Campylobacter jejuni subdural hygroma infection in a 2-year old boy: case report and a brief literature review.

BACKGROUND: Campylobacter jejuni is a common cause of acute gastroenteritis, but central nervous system infections are rare manifestations of Campylobacter infection. Therefore, C. jejuni trauma-related subdural hygroma infection in children is poorly described in the literature. CASE PRESENTATION: We described a 2-year old boy with lobar holoprosencephaly presenting with subdural hygroma following head trauma. C. jejuni infection was confirmed from a subdural hygroma sample by culture as well as by DNA sequencing of a broad range 16S rDNA PCR product. Cerebrospinal fluid from the ventriculoperitoneal shunt remained sterile. Combined neurosurgical and antimicrobial treatment led to complete recovery. Review of the literature showed that the most common manifestation of Campylobacter central nervous system infection is meningitis, mostly in neonates, and subdural hygroma infection was described for only one case. CONCLUSIONS: Subdural hygroma infection caused by C. jejuni is a rare clinical condition in children. Molecular methods represent an important tool for the detection of rare or unexpected pathogens. No standard recommendations for antimicrobial treatment of C. jejuni subdural space infection in children are available, but meropenem treatment combined with surgery seems to be an effective approach.

Healthy Siblings of Children With Crohn's Disease Exhibit More Rapid Changes in Microbiota Composition as a Response to Exclusive Enteral Nutrition.

BACKGROUND: The aim of this study was to determine the impact of exclusive enteral nutrition (EEN) on the microbiota composition of the newly diagnosed Crohn's disease (CD) patients and to determine the effect of EEN received for 2 days in siblings of patients with CD. METHODS: Newly diagnosed pediatric CD patients (n = 17) and unaffected healthy siblings (n = 10) participated in the study. In CD patients, stool samples were collected at 3 time points: prior to therapy introduction, the second day of EEN therapy, and the last day of EEN therapy. In healthy siblings, stool samples were collected before the introduction of EEN and the second day of EEN. Molecular approach targeting 16S ribosomal RNA was used for analyzing the gut microbiota of participants' stool samples. RESULTS: There was no significant difference in microbial diversity between children with CD and healthy siblings before EEN (P = .127 for HhaI digestion; P = .604 for MspI digestion) as opposed to the second day of EEN (P = .006 HhaI digestion; P = .023 MspI digestion). In healthy controls, significant changes in microbiota composition were apparent by the second day of EEN, contrary to children with CD, in whom similar changes in microbiota composition were apparent on the last day of EEN. CONCLUSION: EEN leads to significant microbiota changes in both healthy children and children with CD. Changes in microbiota composition occur more rapidly in healthy children, whereas in children with CD, significant changes were detected at the end of EEN.

Preprotein recognition by the Toc complex.

The Toc core complex consists of the pore-forming Toc75 and the GTPases Toc159 and Toc34. We confirm that the receptor form of Toc159 is integrated into the membrane. The association of Toc34 to Toc75/Toc159 is GTP dependent and enhanced by preprotein interaction. The N-terminal half of the pSSU transit peptide interacts with high affinity with Toc159, whereas the C-terminal part stimulates its GTP hydrolysis. The phosphorylated C-terminal peptide of pSSU interacts strongly with Toc34 and therefore inhibits binding and translocation of pSSU into Toc proteoliposomes. In contrast, Toc159 recognises only the dephosphorylated forms. The N-terminal part of the pSSU presequence does not influence binding to the Toc complex, but is able to block import into proteoliposomes through its interaction with Toc159. We developed a model of differential presequence recognition by Toc34 and Toc159.

The chloroplast import receptor Toc34 functions as preprotein-regulated GTPase.

Toc34 is a protein of the chloroplast outer envelope membrane that acts as receptor for preproteins containing a transit sequence. The recognition of preproteins by Toc34 is regulated by GTP binding and phosphorylation. The phosphorylation site of Toc34 is located at serine 113, close to the postulated triphosphate binding site. This can explain the down-regulation of Toc34 by phosphorylation, resulting in the loss of GTP binding. Vice versa, GTP but not GDP binding of Toc34 influences the phosphorylation. The nucleotide specificity of Toc34 is not only determined by the classical nucleotide binding domains but by a non-typical region at the N-terminus of the protein. As a result, the GTP binding properties are unusual, since the triphosphate moiety of GTP is bound with higher affinity than the purine base. Purified Toc34 hydrolyses GTP at a low rate, which could regulate the receptor function. The rate of hydrolysis is greatly stimulated by a precursor protein.