Coagulase-negative staphylococci are associated to the mild inflammatory pattern of healthcare-associated meningitis: a retrospective study.

The epidemiology of healthcare-associated meningitis (HAM) is dominated by commensal bacteria from the skin, as coagulase-negative staphylococci (CoNS). We hypothesized that the pauci-symptomatic and mild inflammatory patterns of HAM are related to the low pathogenic state of CoNS. Our aim was to describe clinical and biological features of CoNS HAM, compared to other HAM. All consecutive patients with HAM admitted in our hospital were retrospectively included from 2007 to 2014. HAM due to CoNS were compared to HAM caused by other bacteria (controls) for clinical and laboratory patterns. Seventy-one cases of HAM were included, comprising 18 CoNS and 53 controls. Patients were not different in terms of baseline characteristics. CoNS HAM occurred later after the last surgery than controls (17 vs. 12 days, p = 0.029) and had higher Glasgow Coma Scale (GCS) score (14 vs. 13, p = 0.038). Cerebrospinal fluid (CSF) analysis revealed a lower pleocytosis (25 vs. 1340/mm3, p < 0.001), a higher glucose level (3.75 vs. 0.8 mmol/L, p < 0.001), and a lower protein level (744 vs. 1751 mg/L, p < 0.001) in the CoNS group than in the control group, respectively. HAM due to CoNS was significantly less symptomatic and less inflammatory than HAM due to other bacteria.

Characterisation of PfSec61, a Plasmodium falciparum homologue of a component of the translocation machinery at the endoplasmic reticulum membrane of eukaryotic cells.

Plasmodium falciparum secretes several proteins that cause changes in the erythrocyte membrane enabling it to survive within red blood cells. Little is known of the mechanisms involved in the secretion and targeting of parasite polypeptides to the various cell compartments. The P. falciparum gene homologous to the mammalian Sec61alpha, gene, which encodes a component of the translocation pore in the endoplasmic reticulum of eukaryotic cells, was characterised to investigate the translocation process in the parasite. PfSec61 is present as a unique copy in the parasite genome and was mapped to chromosome 13. It encodes a 40 kDa polypeptide, as shown by immunoblotting and immunoprecipitation of [35S]methionine metabolically-labelled parasite extracts. The deduced amino acid sequence of PfSec61 is 87% similar to the mammalian polypeptide, and the two proteins give similar hydropathy plots. These results strongly suggest that PfSec61 has the same topological orientation and functional role as Sec61alpha. Anti-PfSec61 antibodies were used to investigate the cellular location and kinetics of expression of the polypeptide in the parasite. Immunofluorescence confocal microscopy showed that PfSec61 was located in the parasite cytoplasm, close to the nucleus, in a position consistent with its being in the endoplasmic reticulum.

The transport of the histidine-rich protein I from Plasmodium falciparum is insensitive to brefeldin A.

During its intraerythrocytic development, Plasmodium falciparum synthesizes several proteins that are exported beyond its membrane. Some of these secreted antigens are involved in the formation of protuberances or knobs, a major virulence factor, at the erythrocyte membrane. Various secreted malarial polypeptides, the transport of which is sensitive to brefeldin A, are translocated in vitro into dog pancreatic microsomes. We present evidence that the histidine-rich protein I (PfHRPI) is secreted by the parasite via a novel pathway, independent of the ER/Golgi apparatus. The secretion of PfHRPI was not blocked by incubation of parasite cultures at 15 degrees C and 20 degrees C or 37 degrees C in the presence of brefeldin A. PfHRPI was not translocated into microsomes in an in vitro translation-translocation cell-free system. Unlike other polypeptides from eukaryotic cells that bypass the ER/Golgi pathway and do not have a signal peptide, PfHRPI has an atypical signal sequence consisting of 21 amino acids, including eight positively charged residues followed by 11 hydrophobic residues. We also found that the unusually charged PfHRPI signal sequence diverts Exp-1, which is usually exported, away from the translocation machinery of microsomal membranes.

Quantitative measurement of zacopride in human plasma and urine by combined gas chromatography/negative ion chemical ionization mass spectrometry.

A highly sensitive and specific assay was developed for routine analysis of zacopride at the femtomole level in human plasma and urine. Zacopride and the deuterated internal standard [(2H3)zacopride] were measured by gas chromatography/negative ion chemical ionization mass spectrometry with methane as the reagent gas. A multiple-step liquid-liquid extraction procedure was used to isolate the two compounds of interest from complex biological matrices. Zacopride was converted to the fluorinated derivative with pentafluoropropionic anhydride. The mass spectrometer was tuned to monitor the very intense [M-HF]- ion at m/z 435 which was generated into the ion source by a dissociative capture process. This assay was performed with 1 ml of plasma or 0.2 ml of urine, and the quantification limit of the method was calculated as 10 pg ml-1 using a suitable statistical test. The very low relative standard deviation and mean percentage error values calculated during the within-day or between-day repeatability assays have clearly demonstrated the ruggedness of the technique for the routine quantitative measurement of zacopride in plasma and urine. Some preliminary results on the pharmacokinetics of this potent drug are presented to illustrate the applicability of this new powerful gas chromatographic/mass spectrometric method.