Genetic loci of Staphylococcus aureus associated with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides

The proteinase 3 (PR3)-positive anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) granulomatosis with polyangiitis (GPA) has been associated with chronic nasal S. aureus carriage, which is a risk factor for disease relapse. The present study was aimed at comparing the genetic make-up of S. aureus isolates from PR3-ANCA-positive GPA patients with that of isolates from patients suffering from myeloperoxidase (MPO)-ANCA-positive AAV, and isolates from healthy controls. Based on a DNA microarray-based approach, we show that not only PR3-ANCA-positive GPA patients, but also MPO-ANCA-positive AAV patients mainly carried S. aureus types that are prevalent in the general population. Nonetheless, our data suggests that MPO-ANCA-associated S. aureus isolates may be distinct from healthy control- and PR3-ANCA-associated isolates. Furthermore, several genetic loci of S. aureus are associated with either PR3-ANCA- or MPO-ANCA-positive AAV, indicating a possible role for pore-forming toxins, such as leukocidins, in PR3-ANCA-positive GPA. Contrary to previous studies, no association between AAV and superantigens was detected. Our findings also show that a lowered humoral immune response to S. aureus is common for PR3-ANCA- and MPO-ANCA-positive AAV. Altogether, our observations imply that the presence or absence of particular virulence genes of S. aureus isolates from AAV patients contributes to disease progression and/or relapse

National laboratory-based surveillance system for antimicrobial resistance: a successful tool to support the control of antimicrobial resistance in the Netherlands

An important cornerstone in the control of antimicrobial resistance (AMR) is a well-designed quantitative system for the surveillance of spread and temporal trends in AMR. Since 2008, the Dutch national AMR surveillance system, based on routine data from medical microbiological laboratories (MMLs), has developed into a successful tool to support the control of AMR in the Netherlands. It provides background information for policy making in public health and healthcare services, supports development of empirical antibiotic therapy guidelines and facilitates in-depth research. In addition, participation of the MMLs in the national AMR surveillance network has contributed to sharing of knowledge and quality improvement. A future improvement will be the implementation of a new semantic standard together with standardised data transfer, which will reduce errors in data handling and enable a more real-time surveillance. Furthermore, the

Novel compound heterozygous TULP1 mutations in a family with severe early-onset retinitis pigmentosa.

Contains fulltext : 53145.pdf (publisher's version ) (Closed access)OBJECTIVE: To describe the clinical characteristics and determine the genetic defect in a Surinamese family with autosomal recessive retinitis pigmentosa. METHODS: Family members underwent blood sampling and ophthalmologic examinations. After exclusion of all known mutations in all genes involved in autosomal recessive retinitis pigmentosa, a genome-wide linkage scan was performed using 11,555 single-nucleotide polymorphisms spread throughout the genome. Mutation analysis of the TULP1 gene was performed by direct sequencing. RESULTS: All affected family members had a severe retinal dystrophy with a history of nystagmus, low visual acuity, and nyctalopia since infancy. The scotopic and photopic responses were nonrecordable on electroretinography. A genome-wide scan suggested linkage to the chromosomal region containing the TULP1 gene. Mutation analysis of TULP1 identified novel compound heterozygous mutations (p.Arg482Trp and p.Leu504fsX140) in all affected family members. CONCLUSIONS: The affected members of the Surinamese family have a severe early-onset form of autosomal recessive retinitis pigmentosa, which is caused by compound heterozygous mutations in the TULP1 gene. Clinical Relevance Clinical and molecular genetic characterization of autosomal recessive retinitis pigmentosa may help to provide a more accurate prognosis in individual patients. This study confirms that TULP1 mutations cause a severe early-onset form of autosomal recessive retinitis pigmentosa

Characterization of the Crumbs homolog 2 (CRB2) gene and analysis of its role in retinitis pigmentosa and Leber congenital amaurosis.

Contains fulltext : 48627.pdf (publisher's version ) (Open Access)PURPOSE: Mutations in the Crumbs homolog 1 (CRB1) gene cause autosomal recessive retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA). Database searches reveal two other Crumbs homologs on chromosomes 9q33.3 and 19p13.3. The purpose of this study was to characterize the Crumbs homolog 2 (CRB2) gene on 9q33.3, to analyze its expression pattern, and to determine whether mutations in CRB2 are associated with RP and LCA. METHODS: The CRB2 mRNA and its expression pattern in human tissues were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The cellular expression of Crb2 in the mouse eye was determined by mRNA in situ hybridizations. The open reading frame and splice junctions of CRB2 were analyzed for mutations by single-strand conformation analysis and direct nucleotide sequencing in 85 RP patients and 79 LCA patients. RESULTS: The CRB2 gene consists of 13 exons and encodes a 1285 amino acid transmembrane protein. CRB2 is mainly expressed in retina, brain, and kidney. In mouse retina Crb2 expression was detected in all cell layers. Mutation analysis of the CRB2 gene revealed 11 sequence variants leading to an amino acid substitution. Three of them were not identified in control individuals and affect conserved amino acid residues. However, the patients that carry these sequence variants do not have a second sequence variant on the other allele, excluding autosomal recessive inheritance of CRB2 sequence variants as a cause of their disease. CONCLUSIONS: This study shows that CRB2 sequence variants are not a common cause of autosomal recessive RP and LCA. It is possible that a more complex clinical phenotype is associated with the loss or altered function of CRB2 in humans due to its expression in tissues other than the retina

FERM protein EPB41L5 is a novel member of the mammalian CRB-MPP5 polarity complex

Cell polarity is induced and maintained by separation of the apical and basolateral domains through specialized cell-cell junctions. The Crumbs protein and its binding partners are involved in formation and stabilization of adherens junctions. In this study, we describe a novel component of the mammalian Crumbs complex, the FERM domain protein EPB41L5, which associates with the intracellular domains of all three Crumbs homologs through its FERM domain. Surprisingly, the same FERM domain is involved in binding to the HOOK domain of MPP5/PALS1, a previously identified interactor of Crumbs. Co-expression and co-localization studies suggested that in several epithelial derived tissues Epb4.1l5 interacts with at least one Crumbs homolog, and with Mpp5. Although at early embryonic stages Epb4.1l5 is found at the basolateral membrane compartment, in adult tissues it co-localizes at the apical domain with Crumbs proteins and Mpp5. Overexpression of Epb4.1l5 in polarized MDCK cells affects tightness of cell junctions and results in disorganization of the tight junction markers ZO-1 and PATJ. Our results emphasize the importance of a conserved Crumbs-MPP5-EPB41L5 polarity complex in mammals