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Biomedical subjects

A E Simor

Publications and source records attributed to A E Simor.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1991

Periodontitis as an early presentation of HIV infection.

OBJECTIVE: To determine whether the presence of rapidly progressive periodontitis (RPP) in people at high risk for acquired immunodeficiency syndrome (AIDS) may be the first symptom of previously unrecognized human immunodeficiency virus (HIV) infection. DESIGN: Case series. SETTING: Dental clinic. PATIENTS: Twenty patients who presented or were referred to the dental clinic over 6 months for the treatment of unexplained RPP and were at high risk for AIDS. OUTCOME MEASURES: Diagnosis of HIV infection: identification of candidal organisms in cytologic smears, determination of complete and differential blood counts and of ratio between T4 (helper) and T8 (suppressor) lymphocytes, and performance of HIV antibody assays. MAIN RESULTS: All of the patients were men, although sex was not an inclusion criterion. Sixteen (80%) of the 20 patients were found to have HIV infection. Four had been aware that they were HIV positive: two admitted it only when their T4:T8 ratio was known and the other two when the T4:T8 test was explained or requested. Fifteen of the patients were homosexual, three came from AIDS-endemic areas, and two had hemophilia. The RPP was responsible for alveolar bone loss in all of the patients. One patient lost bone in one site because of localized osteomyelitis. Only five patients had concurrent candidal overgrowth, and three had Kaposi's sarcoma. The mean T4:T8 ratio was 0.57 (standard deviation 0.52). CONCLUSIONS: These findings suggest that periodontal disease may be one of the first clinical presentations of previously undiagnosed HIV infection. Thus, patients at high risk for AIDS who present with aggressive periodontal disease should be investigated for possible HIV infection. However, further, prospective studies are required to confirm the contention that RPP is one of the first signs of HIV infection or AIDS.

Adult↗
PubMed1991

Two years of infection surveillance in a geriatric long-term care facility.

Prospective infection surveillance was carried out for 2 years on two selected units of an 800-bed geriatric long-term care facility. Information was obtained by discussion with attending medical and nursing staff members, chart review, and review of laboratory data. Unit A houses 47 ambulatory Home for the Aged (nursing home) residents (70% female) with a mean age of 89 years. Unit B, for patients requiring chronic hospitalization, houses 32 residents (60% female) with a mean age of 77 years. The infection rates per 1000 patient-days on units A and B were 1.77 and 9.45, respectively. The higher infection rate on unit B was probably due to the presence of a more debilitated patient population. The most common sites of infection on both units were respiratory tract, urinary tract, skin, and soft tissue. The major goals of surveillance in long-term care facilities should be to aid in early detection of outbreaks and to identify preventable endemic infections. Definitions of infection and methods of surveillance that take into account the unique characteristics of elderly subjects residing in long-term care facilities with relatively limited resources need to be developed.

Aged↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1990

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↗
PubMed1990

Campylobacter jejuni infection occurring during pregnancy.

Campylobacter infections occurring during pregnancy have been associated with spontaneous abortion, stillbirth, prematurity and neonatal sepsis, all ten Campylobacter jejuni infections diagnosed in the approximately 24,000 pregnant women attending a 520-bed hospital between January 1984 and December 1988 were reviewed. Nine women delivered healthy babies at term. In one case, Campylobacter infection at 28 weeks of gestation was associated with premature labour and delivery with subsequent neonatal sepsis and death. One other infant developed Campylobacter jejuni enterocolitis at 3 days of age. Although maternal Campylobacter jejuni infection tends to be mild and self-limited, there may be more serious complications for the fetus or neonate, especially if infection occurs before the third trimester of pregnancy.

Adult↗
PubMed1990

In vitro susceptibility of "Campylobacter upsaliensis" to twenty-four antimicrobial agents.

The in vitro susceptibility of 41 strains of "Campylobacter upsaliensis" to 24 antimicrobial agents was determined using a broth microdilution procedure. Most isolates were susceptible to the fluoroquinolones and beta-lactam antibiotics tested, but all strains were resistant to trimethoprim (MBCs greater than or equal to 128 micrograms/ml) and teicoplanin (MBCs greater than or equal to 32 micrograms/ml). These agents may be useful in a selective isolation medium for "Campylobacter upsaliensis".

4-Quinolones↗
PubMed1990

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↗
PubMed1990

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↗