PubMed Health⌕ Search

Biomedical subjects

Mark Loeb

Publications and source records attributed to Mark Loeb.

At least 37 records · Page 2Linked to original sources
PubMed2005

Clinical and epidemiologic features of methicillin-resistant Staphylococcus aureus in elderly hospitalized patients.

We describe characteristics of elderly patients with MRSA identified in 37 Canadian hospitals between 1995 and 2002. Of these inpatients, 6,613 (66%) were older than 65 years. They were more likely than younger patients to have been colonized without infection and to have had MRSA isolated from urine or the perineum. The epidemiology and clinical features of these patients is distinct from that of younger patients.

Adult↗
PubMed2005

Modeling transmission of methicillin-resistant Staphylococcus aureus among patients admitted to a hospital.

OBJECTIVE: To determine the impact of the screening test, nursing workload, handwashing rates, and dependence of handwashing on risk level of patient visit on methicillin-resistant Staphylococcus aureus (MRSA) transmission among hospitalized patients. SETTING: General medical ward. METHODS: Monte Carlo simulation was used to model MRSA transmission (median rate per 1,000 patient-days). Visits by healthcare workers (HCWs) to patients were simulated, and MRSA was assumed to be transmitted among patients via HCWs. RESULTS: The transmission rate was reduced from 0.89 to 0.56 by the combination of increasing the sensitivity of the screening test from 80% to 99% and being able to report results in 1 day instead of 4 days. Reducing the patient-to-nurse ratio from 4.3 in the day and 6.8 at night to 3.8 and 5.7, respectively, reduced the number of nosocomial infections from 0.89 to 0.85; reducing the ratio to 1 and 1, respectively, further reduced the number of nosocomial infections to 0.32. Increases in handwashing rates by 0%, 10%, and 20% for high-risk visits yielded reductions in nosocomial infections similar to those yielded by increases in handwashing rates for all visits (0.89, 0.36, and 0.24, respectively). Screening all patients for MRSA at admission reduced the transmission rate to 0.81 per 1,000 patient-days from 1.37 if no patients were screened. CONCLUSION: Within the ranges of parameters studied, the most effective strategies for reducing the rate of MRSA transmission were increasing the handwashing rates for visits involving contact with skin or bodily fluid and screening patients for MRSA at admission.

Cost-Benefit Analysis↗
PubMed2005

A new paradigm for clinical investigation of infectious syndromes in older adults: assessing functional status as a risk factor and outcome measure.

Adults aged 65 and over comprise the fastest growing segment of the U.S. population, and older adults experience greater morbidity and mortality due to infection than young adults. While this factor is well established, most clinical investigation of infectious diseases in the aged focuses on microbiology, and crude endpoints of clinical success such as cure rates or mortality, but often fails to assess functional status, a critical variable in geriatric care. Functional status can be evaluated as a risk factor for infectious disease or an outcome of interest following specific interventions utilizing well-validated instruments. This paper outlines the currently available data suggesting a link between infection, immunity and impaired functional status in the elderly, summarizes commonly employed instruments used to determine specific aspects of functional status, and provides recommendations for a new paradigm in which clinical trials of older adults include functional assessment.

Activities of Daily Living↗
PubMed2005

Intraindividual variability and the effect of acute illness on immune senescence markers.

OBJECTIVES: To determine the intraindividual variability and effect of acute illness on two markers of immune senescence. DESIGN: Cohort study with repeated measures. SETTING: Clinical research center and emergency department at two academic medical centers. PARTICIPANTS: Seventy-three subjects aged 65 and older enrolled in three groups: chronic underlying conditions but no acute illness, acutely ill with infection (community-acquired pneumonia), and acutely ill without infection. MEASUREMENTS: CD16 density on polymorphonuclear neutrophils (PMNs) and the proportion of CD8+ T cells that express CD28 determined twice in the nonacutely ill group and three times (Days 0, 30, and 60) in the acute illness groups. RESULTS: In the nonacutely ill group, PMN CD16 density demonstrated wide intraindividual variation, but there was a strong correlation for repeated measures of the percentage of CD8+ T cells expressing CD28 (correlation coefficient (r)=0.77, P<.001). Acute illness markedly affected both measures, regardless of whether the illness was due to infection; there was no correlation between measures obtained on Day 0 versus Day 30 for either immune marker. In contrast, a strong correlation existed between Day 30 and Day 60 values, particularly for CD8+/CD28+ percentage (r=0.58-0.86; P=.006 to <.001). CONCLUSION: The percentage of CD8+ T cells that express CD28 is a highly reproducible marker of immune senescence. Although acute illness affects this marker, 30 to 60 days of convalescence appears adequate for it to return to baseline.

Acute Disease↗
PubMed2005

Epidemiology of community- and nursing home-acquired pneumonia in older adults.

Pneumococcus remains the most important cause of community-acquired pneumonia in older adults. Alcoholism, bronchial asthma, immunosuppression, lung disease, heart disease, institutionalization and increasing age are important risk factors. There is a reduced prevalence of nonrespiratory symptoms in this age group. Advanced age and comorbidity are important prognostic factors. Influenza and pneumococcal vaccination remain the key factors for prevention.

Aged↗
PubMed2005

Protective behavior and West Nile virus risk.

We conducted a cross-sectional, household survey in Oakville, Ontario, where an outbreak of West Nile virus (WNV) in 2002 led to an unprecedented number of cases of meningitis and encephalitis. Practicing > or =2 personal protective behavior traits reduced the risk for WNV infection by half.

Adolescent↗
PubMed2004

A new paradigm for clinical investigation of infectious syndromes in older adults: assessment of functional status as a risk factor and outcome measure.

Adults aged >or=65 years comprise the fastest-growing segment of the United States population, and older adults experience greater morbidity and mortality due to infection than do young adults. Although age is well established as a risk factor for infection, most clinical investigations of infectious diseases in older adults focus on microbiology and on crude end points of clinical success, such as cure rates or death; however, they often fail to assess functional status, which is a critical variable in geriatric care. Functional status can be evaluated either as a risk factor for infectious disease or as an outcome of interest after specific interventions using well-validated instruments. This article outlines the currently available data that suggest an association between infection, immunity, and impaired functional status in elderly individuals, summarizes the instruments commonly used to determine specific aspects of functional status, and provides recommendations for a new paradigm in which clinical trials that involve older adults include assessment of functional status.

Activities of Daily Living↗
PubMed2004

Lack of association between vascular dementia and Chlamydia pneumoniae infection: a case-control study.

BACKGROUND: Chronic inflammation appears to play a role in the pathogenesis of vascular dementia. Given the association between Chlamydia pneumoniae and stroke, the possibility exists that previous exposure to C. pneumoniae may play a role in vascular dementia. The objective of this study was to determine if there was an association between serological evidence of C. pneumoniae infection or inflammatory markers with vascular dementia. METHODS: 28 case-patients with vascular dementia at a geriatric clinic and 24 caregiver-controls were tested for C. pneumoniae IgG and IgA antibodies. The association between vascular dementia and C. pneumoniae titres as well as inflammatory markers was estimated by using both conditional logistic regression and stratified logistic regression. RESULTS: When matched cases were compared to controls, there was no significant difference in elevated C. pneumoniae specific IgG antibodies (titre >or= 1:32), odds ratio [OR] 1.3 (95% confidence intervals [CI] 0.3 to 6.0), p = 0.71, or in elevated C. pneumoniae specific IgA antibodies (titre >or= 1:16), OR 2.0 (95%CI 0.5 to 8.0), p = 0.33 indicative of past or persistent C. pneumoniae infection. Similarly, no difference in high IgG or IgA antibody levels (IgG titre >or= 1:512 or IgA titre >or= 1:64) between the two groups, indicative of recent C. pneumoniae infection, was found, OR 0.4 (95%CI 0.1 to 2.1), p = 0.27. For C-reactive protein (CRP), the mean difference between 18 matched pairs (case - control) was - 3.33 mg/L. There was no significant difference between cases and controls when comparing log transformed values, OR 0.03 (95%CI 0.00 to 2.89), p = 0.13 or comparing CRP values above or below the median, OR 0.8 (95%CI 0.2 to 3.4), p = 0.71. For fibrinogen, the mean difference between pairs (case - control) was -0.07 g/L. There was no statistical difference between cases and controls when comparing log transformed values, OR 0.6 (95%CI 0.0 to 31.2), p = 0.79 or between fibrinogen values above and below the median, OR = 0.5 (95%CI 0.1 to 2.0), p = 0.50. CONCLUSION: We found no evidence for a significant association between C. pneumoniae infection, inflammatory markers such as CRP and fibrinogen, and vascular dementia.

Aged↗
PubMed2004

Patients with severe sepsis vary markedly in their ability to generate activated protein C.

Activated protein C (APC) supplementation significantly reduces mortality in patients with severe sepsis, presumably by down-regulating coagulation, inflammation, and apoptosis. In vivo, endogenous APC is generated from protein C (PC) "on demand" in response to elevated thrombin levels. Thrombomodulin and endothelial cell protein C receptor are endothelial receptors required to generate APC endogenously. Since these receptors may be down-regulated in sepsis, we measured plasma markers of APC generation in 32 patients with severe sepsis to determine whether APC generation is impaired and whether markers of APC generation correlate with 28-day mortality. Relative to normals, all patients had elevated F1 + 2 and thrombin-antithrombin complex (TAT) levels (markers of thrombin generation and inhibition, respectively), and 28 of 32 patients had reduced PC levels. In 20 patients, APC levels paralleled elevated F1 + 2 levels, whereas 12 patients had low APC levels despite elevated F1 + 2 levels, suggesting that APC generation is impaired in the latter. No significant differences exist between survivors and nonsurvivors with respect to baseline PC levels, F1 + 2 levels, and APACHE II (acute physiology and chronic health evaluation) scores. Baseline APC levels were higher in survivors (P = .024), and baseline F1 + 2/APC ratios were lower in survivors (P = .047). Larger studies are warranted to establish whether APC generation profiles aid in managing sepsis.

APACHE↗
PubMed2004

Risk factors for enteric perforation in patients with typhoid Fever.

A case-control study was performed using the records of patients hospitalized for typhoid fever at Dicle University Hospital, Diyarbakir, Turkey, between 1994 and 1998. Case patients with enteric perforation were compared with control patients with typhoid fever but no enteric perforation. Risk factors for perforation were determined using logistic regression modeling. Forty case patients who had surgery because of typhoid enteric perforation were compared with 80 control patients. In univariate analyses, male sex (p = 0.01), age (p = 0.01), leukopenia (p = 0.01), inadequate antimicrobial therapy prior to admission (p = 0.01), and short duration of symptoms (p = 0.01) were significantly associated with perforation. In multivariate analysis, male sex (odds ratio (OR) = 4.39, 95% confidence interval (CI): 1.37, 14.09; p = 0.01), leukopenia (OR = 3.88, 95% CI: 1.46, 10.33; p = 0.04), inadequate treatment prior to admission (OR = 4.58, 95% CI: 1.14, 18.35; p = 0.03), and short duration of symptoms (OR = 1.22, 95% CI: 1.10, 1.35; p = 0.001) were significant predictors of perforation. A short duration of symptoms, inadequate antimicrobial therapy, male sex, and leukopenia are independent risk factors for enteric perforation in patients with typhoid fever.

Adolescent↗
PubMed2004

Interpretation of diagnostic laboratory tests for severe acute respiratory syndrome: the Toronto experience.

BACKGROUND: An outbreak of severe acute respiratory syndrome (SARS) began in Canada in February 2003. The initial diagnosis of SARS was based on clinical and epidemiological criteria. During the outbreak, molecular and serologic tests for the SARS-associated coronavirus (SARS-CoV) became available. However, without a "gold standard," it was impossible to determine the usefulness of these tests. We describe how these tests were used during the first phase of the SARS outbreak in Toronto and offer some recommendations that may be useful if SARS returns. METHODS: We examined the results of all diagnostic laboratory tests used in 117 patients admitted to hospitals in Toronto who met the Health Canada criteria for suspect or probable SARS. Focusing on tests for SARS-CoV, we attempted to determine the optimal specimen types and timing of specimen collection. RESULTS: Diagnostic test results for SARS-CoV were available for 110 of the 117 patients. SARS-CoV was detected by means of reverse-transcriptase polymerase chain reaction (RT-PCR) in at least one specimen in 59 (54.1%) of 109 patients. Serologic test results of convalescent samples were positive in 50 (96.2%) of 52 patients for whom paired serum samples were collected during the acute and convalescent phases of the illness. Of the 110 patients, 78 (70.9%) had specimens that tested positive by means of RT-PCR, serologic testing or both methods. The proportion of RT-PCR test results that were positive was similar between patients who met the criteria for suspect SARS (50.8%, 95% confidence interval [CI] 38.4%-63.2%) and those who met the criteria for probable SARS (58.0%, 95% CI 44.2%-70.7%). SARS-CoV was detected in nasopharyngeal swabs in 33 (32.4%) of 102 patients, in stool specimens in 19 (63.3%) of 30 patients, and in specimens from the lower respiratory tract in 10 (58.8%) of 17 patients. INTERPRETATION: These findings suggest that the rapid diagnostic tests in use at the time of the initial outbreak lack sufficient sensitivity to be used clinically to rule out SARS. As tests for SARS-CoV continue to be optimized, evaluation of the clinical presentation and elucidation of a contact history must remain the cornerstone of SARS diagnosis. In patients with SARS, specimens taken from the lower respiratory tract and stool samples test positive by means of RT-PCR more often than do samples taken from other areas.

Adolescent↗
PubMed2004

Performance improvement in the long-term-care setting: building on the foundation of infection control.

Infection control programs were among the first organized efforts to improve the quality of healthcare delivered to patients and are an excellent model for the development of other healthcare performance improvement activities. Whether labeled as infection control, quality improvement, or patient safety, performance improvement initiatives share similar methods and principles. The quality of care in long-term-care facilities (LTCFs) has been scrutinized for years and has received renewed attention with the recent initiation of public reporting of quality measures by Medicare. This article reviews the principles of performance improvement, discusses the importance of employing evidence-based interventions, and emphasizes the value of local performance improvement in LTCFs. Residents of LTCFs remain at high risk for the development of nosocomial infections, and among performance improvement initiatives, infection control is recommended as a high priority for all LTCFs. Fortunately, infection control contains the essential elements for performance improvement, and a successful infection control program can provide the foundation for expanding performance improvement throughout the LTCF. There is still much that needs to be done to determine the best clinical practices for LTCFs, and this should remain a priority for future research. Furthermore, efforts should continue to apply these principles at the local level to ensure that all residents of LTCFs receive the best care possible.

Aged↗
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

Pneumococcal immunization in older adults: implications for the long-term-care setting.

OBJECTIVES: To compare the efficacy of the polysaccharide pneumococcal vaccine in older adults between clinical trial and observational studies and to discuss the implications for long-term-care facilities (LTCFs). DATA SOURCE: A Medline search (to April 2003). STUDY SELECTION: All meta-analyses of randomized and quasi-randomized trials of pneumococcal vaccines with placebo or no treatment were sought. All cohort or case-control studies were sought. DATA SYNTHESIS: Of the 16 individual randomized clinical trials included in the reviews, 8 compared pneumococcal vaccine in individuals 55 years and older individuals. Only one study specifically addressed LTCF residents. Although no significant protective effect of the vaccine in elderly subpopulations was found, on the basis of wide confidence intervals and small subpopulation sample sizes, beneficial effects, particularly for pneumococcal bacteremia, could not be ruled out. Of the individual observational studies, 11 specifically evaluated vaccine efficacy in older adults. Vaccine efficacy was demonstrated in 9 of the 11 studies with no protective effect was shown in 2 studies. CONCLUSION: Although the pooling of clinical trial data does not demonstrate significant efficacy of the pneumococcal polysaccharide vaccine in subgroups of older adults, these subgroup studies lacked power to show significant differences. Observational studies repeatedly demonstrate efficacy in older adults, and the vaccine has been demonstrated to be cost-effective and safe. It is strongly promoted by U.S. and Canadian advisory committees. On the basis of this available evidence, the pneumococcal polysaccharide vaccine should currently be recommended for older adults, especially those who are residents of LTCFs.

Aged↗
PubMed2004

Tuberculosis prevention and control in long-term-care facilities for older adults.

In the United States, older adults comprise 22% of cases of tuberculous disease but only 12% of the population. Most cases of tuberculosis (TB) occur in community dwellers, but attack rates are highest among frail residents of long-term-care facilities. The detection and treatment of latent TB infection and TB disease can pose special challenges in older adults. Rapid recognition of possible disease, diagnosis, and implementation of airborne precautions are essential to prevent spread. It is the intent of this evidence-based guideline to assist healthcare providers in the prevention and control of TB, specifically in skilled nursing facilities for the elderly.

Aged↗
PubMed2004

Facility-level correlates of antimicrobial use in nursing homes.

We assessed the contribution of facility-level variables to antimicrobial use in a cohort of 50 nursing homes and found that antimicrobial use was significantly correlated with the percentage of nursing home residents with feeding tubes, the number of healthcare aides, and the country of origin of the facility.

Anti-Infective Agents↗
PubMed2004

Patterns of handwashing behavior and visits to patients on a general medical ward of healthcare workers.

OBJECTIVE: To obtain accurate data regarding the handwashing behavior and patterns of visits to patients by healthcare workers (HCWs). METHODS: All visits by HCWs to selected patient rooms were recorded for 3 days and 2 nights. Additionally, 5 nurses were observed for 1 day each and 2 nurses were observed for 1 night each. Nurses were observed for their entire shifts and all of their activities were recorded. SETTING: A general medical ward in a tertiary-care hospital. PARTICIPANTS: Convenience samples of HCWs and patients. RESULTS: Patients were visited every 25 minutes on average. Monitoring rooms and observing nurses resulted in similar rates of patient visits. The highest level of risk was contact with body fluids in 11% of visits and skin in 40% of visits. The overall rate of handwashing was 46%; however, the rate was higher for visits involving contact with body fluids (81%) and skin (61%). Nurses returned immediately to the same patient 45% of the time. The rate of handwashing was higher for the last of a series of visits to a patient's room (53% vs 30%, P < .0001). CONCLUSIONS: Nurses adjusted their handwashing rates in accordance with the risk level of each visit. Monitoring patient rooms and observing nurses yielded similar estimates of patient visits and proportions of visits involving contact with skin or body fluids. Education programs about hand hygiene may be more effective if patterns of care and levels of risk are incorporated into recommendations.

Body Fluids↗