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Biomedical subjects

A E Simor

Publications and source records attributed to A E Simor.

At least 73 records · Page 4Linked to original sources
PubMed1994

Use of the polymerase chain reaction for the detection of Chlamydia trachomatis from endocervical and urine specimens in an asymptomatic low-prevalence population of women.

The Amplicor Chlamydia trachomatis test is a polymerase chain reaction (PCR)-based methodology used for the detection of a cryptic plasmid found in C. trachomatis. It was evaluated in comparison with cell culture and the Microtrak II Chlamydia enzyme immunoassay (EIA) for the detection of C. trachomatis in urogenital specimens from women. Endocervical swabs were collected from 993 women attending the women's unit at the Mount Sinai Hospital in Toronto. In addition, concomitant first void urine specimens were collected from 394 of these women for PCR testing only. As compared with culture of the endocervical specimens, PCR and EIA had a sensitivity, specificity, positive predictive value and negative predictive value of 84.6%, 99.2%, 57.9%, and 99.8% and 61.5%, 99.7%, 72.7%, and 99.5%, respectively. As compared with the secondary gold standard of a positive culture and/or a positive PCR using a primer to the major outer membrane protein the sensitivity, specificity, positive, and negative predictive values for culture were 72.2%, 100%, 100%, and 99.5%, respectively. For the Amplicor PCR and EIA the results were 88.9%, 99.7%, 84.2%, and 99.9% and 61.1%, 99.9%, 91.7%, and 99.6%, respectively. When the urine PCR was compared with the same standard, the test had a sensitivity of 91.7% and a specificity of 99.5%. Based on this study the Amplicor C. trachomatis test was found to be sensitive and specific for the detection of C. trachomatis in both endocervical and urine specimens.

Adolescent↗
PubMed1994

Evaluation of three methods for the rapid identification of Staphylococcus aureus in blood cultures.

A total of 445 blood cultures containing Gram-positive cocci in clusters were tested for the presence of Staphylococcus aureus with the Accuprobe, heat-stable thermonuclease, and latex agglutination using Staphaurex. The results show that the Accuprobe, thermonuclease, and Staphaurex correctly identified 95, 96, and 62 of the 100 specimens containing S. aureus. The corresponding specificity for the methods was 99.1%, 100%, and 98.5%, respectively.

Bacteremia↗
PubMed1994

Successful treatment of systemic and local infections due to Exophiala species.

We report the successful treatment of three cases of infection due to Exophiala species. These organisms belong to the heterogeneous group of dematiaceous (darkly pigmented) fungi. Two cases of infection occurred in organ transplant recipients who were receiving immunosuppressive medications. Both of these infections remained localized to the subcutaneous tissues and were successfully treated with surgical excision of the lesions. We also describe what is to our knowledge the first reported case of prosthetic valve endocarditis due to Exophiala castellanii that was managed with a combination of medical and surgical therapies. Exophiala species remain an uncommon cause of infection. However, as the population of immunocompromised patients continues to grow and further improvements in the microbiological techniques for identification of these fungi occur, these organisms will be recognized with increasing frequency as a cause of human disease.

Adult↗
PubMed1994

Influenza A outbreak in a nursing home: the value of early diagnosis and the use of amantadine hydrochloride.

An outbreak of respiratory tract infection due to influenza A virus occurred in February 1994 among residents of an 88-bed long term care facility in Toronto, Ontario. Eighteen confirmed and four probable cases of influenza were identified for an attack rate of 25%. Seventy-one per cent of the residents were known to have been immunized with trivalent influenza vaccine, but vaccine efficacy was determined to be only 32%. Influenza A viral antigen was rapidly detected by immunofluorescence microscopy of nasopharyngeal swabs, and amantadine hydrochloride was started in 76 residents within 48 h of recognizing the outbreak. Only two of the residents (3%) at risk became ill more than 48 h after amantadine was started. Amantadine was discontinued in four residents (5%) because of adverse effects (agitation, confusion, unsteady gait). In conclusion, rapid identification of the outbreak and prompt administration of amantadine hydrochloride prophylactically appears to be safe and effective in preventing further spread of influenza A.

Amantadine↗
PubMed1993

A cluster of surgical wound infections due to unrelated strains of group A streptococci.

Group A streptococci account for less than 1% of all surgical wound infections but are an important cause of nosocomial outbreaks. We report here a cluster of four group A streptococcal infections that occurred within an 11-day period on a single surgical service. The index case presented with toxic shock-like syndrome. Epidemiologic investigation did not identify any relationship between infections. Restriction endonuclease analysis and M and T typing found the four isolates to be unrelated. Restriction endonuclease analysis is a useful tool for determining relatedness of nosocomial isolates of group A streptococci.

Cluster Analysis↗
PubMed1993

Severe invasive group A streptococcal infections in Ontario, Canada: 1987-1991.

During the past few years, there has been an apparent increase in serious infections due to group A streptococci (GAS) worldwide. We describe our experience with severe invasive GAS infections in Ontario, Canada, during the past 5 years (February 1987 through December 1991). A case was defined as the isolation of GAS from blood or normally sterile tissue in association with hypotension (systolic blood pressure, < 90 mm Hg). Fifty cases were identified in patients ranging in age from 4 to 100 years (median age, 47 years); 29 (58%) of the patients died. A primary focus of infection was identified in 38 cases (76%), with soft tissue being the site involved most frequently (68%). No focus of infection was found in 12 patients, and 36 patients (72%) were bacteremic. Complications included acute respiratory distress syndrome (21 of 50), acute renal failure (20 of 50), hypocalcemia (19 of 24), elevated creatinine kinase values (21 of 27), coagulation abnormalities (15 of 21), and hepatitis (15 of 24). Eleven cases (22%) were nosocomial; one of these was secondary to another nosocomial case. Thirty-three isolates were available for M and T typing and for determination of the presence of the genes for streptococcal pyrogenic exotoxin (SPE). The most frequent types were M1T1 (10) and M12/T12 (8). Twelve isolates possessed the speA gene, and 16 isolates had the speC gene. Only three isolates possessed both speA and speC. All isolates possessed the speB gene.

Adolescent↗
PubMed1993

Infection due to Clostridium difficile among elderly residents of a long-term-care facility.

In a study of the epidemiology of infection due to Clostridium difficile at long-term-care facilities, we conducted point-prevalence surveys and obtained stool samples from residents receiving antibiotics and from those developing diarrhea during 1 year at a 350-bed nursing home and an adjoining 280-bed chronic-care hospital. C. difficile and/or its cytotoxin was detected in 236 specimens from 94 residents. Only 16 (17%) of these 94 individuals had diarrhea at the time C. difficile was detected. The prevalence of C. difficile infection ranged from 2.1% to 8.1% in the nursing home and from 7.1% to 14.7% in the hospital. The organism was recovered from six (8.8%) of 68 residents receiving antibiotics, and four of the six developed antibiotic-associated diarrhea. The receipt of antibiotic treatment within the previous 8 weeks (odds ratio [OR], 7.9), the presence of a nasogastric or gastrostomy feeding tube (OR, 6.5), urinary and fecal incontinence (OR, 2.5), and the presence of more than three underlying diseases (OR, 2.0) were statistically significant independent variables associated with C. difficile infection. Typing of isolates by restriction-endonuclease analysis indicated that most C. difficile infections at this long-term-care facility were associated with endogenous enteric carriage of the organism, with little evidence of cross-infection.

Aged↗
PubMed1993

Identification and characterization of multiple species of vancomycin-resistant enterococci, including an evaluation of Vitek software version 7.1.

A total of 374 clinical isolates of Enterococcus spp. were characterized to determine the species distribution and vancomycin resistance. The ability of the Vitek system (bioMerieux Inc, Hazelwood, St. Louis, Mo.) to identify enterococci to the species level and to recognize vancomycin resistance by using computer software version 7.1 was evaluated. Conventional methods were used for identification and agar dilution was used for susceptibility testing, the results of which were as follows (presented as number of vancomycin-resistant isolates/number of members of that species identified): 219/234 E. faecium, 9/112 E. faecalis, 2/3 E. mundtii, 0/1 E. durans, 0/1 E. hirae, 0/1 E. raffinosis, and 0/1 E. avium. Ten enterococci were in the vancomycin-intermediate category (six E. gallinarum, two E. casseliflavus, and one each of E. faecium and E. faecalis). The Vitek GPI card correctly identified 98% of E. faecium isolates, 99% of E. faecalis isolates, and only two isolates of other enterococcal species. The GPS-TA card was 98% sensitive and 95% specific for the detection of vancomycin resistance, generating a total of four very major (1.6%) and five minor errors (1.3%).

Drug Resistance, Microbial↗
PubMed1993

Utilization review of the use of BACTEC PLUS high-volume blood culture bottles.

The BACTEC PLUS 26 (NR26) (Becton Dickinson, Towson, Md.) high-volume blood culture bottle replaced the less expensive smaller-volume NR6A bottle in our hospital. An audit carried out several months after their introduction revealed that only 17.5% of the NR26 bottles received the required blood volume. Several audits and educational programs were required in order to achieve a compliance rate of > 60%.

Bacteremia↗
PubMed1993

Rapid detection of infectious mononucleosis-associated heterophile antibodies by a novel immunochromatographic assay and a latex agglutination test.

A novel immunochromatographic assay, the CARDS O.S. MONO test (Pacific Biotech, San Diego, Calif.), and a latex agglutination test, the Infectious Mononucleosis Kit (Unipath Ltd., Hampshire, United Kingdom) were compared with the Paul-Bunnell-Davidsohn test. Of the 957 serum specimens studied, 78 were positive and 879 were negative by the Paul-Bunnell-Davidsohn test. After discrepancies were resolved by determining Epstein-Barr virus serology, the sensitivities of the CARDS O.S. MONO test and the Infectious Mononucleosis Kit were 91.0 and 96.2%, respectively, and both tests had a specificity and a positive predictive value of 100% and a negative predictive value and overall agreement of greater than 99%. The results show that both tests can accurately detect infectious mononucleosis-associated heterophile antibodies.

Adolescent↗
PubMed1993

A study of the epidemiology of an endemic strain of staphylococcus haemolyticus (TOR-35) in a neonatal intensive care unit.

Coagulase-negative staphylococci (CNS) are among the most prevalent microorganisms that colonize and cause sepsis in neonatal intensive care units (NICU). We had previously identified a strain of CNS, Staphylococcus haemolyticus (TOR-35), in the NICU at Mount Sinai Hospital, that had been repeatedly isolated from blood cultures from neonates. We therefore carried out a prospective study to determine the frequency and time of colonization and the frequency of bacteremia in neonates over a 3.5 month period. This was accomplished by obtaining surface swabs within 1 h of birth and on days 3, 5, and 7 and by characterizing all blood culture isolates of CNS. We also determined what percentage of neonatal CNS bacteremias were due to this strain, between January 1, 1987 and December 31, 1990, by retrieving and typing all stock cultures of CNS from that period. All isolates were typed by species identification and antimicrobial susceptibility profile code. There were 76 (38%) neonates that became colonized with the TOR-35 strain at some time during their NICU stay. Lower birth weight was associated with colonization (p < 0.001), as was lower gestational age (p < 0.001). Only 1 neonate had a positive blood culture isolate for the TOR-35 strain during the prospective study. Of the 4 years of neonatal bacteremias that were studied retrospectively, there were 252 episodes of CNS bacteremia, of which 27 (11%) were due to the TOR-35 strain. The TOR-35 strain has become endemic in our NICU and appears to selectively colonize premature, low birth weight newborn infants, but only infrequently causes bacteremia.

Bacteremia↗
PubMed1993

Prosol-chlorhexidine irrigation reduces the incidence of bacteremia during ultrasonic scaling with the Cavi-Med: a pilot investigation.

The purpose of this pilot investigation was to determine whether the incidence of bacteremia following subgingival ultrasonic scaling and root planing could be reduced by the use, pre- and intraoperatively, of an irrigant containing 0.12 per cent chlorhexidine (CHX); Prosol. Individuals having evidence of significant periodontal disease (minimum of seven sites per quadrant 4.0 mm and bleeding on probing) were entered into this study. By use of a random number table, patients were assigned to either the experimental or control groups. The procedures, as described below, were carried out in a double blind fashion so that neither the investigator nor the patient was aware of whether Prosol or placebo was being used. The placebo solution was flavored to make it indistinguishable from Prosol. Patients were first anesthetized. Their gingival crevices were then irrigated using the Cavi-Med ultrasonic scaler. At this point, the ultrasonic action was not activated. Ten minutes later, ultrasonic scaling and root planing with the Cavi-Med unit were begun with a continuous flow of either the placebo or control solutions. Blood samples were taken preoperatively, while postoperative samples were taken one minute after completing the scaling of each quadrant and then 10 minutes after scaling the second quadrant. Routine aerobic and anaerobic bacterial culture methods were used to identify viable blood-borne bacteria. The results show that there was no difference in the distribution or presentation of periodontal disease between the experimental and control quadrants.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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

Prevalence of hepatitis B surface antigen, hepatitis C antibody, and HIV-1 antibody among residents of a long-term-care facility.

OBJECTIVE: To determine the prevalence of hepatitis B antigen (HBsAg), antibody to hepatitis C virus (anti-HCV), and antibody to human immunodeficiency virus (anti-HIV) among residents of a long-term care facility. DESIGN: Anonymous unlinked serosurvey. SETTING: Accredited university-affiliated long-term-care facility in Toronto with 300 chronic-care hospital patients, 350 nursing home residents, and 200 residents of a senior citizens' apartment complex. INTERVENTIONS: Sera from left-over blood samples obtained from residents in November 1990 were tested for HBsAg, anti-HCV, and anti-HIV using standard methods. RESULTS: A total of 508 sera were tested. The number (%) positive for HBsAg, anti-HCV, and anti-HIV, respectively were: 3(0.6%), 7(1.4%), and 0(0%). CONCLUSIONS: This is the first report defining rates of infection with bloodborne infective agents among residents of a long-term care facility. These results support the use of hepatitis B vaccine for medical and nursing staff and the implementation of universal precautions in long-term care facilities.

Aged↗
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↗