and imipenem) concentrations two to four times the minimal inhibitory concentration (MIC). Post-antibiotic effect was described as the difference between the time required for microbial growth in the test versus the control to increase one Log10 above the quantitation observed immediately after drug removal. Bacteroides fragilis, B. ovatus, B. thetaiotaomicron and B. vulgatus exhibit PAEs for all test compounds. The time intervals for the PAEs were strain variable and ranged from six to 50 hours. No PAE was demonstrated with B. distasonis strains by the broth dilution technique. The results suggest that brief high dose exposure of some members of the B. fragilis group to anaerobe active beta-lactams produces a prolonged suppression in growth. In theory, a prolonged PAE could influence the dosage regimentation of selective antibiotics.

Bacteroides fragilis↗
PubMedDate not supplied

Pharmacoeconomic analysis of ampicillin-sulbactam versus cefoxitin in the treatment of intraabdominal infections.

We conducted a retrospective pharmacoeconomic analysis of a prospective, multicenter, double-blind, randomized, controlled trial comparing the beta-lactamase inhibitor combination ampicillin-sulbactam (96 patients) and the cephalosporin cefoxitin (101) in the treatment of intraabdominal infections. An institutional perspective was adopted for the analysis. The primary outcomes of interest were cure and failure rates, development of new infection, and antibiotic-related adverse events. Epidemiologic data pertaining to outcomes was retrieved primarily from the trial, although results of other published studies were taken into consideration through extensive sensitivity analyses. Data pertaining to potential resource use and economic impact were retrieved mainly from the University Health Consortium and hospital-specific sources. When considering only costs associated with drug acquisition through cost-minimization analysis, a potential savings of $37.24/patient may be realized with ampicillin-sulbactam relative to cefoxitin based on an average 7-day regimen. Outcome data collected for the entire hospitalization during the trial revealed an approximately 9% greater frequency of failure with cefoxitin relative to ampicillin-sulbactam. When considering all outcomes of interest in the initial base-case analysis, a potential cost savings of approximately $890/patient may be realized with ampicillin-sulbactam relative to cefoxitin. In assessing the impact of the significant variability in probability and cost estimates, Monte Carlo analysis revealed a savings of $425/patient for ampicillin-sulbactam over cefoxitin (95% CI -$618 to $1516 [corrected]). Given the model assumptions, our analysis suggests a 78% certainty level that savings will be experienced when ampicillin-sulbactam is chosen over cefoxitin.

Abdominal Abscess↗