Search PubMed⌕ Search

Biomedical subjects

D E Low

Publications and source records attributed to D E Low.

At least 163 records · Page 9Linked to original sources
PubMed1992

Prevalence of bloodborne infective agents among people admitted to a Canadian hospital.

OBJECTIVE: To determine the prevalence rates of hepatitis B surface antigen (HBsAg) and antibodies to the human immunodeficiency virus (anti-HIV) and the hepatitis C virus (anti-HCV) among people admitted to an urban Canadian hospital. DESIGN: Anonymous unlinked serosurvey. SETTING: A 420-bed teaching hospital in Toronto. PARTICIPANTS: All 3000 patients admitted to the hospital on weekdays from January to June 1990. An attempt was made to exclude those who were readmitted during the study period. INTERVENTIONS: Serum samples from all the patients were tested for HBsAg and anti-HIV, and 1306 samples were also tested for anti-HCV by means of enzyme immunosorbent assays; reactions were confirmed by means of specific antibody neutralization or immunoblot assay. MAIN RESULTS: The prevalence rates of HBsAg, anti-HIV and anti-HCV were 2.1% (95% confidence interval [CI] 1.6% to 2.6%), 0.6% (95% CI 0.3% to 0.9%) and 0.5% (95% CI 0.1% to 0.9%) respectively. CONCLUSIONS: This is the first report defining rates of infection with these bloodborne agents among patients admitted to a Canadian hospital. The observed rates likely reflect the patient population served by our hospital and do not necessarily apply to other Canadian centres. The results support the use of universal precautions in health care settings.

Adolescent↗
PubMed1992

Comparative in vitro activity of cefdinir (CI-983; FK-482) against staphylococci, gram-negative bacilli and respiratory tract pathogens.

The in vitro activity of cefdinir (CI-983; FK-482), a new oral cephalosporin, was compared with that of other antimicrobial agents against clinical isolates of staphylococci, gram-negative bacilli and common respiratory tract pathogens. Cefdinir (MIC90 less than or equal to 2.0 micrograms/ml) was more active than cefixime (MIC90 greater than 64 micrograms/ml) and equally as active as cefuroxime (MIC90 2.0 micrograms/ml) against oxacillin-susceptible staphylococci. Cefdinir was active against Haemophilus influenzae, including beta-lactamase producers (MIC90 0.5 microgram/ml), Moraxella catarrhalis (MIC90 less than or equal to 0.12 microgram/ml), Streptococcus pneumoniae (MIC90 less than or equal to 0.06 microgram/ml) and Streptococcus pyogenes (MIC90 less than or equal to 0.06 microgram/ml). The activity of cefdinir against gram-negative bacilli was variable; organisms with chromosomal cephalosporinases were often resistant.

Bacteria↗
PubMed1992

Pulmonary "twinning" procedure: use of lungs from one donor for single-lung transplantation in two recipients.

Since the introduction of lung transplantation as an option for patients with end-stage respiratory disease in the early 1980s, there have been substantial advances made in the technical aspects of transplantation as well as the early clinical results. With an ever-increasing number of patients being designated suitable candidates for transplantation, the volume of transplants in the foreseeable future will be limited more on the basis of donor lung supply than any other single factor. Pulmonary "twinning" provides an important step in ensuring that all suitable and available donor lungs are utilized whenever feasible. This report reviews the results of 20 single-lung transplantations carried out in five separate transplantation centers using organs retrieved from ten donors. The overall mortality rate in this group of patients was 5%, which compares very favorably with historical controls. No serious problem was noted with respect to increased perioperative morbidity or increased ischemic times in this group of patients. We suggest that this process should be considered and, wherever possible, adopted by all major lung transplant centers.

Adult↗
PubMed1992

Survey of Bacteroides fragilis group susceptibility patterns in Canada.

The in vitro activities of penicillin, clindamycin, chloramphenicol, metronidazole, piperacillin, piperacillin-tazobactam, ticarcillin, ticarcillin-clavulanate, ampicillin-sulbactam, cefoxitin, ceftizoxime, cefotetan, moxalactam, and imipenem against 348 Bacteroides fragilis group isolates collected from six Canadian cities during 1990 were determined by the National Committee for Clinical Laboratory Standards (NCCLS) agar dilution technique. All isolates were susceptible to chloramphenicol, metronidazole, piperacillin-tazobactam, and imipenem. For the other antibiotics tested, the following resistance rates were observed: penicillin, 97%; clindamycin, 9%; piperacillin, 19%; ticarcillin, 31%; ticarcillin-clavulanate, 0.28%; ampicillin-sulbactam, 0.85%; cefoxitin, 26%; ceftizoxime, 15%; cefotetan, 53%; and moxalactam, 17%. Susceptibility profiles to beta-lactam antibiotics varied among the different species tested: B. fragilis and Bacteroides vulgatus demonstrated lower resistance rates than Bacteroides distasonis and indole-positive Bacteroides thetaiotaomicron and Bacteroides ovatus. Ceftizoxime results should be interpreted cautiously, because the MICs obtained with the recommended NCCLS control strain were lower than expected.

Anti-Bacterial Agents↗
PubMed1992

Susceptibility testing of clinical isolates of Enterococcus faecium and Enterococcus faecalis.

We collected 103 clinical Enterococcus faecium isolates from across Canada, performed standard broth microdilution susceptibility testing, and compared these results with results from the MicroScan Pos MIC Type 6 panel (Baxter Health Care Corp., West Sacramento, Calif.) and the AMS-Vitek Gram-Positive Susceptibility card (Vitek Inc., St. Louis, Mo.). High-level aminoglycoside resistance to gentamicin and streptomycin was detected by a single-concentration agar method with 1,000 micrograms of each aminoglycoside per ml. In addition, we tested the effect of the lower calcium content in broth media as recommended in National Committee for Clinical Laboratory Standards (NCCLS) guideline M7-A2 on the activity of the highly calcium-dependent agent daptomycin. Of the 103 E. faecium isolates, there were 4 and 30 isolates with high-level gentamicin resistance (HLGR) and high-level streptomycin resistance (HLSR), respectively. An additional 39 (37 with HLGR and 36 with HLSR) E. faecium isolates were tested by both the MicroScan and the AMS-Vitek systems. The AMS-Vitek card demonstrated sensitivities of 95 and 82% for detecting HLGR strains and HLSR strains, respectively. The MicroScan panel demonstrated improved sensitivities for detecting HLGR (42 to 97%) and HLSR (64 to 84%) when readings were performed manually instead of being generated automatically. Ampicillin resistance (MIC, greater than or equal to 16 micrograms/ml) was detected in 23 of the 103 E. faecium isolates. Only 14 and 20 of these were detected by the MicroScan panels and AMS-Vitek cards, respectively. beta-Lactamase activity was not detected in any isolates. The lower calcium content in broth media recommended by NCCLS guideline M7-A2 markedly reduced the in vitro activity of daptomycin against Enterococcus spp.

Calcium↗
PubMed1992

Streptococcal erythrogenic toxin genes: detection by polymerase chain reaction and association with disease in strains isolated in Canada from 1940 to 1991.

The presence of genes encoding pyrogenic exotoxins type A (speA), B (speB), and C (speC) and streptolysin O (slo) was determined by the polymerase chain reaction (PCR) to target specific sequences in 152 strains of group A streptococci. These included reference strains, representative M and T type strains, and strains associated with scarlet fever and pharyngitis collected between 1940 to 1991 and included strains from patients with severe invasive streptococcal infections. PCR amplicons were detected by agarose gel electrophoresis, and specificity was established by restriction fragment analysis. The frequency of occurrence for each target gene among all strains tested was 33.6% for speA, 99.3% for speB, 28.9% for speC, and 100% for slo. Strains of non-group A streptococci, recognized toxigenic bacterial pathogens, and pneumolysin-producing Streptococcus pneumoniae strains were negative for all targeted gene sequences. Detection limits in the PCR were found to be 100 pg of total nucleic acids for the speB and speC genes and 1 ng for the speA and slo genes. Isolates associated with scarlet fever, pharyngitis, and severe invasive infections showed statistically significant differences in the presence of speA, with scarlet fever strains having the highest association (81.3%), severe infections the next highest association (42.9%), and pharyngitis the lowest association (18.4%). Although no significant differences were observed in speC frequencies in isolated associated with the three disease categories, a genotype of speB slo was significantly higher in isolates associated with pharyngitis (54.1%) than in strains associated with scarlet fever (18.8%) or severe invasive disease (23.8%). Streptolysin O targets were present in all the isolates tested, and only a single strain (T-11-M-11) was devoid of targeted speB sequences, thereby demonstrating that neither speB nor slo is associated with any particular clinical presentation.

Bacterial Proteins↗
PubMed1992

Detection of vancomycin resistance in Enterococcus species.

Enterococcus faecalis and Enterococcus faecium isolates that are resistant to vancomycin have recently been identified in North America and Europe. Of 155 clinical isolates of enterococci (113 E. faecium and 42 E. faecalis), we found that 98 were resistant, 52 were moderately susceptible, and 5 had intermediate susceptibilities to vancomycin by using broth microdilution susceptibility testing according to the National Committee for Clinical Laboratory Standards (NCCLS) (Approved Standard M7-A2). Using NCCLS disk diffusion methodology (Approved Standard M2-A4), we evaluated the NCCLS supplemental M100-S3 revisions for zone diameter interpretive standards and incubation conditions and found 5.8% minor errors. A total of 234 isolates, which included an additional 79 E. faecium isolates that were moderately susceptible to vancomycin, were used to evaluate the Vitek GPS-TA card (bioMerieux, Inc., Hazelwood, Mo.) and the Pos MIC type 6 panel (MicroScan; Baxter Health Care Corp., West Sacramento, Calif.) for the detection of vancomycin resistance. The Vitek card was 100% specific and 72% sensitive, whereas the MicroScan panel with the Walk/Away system was 98% specific, with a sensitivity of 93% which increased to 99% when readings were performed manually. An agar screen plate method was evaluated with vancomycin concentrations of 6, 8, 10, or 12 micrograms/ml; plates were inoculated so as to obtain a final concentration of 10(5) CFU per spot. This method was found to be 100% sensitive and specific at all concentrations.

Drug Resistance, Microbial↗
PubMed1992

Evaluation of commercial and standard methodology for determination of oxacillin susceptibility in Staphylococcus aureus.

Agar dilution with and without 4% NaCl, broth microdilution with 2% NaCl, the dried MicroScan Rapid Positive MIC 1 panel (Baxter Health Care Corp., West Sacramento, Calif.), the Vitek GPS-SA card (Vitek Systems, Hazelwood, Mo.), and the oxacillin agar screen plate were compared with a DNA probe encoding the mec gene for their abilities to detect oxacillin resistance in 506 clinical isolates of Staphylococcus aureus. The results of testing for the mec gene showed that there were 254 oxacillin-resistant and 252 oxacillin-susceptible isolates of S. aureus. There were 14.2% very major errors with Vitek (a resistant isolate was interpreted as susceptible) and 6.7% very major errors with MicroScan. Fewer major errors were seen: 0.8% with MicroScan (a susceptible isolate was interpreted as resistant) and 0.4% with Vitek. No very major errors but 2.4% major errors occurred by agar dilution with 4% NaCl supplementation, whereas there were 0.8% very major and 0.4% major errors without 4% NaCl supplementation. By broth microdilution there were 2.0% very major and 0.8% major errors. The results of the oxacillin agar screen plate method were 100% concordant with those of the mec gene probe method.

DNA Probes↗
PubMed1992

Broth microdilution testing of Haemophilus influenzae with haemophilus test medium versus lysed horse blood broth. Canadian Haemophilus Study Group.

Broth microdilution testing of 702 community-acquired isolates of Haemophilus influenzae from across Canada was performed with both Mueller-Hinton broth supplemented with 3% lysed horse blood broth (LHB) (BBL Microbiology Systems, Cockeysville, Md.) and haemophilus test medium (HTM). The prevalence of beta-lactamase production was found to be 26% with no regional variation. MICs determined with LHB tended to be higher than those with HTM, but interpretive errors due to these differences were observed only rarely with trimethoprim-sulfamethoxazole (n = 5), cefaclor (n = 8), and cefamandole (n = 3). The interobserver variability in MIC determinations was found to be greater when LHB was used than when HTM was used. There was no difference in intraobserver variability between the two medium formulations. beta-Lactamase-positive isolates developed false resistance to amoxicillin-clavulanate 2 weeks after microdilution panels of both types of medium were stored at -20 degrees C but not when panels were stored at -70 degrees C. In conclusion, this study supports the use of HTM rather than LHB for sensitivity testing of H. influenzae because of its lower rate of interobserver variability and its ability to support the growth of these organisms, which is comparable to that of LHB.

Amoxicillin↗
PubMed1992

Lung transplantation of ventilator-dependent patients. The Washington University Lung Transplantation Group.

During the last few years, lung transplantation has been extended to patients with a variety of end-stage lung diseases, but recipient selection guidelines have remained relatively strict. Ventilator-dependent patients have traditionally been considered poor candidates for transplantation. However, patients who have been thoroughly evaluated and accepted for transplantation and subsequently develop respiratory failure caused by progression and/or exacerbation of their underlying disease and recipients who experience respiratory failure caused by graft failure may be suitable candidates while ventilator-dependent if no other major complications or contraindications arise before a donor organ becomes available.

Adult↗
PubMed1992

Prospective randomized clinical trial comparing brachytherapy and laser photoablation for palliation of esophageal cancer.

Twenty-three consecutive patients with advanced esophageal cancer were randomized to receive either endoluminal irradiation or laser photoablation treatment. Initial improvement in dysphagia scores was observed in 83% (brachytherapy) and 91% (laser). This improvement in dysphagia was maintained at 2 months in 75% (brachytherapy) and 81% (laser). Performance scores improved in 33% (brachytherapy) and 36% (laser). Both treatments were well tolerated, required a minimum of inpatient treatment time, and allowed patients to die without terminal admission to district referral centers. Retreatments were three times as common with laser therapy, but the frequency of treatment failures was equal. Minor complications, especially transient early dysphagia, was more common in the brachytherapy group, although the only major complication (perforation) occurred in the laser group. No procedure-related deaths occurred in either group.

Aged↗
PubMed1992

An endemic strain of Staphylococcus haemolyticus colonizing and causing bacteremia in neonatal intensive care unit patients.

Coagulase-negative staphylococci are now the major cause of bacteremia in neonatal intensive care units. To date, coagulase-negative staphylococci causing neonatal infections have been found to be distinct when typed by standard techniques. To determine whether or not an endemic strain could be identified using more discriminatory techniques, we characterized coagulase-negative staphylococci isolates obtained from a prospective study of coagulase-negative staphylococci bacteremia in a neonatal intensive care unit during 1984 through 1985, by standard techniques supplemented with DNA-DNA hybridization and restriction endonuclease analysis. We typed 58 strains that were isolated from 52 episodes of bacteremia in 38 neonates. There were 46 isolates of Staphylococcus epidermidis. Three pairs of strains were identical, and each strain was from a different patient. There were 12 isolates of Staphylococcus haemolyticus. Ten were identical, referred to as strain TOR-35, and had been isolated from eight different infants. Characterization of strains obtained in 1986 from a prospective study of coagulase-negative staphylococci-colonizing neonates admitted to the same neonatal intensive care unit found the TOR-35 strain had colonized 6 of 17 neonates by day seven. A point prevalence survey of all neonates in the same neonatal intensive care unit in 1990 found 5 of 30 neonates to be colonized with the TOR-35 strain. Therefore, we were able to identify an endemic strain of S haemolyticus that caused multiple episodes of bacteremia during a 6-month period and remained present in the same environment for a 5-year period.

Anti-Bacterial Agents↗
PubMed1992

Morbidity, mortality, and early results of single versus bilateral lung transplantation for emphysema.

Both single lung transplantation and bilateral lung transplantation have been successful in patients with chronic obstructive pulmonary disease. Limited availability of donor lungs dictates wider use of single lung transplantation as long as this procedure provides a comparable functional result at less risk. Early morbidity, mortality rates, and functional results were compared in 32 consecutive patients undergoing either single or bilateral lung transplantation for end-stage chronic obstructive pulmonary disease. When pretransplantation and posttransplantation values of forced expiratory volume in 1 second, single breath diffusing capacity, total lung capacity, arterial oxygen tension, and 6-minute walking distance were compared, statistically significant improvement (p less than 0.01) was seen in both groups. However, significantly higher values (p less than 0.01) were attained for forced expiratory volume in 1 second, single breath diffusing capacity, and arterial oxygen tension in the bilateral transplantation group than in the single lung transplantation group. Patients receiving bilateral lung transplants were at greater risk for postoperative complications, especially cardiac arrhythmias and bronchial anastomotic defects. Actuarial survival for the single lung transplantation group was 93% at 1 year, versus 87% at 6 months and 71% at 1 year for the bilateral lung transplantation group. The optimal transplantation procedure for patients with chronic obstructive pulmonary disease has not been determined. Longer follow-up periods are needed to define better the roles of bilateral and single lung transplantation in this group of patients.

Age Factors↗
PubMed1991

How long should catheter-acquired urinary tract infection in women be treated? A randomized controlled study.

OBJECTIVE: To determine the optimal management of catheter-acquired bacteriuria after short-term catheter use in women. PATIENTS: Asymptomatic patients (119) with catheter-acquired bacteriuria were randomly assigned to receive no therapy, a single dose (320-1600 mg) of therapy with trimethoprim-sulfamethoxazole, or 10 days (160-800 mg twice daily) of therapy. Thirty-two patients with lower tract symptoms alone received a single dose or 10 days of therapy, and 10 patients with upper tract symptoms or signs received 10 days of therapy. MAIN RESULTS: The mean and median durations of catheter use were 6 and 4 days, respectively. Bacteriuria resolved within 14 days without therapy in 15 of 42 (36%; 95% CI, 21% to 51%) asymptomatic patients. Seven of the remaining patients developed symptoms. Single-dose therapy resolved infection in 30 of 37 patients (81%; CI, 68% to 94%); 10 days of therapy resolved infection in 26 of 33 (79%; CI, 65% to 93%). For patients with lower tract symptoms alone, resolution rates with single-dose therapy or 10 days of therapy were similar (11 of 14 [79%] and 13 of 16 [81%], respectively). Ten days of therapy resolved infection in 6 of 9 (67%) patients with upper tract symptoms. Infection was resolved more often in women who were less than or equal to 65 years than in older women (62 of 70 [89%] versus 24 of 39 [62%]; P less than 0.001). Bacteriuria resolved spontaneously more frequently in younger (14 of 19 [74%] compared with 1 of 23 older women [4%]; P less than 0.001). Single-dose therapy resolved infection in 31 of 33 (94%) patients who were less than or equal to 65 years. CONCLUSIONS: Asymptomatic bacteriuria after short-term catheter use frequently becomes symptomatic and should be treated. For asymptomatic patients and patients with lower tract symptoms alone, single-dose therapy was as effective as 10 days of therapy; it was very effective in women who were less than or equal to 65 years. Bacteriuria resolved spontaneously within 14 days after catheter removal more commonly in women who were less than or equal to 65 years and both types of therapy were less effective in older women.

Adult↗
PubMed1991

Bilateral sequential lung transplantation: the procedure of choice for double-lung replacement.

We recently described a technique for bilateral sequential lung transplantation that replaces the en bloc double-lung operation, a procedure that was accompanied by frequent problems with airway healing. Twenty-seven patients have undergone 28 bilateral sequential lung transplantations over the past 14 months. Eighteen patients had transplantation because of end-stage emphysema; 6, cystic fibrosis; and 1 each, obliterative bronchiolitis, usual interstitial pneumonitis with pulmonary fibrosis, and bronchiectasis. Cardiopulmonary bypass was used electively in the first 5 patients until it was recognized that the procedure could be done safely without it, and in only 3 additional recipients has it been employed. Mean ischemic time for the first lung was 276 +/- 43 minutes and for the second lung, 410 +/- 64 minutes. There have been five deaths, three in the postoperative period (11% operative mortality) and two late. The other patients are alive and well and do not require oxygen 2 to 15 months after transplantation. Mean forced expiratory volume in 1 second rose from 16% +/- 8% of predicted to 84% +/- 17% at 12 weeks. Six-minute walk values increased from a mean of 251 +/- 91 m to 666 +/- 42 m at 24 weeks. The excellent exposure afforded to both hemithoraces by the thoracosternotomy incision and the rare need of cardiopulmonary bypass have allowed us to offer the option of transplantation to patients who formerly would have been turned down because of previous pulmonary resection or pleurectomy. On four occasions, ventilator-dependent patients underwent successful transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗