Search PubMed⌕ Search

Biomedical subjects

Tarja Kaijalainen

Publications and source records attributed to Tarja Kaijalainen.

13 recordsLinked to original sources
PubMed2006

Nasal middle meatal specimen bacteriology as a predictor of the course of acute respiratory infection in children.

AIMS: To test our hypothesis that children with potentially pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae or Moraxella catarrhalis) in the nasal middle meatus might have more prolonged symptoms of acute respiratory infection than children without such bacteria, we conducted a prospective cohort study of such children. MATERIALS AND METHODS: We recruited prospectively child volunteers between 6 and 13 years of age with acute respiratory infections present for fewer than 10 days. Nasal middle meatal bacterial culture was taken with a rigid endoscope at enrollment and again after 3 weeks and evaluated for presence or absence of 3 potential pathogens: S. pneumoniae, H. influenzae and M. catarrhalis. The subsequent persistence of acute symptoms (nasal discharge: clear/colored, nasal obstruction and cough) was determined by means of a diary. Viral etiology was studied with polymerase chain reaction methods. RESULTS: The 82 children had had symptoms for an average of 4 days (range, 1-10) at entry, and viruses were detected in 54% (39 of 72). The endoscopic procedure and bacteriologic sampling succeeded in all cases. Thirty-eight children (46%) had at least 1 of the 3 pathogens in the middle meatus specimen. The children with nasal pathogens present at entry had a significantly longer mean duration of symptoms than those with nonpathogenic bacteria (difference, 3.6 days; 95% confidence interval, 0.7-6.5; P = 0.025). The effect remained significant after adjustment for age, sex, allergic symptoms and the presence of virus (adjusted relative hazard of delayed recovery, 2.0; 95% confidence interval, 1.1-3.6). CONCLUSIONS: We found that the use of endoscopic swab culture sampling from the nasal middle meatus is well-tolerated by children older than 6 years of age and that it can be useful in selected situations to determine pathogenic bacteria in the culture of these specimens.

Acute Disease↗
PubMed2005

Presence of viral and bacterial pathogens in the nasopharynx of otitis-prone children. A prospective study.

OBJECTIVE: The purpose of the present study was to examine and follow up the presence of respiratory viral and bacterial pathogens in the nasopharynx of otitis-prone children during the cold season and compare the findings with the child's respiratory symptoms. METHODS: We enrolled 121 otitis-prone children, aged 10 months to 4 years for a prospective study. The nasopharyngeal swab (NPS) were studied at the baseline and after 12 and 24 weeks for respiratory viruses and at the baseline and after 24 weeks for bacteria. Presence of picorna(rhino-entero-parecho)-, influenza-, adenoviruses and Mycoplasma pneumoniae was detected by PCR. NPS specimens were cultured for Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis. Clinical data (the rate of respiratory symptom days, otitis media, tympanometry findings, day-care attendance and the number of siblings) were compared with microbiological data. RESULTS: Rhinovirus was found in 30% of the samples at the baseline, in 8% and in 19% of the samples after 12 and 24 weeks, respectively. Enterovirus was detected in 19% of the samples, in 21% and in 12% of samples after 12 and 24 weeks, respectively. Picornavirus positivity correlated with the respiratory symptoms but not with the number of otitis media or with abnormal tympanometry. Two samples were adeno- and three samples influenzavirus positive. Parechovirus and M. pneumoniae were negative in all samples. Rhinovirus positivity correlated with that of M. catarrhalis and S. pneumonia but not with H. influenzae. Microbiological positivity was not significantly associated with the type of day-care. CONCLUSIONS: Picornaviruses as well as bacteria were commonly found in the nasopharynx of otitis-prone children during the cold season, even in the absence of clinical symptoms.

Bacteria↗
PubMed2005

Are anticapsular antibodies the primary mechanism of protection against invasive pneumococcal disease?

BACKGROUND: Antibody to capsular polysaccharide has been the basis of several vaccines that offer protection against invasive disease from Streptococcus pneumoniae. The success of such vaccines has led to the inference that natural protection against invasive pneumococcal disease is largely conferred by anticapsular antibody. If this is so, one would expect that the decline in disease from different serotypes would vary significantly, and that the appearance of substantial concentrations of anticapsular antibodies would coincide temporally with the decline in age-specific incidence. METHODS AND FINDINGS: Using incidence data from the United States, we show that, on the contrary, the decline in incidence with age is quite similar for the seven most important serogroups, despite large differences in exposure in the population. Moreover, only modest increases in antibody concentration occur over the second and third years of life, a period in which serotype-specific incidence declines to less than 25% of its peak. We also present detailed data on the distribution of antibody concentrations in Israeli toddlers, which are consistent with the United States findings. The same conclusion is supported by new data on age-specific incidence in Finland, which is compared with published data on antibody acquisition in Finnish toddlers. CONCLUSION: We suggest some additional studies of the mechanisms of protection that could distinguish among potential alternative mechanisms, including acquired immunity to noncapsular antigens, maturation of nonspecific immune responses, or changes in anatomy or exposure.

Age Factors↗
PubMed2005

Real-time pneumolysin polymerase chain reaction with melting curve analysis differentiates pneumococcus from other alpha-hemolytic streptococci.

The majority of pneumococcal isolates can be identified by the conventional methods based on phenotypic characteristics. Occasionally, however, the differentiation of alpha-hemolytic streptococci from pneumococci, especially those isolated from nasopharynx, is problematic due to the discrepant results obtained by the conventional identification methods. Several gene technological methods based on the amplification of genes encoding pneumococcal virulence factors, such as pneumolysin (ply) and autolysin, have been used as additional identification methods. Recent studies have shown that especially the ply gene is frequently also present in nonpneumococcal alpha-hemolytic streptococci. In this study, we compared the commonly used phenotypic identification methods with nucleic acid-based methods, commercial AccuProbetrade mark, conventional pneumolysin polymerase chain reaction (Ply-PCR), and real-time Ply-PCR in the identification of alpha-hemolytic streptococcal strains isolated from 100 consecutive nasopharyngeal specimens. We also studied if melting curve analysis and sequencing of the amplification products of a ply gene fragment could be helpful in the identification. Our results suggest that the ply gene present in alpha-hemolytic streptococci differs from that present in pneumococcus, and that melting curve analysis would prove useful in the differentiation of these bacteria.

Bacterial Proteins↗
PubMed2005

Using multilocus sequence data to define the pneumococcus.

We investigated the genetic relationships between serotypeable pneumococci and nonserotypeable presumptive pneumococci using multilocus sequence typing (MLST) and partial sequencing of the pneumolysin gene (ply). Among 121 nonserotypeable presumptive pneumococci from Finland, we identified isolates of three classes: those with sequence types (STs) identical to those of serotypeable pneumococci, suggesting authentic pneumococci in which capsular expression had been downregulated or lost; isolates that clustered among serotypeable pneumococci on a tree based on the concatenated sequences of the MLST loci but which had STs that differed from those of serotypeable pneumococci in the MLST database; and a more diverse collection of isolates that did not cluster with serotypeable pneumococci. The latter isolates typically had sequences at all seven MLST loci that were 5 to 10% divergent from those of authentic pneumococci and also had distinct and divergent ply alleles. These isolates are proposed to be distinct from pneumococci but cannot be resolved from them by optochin susceptibility, bile solubility, or the presence of the ply gene. Complete resolution of pneumococci from the related but distinct population is problematic, as recombination between them was evident, and a few isolates of each population possessed alleles at one or occasionally more MLST loci from the other population. However, a tree based on the concatenated sequences of the MLST loci in most cases unambiguously distinguished whether a nonserotypeable isolate was or was not a pneumococcus, and the sequence of the ply gene fragment was found to be useful to resolve difficult cases.

Chromosome Mapping↗
PubMed2004

Association of clinical signs and symptoms with pneumococcal acute otitis media by serotype--implications for vaccine effect.

BACKGROUND: Clinical symptoms and signs in acute otitis media (AOM) may differ depending on the various pneumococcal serotypes causing the disease. Alteration in clinical presentation of AOM could be expected after wide-scale pneumococcal vaccinations if there were considerable differences between vaccine serotypes and nonvaccine serotypes. METHODS: In this study, data from 831 children in the control arm of the Finnish Otitis Media Vaccine Trial were used. The children were followed up prospectively in 8 study clinics from 2 to 24 months of age. If AOM was diagnosed, myringotomy was done, and middle ear fluid was aspirated for bacterial culture. Clinical symptoms and signs of AOM were routinely recorded on structured case report forms. RESULTS: Consistent with previous studies, 60% of pneumococcal episodes were caused by vaccine serotypes. There were no major differences between the clinical presentations of AOM due to different serotypes or serotype categories. However, earache was more often associated with AOM caused by vaccine and cross-reactive serotypes, compared with AOM caused by non-vaccine-related serotypes (42% vs. 29%; odds ratio, 1.66; 95% confidence interval, 1.02-2.70). CONCLUSIONS: Introduction of the currently available pneumococcal conjugate vaccine is unlikely to result in a remarkable alteration in the clinical presentation of pneumococcal AOM in infants.

Acute Disease↗
PubMed2004

Ultrastructure of Streptococcus pneumoniae after exposure to xylitol.

OBJECTIVES: Xylitol is a sugar alcohol which reduces the growth of Streptococcus pneumoniae and the adherence of pneumococci and Haemophilus influenzae to nasopharyngeal cells. Xylitol prevents acute otitis media but does not decrease nasopharyngeal carriage of pneumococci. We hypothesized that xylitol could affect the surface structures of viable pneumococci, which would further explain the mechanism of action of xylitol in preventing acute otitis media. METHODS: We exposed five strains of pneumococci to 0.5%-5% xylitol, 5% glucose, 5% fructose and 5% sorbitol or control medium (brain heart infusion) for 0.5-2 h and examined the ultrastructure of bacteria by electron microscopy. RESULTS: The cell wall of pneumococci became more diffuse, the polysaccharide capsule became ragged and the proportion of damaged pneumococci increased after exposure to xylitol for 2 h, but not after exposure to other sugars or control medium. The phenotype of all pneumococcal strains was opaque before xylitol exposure and became almost transparent both in xylitol and in control medium during the experiment. CONCLUSIONS: This study demonstrates further that xylitol has a harmful effect on pneumococci. The observed changes in the polysaccharide capsule and the cell wall of pneumococci could affect the adherence and virulence of pneumococci, explaining the good clinical efficacy of xylitol in the prevention of acute otitis media.

Culture Media↗
PubMed2004

Survival of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis frozen in skim milk- tryptone-glucose-glycerol medium.

In STGG (skim milk, tryptone, glucose, glycerol) medium at -80 degrees C, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis isolates survived for at least 3 years, and the same species have survived in nasopharyngeal swabs for at least 1.5 years. At -20 degrees C, S. pneumoniae and M. catarrhalis survived for 1.5 years, but H. influenzae survived for only 2 months.

Animals↗
PubMed2003

Isolation of pneumococcal DNA from nasopharyngeal samples for real-time, quantitative PCR: comparison of three methods.

BACKGROUND: Real-time PCR is a useful method for detecting and quantifying bacterial DNA in clinical samples. DNA extraction is a crucial step when performing quantitative PCR. METHODS: We compared three methods, QIAamp. The use of tradenames is for product identification purposes only and does not imply endorsement. DNA Mini kit, MagNAPure trade mark LC DNA Isolation Kit II together with PickPen trade mark magnetic particle transfer device, and KingFisher genomic DNA purification Kit with KingFisher mL instrument, for purification of Streptococcus pneumoniae DNA from 50 nasopharyngeal swab samples, collected into skim milk-tryptone-glucose-glycerin medium. Pneumococcal DNA was detected and quantified by real-time PCR and results were compared to culture findings. RESULTS: The 22 (44%) pneumococcal culture-positive specimens were all positive by PCR regardless of DNA extraction method used, except that one KingFisher-extracted sample was positive only when repeatedly tested. Additionally, 71%, 57%, and 82% of the culture-negative samples were positive by real-time PCR when DNA was extracted by QIAamp, MagNAPure-PickPen, and KingFisher methods, respectively. The number of genome equivalents detected by real-time PCR varied, but was mainly low in culture-negative samples. The sensitivities of culture and real-time PCR were hence compared by analyzing different dilutions of a pneumococcal suspension. Real-time PCR detected significantly higher numbers of genome equivalents than the numbers of bacteria detected by culture. CONCLUSIONS: The results indicate that the DNA extraction method used for quantitative PCR should be evaluated and that real-time PCR is more sensitive than bacterial culture for detecting pneumococcus in nasopharyngeal swab samples.

Bacteriological Techniques↗
PubMed2003

Comparison of five genotypic techniques for identification of optochin-resistant pneumococcus-like isolates.

Three PCR techniques (amplification of the psaA, ply, and lytA genes) and a commercial kit (AccuProbe [GenProbe, San Diego, Calif.], based on hybridization with the 16S rRNA gene), all four of which claimed to be specific for Streptococcus pneumoniae, were used to identify 49 alpha-hemolytic streptococcal isolates suspected of being pneumococci. The definite phenotypic identification of these organisms as S. pneumoniae was difficult when optochin susceptibility and the presence of a capsule were taken as markers. Furthermore, RsaI digestion of the amplified 16S rRNA gene was applied. All 49 strains were optochin resistant. Eleven of these were encapsulated and were identified as pneumococci by all tests. Twenty of the 38 unencapsulated strains were unambiguously identified as nonpneumococci by all tests. The identities of another 18 unencapsulated strains remained inconclusive due to highly variable reactions for all phenotypic and genotypic techniques applied. The AccuProbe test was positive for seven strains for which the results of the other tests were inconclusive. RsaI restriction of the amplified 16S rRNA gene confirmed the AccuProbe result for all strains, while the result of the psaA-specific PCR was in concordance with encapsulation for all strains. The results presented here indicate that identification problems continue to exist for some strains, despite the application of genotypic and phenotypic tests in combination. We found the psaA-specific PCR to be the genotypic technique best suited for the identification of genuine pneumococci and optochin-resistant pneumococci.

Bacterial Typing Techniques↗
PubMed2002

Evaluation of gene-technological and conventional methods in the identification of Streptococcus pneumoniae.

To find reliable methods able to identify the "difficult" Streptococcus pneumoniae isolates, an in-house polymerase chain reaction (PCR) for pneumolysin gene (Ply-PCR) and a commercial RNA hybridisation test (AccuProbe) were evaluated. Selected isolates of suspected pneumococci, sent for confirmation of identification and for serotyping, were classified into four groups based on their optochin sensitivity and capsule reaction. All isolates in Group 1, which consisted of 24 typical, optochin-sensitive, encapsulated pneumococcal strains, were positive in the Ply-PCR and AccuProbe tests. In Group 2, which consisted of 25 optochin-sensitive, but unencapsulated pneumococcal strains, all the isolates were positive in the Ply-PCR test, and 23 were positive in the AccuProbe test. In Group 3, which consisted of 15 atypical, optochin-resistant but encapsulated pneumococci, 12 of the isolates were positive in the Ply-PCR and 12 in the AccuProbe test, and 11 of these 12 strains were positive in both tests. In Group 4, which consisted of 36 equivocal optochin-resistant, unencapsulated isolates, 15 strains were positive in the Ply-PCR test and 8 strains in the AccuProbe test. As a conclusion, the Ply-PCR and AccuProbe tests identified similarly typical optochin-sensitive pneumococci, but gave partly controversial results about atypical pneumococci. Thus, they did not reliably help in the identification of suspected pneumococcal isolates lacking the conventional characteristics of pneumococcus.

Bacterial Capsules↗
PubMed2002

Rapid increase in macrolide resistance among penicillin non-susceptible pneumococci in Finland, 1996-2000.

The aims of this study were to evaluate the resistance patterns and serotypes/groups of penicillin non-susceptible pneumococci (PNSP) in Finland, and to determine phenotypes and resistance mechanisms of the erythromycin-resistant isolates. A total of 1190 PNSP were collected during 1996-2000 in Finland. The MICs of 18 antimicrobials were determined by the agar plate dilution method, and PCR was used to study the resistance mechanisms of the macrolide-resistant isolates. For serotyping, counterimmunoelectrophoresis and latex agglutination were used. Erythromycin resistance increased from 32% in 1996 to 62% in 2000 among PNSP in Finland. Multiresistance (co-resistance to erythromycin, tetracycline and co-trimoxazole) was present in 22% of the isolates in 1996 and in 40% in 2000. The most common macrolide resistance phenotype was the MLS(B) phenotype (72%), 25% had the M phenotype and 3% the MS phenotype. The MLS(B) and M phenotypes increased in the same proportion during the study period. All the MLS(B) isolates had the erm(B) gene, the M isolates the mef(A) gene, and in 11 MS isolates, ribosomal mutations were the cause of resistance. The most common serotypes/groups were 14, 19 and 6. We found a significant increase in multiresistance among PNSP within a short period of time in Finland. Although pneumococcal resistance to erythromycin was 11% in 2000, the same figure was 50% among the PNSP. The rise in erythromycin resistance is worrying, as macrolides are commonly used as first- and second-line drugs in pneumococcal infections.

Anti-Bacterial Agents↗