Incidence and etiology of community-acquired pneumonia in the elderly in a prospective population-based study.

BACKGROUND: We conducted a prospective population-based epidemiological study to prepare a setting for documentation of the efficacy of novel vaccines against pneumococcal (Pnc) community-acquired pneumonia (CAP) in the elderly. Specific objectives were to demonstrate setting feasibility, to construct a case definition for Pnc CAP, and to estimate its incidence. METHODS: We prospectively enrolled patients with clinical and radiological findings compatible with CAP at municipal on-call clinics serving an elderly population (age ≥ 65 y) of approximately 29,500. Sputum, urine, nasopharyngeal swab (NPS), and blood samples were analyzed using diverse methods for the identification of Pnc (culture, PCR, antigen tests, serology) and of other pathogens. The following case definition for Pnc CAP was derived: encapsulated Pnc in blood culture or in high-quality sputum culture or at least 2 of the following: positive urine Pnc antigen; ≥ 2-fold increase in serum anti-PsaA or anti-CbpA antibodies; encapsulated Pnc culture or LytA PCR in either sputum or NPS. RESULTS: We enrolled 490 clinical CAP patients during the 2-y follow-up, 53% of all clinical CAP patients in the source population; 323 were radiologically confirmed. The incidence of radiologically confirmed CAP was 5.5/1000 person-y (95% confidence interval (CI) 4.9-6.1) and 10.5/1000 person-y when adjusted for non-captured patients. The proportion of radiologically confirmed CAP caused by Pnc was estimated at 17%; i.e. 0.95/1000 person-y (95% CI 0.7-1.2) and 1.8 when adjusted for non-captured patients. CONCLUSIONS: We developed and documented a feasible methodology for capturing endpoints in a vaccine trial for the prevention of pneumonia. CAP incidence in the elderly population remains considerable and Streptococcus pneumoniae was one of the most commonly detected causative agents.

Comparative analysis of Streptococcus pneumoniae transmission in Portuguese and Finnish day-care centres.

BACKGROUND: Day-care centre (DCC) attendees play a central role in maintaining the circulation of Streptococcus pneumoniae (pneumococcus) in the population. The prevalence of pneumococcal carriage is highest in DCC attendees but varies across countries and is found to be consistently lower in Finland than in Portugal. We compared key parameters underlying pneumococcal transmission in DCCs to understand which of these contributed to the observed differences in carriage prevalence. METHODS: Longitudinal data about serotype-specific carriage in DCC attendees in Portugal (47 children in three rooms; mean age 2 years; range 1-3 years) and Finland (91 children in seven rooms; mean age 4 years; range 1-7 years) were analysed with a continuous-time event history model in a Bayesian framework. The monthly rates of within-room transmission, community acquisition and clearing carriage were estimated. RESULTS: The posterior mean of within-room transmission rate was 1.05 per month (Portugal) vs. 0.63 per month (Finland). The smaller rate of clearance in Portugal (0.57 vs. 0.73 per month) is in accordance with the children being younger. The overall community rate of acquisition was larger in the Portuguese setting (0.25 vs. 0.11 per month), in agreement with that the groups belonged to a larger DCC. The model adequately predicted the observed levels of carriage prevalence and longitudinal patterns in carriage acquisition and clearance. CONCLUSIONS: The difference in prevalence of carriage (61% in Portuguese vs. 26% among Finnish DCC attendees) was assigned to the longer duration of carriage in younger attendees and a significantly higher rate of within-room transmission and community acquisition in the Portuguese setting.

Pneumococcemia in children--a retrospective study before universal pneumococcal vaccinations.

AIM: To evaluate the incidence and characteristics of blood culture-positive occult pneumococcemia compared with blood culture-positive pneumococcal pneumonia in children. METHODS: In years 2001-2010, 105 children with positive blood cultures for Streptococcus pneumoniae were identified from hospital electronic files. The patient cards were retrospectively charted for clinical and laboratory data, and 38 patients had and 67 had not pneumonia. RESULTS: The annual incidence of pneumococcemia was, on average, 29.0/10 000 at 0-12 months, 5.3/10 000 at 13-24 months and 1.9/10 000 at 2-4 years of ages, with no increasing or decreasing trend. The incidence of bacteraemic pneumococcal pneumonia increased (p = 0.022) during the study period. The duration of fever before hospitalization (<24 h 73.9% vs. 25.0%, p = 0.022) and the duration of intravenous antibiotics, usually G-penicillin (median 72 vs. 96 h, p = 0.021) was shorter in pneumococcemia patients. On admission, blood leucocyte count was higher in pneumococcemia (mean 26.6 vs. 21.9 × 10E9/L, p = 0.012), but serum CRP was higher in pneumonia (median 160 vs. 67.4 mg/L, p < 0.001). The serotypes 6B and 14 caused 53.2% of pneumococcemia cases. CONCLUSION: The incidence of pneumococcemia was highest in 1-2-year-old children, and typical for pneumococcemia was rapid onset of fever, high blood leucocyte count and a modestly elevated CRP on admission.

From Quellung to multiplex PCR, and back when needed, in pneumococcal serotyping.

All currently available vaccines against Streptococcus pneumoniae are based on selections of the over 90 different serotypes, which underlines the importance of serotyping for surveillance and vaccine efficacy monitoring. In this study, we modified and validated a PCR-based scheme for deducing the serotypes of the invasive pneumococci isolated in Finland. For validation, 170 isolates were serotyped using the new protocol with six sequential multiplex PCRs for the deduction of serotypes, supplemented with Quellung testing when needed. The results were compared with those obtained by traditional serotyping methods. We found that 98.8% (168/170) of the isolates were correctly serotyped by the new protocol. Subsequently, the scheme was taken into regular use for serotyping the invasive pneumococci isolated in Finland for serotype-specific surveillance purposes and has been applied in the serotyping of more than 1,500 invasive isolates so far. The sequential multiplex PCRs (mPCRs) have given a result for over 99% of the isolates and allowed us to both handle samples in bulk and noticeably reduce the cost of reagents. While serotyping primarily by PCR is precise and effective, Quellung testing remains the most reliable way to discover possible discrepancies between the DNA deduced and the phenotypic serotype of an isolate. Since implementing the protocol for regular use, two serotype 19F PCR-positive isolates were found to be serotype 19A by the Quellung reaction. While a rare occurrence, this is an important observation, which prompted a revision of our serotyping protocol to prevent possible underreporting of serotype 19A, a potential replacement serotype following large-scale vaccination.

Nasopharyngeal carriage of Streptococcus pneumoniae and pneumococcal urine antigen test in healthy elderly subjects.

BACKGROUND: Children frequently carry Streptococcus pneumoniae (pneumococcus) in their nasopharynx, even when healthy. Lower carriage rates have been reported in adults and only sparse data are available for the elderly. We sampled healthy elderly subjects for nasopharyngeal carriage to assess the prevalence of pneumococcal carriage using various assays. METHODS: A deep nasopharyngeal swab sample was taken from 590 healthy elderly subjects aged ≥ 65 y. The samples were stored in STGG (skim milk-tryptone-glucose-glycerol) medium and cultured directly and after incubation in enrichment broth using routine identification methods. Real-time polymerase chain reaction (PCR) assays specific for pneumolysin and pneumococcal surface antigen A genes was performed on the same samples. Urine was also collected and assayed using the commercial Binax Streptococcus pneumoniae NOW urine antigen test. RESULTS: The prevalence of pneumococcal carriage in healthy elderly persons was 1.5% for encapsulated pneumococci and 5.3% for all presumptive pneumococci. The use of the enrichment broth did not increase the yield of positives. PCR assays gave higher numbers of positives, but pneumolysin PCR in particular gave probable false-positive results. Only 1 urine antigen test was positive, and this was in a person not carrying pneumococcus. CONCLUSIONS: Nasopharyngeal carriage of pneumococci in the elderly was rare. Identification of presumptive pneumococci in culture requires further confirmation, e.g. by serotyping. The urine antigen test was not affected by concurrent carriage. Low carriage prevalence suggests that encapsulated pneumococci detected in a respiratory tract sample during sickness may be the true cause of disease, since contamination from asymptomatic nasopharyngeal carriage seems unlikely.

Serotype-related variation in susceptibility to complement deposition and opsonophagocytosis among clinical isolates of Streptococcus pneumoniae.

The polysaccharide capsule is a major virulence factor of Streptococcus pneumoniae; it affects complement resistance and shields the bacterium from phagocytes. Certain capsular serotypes appear to be better able to cause invasive disease than others. Serotypes 1 and 5 are common causes of invasive disease but are rarely isolated from healthy carriers, whereas serotypes 6B and 23F are more frequently isolated from carriage than invasive disease. We have recently shown that serotypes 6B and 19F differ in resistance to complement C3 deposition and opsonophagocytic killing. In this study we assessed the complement resistance and susceptibility to opsonophagocytosis of several other serotypes targeted by the pneumococcal conjugate vaccines. Clinical isolates of serotypes 1, 4, 5, 14, 18C, and 23F were tested along reference strains of corresponding capsular types. The concentration of anticapsular antibodies required for opsonophagocytic killing correlated inversely with C3 deposition on the serotype. Serotype 1 was the most resistant of the clinical isolates to C3 deposition and, along with serotypes 5 and 19F, required the highest concentration of capsule antibodies for opsonophagocytic killing, whereas serotype 23F was the most sensitive to opsonophagocytosis. Sensitivity to C3 deposition and opsonophagocytosis was associated with serotype-specific mortality of invasive pneumococcal disease, suggesting that the primary pathogens, such as serotypes 1 and 5, are more resistant to complement and require a higher concentration of capsule antibodies for opsonophagocytic killing than the opportunistic serotypes such as 6B and 23F, which are associated with a more severe disease outcome.

Risk of invasive pneumococcal infections among working age adults with asthma.

BACKGROUND: Information about the risk of invasive pneumococcal infection (IPI) among adults with asthma is limited and inconsistent. To evaluate this association, a population-based case-control study was conducted. METHODS: Cases of IPI (Streptococcus pneumoniae isolated from blood or cerebrospinal fluid) were identified through national, population-based laboratory surveillance during 1995-2002. To maximise exclusion of chronic obstructive pulmonary disease, the analysis was limited to patients aged 18-49 years and 10 selected age-, sex- and health district-matched controls for each case from the Population Information System. Information on underlying medical conditions was obtained through linking surveillance data to other national health registries. Asthma requiring > or =1 hospitalisation in the past 12 months was defined as high risk asthma (HRA); low risk asthma (LRA) was defined as entitlement to prescription drug benefits and no hospitalisation for asthma in the past 12 months. RESULTS: 1282 patients with IPI and 12 785 control subjects were identified. Overall, 7.1% of cases and 2.5% of controls had asthma (6.0% and 2.4% had LRA whereas 1.1% and 0.1% had HRA, respectively. After adjustment for other independent risk factors in a conditional logistic regression model, IPI was associated with both LRA (matched OR (mOR) 2.8; 95% CI 2.1 to 3.6) and HRA (mOR, 12.3; 95% CI 5.4 to 28.0). The adjusted population-attributable risk was 0.039 (95% CI 0.023 to 0.055) for LRA and 0.01 (95% CI 0.0035 to 0.017) for HRA. CONCLUSIONS: Working age adults with asthma are at increased risk of IPI. In this population, approximately 5% of disease burden could be attributed to asthma. These findings support adding medicated asthma in adults to the list of indications for pneumococcal vaccination.

The development of a 16S rRNA gene based PCR for the identification of Streptococcus pneumoniae and comparison with four other species specific PCR assays.

BACKGROUND: Streptococcus pneumoniae is one of the most frequently encountered pathogens in humans but its differentiation from closely related but less pathogenic streptococci remains a challenge. METHODS: This report describes a newly-developed PCR assay (Spne-PCR), amplifying a 217 bp product of the 16S rRNA gene of S. pneumoniae, and its performance compared to other genotypic and phenotypic tests. RESULTS: The new PCR assay designed in this study, proved to be specific at 57 degrees C for S. pneumoniae, not amplifying S. pseudopneumoniae or any other streptococcal strain or any strains from other upper airway pathogenic species. PCR assays (psaA, LytA, ply, spn9802-PCR) were previously described for the specific amplification of S. pneumoniae, but psaA-PCR was the only one found not to cross-react with S. pseudopneumoniae. CONCLUSION: Spne-PCR, developed for this study, and psaA-PCR were the only two assays which did not mis-identify S. pseudopneumoniae as S. pneumoniae. Four other PCR assays and the AccuProbe assay were unable to distinguish between these species.

Temporal trends of antimicrobial resistance and clonality of invasive Streptococcus pneumoniae isolates in Finland, 2002 to 2006.

The antimicrobial resistance of Streptococcus pneumoniae, or pneumococcus, is a growing global problem. In our study, 3,571 invasive pneumococcal isolates, recovered from blood and cerebrospinal fluid samples from patients in Finland between the years 2002 and 2006, showed an increase in erythromycin nonsusceptibility from 16% to 28% (P < 0.0001) over the 5-year study period, as well as a doubling of penicillin nonsusceptibility from 8% to 16% (P < 0.0001). Erythromycin nonsusceptibility increased especially in isolates derived from 0- to 2-year-old children and was 46% for this age group in 2006. Although multiresistance, defined as nonsusceptibility to penicillin, erythromycin, and tetracycline, was fairly rare (5.1% in 2006), 38% of the erythromycin-nonsusceptible isolates were also penicillin nonsusceptible, while 74% of the penicillin-nonsusceptible isolates were nonsusceptible to erythromycin. In contrast to the situation in continental Europe, but mirroring that in North America, the most frequent macrolide resistance determinant carried by 56% of the tested macrolide-resistant pneumococci was the mef gene. Serotypes 14, 9V, 19A, 6B, and 19F were most frequently nonsusceptible to erythromycin or penicillin. The penicillin-resistant invasive isolates (n = 88) were genotyped by multilocus sequence typing, which revealed the presence of 25 sequence types, 9 of which were novel. The majority of the isolates were related to one of several globally disseminated penicillin- or multiresistant clones, most importantly the rlrA adhesion pilus carrying clones Spain(9V) ST156 and Taiwan(19F) ST236. The penicillin-resistant pneumococcal population in Finland is therefore a combination of internationally recognized genotypes as well as novel ones.

Defining the population-based burden of nosocomial pneumococcal bacteremia.

BACKGROUND: The characteristics, risk factors, and outcome of patients with nosocomial pneumococcal bacteremia (NPB) have not been described in large, population-based studies. METHODS: All episodes of invasive pneumococcal infections reported by Finnish clinical microbiology laboratories (positive blood or cerebrospinal fluid culture) from January 1, 1995, through December 31, 2002, were linked to data in national health care registries and vital statistics to obtain information on the patient's preceding hospitalizations, comorbidities, and outcome of illness. Pneumococcal bacteremia was defined as nosocomial if the first positive blood culture was obtained more than 2 days after hospital admission, or if the patient had been hospitalized for more than 2 days within 7 days of the first positive blood culture. RESULTS: Information on hospital admission was available for 4217 of 4357 persons (96.8%) with invasive pneumococcal infections. We identified 387 NPBs (9.7%) among 3973 pneumococcal bacteremias. Patients with NPB were older (median age, 67 years vs 52 years; P < .001) and were more likely to have at least 1 high-risk condition (other than age > or = 65 years), for which 23-valent pneumococcal polysaccharide vaccine is recommended (59.2% vs 34.6%; P < .001), compared with patients who had community-associated pneumococcal bacteremias. The case fatality proportion at 28 days was higher in patients with NPB than in those with community-associated pneumococcal bacteremias (23.8% vs 10.8%; P < .001). Pneumococcal serotypes included in 23-valent polysaccharide vaccine and 7-valent conjugate vaccine caused 71.5% and 46.1% of NPBs, respectively. CONCLUSIONS: A substantial proportion of pneumococcal bacteremias are health care associated. The high prevalence of conditions for which pneumococcal polysaccharide vaccine is recommended provides opportunities for strengthening prevention efforts in these patients at high risk of illness and death.

Treatment of acute otitis media with probiotics in otitis-prone children-a double-blind, placebo-controlled randomised study.

BACKGROUND & AIMS: To examine whether probiotics would reduce the occurrence or duration of acute otitis media (AOM), or the nasopharyngeal carriage of otitis pathogens in otitis-prone children. METHODS: During this double-blind, placebo-controlled, randomised, 24-week intervention, 309 otitis-prone children (10 months-6 years) consumed either one probiotic capsule (Lactobacillus rhamnosus GG and LC705, Bifidobacterium breve 99 and Propionibacterium freudenreichii JS) (n=155) or placebo (n=154) daily. Clinical examinations were carried out and nasopharyngeal samples taken three times. Parents recorded the symptoms of upper respiratory infection (URI) in a diary. RESULTS: Probiotic treatment did not reduce the occurrence (probiotic vs. placebo: 72% vs. 65%, OR=1.48, 95% CI 0.87-2.52, p=n.s.) or the recurrence ( three) of AOM episodes (18% vs. 17%, OR=1.04, 95% CI 0.55-1.96, p=n.s.). The median duration of AOM episodes was 5.6 (IQR 3.5-9.4) vs. 6.0 (IQR 4.0-10.5) days, respectively (p= n.s.). There was a tendency showing a reduction in the occurrence of recurrent (4 to 6) respiratory infections in the probiotic group (OR for 4 URIs: 0.56, 95%CI 0.31-0.99, p=0.046; OR for 6 URIs: 0.59, 95% CI 0.34 to 1.03, p=n.s.). Probiotics did not affect the carriage of Streptococcus pneumoniae or Haemophilus influenzae, but increased the prevalence of Moraxella catarrhalis (OR=1.79, 95% CI 1.06-3.00, p=0.028). CONCLUSIONS: Probiotics did not prevent the occurrence of AOM or the nasopharyngeal carriage of otitis pathogens in otitis-prone children. A tendency showing a reduction in recurrent respiratory infections must be confirmed in further studies.

Direct and Indirect Effectiveness of the 10-Valent Pneumococcal Conjugate Vaccine Against Carriage in a Cluster Randomized Trial.

Finnish invasive pneumococcal disease (FinIP) vaccine trial was designed to evaluate effectiveness of 10-valent pneumococcal conjugate vaccine (PHiD-CV10; GSK; Rixensart, Belgium). We conducted 2 satellite studies to evaluate ten-valent Pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) effectiveness against pneumococcal carriage in FinIP-vaccinated children (long-term direct and indirect effectiveness combined) and in their unvaccinated siblings (indirect effectiveness within the family). FinIP was a cluster randomized trial, where >47,000 children <19 months of age were recruited in 2009-2010. Children received PHiD-CV10 in 2/3, and control vaccine in 1/3 of clusters according to age-specific infant and catch-up schedules. We obtained nasopharyngeal samples from subgroups of FinIP-vaccinated children at 3-5 years of age in 2013 and their unvaccinated older siblings in 2011 and 2013, and compared carriage in PHiD-CV10 clusters to control clusters in parallel. National Vaccination Programme with PHiD-CV10 for all 3-month-old children started in 2010 resulting in 92% vaccination coverage. To investigate indirect effects, over 2200 nasopharyngeal swabs were obtained during each round from unvaccinated older siblings. In 2011, we observed a 29% (95% confidence interval: 6-47) reduction in vaccine-type carriage in siblings of PHiD-CV10 participants vaccinated according to infant schedules. Vaccine-type carriage prevalences were low with no differences observed in 2013, 3 years after PHiD-CV10 introduction. For estimation of combined direct and indirect effectiveness, 1550 swabs from FinIP-vaccinated children were obtained in 2013. We observed a reduction of 54% (95% confidence interval: 34-68) in vaccine-type carriage in PHiD-CV10-vaccinated children. This study was the first randomized trial to show the indirect effect of extended valency pneumococcal conjugate vaccination on carriage. Also, long-term effectiveness against vaccine-type carriage was demonstrated in vaccinated children.

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.

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.

Effectiveness of the 10-Valent Pneumococcal Nontypeable Haemophilus influenzae Protein D-Conjugated Vaccine (PHiD-CV) Against Carriage and Acute Otitis Media-A Double-Blind Randomized Clinical Trial in Finland.

UNLABELLED: After administering the 10-valent pneumococcal polysaccharide nontypeable Haemophilus influenzae protein D-conjugated vaccine (PHiD-CV) to children aged 2-18 months, we observed a reduction in vaccine-type nasopharyngeal carriage, resulting in a reduction of overall pneumococcal nasopharyngeal carriage, which may be important for indirect vaccine effects. We noted a trend toward reduction of acute otitis media. BACKGROUND: This trial (ClinicalTrials.gov identifier NCT00839254), nested within a cluster-randomized double-blind invasive pneumococcal disease effectiveness study in Finland (ClinicalTrials.gov identifier NCT00861380), assessed the effectiveness of the 10-valent pneumococcal polysaccharide nontypeable Haemophilus influenzae protein D-conjugated vaccine (PHiD-CV or PCV10) against bacterial nasopharyngeal carriage and acute otitis media (AOM). METHODS: Infants (aged 6 weeks to 6 months) received the PHiD-CV or a control vaccine (hepatitis B) (schedule 3+1 or 2+1). Nasopharyngeal swabs were collected at 4 time points post-vaccination from all of the infants and at pre-vaccination from a subset. Parent-reported physician-diagnosed AOM was assessed from first vaccination until last contact (mean follow-up, 18 months). Vaccine effectiveness (VE) was derived as (1 - relative risk)*100, accounting for cluster design in AOM analysis. Significant VE was assessed descriptively (positive lower limit of the non-adjusted 95% confidence interval [CI]). RESULTS: The vaccinated cohort included 5093 infants for carriage assessment and 4117 infants for AOM assessment. Both schedules decreased vaccine-serotype carriage, with a trend toward a lesser effect from the 2+1 schedule ( VE across timpoints 19%-56% [3+1] and 1%-38% [2+1]). Trends toward reduced pneumococcal carriage (predominantly vaccine serotypes 6B, 14, 19F, and 23F), decreased carriage of vaccine-related serotype 19A, and small increases at later time points (ages 14-15 months) in non-vaccine-serotype carriage were observed. No effects on nontypeable Haemophilus influenzae, Staphylococcus aureus, or Moraxella catarrhalis carriage were observed. There were non-significant trends toward a reduction in the number of infants reporting AOM episodes (VE 3+1: 6.1% [95% CI, -2.7% to 14.1%] and 2+1: 7.4% [-2.8% to 16.6%]) and all AOM episodes (VE 3+1: 2.8% [-9.5% to 13.9%] and 2+1: 10.2% [-4.1% to 22.9%]). PHiD-CV was immunogenic and had an acceptable safety profile. CONCLUSIONS: We observed reduced vaccine-type pneumococcal carriage, a limited increase in non-vaccine-type carriage, and a trend toward AOM reduction.

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.

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.

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.

Long-term survival of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis as isolates and in nasopharyngeal specimens in frozen STGG storage medium.

We evaluated survival in WHO-recommended STGG storage medium of bacteria causing respiratory-tract infection. Streptococcus pneumoniae and Moraxella catarrhalis survived as single and mixed isolates stored at -70°C for 12.5 years, but Haemophilus influenzae less than 4 years. All the bacteria survived in the nasopharyngeal specimens at -70°C for 11 years.

Efficacy of the 7-Valent Pneumococcal Conjugate Vaccine Against Acute Otitis Media Caused by Serotype 6C Pneumococcus.

A new pneumococcal serotype 6C, earlier typed as 6A, was discovered in 2007. We retyped all 6A isolates to evaluate vaccine efficacy against 6C acute otitis media (AOM) in the phase III randomized, double-blind Finnish Otitis Media trial conducted in 1995-1999. Efficacy against 6C AOM was -1 (95% confidence interval: -248 to 71) during the per protocol follow-up period. The updated vaccine efficacy estimate for serotype 6A AOM was 65% (95% confidence interval: 31-82). Seven-valent pneumococcal conjugate vaccine offered excellent cross-protection against 6A AOM, but our data do not support cross-protection against 6C AOM.