Biomedical subjects

M Leinonen

Publications and source records attributed to M Leinonen.

At least 73 records · Page 4Linked to original sources

PubMed1999

Reliability of parental history of antibiotic use for Filipino children admitted with acute lower respiratory tract infection.

Parental history on antibiotic use and the urine antibacterial assay (UABA) result were compared in a study on Filipino children with acute lower respiratory tract infection (ALRI). Among 108 patients in whom urine for the UABA could be collected prior to starting antibiotic treatment in the hospital, 59 (55%) guardians reported preceding antibiotic use, 54% of whom were positive in the UABA. In another 37 (34%), the UABA result was positive, indicating nonreported use of antibiotics. Among 190 patients in whom urine could be collected only after intravenous administration of antibiotic, the UABA demonstrated large inhibition zones after the first dose in most patients but a negative result was seen in 14 cases. The inhibition zone radius was significantly smaller for chloramphenicol than for beta-lactam antibiotics (8.3 mm versus 16.1 mm after one dose; 95% confidence intervals = 7.0-9.7 and 14.9-17.2, respectively). Parental history on antibiotic use gives an underestimate of preceding antibiotic use in children with ALRI in the Philippines. The result partly explains the low yield of blood culture in many studies on ALRI, and stresses the need to develop new diagnostic methods not based on culture for those organisms highly sensitive to antibiotics such as Streptococcus pneumoniae and Haemophilus influenzae.

Acute Disease↗

PubMed1999

Microbiological investigations.

Causative diagnosis of pneumonia is problematic. The lack of a reliable gold standard for diagnosis has also made the development of new diagnostic methods for different microbes causing pneumonia difficult. Serologic methods are continuously used in the diagnosis of pneumonia caused by viruses and atypical bacteria. However, rapid diagnostic methods are urgently needed to guide clinicians to choose proper antibiotic treatment because resistant bacteria are emerging in different parts of the world.

Bacteriological Techniques↗

PubMed1998

Randomised trial of 23-valent pneumococcal capsular polysaccharide vaccine in prevention of pneumonia in middle-aged and elderly people. Swedish Pneumococcal Vaccination Study Group.

BACKGROUND: We assessed the effectiveness of a 23-valent pneumococcal vaccine in the prevention of pneumococcal pneumonia and of pneumonia overall in non-immunocompromised middle-aged and elderly people. METHODS: The prospective, multicentre, double-blind, randomised, placebo-controlled trial was carried out across departments of infectious diseases at six tertiary-care or university hospitals in Sweden. 691 non-immunocompromised patients aged 50-85 years who had been treated as inpatients for community-acquired pneumonia (CAP) were randomly assigned either 23-valent pneumococcal capsular polysaccharide vaccine or placebo (sodium chloride). We used Cox regression models to estimate the relative risks of pneumonia overall and pneumococcal pneumonia for the placebo group compared with the vaccine group. FINDINGS: 63 (19%) of 339 patients in the vaccine group and 57 (16%) of 352 patients in the placebo group developed a new pneumonia, corresponding to a relative risk over time for the placebo group compared with the vaccine group of 0.83 (95% CI 0.58-1.12, p=0.31). Pneumococcal pneumonia was diagnosed in 16 (4.5%) patients in the placebo group and in 19 (5.6%) in the vaccine group, corresponding to a relative risk for the placebo group of 0.78 (95% CI 0.40-1.51, p=0.45). We found no difference in the death rate between the two study groups. INTERPRETATION: The 23-valent pneumococcal polysaccharide vaccine did not prevent pneumonia overall or pneumococcal pneumonia in middle-aged and elderly individuals.

Aged↗

PubMed1998

Etiology of respiratory tract infection in adults in a general practice setting.

A prospective study was conducted over a 3-month winter period in three general practice clinics in an urban population in southern Israel to identify the etiological agents of respiratory tract infections (RTI) in adults. RTI was defined as an acute febrile illness with cough, coryza, sore throat or hoarseness. Serum samples were taken from all patients in both the acute and convalescent phases of their illness. Tests were conducted for detection of 17 microorganisms known to cause RTI, including serological tests for 16 known pathogens. An etiological diagnosis was established in 80 (66%) of the 122 patients who participated in the study. The distribution of the etiological agents was as follows: influenza B virus in 27 (22%) patients. Chlamydia pneumoniae in 22 (18%), Legionella spp. in 15 (12%), Mycoplasma pneumoniae in 13 (11%), influenza A virus in 11 (9%), Bordetella pertussis in 9 (7%), adenovirus in 4, Epstein Barr virus in 4, Haemophilus influenzae in 3, beta-hemolytic streptococci in 3, Streptococcus pneumoniae in 2, respiratory syncytial virus in 2, parainfluenza 1 virus in 2 and parainfluenza 2 virus in 1. No patients were found to be infected with Coxiella burnetii, Moraxella catarrhalis or parainfluenza 3 virus. More than one pathogen was identified in 27 (34%) patients in whom an etiological diagnosis was established. It is concluded that RTI is caused by a broad spectrum of etiological agents, a considerable number of patients having evidence of infection with more than one pathogen. The therapeutic significance of these findings should be elucidated in further studies.

Adult↗

PubMed1998

Animal models for Chlamydia pneumoniae infection.

Animal models are used extensively in the ongoing investigation of a possible causal link between Chlamydia pneumoniae infection and conditions such as asthma and cardiovascular disease. Respiratory infections have been studied in monkeys, while mouse and rabbit models have been used to study both respiratory and cardiovascular infections. The degree of disease induced in mice depends on the strain used, the virulence of the C. pneumoniae strain used, and the dose administered. A characteristic mononuclear pneumonitis occurs, although the infection is systemic and the agent is found outside the lungs, in the circulation, spleen and liver. The infective dose used in the model tends to produce persistent infection, with inflammation continuing after the agent can no longer be cultured from the lungs. In reinfected animals the titre of infective chlamydia in lungs is much diminished, but the inflammation can be quite marked. The continuous persistence of the agent can be demonstrated by polymerase chain reaction (PCR), or, in chronically infected animals, after immunosuppression with cortisone. New Zealand White (NZW) rabbits provide an experimental model, not only for lung infections, but also for C. pneumoniae-induced atherosclerosis. Three laboratories have now reported that after inoculation, plaques develop in the arterial walls of experimental animals on a normal diet. In addition, one laboratory has reported from their studies on atherosclerosis in apoE-deficient and normal mice, that the persistence of the agent in aortic walls could be seen. Further studies are needed to evaluate the effect of the strain of chlamydia and dosage used, the importance of reinfection, the effect of diet and the effect of antibiotic treatment in these models.

Animals↗

PubMed1998

Sinusitis in the common cold.

BACKGROUND: Acute community-acquired sinusitis is considered a bacterial complication of the common cold. Radiologic abnormalities in sinuses occur, however, in most patients with upper respiratory virus infections. OBJECTIVE: Assessment of the occurrence, clinical profile, laboratory findings, and outcome of radiologically confirmed sinusitis was carried out as part of a common cold study in young adults. METHODS: Clinical examinations and radiography of the paranasal sinuses were carried out on days 1, 7, and 21 in 197 patients with the common cold. The symptoms were recorded on diary cards on days 1 to 20. Ten viruses and 5 bacteria were studied as etiologic agents of common cold as reported earlier. Serum C reactive protein concentrations, erythrocyte sedimentation rates, and total white blood cell counts with differentials were determined in 40 randomized subjects on day 7. The effect of 6 days of intranasal fluticasone propionate treatment of the common cold in the prevention of sinusitis was analyzed. RESULTS: On day 7, 39% of patients with the common cold in the placebo group (n = 98) had sinusitis, which we would prefer to call viral sinusitis. The symptoms of patients with sinusitis and those without it were not clinically distinguishable. Viral infection was detected in 81.6% of patients with sinusitis. No significantly increased levels of antibodies to bacteria were detected. Serum C reactive protein concentrations, erythrocyte sedimentation rates, and white blood cell counts were low in patients with sinusitis. All patients made a clinical recovery within 21 days without antibiotic treatment. Fluticasone propionate treatment tended to prevent paranasal sinusitis, especially in rhinovirus-positive subjects. CONCLUSION: Viral sinusitis frequently occurs in the early days of the common cold, but it is a self-limited illness. The sinuses should not be imaged in patients with the common cold if the signs and symptoms of illness gradually become less severe and no specific signs suggestive of bacterial sinusitis occur.

Adult↗

PubMed1998

Serological evidence of an association between chlamydial infections and malignant lymphomas.

Chronic infections may predispose to malignant growth. Recently, serological markers of chronic Chlamydia pneumoniae infection have been associated with lung cancer. Our aim was to study the possible association between chronic chlamydial infections and malignant lymphomas. The present case-control study involved 72 patients with lymphoma (31 females and 41 males) and matched controls. 53 patients had non-Hodgkin's lymphoma (NHL) and 19 had Hodgkin's disease. The sera, collected at the time of diagnosis, were tested for IgG antibodies and immune complexes to C. pneumoniae and C. trachomatis by a microimmunofluorescence method and ELISA and for IgG antibodies and immune complexes to Helicobacter pylori by ELISA. The serological markers suggesting chronic chlamydial infection were associated with malignant lymphoma. The association was most evident for the presence of C. pneumoniae-specific immune complexes in NHL (OR = 7.3, 95% CI 2.2-25) and appeared to be limited to men. No association between H. pylori antibodies or immune complexes and malignant lymphomas could be demonstrated. Our study provides seroepidemiological evidence of an association between chronic chlamydial infections and lymphomas.

Adult↗

PubMed1998

Chlamydia pneumoniae-specific cell-mediated and humoral immunity in healthy people.

In this work, cell-mediated immunity to Chlamydia pneumoniae was studied in 157 healthy individuals using lymphoproliferative assay and serum antibodies were analysed by microimmunofluorescence techniques. The C. pneumoniae-specific IgG antibodies were elevated more frequently and the geometric mean titres for IgG (67.5 versus 44.1; P = 0.05) and IgA (14.9 versus 11.3; P = 0.025) antibodies were significantly higher in males than in females. However, no gender-dependent differences were observed in cellular reactivity to C. pneumoniae, since the median cellular responses were similar (stimulation indices 7.5) in men and women. Although the cell-mediated and humoral responses to C. pneumoniae did not correlate clearly, elevated IgG antibodies were associated with slightly higher lymphocyte proliferation in comparison to all subjects (15.5 versus 7.5) and significantly stronger in comparison to those with persistently elevated IgA (> 80) antibodies (15.5 versus 3.5; P = 0.023). Further studies are needed to evaluate a possible role of reduced cellular reactivity in the cause of chronic C. pneumoniae infection.

Adult↗

PubMed1998

IgG subclass-specific antibodies in Chlamydia pneumoniae infections.

IgG subclass-specific antibodies to Chlamydia pneumoniae and chlamydial lipopolysaccharide (LPS) were analysed in paired sera obtained from 15 patients with primary C. pneumoniae pneumonia and from 16 pneumonia patients with reinfection, as well as in single sera of 40 subjects with possible chronic C. pneumoniae infection and 40 healthy controls. The microimmunofluorescence (MIF) method was used to measure total IgG, IgM and IgG subclass-specific antibodies to C. pneumoniae protein antigens and enzyme immunoassay (EIA) to measure antibodies against the LPS antigen. By MIF, IgG1 antibodies to C. pneumoniae were demonstrated in all individuals of the 3 patient groups and also in all healthy controls. IgG2 subclass antibodies were not found by MIF. IgG3 antibodies were detected in 40% of patients with primary infection, in 31% of patients with reinfection, in 25% of those with chronic infection and in 8% of the controls. IgG4 antibodies were associated with acute C. pneumoniae infection and were found in 13% of primary infections and 31% of reinfections. The subclass pattern of LPS antibodies resembled that of protein antibodies measured by MIF: IgG1 was the most common subclass among the antibodies to LPS.

Acute Disease↗

PubMed1998

Aetiology of acute epiglottitis in adults.

In order to determine the aetiology of acute epiglottitis in adults, blood cultures, paired sera and a urine sample were obtained from 54 patients with fever and epiglottitis visualized by indirect laryngoscopy or by direct fibreoptic nasolaryngoscopy. Antibodies were determined against the capsular polysaccharide of Haemophilus influenzae type b (Hib), 3 pneumococcal antigens (a mixture of 23 capsular polysaccharides, C-polysaccharide and pneumolysin) and antistreptolysin O. Acute sera were examined by the polymerase chain reaction (PCR) for DNA of Hib and pneumococci. The urine samples were examined for Hib capsular antigen. Blood cultures were positive in 15 patients. In another 16, serology and/or PCR verified the aetiology. Hib was the cause in 14, pneumococci in 12 and group A streptococci in 5 patients. The aetiology remained unknown in 23/54 patients (43%). In conclusion, the addition of serology and PCR to blood cultures doubled the possibilities of verifying the aetiology of acute epiglottitis in adults.

Acute Disease↗

PubMed1998

Etiology of pneumonia and other common childhood infections requiring hospitalization and parenteral antimicrobial therapy. SE-TU Study Group.

The etiology of acute lower respiratory tract infections (mostly pneumonia) in children is well characterized, but these are only some of the community-acquired infections warranting parenteral antimicrobial therapy. We prospectively evaluated all such infections among children aged 3 months to 15 years by use of blood cultures, examination of nasopharyngeal aspirates, and serologies for 15 viral, 7 bacterial, and 1 protozoal agent. Immunocompromised patients and those with urinary tract infection, meningitis, or osteoarticular infection were excluded. In all, 170 children were included. The pathogenic agent was identified in 62% of the cases. Bacteria were detected in 54%, and a pneumococcus was found in 59% of the cases identified. Viruses were found in 15% overall. Sole bacterial or viral infections were detected in 47.1% and 8.1%, respectively. Since thorough screening established the etiology in less than two-thirds of patients ill enough to be hospitalized and treated parenterally, better diagnostics are needed, especially to identify those who would truly benefit from antimicrobial therapy.

Adolescent↗

PubMed1998

Weekly oral azithromycin as prophylaxis for agents causing acute respiratory disease.

Since the 1950s the U.S. military has used intramuscular injections of benzathine penicillin G (BPG) to control outbreaks of respiratory disease. In an effort to find an alternative prophylaxis, a randomized field trial was conducted among 1,016 male U.S. Marine trainee volunteers at high risk for respiratory disease. Participants were evaluated for evidence of acute respiratory infection by serological tests on pretraining and posttraining sera (63 days apart). Oral azithromycin prophylaxis (500 mg/w) outperformed BPG, preventing infection from Streptococcus pyogenes (Efficacy [E] = 84%; 95% confidence interval [CI], 63%-93%), Streptococcus pneumoniae (E = 80%; 95% CI, 50%-92%), Mycoplasma pneumoniae (E = 64%; 95% CI, 25%-83%), and Chlamydia pneumoniae (E = 58%; 95% CI, 15%-79%) in comparison with results in a no-treatment group. Azithromycin group subjects reported few side effects and less respiratory symptoms than the BPG and no-treatment groups. According to serological tests, oral azithromycin is an effective alternative prophylaxis to BPG for military populations.

Administration, Oral↗

PubMed1998

Reliability of disc diffusion susceptibility testing of Streptococcus pneumoniae and adjustment of laboratory-specific breakpoints. Finnish Study Group for Antimicrobial Resistance.

A routine disc diffusion method for detecting antibiotic-resistant Streptococcus pneumoniae was evaluated in 20 clinical microbiology laboratories. Fifty consecutive clinical isolates were tested by disc diffusion in each laboratory, and collected for MIC determinations. Participating laboratories used three disc types and several media; altogether 17 disc-medium-breakpoint reference combinations were used. Of the 781 isolates, 1.2% were resistant to penicillin and 4.2% were intermediately resistant. Eight of the nine resistant isolates had been classified as resistant to penicillin using a 1 microgram oxacillin disc screening test in the participating laboratories. If the MIC was taken as 0.125 mg/L, which is just above the intermediate breakpoint, 11 of 12 isolates were interpreted as susceptible to penicillin with the oxacillin disc test. The laboratories using Oxoid or Biodisk paper discs performed better in detecting co-trimoxazole resistance than the laboratories using Rosco tablets. Two control strains (one multiresistant and one susceptible) were each tested in the laboratories ten times. Based on these results laboratory-specific breakpoints for tetracycline were determined linearly. These adjusted breakpoints corrected three of five false-susceptible interpretations of the resistant clinical isolates and reduced the number of minor errors from 8.5% to 2.6%.

Anti-Bacterial Agents↗

PubMed1998

Etiology of childhood pneumonia: serologic results of a prospective, population-based study.

BACKGROUND: To investigate the etiology of pediatric community-acquired pneumonia, we conducted a prospective, population-based study covering the total population <15 years of age (n = 8851) in 4 municipalities in eastern Finland. MATERIALS AND METHODS: The number of patients was 201; chest radiographs were available for all cases and paired sera for serologic assays were available for >90% of cases. The methods included assays for antibody response to 3 pneumococcal antigens, specific pneumococcal immune complex assays and conventional antibody tests for mycoplasmal, chlamydial and viral infections. RESULTS: Serologic evidence of specific microbial etiology was obtained in 133 (66%) of the pneumonia patients. Bacterial infection was diagnosed in 102 cases (51%) and viral infection in 51 cases (25%). Streptococcus pneumoniae was the most common agent (57 cases; 28%), followed by Mycoplasma pneumoniae (44; 22%), respiratory syncytial virus (43; 21%) and Chlamydia spp. (29; 14%). Haemophilus influenzae was identified in only 6% and Moraxella catarrhalis in only 3% of the children. More than one specific infection was found in 51 patients (25%). The proportion of pneumococcal cases varied from 24 to 36% by age. Mycoplasma infections were seen mostly in patients > or =5 years and Chlamydia infections in patients > or =10 years of age. CONCLUSIONS: The results of our prospective, strictly population-based study confirm the importance of S. pneumoniae in the etiology of community-acquired pneumonia in children of all ages. M. pneumoniae and Chlamydia pneumoniae are important from the age of 5 years onwards.

Adolescent↗

PubMed1998

Pneumococcal immune complexes in the diagnosis of lower respiratory infections in children.

BACKGROUND: In recent years serologic methods have been applied to assess pneumococcal etiology of pneumonia and other respiratory tract infections. Antigen and antibody assays have shown to be insensitive, especially in young children. The aim of this study was to evaluate the usefulness of circulating immune complexes in the diagnosis of pneumococcal lower respiratory infection in children. MATERIAL AND METHODS: Pneumococcal immune complexes (IC) containing antibodies to species-specific C-polysaccharide, to mixtures of type-specific capsular polysaccharides or to a protein antigen, pneumolysin, were studied in the sera of 449 children with lower respiratory tract infection. RESULTS: Circulating ICs were found in 68 (15%) children; 46 (68%) of them were demonstrated in acute and 43 in convalescent serum. In 5 (7%) of the 68 IC-positive patients pneumococcal antigen was present in acute serum; those patients formed 18% of the 28 cases with antigenemia. An antibody response between paired sera to any of the 3 pneumococcal antigens studied was observed in 14 (21%) IC-positive children; they formed 23% of the 60 cases with an antibody response. In total ICs were positive in 51% of all the 134 pneumococcal cases diagnosed by any method. CONCLUSIONS: We conclude that the measurement of circulating ICs is more sensitive than other serologic methods for the diagnosis of pneumococcal lower respiratory infection. In infants, however, it was as insensitive as antigen and antibody assays.

Antibodies, Bacterial↗

PubMed1998

Immune responses to Chlamydia pneumoniae in twins in relation to gender and smoking.

This study investigated whether gender or smoking has an impact on immune responses to Chlamydia pneumoniae in generally healthy adults. A total of 129 twins (46 twin pairs and 37 single twins) from the Finnish Twin Cohort who had previously reported the highest discordance for smoking with their co-twins participated. C. pneumoniae-specific serum IgA and IgG antibody levels were measured by the micro-immunofluorescence test (micro-IF) at admission and 3 months later if the IgA level in the first sample was elevated. Cell-mediated immune (CMI) responses to C. pneumoniae and control antigens from heparinised blood samples were assessed by the lymphoproliferation (LP) assay. When all the subjects were pooled and analysed by gender and smoking status, marked differences in the humoral immune response between the genders were observed, irrespective of smoking status. When twin pairs solely were analysed, significantly elevated IgA antibody levels suggestive of persistent infection were found among the currently or formerly smoking men compared to their non-smoking co-twins. The CMI response showed a reciprocal trend with respect to humoral immunity. In conclusion, specific antibody levels were found to be higher in men than in women irrespective of smoking status, although smoking may further enhance the humoral response and depress the CMI response in men.

Adult↗

PubMed1998

Viruses and bacteria in the etiology of the common cold.

Two hundred young adults with common colds were studied during a 10-month period. Virus culture, antigen detection, PCR, and serology with paired samples were used to identify the infection. Viral etiology was established for 138 of the 200 patients (69%). Rhinoviruses were detected in 105 patients, coronavirus OC43 or 229E infection was detected in 17, influenza A or B virus was detected in 12, and single infections with parainfluenza virus, respiratory syncytial virus, adenovirus, and enterovirus were found in 14 patients. Evidence for bacterial infection was found in seven patients. Four patients had a rise in antibodies against Chlamydia pneumoniae, one had a rise in antibodies against Haemophilus influenzae, one had a rise in antibodies against Streptococcus pneumoniae, and one had immunoglobulin M antibodies against Mycoplasma pneumoniae. The results show that although approximately 50% of episodes of the common cold were caused by rhinoviruses, the etiology can vary depending on the epidemiological situation with regard to circulating viruses. Bacterial infections were rare, supporting the concept that the common cold is almost exclusively a viral disease.

Adenovirus Infections, Human↗

PubMed1998

Comparison of a pneumococcal common protein (PsaA) antibody ELISA and a PsaA immune complex ELISA for detection of pneumococcal serum antibody.

We examined and compared results from three assays, an enzyme-linked immunosorbent assay (ELISA) and two immune complex ELISAs for analysis of the serum antibody response to a native pneumococcal 37-kD common cell-wall protein by using acute- and convalescent-phase sera from 56 patients with community-acquired pneumonia. The sensitivities of the ELISA, the undissociated and dissociated immune complex assays were 85% (23 of 27), 78% (21 of 27) and 67% (18 of 27), respectively. To determine specificity, paired sera from patients with pneumonia of other bacterial etiologies were tested. The specificities were 83, 83 and 72% for the ELISA, undissociated immune complex, and dissociated immune complex, respectively. Based on this study, the sensitivities of the three assays were not statistically different. These tests could be used retrospectively to confirm invasive pneumococcal disease.

Adhesins, Bacterial↗