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Managing neonatal sepsis is challenging due to nonspecific clinical signs, hematological markers with poor accuracy, and a lengthy turnaround time for the identification of microorganisms. Delaying the initiation of antibiotics in truly infected infants can lead to severe morbidity and mortality. Therefore, decisions regarding empiric antibiotic treatment are risk stratified, which exposes many uninfected infants to antibiotics. This causes gut microbiota perturbation, unnecessary hospital admissions, and the generation of multi-resistant organisms. High-speed diagnostic assays could expedite discontinuation or avert the initiation of antibiotics in uninfected infants. This study will evaluate the diagnostic performance of molecular culture (MC), a rapid broad-range PCR-based bacterial profiling technique, for diagnosing neonatal sepsis in infants below 90 days old. A multi-center prospective observational cohort study will include infants evaluated for early and late-onset sepsis. Routine evaluation for suspected sepsis includes microbiological cultures of blood. Additionally, blood for MC will be collected. For early-onset sepsis, umbilical cord blood may be used alternatively. Primary outcome is the agreement between MC and conventional blood culture results. Secondary outcome is the agreement of both assays with clinical sepsis using four different, commonly used definitions. Faster diagnostic pathways for sepsis may reduce antibiotic exposure time. Broad-range molecular assays may identify pathogens undetectable by conventional methods. Employment of umbilical cord blood samples for early-onset sepsis diagnosis can resolve challenges in collecting adequate blood volume and could further expedite treatment decisions. [ABSTRACT FROM AUTHOR]

The urogenital microbiota is increasingly gaining recognition as a significant contributor to reproductive health. Recent studies suggest that microbiota can serve as predictors for fertility treatment outcomes. Our objective was to investigate the degree of similarity in microbial composition between patient-collected urine and vaginal samples in a subfertile population. We enrolled women of reproductive age (20–44 years) diagnosed with subfertility and requiring in vitro fertilization (IVF) or IVF with intracytoplasmic sperm injection (IVF-ICSI) treatment. They self-collected both mid-stream urine samples and vaginal swabs before commencing the IVF or IVF-ICSI procedure. All samples were analysed using the intergenic spacer profiling (IS-pro) technique, a rapid clinical microbiota analysis tool. The main outcome measures were the degree of similarity of microbial composition between the two different, but simultaneously collected, samples. Our findings revealed a high correlation (R squared of 0.78) in microbiota profiles between paired urine and vaginal samples from individual patients. Nevertheless, the urinary microbiota profiles contained fewer species compared to the vaginal microbiota, resulting in minor but distinguishable differences. Furthermore, different subfertility diagnoses appeared to be associated with differences in microbial profiles. A noteworthy observation was the exclusive presence of Escherichia coli (E. coli) in both samples of women diagnosed with male factor subfertility. In conclusion, since urinary microbiota profiles seem to represent a diluted version of the vaginal microbiota, vaginal microbiome sampling to predict fertility treatment outcome seems preferable. To enhance the success of fertility treatments, further research is needed to gain deeper insights into a putative causal role of microbiota in the mechanisms of subfertility. [ABSTRACT FROM AUTHOR]

The evolutionarily conserved protein Omp85 is required for outer membrane protein (OMP) assembly in gram-negative bacteria and in mitochondria. Its Escherichia coli homolog, designated BamA, functions with four accessory lipoproteins, BamB, BamC, BamD, and BamE, together forming the [beta]-barrel assembly machinery (Bam). Here, we addressed the composition of this machinery and the function of its components in Neisseria meningitidis, a model organism for outer membrane biogenesis studies. Analysis of genome sequences revealed homologs of BamC, BamD (previously described as ComL), and BamE and a second BamE homolog, MIp. No homolog of BamB was found. As in E. coli, ComL/BamD appeared essential for viability and for OMP assembly, and it could not be replaced by its E. coli homolog. BamE was not essential but was found to contribute to the efficiency of OMP assembly and to the maintenance of OM integrity. A bamC mutant showed only marginal OMP assembly defects, but the impossibility of creating a bamC bamE double mutant further indicated the function of BamC in OMP assembly. An mlp mutant was unaffected in OMP assembly. The results of copurification assays demonstrated the association of BamC, ComL, and BamE with Omp85. Semi-native gel electrophoresis identified the RmpM protein as an additional component of the Omp85 complex, which was confirmed in copurification assays. RmpM was not required for OMP folding but stabilized OMP complexes. Thus, the Barn complex in N. meningitidis consists of Omp85/BamA plus RmpM, BamC, ComL/BamD, and BamE, of which ComL/BamD and BamE appear to be the most important accessory components for OMP assembly. doi: 10.1128/JB.00737-09

The outer membranes of Gram-negative bacteria, mitochondria, and chloroplasts harbor [beta]-barrel proteins. The signals that allow precursors of such proteins to be targeted to mitochondria were not characterized so far. To better understand the mechanism by which [beta]-barrel precursor proteins are recognized and sorted within eukaryotic cells, we expressed the bacterial [beta]-barrel proteins PhoE, OmpA, Omp85, and OmpC in Saccharomyces cerevisiae and demonstrated that they were imported into mitochondria. A detailed investigation of the import pathway of PhoE revealed that it is shared with mitochondrial [beta]-barrel proteins. PhoE interacts initially with surface import receptors, and its further sorting depends on components of the TOB/SAM complex. The bacterial Omp85 and PhoE integrated into the mitochondrial outer membrane as native-like oligomers. For the latter protein this assembly depended on the C-terminal Phe residue, which is important also for the correct assembly of PhoE into the bacterial outer membrane. Collectively, it appears that mitochondrial [beta]-barrel proteins have not evolved eukaryotic-specific signals to ensure their import into mitochondria. Furthermore, the signal for assembly of [beta]-barrel proteins into the bacterial outer membrane is functional in mitochondria. outer membrane | PhoE | protein import | TOB complex | TOM complex

Model organisms developed for components of outer membrane synthesized in cytoplasm to be sent across the inner membrane through the periplasm for assembling in correct membrane is studied.

After transport across the cytoplasmic membrane, bacterial outer membrane proteins are assembled into the outer membrane, Meningococcal Omp85 is a highly conserved protein in Gram-negative bacteria, and its homolog Toc75 is a component of the chloroplast protein-import machinery. Omp85 appeared to be essential for viability, and unassembled forms of various outer membrane proteins accumulated upon Omp85 depletion. Immunofluorescence microscopy revealed decreased surface exposure of outer membrane proteins, which was particularly apparent at the cell-division planes. Thus, Omp85 is likely to play a role in outer membrane protein assembly., The cell envelope of Gram-negative bacteria consists of an outer membrane (OM) and an inner membrane (IM), separated by the periplasm. The IM is a phospholipid bilayer, whereas the OM [...]