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Spijkerman J.,University Utrecht | Spijkerman J.,Research Center Linnaeus Institute | Prevaes S.M.P.J.,University Utrecht | Prevaes S.M.P.J.,Research Center Linnaeus Institute | And 8 more authors.
PLoS ONE | Year: 2012

Background: Shifts in pneumococcal serotypes following introduction of 7-valent pneumococcal conjugate vaccine (PCV-7) may alter the presence of other bacterial pathogens co-inhabiting the same nasopharyngeal niche. Methodology/Principal Findings: Nasopharyngeal prevalence rates of S. pneumoniae, S. aureus, H. influenzae and M. catarrhalis were investigated before, 3 and 4.5 years after introduction of PCV-7 in the national immunisation program in children at 11 and 24 months of age, and parents of 24-month-old children (n≈330/group) using conventional culture methods. Despite a virtual disappearance of PCV-7 serotypes over time, similar overall pneumococcal rates were observed in all age groups, except for a significant reduction in the 11-month-old group (adjusted Odds Ratio after 4.5 years 0.48, 95% Confidence Interval 0.34-0.67). Before, 3 and 4.5 years after PCV-7 implementation, prevalence rates of S. aureus were 5%, 9% and 14% at 11 months of age (3.59, 1.90-6.79) and 20%, 32% and 34% in parents (1.96, 1.36-2.83), but remained similar at 24 months of age, respectively. Prevalence rates of H. influenzae were 46%, 65% and 65% at 11 months (2.22, 1.58-3.13), 52%, 73% and 76% at 24 months of age (2.68, 1.88-3.82) and 23%, 30% and 40% in parents (2.26, 1.58-3.33), respectively. No consistent changes in M. catarrhalis carriage rates were observed over time. Conclusions/Significance: In addition to large shifts in pneumococcal serotypes, persistently higher nasopharyngeal prevalence rates of S. aureus and H. influenzae were observed among young children and their parents after PCV-7 implementation. These findings may have implications for disease incidence and antibiotic treatment in the post-PCV era. © 2012 Spijkerman et al. Source

Spijkerman J.S.,University Utrecht | van Gils E.J.M.,University Utrecht | Veenhoven R.H.,Spaarne Hospital | Hak E.,University of Groningen | And 4 more authors.
Emerging Infectious Diseases | Year: 2011

To evaluate the effectiveness of the 7-valent pneumococcal conjugate vaccine (PCV7) program, we conducted a cross-sectional observational study on nasopharyngeal carriage of Streptococcus pneumoniae 3 years after implementation of the program in the Netherlands. We compared pneumococcal serotypes in 329 prebooster 11-month-old children, 330 fully vaccinated 24-month-old children, and 324 parents with age-matched pre-PCV7 (unvaccinated) controls (ages 12 and 24 months, n = 319 and n = 321, respectively) and 296 of their parents. PCV7 serotype prevalences before and after PCV7 implementation, respectively, were 38% and 8% among 11-month-old children, 36% and 4% among 24-monthold children, and 8% and 1% among parents. Non-PCV7 serotype prevalences were 29% and 39% among 11-monthold children, 30% and 45% among 24-month-old children, and 8% and 15% among parents, respectively; serotypes 11A and 19A were most frequently isolated. PCV7 serotypes were largely replaced by non-PCV7 serotypes. Disappearance of PCV7 serotypes in parents suggests strong transmission reduction through vaccination. Source

Van Gils E.J.M.,University Utrecht | Veenhoven R.H.,Spaarne Hospital Hoofddorp | Hak E.,University Utrecht | Hak E.,University of Groningen | And 8 more authors.
JAMA - Journal of the American Medical Association | Year: 2010

Context: The rapid increase in multiresistant serotype19Aas a cause of invasive and respiratory pneumococcal disease has been associated in time with the widespread implementation of 7-valent pneumococcal conjugate vaccination (PCV-7) in several countries. Because spontaneous fluctuations in time and antibiotic selective pressuremayhave induced this serotype 19A increase, controlled studies are needed to assess the role of PCV-7. Objective: To examine the association of PCV-7 vaccination and nasopharyngeal acquisition of serotype 19A pneumococci, their clonal distribution, and antibiotic susceptibility. Design, Setting, and Patients: Post hoc per-protocol completer's analysis as part of a randomized controlled trial of nasopharyngeal Streptococcus pneumoniae carriage enrolling 1003 healthy newborns with follow-up to the age of 24 months in the Netherlands, which has low antibiotic resistance rates. The study was conducted before widespread PCV-7 implementation in infants, between July 7, 2005, and February 14, 2008. Nasopharyngeal swabs were obtained at the age of 6 weeks and at 6, 12, 18, and 24 months. Intervention: Infants were randomly assigned to receive 2 doses of PCV-7 at 2 and 4 months; 2 + 1 doses of PCV-7 at 2, 4, and 11 months; or no dosage (unvaccinated control group). Main Outcome Measure: Cumulative proportion of children with nasopharyngeal acquisition of a new serotype 19A strain from 6 through 24 months of age. Results: Nine hundred forty-eight children completed the study. Fifty-four nasopharyngeal serotype 19A carriage isolates from 318 in the 2-dose group, 66 isolates from 327 in the 2 + 1-dose group, and 33 isolates from 303 in the unvaccinated were collected from 6 weeks through 24 months. The cumulative proportion who tested positive for new nasopharyngeal serotype 19A acquisition from 6 through 24 months of age was significantly higher in those having received the 2 + 1-dose PCV-7 schedule (16.2%;95% confidence interval [CI], 12.6%-20.6%) vs those who were unvaccinated (9.2%; 95% CI, 6.5%-13.0%; relative risk [RR], 1.75;95%CI, 1.14-2.70) but not after a 2-dose schedule (13.2%; 95% CI, 9.9%-17.4%; RR, 1.43; 95% CI, 0.91-2.25). There were 28 different sequence types identified, including 6 new types. The proportion of children with new 19A acquisition who had used antibiotics in the last 6 months (18.7%) did not differ among groups. Five isolates were penicillin-intermediate susceptible and another 3 were nonsusceptible to erythromycin and azithromycin, all in the vaccine groups. Conclusion: A 2 + 1-dose PCV-7 schedule was associated with an increase in serotype 19A nasopharyngeal acquisition compared with unvaccinated controls. Trial Registration: clinicaltrials.gov Identifier: NCT00189020. ©2010 American Medical Association. All rights reserved. Source

Bruin J.P.,Regional Laboratory of Public Health | Kostrzewa M.,Bruker | Van Der Ende A.,University of Amsterdam | Badoux P.,Regional Laboratory of Public Health | And 3 more authors.
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2014

Generally accepted laboratory methods that have been used for decades do not reliably distinguish between H. influenzae and H. haemolyticus isolates. H. haemolyticus strains are often incorrectly identified as nontypeable Haemophilus influenzae (NTHi). To distinguish H. influenzae from H. haemolyticus we have created a new database on the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) bio-typer 2 and compared the results with routine determination of Haemophilus (growth requirement for X and V factor), and multilocus sequence typing (MLST). In total we have tested 277 isolates, 244 H. influenzae and 33 H. haemolyticus. Using MLST as the gold standard, the agreement of MALDI-TOF MS was 99.6 %. MALDI-TOF MS allows reliable and rapid discrimination between H. influenzae and H. haemolyticus. © 2013 Springer-Verlag Berlin Heidelberg. Source

Bruin J.P.,Regional Laboratory of Public Health | Diederen B.M.W.,Regional Laboratory of Public Health | IJzerman E.P.F.,Regional Laboratory of Public Health | Den Boer J.W.,Regional Laboratory of Public Health | Mouton J.W.,Radboud University Nijmegen
Diagnostic Microbiology and Infectious Disease | Year: 2013

Objectives: Routine use of disk diffusion tests for detecting antibiotic resistance in Legionella pneumophila has not been described. The goal of this study was to determine the correlation of MIC values and inhibition zone diameter (MDcorr) in clinical L. pneumophila isolates. Methods: Inhibition zone diameter of 183 L. pneumophila clinical isolates were determined for ten antimicrobials. Disk diffusion results were correlated with MICs as determined earlier with E-tests. Results: Overall the correlation of MIC values and inhibition zone diameters (MDcorr) of the tested antimicrobials is good, and all antimicrobials showed a WT distribution. Of the tested fluoroquinolones levofloxacin showed the best MDcorr. All macrolides showed a wide MIC distribution and good MDcorr. The MDcorr for cefotaxim, doxycycline and tigecycline was good, while for rifampicin and moxifloxacin, they were not. Conclusion: Overall good correlation between MIC value and disk inhibition zone were found for the fluoroquinolones, macrolides and cefotaxim. © 2013 Elsevier Inc.. Source

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