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Biomedical subjects

A E Simor

Publications and source records attributed to A E Simor.

At least 37 records · Page 2Linked to original sources
PubMed2000

Evaluation of the BacT/Alert microbial detection system with FAN aerobic and FAN anaerobic bottles for culturing normally sterile body fluids other than blood.

We evaluated the BacT/Alert Microbial Detection System (Organon Teknika Corporation, Durham, NC, USA) by using FAN bottles compared to conventional culture methods for the recovery of microorganisms from normally sterile body fluids other than blood and dialysates. Clinically significant pathogens were isolated from 116 (11%) of 1, 099 consecutive specimens (80 from both conventional media and FAN bottles; 23 from FAN bottles only; 13 from conventional media only). Gram-positive cocci were more likely to be recovered from FAN bottles than from conventional media (p = 0.04). Contaminants were also more likely to have grown in FAN bottles (3%) than on conventional media (1%) (p = 0.04). The mean time to detection of significant pathogens was 20.9 h using FAN bottles as compared to 30. 9 h using conventional media (p = 0.0001). These results indicate that the BacT/Alert Microbial Detection System using FAN blood culture bottles improves the yield of clinically significant Gram-positive isolates from normally sterile body fluids with a reduced time to detection.

Anaerobiosis↗
PubMed2000

PCR detection of Escherichia coli O157:H7 directly from stools: evaluation of commercial extraction methods for purifying fecal DNA.

Rapid identification of Escherichia coli O157:H7 is important for patient management and for prompt epidemiological investigations. We evaluated one in-house method and three commercially available kits for their ability to extract E. coli O157:H7 DNA directly from stool specimens for PCR. Of the 153 stool specimens tested, 107 were culture positive and 46 were culture negative. The sensitivities and specificities of the in-house enrichment method, IsoQuick kit, NucliSens kit, and QIAamp kit were comparable, as follows: 83 and 98%, 85 and 100%, 74 and 98%, and 86 and 100%, respectively. False-negative PCR results may be due to the presence of either inherent inhibitors or small numbers of organisms. The presence of large amounts of bacteria relative to the amount of the E. coli O157:H7 target may result in the lower sensitivities of the assays. All commercial kits were rapid and easy to use, although DNA extracted with the QIAamp kit did not require further dilution of the DNA template prior to PCR.

Culture Media↗
PubMed2000

Evaluation of three rapid methods for detection of methicillin resistance in Staphylococcus aureus.

The probe-based Velogene Rapid MRSA Identification Assay (ID Biomedical Corp., Vancouver, British Columbia, Canada) and the latex agglutination MRSA-Screen (Denka Seiken Co., Tokyo, Japan) were evaluated for their ability to identify methicillin-resistant Staphylococcus aureus (MRSA) and to distinguish strains of MRSA from borderline oxacillin-resistant S. aureus (BORSA; mecA-negative, oxacillin MICs of 2 to 8 microgram/ml). The Velogene is a 90-min assay using a chimeric probe to detect the mecA gene. MRSA-Screen is a 15-min latex agglutination test with penicillin-binding protein 2a antibody-sensitized latex particles. We compared these assays with the BBL Crystal MRSA ID System (Becton Dickinson, Cockeysville, Md.) and with PCR for mecA gene detection. A total of 397 clinical isolates of S. aureus were tested, consisting of 164 methicillin-susceptible strains, 197 MRSA strains, and 37 BORSA strains. All assays performed well for the identification of MRSA with sensitivities and specificities for Velogene, MRSA-Screen, and BBL Crystal MRSA ID of 98.5 and 100%, 98.5 and 100%, and 98.5 and 98%, respectively. Three MRSA strains were not correctly identified by each of the Velogene and MRSA-Screen assays, but repeat testing with a larger inoculum resolved the discrepancies. The BBL Crystal MRSA ID test misclassified four BORSA strains as MRSA. Both the Velogene and the MRSA-Screen assays are easy to perform, can accurately differentiate BORSA isolates from MRSA isolates, and provide a rapid alternative for the detection of methicillin resistance in S. aureus in clinical laboratories, especially when mecA PCR gene detection is unavailable.

Bacterial Proteins↗
PubMed1999

Risk factors for pneumonia and other lower respiratory tract infections in elderly residents of long-term care facilities.

BACKGROUND: Little is known about the risk factors, outcome, and impact of pneumonia and other lower respiratory tract infections (LRTIs) in residents of long-term care facilities. OBJECTIVE: To determine the risk factors and the effect of these infections on functional status and clinical course. METHODS: Active surveillance for these infections was conducted for 475 residents in 5 nursing homes from July 1, 1993, through June 30, 1996. Information regarding potential risk factors for these infections, functional status, transfers to hospital, and death was also obtained. RESULTS: Two hundred seventy-two episodes of pneumonia and other LRTIs occurred in 170 residents during 228 757 days of surveillance for an incidence of 1.2 episodes per 1000 resident-days. Multivariable analysis revealed that older age (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.1-2.6 per 10-year interval; P = .01), male sex (OR, 1.9; 95% CI, 1.1-3.5; P = .03), swallowing difficulty (OR, 2.0; 95% CI, 1.2-3.3; P = .01), and the inability to take oral medications (OR, 8.3; 95% CI, 1.4-50.3; P = .02) were significant risk factors for pneumonia; receipt of influenza vaccine (OR, 0.4; 95% CI, 0.3-0.5; P = .01) was protective. Age (OR, 1.6 [95% CI, 1.0-2.5] per 10-year interval; P = .05) and immobility (OR, 2.6; 95% CI, 1.8-3.8; P = .01) were significant risk factors for other LRTIs, and influenza vaccination was protective (OR, 0.3; 95% CI, 0.2-0.4; P = .01). Residents with pneumonia (OR, 0.7; 95% CI, 0.3-1.4; P = .31) or with other LRTIs (OR, 0.5; 95% CI, 0.2-1.1; P = .43) were no more likely to have a deterioration in functional status than individuals in whom infection did not develop. CONCLUSIONS: Swallowing difficulty and lack of influenza vaccination are important, modifiable risks for pneumonia and other LRTIs in elderly residents of long-term care facilities. Our findings challenge the commonly held belief that pneumonia leads to long-term decline in functional status in this population.

Aged↗
PubMed1999

A comparison of model-building strategies for lower respiratory tract infection in long-term care.

Five strategies for creating predictive models of lower respiratory tract infection in residents of long-term care facilities were compared. A linear judgment model was derived by administering clinical vignettes to physicians who indicated the risk of infection based on the presence or absence of five predictor variables. A model based on physician consensus was created using the same variables. Three models based on empirical data (logistic regression, proportional hazards, and recursive partitioning) were created from a "derivation" sample of data from a cohort study of lower respiratory tract infections in nursing homes using the five predictor variables. All models were applied to a validation set and compared using receiver operating characteristic (ROC) curves. The data-derived and consensus models showed the highest discriminative ability while the linear judgment model showed inferior performance.

Canada↗
PubMed1999

Molecular analysis of the genetic variation among penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae serotypes in Canada.

Few studies have examined the genetic relatedness within and between serotypes of Streptococcus pneumoniae. Penicillin-susceptible S. pneumoniae (PSSP) isolates (n=170) and penicillin-resistant S. pneumoniae (PRSP) isolates (n=48) belonging to 13 different serotypes from across Canada were studied to further understand the molecular epidemiology of S. pneumoniae. PRSP of serotypes 6B, 14, and 19F appeared to be novel clones, differentiated by pulsed-field gel electrophoresis from the recognized international penicillin-resistant clones belonging to these serotypes. In addition, not all PRSP strains shared similar genetic backgrounds with PSSP strains of the same serotype, suggesting that in Canada, certain PRSP strains have emerged from new unique lineages of PRSP. Although there was significant heterogeneity among S. pneumoniae of different serotypes, certain serotypes (3, 7F, and 22F) appeared to be more clonally related despite having originated from different geographic regions.

Cluster Analysis↗
PubMed1999

Screening high-risk patients for methicillin-resistant Staphylococcus aureus on admission to the hospital: is it cost effective?

OBJECTIVES: To determine the cost-effectiveness of a policy of screening high-risk patients for methicillin-resistant Staphylococcus aureus (MRSA) colonization on admission to hospital. SETTING: 980-bed university-affiliated tertiary-care hospital. PATIENTS: Between June 1996 and May 1997, patients directly transferred from another hospital or nursing home, or who had been hospitalized in the previous 3 months, were screened for MRSA within 72 hours of hospital admission. DESIGN: Nasal, perineal, and wound swabs were obtained for MRSA screening using standard laboratory methods. Laboratory and nursing costs associated with screening patients for MRSA on admission to hospital were calculated. The costs associated with the implementation of recommended infection control measures for patients with MRSA also were determined. RESULTS: 3,673 specimens were obtained from 1,743 patients. MRSA was found on admission in 23 patients (1.3%), representing 36% of the 64 patients with MRSA identified in the hospital during the year. MRSA-colonized patients were more likely to have been transferred from a nursing home (odds ratio [OR], 6.4; P =.04) or to have had a previous history of MRSA colonization (OR, 13.1; P =.05). Laboratory and nursing costs were found to be $8.34 per specimen, for a total cost of $30,632 during the year. The average cost of implementing recommended infection control measures for patients colonized with MRSA was approximately $5,235 per patient. CONCLUSION: If early identification of MRSA in colonized patients prevents nosocomial transmission of the organism to as few as six new patients, the screening program would save money.

Aged↗
PubMed1999

Influenza vaccination in long-term-care facilities: structuring programs for success.

OBJECTIVES: To determine which influenza vaccination program characteristics were associated with high resident vaccination rates in Canadian long-term-care facilities (LTCFs). DESIGN: A cross-sectional survey consisting of a mailed questionnaire conducted in spring 1991. PARTICIPANTS: All 1,520 Canadian LTCFs for the elderly with at least 25 beds. RESULTS: The mean overall influenza vaccination rate in the 1,270 (84%) responding facilities was 79%. In multivariate analysis, the variables significantly associated with increased vaccination rates were: a single nonphysician staff person organizing the program, having more program aspects covered by written policies, the offering of vaccine to all residents, a policy of obtaining consent on admission that was durable for future years rather than repeating consent annually, and automatically administering vaccine to residents whose guardians could not be contacted for consent. Any encouragement to staff to be vaccinated had a significant impact on staff vaccination rates. CONCLUSION: Well-organized influenza vaccination programs increase the influenza vaccination rates of residents in Canadian LTCFs. Facilities need to develop resident vaccination programs further and to focus on vaccinating staff.

Aged↗
PubMed1999

Infection in hospitalized trauma patients: incidence, risk factors, and complications.

BACKGROUND: Several factors place victims of multiple trauma at increased risk for infection. The purpose of this study was to delineate the frequency of, types of, and risk factors for infection in hospitalized trauma patients. METHODS: Prospective surveillance for nosocomial infection was conducted for all trauma patients who were admitted for more than 24 hours to a tertiary-care regional trauma center between January 1 and December 31, 1996. RESULTS: A total of 563 patients (414 males) with a mean age of 40 years (range, 15-97 years) were followed. Most (86%) sustained blunt traumatic injuries. A total of 367 infections occurred in 209 (37%) patients for an incidence of 32.1/1,000 patient-days. The hospital stay of 37% of patients was complicated by at least one infection, involving the following sites: lower respiratory tract (28%), urinary tract (24%), surgical wound (18%), skin/soft tissue (13%), intra-abdominal (5%), primary bloodstream (5%), and other sites (8%). Infection was complicated by septic shock in 36 (10%) cases, acute respiratory distress syndrome in 32 (9%) cases, and multiorgan failure in 13 (4%) cases. Death was attributed to infection in four patients. In a multivariate analysis, infected patients were more likely to have been ventilated (odds ratio [OR] = 2.6; p<0.001), to have had multiple surgical procedures (OR = 2.8; p = 0.02), to have received multiple blood transfusions (OR = 2.3; p = 0.04), and to have had a spinal cord injury (OR = 5.0; p = 0.002). First surgical procedure within 24 hours of admission was protective (OR = 0.4, p = 0.001). CONCLUSION: Trauma patients are at high risk for developing infection. Identifying patients who are at increased risk for infection may allow for early intervention and subsequent decrease in infectious morbidity.

Adolescent↗
PubMed1999

Two nursing home outbreaks of respiratory infection with Legionella sainthelensi.

OBJECTIVE: To describe outbreaks of infection caused by Legionella sainthelensi occurring in older residents of two nursing homes and to determine risk factors for the development of infection. DESIGN: Descriptive epidemiology and a case-control study. SETTING: Two nursing homes (140 beds and 254 beds in nursing homes A and B, respectively) located in southern Ontario, Canada, experiencing outbreaks of respiratory tract infection in July and August 1994. SUBJECTS: Case-residents of the two nursing homes who met clinical and laboratory criteria for Legionella infection. Control-residents were defined as those who were in the homes during the outbreaks and were asymptomatic. MEASUREMENTS: Active surveillance was conducted in both nursing homes to identify symptomatic residents. Residents with fever or respiratory tract symptoms had nasopharyngeal swabs taken for viral antigen detection and culture, urine for Legionella antigen detection, and acute and convalescent serology for viruses, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella. Chest X-rays were performed, and an attempt was made to obtain blood and sputum cultures. Water samples from shower heads, faucets, and air conditioning units were collected for Legionella culture and polymerase chain reaction (PCR) assay. A case-control study was done to assess possible risk factors for legionellosis. RESULTS: Twenty-nine cases -- 17 in nursing home A; 12 in nursing home B - were identified. Four (14%) case-residents had documented pneumonia and four case-residents died. Univariate analysis revealed that a history of stroke (odds ratio (OR) 2.3 (95% CI, 1.0-5.3)), eating pureed food (OR 4.6 (95% CI, 1.6-12.7)), and having fluids administered with medication (OR 2.5 (95% CI, 1.0-5.9)) were significant risk factors. Cases were less likely to wear dentures (OR .4 (95% CI, .2-.9)) or to eat solid food (OR .3, (95% CI, .1-.6)). Only eating pureed food remained significant in a multivariable analysis (OR 4.6 (95% CI, 1.6-13.0, P = .01)). CONCLUSION: This report describes outbreaks of legionellosis in two nursing homes, representing the first reported outbreaks of infection caused by Legionella sainthelensi. The association with illness of dietary characteristics indicative of swallowing disorders suggests that aspiration was the most likely mode of infection. The diagnosis of legionellosis should be considered during outbreaks of respiratory infection in nursing homes.

Aged↗
PubMed1999

Synergy testing of vancomycin-resistant Enterococcus faecium against quinupristin-dalfopristin in combination with other antimicrobial agents.

Using checkerboard and time-kill assays, we evaluated the in vitro activity of quinupristin-dalfopristin (RP 59500) alone and in combination with five other antimicrobial agents against 12 clinical strains of vancomycin-resistant Enterococcus faecium (VREF). In time-kill studies, six VREF strains exhibited synergism with the combination of quinupristin-dalfopristin and doxycycline and three exhibited synergism with quinupristin-dalfopristin plus ampicillin-sulbactam. Combinations of quinupristin-dalfopristin with these and other agents warrant further clinical evaluation for the treatment of serious VREF infections.

Anti-Bacterial Agents↗
PubMed1998

Comparison of six rapid agglutination tests for the identification of Staphylococcus aureus, including methicillin-resistant strains.

Six rapid agglutination tests for the identification of Staphylococcus aureus were evaluated by testing 416 strains of staphylococci. The sensitivities and specificities of the tests were as follows: Staphyloslide, 97.7% and 99.3% respectively; Prolex Staph Latex, 96.9% and 93.6%; Staphaurex, 95.4% and 94.2%; Staphaurex Plus, 100% and 93.4%; Slidex Staph Plus, 98.9% and 99.3%; and Staphytect Plus, 99.6% and 88.2%. The three tests utilizing latex particles coated with staphylococcal capsular antibodies were better able to identify methicillin-resistant S. aureus, but only Staphyloslide and Slidex Staph Plus had adequate specificity.

Agglutination Tests↗
PubMed1998

Amphotericin B in lipid emulsion: stability, compatibility, and in vitro antifungal activity.

Newer formulations of amphotericin B (AmB) complexed with liposomes or lipid suspensions have been developed. Preliminary studies have suggested that AmB in Intralipid (IL) may be as effective as, but less toxic than, conventional formulations of AmB, but few data are available regarding its stability, compatibility, or in vitro antifungal activity. A compatibility study was done to evaluate the effects of AmB concentrations in IL containing either 10 or 20% soybean oil. The effects of temperature, shaking, and AmB and IL concentrations on the stability of AmB-IL suspensions were analyzed by visual inspection and liquid chromatography. The in vitro antifungal activity of AmB-IL, compared to that of AmB alone against reference strains of Candida species was determined by using a broth macrodilution method in accordance with National Committee for Clinical Laboratory Standards guidelines (M27-T). Samples of AmB-IL which were lightly shaken retained more than 90% of the AmB concentration over 21 days when stored at either 4 or 23 degrees C. Varying the AmB concentration did not appear to affect the stability of AmB-IL. However, a precipitate was formed when mixtures with more than 30% lipid as a proportion of the total volume were centrifuged. AmB-IL and AmB alone had similar in vitro antifungal activities against reference strains of yeasts. Further pharmacologic and clinical studies with AmB-IL are warranted, although AmB should not be combined with IL in concentrations capable of producing a precipitate.

Amphotericin B↗
PubMed1998

Application of multiplex PCR for detection of non-O157 verocytotoxin-producing Escherichia coli in bloody stools: identification of serogroups O26 and O111.

Primers were designed to amplify sequences of verocytotoxin genes and eaeA genes of Escherichia coli O26:H11, O111:H8, and O157:H7 in a multiplex PCR assay. This assay successfully detected E. coli O26:H11 in bloody stool specimens in which other enteric pathogens were not detected by culture-based methods. Rapid assays to detect non-O157:H7 verocytotoxin-producing E. coli is important to improve methods for the etiologic diagnosis of hemorrhagic colitis.

Adhesins, Bacterial↗
PubMed1998

Diagnosis of group A streptococcal necrotizing fasciitis by using PCR to amplify the streptococcal pyrogenic exotoxin B gene.

This study evaluated a PCR assay for detection of the streptococcal pyrogenic exotoxin B (speB) gene from tissue biopsy specimens of patients with necrotizing fasciitis. speB was detected in specimens from all 10 patients with necrotizing fasciitis due to group A streptococcus. The assay was negative for all 11 patients without culture or serologic evidence of streptococcal infection. These results suggest that the detection of speB by PCR may be useful for confirming group A streptococcal infection when cultures are negative or not available.

Bacterial Proteins↗