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Allison J McGeer

Publications and source records attributed to Allison J McGeer.

10 recordsLinked to original sources
PubMed2006

Appropriate measures of influenza immunization program effectiveness.

Groll and Thomson's evaluation of the effectiveness of Ontario's Universal Influenza Immunization Campaign used per capita cases of laboratory-confirmed influenza. We argue that these data are susceptible to various biases and should not be used as an outcome measure. Laboratory data are traditionally used to identify the presence of influenza activity rather than to identify levels of influenza activity. A better measure of viral activity is the proportion of influenza tests positive; whereas the weekly proportion of tests positive was relatively consistent, a marked increase over time in the numbers of laboratory-confirmed cases paralleled an increase in the number of tests performed. Regardless, for evaluating universal influenza immunization program effectiveness, other established and available measures employed in previous studies describing the epidemiology of influenza should be used instead of laboratory data.

Humans↗
PubMed2006

Verification of the IDI-MRSA assay for detecting methicillin-resistant Staphylococcus aureus in diverse specimen types in a core clinical laboratory setting.

The IDI-MRSA assay has a sensitivity of 96% and a specificity of 96% when used to screen patients at extranasal sites. This verification study used previously unverified swabs and was undertaken in a core medical laboratory using nonmicrobiology technologists trained in sample processing, molecular laboratory work flow, and PCR practice.

Humans↗
PubMed2005

Nosocomial acquisition of methicillin-resistant Staphylococcus aureus during an outbreak of severe acute respiratory syndrome.

OBJECTIVE: The four hospitals assessed in this study use active surveillance cultures for methicillin-resistant Staphylococcus aureus (MRSA) and contact precautions for MRSA-positive patients as part of routine infection control practices. The objective of this study was to determine whether nosocomial acquisition of MRSA decreased in these hospitals during an outbreak of severe acute respiratory syndrome (SARS) when barrier precautions were routinely used for all patients. DESIGN: Retrospective cohort study. SETTING: Three tertiary-care hospitals (a 1100-bed hospital; a 500-bed hospital; and an 823-bed hospital) and a 430-bed community hospital, each located in Toronto, Ontario, Canada. PATIENTS: All admitted patients were included. RESULTS: The nosocomial rate of MRSA in all four hospitals combined during the SARS outbreak (3.7 per 10,000 patient-days) was not significantly different from that before (4.7 per 10,000 patient-days) or after (3.4 per 10,000 patient-days) the outbreak (P = .30 and P = .76, respectively). The nosocomial rate of MRSA after the outbreak was significantly lower than that before the outbreak (P = .003). Inappropriate reuse of gloves and gowns and failure to wash hands between patients on non-SARS wards were observed during the outbreak. Increased attention was paid to infection control education following the outbreak. CONCLUSIONS: Inappropriate reuse of gloves and gowns and failure to wash hands between patients may have contributed to transmission of MRSA during the SARS outbreak. Attention should be paid to training healthcare workers regarding the appropriate use of precautions as a means to protect themselves and patients.

Cross Infection↗
PubMed2005

Genetic diversity among type emm28 group A Streptococcus strains causing invasive infections and pharyngitis.

Genome sequencing of group A Streptococcus (GAS) has revealed that prophages account for the vast majority of gene content differences between strains. Serotype M28 strains are a leading cause of pharyngitis and invasive infections, but little is known about genetic diversity present in natural populations of these organisms. To study this issue, population-based samples of 568 strains from Ontario, Canada; Finland; and Houston, Texas, were analyzed. Special attention was given to analysis of variation in prophage-encoded virulence gene content by a PCR-based method. Thirty and 29 distinct prophage-encoded virulence gene profiles were identified among pharyngitis and invasive infection isolates. Thirteen profiles, representing the majority of the strains, were shared between these two classes of isolates. Significant differences were observed in the frequency of occurrence of certain prophage toxin gene profiles and infection type. M28 strains are highly diverse in prophage-encoded virulence gene content and integration site, supporting the key concept that prophages are critical contributors to GAS genetic diversity and population biology. Nucleotide sequence variation in the emm gene (encodes M protein) was also examined. Only three allelic variants were identified in the hypervariable portion of the emm28 gene. All but one strain had the same inferred amino acid sequence in the first 100 amino acids of the mature M28 protein. In contrast, size differences in the emm28 gene and inferred protein due to variable numbers of C-terminal repeats were common. The presence of macrolide resistance genes (mefA, ermB, and ermTR) was analyzed by PCR, and less than 2% of the strains were positive.

Antigens, Bacterial↗
PubMed2004

Adverse effects of amantadine and oseltamivir used during respiratory outbreaks in a center for developmentally disabled adults.

BACKGROUND AND OBJECTIVES: Antiviral prophylaxis is recommended for the control of institutional influenza A outbreaks. In long-term-care institutions other than nursing homes, neither the seriousness of influenza nor the risks and benefits of antiviral prophylaxis is clearly understood. We studied the severity of illness due to influenza among adults residing in a center for the developmentally disabled and assessed adverse reactions to amantadine and oseltamivir prophylaxis. METHODS: Data were collected from the charts of consenting residents. Complications of upper respiratory tract illness were recorded. Potential adverse events were documented during amantadine and oseltamivir therapy, and during a baseline period with neither medication. RESULTS: The median age of the 287 participants was 46.4 years. Only 15 (5%) were older than 65 years, and 69 (24%) had chronic underlying medical illness placing them at high risk for influenza. Of the 122 residents with an upper respiratory tract infection, 16 (13%) developed pneumonia, 12 (9.8%) were hospitalized, and 5 (4%) died. Twenty-eight (25%) of 112 residents had an adverse neurologic event while receiving amantadine prophylaxis, compared with 3 (2.7%) receiving no antiviral medication and 5 (4.5%) receiving oseltamivir (P < .001). Sixteen percent of the residents discontinued amantadine due to adverse events; in contrast, adverse events were identified in 2.9% of the residents prescribed oseltamivir, and none discontinued therapy. CONCLUSIONS: Viral respiratory tract infections are associated with a high risk of complications in this population. The rate of adverse neurologic events associated with amantadine was significantly higher than that associated with oseltamivir.

Acetamides↗
PubMed2004

Resistance to antibiotics: administrative response to the challenge.

The authors discuss antibiotic resistance within a conceptual framework that illustrates the dynamic relationships among antibiotic, patient, and population factors. The complexity of these interactions makes it unlikely that any single intervention or approach will adequately address the problem of increasing rates of antibiotic resistance. A case study focused on Streptococcus pneumoniae in the context of community-acquired pneumonia provides a detailed examination of the manner in which antibiotic use, expenditures, and microbial resistance are affected by an administrative reimbursement restriction implemented by a single government payer.

Drug Costs↗
PubMed2003

Identification of severe acute respiratory syndrome in Canada.

BACKGROUND: Severe acute respiratory syndrome (SARS) is a condition of unknown cause that has recently been recognized in patients in Asia, North America, and Europe. This report summarizes the initial epidemiologic findings, clinical description, and diagnostic findings that followed the identification of SARS in Canada. METHODS: SARS was first identified in Canada in early March 2003. We collected epidemiologic, clinical, and diagnostic data from each of the first 10 cases prospectively as they were identified. Specimens from all cases were sent to local, provincial, national, and international laboratories for studies to identify an etiologic agent. RESULTS: The patients ranged from 24 to 78 years old; 60 percent were men. Transmission occurred only after close contact. The most common presenting symptoms were fever (in 100 percent of cases) and malaise (in 70 percent), followed by nonproductive cough (in 100 percent) and dyspnea (in 80 percent) associated with infiltrates on chest radiography (in 100 percent). Lymphopenia (in 89 percent of those for whom data were available), elevated lactate dehydrogenase levels (in 80 percent), elevated aspartate aminotransferase levels (in 78 percent), and elevated creatinine kinase levels (in 56 percent) were common. Empirical therapy most commonly included antibiotics, oseltamivir, and intravenous ribavirin. Mechanical ventilation was required in five patients. Three patients died, and five have had clinical improvement. The results of laboratory investigations were negative or not clinically significant except for the amplification of human metapneumovirus from respiratory specimens from five of nine patients and the isolation and amplification of a novel coronavirus from five of nine patients. In four cases both pathogens were isolated. CONCLUSIONS: SARS is a condition associated with substantial morbidity and mortality. It appears to be of viral origin, with patterns suggesting droplet or contact transmission. The role of human metapneumovirus, a novel coronavirus, or both requires further investigation.

Adult↗
PubMed2003

Risk factors for resistance to antimicrobial agents among nursing home residents.

The authors prospectively collected data on exposure to antimicrobial agents and susceptibility patterns among all clinical isolates of bacteria taken from 9,156 residents of 50 nursing homes in Canada and the United States in 1998-1999. Exposure to antimicrobial agents was measured during the 10 weeks prior to detection of targeted resistant bacteria in residents and compared with antibiotic exposure during a 10-week interval in individuals with sensitive organisms. These main effects were adjusted for infection-control and staffing covariates using multiple logistic regression modeling. Increased staffing of nursing homes with registered nurses (adjusted odds ratio (OR) = 0.79 (95% confidence interval (CI): 0.72, 0.87) per registered nurse per 100 resident-days) and use of antibacterial soap (adjusted OR = 0.40, 95% CI: 0.18, 0.90) were associated with reduced risk of methicillin-resistant Staphylococcus aureus in nursing home residents. An increase in the number of hand-washing sinks per 100 residents was shown to reduce the risk of trimethoprim-sulfamethoxazole (TMP/SMX)-resistant Enterobacteriaceae (adjusted OR = 0.94, 95% CI: 0.90, 0.98). Exposure to TMP-SMX and exposure to fluoroquinolones were significant risk factors for isolation of TMP-SMX-resistant Enterobacteriaciae (adjusted OR = 1.14, 95% CI: 1.06, 1.22) and fluoroquinolone-resistant Enterobacteriaciae (adjusted OR = 1.08, 95% CI: 1.04, 1.11), respectively. These findings suggest that increased staffing, more hand-washing sinks, and use of antimicrobial soap may reduce resistance to antimicrobial agents in long-term care facilities.

Anti-Bacterial Agents↗
PubMed2003

Emergence of macrolide resistance in throat culture isolates of group a streptococci in Ontario, Canada, in 2001.

Of 500 group A streptococci isolated from pharyngeal swabs, 72 (14.4%) were macrolide resistant, compared to 2.1% in 1997. Of these, 66 (92%) were of the M phenotype and 6 (8.3%) were of the MLS phenotype. Pulsed-field gel electrophoresis found that two clones, with patterns identical to those of serotypes M1 and M4, accounted for 19.4 and 68.1% of the macrolide-resistant isolates, respectively.

Anti-Bacterial Agents↗