bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased Biomass Production by Mesophilic Food-Associated Bacteria through Lowering the Growth Temperature from 30°C to 10°C
Authors: Seel Waldemar , Derichs Julia , Lipski André
Published: April 2016

Five isolates from chilled food and refrigerator inner surfaces and closely related reference strains of the species
Escherichia coli
,
Listeria monocytogenes
,
Staphylococcus xylosus
,
Bacillus cereus
,
Pedobacter nutrimenti
, and
Pedobacter panaciterrae
were tested for the effect of growth temperature (30°C and 10°C) on biomass formation. Growth was monitored via optical density, and biomass formation was measured at the early stationary phase based on the following parameters in complex and defined media: viable cell count, total cell count, cell dry weight, whole-cell protein content, and cell morphology. According to the lack of growth at 1°C, all strains were assigned to the thermal class of mesophiles. Glucose and ammonium consumption related to cell yield were analyzed in defined media. Except for the protein content, temperature had a significant (
t
test,
P
< 0.05) effect on all biomass formation parameters for each strain. The results show a significant difference between the isolates and the related reference strains. Isolates achieved an increase in biomass production between 20% and 110% at the 10°C temperature, which is 15 to 25°C lower than their maximum growth rate temperatures. In contrast, reference strains showed a maximum increase of only about 25%, and some reference strains showed no increase or a decrease of approximately 25%. As expected, growth rates for all strains were higher at 30°C than at 10°C, while biomass production for isolates was higher at 10°C than at 30°C. In contrast, the reference strains showed similar growth yields at the two temperatures. This also demonstrates for mesophilic bacterial strains more efficient nutrient assimilation during growth at low temperatures. Until now, this characteristic was attributed only to psychrophilic microorganisms.

IMPORTANCE
For several psychrophilic species, increased biomass formation was described at temperatures lower than optimum growth temperatures, which are defined by the highest growth rate. This work shows increased biomass formation at low growth temperatures for mesophilic isolates. A comparison with closely related reference strains from culture collections showed a significantly smaller increase or no increase in biomass formation. This indicates a loss of specific adaptive mechanisms (e.g., cold adaptation) for mesophiles during long-term cultivation. The increased biomass production for mesophiles under low-temperature conditions opens new avenues for a more efficient biotechnological transformation of nutrients to microbial biomass. These findings may also be important for risk assessment of cooled foods since risk potential is often correlated with the cell numbers present in food samples.
Use of Colistin and Other Critical Antimicrobials on Pig and Chicken Farms in Southern Vietnam and Its Association with Resistance in Commensal Escherichia coli Bacteria
Authors: Nguyen Nhung T. , Nguyen Hoa M. , Nguyen Cuong V. , Nguyen Trung V. , Nguyen Men T. , Thai Hieu Q. , Ho Mai H. , Thwaites Guy , Ngo Hoa T. , Baker Stephen , Carrique-Mas Juan
Published: April 2016

Antimicrobial resistance (AMR) is a global health problem, and emerging semi-intensive farming systems in Southeast Asia are major contributors to the AMR burden. We accessed 12 pig and chicken farms at key stages of production in Tien Giang Province, Vietnam, to measure antimicrobial usage and to investigate the prevalence of AMR to five critical antimicrobials (β-lactams, third-generation cephalosporins, quinolones, aminoglycosides, and polymyxins) and their corresponding molecular mechanisms among 180
Escherichia coli
isolates. Overall, 94.7 mg (interquartile range [IQR], 65.3 to 151.1) and 563.6 mg (IQR, 398.9 to 943.6) of antimicrobials was used to produce 1 kg (live weight) of chicken and pig, respectively. A median of 3 (out of 8) critical antimicrobials were used on pig farms.
E. coli
isolates exhibited a high prevalence of resistance to ampicillin (97.8% and 94.4% for chickens and pigs, respectively), ciprofloxacin (73.3% and 21.1%), gentamicin (42.2% and 35.6%), and colistin (22.2% and 24.4%). The prevalence of a recently discovered colistin resistance gene,
mcr-1
, was 19 to 22% and had strong agreement with phenotypic colistin resistance. We conducted plasmid conjugation experiments with 37
mcr-1
gene-positive
E. coli
isolates and successfully observed transfer of the gene in 54.0% of isolates through a plasmid of approximately 63 kb, consistent with one recently identified in China. We found no significant correlation between total use of antimicrobials at the farm level and AMR. These data provide additional insight into the role of
mcr-1
in colistin resistance on farms and outline the dynamics of phenotypic and genotypic AMR in semi-intensive farming systems in Vietnam.

IMPORTANCE
Our study provides accurate baseline information on levels of antimicrobial use, as well as on the dynamics of phenotypic and genotypic resistance for antimicrobials of critical importance among
E. coli
over the different stages of production in emerging pig and poultry production systems in Vietnam.
E. coli
isolates showed a high prevalence of resistance (>20%) to critically important antimicrobials, such as colistin, ciprofloxacin, and gentamicin. The underlying genetic mechanisms identified for colistin (the
mcr-1
gene) and quinolone (
gyrA
gene mutations) are likely to play a major role in AMR to those compounds. Conjugation experiments led to the identification of a 63-kb plasmid, similar to one recently identified in China, as the potential carrier of the
mcr-1
gene. These results should encourage greater restrictions of such antimicrobials in Southeast Asian farming systems.
Ultrastructural and Single-Cell-Level Characterization Reveals Metabolic Versatility in a Microbial Eukaryote Community from an Ice-Covered Antarctic Lake
Authors: Li Wei , Podar Mircea , Morgan-Kiss Rachael M.
Published: April 2016

The McMurdo Dry Valleys (MCM) of southern Victoria Land, Antarctica, harbor numerous ice-covered bodies of water that provide year-round liquid water oases for isolated food webs dominated by the microbial loop. Single-cell microbial eukaryotes (protists) occupy major trophic positions within this truncated food web, ranging from primary producers (e.g., chlorophytes, haptophytes, and cryptophytes) to tertiary predators (e.g., ciliates, dinoflagellates, and choanoflagellates). To advance the understanding of MCM protist ecology and the roles of MCM protists in nutrient and energy cycling, we investigated potential metabolic strategies and microbial interactions of key MCM protists isolated from a well-described lake (Lake Bonney). Fluorescence-activated cell sorting (FACS) of enrichment cultures, combined with single amplified genome/amplicon sequencing and fluorescence microscopy, revealed that MCM protists possess diverse potential metabolic capabilities and interactions. Two metabolically distinct bacterial clades (
Flavobacteria
and
Methylobacteriaceae
) were independently associated with two key MCM lake microalgae (
Isochrysis
and
Chlamydomonas
, respectively). We also report on the discovery of two heterotrophic nanoflagellates belonging to the Stramenopila supergroup, one of which lives as a parasite of
Chlamydomonas
, a dominate primary producer in the shallow, nutrient-poor layers of the lake.

IMPORTANCE
Single-cell eukaryotes called protists play critical roles in the cycling of organic matter in aquatic environments. In the ice-covered lakes of Antarctica, protists play key roles in the aquatic food web, providing the majority of organic carbon to the rest of the food web (photosynthetic protists) and acting as the major consumers at the top of the food web (predatory protists). In this study, we utilized a combination of techniques (microscopy, cell sorting, and genomic analysis) to describe the trophic abilities of Antarctic lake protists and their potential interactions with other microbes. Our work reveals that Antarctic lake protists rely on metabolic versatility for their energy and nutrient requirements in this unique and isolated environment.
Amino Sugars Enhance the Competitiveness of Beneficial Commensals with Streptococcus mutans through Multiple Mechanisms
Authors: Zeng Lin , Farivar Tanaz , Burne Robert A.
Published: April 2016

Biochemical and genetic aspects of the metabolism of the amino sugars
N
-acetylglucosamine (GlcNAc) and glucosamine (GlcN) by commensal oral streptococci and the effects of these sugars on interspecies competition with the dental caries pathogen
Streptococcus mutans
were explored. Multiple
S. mutans
wild-type isolates displayed long lag phases when transferred from glucose-containing medium to medium with GlcNAc as the primary carbohydrate source, but commensal streptococci did not. Competition in liquid coculture or dual-species biofilms between
S. mutans
and
Streptococcus gordonii
showed that
S. gordonii
was particularly dominant when the primary carbohydrate was GlcN or GlcNAc. Transcriptional and enzymatic assays showed that the catabolic pathway for GlcNAc was less highly induced in
S. mutans
than in
S. gordonii
. Exposure to H
2
O
2
, which is produced by
S. gordonii
and antagonizes the growth of
S. mutans
, led to reduced mRNA levels of
nagA
and
nagB
in
S. mutans
. When the gene for the transcriptional regulatory NagR was deleted in
S. gordonii
, the strain produced constitutively high levels of
nagA
(GlcNAc-6-P deacetylase),
nagB
(GlcN-6-P deaminase), and
glmS
(GlcN-6-P synthase) mRNA. Similar to NagR of
S. mutans
(NagR
Sm
), the
S. gordonii
NagR protein (NagR
Sg
) could bind to consensus binding sites (
dre
) in the
nagA
,
nagB
, and
glmS
promoter regions of
S. gordonii
. Notably, NagR
Sg
binding was inhibited by GlcN-6-P, but G-6-P had no effect, unlike for NagR
Sm
. This study expands the understanding of amino sugar metabolism and NagR-dependent gene regulation in streptococci and highlights the potential for therapeutic applications of amino sugars to prevent dental caries.

IMPORTANCE
Amino sugars are abundant in the biosphere, so the relative efficiency of particular bacteria in a given microbiota to metabolize these sources of carbon and nitrogen might have a profound impact on the ecology of the community. Our investigation reveals that several oral commensal bacteria have a much greater capacity to utilize amino sugars than the dental pathogen
Streptococcus mutans
and that the ability of the model commensal
Streptococcus gordonii
to compete against
S. mutans
is substantively enhanced by the presence of amino sugars commonly found in the oral cavity. The mechanisms underlying the greater capacity and competitive enhancements of the commensal are shown to depend on how the genes for the catabolic enzymes are regulated, the role of the allosteric modulators affecting such regulation, and the ability of amino sugars to enhance certain activities of the commensal that are antagonistic to
S. mutans
.
tRNA-Dependent Aminoacylation of an Amino Sugar Intermediate in the Biosynthesis of a Streptothricin-Related Antibiotic
Authors: Maruyama Chitose , Niikura Haruka , Izumikawa Miho , Hashimoto Junko , Shin-ya Kazuo , Komatsu Mamoru , Ikeda Haruo , Kuroda Makoto , Sekizuka Tsuyoshi , Ishikawa Jun , Hamano Yoshimitsu
Published: April 2016

The antibiotic streptothricin (ST) possesses an amino sugar bound to an
l
-β-lysine (β-Lys) residue via a peptide bond. The peptide bond formation has been shown to be catalyzed by a nonribosomal peptide synthetase (NRPS) during ST biosynthesis. The focus of this study is the closely related ST analogue BD-12, which carries a glycine-derived side chain rather than a β-Lys residue. Here, in
Streptomyces luteocolor
NBRC13826, we describe our biosynthetic studies of BD-12, which revealed that the peptide bond between the amino sugar and the glycine residue is catalyzed by a Fem-like enzyme (Orf11) in a tRNA-dependent manner rather than by an NRPS. Although there have been several reports of peptide bond-forming tRNA-dependent enzymes, to our knowledge, Orf11 is the first enzyme that can accept an amino sugar as a substrate. Our findings clearly demonstrate that the structural diversity of the side chains of ST-type compounds in nature is generated in an unusual manner via two distinct peptide bond-forming mechanisms. Moreover, the identification and functional analysis of Orf11 resulted in not only the production of new ST-related compounds, but also the provision of new insights into the structure-activity relationship of the ST-related antibiotics.

IMPORTANCE
The antibiotic streptothricin (ST) possesses an amino sugar bound to an
l
-β-lysine (β-Lys) side chain via a peptide bond formed by a nonribosomal peptide synthetase (NRPS). BD-12, an analogue of ST, carries a glycine-derived side chain rather than β-Lys, and here, we describe the BD-12-biosynthetic gene cluster from
Streptomyces
luteocolor
NBRC13826, which contains the
orf11
gene encoding a novel tRNA-dependent peptide bond-forming enzyme. The unique Fem-like enzyme (Orf11) accepts the amino sugar as a substrate and mediates the peptide formation between the amino sugar intermediate and glycine. Our studies demonstrate that the structural diversity of the side chains of ST-related compounds in nature is generated via two distinct peptide bond-forming mechanisms.
Photobacterium damselae subsp. damselae, an Emerging Fish Pathogen in the Black Sea: Evidence of a Multiclonal Origin
Authors: Terceti Mateus S. , Ogut Hamdi , Osorio Carlos R.
Published: April 2016

Photobacterium damselae
subsp.
damselae
is considered to be an emerging pathogen of marine fish of importance in aquaculture, with a notable increase in its geographical distribution during the last several years. In this study, we carried out for the first time to our knowledge a genetic and pathobiological characterization of 14 strains isolated from sea bass (
Dicentrarchus labrax
) reared in the Southeastern Black Sea, where high mortalities were observed at two aquaculture farms during the summer and autumn of 2011. Heterogeneity was evidenced among strains in phenotypical traits, such as sucrose fermentation, motility, and hemolysis. Although 11 of 14 isolates were hemolytic, we found that all of the isolates lacked the pPHDD1 virulence plasmid that encodes the phospholipase-D damselysin (Dly) and the pore-forming toxin PhlyP, two hemolysins previously reported to constitute major virulence factors for turbot. Subsequent PCR and sequencing analyses demonstrated that the 11 hemolytic isolates harbored a complete
hlyA
ch
gene, a chromosome I-borne gene that encodes HlyA
ch
hemolysin, whereas the three nonhemolytic isolates contained
hlyA
ch
pseudogenes caused by insertion sequence elements. Virulence challenges with two representative strains revealed that, albeit less virulent than the pPHDD1-harboring strain RM-71, the plasmidless
hlyA
ch
-positive and
hlyA
ch
-negative Black Sea isolates were pathogenic for sea bass. A phylogenetic analysis based on the
toxR
gene sequence uncovered a greater diversity in the isolates, indicating that the presence of this pathogen in the Black Sea was not caused by the introduction and spread of a single virulent clone but by the proliferation of different clones.

IMPORTANCE
The geographical distribution of marine bacterial pathogens is undergoing a worldwide increase. In particular, bacteria of the group vibrios are increasingly being isolated as the causative agents of disease in novel species of cultivated fish in areas where they had not been previously reported. Here we characterize for the first time to our knowledge a collection of isolates of the fish and human pathogen
Photobacterium damselae
subsp.
damselae
from diseased sea bass reared in the Black Sea. We uncovered great genetic diversity in the Black Sea isolates of this pathogen, suggesting a multiclonal origin. We also demonstrate for the first time that these isolates bear pathogenic potential for sea bass cultures by virulence challenges.
Application of AlkBGT and AlkL from Pseudomonas putida GPo1 for Selective Alkyl Ester ω-Oxyfunctionalization in Escherichia coli
Authors: van Nuland Youri M. , Eggink Gerrit , Weusthuis Ruud A.
Published: April 2016

The enzyme system AlkBGT from
Pseudomonas putida
GPo1 can efficiently ω-functionalize fatty acid methyl esters. Outer membrane protein AlkL boosts this ω-functionalization. In this report, it is shown that whole cells of
Escherichia coli
expressing the AlkBGT system can also ω-oxidize ethyl nonanoate (NAEE). Coexpression of AlkBGT and AlkL resulted in 1.7-fold-higher ω-oxidation activity on NAEE. With this strain, initial activity on NAEE was 70 U/g (dry weight) of cells (g
cdw
), 67% of the initial activity on methyl nonanoate. In time-lapse conversions with 5 mM NAEE the main product was 9-hydroxy NAEE (3.6 mM), but also 9-oxo NAEE (0.1 mM) and 9-carboxy NAEE (0.6 mM) were formed. AlkBGT also ω-oxidized ethyl, propyl, and butyl esters of fatty acids ranging from C
6
to C
10
. Increasing the length of the alkyl chain improved the ω-oxidation activity of AlkBGT on esters of C
6
and C
7
fatty acids. From these esters, application of butyl hexanoate resulted in the highest ω-oxidation activity, 82 U/g
cdw
. Coexpression of AlkL only had a positive effect on ω-functionalization of substrates with a total length of C
11
or longer. These findings indicate that AlkBGT(L) can be applied as a biocatalyst for ω-functionalization of ethyl, propyl, and butyl esters of medium-chain fatty acids.

IMPORTANCE
Fatty acid esters are promising renewable starting materials for the production of ω-hydroxy fatty acid esters (ω-HFAEs). ω-HFAEs can be used to produce sustainable polymers. Chemical conversion of the fatty acid esters to ω-HFAEs is challenging, as it generates by-products and needs harsh reaction conditions. Biocatalytic production is a promising alternative. In this study, biocatalytic conversion of fatty acid esters toward ω-HFAEs was investigated using whole cells. This was achieved with recombinant
Escherichia coli
cells that produce the AlkBGT enzymes. These enzymes can produce ω-HFAEs from a wide variety of fatty acid esters. Medium-chain-length acids (C
6
to C
10
) esterified with ethanol, propanol, or butanol were applied. This is a promising production platform for polymer building blocks that uses renewable substrates and mild reaction conditions.
Use of Redundant Exclusion PCR To Identify a Novel Bacillus thuringiensis Cry8 Toxin Gene from Pooled Genomic DNA
Authors: Zhang Fengjiao , Shu Changlong , Crickmore Neil , Li Yanqiu , Song Fuping , Liu Chunqin , Chen Zhibao , Zhang Jie
Published: April 2016

With the aim of optimizing the cloning of novel genes from a genomic pool containing many previously identified homologous genes, we designed a redundant exclusion PCR (RE-PCR) technique. In RE-PCR, a pair of generic amplification primers are combined with additional primers that are designed to specifically bind to redundant, unwanted genes that are a subset of those copied by the amplification primers. During RE-PCR, the specific primer blocks amplification of the full-length redundant gene. Using this method, we managed to clone a number of
cry8
or
cry9
toxin genes from a pool of
Bacillus thuringiensis
genomic DNA while excluding amplicons for
cry9Da
,
cry9Ea
, and
cry9Eb
. The method proved to be very efficient at increasing the number of rare genes in the resulting library. One such rare (and novel)
cry8
-like gene was expressed, and the encoded toxin was shown to be toxic to
Anomala corpulenta
.

IMPORTANCE
Protein toxins from the bacterium
Bacillus thuringiensis
are being increasingly used as biopesticides against a wide range of insect pests, yet the search for new or improved toxins is becoming more difficult, as traditional methods for gene discovery routinely isolate previously identified clones. This paper describes an approach that we have developed to increase the success rate for novel toxin gene identification through reducing or eliminating the cloning of previously characterized genes.
Motility of Electric Cable Bacteria
Authors: Bjerg Jesper Tataru , Damgaard Lars Riis , Holm Simon Agner , Schramm Andreas , Nielsen Lars Peter
Published: April 2016

Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces with a highly variable speed of 0.5 ± 0.3 μm s
−1
(mean ± standard deviation) and time between reversals of 155 ± 108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment.

IMPORTANCE
This study reports on the motility of cable bacteria, capable of transmitting electrons over centimeter distances. It gives us a new insight into their behavior in sediments and explains previously puzzling findings. Cable bacteria greatly influence their environment, and this article adds significantly to the body of knowledge about this organism.
The Acinetobacter baumannii Two-Component System AdeRS Regulates Genes Required for Multidrug Efflux, Biofilm Formation, and Virulence in a Strain-Specific Manner
Authors: Richmond Grace E. , Evans Laura P. , Anderson Michele J. , Wand Matthew E. , Bonney Laura C. , Ivens Alasdair , Chua Kim Lee , Webber Mark A. , Sutton J. Mark , Peterson Marnie L. , Piddock Laura J. V.
Published: April 2016

The opportunistic pathogen
Acinetobacter baumannii
is able to persist in the environment and is often multidrug resistant (MDR), causing difficulties in the treatment of infections. Here, we show that the two-component system AdeRS, which regulates the production of the AdeABC multidrug resistance efflux pump, is required for the formation of a protective biofilm in an
ex vivo
porcine mucosal model, which mimics a natural infection of the human epithelium. Interestingly, deletion of
adeB
impacted only on the ability of strain AYE to form a biofilm on plastic and only on the virulence of strain Singapore 1 for
Galleria mellonella
. RNA-Seq revealed that loss of AdeRS or AdeB significantly altered the transcriptional landscape, resulting in the changed expression of many genes, notably those associated with antimicrobial resistance and virulence interactions. For example,
A. baumannii
lacking AdeRS displayed decreased expression of
adeABC
,
pil
genes,
com
genes, and a
pgaC
-like gene, whereas loss of AdeB resulted in increased expression of
pil
and
com
genes and decreased expression of ferric acinetobactin transport system genes. These data define the scope of AdeRS-mediated regulation, show that changes in the production of AdeABC mediate important phenotypes controlled by AdeRS, and suggest that AdeABC is a viable target for antimicrobial drug and antibiofilm discovery.

IMPORTANCE
Acinetobacter baumannii
is a nosocomial pathogen and is an increasing problem in hospitals worldwide. This organism is often multidrug resistant, can persist in the environment, and forms a biofilm on environmental surfaces and wounds. Overproduction of efflux pumps can allow specific toxic compounds to be pumped out of the cell and can lead to multidrug resistance. This study demonstrates the role of the
A. baumannii
efflux pump AdeB, and its regulator AdeRS, in multidrug resistance, epithelial cell killing, and biofilm formation. Deletion of the genes encoding these systems led to increased susceptibility to antibiotics, decreased biofilm formation on biotic and abiotic surfaces, and decreased virulence. Our data suggest that inhibition of AdeB could prevent biofilm formation or colonization in patients by
A. baumannii
and provides a good target for drug discovery
.
The Eng1 β-Glucanase EnhancesHistoplasmaVirulence by Reducing β-Glucan Exposure
Authors: Garfoot Andrew L. , Shen Qian , Wüthrich Marcel , Klein Bruce S. , Rappleye Chad A.
Published: April 2016

The fungal pathogenHistoplasma capsulatumparasitizes host phagocytes. To avoid antimicrobial immune responses,Histoplasmayeasts must minimize their detection by host receptors while simultaneously interacting with the phagocyte. PathogenicHistoplasmayeast cells, but not avirulent mycelial cells, secrete the Eng1 protein, which is a member of the glycosylhydrolase 81 (GH81) family. We show thatHistoplasmaEng1 is a glucanase that hydrolyzes β-(1,3)-glycosyl linkages but is not required forHistoplasmagrowthin vitroor for cell separation. However,Histoplasmayeasts lacking Eng1 function have attenuated virulencein vivo, particularly during the cell-mediated immunity stage.Histoplasmayeasts deficient for Eng1 show increased exposure of cell wall β-glucans, which results in enhanced binding to the Dectin-1 β-glucan receptor. Consistent with this, Eng1-deficient yeasts trigger increased tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) cytokine production from macrophages and dendritic cells. While not responsible for large-scale cell wall structure and function, the secreted Eng1 reduces levels of exposed β-glucans at the yeast cell wall, thereby diminishing potential recognition by Dectin-1 and proinflammatory cytokine production by phagocytes. In α-glucan-producingHistoplasmastrains, Eng1 acts in concert with α-glucan to minimize β-glucan exposure: α-glucan provides a masking function by covering the β-glucan-rich cell wall, while Eng1 removes any remaining exposed β-glucans. Thus,HistoplasmaEng1 has evolved a specialized pathogenesis function to remove exposed β-glucans, thereby enhancing the ability of yeasts to escape detection by host phagocytes.

IMPORTANCEThe success ofHistoplasma capsulatumas an intracellular pathogen results, in part, from an ability to minimize its detection by receptors on phagocytic cells of the immune system. In this study, we showed thatHistoplasmapathogenic yeast cells, but not avirulent mycelia, secrete a β-glucanase, Eng1, which reduces recognition of fungal cell wall β-glucans. We demonstrated that the Eng1 β-glucanase promotesHistoplasmavirulence by reducing levels of surface-exposed β-glucans on yeast cells, thereby enablingHistoplasmayeasts to escape detection by the host β-glucan receptor, Dectin-1. As a consequence, phagocyte recognition ofHistoplasmayeasts is reduced, leading to less proinflammatory cytokine production by phagocytes and less control ofHistoplasmainfectionin vivo. Thus,Histoplasmayeasts express two mechanisms to avoid phagocyte detection: masking of cell wall β-glucans by α-glucan and enzymatic removal of exposed β-glucans by the Eng1 β-glucanase.
Electroacupuncture and Cognitive Behavioural Therapy for Sub-Syndromal Depression among Undergraduates: A Controlled Clinical Trial
Authors: Guo Tianwei , Guo Zhuo , Zhang Wenyue , Ma Wenhao , Yang Xinjing , Yang Xueqin , Hwang Jiwon , He Xiaotian , Chen Xinyi , Ya Tu
Published: April 2016

Background

Individuals with sub-syndromal depression (SSD) are at increased risk of incident depressive disorders; however, the ideal therapeutic approach to SSD remains unknown.

Objective

To evaluate the effects of electroacupuncture (EA) and cognitive behavioural therapy (CBT), alone or in combination, on depressive symptoms.

Methods

Undergraduate students with SSD were recruited and allocated to one of four groups based on their preferences: EA (n=6), CBT (n=10), EA+CBT (n=6), and untreated control (n=11) groups. Six weeks of treatment were provided in the first three groups. Clinical outcomes were measured using the 17-item Hamilton Depression (HAMD-17) rating scale, Center for Epidemiologic Depression (CES-D) scale, WHO Quality of Life-Brief version (WHOQOL-BREF) questionnaire, and clinical remission rate.

Results

All 33 subjects were included in an intent-to-treat analysis. Statistically significant improvements in HAMD-17, CES-D, and WHOQOL-BREF scores and a higher remission rate were found in the EA, CBT, and EA+CBT intervention groups compared with the control group (all p<0.05). No significant differences were found between the three intervention groups. HAMD-17 factor score analysis revealed that EA reduced sleep disturbance scores more than CBT or EA+CBT (p<0.05), and CBT reduced retardation scores more than EA (p<0.01). EA+CBT reduced anxiety/somatisation scores more than EA or CBT (p<0.05) and retardation scores more than EA (p<0.05).

Conclusions

Early intervention may alleviate depressive symptoms in SSD. EA and CBT may have differential effects on certain symptoms. Combination therapy targeting both physical and psychological symptoms may represent an ideal strategy for SSD intervention. However, randomised trials with larger sample sizes are needed.

Trial Registration Number

ChiCTR-TRC-10000889; Results.
Colchicine for children with pericarditis: systematic review of clinical studies
Authors: Alabed Samer , Pérez-Gaxiola Giordano , Burls Amanda
Published: April 2016

Objective

To review the evidence for the efficacy and safety of colchicine in children with pericarditis.

Design

Systematic review.

Search strategy

The following databases were searched for studies about colchicine in children with pericarditis (June 2015): Cochrane Central, Medline, EMBASE and LILACS.

Eligibility criteria

All observational and experimental studies on humans with any length of follow-up and no limitations on language or publication status were included. The outcomes studied were recurrences of pericarditis and adverse events.

Data extraction

Two authors extracted data and assessed quality of included studies using the Cochrane risk of bias tool for non-randomised trials.

Results

Two case series and nine case reports reported the use of colchicine in a total of 86 children with pericarditis. Five articles including 74 paediatric patients were in favour of colchicine in preventing further pericarditis recurrences. Six studies including 12 patients showed that colchicine did not prevent recurrences of pericarditis.

Limitations

No randomised controlled trials (RCTs) were found.

Conclusions

Although colchicine is an established treatment for pericarditis in adults, it is not routinely used in children. There is not enough evidence to support or discourage the use of colchicine in children with pericarditis. Further research in the form of large double-blind RCTs is needed to establish the efficacy of colchicine in children with pericarditis.
Determinants for tuberculosis in HIV-infected adults in Northwest Ethiopia: a multicentre case–control study
Authors: Alemu Yihun Mulugeta , Awoke Worku , Wilder-Smith Annalies
Published: April 2016

Objective

The objective of this study was to identify determinants for tuberculosis (TB) among HIV-infected adults in Northwest Ethiopia.

Design

Case–control study.

Setting

Three hospitals and 10 health centres in Northwest Ethiopia.

Participants

A total of 446 individuals consented to participate in the study (150 cases and 296 controls). Cases were HIV-infected adults diagnosed with active TB, and controls were HIV-infected adults without active TB.

Main outcome measure

The link between TB and determinants was assessed using logistic regression. Determinants were categorised as sociodemographic, host-related, clinical and environmental.

Results

Smoking (adjusted OR (AOR) 5.47; 95% CI 2.26 to 13.22), presence of a TB patient in the family (AOR 2.66; 95% CI 1.25 to 5.66), alcohol consumption (AOR 2.49; 95% CI 1.29 to 4.80) and chewing khat (AOR 2.22; 95% CI 1.11 to 4.41) were independent determinants for increased occurrence of TB. Highly active antiretroviral therapy (HAART) (AOR 0.25; 95% CI 0.13 to 0.51), isoniazid preventive therapy (IPT) (AOR 0.22; 95% CI 0.11 to 0.41) and cotrimoxazole preventive therapy (AOR 0.32; 95% CI 0.19 to 0.55) had a protective effect against TB.

Conclusions

HIV-infected adults with substance abuse (tobacco smoking, khat chewing and alcohol) should be prioritised for TB screening. This study reaffirmed that HAART and IPT are some of the best strategies for reducing TB occurrence in HIV-infected adults. These findings provide impetus to intensify tracing of TB household contacts.
Sex differences in aneurysm morphologies and clinical outcomes in ruptured anterior communicating artery aneurysms: a retrospective study
Authors: Lin Boli , Chen Weijian , Ruan Lei , Chen Yongchun , Zhong Ming , Zhuge Qichuan , Fan Liang Hao , Zhao Bing , Yang Yunjun
Published: April 2016

Objectives

Ruptured anterior communicating artery (ACoA) aneurysms occur more frequently in men. The purpose of the study was to investigate sex difference in aneurysm morphologies and clinical outcomes in patients with ruptured ACoA aneurysms.

Setting

A tertiary referral hospital.

Participants

A total of 574 consecutive patients with ACoA aneurysms were admitted to our hospital from December 2007 to February 2015. In all, 474 patients (257 men and 217 women) with ruptured ACoA aneurysms were included in the study.

Main outcome measures

Aneurysm morphologies were measured using computed tomographic angiography and clinical outcomes were measured with Glasgow coma score at discharge.

Results

The aneurysm sizes (p=0.001), aneurysm heights (p=0.011), size ratios (p<0.001), flow angles (p=0.047) and vessel angles (p=0.046) were larger in the male patients than in the females. The female patients more often had larger vessel sizes (p=0.002). Multivariate logistic analysis revealed that significant differences in aneurysm morphologies between men and women were aneurysm size (OR 1.1, 95% CI 1.0 to 1.3; p=0.036), aneurysm height (OR 0.8, 95% CI 0. to 0.9; p=0.006) and size ratio (OR 1.4, 95% CI 0.5 to 1.7; p=0.001). There were no statistically significant differences in the outcomes between men and women (OR 1.0, 95% CI 0.6 to 1.7, p=0.857).

Conclusions

The men were independently associated with larger aneurysm sizes, greater aneurysm heights and larger size ratios. Sex was not a risk factor for poor outcome in patients with ruptured ACoA aneurysms.
Determining the frequency of pathogenic germline variants from exome sequencing in patients with castrate-resistant prostate cancer
Authors: Hart Steven N , Ellingson Marissa S , Schahl Kim , Vedell Peter T , Carlson Rachel E , Sinnwell Jason P , Barman Poulami , Sicotte Hugues , Eckel-Passow Jeanette E , Wang Liguo , Kalari Krishna R , Qin Rui , Kruisselbrink Teresa M , Jimenez Rafael E , Bryce Alan H , Tan Winston , Weinshilboum Richard , Wang Liewei , Kohli Manish
Published: April 2016

Objectives

To determine the frequency of pathogenic inherited mutations in 157 select genes from patients with metastatic castrate-resistant prostate cancer (mCRPC).

Design

Observational.

Setting

Multisite US-based cohort.

Participants

Seventy-one adult male patients with histological confirmation of prostate cancer, and had progressive disease while on androgen deprivation therapy.

Results

Twelve patients (17.4%) showed evidence of carrying pathogenic or likely pathogenic germline variants in theATM,ATR,BRCA2,FANCL,MSR1,MUTYH,RB1,TSHRandWRNgenes. All but one patient opted in to receive clinically actionable results at the time of study initiation. We also found that pathogenic germlineBRCA2variants appear to be enriched in mCRPC compared to familial prostate cancers.

Conclusions

Pathogenic variants in cancer-susceptibility genes are frequently observed in patients with mCRPC. A substantial proportion of patients with mCRPC or their family members would derive clinical utility from mutation screening.

Trial registration number

NCT01953640; Results.
National programmes for validating physician competence and fitness for practice: a scoping review
Authors: Horsley Tanya , Lockyer Jocelyn , Cogo Elise , Zeiter Jeanie , Bursey Ford , Campbell Craig
Published: April 2016

Objective

To explore and categorise the state of existing literature for national programmes designed to affirm or establish the continuing competence of physicians.

Design

Scoping review.

Data sources

MEDLINE, ERIC, Sociological Abstracts, web/grey literature (2000–2014).

Selection

Included when a record described a (1) national-level physician validation system, (2) recognised as a system for affirming competence and (3) reported relevant data.

Data extraction

Using bibliographic software, title and abstracts were reviewed using an assessment matrix to ensure duplicate, paired screening. Dyads included both a methodologist and content expert on each assessment, reflective of evidence-informed best practices to decrease errors.

Results

45 reports were included. Publication dates ranged from 2002 to 2014 with the majority of publications occurring in the previous six years (n=35). Country of origin—defined as that of the primary author—included the USA (N=32), the UK (N=8), Canada (N=3), Kuwait (N=1) and Australia (N=1). Three broad themes emerged from this heterogeneous data set: contemporary national programmes, contextual factors and terminological consistency. Four national physician validation systems emerged from the data: the American Board of Medical Specialties Maintenance of Certification Program, the Federation of State Medical Boards Maintenance of Licensure Program, the Canadian Revalidation Program and the UK Revalidation Program. Three contextual factors emerged as stimuli for the implementation of national validation systems: medical regulation, quality of care and professional competence. Finally, great variation among the definitions of key terms was identified.

Conclusions

There is an emerging literature focusing on national physician validation systems. Four major systems have been implemented in recent years and it is anticipated that more will follow. Much of this work is descriptive, and gaps exist for the extent to which systems build on current evidence or theory. Terminology is highly variable across programmes for validating physician competence and fitness for practice.
Epidemiology of road traffic injuries in Nepal, 2001–2013: systematic review and secondary data analysis
Authors: Karkee Rajendra , Lee Andy H
Published: April 2016

Objective

To investigate the epidemiology of road traffic injury (RTI) in Nepal for the period 2001–2013.

Methods

2 approaches, secondary data analysis and systematic literature review, were adopted. RTI data were retrieved from traffic police records and analysed for the incidence of RTI. Electronic databases were searched for published articles that described the epidemiology of RTI in Nepal.

Results

A total of 95 902 crashes, 100 499 injuries and 14 512 deaths were recorded by the traffic police over the 12-year period, 2001–2013. The mortality rate increased from 4/100 000 population in 2001–2002 to 7/100 000 population in 2011–2012. There were relatively more reported crashes yet fewer deaths in Kathmandu valley than the rest of the country. Of the 20 articles related to RTI, only 11 articles met the eligibility criteria, but these were mainly descriptive case series or cross-sectional hospital-based studies. The majority of RTI were reported to occur among motorcyclists and pedestrians, in males, and in the age group 20–40 years. The common sites of injury were lower and upper extremities. Only 3 articles mentioned possible causes of accidents that include pedestrian road behaviour, alcohol consumption and improper bus driving.

Conclusions

Nepal suffers a heavy burden of RTI, with higher fatalities on highways out of Kathmandu valley caused by bus crashes in hilly districts. The majority of published studies on RTI are descriptive and hospital based, indicating the need for more thorough investigation of causes of RTI and systematic recording of crashes for the development of effective interventions.
What are parents' perspectives on psychological empowerment in the MMR vaccination decision? A focus group study
Authors: Fadda Marta , Galimberti Elisa , Carraro Valter , Schulz Peter J
Published: April 2016

Objectives

Most developed countries do not have compulsory immunisation requirements, but instead issue recommendations. Although parents are expected to make an informed, autonomous (ie, empowered) decision regarding their children's vaccinations, there is no evidence about how parents' interpret this demand nor on the latitude of their decision-making. The goal of this study is to gain insights from parents residing in a low measles-mumps-rubella (MMR) uptake area on what constitutes feelings of empowerment in the decision they have to make on their child's MMR vaccination.

Design

A qualitative study employing focus group interviews.

Setting

11 vaccination centres and hospitals in the Province of Trento, Italy.

Participants

24 mothers and 4 fathers of children for whom the MMR vaccination decision was still pending participated in 6 focus groups.

Results

Autonomy and competence were salient themes in relation to empowerment, and were further connected with beliefs regarding legal responsibility and ethics of freedom concerning the decision, parents' relationship with the paediatrician (trust), feelings of relevance of the decision and related stress, and seeking, avoidance, or fear of vaccination-related information. Competence was interpreted as medical knowledge and information-seeking skills, but it was also related to the extent parents perceived the paediatrician to be competent.

Conclusions

Since parents' interpretation of empowerment goes beyond mere perceptions of being informed and autonomous and differs across individuals, it is important that this construct be correctly interpreted and implemented by best practice, for instance by explicitly adopting a relational conception of autonomy. Knowing whether parents want to make an empowered decision and what their information and autonomy needs are might help health professionals adapt their communication about immunisation, and promote parental perception of making an informed, autonomous decision.
Weekly miscarriage rates in a community-based prospective cohort study in rural western Kenya
Authors: Dellicour Stephanie , Aol George , Ouma Peter , Yan Nicole , Bigogo Godfrey , Hamel Mary J , Burton Deron C , Oneko Martina , Breiman Robert F , Slutsker Laurence , Feikin Daniel , Kariuki Simon , Odhiambo Frank , Calip Gregory , Stergachis Andreas , Laserson Kayla F , ter Kuile Feiko O , Desai Meghna
Published: April 2016

Objective

Information on adverse pregnancy outcomes is important to monitor the impact of public health interventions. Miscarriage is a challenging end point to ascertain and there is scarce information on its rate in low-income countries. The objective was to estimate the background rate and cumulative probability of miscarriage in rural western Kenya.

Design

This was a population-based prospective cohort.

Participants and setting

Women of childbearing age were followed prospectively to identify pregnancies and ascertain their outcomes in Siaya County, western Kenya. The cohort study was carried out in 33 adjacent villages under health and demographic surveillance.

Outcome measure

Miscarriage.

Results

Between 2011 and 2013, among 5536 women of childbearing age, 1453 pregnancies were detected and 1134 were included in the analysis. The cumulative probability was 18.9%. The weekly miscarriage rate declined steadily with increasing gestation until approximately 20 weeks. Known risk factors for miscarriage such as maternal age, gravidity, occupation, household wealth and HIV infection were confirmed.

Conclusions

This is the first report of weekly miscarriage rates in a rural African setting in the context of high HIV and malaria prevalence. Future studies should consider the involvement of community health workers to identify the pregnancy cohort of early gestation for better data on the actual number of pregnancies and the assessment of miscarriage.
Follow-up study of the regional quota system of Japanese medical schools and prefecture scholarship programmes: a study protocol
Authors: Matsumoto Masatoshi , Takeuchi Keisuke , Tanaka Junko , Tazuma Susumu , Inoue Kazuo , Owaki Tetsuhiro , Iguchi Seitaro , Maeda Takahiro
Published: April 2016

Introduction

Given the shortage of physicians, particularly in rural areas, the Japanese government has rapidly expanded the number of medical school students by addingchiikiwaku(regional quotas) since 2008. Quota entrants now account for 17% of all medical school entrants. Quota entrants are usually local high school graduates who receive a scholarship from the prefecture government. In exchange, they temporarily practise in that prefecture, including its rural areas, after graduation. Many prefectures also have scholarship programmes for non-quota students in exchange for postgraduate in-prefecture practice. The objective of this cohort study, conducted by the Japanese Council for Community-based Medical Education, is to evaluate the outcomes of the quota admission system and prefecture scholarship programmes nationwide.

Methods and analysis

There are 3 groups of study participants: quota without scholarship, quota with scholarship and non-quota with scholarship. Under the support of government ministries and the Association of Japan Medical Colleges, and participation of all prefectures and medical schools, passing rate of the National Physician License Examination, scholarship buy-out rate, geographic distribution and specialties distribution of each group are analysed. Participants who voluntarily participated are followed by linking their baseline information to data in the government's biennial Physician Census. Results to date have shown that, despite medical schools' concerns about academic quality, the passing rate of the National Physician License Examination in each group was higher than that of all medical school graduates.

Ethics and dissemination

The Ethics Committee for Epidemiological Research of Hiroshima University and the Research Ethics Committee of Nagasaki University Graduate School of Biomedical Sciences permitted this study. No individually identifiable results will be presented in conferences or published in journals. The aggregated results will be reported to concerned government ministries, associations, prefectures and medical schools as data for future policy planning.
Exercise and BMI z-score in overweight and obese children and adolescents: protocol for a systematic review and network meta-analysis of randomised trials
Authors: Kelley George A , Kelley Kristi S
Published: April 2016

Introduction

While overweight and obesity in children and adolescents is a major global health problem, the effects of exercise on overweight and obesity in children and adolescents are not well established despite numerous studies on this topic. The purpose of this study is to use the network meta-analytic approach to determine the effects of exercise (aerobic, strength training or both) on body mass index (BMI) z-score in overweight and obese children and adolescents.

Methods and analysis

Randomised exercise intervention trials>4 weeks, published in any language between 1 January 1990 and 31 September 2015, and which include direct and/or indirect evidence, will be included. Studies will be retrieved by searching 6 electronic databases, cross-referencing and expert review. Dual abstraction of data will occur. The primary outcome will be changes in BMI z-score while the secondary outcome will be changes in body weight in kilograms (kg). Risk of bias will be assessed using the Cochrane risk of bias assessment instrument while confidence in the cumulative evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) instrument for network meta-analysis. Network meta-analysis will be performed using multivariate random-effects meta-regression models. The surface under the cumulative ranking curve will be used to provide a hierarchy of exercise treatments (aerobic, strength training or both).

Dissemination

The results of this study will be presented at a professional conference and published in a peer-reviewed journal.

Trial registration number

CRD42015026377.