Gijs Th. J. van Well

Replacing Traditional Diagnostics of Fecal Viral Pathogens by a Comprehensive Panel of Real-Time PCRs

ABSTRACT Molecular DNA-based diagnostics are increasingly being used for diagnosis of viral infections. For enteric viruses, PCR assays have also been developed. The aims of this study were to compile and evaluate a comprehensive panel of PCR assays for diagnosis of viruses causing diarrheal disease and to evaluate its use in a largely pediatric population in a 750-bed university medical center. The PCR panel was designed to include assays for detection of adenovirus, astrovirus, enterovirus, norovirus, parechovirus, rotavirus, and sapovirus. The results of the PCR panel were evaluated in relation to conventional viral diagnostics consisting of viral culture and/or rotavirus and adenovirus rapid antigen tests on samples that were taken for routine diagnostics. Comparing conventional with PCR-based testing, the number of viruses detected increased dramatically from 25 to 106 when PCR assays were used. This increase was due mainly to detection of previously undetected viruses, i.e., astrovirus, norovirus, and sapovirus. In 24% of the samples, norovirus was detected. Also, the lower detection limit of PCR-based adenovirus, enterovirus, parechovirus, and rotavirus diagnostics further increased the detection rate. By focusing on samples from patients with complaints of gastroenteritis, detection of a causative agent was increased from 49% by conventional tests to 97% by molecular diagnostics. However, many samples containing low viral loads were found in patients with complaints other than intestinal complaints. In conclusion, the proposed comprehensive PCR panel with appropriate cutoff values can be used for sensitive, rapid, and clinically relevant diagnosis of gastrointestinal viruses.

Single Nucleotide Polymorphisms in TLR9 Are Highly Associated with Susceptibility to Bacterial Meningitis in Children

BACKGROUND Bacterial meningitis (BM) is a severe infection mainly caused by Streptococcus pneumoniae and Neisseria meningitidis (NM). However, genetically determined susceptibility to develop severe infections by these microorganisms is variable between individuals. Toll-like receptor 9 (TLR9) recognizes bacterial DNA leading to intracellular inflammatory signaling. Single nucleotide polymorphisms (SNPs) within the TLR9 gene are associated with susceptibility to several diseases, no such association with meningitis has been described. METHODS We studied the role of TLR9 SNPs in host defense against BM. Two TLR9 SNPs and 4 TLR9 haplotypes were determined in 472 survivors of BM and compared to 392 healthy controls. RESULTS Carriage of the TLR9+2848-A mutant was significantly decreased in meningococcal meningitis (MM) patients compared with controls (p: .0098, odds ratio [OR]: .6, 95% confidence interval [CI]: .4-.9). TLR9 haplotype I was associated with an increased susceptibility to MM (p: .0237, OR 1.3, 95% CI: 1.0-1.5). In silico analysis shows a very strong immunoinhibitory potential for DNA of NM upon recognition by TLR9 (CpG index of -106.8). CONCLUSIONS We report an association of TLR9 SNPs with susceptibility to BM, specifically MM indicating a protective effect for the TLR9+2848-A allele. We hypothesize that the TLR9+2848-A mutant results in an up-regulation of TLR9 induced immune response compensating the strong inhibitory potential of NM CpG DNA.

Posterior reversible encephalopathy syndrome in paediatric leukaemia

This report describes four patients with acute lymphoblastic leukaemia, suffering from posterior reversible encephalopathy syndrome during the induction period of treatment. A review of the literature on posterior reversible encephalopathy syndrome in paediatric leukaemia is given. The exact mechanism of posterior reversible encephalopathy syndrome is not clear and seems to be multifactorial. Hypertension is likely to play a major role in the development but could be also secondary. All patients in this case series presented after introduction of the new induction protocol for acute lymphoblastic leukaemia. Treatment of hypertension is likely to have a favourable role and posterior reversible encephalopathy syndrome is most often reversible. It is important to consider this diagnosis during the induction phase of leukaemia treatment in the presence of neurological symptoms. The incidence of PRES in the induction scheme should be investigated, in order to optimize the ALL treatment.

Toll-like receptor 9 polymorphisms are associated with severity variables in a cohort of meningococcal meningitis survivors

BackgroundGenetic variation in immune response genes is associated with susceptibility and severity of infectious diseases. Toll-like receptor (TLR) 9 polymorphisms are associated with susceptibility to develop meningococcal meningitis (MM). The aim of this study is to compare genotype distributions of two TLR9 polymorphisms between clinical severity variables in MM survivors.MethodsWe used DNA samples of a cohort of 390 children who survived MM. Next, we determined the genotype frequencies of TLR9 -1237 and TLR9 +2848 polymorphisms and compared these between thirteen clinical variables associated with prognostic factors predicting adverse outcome of bacterial meningitis in children.ResultsThe TLR9 -1237 TC and CC genotypes were associated with a decreased incidence of a positive blood culture for Neisseria (N.) meningitidis (p = 0.014, odds ratio (OR) 0.5. 95% confidence interval (CI) 0.3 – 0.9). The TLR9 +2848 AA mutant was associated with a decreased incidence of a positive blood culture for N. meningitidis (p = 0.017, OR 0.6, 95% CI 0.3 – 0.9). Cerebrospinal fluid (CSF) leukocytes per μL were higher in patients carrying the TLR9 -1237 TC or CC genotypes compared to carriers of the TT wild type (WT) (p = 0.024, medians: 2117, interquartile range (IQR) 4987 versus 955, IQR 3938). CSF blood/glucose ratios were lower in TLR9 -1237 TC or CC carriers than in carriers of the TT WT (p = 0.017, medians: 0.20, IQR 0.4 versus 0.35, IQR 0.5). CSF leukocytes/μL were higher in patients carrying the TLR9 +2848 AA mutant compared to carriers of GG or GA (p = 0.0067, medians: 1907, IQR 5221 versus 891, IQR 3952).ConclusionsWe identified TLR9 genotypes associated with protection against meningococcemia and enhanced local inflammatory responses inside the central nervous system, important steps in MM pathogenesis and defense.

Polymorphisms in Toll-Like Receptors 2, 4, and 9 Are Highly Associated with Hearing Loss in Survivors of Bacterial Meningitis

Genetic variation in innate immune response genes contributes to inter-individual differences in disease manifestation and degree of complications upon infection. We recently described an association of single nucleotide polymorphisms (SNPs) in TLR9 with susceptibility to meningococcal meningitis (MM). In this study, we investigate the association of SNPs in multiple pathogen recognition and immune response genes with clinical features that determine severity and outcome (especially hearing loss) of childhood MM and pneumococcal meningitis (PM). Eleven SNPs in seven genes (TLR2, TLR4, TLR9, NOD1, NOD2, CASP1, and TRAIL) were genotyped in 393 survivors of childhood bacterial meningitis (BM) (327 MM patients and 66 PM patients). Genotype distributions of single SNPs and combination of SNPs were compared between thirteen clinical characteristics associated with severity of BM. After correction for multiple testing, TLR4+896 mutant alleles were highly associated with post-meningitis hearing loss, especially MM (p  = 0.001, OR 4.0 for BM, p  = 0.0004, OR 6.2 for MM). In a multigene analysis, combined carriership of the TLR2+2477 wild type (WT) with TLR4+896 mutant alleles increases the risk of hearing loss (p<0.0001, OR 5.7 in BM and p  = 0.0001, OR 7.6 in MM). Carriage of one or both mutant alleles in TLR4+896 and TLR9 -1237 increases the risk for hearing loss (p  = 0.0006, OR 4.1 in BM). SNPs in immune response genes contribute to differences in clinical severity and outcome of BM. The TLR system seems to play an important role in the immune response to BM and subsequent neuronal damage as well as in cochlear inflammation. Genetic markers may be used for identification of high-risk patients by creating prediction rules for post-meningitis hearing loss and other sequelae, and provide more insight in the complex immune response in the CNS possibly resulting in new therapeutic interventions.

Single nucleotide polymorphisms in pathogen recognition receptor genes are associated with susceptibility to meningococcal meningitis in a pediatric cohort

Bacterial meningitis (BM) is a serious infection of the central nervous system, frequently occurring in childhood and often resulting in hearing loss, learning disabilities, and encephalopathy. Previous studies showed that genetic variation in innate immune response genes affects susceptibility, severity, and outcome of BM. The aim of this study is to describe whether single nucleotide polymorphisms (SNPs) in pathogen recognition gene products are associated with susceptibility to develop BM in single genes analysis as well as SNP combinations. Genotype frequencies of seven SNPs, in five immune response genes encoding for Toll-like receptors (TLRs), nucleotide oligomerization domain (NOD) proteins and caspase-1 (CASP1), in 391 children with meningococcal meningitis (MM) and 82 children with pneumococcal meningitis were compared with a large cohort of 1141 ethnically matched healthy controls. Carriage of TLR4 +896 GG mutant predisposed to susceptibility to develop MM (p = 1.2*10−5, OR  = 9.4, 95% CI  = 3.0–29.2). The NOD2 SNP8 mutant was significantly more frequent in MM patients compared to controls (p = 0.0004, OR  = 12.2, 95% CI  = 2.6–57.8). Combined carriage of TLR2 +2477 and TLR4 +896 mutants was strongly associated with MM (p = 4.2*10−5, OR  = 8.6, 95% CI  = 2.7–27.3). A carrier trait of TLR4 +896 and NOD2 SNP8 mutants was also strongly associated with susceptibility to develop MM (p = 4.2*10−5, OR  = 10.6, 95% CI  = 2.9–38.6). This study associates SNPs in TLR4 and NOD2 with susceptibility to develop MM.

Host Immune Response to Tuberculous Meningitis

BACKGROUND Tuberculous meningitis (TBM) is a severe complication of tuberculosis predominantly affecting young children. Early treatment is vital to prevent morbidity and mortality, emphasizing the importance of early diagnosis. The lack of sensitive methods for early diagnosis is the most common cause of delay. Attempts have been made to develop simplified tests for tuberculosis, but their diagnostic power remains poor. The clinical picture of TBM is mainly driven by the hosts immune response to Mycobacterium tuberculosis; therefore, identification of disease-specific biomarkers may have diagnostic and therapeutic value and improve our understanding of its pathogenesis. METHODS We investigated disease-specific biomarkers of childhood TBM in a cohort of children aged 3 months-13 years with symptoms and signs suggestive of meningitis. Cerebrospinal fluid (CSF) and serum from 56 patients with and 55 patients without TBM were assessed for 28 soluble mediators. RESULTS Unsupervised hierarchical clustering analysis revealed a disease-specific pattern of biomarkers for TBM relative to other types of meningitis. A biomarker-based diagnostic prediction model for childhood TBM based on CSF concentrations of interleukin 13 (cutoff value, 37.26 pg/mL), vascular endothelial growth factor (cutoff value, 42.92 pg/mL), and cathelicidin LL-37 (cutoff value, 3221.01 pg/mL) is presented with a sensitivity of 0.52 and a specificity of 0.95. CONCLUSIONS These data highlight the potential of biosignatures in the hosts CSF for diagnostic applications and for improving our understanding of the pathogenesis of TBM to discover strategies to prevent immunopathological sequelae.

Human perinatal immunity in physiological conditions and during infection

The intrauterine environment was long considered sterile. However, several infectious threats are already present during fetal life. This review focuses on the postnatal immunological consequences of prenatal exposure to microorganisms and related inflammatory stimuli. Both the innate and adaptive immune systems of the fetus and neonate are immature, which makes them highly susceptible to infections. There is good evidence that prenatal infections are a primary cause of preterm births. Additionally, the association between antenatal inflammation and adverse neonatal outcomes has been well established. The lung, gastrointestinal tract, and skin are exposed to amniotic fluid during pregnancy and are probable targets of infection and subsequent inflammation during pregnancy. We found a large number of studies focusing on prenatal infection and the host response. Intrauterine infection and fetal immune responses are well studied, and we describe clinical data on cellular, cytokine, and humoral responses to different microbial challenges. The link to postnatal immunological effects including immune paralysis and/or excessive immune activation, however, turned out to be much more complicated. We found studies relating prenatal infectious or inflammatory hits to well-known neonatal diseases such as respiratory distress syndrome, bronchopulmonary dysplasia, and necrotizing enterocolitis. Despite these data, a direct link between prenatal hits and postnatal immunological outcome could not be undisputedly established. We did however identify several unresolved topics and propose questions for further research.

Salpingitis. A rare cause of acute abdomen in a sexually inactive girl: a case report

Salpingitis is an acute inflammation of the fallopian tubes, most commonly caused by sexually transmitted micro-organisms in adolescent and adult women. It is rarely found in sexually inactive girls and generally the result of a blood-borne or genitourinary infection. In young girls without a history of consensual sexual contact, the possibility of sexual abuse should be considered.Salpingitis usually presents as an acute abdomen. Appendicitis presents with almost the same symptoms as salpingitis. The diagnosis of salpingitis is often delayed until the presumed appendicitis is surgically explored.We describe an 11-year-old girl with salpingitis caused by Streptococcus pneumoniae.

Booklet for Childhood Fever in Out-of-Hours Primary Care: A Cluster-Randomized Controlled Trial

PURPOSE Fever is the most common reason for a child to be taken to a physician, yet the level of unwarranted antibiotic prescribing remains high. We aimed to determine the effect on antibiotic prescribing of providing an illness-focused interactive booklet on fever in children to out-of-hours primary care clinicians. METHODS We conducted a cluster-randomized controlled trial in 20 out-of-hours general practice centers in the Netherlands. Children aged younger than 12 years with fever were included. Family physicians at the 10 intervention sites had access to an illness-focused interactive booklet between November 2015 and June 2016. The primary outcome was antibiotic prescribing during the index consultation. Analysis was performed by fitting 2-level random intercept logistic regression models. RESULTS The trial took place among 3,518 family physicians and 25,355 children. The booklet was used in 28.5% of 11,945 consultations in the intervention group. Compared with usual care, access to the booklet did not significantly alter antibiotic prescribing during the index consultation (odds ratio = 0.90; 95% CI, 0.79-1.02; prescription rate, 23.5% vs 25.2%; intracluster correlation coefficient = 0.005). In contrast, use of the booklet significantly reduced antibiotic prescribing (odds ratio = 0.83; 95% CI, 0.74-0.94; prescription rate, 21.9% vs 25.2%; intracluster correlation coefficient = 0.002). Children managed by family physicians with access to the booklet were less likely to receive any drug prescription, and parents in the booklet group showed a reduced intention to consult again for similar illnesses. CONCLUSIONS Benefit of an illness-focused interactive booklet in improving outcomes of childhood fever in out-of-hours primary care was largely restricted to the cases in which family physicians actually used the booklet. Insight into reasons for use and nonuse may inform future interventions of this type.