Burkholderia cenocepacia (formerly Burkholderia cepacia complex genomovar III) causes chronic lung infections in patients with cystic fibrosis. In this work, we used a modified signature-tagged mutagenesis (STM) strategy for the isolation of B. cenocepacia mutants that cannot survive in vivo. Thirty-seven specialized plasposons, each carrying a unique oligonucleotide tag signature, were constructed and used to examine the survival of 2,627 B. cenocepacia transposon mutants, arranged in pools of 37 unique mutants, after a 10-day lung infection in rats by using the agar bead model. The recovered mutants were screened by real-time PCR, resulting in the identification of 260 mutants which presumably did not survive within the lungs. These mutants were repooled into smaller pools, and the infections were repeated. After a second screen, we isolated 102 mutants unable to survive in the rat model. The location of the transposon in each of these mutants was mapped within the B. cenocepacia chromosomes. We identified mutations in genes involved in cellular metabolism, global regulation, DNA replication and repair, and those encoding bacterial surface structures, including transmembrane proteins and cell surface polysaccharides. Also, we found 18 genes of unknown function, which are conserved in other bacteria. A subset of 12 representative mutants that were individually examined using the rat model in competition with the wild-type strain displayed reduced survival, confirming the predictive value of our STM screen. This study provides a blueprint to investigate at the molecular level the basis for survival and persistence of B. cenocepacia within the airways.

West Nile virus (WNV) infection causes neurological disease at all levels of the neural axis, accompanied by neuroinflammation and neuronal loss, although the underlying mechanisms remain uncertain. Given the substantial activation of neuroinflammatory pathways observed in WNV infection, we hypothesized that WNV-mediated neuroinflammation and cell death occurred through WNV infection of both glia and neurons, which was driven in part by WNV capsid protein expression. Analysis of autopsied neural tissues from humans with WNV encephalomyelitis (WNVE) revealed WNV infection of both neurons and glia. Upregulation of proinflammatory genes, CXCL10, interleukin-1␤, and indolamine-2,3-deoxygenase with concurrent suppression of the protective astrocytespecific endoplasmic reticulum stress sensor gene, OASIS (for old astrocyte specifically induced substance), was evident in WNVE patients compared to non-WNVE controls. These findings were supported by increased ex vivo expression of these proinflammatory genes in glia infected by WNV-NY99. WNV infection caused endoplasmic reticulum stress gene induction and apoptosis in neurons but did not affect glial viability. WNV-infected astrocytic cells secreted cytotoxic factors, which caused neuronal apoptosis. The expression of the WNV-NY99 capsid protein in neurons and glia by a Sindbis virus-derived vector (SINrep5-WNVc) caused neuronal death and the release of neurotoxic factors by infected astrocytes, coupled with proinflammatory gene induction and suppression of OASIS. Striatal implantation of SINrep5-WNV C induced neuroinflammation in rats, together with the induction of CXCL10 and diminished OASIS expression, compared to controls. Moreover, magnetic resonance neuroimaging showed edema and tissue injury in the vicinity of the SINrep5-WNVc implantation site compared to controls, which was complemented by neurobehavioral abnormalities in the SINrep5-WNVc-implanted animals. These studies underscore the important interactions between the WNV capsid protein and neuroinflammation in the pathogenesis of WNV-induced neurological disorders.In North America, widespread West Nile virus (WNV) infection was first recognized in 1999 during an outbreak of viral encephalitis in New York City (32). Infection by WNV causes a spectrum of neurological disorders and ensuing death in a subset of infected individuals (24,26). WNV belongs to the flavivirus family (reviewed in references 11, 14, and 34), which are enveloped viruses with a genome consisting of one 10-to 11-kb single-stranded RNA molecule of positive-strand mRNA polarity. WNV genomic RNA contains one large open reading frame, which is translated into a single polypeptide and cleaved by viral and cellular proteases into three structural proteins and several nonstructural (NS) proteins (11, 34). The WNV structural proteins include the capsid (C) protein, the small transmembrane protein (M and its precursor preM), and the surface or envelope glycoprotein (E), which are all involved in pathogenesis. It is clear that infection of the centr...

Burkholderia cenocepacia is an opportunistic bacterium that infects patients with cystic fibrosis. B. cenocepacia strains J2315, K56-2, C5424, and BC7 belong to the ET12 epidemic clone, which is transmissible among patients. We have previously shown that transposon mutants with insertions within the O antigen cluster of strain K56-2 are attenuated for survival in a rat model of lung infection. From the genomic DNA sequence of the O antigen-deficient strain J2315, we have identified an O antigen lipopolysaccharide (LPS) biosynthesis gene cluster that has an IS402 interrupting a predicted glycosyltransferase gene. A comparison with the other clonal isolates revealed that only strain K56-2, which produced O antigen and displayed serum resistance, lacked the insertion element inserted within the putative glycosyltransferase gene. We cloned the uninterrupted gene and additional flanking sequences from K56-2 and conjugated this plasmid into strains J2315, C5424, and BC7. All the exconjugants recovered the ability to form LPS O antigen. We also determined that the structure of the strain K56-2 O antigen repeat, which was absent from the LPS of strain J2315, consisted of a trisaccharide unit made of rhamnose and two N-acetylgalactosamine residues. The complexity of the gene organization of the K56-2 O antigen cluster was also investigated by reverse transcription-PCR, revealing several transcriptional units, one of which also contains genes involved in lipid A-core oligosaccharide biosynthesis.

Kennedy terminal ulcers, a subset of pressure injuries, are associated with the dying process. This scoping review aimed to identify and map the published literature on Kennedy terminal ulcers in terms of its definition, prevalence, assessment, treatment, management, health care costs, and quality of life for patients in all health care settings. Using the Arksey and O'Malley scoping review framework, we systematically searched the Cochrane Library, CINAHL, EMBASE, MEDLINE, and ProQuest databases and 5 guideline repositories between 1983 and 2018. The following search terms were used: Kennedy ulcers, Kennedy terminal ulcers, terminal ulcer, skin failure, and Skin Changes at Life's End. Data were extracted using a purposely developed data collection tool. Initial searches yielded 2997 sources, with 32 included in this review. Most Kennedy terminal ulcer literature was published by nurses in the United States. Kennedy terminal ulcer prevalence data are limited, with no validated assessment tools available. Kennedy terminal ulcers may be misclassified as pressure injuries, potentially resulting in financial penalties to the institution. This scoping review revealed significant knowledge and clinical practice gaps in patient assessment, management, and treatment of Kennedy terminal ulcers. Timely patient education may help them to make informed care and quality end-of-life decisions. Further research is needed to inform clinical practice to improve patient care.