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Allison McGeer

Publications and source records attributed to Allison McGeer.

At least 55 records · Page 3Linked to original sources
PubMed2004

SARS among critical care nurses, Toronto.

To determine factors that predispose or protect healthcare workers from severe acute respiratory syndrome (SARS), we conducted a retrospective cohort study among 43 nurses who worked in two Toronto critical care units with SARS patients. Eight of 32 nurses who entered a SARS patient's room were infected. The probability of SARS infection was 6% per shift worked. Assisting during intubation, suctioning before intubation, and manipulating the oxygen mask were high-risk activities. Consistently wearing a mask (either surgical or particulate respirator type N95) while caring for a SARS patient was protective for the nurses, and consistent use of the N95 mask was more protective than not wearing a mask. Risk was reduced by consistent use of a surgical mask, but not significantly. Risk was lower with consistent use of a N95 mask than with consistent use of a surgical mask. We conclude that activities related to intubation increase SARS risk and use of a mask (particularly a N95 mask) is protective.

Cohort Studies↗
PubMed2004

Clinical trials and novel pathogens: lessons learned from SARS.

During the recent global outbreak of severe acute respiratory syndrome (SARS), thousands of patients received treatments of uncertain efficacy and known toxicity such as ribavirin and corticosteroids. Despite this, no controlled clinical trials assessing the efficacy of these agents were conducted. If a second global SARS outbreak occurred, clinicians would not have controlled data on which to base therapeutic decisions. We discuss the unique methodologic and logistical challenges faced by researchers who attempt to conduct controlled trials of therapeutic agents during an outbreak of a novel or unknown infectious pathogen. We draw upon our own experience in attempting to conduct a randomized controlled trial (trial) of ribavirin therapy for SARS and discuss the lessons learned. Strategies to facilitate future clinical trials during outbreaks of unknown or novel pathogens are also presented.

Antiviral Agents↗
PubMed2004

Hospital preparedness and SARS.

On May 23, 2003, Toronto experienced the second phase of a severe acute respiratory syndrome (SARS) outbreak. Ninety cases were confirmed, and >620 potential cases were managed. More than 9,000 persons had contact with confirmed or potential case-patients; many required quarantine. The main hospital involved during the second outbreak was North York General Hospital. We review this hospital's response to, and management of, this outbreak, including such factors as building preparation and engineering, personnel, departmental workload, policies and documentation, infection control, personal protective equipment, training and education, public health, management and administration, follow-up of SARS patients, and psychological and psychosocial management and research. We also make recommendations for other institutions to prepare for future outbreaks, regardless of their origin.

Canada↗
PubMed2004

SARS in healthcare facilities, Toronto and Taiwan.

The healthcare setting was important in the early spread of severe acute respiratory syndrome (SARS) in both Toronto and Taiwan. Healthcare workers, patients, and visitors were at increased risk for infection. Nonetheless, the ability of individual SARS patients to transmit disease was quite variable. Unrecognized SARS case-patients were a primary source of transmission, and early detection and intervention were important to limit spread. Strict adherence to infection control precautions was essential in containing outbreaks. In addition, grouping patients into cohorts and limiting access to SARS patients minimized exposure opportunities. Given the difficulty in implementing several of these measures, control measures were frequently adapted to the acuity of SARS care and level of transmission within facilities. Although these conclusions are based only on a retrospective analysis of events, applying the experiences of Toronto and Taiwan to SARS preparedness planning efforts will likely minimize future transmission within healthcare facilities.

Canada↗
PubMed2004

Nursing home residents and Enterobacteriaceae resistant to third-generation cephalosporins.

Limited data identify the risk factors for infection with Enterobacteriaceae resistant to third-generation cephalosporins among residents of long-term-care facilities. Using a nested case-control study design, nursing home residents with clinical isolates of Enterobacteriaceae resistant to third-generation cephalosporins were compared to residents with isolates of Enterobacteriaceae susceptible to third-generation cephalosporins. Data were collected on antimicrobial drug exposure 10 weeks before detection of the isolates, facility-level demographics, hygiene facilities, and staffing levels. Logistic regression models were built to adjust for confounding variables. Twenty-seven case-residents were identified and compared to 85 controls. Exposure to any cephalosporin (adjusted odds ratio [OR] 4.0, 95% confidence interval [CI] 1.2 to 13.6) and log percentage of residents using gastrostomy tubes within the nursing home (adjusted OR 3.9, 95% CI 1.3 to 12.0) were associated with having a clinical isolate resistant to third-generation cephalosporins.

Aged↗
PubMed2003

Investigation of a nosocomial outbreak of severe acute respiratory syndrome (SARS) in Toronto, Canada.

BACKGROUND: Severe acute respiratory syndrome (SARS) was introduced into Canada by a visitor to Hong Kong who returned to Toronto on Feb. 23, 2003. Transmission to a family member who was later admitted to a community hospital in Toronto led to a large nosocomial outbreak. In this report we summarize the preliminary results of the epidemiological investigation into the transmission of SARS between 128 cases associated with this hospital outbreak. METHODS: We collected epidemiologic data on 128 probable and suspect cases of SARS associated with the hospital outbreak, including those who became infected in hospital and the next generation of illness arising among their contacts. Incubation periods were calculated based on cases with a single known exposure. Transmission chains from the index family to hospital contacts and within the hospital were mapped. Attack rates were calculated for nurses in 3 hospital wards where transmission occurred. RESULTS: The cases ranged in age from 21 months to 86 years; 60.2% were female. Seventeen deaths were reported (case-fatality rate 13.3%). Of the identified cases, 36.7% were hospital staff. Other cases were household or social contacts of SARS cases (29.6%), hospital patients (14.1%), visitors (14.1%) or other health care workers (5.5%). Of the 128 cases, 120 (93.8%) had documented contact with a SARS case or with a ward where there was a known SARS case. The remaining 8 cases without documented exposure are believed to have had exposure to an unidentified case and remain under investigation. The attack rates among nurses who worked in the emergency department, intensive care unit and coronary care unit ranged from 10.3% to 60.0%. Based on 42 of the 128 cases with a single known contact with a SARS case, the mean incubation period was 5 days (range 2 to 10 days). INTERPRETATION: Evidence to date suggests that SARS is a severe respiratory illness spread mainly by respiratory droplets. There has been no evidence of further transmission within the hospital after the elapse of 2 full incubation periods (20 days).

Adolescent↗
PubMed2003

Risk factors for early-onset group B streptococcal disease in neonates: a population-based case-control study.

BACKGROUND: Infection with group B streptococcus (GBS) is a major cause of neonatal illness and death. We examined the antenatal and perinatal risk factors for early-onset GBS disease among neonates. METHODS: We identified cases by population-based surveillance in all microbiology laboratories serving Alberta. A case was defined as any instance of a positive sterile-site GBS culture in an infant born between 1993 and 1997 who was either less than 7 days old or stillborn after 20 weeks' gestation. We randomly selected controls from a computer-compiled list of all hospital births, including stillbirths after 20 weeks' gestation, in Alberta during the study period. To increase power, we chose 5 or 6 control infants born in the same year as each case infant. We reviewed hospital, prenatal clinic and physician health records and, between 1997 and 1999, conducted maternal interviews by telephone. RESULTS: There were no differences between the 90 cases and 489 controls in sociodemographic variables or in many reproductive and behavioural variables. Case infants were more likely than control infants to be of low birth weight (odds ratio [OR] 3.60, 95% confidence interval [CI] 1.68-7.65), to have been delivered preterm (OR 3.89, 95% CI 2.08-7.27), or to have a mother with amnionitis (OR 15.03, 95% CI 5.58-41.89), intrapartum fever (OR 4.65, 95% CI 2.48-8.69) or premature rupture of the membranes (OR 2.39, 95% CI 1.38-4.14). After adjustment for potential confounders, intrauterine fetal monitoring was associated with a more than 2-fold increase in the risk of neonatal GBS disease (OR 2.24, 95% CI 1.22-4.13). INTERPRETATION: Intrauterine fetal monitoring should be added to the list of risk factors in risk-based screening. Since many of the cases had no identifiable maternal risk factors, universal screening for GBS may be appropriate.

Alberta↗
PubMed2003

West Nile virus infection in 2002: morbidity and mortality among patients admitted to hospital in southcentral Ontario.

BACKGROUND: In August and September 2002 an outbreak of West Nile virus (WNV) infection occurred in southern Ontario. We encountered a number of seriously ill patients at our hospitals. In this article we document the clinical characteristics of these cases. METHODS: We conducted a retrospective chart review of patients who came to the attention of infectious disease or neurology consultants or the microbiology laboratories at 7 hospitals in the municipalities of Toronto, Peel and Halton, Ont. Patients were included if they had been admitted to hospital or stayed overnight in the emergency department, had serological evidence of WNV infection and had clinical evidence of WNV fever, aseptic meningitis, encephalomyelitis or motor neuronopathy. RESULTS: In all, 64 patients met the inclusion criteria; 57 had encephalitis or neuromuscular weakness or both, 5 had aseptic meningitis, and 2 had WNV fever. The mean age was 61 years (range 26-87). The patients were predominantly active, middle-aged or elderly people living independently in the community. Seven patients were immunocompromised A febrile prodromal illness preceded the neurological symptoms in almost all cases. The most common neurological abnormality was decreased level of consciousness; this frequently evolved to severe lower motor neuron neuromuscular weakness. Ataxia and swallowing disorders were frequent and important problems. Sixteen patients (25%) required intubation and mechanical ventilation because of a decreased level of consciousness, inability to clear secretions or respiratory muscle weakness; 9 others had disabling muscle weakness of one or more limbs. Ten patients died. The study patients were in hospital a total of 1856 patient-days, including 532 patient-days in an intensive care unit. Only 28% (13/47) of the patients who survived encephalitis or neuromuscular weakness, or both, were discharged home without additional support. Slow turnaround time for serological test results resulted in delayed diagnosis. INTERPRETATION: The 2002 WNV infection outbreak in Ontario caused serious morbidity and mortality in the subset of patients who had encephalitis or neuromuscular weakness severe enough to require hospital admission.

Adult↗
PubMed2003

Clinical and epidemiologic features of group a streptococcal pneumonia in Ontario, Canada.

BACKGROUND: Since the 1960s, group A streptococcus (GAS) has accounted for less than 1% of cases of community-acquired pneumonia. During the past 2 decades there has been a resurgence of invasive GAS infection, but no large study of GAS pneumonia has been performed. METHODS: To determine the clinical and epidemiologic features of GAS pneumonia, we conducted prospective, population-based surveillance of all invasive GAS infection in residents of Ontario from January 1, 1992, through December 31, 1999. RESULTS: Of 2079 cases of invasive GAS infection, 222 (11%) represented GAS pneumonia. The incidence of GAS pneumonia ranged from 0.16 per 100 000 in 1992 to 0.35 per 100 000 in 1999. Most cases were community acquired (81%). Forty-four percent of nursing home-acquired cases occurred during outbreaks. The case fatality rate was 38% for GAS pneumonia, compared with 12% for the entire cohort with invasive GAS infection and 26% for patients with necrotizing fasciitis. The presence of streptococcal toxic shock syndrome (odds ratio, 19; 95% confidence interval, 8.4-42; P =.001) and increasing age (odds ratio per decade, 1.45; 95% confidence interval, 1.2-1.7; P<.001) were associated with fatal outcome. Time to death was rapid, with a median of 2 days despite antimicrobial therapy and supportive measures. CONCLUSIONS: Group A streptococcal pneumonia is a common form of invasive GAS disease but remains an uncommon cause of community-acquired pneumonia. Progression is rapid despite appropriate therapy. The incidence is similar to, and the case fatality rate higher than, that of necrotizing fasciitis.

Chi-Square Distribution↗
PubMed2003

Clinical manifestations associated with the aberrant expression of the soluble granulocyte-macrophage colony-stimulating factor receptor in patients presenting with haematological malignancies.

The receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) can exist as both transmembrane (tmGMRalpha) and soluble (solGMRalpha) isoforms, and the latter, is a normal constituent of human plasma. We investigated if aberrant solGMRalpha expression occurs in haematopoietic malignancies and whether or not solGMRalpha expression levels correlated with clinical presentation. Compared with the normal population, patients with acute lymphoblastic leukaemia (ALL) had low levels of solGMRalpha whereas clonal disorders of the myeloid lineage demonstrated higher levels of solGMRalpha. Patients with acute myelogenous leukaemia (AML) and high levels of solGMRalpha presented with a distinct clinical picture. These patients were older, predominantly belonged to the M4 and M5 French-American-British (FAB) subtypes, and they had higher white blood cell counts at presentation including myeloid precursors and myeloblasts. They often presented with either unexplained lung infiltrates or hypoxia and lower rates of microbiologically defined infections. Elevated solGMRalpha levels were not associated with decreased relapse-free and overall survival in the AML population. On multivariate analysis, the correlation between elevated solGMRalpha levels and age, M4 and M5 FAB subtypes and decreased numbers of infections persisted. Our study is the first to describe that distinct clinical presentations are associated with aberrant solGMRalpha levels in haematological malignancies.

Adolescent↗
PubMed2003

Use of, effectiveness of, and attitudes regarding influenza vaccine among house staff.

OBJECTIVE: To determine influenza vaccination rates, vaccine effectiveness, and factors influencing vaccination decisions among house staff. DESIGN: Cross-sectional survey. SETTING AND PARTICIPANTS: All residents registered at the University of Toronto were surveyed after the 1999-2000 influenza season. Of the 1,159 questionnaires mailed, 670 (58%) could be evaluated. RESULTS: Influenza-like illnesses were reported by 36% of house staff. The vaccination rate was 51% among respondents, being highest for community and occupational medicine and pediatric staff (77% and 75%) and lowest for psychiatry, surgery, and radiology staff (32%, 36%, and 36%). Vaccinees reported significantly fewer episodes of illness (42 vs 54 per 100 subjects; P = .03) and fewer days of illness (272 vs 374 per 100 subjects; P = .02); absenteeism was not different (63 vs 69 per 100 subjects; P = .69). Self-protection was the most common reason for vaccination. Vaccinees believed the vaccine was more effective than did non-vaccinees (P < .01). Non-vaccinees considered influenza-like symptoms the most important side effect of the vaccine. Busy schedules and inconvenience were the most common reasons for not getting vaccinated. Overall, 44% of house staff believed the influenza vaccine should be mandatory. CONCLUSIONS: Influenza-like illness was common among house staff. They tended to work through their illnesses, potentially putting patients at risk. They were motivated mostly by self-protection and did report a benefit. Despite busy schedules and an unfounded fear of getting influenza symptoms from the vaccine, many thought the vaccine should be mandatory.

Absenteeism↗
PubMed2003

Antimicrobial susceptibility breakpoints and first-step parC mutations in Streptococcus pneumoniae: redefining fluoroquinolone resistance.

Clinical antimicrobial susceptibility breakpoints are used to predict the clinical outcome of antimicrobial treatment. In contrast, microbiologic breakpoints are used to identify isolates that may be categorized as susceptible when applying clinical breakpoints but harbor resistance mechanisms that result in their reduced susceptibility to the agent being tested. Currently, the National Committee for Clinical Laboratory Standards (NCCLS) guidelines utilize clinical breakpoints to characterize the activity of the fluoroquinolones against Streptococcus pneumoniae. To determine whether levofloxacin breakpoints can identify isolates that harbor recognized resistance mechanisms, we examined 115 S. pneumoniae isolates with a levofloxacin MIC of >2 mg/mL for first-step parC mutations. A total of 48 (59%) of 82 isolates with a levofloxacin MIC of 2 mg/mL, a level considered susceptible by NCCLS criteria, had a first-step mutation in parC. Whether surveillance programs that use levofloxacin data can effectively detect emerging resistance and whether fluoroquinolones can effectively treat infections caused by such isolates should be evaluated.

Anti-Infective Agents↗
PubMed2003

Invasive group A streptococcal disease: risk factors for adults.

We conducted a case-control study to identify risk factors for invasive group A streptococcal (GAS) infections, which can be fatal. Case-patients were identified when Streptococcus pyogenes was isolated from a normally sterile site and control subjects (two or more) were identified and matched to case-patients by using sequential-digit telephone dialing. All participants were noninstitutionalized surveillance area residents, >18 years of age. Conditional logistic regression identified the risk factors for invasive GAS infection: in adults 18 to 44 years of age, exposure to one or more children with sore throats (relative risk [RR]=4.93, p=0.02), HIV infection (RR=15.01, p=0.04), and history of injecting drug use (RR=14.71, p=0.003); in adults >45 years of age, number of persons in the home (RR=2.68, p=0.004), diabetes (RR=2.27, p=0.03), cardiac disease (RR=3.24, p=0.006), cancer (RR=3.54, p=0.006), and corticosteroid use (RR=5.18, p=0.03). Thus, host and environmental factors increased the risk for invasive GAS disease.

Adult↗
PubMed2002

An immunogenetic and molecular basis for differences in outcomes of invasive group A streptococcal infections.

The role of host genetic factors in conferring predisposition or protection in infectious diseases has become evident. Infection with group A streptococci causes a wide spectrum of disease ranging from pharyngitis to streptococcal toxic shock syndrome. The release of inflammatory cytokines triggered by streptococcal superantigens has a pivotal role in invasive streptococcal disease. However, individuals infected with the same strain can develop very different manifestations. We report here that the immunogenetics of the host influence the outcome of invasive streptococcal infection, and demonstrate the underlying mechanism for these genetic associations. Specific human leukocyte antigen class II haplotypes conferred strong protection from severe systemic disease, whereas others increased the risk of severe disease. Patients with the DRB1*1501/DQB1*0602 haplotype mounted significantly reduced responses and were less likely to develop severe systemic disease (P < 0.0001). We propose that human leukocyte antigen class II allelic variation contributes to differences in severity of invasive streptococcal infections through their ability to regulate cytokine responses triggered by streptococcal superantigens.

Fasciitis, Necrotizing↗
PubMed2002

Optimizing antibiotics in residents of nursing homes: protocol of a randomized trial.

BACKGROUND: Antibiotics are frequently prescribed for older adults who reside in long-term care facilities. A substantial proportion of antibiotic use in this setting is inappropriate. Antibiotics are often prescribed for asymptomatic bacteriuria, a condition for which randomized trials of antibiotic therapy indicate no benefit and in fact harm. This proposal describes a randomized trial of diagnostic and therapeutic algorithms to reduce the use of antibiotics in residents of long-term care facilities. METHODS: In this on-going study, 22 nursing homes have been randomized to either use of algorithms (11 nursing homes) or to usual practise (11 nursing homes). The algorithms describe signs and symptoms for which it would be appropriate to send urine cultures or to prescribe antibiotics. The algorithms are introduced by inservicing nursing staff and by conducting one-on-one sessions for physicians using case-scenarios. The primary outcome of the study is courses of antibiotics per 1000 resident days. Secondary outcomes include urine cultures sent and antibiotic courses for urinary indications. Focus groups and semi-structured interviews with key informants will be used to assess the process of implementation and to identify key factors for sustainability.

Aged↗