Search PubMed⌕ Search

Biomedical subjects

J D Kellner

Publications and source records attributed to J D Kellner.

At least 19 recordsLinked to original sources
PubMed2001

Drug-resistant Streptococcus pneumoniae infections: clinical importance, drug treatment, and prevention.

Drug-resistant Streptococcus pneumoniae (DRSP) have complicated the management of pneumococcal infections throughout the world in recent years. Important risk factors for the development of a DRSP infection include recent antibiotic use, young age, immunosuppression, daycare center attendance, and recent hospitalizations. Although intermediate resistance to beta-lactam antibodies does not appear to have an impact on the mortality of S. pneumoniae infections, evidence is accumulating to suggest that more highly resistant isolates may increase mortality. Clinical and bacteriologic failures are more common in DRSP meningitis and otitis media. To select appropriate therapy, one must consider whether a patient has risk factors for resistance, the site and severity of the infection, and antibiotic susceptibility data. Reducing the impact of DRSP may be achieved through reducing antibiotic use in communities and increased understanding of other factors that contribute to the development and transmission of resistance. The most important way to reduce all S. pneumoniae infections is to increase the use of existing polysaccharide vaccines and to begin to use new polysaccharide-protein conjugate vaccines in young children.

Age Factors↗
PubMed2000

Bronchodilators for bronchiolitis.

OBJECTIVES: Bronchiolitis is an acute, highly communicable lower respiratory tract infection. Bronchodilators are commonly used in the management of bronchiolitis in North America, but not in the United Kingdom. The objective of this review was to assess the effects of bronchodilators for bronchiolitis. SEARCH STRATEGY: We searched MEDLINE, EMBASE, Reference Update, reference lists of articles, and the files of two of the authors up to June 1998. SELECTION CRITERIA: Randomised trials comparing bronchodilators with placebo in the treatment of bronchiolitis. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Unpublished data were requested from authors when necessary. MAIN RESULTS: In eight trials with 394 children, 46% demonstrated an improved clinical score with bronchodilators compared to 75% with placebo (odds ratio for no improvement 0.29, 95% confidence interval 0.19 to 0.45). However, the inclusion of studies that enrolled people with recurrent wheezes may have biased these results in favour of bronchodilators. Bronchodilator recipients did not show improvement in measures of oxygenation, the rate of hospitalisation (18% versus 26%, odds ratio 0.70, 95% confidence interval 0.36 to 1.35) or duration of hospitalisation (weighted mean difference 0.12, 95% confidence interval -0.3 to 0.5). REVIEWER'S CONCLUSIONS: Bronchodilators produce modest short-term improvement in clinical scores. This small benefit must be weighed against the costs of these agents.

Bronchiolitis↗
PubMed2000

Glucocorticoids for croup.

BACKGROUND: Since the last meta-analysis in 1989, a number of randomised trials on the benefit of glucocorticoids have been published, resulting in an increasing interest in the use of glucocorticoids to treat outpatients with croup. The objective of this review was to provide evidence to guide clinicians in their treatment of patients with croup, to examine the effectiveness of glucocorticoids in these patients, and to identify areas of uncertainty for future research. OBJECTIVES: To determine the effect of glucocorticoids for children with croup. SEARCH STRATEGY: We searched The Cochrane Controlled Trials Register, MEDLINE (January 1966 to August 1997) and Excerpta Medica/EMBASE (January 1974 to August 1997). We also contacted (by mail) authors of identified croup trials published in the last five years to inquire about other trials, published or unpublished. SELECTION CRITERIA: Meta-analysis of randomised controlled trials that examine the effectiveness of glucocorticoid treatment in children with croup. DATA COLLECTION AND ANALYSIS: Data were extracted using a structured form, which captured patient status (inpatient or outpatient), intervention and control, with the name of the drug, route of administration and dose. Data were also collected on the primary outcome measures comprised of a clinical croup score at baseline (as well as any other subsequent assessment times), length of stay (hours), patients status improved (yes/no), and use of co-interventions. The quality of the trials was assessed using empirically derived items that involved scales and components. Two researchers (TPK, MA) then selected studies as being potentially relevant based on a review of the titles and abstracts, if available. The complete text of these studies was then retrieved. All studies that had been retrieved were reviewed independently by two reviewers (AS, TPK). Data were extracted by one reviewer (MA) and checked for accuracy by a second reviewer (TPK). Two observers independently assessed quality (MA, JK), and inter rater agreement was measured by the intra class correlation. Differences were resolved by consensus. MAIN RESULTS: Twenty-four studies were deemed relevant for inclusion (N=2221). Glucocorticoid treatment was associated with an improvement in the croup severity score at 6 hours with an effect size of -1.0 (95% confidence interval -1.5 to -0.6) and at 12 hours -1.0 (-1.6 to -0. 4); at 24 hours this improvement was no longer significant (-1.0, -2. 0 to 0.1). There was a decrease in the number of adrenaline treatments needed in children treated with glucocorticoids: a decrease of 9% (95% confidence interval 2 to 16%) among those treated with budesonide and of 12% (4 to 20%) among those treated with dexamethasone. There was also a decrease in the length of time spent in accident and emergency (-11 hours, 95% confidence interval -18 to 4 hours), and for inpatients hospital stay was reduced by 16 hours (-31 to 1 hour). Publication bias seems to play a part in these results. REVIEWER'S CONCLUSIONS: Dexamethasone and budesonide are effective in relieving the symptoms of croup as early as 6 hours after treatment. Fewer co-interventions are used and the length of time spent in hospital is decreased in patients treated with glucocorticoids.

Croup↗
PubMed2000

A novel multiresistant Streptococcus pneumoniae serogroup 19 clone from Washington State identified by pulsed-field gel electrophoresis and restriction fragment length patterns.

In 1997, a cluster of multiresistant invasive serogroup 19 pneumococcus infections, including two fatalities, was reported in Washington State. Further investigation identified other cases. Fourteen Washington Streptococcus pneumoniae isolates, four from Alaska, and eight isolates from eastern Canada with reduced penicillin susceptibility (MIC of > or =1 microg/ml) were included in the study. Pulsed-field gel electrophoresis (PFGE) with ApaI, SacII, and SmaI restriction enzymes and IS1167 and mef restriction fragment length polymorphism (RFLP) pattern analysis were performed. Twenty of the 26 isolates had identical or related PFGE patterns, with two or all three enzymes, and identical or related IS1167 RFLP patterns, indicating that they were genetically related. These 20 isolates contained the mef gene conferring erythromycin resistance and had identical mef RFLP patterns. The PFGE and RFLP patterns were distinct from those of six multiresistant clones previously described and suggest that a new multiresistant clone has appeared in Washington, Alaska, and eastern Canada. This newly characterized clone should be included in the Pneumococcal Molecular Epidemiology Network.

Anti-Bacterial Agents↗
PubMed2000

Disseminated bacille Calmette-Guérin infection in an infant with a novel deletion in the interferon-gamma receptor gene.

Six weeks after receiving BCG vaccination, a Canadian aboriginal infant presented with suspected sepsis, lymphadenopathy and hepatosplenomegaly. Lymph node biopsy revealed macrophages filled with acid-fast bacilli. Mycobacterium bovis was cultured from tissue specimens and there was evidence of concomitant cytomegalovirus disease. The infant died of disseminated BCG infection. A novel deletion at nucleotide 165 in the interferon-gamma receptor (IFN-gammaR1) was identified. The incidence of this mutation in the aboriginal population and the impact on the heterozygous state are unknown.

BCG Vaccine↗
PubMed1999

The effectiveness of glucocorticoids in treating croup: meta-analysis.

OBJECTIVE: To determine the effectiveness of glucocorticoid treatment in children with croup. DESIGN: Meta-analysis of randomised controlled trials that examine the effectiveness of glucocorticoid treatment in children with croup. MAIN OUTCOME MEASURES: Score on scale measuring severity of croup, use of cointerventions (adrenaline (epinephrine), antibiotics, or supplemental glucocorticoids), length of stay in accident and emergency or in hospital, and rate of hospitalisation. RESULTS: Twenty four studies met the inclusion criteria. Glucocorticoid treatment was associated with an improvement in the croup severity score at 6 hours with an effect size of -1.0 (95% confidence interval -1.5 to -0.6) and at 12 hours -1.0 (-1.6 to -0.4); at 24 hours this improvement was no longer significant (-1.0, -2.0 to 0.1). There was a decrease in the number of adrenaline treatments needed in children treated with glucocorticoids: a decrease of 9% (95% confidence interval 2% to 16%) among those treated with budesonide and of 12% (4% to 20%) among those treated with dexamethasone. There was also a decrease in the length of time spent in accident and emergency (-11 hours, 95% confidence interval -18 to 4 hours), and for inpatients hospital stay was reduced by 16 hours (-31 to 1 hour). Publication bias seems to play a part in these results. CONCLUSIONS: Dexamethasone and budesonide are effective in relieving the symptoms of croup as early as 6 hours after treatment. Fewer cointerventions are used and the length of time spent in hospital is decreased in patients treated with glucocorticoids.

Anti-Bacterial Agents↗
PubMed1999

Streptococcus pneumoniae carriage in children attending 59 Canadian child care centers. Toronto Child Care Centre Study Group.

OBJECTIVES: To determine the prevalence of Streptococcus pneumoniae nasopharyngeal carriage, antibiotic resistance patterns, and serotypes; to examine the variability of microbiological findings between child care centers; and to determine risk factors for antibiotic resistance. DESIGN: Point prevalence survey. SETTING: Licensed child care centers in Toronto, Ontario. PARTICIPANTS: Healthy children attending the centers. MAIN OUTCOME MEASURES: Prevalence (simple and adjusted for clustering) of carriage, antibiotic resistance, and serotypes; multivariate analysis of risk factors for resistance. RESULTS: Of 1322 children from 59 centers, 586 (44.3%) carried 599 S. pneumoniae isolates. On the day of study, 129 (10.7%) of 1203 children for whom a questionnaire was completed were taking antibiotics and 336 (227.9%) had taken them in the previous month. Decreased susceptibility to penicillin was found in 102 isolates (17.0%) and 82 (13.7%) were resistant to multiple antibiotics. The most common serotypes, in order, were 6B, 23F, 6A, 19F, 14, 11A, and 19A, composing 78% of all isolates. Microbiological results from individual centers were variable, but the overall prevalence of carriage, antibiotic resistance, and serotypes was not significantly different when adjusted for effects of clustering within centers. Multiple logistic regression determined that age younger than 24 months and antibiotic use within the previous month were significant risk factors for carriage of S. pneumoniae resistant to penicillin, sulfamethoxazole-trimethoprim, and erythromycin. CONCLUSIONS: Efforts to reduce antibiotic use in children should be particularly directed toward young children attending child care centers. Studies of infectious diseases in child care centers should consider clustering of pathogens or factors promoting transmission within centers that may result in variability between centers.

Anti-Bacterial Agents↗
PubMed1999

Antibiotic prescribing for Canadian preschool children: evidence of overprescribing for viral respiratory infections.

Antibiotic resistance is associated with prior receipt of antibiotics. An analysis of linked computerized databases for physician visits and antibiotic prescriptions was used to examine antibiotic prescribing for different respiratory infections in preschool children in Canada. In 1995, 64% of 61,165 children aged <5 years made 140,892 visits (mean, 3.6 visits per child) for respiratory infections; 74% of children who made visits received antibiotic prescriptions. Antibiotics were prescribed to 49% of children with upper respiratory tract infection, 18% with nasopharyngitis, 78% with pharyngitis or tonsillitis, 32% with serous otitis media, 80% with acute otitis media, 61% with sinusitis, 44% with acute laryngitis or tracheitis, and 24% with influenza. Acute otitis media accounted for 33% of all visits and 39% of all antibiotic prescriptions. The estimated Canadian-dollar cost of overprescribing was $423,693, or 49% of the total cost of antibiotics ($859,893) used in this group. This population-based study confirms antibiotic overprescribing in Canada.

Anti-Bacterial Agents↗
PubMed1998

The superbugs: evolution, dissemination and fitness.

Since the introduction of antibiotics, bacteria have not only evolved elegant resistance mechanisms to thwart their effect, but have also evolved ways in which to disseminate themselves or their resistance genes to other susceptible bacteria. During the past few years, research has revealed not only how such resistance mechanisms have been able to evolve and to rapidly disseminate, but also how bacteria have, in some cases, been able to adapt to this new burden of resistance with little or no cost to their fitness. Such adaptations make the control of these superbugs all the more difficult.

Anti-Bacterial Agents↗
PubMed1998

Predictors and outcome of admission for invasive Streptococcus pneumoniae infections at a Canadian children's hospital.

Rates of admission for invasive Streptococcus pneumoniae infection in children vary considerably between institutions. We performed a retrospective study to investigate factors used in the decision to admit patients with invasive S. pneumoniae infection to Alberta Children's Hospital. Of 254 patients who were initially assessed in the emergency department, 38.2% were admitted to the hospital. Significant risk factors for admission as determined by a logistic regression model included murmur (odds ratio [OR], 18.98; 95% confidence interval [CI], 4.08-88.23), focal infection (OR, 11.41; 95% CI, 5.07-25.67), and older age (OR, 2.72; 95% CI, 1.03-7.17). Higher hemoglobin level (OR, 0.96; 95% CI, 0.93-0.99) and temperature of > 38.5 degrees C (OR, 0.39; 95% CI, 0.18-0.85) were associated with a lower risk of admission. Two patients died (case-fatality rate, 0.7%). Despite the low rate of admission for invasive S. pneumoniae infections at our hospital, the mortality rate was comparable with those at institutions with higher rates of admission, thus suggesting that the factors we identified may be useful in deciding whether to admit patients with (or who are at high risk for) invasive S. pneumoniae infections.

Canada↗
PubMed1998

The use of Streptococcus pneumoniae nasopharyngeal isolates from healthy children to predict features of invasive disease.

BACKGROUND: The role of sampling nasopharyngeal carriage isolates of Streptococcus pneumoniae to determine characteristics of isolates causing invasive disease has not been established. METHODS: Data were compared from two 1995 studies of S. pneumoniae in Metropolitan Toronto and Peel Region (population, 3.1 million). The first was a prospective survey of nasopharyngeal (NP) carriage in child care centers. The second was a prospective surveillance for all cases of invasive disease. RESULTS: There were 545 NP S. pneumoniae isolates obtained from 532 children and 96 cases of invasive S. pneumoniae disease in children. The prevalences of reduced antibiotic susceptibility in the NP carriage and invasive studies, respectively, were: penicillin (16% vs. 11%, P=0.29); erythromycin (12% vs. 7%, P=0.25); and multiresistant (16% vs. 12%, P=0.34). The power to rule out a difference between the groups was <30% for each comparison. Trimethoprim/sulfamethoxazole resistance was more common in NP carriage isolates than invasive isolates (38% vs. 23%, P=0.02). Serotype 14 was more common in invasive isolates, whereas serogroup 6 was more common in NP carriage isolates. Antibiotic-resistant isolates were predominantly serogroups 6, 19 and 23 in both studies. CONCLUSIONS: Nasopharyngeal carriage isolates of S. pneumoniae reflect the antibiotic susceptibility rates of invasive isolates found in the same period for most antibiotics. However, even a large study like this may have limited power to detect a difference. The most common NP carriage serotypes are the same as the invasive isolates, although the rank order of specific serotypes is different. Routine surveys of S. pneumoniae NP carriage are not feasible because of the cost of serotyping and limited power of the observations, unless sample sizes are extremely large.

Age Factors↗
PubMed1998

Prevalence and characterization of the mechanisms of macrolide, lincosamide, and streptogramin resistance in isolates of Streptococcus pneumoniae.

Of a total of 147 erythromycin-resistant Streptococcus pneumoniae isolates, 64 (43.5%) were resistant to erythromycin, clindamycin, and streptogramin B (MLSB phenotype), 57 of which possessed the ermB gene. Eighty-two (55.8%) were resistant to erythromycin alone (M phenotype), 81 of which possessed the mefE gene. One was erythromycin and streptogramin B resistant but susceptible to clindamycin (MS phenotype) and possessed neither the erm gene nor the mefE gene.

Anti-Bacterial Agents↗
PubMed1998

Antibiotic-resistant Streptococcus pneumoniae. Implications for medical practice.

OBJECTIVE: To review the definition and prevalence of antibiotic-resistant Streptococcus pneumoniae, its links with antibiotic prescribing, data on antibiotic prescribing and prescribing appropriateness, and evidence-based treatment guidelines for common respiratory tract syndromes. QUALITY OF EVIDENCE: Primary studies consist of cross-sectional surveys and case-control studies. Treatment guidelines are based on clinical trials, meta-analyses, and cohort studies. Study designs were appropriate for the specific study questions. MAIN FINDINGS: The increasing prevalence of penicillin-resistant S pneumoniae is concurrent with increasing antibiotic prescribing. Individual patients show a twofold to ninefold increase in nasopharyngeal carriage of resistant bacteria or invasion with resistant bacteria (among those who have received antibiotics in the preceding 3 months). Cross-sectional data as well as data from medicaid and drug databases attest to overprescribing of antibiotics for respiratory tract infections. Physician surveys and focus groups blame this on parental pressure for antibiotic prescriptions. However, parents in focus groups and surveys deny they pressure their physicians and indicate their main purpose for office visits is to obtain a diagnosis and to seek reassurance that their children are not seriously ill. Evidence-based guidelines suggest treatment strategies that would reduce antibiotic prescribing. CONCLUSIONS: The few antibiotics that can be used with resistant organisms are expensive and are increasingly being needed. To control the rise of antibiotic resistance, it is important to limit antibiotic overprescribing.

Anti-Bacterial Agents↗
PubMed1996

Efficacy of bronchodilator therapy in bronchiolitis. A meta-analysis.

OBJECTIVE: To determine if bronchodilators are efficacious in treating bronchiolitis. DATA SOURCES: A search of bibliographic databases (MEDLINE, Excerpta Medica, and Reference Update) for bronchiolitis and albuterol or ipratropium bromide, or adrenergic agents or bronchodilator agents. Reference lists were also used. STUDY SELECTION: Randomized, placebo-controlled trials of bronchodilator treatment in bronchiolitis were selected by 2 investigators. Fifteen of 89 identified publications met the selection criteria. DATA EXTRACTION: Investigators independently abstracted data for 3 outcomes: clinical score, oxygen saturation, and hospitalization. Clinical score was measured as a dichotomous variable (score +/- improved) or continuous variable (average score). DATA SYNTHESIS: For primary analysis, data were pooled from 8 trials of children with first-time wheezing. The effect size for average score was -0.32 (95% confidence interval [CI], -0.54 to -0.11; P < .01), favoring treatment; the relative risk for score +/- improved was 0.76 (95% CI, 0.60 to 0.95; P = .02), favoring treatment. Bronchodilators had no effect on hospitalization (relative risk, 0.85; 95% CI, 0.47 to 1.53; P = .58), but co-interventions may have been administered prior to this outcome. The results for oxygen saturation were too varied to allow pooling of the results. Secondary analyses were performed on 4 outpatient trials of children with first-time wheezing, 7 trials in which only nebulized beta-agonists were used, and on all 15 trials identified. The results were similar, but the data varied more. CONCLUSION: Bronchodilators produce modest short-term improvement in clinical features of mild or moderately severe bronchiolitis.

Albuterol↗
PubMed1995

Association of Ureaplasma urealyticum colonization with chronic lung disease of prematurity: results of a metaanalysis.

OBJECTIVES: We performed a metaanalysis to determine whether there is an association between Ureaplasma urealyticum and chronic lung disease of prematurity (CLD); most studies involved small sample sizes, and the reported lack of statistical significance could have been due to inadequate power. METHODS: Articles were identified from the literature through a search of MEDLINE, Excerpta Medica, and Reference Update, with the search terms "Ureaplasma urealyticum," "CLD," and "bronchopulmonary dysplasia." The search was initially conducted in June 1994 and updated in March 1995. Abstracts were identified through a hand search of proceedings from two meetings for the years 1987 through 1994. Summary data on frequency of CLD in U. urealyticum-colonized and uncolonized babies were independently determined by the three authors. Preterm and term neonates were included. Colonization required recovery of U. urealyticum from a respiratory or surface specimen. The presence of CLD at 28 or 30 days was determined. RESULTS: Seventeen publications comprising 13 full publications and 4 abstracts were included in the analysis. The estimates for relative risk (RR) exceeded one in all studies, although the lower confidence interval included one in seven studies. The RR for the development of CLD in colonized neonates was 1.72 (95% confidence interval, 1.5 to 1.96) times that for uncolonized neonates. The RR was not significantly different for abstracts versus full publications; studies focusing on extremely premature, low birth weight neonates versus studies including all neonates; and studies in which only endotracheal aspirates were used to define colonization versus others. The RR since surfactant use was somewhat lower than in studies in which receipt of surfactant was unknown. CONCLUSIONS: This metaanalysis supports a significant association between U. urealyticum colonization and subsequent development of CLD. A randomized, controlled trial showing a reduction in CLD through the use of an antibiotic effective against U. urealyticum would provide further support of a causative role for this agent.

Chronic Disease↗
PubMed1992

Oxygen therapy in sickle cell disease.

The effect of oxygen therapy on the number of irreversibly (ISC) and reversibly (RSC) sickled cells was studied in patients with sickle cell anemia. Inhalation of 50% oxygen in patients who were not in crisis produced a significant fall in RSCs and a lesser fall in ISCs. Twenty-five subjects in sickle cell crisis were chosen at random to receive either oxygen (15 patients) or air (10 patients). Those who received oxygen showed a significant reduction in RSCs, but not in ISCs. No significant change in RSCs or ISCs occurred in the group who received air. Despite the reduction in RSCs in the oxygen-treated group, there was no significant difference between the air and oxygen groups in the duration of severe pain, opioid administration, and hospitalization. It was also observed that crisis was associated with arterial desaturation and a reduction in the number of RSCs. We conclude that, although RSCs may be involved in the pathophysiology of sickle cell crisis, reduction in RSCs by oxygen therapy in these studies did not result in any reduction in the duration of crisis.

Adolescent↗