Biomedical subjects

Daniel R Feikin

Publications and source records attributed to Daniel R Feikin.

At least 19 recordsLinked to original sources

PubMed2006

Seropositivity to Chlamydia pneumoniae is associated with risk of first ischemic stroke.

BACKGROUND AND PURPOSE: Serologic evidence of infection with Chlamydia pneumoniae has been associated with cardiovascular disease, but its relationship with stroke risk remains uncertain. The objective of this study is to determine whether serological evidence of C pneumoniae infection is associated with risk of ischemic stroke. METHODS: A population-based case-control study was performed in an urban, multiethnic population. Cases (n=246) had first ischemic stroke, and controls (n=474) matched for age, sex, and race-ethnicity were derived through random-digit dialing. Titers of C pneumoniae-specific IgG and IgA antibodies were measured using microimmunofluorescence, and positive titers were prospectively defined. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% CIs adjusting for medical, behavioral, and socioeconomic factors. RESULTS: Mean age among cases was 72.3+/-9.7 years; 50.8% were women. Elevated C pneumoniae IgA titers were associated with increased risk of ischemic stroke after adjusting for hypertension, diabetes mellitus, current cigarette use, atrial fibrillation, and levels of high-density lipoprotein and low-density lipoprotein (adjusted OR, 1.5; 95% CI, 1.0 to 2.2). Elevated IgG titers were not associated with stroke risk (adjusted OR, 1.2; 95% CI, 0.8 to 1.8). There was a trend toward an association of elevated IgA titers with atherosclerotic and lacunar stroke but less so cardioembolic or cryptogenic subtypes. CONCLUSIONS: Serologic evidence of C pneumoniae infection is associated with ischemic stroke risk. IgA titers may be a better marker of risk than IgG. This association is independent of other stroke risk factors and is present for atherosclerotic, lacunar, and cardioembolic subtypes. Further studies of the effect of C pneumoniae on stroke risk are warranted.

Aged↗

PubMed2006

Serotypes and antimicrobial resistance of streptococcus pneumoniae in Thailand 2002-2004.

Information on pneumococcal isolates is limited in Asia. Among children younger than 5 years in rural Thailand, nasopharyngeal colonization was 60%, and 55% of carried and 62% of invasive isolates were serotypes in the 7-valent pneumococcal conjugate vaccine. Nonsusceptibility was common among the serotypes included in the vaccine. Pneumococcal conjugate vaccine might be a useful prevention tool in Thailand.

Adolescent↗

PubMed2006

Two outbreaks of severe respiratory disease in nursing homes associated with rhinovirus.

OBJECTIVES: To characterize illness and identify the etiology for two nursing home outbreaks of respiratory illness. DESIGN: Multisite outbreak investigations; cohort. SETTING: Two nursing homes in Pennsylvania. PARTICIPANTS: Facility A residents (n = 170), Facility B residents (n = 124), and employees (n = 91). MEASUREMENTS: Medical records for Facility A and B residents were reviewed, and employees from Facility B self-administered a questionnaire to identify risk factors for illness. Serological, oropharyngeal, and nasopharyngeal specimens were collected for both outbreaks, and testing for respiratory pathogens was performed. RESULTS: In Facility A, 40 (24%) of 170 residents were identified with respiratory illness; 13 (33%) case-patients had radiographically confirmed pneumonia, 15 (38%) were taken to a hospital, and two (5%) died. Of 10 specimens collected from symptomatic Facility A case-patients, four (40%) tested positive using reverse transcription polymerase chain reaction for rhinovirus. In Facility B, 77 (62%) of 124 residents had respiratory illness, and 40 (52%) had radiographically confirmed pneumonia; 12 (16%) case-patients were hospitalized, and five (6%) died. Of 19 respiratory specimens collected from symptomatic Facility B case-patients, six (32%) were positive for rhinovirus; one was from an employee. Five (50%) of 10 rhinovirus-positive cases in both outbreaks had clinical and radiographic evidence of pneumonia. CONCLUSION: These investigations suggest that rhinoviruses may be an underrecognized cause of respiratory outbreaks in nursing homes, capable of causing pneumonia and perhaps death.

Acute Disease↗

PubMed2005

Could a single dose of pneumococcal conjugate vaccine in children be effective? Modeling the optimal age of vaccination.

Using incidence rates from CDC's Active Bacterial Core surveillance and immunogenicity data from the Navajo/Apache trial of pneumococcal conjugate vaccine (PCV), we used Markov modeling to predict the optimal age to give a single dose of PCV. Antibody concentration thresholds of 0.35 and 1.0 mcg/ml were considered protective. Our outcome was vaccine serotype-specific invasive pneumococcal disease (IPD) incidence at 24 months. The models predicted the optimal age to vaccinate is 5-7 months with vaccine-induced immunologic memory and 8-10 months without memory. IPD reduction ranged from 15 to 62%, depending on model parameters. A single PCV dose in infants could prevent substantial IPD.

Adolescent↗

PubMed2005

Increased prevalence of pediatric pneumococcal serotypes in elderly adults.

BACKGROUND: Pneumococcal disease is most prevalent among young children and elderly adults. We explored whether similarities exist in the serotypes that cause disease in these 2 high-risk groups. METHODS: With use of US population-based data from 1998-1999 (before the introduction of the 7-valent pneumococcal conjugate vaccine [PCV7] as routine immunization for infants) from the Centers for Disease Control and Prevention's Active Bacterial Core surveillance, we evaluated whether the rate of invasive pneumococcal disease caused by the pediatric serotypes (6B, 9V, 14, 19F, and 23F) increased among elderly persons. We adjusted for potential confounders in multivariable logistic regression. RESULTS: We analyzed 2987 pneumococcal isolates recovered from adults. The risk of infection with pediatric serotypes increased from 32.5% in 35-49-year-old persons to 51.2% in > or = 85-year-old persons (P < .001). Compared with 35-49-year-old persons, the risk of infection with pediatric serotypes was significantly elevated among 65-74-year-old persons (relative risk [RR], 1.68; 95% confidence interval [CI], 1.29-2.20) and increased progressively among persons aged 75-84 years (RR, 1.82; 95% CI, 1.41-2.36) and > or = 85 years (RR, 2.29; 95% CI, 1.72-3.05), with adjustment for sex, race, geographic location, underlying illness, and penicillin resistance. The rate of penicillin resistance was also elevated in the elderly population but was not significant after adjustment for serotype and race. CONCLUSIONS: The increased proportion of severe pneumococcal disease caused by pediatric serotypes in the elderly population might indicate opportunities for prevention with use of PCV7.

Adult↗

PubMed2005

Safety of varying dosages of 7-valent pneumococcal protein conjugate vaccine in seniors previously vaccinated with 23-valent pneumococcal polysaccharide vaccine.

In a phase I/II dose escalation study, varying volumes (0.1 ml, 0.5 ml, 1.0 ml and 2.0 ml) of 7-valent pneumococcal conjugate vaccine (PCV) (Prevnar or 0.5 ml of 23-valent pneumococcal polysaccharide vaccine (PPV) were administered to 220 adults 70 through 79 years of age previously vaccinated with 0.5 ml PPV at age 65 years or above and at least 5 years previously. Fever was uncommon and did not vary by study group. The rate of local reactions increased with higher volumes of PCV and the rate following 2.0 ml of PCV was comparable to that following 0.5 ml PPV.

Aged↗

PubMed2005

Recurrence of legionnaires disease at a hotel in the United States Virgin Islands over a 20-year period.

We investigated 3 cases of legionnaires disease (LD) that developed in travelers who stayed at a hotel in the United States Virgin Islands where cases of LD occurred in 1981-1982 and in 1998. The temperature of the potable water at the hotel was in a range that could optimally support the growth of Legionella species, and the potable water was colonized with Legionella pneumophila in 1981-1982 and in 2002-2003.

Humans↗

PubMed2005

Leukocyte count is associated with reduced endothelial reactivity.

BACKGROUND: Leukocyte count has been associated with cardiovascular and cerebrovascular disease in several studies. We hypothesized that white blood cell count is associated with endothelial reactivity. METHODS AND RESULTS: Leukocyte count was measured in a sample of stroke-free community participants undergoing brachial artery testing for endothelial reactivity. Flow-mediated dilation (FMD) during reactive hyperemia was assessed in each subject using high-resolution B-mode ultrasound. Multivariate linear regression was used to calculate the effect of leukocyte count on endothelial reactivity after adjusting for potential confounding factors. Mean age of the 868 participants was 66.7+/-8.8 years; 57% were women. Mean leukocyte count was (6.1+/-1.8)x10(9)/L. Each unit increase in leukocyte count was associated with a mean 0.18% decrease in FMD (p = 0.01). After adjusting for other atherosclerosis risk factors, including age, sex, hypertension, diabetes, hyperlipidemia, and smoking, the relationship persisted (mean decrease in FMD per unit leukocyte count = 0.17%, p = 0.02). There was a linear decrease in FMD by quartile of leukocyte count (p = 0.0014). The effect of leukocyte count on FMD was greater for women, those under age 70, and non-diabetics. CONCLUSIONS: Relative elevations in leukocyte count are associated with a reduction in brachial artery endothelial reactivity. These findings are consistent with current hypotheses regarding the inflammatory or infectious etiology of risk of atherosclerosis and stroke, but also suggest interactions with demographic and other risk factors.

Aged↗

PubMed2005

Epidemiological differences among pneumococcal serotypes.

The bacterial species Streptococcus pneumoniae consists of 90 immunologically distinct serotypes, of which some possess distinct epidemiological properties. Certain serotypes are much more likely to be associated with nasopharyngeal colonisation than to cause invasive disease. Compared with transient or infrequent colonisers, serotypes carried at high rates by young children may rapidly elicit age-associated natural immunity to invasive disease. Other serotypes seem to be of disproportionate importance as causes of disease in very young infants, in older children, in immunocompromised individuals, or in elderly people. Some serotypes seem to be associated with particular disease syndromes, such as complicated pneumonias in children, or with higher rates of hospitalisation in children or mortality in adults, or are consistently responsible for outbreaks in certain populations. Since pneumococcal conjugate vaccines are directed at specific serotypes, national immunisation advisory committees may wish to consider these serotype-specific properties when considering which vaccine formulation to introduce into a national programme.

Humans↗

PubMed2005

Novel antibiotic-resistant pneumococcal strains recovered from the upper respiratory tracts of HIV-infected adults and their children in Kisumu, Kenya.

In a survey of genetic diversity within penicillin-nonsusceptible pneumococcal isolates in Kenya, we examined 162 upper respiratory isolates from 104 human immunodeficiency virus (HIV)-infected adults and 46 children in a cotrimoxazole prophylaxis study. Antibiotic resistance levels were high; 152 (94.4%) were cotrimoxazole nonsusceptible (134 fully resistant) and 124 (77%) were intermediately penicillin resistant. Isolates nonsusceptible to penicillin and cotrimoxazole (PNCNP) were found among 24 of the 29 serotypes encountered, 15 of which have rarely or never had documented nonsusceptibility to penicillin. These included serotypes 3, 4, 7C, 7F, 10A, 11A, 13, 15A, 15B, 16F, 17F, 19B, 21, 35A, and 35B. Segments of pbp2b genes from 9 PNCNP (serotypes 3, 13, 15A, 16F, 20, and 35A) were typical of resistance-conferring alleles in that they were highly divergent and contained two substitutions thought to be critical for resistance. Similarly, the dhfr genes from 3 PNCNP were divergent and contained a substitution required for cotrimoxazole resistance. Multilocus sequence typing (MLST) of 48 PNCNP revealed 33 sequence types (STs), none of which were previously recorded at http://www.mlst.net. Comparisons with all known STs revealed that 23 of these STs were unrelated to other known STs, whereas 10 STs were highly related to STs from internationally disseminated strains, including 2 of the 26 antibiotic-resistant clones recognized by the Pneumococcal Molecular Epidemiology Network. Based upon differing serotypes expressed by strains of identical or closely similar genotypes, there has been an extensive history of capsular switching within seven genetic clusters represented by these 10 STs and related STs described at http://www.mlst.net.

Adult↗

PubMed2004

Global strategies to prevent bacterial pneumonia in adults with HIV disease.

We examined the peer-reviewed literature on the burden of bacterial pneumonia and the effectiveness of interventions for its prevention among HIV-infected adults in developed and developing countries. Bacterial pneumonia rates were up to 25-fold higher among HIV-infected adults than in the general community, with rates increasing as CD4+ T-cell count decreases. In developed countries, cohort studies showed that highly active antiretroviral therapy (HAART) had the most consistent effect on reducing pneumonia. In a prospective cohort and case-control studies from these regions, pneumococcal polysaccharide vaccine reduced pneumococcal disease in certain subgroups, particularly those with higher CD4+ T cells/microL. In patients with fewer than 200 CD4+ T cells/microL, antimicrobial prophylaxis was usually effective in reducing pneumonia. In sub-Saharan Africa, randomised controlled trials concluded that co-trimoxazole prophylaxis decreased rates of bacterial pneumonia, but pneumococcal polysaccharide vaccine prevented neither pneumonia nor invasive pneumococcal disease. Although not yet fully evaluated in Africa, based on experience in industrialised nations, use of HAART in Africa may have substantial potential to prevent bacterial pneumonia.

AIDS-Related Opportunistic Infections↗

PubMed2004

Impact of haemophilus influenzae type b conjugate vaccine in South Africa and Argentina.

INTRODUCTION: Haemophilus influenzae type b (Hib) persists as a major cause of pediatric meningitis and pneumonia in developing countries in which Hib conjugate vaccines are not used. Demonstration of decreases in severe Hib disease after countries introduce Hib conjugate vaccine will help justify the resources necessary to purchase and provide the vaccine. Because surveillance for culture-confirmed Hib meningitis is not available in many countries, alternative means to measure the impact of Hib conjugate vaccine would be useful. METHODS: Laboratory records from the years before and after introduction of the Hib conjugate vaccine were reviewed at 4 hospitals, 2 in Argentina and 2 in South Africa. Potential indicators of bacterial meningitis including cerebrospinal fluid (CSF) culture, white blood cell count, appearance, protein and glucose were recorded. RESULTS: After introduction of Hib conjugate vaccine, culture-confirmed Hib meningitis declined significantly at 3 of 4 hospitals (2 in Argentina and 1 in South Africa). In the same 3 hospitals, there was a significant decline after vaccine introduction in some of the following CSF indicators of bacterial meningitis: proportion of CSF specimens with white blood cell count > or = 100 x 10(6)/L, 500 x 10(6)/L and 1,000 x 10(6)/L; glucose <40 mg/dL; protein >100 mg/dL; and turbid appearance. CONCLUSIONS: Culture-confirmed Hib meningitis declined at 3 of the 4 hospitals after Hib vaccine introduction. Surrogate indicators of bacterial meningitis also declined and might be useful measures of Hib conjugate vaccine impact at hospitals where capacity to culture Hib is not available.

Age Distribution↗

PubMed2004

Specificity of the antibody response to the pneumococcal polysaccharide and conjugate vaccines in human immunodeficiency virus-infected adults.

Nonspecific antibodies, which are thought to be nonprotective, have been shown to contribute a substantial proportion of the measured concentration in the standardized immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) for pneumococcal polysaccharide capsular antibodies. The presence of such antibodies in human immunodeficiency virus (HIV)-infected persons has not been evaluated. The amount of nonspecific antibodies is proportional to the reduction in IgG antibody concentration that occurs with serum absorption with the heterologous polysaccharide 22F. We measured the amount of nonspecific antibodies before and after vaccination with the pneumococcal conjugate vaccine (PCV; n = 33) or the pneumococcal polysaccharide vaccine (PPV; n = 34) in HIV-infected adults with CD4 counts of >/== 200 cells/mm3. Blood was drawn before and 2 months after vaccination. For prevaccination sera, we found a substantial amount of nonspecific antibodies for serotypes 4, 6B, 9V, and 23F (23 to 47% of measured IgG concentration), but not for serotype 14. There tended to be proportionately less nonspecific antibodies in postvaccine sera than prevaccine sera for PCV, but not for PPV. Subjects with a low HIV viral load (</= 400 copies/ml) had proportionately more nonspecific antibodies than those with higher viral load before and after both vaccines. After 22F absorption, the geometric mean concentrations of antibodies were significantly higher post-PCV than post-PPV for the high viral load group for all five serotypes, but for no serotypes in the low viral load group. These findings confirm that absorption with a heterologous pneumococcal polysaccharide (e.g., 22F) is necessary to remove nonspecific antibodies in a standardized IgG ELISA for pneumococcal capsular antibodies in HIV-infected adults.

Adult↗

PubMed2004

Risk factors for SARS among persons without known contact with SARS patients, Beijing, China.

Most cases of severe acute respiratory syndrome (SARS) have occurred in close contacts of SARS patients. However, in Beijing, a large proportion of SARS cases occurred in persons without such contact. We conducted a case-control study in Beijing that compared exposures of 94 unlinked, probable SARS patients with those of 281 community-based controls matched for age group and sex. Case-patients were more likely than controls to have chronic medical conditions or to have visited fever clinics (clinics at which possible SARS patients were separated from other patients), eaten outside the home, or taken taxis frequently. The use of masks was strongly protective. Among 31 case-patients for whom convalescent-phase (>21 days) sera were available, 26% had immunoglobulin G to SARS-associated coronavirus. Our finding that clinical SARS was associated with visits to fever clinics supports Beijing's strategy of closing clinics with poor infection-control measures. Our finding that mask use lowered the risk for disease supports the community's use of this strategy.

Adolescent↗

PubMed2004

Lack of SARS transmission and U.S. SARS case-patient.

In early April 2003, severe acute respiratory syndrome (SARS) was diagnosed in a Pennsylvania resident after his exposure to persons with SARS in Toronto, Canada. To identify contacts of the case-patient and evaluate the risk for SARS transmission, a detailed epidemiologic investigation was performed. On the basis of this investigation, 26 persons (17 healthcare workers, 4 household contacts, and 5 others) were identified as having had close contact with this case-patient before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-associated coronavirus (SARS-CoV) infection to any close contact of this patient. This investigation documents that, under certain circumstances, SARS-CoV is not readily transmitted to close contacts, despite ample unprotected exposures. Improving the understanding of risk factors for transmission will help focus public health control measures.

Contact Tracing↗

PubMed2004

Rapid assessment tool for Haemophilus influenzae type b disease in developing countries.

Haemophilus influenzae type b (Hib) still causes a substantial number of deaths among children in developing countries, despite the availability of effective conjugate vaccines. A major obstacle in developing a Hib vaccine has been limited awareness about the impact of Hib disease. A tool was developed to estimate the national rates of Hib meningitis and pneumonia by assessing retrospective local data over 7 to 10 days. Data from 11 countries in Africa, the Middle East, and Asia were studied and showed rates of Hib meningitis from >50 cases per 100,000 children >5 years in Ghana and Uganda to <15 per 100,000 in Iran, Jordan, and Uzbekistan. Results were affected by the quality of available data. The Hib rapid assessment tool can be useful to countries that desire a timely assessment of Hib disease rates.

Africa↗

PubMed2003

Evaluation of control measures implemented in the severe acute respiratory syndrome outbreak in Beijing, 2003.

CONTEXT: Beijing, China, experienced the world's largest outbreak of severe acute respiratory syndrome (SARS) beginning in March 2003, with the outbreak resolving rapidly, within 6 weeks of its peak in late April. Little is known about the control measures implemented during this outbreak. OBJECTIVE: To describe and evaluate the measures undertaken to control the SARS outbreak. DESIGN, SETTING, AND PARTICIPANTS: Data were reviewed from standardized surveillance forms from SARS cases (2521 probable cases) and their close contacts observed in Beijing between March 5, 2003, and May 29, 2003. Procedures implemented by health authorities were investigated through review of official documents and discussions with public health officials. MAIN OUTCOME MEASURES: Timeline of major control measures; number of cases and quarantined close contacts and attack rates, with changes in infection control measures, management, and triage of suspected cases; and time lag between illness onset and hospitalization with information dissemination. RESULTS: Health care worker training in use of personal protective equipment and management of patients with SARS and establishing fever clinics and designated SARS wards in hospitals predated the steepest decline in cases. During the outbreak, 30 178 persons were quarantined. Among 2195 quarantined close contacts in 5 districts, the attack rate was 6.3% (95% confidence interval [CI], 5.3%-7.3%), with a range of 15.4% (95% CI, 11.5%-19.2%) among spouses to 0.36% (95% CI, 0%-0.77%) among work and school contacts. The attack rate among quarantined household members increased with age from 5.0% (95% CI, 0%-10.5%) in children younger than 10 years to 27.6% (95% CI, 18.2%-37.0%) in adults aged 60 to 69 years. Among almost 14 million people screened for fever at the airport, train stations, and roadside checkpoints, only 12 were found to have probable SARS. The national and municipal governments held 13 press conferences about SARS. The time lag between illness onset and hospitalization decreased from a median of 5 to 6 days on or before April 20, 2003, the day the outbreak was announced to the public, to 2 days after April 20 (P<.001). CONCLUSIONS: The rapid resolution of the SARS outbreak was multifactorial, involving improvements in management and triage in hospitals and communities of patients with suspected SARS and the dissemination of information to health care workers and the public.

China↗

PubMed2003

Antibiotic resistance and serotype distribution of Streptococcus pneumoniae colonizing rural Malawian children.

Nasopharyngeal swabs were taken from 906 Malawian children <5 years old visiting rural health clinics. Pneumococcal colonization was high, 84% among all children, and occurred early, 65% of it in children <3 months old. Among pneumococcal isolates 46% were nonsusceptible to trimethoprim-sulfamethoxazole, and 21% were nonsusceptible to penicillin. Trimethoprim-sulfamethoxazole use in the previous month was a risk factor for trimethoprim-sulfamethoxazole and penicillin nonsusceptibility. Forty-three percent of isolates were serotypes included in the 7-valent pneumococcal conjugate vaccine, and 37% were vaccine-related serotypes, particularly 6A and 19A.

Chi-Square Distribution↗