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Biomedical subjects

D E Low

Publications and source records attributed to D E Low.

At least 181 records · Page 10Linked to original sources

Comparison of the new MicroScan Pos MIC Type 6 panel and AMS-Vitek Gram Positive Susceptibility Card (GPS-TA) for detection of high-level aminoglycoside resistance in Enterococcus species.

We compared the MicroScan Pos MIC Type 6 panel and AMS-Vitek Gram Positive Susceptibility Card (GPS-TA) to agar dilution screen plates for the detection of high-level aminoglycoside resistance in 182 enterococcal isolates. The specificity of the two commercial systems was 100%, with the exception of one susceptible isolate found to be streptomycin resistant by the Vitek system. The MicroScan and Vitek systems had comparable sensitivities for the detection of gentamicin resistance (90 and 95% respectively) and streptomycin resistance (85 and 78%, respectively). These results suggest that screening tests such as agar dilution screen plates, broth dilution, or disk diffusion should continue to be used to detect high-level gentamicin and streptomycin resistance.

Anti-Bacterial Agents↗

Comparison of the Clearview Chlamydia test, Chlamydiazyme, and cell culture for detection of Chlamydia trachomatis in women with a low prevalence of infection.

Two antigen detection systems, Clearview Chlamydia (Unipath Ltd., Bedford, United Kingdom) and Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.), were compared with culture for the diagnosis of chlamydia infection in women attending gynecological clinics. Chlamydia trachomatis was isolated from 43 (4.5%) of the 965 women tested. In comparison with tissue culture, the Clearview Chlamydia and Chlamydiazyme tests had sensitivities of 79.0 and 74.4%, respectively, and both had a specificity of 99.6%. The results show that the Clearview Chlamydia test is comparable to Chlamydiazyme for the detection of C. trachomatis from endocervical specimens in a population with a low prevalence of infection.

Adolescent↗

A randomized study to determine complications associated with duration of insertion of heparin locks.

A randomized trial was conducted to assess the effect of leaving heparin locks in place longer than 72 hours. Three hundred and one patients were randomly assigned to one of two groups. Group A had the lock changed every 72 hours and Group B had the lock left in place up to 168 hours. Due to withdrawals following randomization, Group A contained 116 subjects and Group B 140 subjects. No significant differences were found between the two groups in relation to age, sex, medical condition, drug used, entries into the lock, minor complications, or incidence of phlebitis. The findings suggest that consideration could be given to extending insertion time up to 96 hours and possibly up to 118 hours.

Adult↗

Comparison of four stains and a urease test for rapid detection of Helicobacter pylori in gastric biopsies.

Gastric biopsies were obtained from 125 subjects to compare detection of Helicobacter pylori by culture, a rapid urease test and histopathologic examination using haematoxylin-eosin, Gram, Giemsa, Warthin-Starry silver and acridine orange stains. Helicobacter pylori was isolated from 39 specimens. Acridine orange and Giemsa were the most sensitive stains, detecting 85% and 79% of positive specimens respectively. All stains showed high specificity (97-100%). The sensitivity and specificity of the rapid urease test was 62% and 100% respectively. These stains or the rapid urease test may be useful for rapid detection of Helicobacter pylori in gastric biopsies.

Biopsy↗

Epidemiology of needlestick injuries in house officers.

Eighty-eight medical students, interns, and residents were surveyed to study the epidemiology of their percutaneous exposures to blood. Respondents described 159 injuries in 221 person-years (py) of exposure in hospital wards and 213 injuries in 166 py of exposure in operating rooms. Nearly all injuries (greater than 98%) were needlesticks; less than 5% were reported to occupational health services. Rates of ward-related injury were highest for students (0.97/py) and decreased during training. Most injuries were due to recapping of used needles. In contrast to ward-related injury, rates of operating room-related injury were relatively low for nonsurgical students and interns (0.3/py), higher for surgical students (1.36/py), and stable over surgical residency training (mean, 5.4/py). Virtually all surgical injuries occurred during suturing. Further research into mechanisms of needlestick injuries and product design for their prevention are needed.

Accidents, Occupational↗

Comparative in vitro activities of sparfloxacin (CI-978; AT-4140) and other antimicrobial agents against staphylococci, enterococci, and respiratory tract pathogens.

The in vitro activity of sparfloxacin (CI-978; AT-4140) was compared with those of other antimicrobial agents against isolates of staphylococci, enterococci, and various respiratory tract pathogens. Sparfloxacin was the most active drug tested against staphylococci (MIC for 90% of the strains tested [MIC90], 0.125 micrograms/ml) and enterococci (MIC90, 1.0 microgram/ml). It was also active against Haemophilus influenzae (MIC90, less than or equal to 0.06 microgram/ml), Moraxella (Branhamella) catarrhalis (MIC90, 0.125 microgram/ml), Streptococcus pneumoniae (MIC90, 0.5 microgram/ml), and Streptococcus pyogenes (MIC90, 1.0 microgram/ml).

4-Quinolones↗

Comparative in vitro activities of several new fluoroquinolones and beta-lactam antimicrobial agents against community isolates of Streptococcus pneumoniae.

The in vitro susceptibilities of 551 community isolates of Streptococcus pneumoniae from the Canadian province of Ontario to several new fluoroquinolones and beta-lactam antimicrobial agents were determined by a broth microdilution technique. Eight (1.5%) of these isolates were moderately susceptible (MICs, greater than or equal to 0.12 and less than or equal to 1.0 microgram/ml) to penicillin; none was resistant. Temafloxacin, ciprofloxacin, and ofloxacin (MICs for 90% of strains tested, between 1 and 2 micrograms/ml) were the most active fluoroquinolones tested, and BMY-28100 (MIC for 90% of strains tested, 0.25 microgram/ml) was the most active of the new beta-lactams tested.

4-Quinolones↗

Use of molecular typing to study the epidemiology of Serratia marcescens.

Although Serratia marcescens is a well-known nosocomial pathogen, investigation of its hospital ecology has been limited by the lack of available typing techniques. During an investigation of the occurrence of this organism in a neonatal intensive care unit, we evaluated a number of such techniques. Using a selective medium, we conducted prospective surveillance of neonatal rectal colonization and environmental contamination with S. marcescens. In 8 months of surveillance, 5.1% (20 of 394) of the infants admitted to the unit became colonized. Most sink surfaces and drains were also culture positive. Differences between isolates could not be detected in biotypes from a commercial identification system (MicroScan) or by antibiograms, total protein fingerprints, or plasmid profiles. Serogrouping and genomic DNA restriction endonuclease analysis revealed the presence of six strains that colonized infants and a similar number of environmental strains. These two methods were concordant, with the exception that genomic DNA analysis demonstrated lack of relatedness between some strains within the same serogroup. DNA restriction endonuclease analysis was practical and reliable. The differences this method detected between environmental and neonatal strains provided strong evidence that the environment was not an important reservoir for S. marcescens in our neonatal intensive care unit.

Cross Infection↗

Typing of Campylobacter pylori by bacterial DNA restriction endonuclease analysis and determination of plasmid profile.

Campylobacter pylori isolates from 37 symptomatic patients and 3 asymptomatic volunteers were examined by chromosomal DNA restriction endonuclease analysis and determination of plasmid profile. Restriction digests with HindIII, HaeIII, PvuII, and BglII produced clear and reproducible results that permitted discrimination between different strains. Only 35% of C. pylori isolates were found to have plasmid DNA. Isolates from different patients, including those from two pairs of siblings, had unique restriction patterns and plasmid profiles. Consecutive isolates obtained 1 year apart from each of two asymptomatic volunteers had identical restriction patterns and plasmid profiles, suggesting persistence of the same strain. A pair of isolates obtained one year apart from the third volunteer differed in plasmid DNA content but had similar chromosomal DNA restriction patterns. Plasmid profile determination and bacterial DNA restriction endonuclease analysis provide a reliable means of discriminating between different strains of C. pylori and may be useful for typing these organisms in epidemiologic studies.

Campylobacter↗

Evaluation of a commercial microtiter system (MicroScan) using both frozen and freeze-dried panels for detection of high-level aminoglycoside resistance in Enterococcus spp.

The MicroScan system was compared with agar dilution screen plates for the detection of high-level aminoglycoside resistance in 182 enterococcal isolates. Both the frozen Gram-Positive Combo Type 2 and the freeze-dried Type 5 panels were evaluated. The specificity of both panels for the detection of streptomycin and gentamicin resistance was 100%. However, the sensitivities for the detection of gentamicin and streptomycin resistance were 84 and 31%, respectively, for the Type 2 panels and 90 and 41%, respectively, for the Type 5 panels. The sensitivities of these panels for the detection of enterococcal high-level aminoglycoside resistance are inadequate for routine use.

Anti-Bacterial Agents↗

Antibody to cytotoxin in infection by Helicobacter pylori.

Gastrointestinal disease and colonization by Helicobacter pylori were determined in 36 asymptomatic volunteers and 30 symptomatic individuals undergoing endoscopy and biopsy. Serum antibody immunoglobulin G (IgG) and IgA to H. pylori were measured by enzyme-linked immunosorbent assay. Serum antibody to a cytotoxin produced by H. pylori was detected with a neutralization assay. Serum IgG was 95% predictive of infection by H. pylori, and serum IgA was 88% predictive. Antibody to the cytotoxin was detected in 12 of 18 infected individuals. Antibody to the cytotoxin was a highly specific (96%), but not a very sensitive (67%), indicator of infection by H. pylori. The neutralization assay was 87% predictive of infection. These data confirm the diagnostic value of serum antibody to H. pylori for the detection of infection. The toxin-neutralizing activity of sera from individuals infected with H. pylori suggests that the cytotoxin is produced in vivo. It may therefore contribute to disease associated with H. pylori.

Adult↗

Reproducibility of interpretation of Gram-stained vaginal smears for the diagnosis of bacterial vaginosis.

In the diagnostic microbiology laboratory, interpretation of Gram-stained slides of vaginal swab specimens is used to support the clinical diagnosis of bacterial vaginosis. The reproducibility with which technologists interpret these Gram-stained slides was evaluated by presenting, in coded fashion, 80 original slides and 80 duplicate slides of vaginal swab specimens to three technologists. They each interpreted the original slide twice and the duplicate slide from the same specimen once. Intraobserver and interobserver agreement was assessed by use of the weighted kappa statistic. Semiquantitation of Lactobacillus and Gardnerella morphotypes and a diagnosis of bacterial vaginosis showed the greatest intraobserver agreement, with kappa values ranging from 0.772 to 1.000. Interobserver agreement was also high for rating Lactobacillus morphotypes and clue cells (kappa values between 0.735 and 0.869) but decreased slightly for Gardnerella morphotypes and a diagnosis of bacterial vaginosis (kappa values between 0.656 and 0.800). These results indicate that there is good agreement for the interpretation of Gram-stained slides of vaginal swab specimens and that this method alone, without culture, can be used reliably to support the clinical diagnosis of bacterial vaginosis.

Bacterial Infections↗

The prevalence of Campylobacter pylori gastritis among asymptomatic adults.

To determine the prevalence of Campylobacter pylori colonization in the healthy population we studied 54 asymptomatic volunteers and 65 patients referred because of gastrointestinal symptoms. All subjects underwent gastroscopy and gastric biopsy. C. pylori was isolated from 6 volunteers (11%) and 36 patients (55%). Histologic evidence of inflammation was present in 98% of the culture-positive subjects. Linear regression analysis revealed that the prevalence of C. pylori colonization increased with age. There was no difference in the isolation rate between the two groups when adjusted for age. Four of the six culture-positive volunteers underwent repeat endoscopy and gastric biopsy 1 year later; despite remaining asymptomatic, all still had positive culture results and histologic evidence of gastritis. We conclude that the prevalence of C. pylori-associated gastritis among symptomatic patients increases with age and that the organism may be present in the gastrointestinal tract for prolonged periods without symptoms or evidence of disease progression.

Adult↗