Groningen, Netherlands
Groningen, Netherlands

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Van Assen S.,University of Groningen | Holvast A.,University of Groningen | Benne C.A.,Laboratory for Infectious Diseases | Posthumus M.D.,University of Groningen | And 8 more authors.
Arthritis and Rheumatism | Year: 2010

Objective. For patients with rheumatoid arthritis (RA), yearly influenza vaccination is recommended. However, its efficacy in patients treated with rituximab is unknown. The objectives of this study were to investigate the efficacy of influenza vaccination in RA patients treated with rituximab and to investigate the duration of the possible suppression of the humoral immune response following rituximab treatment. We also undertook to assess the safety of influenza vaccination and the effects of previous influenza vaccination. Methods. Trivalent influenza subunit vaccine was administered to 23 RA patients who had received rituximab (4-8 weeks after rituximab for 11 patients [the early rituximab subgroup] and 6-10 months after rituximab for 12 patients [the late rituximab subgroup]), 20 RA patients receiving methotrexate (MTX), and 29 healthy controls. Levels of antibodies against the 3 vaccine strains were measured before and 28 days after vaccination using hemagglutination inhibition assay. The Disease Activity Score in 28 joints (DAS28) was used to assess RA activity. Results. Following vaccination, geometric mean titers (GMTs) of antiinfluenza antibodies significantly increased for all influenza strains in the MTX-treated group and in healthy controls, but for no strains in the rituximab-treated group. However, in the late rituximab subgroup, a rise in GMT for the A/H3N2 and A/H1N1 strains was demonstrated, in the absence of a repopulation of CD19+ cells at the time of vaccination. Seroconversion and seroprotection occurred less often in the rituximab-treated group than in the MTX-treated group for the A/H3N2 and A/H1N1 strains, while seroprotection occurred less often in the rituximab-treated group than in the healthy controls for the A/H1N1 strain. Compared with unvaccinated patients in the rituximab-treated group, previously vaccinated patients in the rituximab-treated group had higher pre- and postvaccination GMTs for the A/H1N1 strain. The DAS28 did not change after vaccination. Conclusion. Rituximab reduces humoral responses following influenza vaccination in RA patients, with a modestly restored response 6-10 months after rituximab administration. Previous influenza vaccination in rituximab-treated patients increases pre- and postvaccination titers. RA activity was not influenced. © 2010, American College of Rheumatology.


De Boer R.F.,Laboratory for Infectious Diseases | Ott A.,Laboratory for Infectious Diseases | Guren P.,Laboratory for Infectious Diseases | Guren P.,Laboratory of Medical Microbiology and Infectious Diseases | And 4 more authors.
Journal of Clinical Microbiology | Year: 2013

The presence of Campylobacter (or Campylobacter-like) species in stools from patients suspected of infectious gastroenteritis (n = 493) was investigated using real-time PCR for detection of Arcobacter butzleri (hsp60 gene), Campylobacter coli (ceuE gene), Campylobacter jejuni (mapA), five acknowledged pathogenic Campylobacter spp. (C16S-Lund assay), and the Campylobacter genus (C16S-LvI assay). In total, 71.4% of the samples were positive for Campylobacter DNA (n = 352) by a Campylobacter genus-specific (C16S-LvI) assay. A total of 23 samples (4.7%) were positive in the C16S-Lund assay, used for detection of C. jejuni, C. coli, C. lari, C. upsaliensis, and C. hyointestinalis. Subsequent identification of these samples yielded detection frequencies (DF) of 4.1% (C. jejuni), 0.4% (C. coli), and 0.4% (C. upsaliensis). The DF of A. butzleri was 0.4%. Interestingly, sequencing of a subgroup (n = 46) of C16S-LvI PCR-positive samples resulted in a considerable number of Campylobacter concisus-positive samples (n = 20). PCR-positive findings with the C16S-Lund and C. jejuni/C. coli-specific assays were associated with more serious clinical symptoms (diarrhea and blood). Threshold cycle (CT) values of C. jejuni/C. coli PCR-positive samples were comparable to those of the C16S-Lund PCR (P = 0.21). CT values for both assays were significantly lower than those of the C16S-LvI assay (P < 0.001 and P < 0.00001, respectively). In conclusion, this study demonstrated that in combination, the C. jejuni/C coli-specific assays and the C16S-Lund assay are both useful for routine screening purposes. Furthermore, the DF of the emerging pathogen C. concisus was at least similar to the DF of C. jejuni. Copyright © 2013, American Society for Microbiology. All Rights Reserved.


Bruins M.J.,Laboratory of Clinical Microbiology and Infectious Diseases | Wolfhagen M.J.H.M.,Laboratory of Clinical Microbiology and Infectious Diseases | Schirm J.,Laboratory for Infectious Diseases | Ruijs G.J.H.M.,Laboratory of Clinical Microbiology and Infectious Diseases
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2010

Worldwide noroviruses are an important cause of gastroenteritis and are major agents of both sporadic as well as epidemic infection. Because of the rapid transmission of the virus, early detection is essential. Until recently, the available test methods for the detection in stool were enzyme immunoassays and real-time reverse transcription polymerase chain reaction (RT-PCR), both of which take several hours to perform. We evaluated the rapid immunochromatographic test RIDA®QUICK Norovirus for the detection of norovirus in the stool of patients with acute gastroenteritis. This test is easy to perform and read and only takes 20 min. The sensitivity and specificity compared to RT-PCR results and the positive and negative predictive values were 57.1%, 99.1%, 93.3% and 91.2%, respectively. The rapid test is useful for quick screening, but a negative result should be followed up by RT-PCR. © 2010 Springer-Verlag.


de Greeff S.C.,National Institute for Public Health and the Environment | de Melker H.E.,National Institute for Public Health and the Environment | van Gageldonk P.G.M.,National Institute for Public Health and the Environment | Schellekens J.F.P.,Laboratory for Infectious Diseases | And 4 more authors.
PLoS ONE | Year: 2010

Background: In many countries, the reported pertussis has increased despite high vaccination coverage. However, accurate determination of the burden of disease is hampered by reporting artifacts. The infection frequency is more reliably estimated on the basis of the prevalence of high IgG concentrations against pertussis toxin (IgG-Ptx). We determined whether the increase in reported pertussis in the last decade is associated with an increase in the number of infections. Methodology/Principal Findings: In a cross-sectional population-based serosurveillance study conducted in 2006-07, from a randomly selected age-stratified sample of 7,903 persons, serum IgG-Ptx concentrations were analyzed using a fluorescent bead-based multiplex immuno assay. In 2006-07, 9.3% (95%CI 8.5-10.1) of the population above 9 years of age had an IgG-Ptx concentration above 62.5 EU/ml (suggestive for pertussis infection in the past year), which was more than double compared to 1995-96 (4.0%; 95%CI 3.3-4.7). The reported incidence showed a similar increase as the seroprevalence between both periods. Conclusions: Although changes in the vaccination program have reduced pertussis morbidity in childhood, they have not affected the increased infection rate in adolescent and adult pertussis. Indeed, the high circulation of B. pertussis in the latter age-categories may limit the effectiveness of pediatric vaccination. © 2010 de Greeff et al.


Hira V.,Erasmus MC Sophia Childrens Hospital | Sluijter M.,Erasmus MC Sophia Childrens Hospital | Goessens W.H.F.,Erasmus MC Sophia Childrens Hospital | Ott A.,Laboratory for Infectious Diseases | And 3 more authors.
Journal of Clinical Microbiology | Year: 2010

Coagulase-negative staphylococci (CoNS) are a major cause of sepsis in neonatal intensive care units (NICU) worldwide. Infecting strains of these commensal bacteria may originate from NICU personnel. Therefore, we studied the characteristics of CoNS isolates from NICU personnel and compared them to those of isolates from the general population and from sepsis patients. Furthermore, we studied the epidemiological effect on CoNS carriage of NICU personnel after a period of absence. In our study, we isolated CoNS from the thumbs of NICU personnel every 2 weeks during the summer of 2005 and sampled personnel returning from vacation and a control group from the general population. Furthermore, we collected sepsis isolates from this period. Isolates were tested for antibiotic resistance, mecA and icaA carriage, biofilm production, and genetic relatedness. We found that mecA and icaA carriage as well as penicillin, oxacillin, and gentamicin resistance were significantly more prevalent in CoNS strains from NICU personnel than in community isolates. Similar trends were observed when postvacation strains were compared to prevacation strains. Furthermore, genetic analysis showed that 90% of the blood isolates were closely related to strains found on the hands of NICU personnel. Our findings revealed that CoNS carried by NICU personnel differ from those in the general population. Hospital strains are replaced by community CoNS after a period of absence. NICU personnel are a likely cause for the cross-contamination of virulent CoNS that originate from the NICU to patients. Copyright © 2010, American Society for Microbiology. All Rights Reserved.


De Boer R.F.,Laboratory for Infectious Diseases | Ott A.,Laboratory for Infectious Diseases | Kesztyus B.,Laboratory for Infectious Diseases | Kooistra-Smid A.M.D.,Laboratory for Infectious Diseases
Journal of Clinical Microbiology | Year: 2010

The detection of bacterial and parasitic gastrointestinal pathogens through culture and microscopy is laborious and time-consuming. We evaluated a molecular screening approach (MSA) for the detection of five major enteric pathogens: Salmonella enterica, Campylobacter jejuni, Giardia lamblia, Shiga toxin-producing Escherichia coli (STEC), and Shigella spp./enteroinvasive E. coli (EIEC), for use in the daily practice of a clinical microbiology laboratory. The MSA consists of prescreening of stool specimens with two real-time multiplex PCR (mPCR) assays, which give results within a single working day, followed by guided culture/microscopy of the positive or mPCR-inhibited samples. In the present 2-year overview, 28,185 stool specimens were included. The MSA was applied to 13,974 stool samples (49.6%), whereas 14,211 samples were tested by conventional methods only (50.4%). The MSA significantly increased the total detection rate compared to that of conventional methods (19.2% versus 6.4%). The detection of all included pathogens, with the exception of S. enterica, significantly improved. MSA detection frequencies were as follows: C. jejuni, 8.1%; G. lamblia, 4.7%; S. enterica, 3.0%; STEC, 1.9%; and Shigella spp./EIEC, 1.4%. The guided culture/microscopy was positive in 76.8%, 58.1%, 88.9%, 16.8%, and 18.1% of mPCR-positive specimens, respectively. Of all mPCRs, only 1.8% was inhibited. Other findings were that detection of mixed infections was increased (0.9% versus 0.02%) and threshold cycle (CT) values for MSA guided culture/microscopy-positive samples were significantly lower than those for guided culture/microscopy-negative samples. In conclusion, an MSA for detection of gastrointestinal pathogens resulted in markedly improved detection rates and a substantial decrease in time to reporting of (preliminary) results. Copyright © 2010, American Society for Microbiology. All Rights Reserved.


Wisselink G.J.,Laboratory for Infectious Diseases | van Zanten E.,Laboratory for Infectious Diseases | Kooistra-Smid A.M.D.,Laboratory for Infectious Diseases
Journal of Microbiological Methods | Year: 2011

Traditionally, laboratory detection and identification of dermatophytes consists of culture and microscopy which yields results within approximately 2-6 weeks. In 2007 our medical microbiological diagnostic laboratory implemented a molecular method for the detection of dermatophytes. A real-time PCR assay was developed which simultaneously detects and identifies the most prevalent dermatophytes directly in nail, skin and hair samples and has a turnaround time of less than two days. For 1437 clinical samples, received by our diagnostic laboratory, we compared the results obtained from both culture and real-time PCR. This study showed that real-time PCR significantly increased the detection rate of dermatophytes compared to culture. Furthermore, excellent concordance between culture and real-time PCR identification was achieved. © 2011 Elsevier B.V.


De Greeff S.C.,National Institute for Public Health and the Environment | Mooi F.R.,National Institute for Public Health and the Environment | Westerhof A.,National Institute for Public Health and the Environment | Verbakel J.M.M.,St Elisabeth Hospital | And 6 more authors.
Clinical Infectious Diseases | Year: 2010

Background. We conducted a population-based, nation-wide, prospective study to identify who introduced pertussis into the household of infants aged ≤S6 months admitted to the hospital for pertussis in the Netherlands. Methods. During the period 2006-2008, a total of 560 household contacts of 164 hospitalized infants were tested by polymerase chain reaction, culture, and serological examination to establish Bordetella pertussis infection. Clinical symptoms and vaccination history were obtained by a questionnaire submitted during sample collection and 4-6 weeks afterwards. Results. Overall, 299 household contacts (53%) had laboratory-confirmed pertussis; 159 (53%) had symptoms compatible with typical pertussis infection, and 42 (14%) had no symptoms. Among children vaccinated with a whole-cell vaccine, 17 (46%) of 37 had typical pertussis 1-3 years after completion of the primary series, compared with 9 (29%) of 31 children who had been completely vaccinated with an acellular vaccine. For 96 households (60%), the most likely source of infection of the infant was established, being a sibling (41%), mother (38%), or father (17%). Conclusions. If immunity to pertussis in parents is maintained or boosted, 35%-55% of infant, cases could be prevented. Furthermore, we found that, 1-3 years after vaccination with whole-cell or acellular vaccine, a significant percentage of children are again susceptible for typical pertussis. In the long term, pertussis vaccines and vaccination strategies should be improved to provide longer protection and prevent transmission. © 2010 by the Infectious Diseases Society of America. All rights reserved.


De Greeff S.C.,National Institute for Public Health and the Environment | De Melker H.E.,National Institute for Public Health and the Environment | Westerhof A.,National Institute for Public Health and the Environment | Schellekens J.F.P.,Laboratory for Infectious Diseases | And 2 more authors.
Epidemiology | Year: 2012

BACKGROUND:: Despite >50 years of universal vaccination, pertussis remains the most prevalent vaccine-preventable infectious disease in developed countries. Pertussis is often mild in adults, but can run a severe course in young infants. METHODS:: Data on transmission of pertussis within households were captured in a population-based, nationwide, prospective study performed in the Netherlands between February 2006 and December 2009. We estimated the transmission rates of pertussis with a clinically confirmed infection in 140 households, using stochastic epidemic models. Parameter estimates were used to gauge the effect of vaccinating household members (cocooning) to prevent the infection in young infants. RESULTS:: Overall transmission rates in the household were high. Fathers were less susceptible than other household members (estimated relative susceptibility of fathers = 0.44 [95% confidence interval (CI) = 0.27-0.72]), whereas mothers may be more infectious to their infants than are other household members (estimated relative infectiousness of mothers = 3.9 [95% CI = 0.59-14]). Targeted vaccination of mothers would approximately halve the probability of infants' infection. Vaccination of siblings is less effective in preventing transmission within the household, but may be as effective overall because siblings more often introduce an infection in the household. Vaccination of fathers is expected to be least effective. CONCLUSIONS:: Selective vaccination of persons in households with a young infant may substantially reduce the disease burden of pertussis in infants by reducing transmission within the household. Copyright © 2012 by Lippincott Williams & Wilkins.


Persson S.,Statens Serum Institute | de Boer R.F.,Laboratory for Infectious Diseases | Kooistra-Smid A.M.D.,Laboratory for Infectious Diseases | Olsen K.E.P.,Statens Serum Institute
Diagnostic Microbiology and Infectious Disease | Year: 2011

In this study, 5 different commercial DNA extraction systems were tested on a stool sample collection containing 81 clinical stool specimens that were culture-positive for diarrheagenic Escherichia coli, Campylobacter jejuni, Salmonella enterica, or Clostridium difficile. The purified DNAs were analyzed by polymerase chain reaction (PCR) directed toward the relevant organisms. The results showed that conventional PCR combined with the extraction systems BioRobot EZ1 (Qiagen, Hilden, Germany), Bugs'n Beads (Genpoint, Oslo, Norway), ChargeSwitch (Invitrogen, Paisley, UK), QIAamp Stool Mini Kit (Qiagen), and 2 protocols (generic and Specific A) for EasyMag (BioMérieux, Marcy I'Etoile, France) were able to identify 89%, 62%, 85%, 88%, 85%, and 91%, respectively, of the pathogens originally identified by conventional culture-based methods. When TaqMan PCR was combined with the EasyMag Specific A protocol, 99% of the samples were correctly identified. The results demonstrate that the extraction efficiencies can vary significantly among different extraction systems, careful optimization may have a significant positive effect, and the use of sensitive and specific detection methods like TaqMan PCR is an ideal choice for this type of analysis. © 2011 Elsevier Inc.

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