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Biomedical subjects

A E Simor

Publications and source records attributed to A E Simor.

At least 55 records · Page 3Linked to original sources
PubMed1998

Bacterial meningitis in children and adults. Changes in community-acquired disease may affect patient care.

Despite improved understanding of how bacterial meningitis develops, the infection remains a potentially life-threatening emergency capable of causing significant morbidity and mortality. Since the introduction and widespread use of H influenzae type b vaccine in infancy and childhood in North America, the epidemiology of community-acquired bacterial meningitis has changed. S pneumoniae is now the most common cause in children and adults overall, although N meningitidis causes most disease in patients between ages 2 and 18 years. Broad-spectrum cephalosporins (eg, ceftriaxone, cefotaxime) are considered the agents of choice for empirical treatment of bacterial meningitis. However, use of these agents will have to be reconsidered if the incidence of invasive infection from drug-resistant S pneumoniae continues to increase. The role of adjunctive corticosteroid therapy needs to be better defined. Improved conjugate pneumococcal and meningococcal vaccines may soon make bacterial meningitis a preventable disease.

Adrenal Cortex Hormones↗
PubMed1997

Antifungal susceptibility testing of yeast isolates from blood cultures by microbroth dilution and the E test.

The results of microbroth dilution were compared with those of the E test for 169 yeast isolates tested for their susceptibility to antifungal agents. All isolates were tested by both methods against amphotericin B, ketoconazole, fluconazole, and itraconazole. The E test results generally correlated well with those obtained by the reference method. There was at least 80% agreement of minimum inhibitory concentration results within two dilutions for all yeast species and agents tested, except for Cryptococcus neoformans tested with fluconazole (8% agreement). The E test appears to be a suitable alternative antifungal susceptibility test method for yeasts, although improvements are required for testing Cryptococcus neoformans against fluconazole.

Antifungal Agents↗
PubMed1997

Risk factors, clinical features and outcome of Acinetobacter bacteremia in adults.

The medical records of 39 patients with Acinetobacter bacteremia identified in the period between 1985 and 1995 were reviewed. In 24 cases (62%) the bacteremia was considered to have been clinically significant. Most of the infections (79%) were nosocomial, and the majority of these were acquired in an intensive care unit. Ten (42%) patients developed septic shock complicating the bacteremia and 13 (54%) died. In most of these cases (85%), Acinetobacter bacteremia was thought to have caused or contributed to death. The following variables were associated with a greater risk of mortality: age > 65 years (OR = 16; p = 0.01); development of septic shock (OR = 22; p = 0.004); and the presence of coagulopathy (OR = 20; p = 0.03).

Acinetobacter↗
PubMed1997

Mycobacterium xenopi infection in patients with human immunodeficiency virus infection.

Mycobacterium xenopi is one of the most frequently isolated nontuberculous mycobacteria in Ontario, Canada. We reviewed the records of 28 human immunodeficiency virus (HIV)-infected patients from whom M. xenopi was isolated between 1982 and 1995. M. xenopi was recovered from respiratory specimens from 24 patients, most of whom had clinical and radiographic evidence of pulmonary disease. However, coexistent pulmonary infection due to other pathogens was found in 17 patients: Pneumocystis carinii (9 patients), cytomegalovirus (5), Haemophilus influenzae (2), Mycobacterium avium complex (2), Streptococcus pneumoniae (1), Staphylococcus aureus (1), Aspergillus species (1), and Histoplasma capsulatum (1). Three patients had bacteremia with M. xenopi, including two patients with pulmonary infection. Two of the bacteremic patients had chronic fever and a wasting syndrome. Twenty-one (75%) of the 28 patients were thought to be colonized, and seven patients (25%; of whom four had CD4 cell counts of < or = 50/mm3) were thought to have significant infection due to M. xenopi. Sixteen patients died, but in no case was death attributable to M. xenopi infection. In a region where M. xenopi is a relatively common mycobacterial isolate, the organism frequently colonizes HIV-infected patients. Significant disease occurs in those patients with more advanced HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1997

Nosocomial Neisseria meningitidis: molecular analysis of a clinical problem.

Over a 1-week period, Neisseria meningitidis serogroup B was recovered from two patients in the intensive-care unit (ICU). A cross-infection was presumed when one patient developed invasive meningococcal disease and another patient was found to be colonized. Investigation by molecular typing showed that these cases were not related, demonstrating the value of molecular typing when investigating potential cross-infections in a closed environment such as the ICU.

Cross Infection↗
PubMed1997

Antimicrobial susceptibilities of blood culture isolates obtained before and after the introduction of ciprofloxacin.

The in-vitro susceptibilities of 1658 blood culture isolates to ciprofloxacin and 13 other antimicrobial agents were determined, and compared with the results for isolates obtained before and after the availability of ciprofloxacin in 1989. Only six (0.6%) of 995 Enterobacteriaceae were resistant to the fluoroquinolones tested; all of the ciprofloxacin-resistant strains were isolated after 1989 (P = 0.04). No significant increase in ciprofloxacin resistance was found in Pseudomonas aeruginosa or Acinetobacter spp. No resistance to ciprofloxacin was found in 124 Staphylococcus aureus isolates prior to 1989, but five (2.4%) of 208 S. aureus strains recovered after 1989 were ciprofloxacin-resistant (P = 0.16). Rates of resistance to ciprofloxacin and other antimicrobial agents commonly used to treat bacteraemic infections have remained relatively low in this Canadian teaching hospital over the past 16 years.

Acinetobacter↗
PubMed1997

Investigation of a pseudo-outbreak of Nocardia asteroides infection by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA PCR.

Molecular strain typing by pulsed-field gel electrophoresis and by randomly amplified polymorphic DNA analysis was used to investigate a cluster of four Nocardia asteroides isolates associated with the BACTEC 460 TB system. An instrument motor drive misalignment resulted in inadequate needle sterilization and cross-contamination of BACTEC vials. This pseudo-outbreak illustrates the importance of proper BACTEC 460 needle sterilization and maintenance and confirms the usefulness of molecular typing methods for epidemiologic investigations.

Bacterial Typing Techniques↗
PubMed1996

Invasive group A streptococcal infections in Ontario, Canada. Ontario Group A Streptococcal Study Group.

BACKGROUND: Several reports suggest that the incidence of invasive group A streptococcal infections, including streptococcal toxic shock syndrome and necrotizing fasciitis, is increasing. METHODS: During 1992 and 1993 we conducted prospective, population-based surveillance of invasive group A streptococcal disease in Ontario, Canada. We reviewed clinical and laboratory records, searched for secondary cases of invasive disease, and cultured specimens from household contacts. RESULTS: We identified 323 patients with invasive group A streptococcal infections, for an annual incidence of 1.5 cases per 100,000 population. The rates were highest in young children and the elderly. Fifty-six percent of the patients had underlying chronic illness. Risk factors for disease included infection with the human immunodeficiency virus, cancer, diabetes, alcohol abuse, and chickenpox. The most common clinical presentations were soft-tissue infection (48 percent), bacteremia with no septic focus (14 percent), and pneumonia (11 percent). Necrotizing fasciitis occurred in 6 percent of patients, and toxic shock in 13 percent. The mortality rate was 15 percent overall, but it was 29 percent among those over 64 years of age (P<0.001) and 81 percent among those with toxic shock (P<0.001). Fourteen percent of the cases were nosocomial, and 4 percent occurred in nursing home residents, often in association with disease outbreaks. Invasive disease occurred in 2 household contacts of patients with infection, for an estimated risk of 3.2 per 1000 household contacts (95 percent confidence interval, 0.39 to 12 per 1000). CONCLUSIONS: The elderly and those with underlying medical conditions are at greatest risk for invasive group A streptococcal disease, toxic shock, and necrotizing fasciitis. Invasive steptococcal infection is associated with a substantial risk of transmission in households and health care institutions.

Adolescent↗
PubMed1996

Tuberculosis infection among staff at a Canadian community hospital.

OBJECTIVE: To determine risks for tuberculin skin-test conversion among employees of a community hospital in Ontario, Canada. DESIGN: Cohort morbidity study. SETTING: Of 14 metropolitan Toronto area hospitals surveyed for data on tuberculin skin-test conversions, only one provided tuberculosis (TB) test data on all employees. Between 1991 and June 1994, 24 patients were treated at this hospital for pulmonary TB. POPULATION STUDIED: The population at risk included those on staff from January 1991 through December 1993 who previously were skin-test negative; they were followed until the end of June 1994. Exposure was estimated (a) based on ranking departments according to an estimate of the number of hours of direct patient contact during a typical day, and (b) based on location of sputum-positive patients. OUTCOME MEASURE: Risks of skin-test conversion among hospital employees with documented prior negative skin tests. MAIN RESULTS: A total of 809 skin-test negative employees were followed for 2,084 person-years; 18 employees with skin-test conversions were identified. The overall conversion rate was 0.9% per year (0.86 per 100 person-years). After excluding two conversions attributed to contact with coworkers, the relative risk of conversion was 4.5 (5.5 after adjusting for age and gender) among those in the highest exposure category (> or = 4 hours per day), compared to those in departments ranked as having the lowest exposure (< 2 hours per day). Among those working in wards in which sputum-positive patients were treated, 2.4% converted; the risk of conversion was over six times greater than among those working on wards with no TB patients or in departments with no patient contact, of whom 0.4% converted. Among the emergency room staff, the department in which the greatest number of sputum-positive patients were treated, at least 5% of staff converted. In those instances in which conversions were associated with exposure to a specific TB patient, the involved patients had been in the hospital for at least 4 days prior to being isolated. CONCLUSIONS: These results indicate that even in a hospital with few admissions due to tuberculosis, skin-test conversions associated with occupational exposure may occur (Infect Control Hosp Epidemiol 1996; 17:29-35).

Adolescent↗
PubMed1996

An outbreak of fatal nosocomial infections due to group A streptococcus on a medical ward.

Group A streptococcus is an uncommon but important cause of nosocomial infections. Outbreaks of infection most often have occurred in surgical or obstetrical patients. We describe an outbreak of severe group A streptococcal infections that occurred on a medical unit of a community hospital. Within an 8-day period, three patients developed fatal nosocomial skin and soft-tissue infection due to group A streptococcus. Three nurses who had provided care to one or more of these patients subsequently developed streptococcal pharyngitis, and three other nurses were treated with antibiotics for pharyngitis (cultures not obtained). Patient isolates were serotype M-nontypeable, T-11, opacity factor-positive, and shared identical DNA profiles when typed by pulsed-field gel electrophoresis; staff isolates were not available for typing. To prevent further spread of infection, the ward was closed to new admissions, and symptomatic staff were treated with antibiotics and relieved of patient-care duties. This outbreak demonstrates the ability of group A streptococcus to spread rapidly in a hospital setting and to cause severe life threatening disease in hospitalized patients.

Cluster Analysis↗
PubMed1996

Canadian national survey of prevalence of antimicrobial resistance among clinical isolates of Streptococcus pneumoniae. Canadian Bacterial Surveillance Network.

The antimicrobial susceptibilities of 1,089 clinical isolates of Streptococcus pneumoniae obtained from 39 laboratories across Canada between October 1994 and August 1995 were determined. A total of 91 isolates (8.4%) demonstrated intermediate resistance (MIC, 0.1 to 1.0 microgram/ml) and 36 (3.3%) had high-level resistance (MIC, > or = 2.0 micrograms/ml) to penicillin. Penicillin-resistant strains were more likely to have been recovered from normally sterile sites (P = 0.005) and to be cross-resistant to several beta-lactam and non-beta-lactam antimicrobial agents (P < 0.05). These results indicate that there has been a recent significant increase in the prevalence of antibiotic-resistant S. pneumoniae in Canada.

Canada↗
PubMed1996

Evaluation of enzyme immunoassay for detection of salivary antibody to Helicobacter pylori.

The Helisal test is a quantitative enzyme immunoassay for the measurement of Helicobacter pylori-specific immunoglobulin G antibodies in saliva. This test was evaluated in comparison with culture and histopathologic examination of gastric biopsy specimens obtained from 195 patients who underwent 200 endoscopic procedures for the investigation of gastrointestinal symptoms. Forty-one (21%) patients were found to have peptic ulcer disease, and one other patient had a gastric carcinoma. H. pylori was detected in gastric biopsy specimens obtained from 98 (49%) of the procedures. The sensitivity, specificity, and positive and negative predictive values of the Helisal test were 81, 75, 76, and 80%, respectively. The test was negative for 16 (38%) of the 42 patients with peptic ulcer disease or a gastric malignancy diagnosed at endoscopy. These results suggest that the Helisal assay is only moderately accurate for the detection of H. pylori infection in symptomatic patients.

Adolescent↗
PubMed1996

Evaluation of nutritive capacities of 10 broth media.

Ten broth media were evaluated for their ability to support the growth of low inocula of selected fastidious aerobic, microaerophilic, and anaerobic bacteria. Thioglycolate medium USP (Oxoid, Basingstoke, England), cooked meat broth (Oxoid), and fastidious anaerobe broth (Quelab Laboratories Inc., Montreal, Quebec, Canada) were best able to support the growth of the greatest variety of organisms at the lowest inoculum tested (10(1) CFU). In most cases, incubation of these broths resulted in visible turbidity within 3 days. These three broth media were found to be equally suitable for use as an enrichment broth in the clinical laboratory.

Bacteria, Aerobic↗
PubMed1995

Influenza and pneumococcal vaccination and tuberculin skin testing programs in long-term care facilities: where do we stand?

OBJECTIVE: 1) To compare policies and procedures for distribution of influenza and pneumococcal vaccines to long-term care facilities for the elderly in Canada, 2) to determine vaccination rates of residents and staff, and 3) to describe vaccination and tuberculin skin testing programs in these facilities. DESIGN: A cross-sectional survey consisting of telephone interviews and a mailed questionnaire was conducted in the spring of 1991. Telephone interviews were conducted with provincial/territorial epidemiologists. The questionnaire was sent to all (N = 1.520) Canadian long-term care facilities for the elderly with > or = 25 beds. RESULTS: There were 1,270 responding facilities (84%). The mean overall influenza vaccination rate for residents was 78.5%. The mean vaccination rate was higher in those provinces in which the vaccine was paid for by the government (79% versus 71%; P = 0.002). Only 19% of facilities reported staff vaccination rates > 25%; rates again were higher in those provinces in which vaccine for staff was provided by the government. Pneumococcal vaccine was offered to residents in 12% of the facilities. The proportions of facilities with > 10% and > 75% of residents vaccinated were significantly higher in the provinces where the pneumococcal vaccine was recommended and paid for as compared with those where it was not (P < 0.001 for both). Tuberculin skin testing programs for residents existed in 360 long-term care facilities (28%) across the country. CONCLUSION: In 1990, the number of residents living in Canadian long-term care facilities who were vaccinated against influenza and Streptococcus pneumoniae was suboptimal. Staff influenza vaccination rates were very low across the country. Most facilities did not have a baseline tuberculin skin test status for their residents. Vaccination rates are higher in jurisdictions in which governments provide the vaccine without charge.

Bacterial Vaccines↗
PubMed1995

Comparison of E test and agar dilution for antimicrobial susceptibility testing of Stenotrophomonas (Xanthomonas) maltophilia.

Currently recommended dilution test methods for the determination of antimicrobial susceptibility of Stenotrophomonas (Xanthomonas) maltophilia are labor-intensive and often impractical in many clinical laboratories. We compared the E test with the agar dilution method for susceptibility testing of 176 clinical isolates of S. maltophilia against 16 antimicrobial agents. The MICs obtained by E test correlated well with those determined by the agar dilution method, with an overall agreement of 94%. Very major and major errors occurred infrequently (0.6 to 2.9%) when testing beta-lactam agents, tobramycin, trimethoprim-sulfamethoxazole, and fluoroquinolones. The E test was found to be accurate and easy to perform. For most antimicrobial agents tested against S. maltophilia, the E test is an acceptable alternative susceptibility test method.

Agar↗
PubMed1995

Outbreaks of gastroenteritis due to Norwalk-like virus in two long-term care facilities for the elderly.

In February 1993, outbreaks of gastroenteritis due to Norwalk-like viruses occurred simultaneously among the elderly residents of two long-term care facilities. Facility A instituted infection control measures that included increased surveillance, reinforcement of handwashing, keeping symptomatic residents in their rooms and relieving symptomatic staff of their work duties until 48 h after resolution of their symptoms. Facility B instituted a more stringent set of control measures that included all those implemented by facility A plus the following: staff from affected units were not permitted to work on other units, affected units were closed to new admissions, enteric precautions were instituted for ill residents, residents were restricted to their own units and education was provided to staff and residents about gastroenteritis. Facility A had an attack rate of 9%; the attack rate for facility B was 11% (P = 0.38). The duration of the outbreak was 29 days in facility A and 24 days in facility B. The impact these infection control measures had on the course of the outbreaks is difficult to determine. However, it is doubtful that the more stringent measures implemented at facility B had any greater effect on the course of the outbreak. A better understanding of the precise mechanisms of viral transmission is required in order to determine the most appropriate control measures for gastroenteritis due to Norwalk-like viruses in long term care facilities.

Aged↗