The StkSR Two-Component System Influences Colistin Resistance in .

is an opportunistic human pathogen responsible for numerous severe nosocomial infections. Genome analysis on the clinical isolate 04117201 revealed the presence of 13 two-component signal transduction systems (TCS). Of these, we examined the putative TCS named here as StkSR.

Resistance to pentamidine is mediated by AdeAB, regulated by AdeRS, and influenced by growth conditions in Acinetobacter baumannii ATCC 17978.

In recent years, effective treatment of infections caused by Acinetobacter baumannii has become challenging due to the ability of the bacterium to acquire or up-regulate antimicrobial resistance determinants. Two component signal transduction systems are known to regulate expression of virulence factors including multidrug efflux pumps. Here, we investigated the role of the AdeRS two component signal transduction system in regulating the AdeAB efflux system, determined whether AdeA and/or AdeB can individually confer antimicrobial resistance, and explored the interplay between pentamidine resistance and growth conditions in A.

The Merits of Malaria Diagnostics during an Ebola Virus Disease Outbreak.

Malaria is a major public health concern in the countries affected by the Ebola virus disease epidemic in West Africa. We determined the feasibility of using molecular malaria diagnostics during an Ebola virus disease outbreak and report the incidence of Plasmodium spp. parasitemia in persons with suspected Ebola virus infection.

Delivery of an Ebola Virus-Positive Stillborn Infant in a Rural Community Health Center, Sierra Leone, 2015.

We report the case of an Ebola virus (EBOV) RNA-negative pregnant woman who delivered an EBOV RNA-positive stillborn infant at a community health center in rural Sierra Leone, 1 month after the mother's last possible exposure. The mother was later found to be immunoglobulins M and G positive indicating previous infection. The apparent absence of Ebola symptoms and not recognizing that the woman had previous contact with an Ebola patient led health workers performing the delivery to wear only minimal personal protection, potentially exposing them to a high risk of EBOV infection.

Identification of genes essential for pellicle formation in Acinetobacter baumannii.

Background: Acinetobacter baumannii is an opportunistic pathogen, which has the ability to persist in the clinical environment, causing acute and chronic infections. A possible mechanism contributing to survival of A. baumannii is its ability to form a biofilm-like structure at the air/liquid interface, known as a pellicle.

A new antibiotic with potent activity targets MscL.

The growing problem of antibiotic-resistant bacteria is a major threat to human health. Paradoxically, new antibiotic discovery is declining, with most of the recently approved antibiotics corresponding to new uses for old antibiotics or structurally similar derivatives of known antibiotics. We used an in silico approach to design a new class of nontoxic antimicrobials for the bacteria-specific mechanosensitive ion channel of large conductance, MscL.

Clonal expansion of hepatocytes with a selective advantage occurs during all stages of chronic hepatitis B virus infection.

Hepatocyte clone size was measured in liver samples of 21 patients in various stages of chronic hepatitis B virus (HBV) infection and from 21 to 76 years of age. Hepatocyte clones containing unique virus-cell DNA junctions formed by the integration of HBV DNA were detected using inverse nested PCR. The maximum hepatocyte clone size tended to increase with age, although there was considerable patient-to-patient variation in each age group.

Aqueous based synthesis of antimicrobial-decorated graphene.

Ramizol® (1,3,5-tris[(1E)-2'-(4'-benzoic acid)vinyl]benzene) is a potent amphiphilic anti-microbial agent. It is essentially a planar molecule and can interact with the surface of graphene via extended π-π interactions. Herein we demonstrate the utility of Ramizol® in potentially acting as a molecular 'wedge' to exfoliate graphene and stabilise it in water.

Comparative analysis of surface-exposed virulence factors of Acinetobacter baumannii.

Background: Acinetobacter baumannii is a significant hospital pathogen, particularly due to the dissemination of highly multidrug resistant isolates. Genome data have revealed that A. baumannii is highly genetically diverse, which correlates with major variations seen at the phenotypic level.

H-NS plays a role in expression of Acinetobacter baumannii virulence features.

Acinetobacter baumannii has become a major problem in the clinical setting with the prevalence of infections caused by multidrug-resistant strains on the increase. Nevertheless, only a limited number of molecular mechanisms involved in the success of A. baumannii as a human pathogen have been described.

Severe hemorrhagic fever in strain 13/N guinea pigs infected with Lujo virus.

Lujo virus (LUJV) is a novel member of the Arenaviridae family that was first identified in 2008 after an outbreak of severe hemorrhagic fever (HF). In what was a small but rapidly progressing outbreak, this previously unknown virus was transmitted from the critically ill index patient to 4 attending healthcare workers. Four persons died during this outbreak, for a total case fatality of 80% (4/5).

Contribution of a genomic accessory region encoding a putative cellobiose phosphotransferase system to virulence of Streptococcus pneumoniae.

Streptococcus pneumoniae (the pneumococcus) is a formidable human pathogen, responsible for massive global morbidity and mortality. The ability to utilize carbohydrates in a variety of host niches appears to be integral to pneumococcal pathogenesis. In this study we investigated a genomic island, which includes a ROK family protein, a putative cellobiose phosphotransferase system (PTS) and a putative sulfatase.

Adherence and motility characteristics of clinical Acinetobacter baumannii isolates.

Acinetobacter baumannii continues to be a major health problem especially in hospital settings. Herein, features that may play a role in persistence and disease potential were investigated in a collection of clinical A. baumannii strains from Australia.

Using next generation sequencing to identify yellow fever virus in Uganda.

In October and November 2010, hospitals in northern Uganda reported patients with suspected hemorrhagic fevers. Initial tests for Ebola viruses, Marburg virus, Rift Valley fever virus, and Crimean Congo hemorrhagic fever virus were negative. Unbiased PCR amplification of total RNA extracted directly from patient sera and next generation sequencing resulted in detection of yellow fever virus and generation of 98% of the virus genome sequence.

Contribution of serotype and genetic background to virulence of serotype 3 and serogroup 11 pneumococcal isolates.

The capsular serotype has long been associated with the virulence of Streptococcus pneumoniae. Here we present an in-depth study of phenotypic and genetic differences between serotype 3 and serogroup 11 S. pneumoniae clinical isolates from both the general and indigenous populations of Australia.

A variable region within the genome of Streptococcus pneumoniae contributes to strain-strain variation in virulence.

The bacterial factors responsible for the variation in invasive potential between different clones and serotypes of Streptococcus pneumoniae are largely unknown. Therefore, the isolation of rare serotype 1 carriage strains in Indigenous Australian communities provided a unique opportunity to compare the genomes of non-invasive and invasive isolates of the same serotype in order to identify such factors. The human virulence status of non-invasive, intermediately virulent and highly virulent serotype 1 isolates was reflected in mice and showed that whilst both human non-invasive and highly virulent isolates were able to colonize the murine nasopharynx equally, only the human highly virulent isolates were able to invade and survive in the murine lungs and blood.

The conformation and function of a multimodular glycogen-degrading pneumococcal virulence factor.

SpuA is a large multimodular cell wall-attached enzyme involved in the degradation of glycogen by the pathogenic bacterium Streptococcus pneumoniae. The deletion of the gene encoding SpuA from the bacterium resulted in a strain with reduced competitiveness in a mouse model of virulence relative to the parent strain, linking the degradation of host-glycogen to the virulence of the bacterium. Through the combined use of X-ray crystallography, small-angle X-ray scattering, and inhibitor binding, the molecular features involved in substrate recognition by this complex protein are revealed.

Identification of N-glycans from Ebola virus glycoproteins by matrix-assisted laser desorption/ionisation time-of-flight and negative ion electrospray tandem mass spectrometry.

The larger fragment of the transmembrane glycoprotein (GP1) and the soluble glycoprotein (sGP) of Ebola virus were expressed in human embryonic kidney cells and the secreted products were purified from the supernatant for carbohydrate analysis. The N-glycans were released with PNGase F from within sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS-PAGE) gels. Identification of the glycans was made with normal-phase high-performance liquid chromatography (HPLC), matrix-assisted laser desorption/ionisation mass spectrometry, negative ion electrospray ionisation fragmentation mass spectrometry and exoglycosidase digestion.

Identification of N-linked carbohydrates from severe acute respiratory syndrome (SARS) spike glycoprotein.

N-glycans were released from the SARS coronavirus (SARS-CoV) spike glycoprotein produced in Vero E6 cells and their structures were determined by a combination of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, negative ion electrospray collision-induced dissociation time-of-flight mass spectrometry and normal-phase high-performance liquid chromatography with exoglycosidase digestion. Major glycans were high-mannose (Man(5-9)GlcNAc(2)), hybrid and bi-, tri- and tetra-antennary complex with and without bisecting GlcNAc and core fucose. Complex glycans with fewer than the full complement of galactose residues were present and sialylation was negligible.

A pneumococcal MerR-like regulator and S-nitrosoglutathione reductase are required for systemic virulence.

A transcriptional regulator, NmlR(sp), has been identified in Streptococcus pneumoniae that is required for defense against nitric oxide (NO) stress. The nmlR(sp) gene is cotranscribed with adhC, which encodes an alcohol dehydrogenase that is able to reduce S-nitrosoglutathione (GSNO) with NADH as reductant. nmlR(sp) and adhC mutants exhibited a reduced level of NADH-GSNO oxidoreductase activity and were more susceptible to killing by NO than were wild-type cells.

The pneumococcal two-component signal transduction system RR/HK06 regulates CbpA and PspA by two distinct mechanisms.

We have previously shown that CbpA, a major pneumococcal virulence factor, is regulated by the two-component signal transduction system RR/HK06 (A. J. Standish, U.

Albomycin is an effective antibiotic, as exemplified with Yersinia enterocolitica and Streptococcus pneumoniae.

Albomycin belongs to the class of sideromycins, compounds composed of iron carriers linked to antibiotic moieties. Albomycin was found to be active against bacteria that have a functional ferric hydroxamate transport system meaning that bacteria will actively transport albomycin until they die. We examined the activity spectrum of albomycin for bacterial pathogens and found that Enterobacteriaceae except species of Proteus and Morganella were sensitive.

Contributions of pneumolysin, pneumococcal surface protein A (PspA), and PspC to pathogenicity of Streptococcus pneumoniae D39 in a mouse model.

Successful colonization of the upper respiratory tract by Streptococcus pneumoniae is an essential first step in the pathogenesis of pneumococcal disease. However, the bacterial and host factors that provoke the progression from asymptomatic colonization to invasive disease are yet to be fully defined. In this study, we investigated the effects of single and combined mutations in genes encoding pneumolysin (Ply), pneumococcal surface protein A (PspA), and pneumococcal surface protein C (PspC, also known as choline-binding protein A) on the pathogenicity of Streptococcus pneumoniae serotype 2 (D39) in mice.

The two-component signal transduction system RR06/HK06 regulates expression of cbpA in Streptococcus pneumoniae.

Streptococcus pneumoniae encounters a number of environmental niches in the body, including the nasopharynx, lungs, blood, middle ear, and brain. Recent studies have identified 13 putative two-component signal-transduction systems in S. pneumoniae, which are likely to be important for gene regulation in response to external stimuli.

Mass spectrometric characterization of proteins from the SARS virus: a preliminary report.

A new coronavirus has been implicated as the causative agent of severe acute respiratory syndrome (SARS). We have used convalescent sera from several SARS patients to detect proteins in the culture supernatants from cells exposed to lavage another SARS patient. The most prominent protein in the supernatant was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a approximately 46-kDa species.