bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenomenological investigation of organic modified cements as biocompatible substrates interfacing model marine organisms
Authors: Zhao Jinglun , Yuan Tao , Huang Hui , Lu Xiaolin
Published: September 2024

Organic modification can generally endow inorganic materials with novel and promotional characteristics to fit into new functionalities. In this paper, new cement-based composite materials, with Portland cement as the substrate and polyacrylamide (PAM, alone) and PAM/chitosan as the functional components mixed with cement (bulk modified) or served as the surface coating (surface modified), were prepared and engineered as sampling substrates for biofilm and coral co-culture. In comparison to the bulk modified substrate and pure cement material, the surface modified substrate showed a balanced mechanical property, considering both bending and compressive strengths and distinctive surface features toward facilitating biofilm and coral growth, as characterized by spectroscopic, morphological, mechanical, and biofilm and coral co-culture experiments. We, thus, believe that the as-prepared surface modified substrate has the very potential to be applied as a substitute/alternative for the conventional cement material in the construction and engineering of artificial facilities with ecological protection functions.
Glycosylation of 6-gingerol and unusual spontaneous deglucosylation of two novel intermediates to form 6-shogaol-4′-
O-β
-glucoside by bacterial glycosyltransferase
Authors: Chang Te-Sheng , Ding Hsiou-Yu , Wu Jiumn-Yih , Lin Han-Ying , Wang Tzi-Yuan
Published: September 2024

6-Gingerol is a major phenolic compound within ginger (
Zingiber officinale
), often used in healthcare; however, its lower bioavailability is partly due to its poor solubility. Four bacterial glycosyltransferases (GTs) were tested to glycosylate 6-gingerol into soluble gingerol glucosides.
Bs
UGT489 was a suitable GT to biotransform 6-gingerol into five significant products, which could be identified via nucleic magnetic resonance and mass spectrometry as 6-gingerol-4′,5-
O
-
β
-diglucoside (
1
), 6-gingerol-4′-
O
-
β
-glucoside (
2
), 6-gingerol-5-
O
-
β
-glucoside (
3
), 6-shogaol-4′-
O
-
β
-glucoside (
4
), and 6-shogaol (
5
). The enzyme kinetics of
Bs
UGT489 showed substrate inhibition toward 6-gingerol for producing two glucosides. The kinetic parameters were determined as
K
M
(110 µM),
k
cat
(862 min
−1
), and
K
I
(571 µM) for the production of 6-gingerol-4′-
O-β
-glucoside (
2
) and
K
M
(104 µM),
k
cat
(889 min
−1
), and
K
I
(545 µM) for the production of 6-gingerol-5-
O-β
-glucoside (
3
). The aqueous solubility of the three 6-gingerol glucosides, compound (
1
) to (
3
), was greatly improved. However, 6-shogaol-4′-
O
-
β
-glucoside (
4
) was found to be a product biotransformed from 6-shogaol (
5
). This study first confirmed that the glucose moiety at the C-5 position of both 6-gingerol-4′,5-
O
-
β
-diglucoside (
1
) and 6-gingerol-5-
O
-
β
-glucoside (
3
) caused spontaneous deglucosylation through
β
-elimination to form 6-shogaol-4′-
O
-
β
-glucoside (
4
) and 6-shogaol (
5
), respectively. Moreover, the GTs could glycosylate 6-shogaol to form 6-shogaol-4′-
O
-
β
-glucoside (
4
). The assays showed 6-shogaol-4′-
O
-
β
-glucoside (
4
) had higher anti-inflammatory activity (IC
50
value of 10.3 ± 0.2 µM) than 6-gingerol. The 6-gingerol-5-
O
-
β
-glucoside (
3
) possessed 346-fold higher solubility than 6-shogaol, in which the highly soluble glucoside is a potential prodrug of 6-shogaol via spontaneous deglucosylation. This unusual deglucosylation plays a vital role in influencing the anti-inflammatory activity.

IMPORTANCE

Both 6-gingerols and 6-shogaol possess multiple bioactivities. However, their poor solubility limits their application. The present study used bacterial GTs to catalyze the glycosylation of 6-gingerol, and the resulting gingerol glycosides were found to be new compounds with improved solubility and anti-inflammatory activity. In addition, two of the 6-gingerol glucosides were found to undergo spontaneous deglucosylation to form 6-shogaol or 6-shogaol glucosides. The unique spontaneous deglucosylation property of the new 6-gingerol glucosides makes them a good candidate for the prodrug of 6-shogaol.
Molecular dissection of the chromosome partitioning protein RocS and regulation by phosphorylation
Authors: Demuysere Margaux , Ducret Adrien , Grangeasse Christophe
Published: September 2024

Chromosome segregation in bacteria is a critical process ensuring that each daughter cell receives an accurate copy of the genetic material during cell division. Active segregation factors, such as the ParABS system or SMC complexes, are usually essential for this process, but they are surprisingly dispensable in
Streptococcus pneumoniae
. Rather, chromosome segregation in
S. pneumoniae
relies on the protein Regulator of Chromosome Segregation (RocS), although the molecular mechanisms involved remain elusive. By combining genetics,
in vivo
imaging, and biochemical approaches, we dissected the molecular features of RocS involved in chromosome segregation. We investigated the respective functions of the three RocS domains, specifically the C-terminal amphipathic helix (AH), the N-terminal DNA-binding domain (DBD), and the coiled-coil domain (CCD) separating the AH and the DBD. Notably, we found that a single AH is not sufficient for membrane binding and that RocS requires prior oligomerization to interact with the membrane. We further demonstrated that this self-interaction was driven by the N-terminal part of the CCD. On the other hand, we revealed that the C-terminal part of the CCD corresponds to a domain of unknown function (DUF 536) and is defined by three conserved glutamines, which play a crucial role in RocS-mediated chromosome segregation. Finally, we showed that the DBD is phosphorylated by the unique serine-threonine kinase of
S. pneumoniae
StkP and that mimicking this phosphorylation abrogated RocS binding to DNA. Overall, this study offers new insights into chromosome segregation in Streptococci and paves the way for a deeper understanding of RocS-like proteins in other bacteria.

IMPORTANCE

Bacteria have evolved a variety of mechanisms to properly segregate their genetic material during cell division. In this study, we performed a molecular dissection of the chromosome partitioning protein Regulator of Chromosome Segregation (RocS), a pillar element of chromosome segregation in
S. pneumoniae
that is also generally conserved in the
Streptococcaceae
family. Our systematic investigation sheds light on the molecular features required for successful pneumococcal chromosome segregation and the regulation of RocS by phosphorylation. In addition, our study also revealed that RocS shares functional domains with the Par protein, involved in an atypical plasmid segregation system. Therefore, we expect that our findings may serve to extend our understanding of RocS and RocS-like proteins while broadening the repertoire of partitioning systems used in bacteria.
High-throughput sequencing-based neutralization assay reveals how repeated vaccinations impact titers to recent human H1N1 influenza strains
Authors: Loes Andrea N. , Tarabi Rosario Araceli L. , Huddleston John , Touyon Lisa , Wong Sook San , Cheng Samuel M. S. , Leung Nancy H. L. , Hannon William W. , Bedford Trevor , Cobey Sarah , Cowling Benjamin J. , Bloom Jesse D.
Published: September 2024

The high genetic diversity of influenza viruses means that traditional serological assays have too low throughput to measure serum antibody neutralization titers against all relevant strains. To overcome this challenge, we developed a sequencing-based neutralization assay that simultaneously measures titers against many viral strains using small serum volumes using a workflow similar to traditional neutralization assays. The key innovation is to incorporate unique nucleotide barcodes into the hemagglutinin (HA) genomic segment, and then pool viruses with numerous different barcoded HA variants and quantify the infectivity of all of them simultaneously using next-generation sequencing. With this approach, a single researcher performed the equivalent of 2,880 traditional neutralization assays (80 serum samples against 36 viral strains) in approximately 1 month. We applied the sequencing-based assay to quantify the impact of influenza vaccination on neutralization titers against recent human H1N1 strains for individuals who had or had not also received a vaccine in the previous year. We found that the viral strain specificities of the neutralizing antibodies elicited by vaccination vary among individuals and that vaccination induced a smaller increase in titers for individuals who had also received a vaccine the previous year—although the titers 6 months after vaccination were similar in individuals with and without the previous-year vaccination. We also identified a subset of individuals with low titers to a subclade of recent H1N1 even after vaccination. We provide an experimental protocol (
dx.doi.org/10.17504/protocols.io.kqdg3xdmpg25/v1
) and computational pipeline (
https://github.com/jbloomlab/seqneut-pipeline
) for the sequencing-based neutralization assays to facilitate the use of this method by others.

IMPORTANCE

We describe a new approach that can rapidly measure how the antibodies in human serum inhibit infection by many different influenza strains. This new approach is useful for understanding how viral evolution affects antibody immunity. We apply the approach to study the effect of repeated influenza vaccination.
Herpes simplex virus 1 inhibits phosphorylation of RNA polymerase II CTD serine-7
Authors: Whisnant Adam W. , Dyck Dionisi Oliver , Salazar Sanchez Valeria , Rappold Julia M. , Djakovic Lara , Grothey Arnhild , Marante Ana Luiza , Fischer Patrick , Peng Shitao , Wolf Katharina , Hennig Thomas , Dölken Lars
Published: September 2024

Transcriptional activity of RNA polymerase II (Pol II) is influenced by post-translational modifications of the C-terminal domain (CTD) of the largest Pol II subunit, RPB1. Herpes simplex virus type 1 (HSV-1) usurps the cellular transcriptional machinery during lytic infection to efficiently express viral mRNA and shut down host gene expression. The viral immediate-early protein ICP22 interferes with serine 2 phosphorylation (pS2) by targeting CDK9 and other CDKs, but the full functional implications of this are not well understood. Using Western blotting, we report that HSV-1 also induces a loss of serine 7 phosphorylation (pS7) of the CTD during lytic infection, requiring expression of the two immediate-early proteins ICP22 and ICP27. ICP27 has also been proposed to target RPB1 for degradation, but we show that pS2/S7 loss precedes the drop in total protein levels. Cells with the RPB1 polyubiquitination site mutation K1268R, preventing proteasomal degradation during transcription-coupled DNA repair, displayed loss of pS2/S7 but retained higher overall RPB1 protein levels later in infection, indicating this pathway is not involved in early CTD dysregulation but may mediate bulk protein loss later. Using α-amanitin-resistant CTD mutants, we observed differential requirements for Ser2 and Ser7 for the production of viral proteins, with Ser2 facilitating viral immediate-early genes and Ser7 appearing dispensable. Despite dysregulation of CTD phosphorylation and different requirements for Ser2/7, all CTD modifications tested could be visualized in viral replication compartments with immunofluorescence. These data expand the known means that HSV employs to create pro-viral transcriptional environments at the expense of host responses.

IMPORTANCE

Cells rapidly induce changes in the transcription of RNA in response to stress and pathogens. Herpes simplex virus (HSV) disrupts many processes of host mRNA transcription, and it is necessary to separate the actions of viral proteins from cellular responses. Here, we demonstrate that viral proteins inhibit two key phosphorylation patterns on the C-terminal domain (CTD) of cellular RNA polymerase II and that this is separate from the degradation of polymerases later in infection. Furthermore, we show that viral genes do not require the full “CTD code.” Together, these data distinguish multiple steps in the remodeling of RNA polymerase during infection and suggest that shared transcriptional phenotypes during stress responses do not revolve around a core disruption of CTD modifications.
Growth defect of domain III glycoprotein B mutants of human cytomegalovirus reverted by compensatory mutations co-localizing in post-fusion conformation
Authors: Mollik Madlen , Rohorzka Andreas , Chen Xiaohan , Kropff Barbara , Eisler Lukas , Külekci Büsra , Puchhammer-Stöckl Elisabeth , Thomas Marco , Görzer Irene
Published: September 2024

Cell entry is a crucial step for a virus to infect a host cell. Human cytomegalovirus utilizes glycoprotein B (gB) to fuse the viral and host cell membranes upon receptor binding of gH/gL-containing complexes. Fusion is mediated by major conformational changes of gB from a metastable pre-fusion to a stable post-fusion state whereby the central trimeric coiled-coils, formed by domain (Dom)III α helices, remain structurally nearly unchanged. To better understand the role of the stable core, we individually introduced three potentially helix-breaking or one disulfide bond-breaking mutation in the DIII α3 to study different aspects of the viral behavior upon long-term culturing. Two of the three helix-breaking mutations, gB_Y494P and gB_I495P, were lethal for the virus in either fibroblasts or epithelial cells. The third substitution, gB_G493P, on the other hand, displayed a delayed replication and spread, which was more pronounced in epithelial cells, hinting at an impaired fusion. Interestingly, the disulfide bond-breaker mutation, gB_C507S, performed strikingly differently in the two cell types - lethal in epithelial cells and an atypical phenotype in fibroblasts, respectively. Replication curve analyses paired with the infection efficiency, the spread morphology, and the cell–cell fusogenicity suggest a dysregulated fusion process, which could be reverted by second-site mutations mapping predominantly to gB DomV. Our findings underline the functional importance of a stable DomIII core for a well-regulated DomV rearrangement during fusion.

IMPORTANCE

Human cytomegalovirus (HCMV) can establish a lifelong infection. In most people, the infection follows an asymptomatic course; however, it is a major cause of morbidity and mortality in immunocompromised patients or neonates. HCMV has a very broad cell tropism, ranging from fibroblasts to epi- and endothelial cells. The virus uses different entry pathways utilizing the core fusion machinery consisting of glycoprotein complexes gH/gL and glycoprotein B (gB). The fusion protein gB undergoes fundamental rearrangements from a metastable pre-fusion to a stable post-fusion conformation. Here, we characterized the viral behavior after the introduction of four single-point mutations in the gB central core. These led to various cell type-specific atypical phenotypes and the emergence of compensatory mutations, demonstrating an important interaction between domains III and V. We provide a new basis for the development of a structurally and functionally altered gB, which can further serve as a tool for drug and vaccine development.
Investigation of Zur-regulated metal transport systems reveals an unexpected role of pyochelin in zinc homeostasis
Authors: Secli Valerio , Michetti Emma , Pacello Francesca , Iacovelli Federico , Falconi Mattia , Astolfi Maria Luisa , Visaggio Daniela , Visca Paolo , Ammendola Serena , Battistoni Andrea
Published: September 2024

Limiting the availability of transition metals at infection sites serves as a critical defense mechanism employed by the innate immune system to combat microbial infections.
Pseudomonas aeruginosa
exhibits a remarkable ability to thrive in zinc-deficient environments, facilitated by intricate cellular responses governed by numerous genes regulated by the zinc-responsive transcription factor Zur. Many of these genes have unknown functions, including those within the predicted
PA2911-PA2914
and
PA4063-PA4066
operons. A structural bioinformatics investigation revealed that
PA2911-PA2914
comprises a TonB-dependent outer membrane receptor and inner membrane ABC-permeases responsible for importing metal-chelating molecules, whereas
PA4063-PA4066
contains genes encoding a MacB transporter, likely involved in the export of large molecules. Molecular genetics and biochemical experiments, feeding assays, and intracellular metal content measurements support the hypothesis that
PA2911-PA2914
and
PA4063-PA4066
are engaged in the import and export of the pyochelin-cobalt complex, respectively. Notably, cobalt can reduce zinc demand and promote the growth of
P. aeruginosa
strains unable to import zinc, highlighting pyochelin-mediated cobalt import as a novel bacterial strategy to counteract zinc deficiency. These results unveil an unexpected role for pyochelin in zinc homeostasis and challenge the traditional view of this metallophore exclusively as an iron transporter.

IMPORTANCE

The mechanisms underlying the remarkable ability of
Pseudomonas aeruginosa
to resist the zinc sequestration mechanisms implemented by the vertebrate innate immune system to control bacterial infections are still far from being fully understood. This study reveals that the Zur-regulated gene clusters
PA2911-2914
and
PA4063-PA4066
encode systems for the import and export of cobalt-bound pyochelin, respectively. This proves to be a useful strategy to counteract conditions of severe zinc deficiency since cobalt can replace zinc in many proteins. The discovery that pyochelin may contribute to cellular responses to zinc deficiency leads to a reevaluation of the paradigm that pyochelin is a siderophore involved exclusively in iron acquisition and suggests that this molecule has a broader role in modulating the homeostasis of multiple metals.
Draft genome sequence of
Achromobacter aegrifaciens
BAW48 isolated from arsenic-contaminated tubewell water in Bangladesh
Authors: Hossain Anamica , Hoque M. Nazmul , Bukharid Momtaz Zamila , Hossain M. Anwar , Sultana Munawar
Published: September 2024

We report the draft genome of
Achromobacter aegrifaciens
strain BAW48, a bacterium with a genome size of 6,877,653 bp. This genome comprises gene clusters for arsenic conversion, such as arsenic resistance (
arsHCsO
), arsenite oxidation (
aioBA
), and arsenate reduction (
arsRCDAB
), along with genes for heavy metal and antibiotic resistance.
Draft genome sequence of an arsenotrophic
Achromobacter aegrifaciens
strain isolated from soil in Bangladesh
Authors: Hoque M. Nazmul , Hossain Anamica , Faisal Golam Mahbub , Bukharid Momtaz Zamila , Hossain M. Anwar , Sultana Munawar
Published: September 2024

We report the draft genome of an arsenotrophic
Achromobacter aegrifaciens
BAS32 isolated from arsenic (As)-contaminated soil in Bangladesh. This genome contains several predicted gene clusters for As-conversion, namely, As resistance (
ars
HCsO), arsenite-oxidizing (
aio
BA), and arsenate-reducing (
ars
RCDAB) gene clusters along with antibiotic resistance genes (ARGs).
Genome sequencing of
Enterococcus faecalis
strain 13, an oral strain isolated from C57BL/6 mice
Authors: Vazquez-Munoz Roberto , Russell Jordan T. , Thompson Angela , Dongari-Bagtzoglou Anna
Published: September 2024

Enterococcus faecalis
strain 13 (Ef#13) is a tongue isolate from a C57BL/6 mouse with experimental oropharyngeal candidiasis. Short-read sequencing revealed a genome of 2,767,598 bp with a GC content of 38.4%, and 2,649 genes were predicted.
Preexisting cell state rather than stochastic noise confers high or low infection susceptibility of human lung epithelial cells to adenovirus
Authors: Petkidis Anthony , Suomalainen Maarit , Andriasyan Vardan , Singh Abhyudai , Greber Urs F.
Published: September 2024

Viruses display large variability across all stages of their life cycle, including entry, gene expression, replication, assembly, and egress. We previously reported that the immediate early adenovirus (AdV) E1A transcripts accumulate in human lung epithelial A549 cancer cells with high variability, mostly independent of the number of incoming viral genomes, but somewhat correlated to the cell cycle state at the time of inoculation. Here, we leveraged the classical Luria–Delbrück fluctuation analysis to address whether infection variability primarily arises from the cell state or stochastic noise. The E1A expression was measured by the expression of green fluorescent protein (GFP) from the endogenous E1A promoter in AdV-C5_E1A-FS2A-GFP and found to be highly correlated with the viral plaque formation, indicating reliability of the reporter virus. As an ensemble, randomly picked clonal A549 cell isolates displayed significantly higher coefficients of variation in the E1A expression than technical noise, indicating a phenotypic variability larger than noise. The underlying cell state determining infection variability was maintained for at least 9 weeks of cell cultivation. Our results indicate that preexisting cell states tune adenovirus infection in favor of the cell or the virus. These findings have implications for antiviral strategies and gene therapy applications.

IMPORTANCE

Viral infections are known for their variability. Underlying mechanisms are still incompletely understood but have been associated with particular cell states, for example, the eukaryotic cell division cycle in DNA virus infections. A cell state is the collective of biochemical, morphological, and contextual features owing to particular conditions or at random. It affects how intrinsic or extrinsic cues trigger a response, such as cell division or anti-viral state. Here, we provide evidence that cell states with a built-in memory confer high or low susceptibility of clonal human epithelial cells to adenovirus infection. Results are reminiscent of the Luria–Delbrück fluctuation test with bacteriophage infections back in 1943, which demonstrated that mutations, in the absence of selective pressure prior to infection, cause infection resistance rather than being a consequence of infection. Our findings of dynamic cell states conferring adenovirus infection susceptibility uncover new challenges for the prediction and treatment of viral infections.
A “plus one” strategy impacts replication of felid alphaherpesvirus 1,
Mycoplasma
and
Chlamydia,
and the metabolism of coinfected feline cells
Authors: Klose Sara M. , De Souza David P. , Devlin Joanne M. , Bushell Rhys , Browning Glenn F. , Vaz Paola K.
Published: September 2024

Coinfections are known to play an important role in disease progression and severity. Coinfections are common in cats, but no coinfection studies have investigated the
in vitro
dynamics between feline viral and bacterial pathogens. In this study, we performed co-culture and invasion assays to investigate the ability of common feline bacterial respiratory pathogens,
Chlamydia felis
and
Mycoplasma felis
, to replicate in and invade into Crandell–Rees feline kidney cells. We subsequently investigated how coinfection of these feline cells with each bacterium (
C. felis
or
M. felis
) and the common feline viral pathogen, felid alphaherpesvirus 1 (FHV-1), affects replication of each agent in this cell culture system. We also investigated the metabolic impact of each co-pathogen using metabolomic analysis of infected and coinfected cells.
C. felis
was able to invade and replicate in CRFKs, while
M. felis
had little capacity to invade. During coinfection, FHV-1 replication was minimally affected by the presence of either bacterial pathogen, but bacterial replication kinetics were more affected, particularly in
M. felis
. Both
C. felis
and
M. felis
replicated to higher levels in the presence of a secondary pathogen. Coinfections resulted in reprogramming of the glycolysis pathway, the pentose phosphate pathway, and the tricarboxylic acid cycle. The distinct metabolic profiles of coinfected cells compared to those of cells infected with just one of these three pathogens, as well as the impact of coinfections on viral or bacterial load, suggest strong interactions between these three pathogens and possible synergistic mechanisms enhancing virulence that need further investigation.

IMPORTANCE

In the natural world, respiratory pathogens coexist within their hosts, but their dynamics and interactions remain largely unexplored. Herpesviruses, mycoplasmas, and chlamydias are common and significant causes of acute and chronic respiratory and system disease in animals and people, and these diseases are increasingly found to be polymicrobial. This study investigates how coinfection of feline cells between three respiratory pathogens of cats impact each other as well as the host innate metabolic response to infection. Each of these pathogens have been implicated in the induction of feline upper respiratory tract disease in cats, which is the leading cause of euthanasia in shelters. Understanding how coinfection impacts co-pathogenesis and host responses is critical for improving disease management.
Clinical prediction model for bacterial co-infection in hospitalized COVID-19 patients during four waves of the pandemic
Authors: Elbaz Meital , Moshkovits Itay , Bar-On Tali , Goder Noam , Lichter Yael , Ben-Ami Ronen
Published: September 2024

The reported estimates of bacterial co-infection in COVID-19 patients are highly variable. We aimed to determine the rates and risk factors of bacterial co-infection and develop a clinical prediction model to support early decision-making on antibiotic use. This is a retrospective cohort study conducted in a tertiary-level academic hospital in Israel between March 2020 and May 2022. All adult patients with severe COVID-19 who had a blood or lower respiratory specimen sent for microbiological analyses within 48 h of admission were included. The primary study endpoint was the prevalence of bacterial co-infection at the time of hospital admission. We created a prediction model using the R XGBoost package. The study cohort included 1,050 patients admitted with severe or critical COVID-19. Sixty-two patients (5.9%) had a microbiologically proven bacterial infection on admission. The variables with the greatest impact on the prediction model were age, comorbidities, functional capacity, and laboratory parameters. The model achieved perfect prediction on the training set (area under the curve = 1.0). When applied to the test dataset, the model achieved 56% and 78% specificity with the area under the receiver operating curve of 0.784. The negative and positive predictive values were 0.975 and 0.105, respectively. Applying the prediction model would have resulted in a 2.5-fold increase in appropriate antibiotic use and an 18% reduction in inappropriate use in patients with severe and critical COVID-19. The use of a clinical prediction model can support decisions to withhold empiric antimicrobial treatment at the time of hospital admission without adversely affecting patient outcomes.

IMPORTANCE

Estimates of bacterial coinfection in COVID-19 patients are highly variable and depend on many factors. Patients with severe or critical COVID-19 requiring intensive care unit admission have the highest risk of infection-related complications and death. Thus, the study of the incidence and risk factors for bacterial coinfection in this population is of special interest and may help guide empiric antibiotic therapy and avoid unnecessary antimicrobial treatment. The prediction model based on clinical criteria and simple laboratory tests may be a useful tool to predict bacterial co-infection in patients hospitalized with severe COVID-19.
Role of rectal colonization by third-generation cephalosporin-resistant Enterobacterales on the risk of surgical site infection after hepato-pancreato-biliary surgery
Authors: Rodríguez-Fernández Miguel , Trigo-Rodríguez Marta , Martínez-Baena Darío , Herrero Rocío , Espíndola-Gómez Reinaldo , Martínez Pérez-Crespo Pedro , Vela Alberto Gallego , Torres Eva , García Ana Isabel Aller , León Eva M. , Corzo-Delgado Juan E. , Parra-Membrives Pablo , Merchante Nicolás
Published: September 2024

The impact of third-generation cephalosporin-resistant Enterobacterales (3GCR-E) rectal colonization in the development of subsequent infection after surgery is controversial. In particular, there is a lack of data in the context of hepato-pancreato-biliary (HPB) surgery. The objective of this study was to assess the prevalence of 3GCR-E intestinal carriage among patients undergoing elective HPB resection surgery and its impact on the incidence and etiology of surgical site infections (SSIs). This retrospective cohort study (January 2016–December 2022) was performed at Valme University Hospital (Seville, Spain). The inclusion criteria included (i) 18 years of age or older, (ii) undergoing elective HPB resection surgery, and (iii) availability of a periprocedural surveillance rectal swab culture to detect 3GCR-E. The prevalence of 3GCR-E intestinal carriage at elective HPB resection surgery was assessed, as well as SSI incidence at 30 days and possible associated factors. Two hundred nine patients were included. Eleven (5.3%) patients were colonized by 3GCR-E at baseline. According to 3GCR-E carriage status, 6 (55%) of the carriers developed SSI, whereas this occurred in 50 (25%) of non-carriers (
P
= 0.033). Likewise, the rates of SSI caused specifically by 3GCR-E were 83% (5 of 6) in 3GCR-E carriers and 6% (3 of 50) in non-carriers (
P
< 0.001). After multivariate analyses, 3GCR-E colonization at the time of surgery was identified as an independent predictor for developing SSI (adjusted odds ratio 4.63, 95% confidence interval: 1.177–18.232,
P
= 0.028). Despite a low prevalence of 3GCR-E intestinal carriage at surgery, 3GCR-E rectal colonization is associated with a higher risk of SSI among patients undergoing elective HPB resection surgery, with most SSIs being caused by the colonizing bacteria.

IMPORTANCE

In this Spanish retrospective cohort study, previous 3GCR-E rectal colonization was associated with a higher risk of SSI after hepato-pancreato-biliary resection surgeries. Most of SSIs were caused by the colonizing bacteria, suggesting a rationale for adapted perioperative antibiotic prophylaxis in known 3GCR-E colonized patients.
Selection of marine bacterial consortia efficient at degrading chitin leads to the discovery of new potential chitin degraders
Authors: Meunier Laurence , Costa Rodrigo , Keller-Costa Tina , Cannella David , Dechamps Etienne , George Isabelle F.
Published: September 2024

Chitin degradation is a keystone process in the oceans, mediated by marine microorganisms with the help of several enzymes, mostly chitinases. Sediment, seawater, and filter-feeding marine invertebrates, such as sponges, are known to harbor chitin-degrading bacteria and are presumably hotspots for chitin turnover. Here, we employed an artificial selection process involving enrichment cultures derived from microbial communities associated with the marine sponge
Hymeniacidon perlevis
, its surrounding seawater and sediment, to select bacterial consortia capable of degrading raw chitin. Throughout the artificial selection process, chitin degradation rates and the taxonomic composition of the four successive enrichment cultures were followed. To the best of our knowledge, chitin degradation was characterized for the first time using size exclusion chromatography, which revealed significant shifts in the numbered average chitin molecular weight, strongly suggesting the involvement of endo-chitinases in the breakdown of the chitin polymer during the enrichment process. Concomitantly with chitin degradation, the enrichment cultures exhibited a decrease in alpha diversity compared with the environmental samples. Notably, some of the dominant taxa in the enriched communities, such as
Motilimonas
,
Arcobacter
, and
Halarcobacter
, were previously unknown to be involved in chitin degradation. In particular, the analysis of published genomes of these genera suggests a pivotal role of
Motilimonas
in the hydrolytic cleavage of chitin. This study provides context to the microbiome of the marine sponge
Hymeniacidon perlevis
in light of its environmental surroundings and opens new ground to the future discovery and characterization of novel enzymes of marine origin involved in chitin degradation processes.

IMPORTANCE

Chitin is the second most abundant biopolymer on Earth after cellulose, and the most abundant in the marine environment. At present, industrial processes for the conversion of seafood waste into chitin, chitosan, and chitooligosaccharide (COS) rely on the use of high amounts of concentrated acids or strong alkali at high temperature. Developing bio-based methods to transform available chitin into valuable compounds, such as chitosan and COS, holds promise in promoting a more sustainable, circular bioeconomy. By employing an artificial selection procedure based on chitin as a sole C and N source, we discovered microorganisms so-far unknown to metabolize chitin in the rare microbial biosphere of several marine biotopes. This finding represents a first important step on the path towards characterizing and exploiting potentially novel enzymes of marine origin with biotechnological interest, since products of chitin degradation may find applications across several sectors, such as agriculture, pharmacy, and waste management.
First report of IS
Kpn26
element mediating
mgrB
gene disruption in the ST1 colistin- and carbapenem-resistant
Klebsiella pneumoniae
cluster isolated from a patient with chest infection
Authors: Li Xiaosi , Shen Siquan , Feng Yan , Shen Heping , Hu Fupin , Wu Xiaoyan
Published: September 2024

Colistin is used as a last-line therapy against carbapenem-resistant
Klebsiella pneumoniae
(CRKP). However, colistin resistance in
Klebsiella pneumoniae
is increasingly reported worldwide. This study aims to investigate the instrumental role of insertion sequence (IS) elements in colistin resistance through
mgrB
disruption in
K. pneumoniae
during treatment. Five clinical isolates of CRKP, designated KPN1~KPN5 were collected from the lower respiratory tract of a patient with chest infection before and after treatment with colistin. Antimicrobial susceptibility testing was performed using the broth microdilution method. Whole genome sequencing and bioinformatics were used to analyze the sequence types (STs), resistance genes, and genetic characteristics of the five isolates of
K. pneumoniae
. Antimicrobial susceptibility testing indicated that all five
K. pneumoniae
isolates were resistant to cephalosporins (ceftriaxone, ceftazidime, and cefepime), several carbapenems (imipenem, meropenem), cefoperazone–sulbactam, piperacillin–tazobactam, ciprofloxacin, and fosfomycin, whereas they were sensitive to amikacin and tigecycline. In addition, three of these isolates were resistant to colistin, with minimum inhibitory concentration values of >8 mg/L. Whole genome sequencing revealed that all five
K. pneumoniae
isolates belonged to sequence type 1 (ST1), which shared an identical
bla
KPC-2
. Notably, disruption of
mgrB
by the IS
Kpn26
insertion sequence was shown to be the primary colistin resistance mechanism during the treatment. To our knowledge, this is the first report of IS
Kpn26
element mediating
mgrB
disruption in the ST1 colistin and CRKP obtained from a patient with chest infection in mainland China. This study provides new research ideas to explore the clinical drug resistance mechanism of CRKP and the critical need to monitor and understand resistance mechanisms to preserve the efficacy of last-line antibiotics such as colistin.

IMPORTANCE

Of note, this chapter gives an update on colistin resistance in sequence type 1
Klebsiella pneumoniae
, by focusing on the
mgrB
disrupted by IS
Kpn26
element.
Cefepime-taniborbactam demonstrates potent
in vitro
activity vs
Enterobacterales
with
bla
OXA-48
Authors: Mojica Maria F. , Zeiser Elise T. , Becka Scott A. , Six David A. , Moeck Greg , Papp-Wallace Krisztina M.
Published: September 2024

Taniborbactam (formerly VNRX-5133) is a novel, investigational boronic acid β-lactamase inhibitor. The combination of cefepime (FEP) with taniborbactam is active against
Enterobacterales
carrying class A, B, C, and/or D enzymes. We assessed the activity of FEP-taniborbactam against
Enterobacterales
clinical strains carrying
bla
OXA-48
(
N
= 50, 100%), of which 78% harbored at least one extended-spectrum β-lactamase (ESBL). CLSI-based agar dilution susceptibility testing was conducted using FEP-taniborbactam and comparators FEP, meropenem-vaborbactam (MVB), and ceftazidime-avibactam (CZA). The addition of taniborbactam lowered FEP MICs to the provisionally susceptible range of ≤16 µg/mL; the MIC
90
value decreased from ≥64 µg/mL for FEP to 4 µg/mL for FEP-taniborbactam. Notably, FEP-taniborbactam MIC
50
/MIC
90
values (0.5/4 µg/mL) were lower than those for MVB (1/16 µg/mL) and comparable to those for CZA (0.5/1 µg/mL). Time-kill assays with
E. coli
clinical strains DOV (
bla
OXA-48
,
bla
CTX-M-15
,
bla
TEM-1
, and
bla
OXA-1
) and MLI (
bla
OXA-48
,
bla
VEB
,
bla
TEM-1
, and
bla
CMY-2
) revealed that FEP-taniborbactam at concentrations 1×, 2×, and 4× MIC displayed time-dependent reductions in the number of CFU/mL from 0 to 6 h, and at 4× MIC demonstrated bactericidal activity (3 log
10
reduction in CFU/mL at 24 h). Therefore, taniborbactam in combination with FEP was highly active against this diverse panel of
Enterobacterales
with
bla
OXA-48
and represents a potential addition to our antibiotic arsenal.

IMPORTANCE

OXA-48-like β-lactamases are class D carbapenemases widespread in
Klebsiella pneumoniae
and other
Enterobacterales
and are associated with carbapenem treatment failures. As up to 80% of OXA-48-like positive isolates coproduce extended-spectrum β-lactamases, a combination of β-lactams with broad-spectrum β-lactamase inhibitors is required to counteract all OXA-48-producing strains effectively. Herein, we evaluated the activity of cefepime-taniborbactam against 50 clinical strains producing OXA-48. We report that adding taniborbactam shifted the minimum inhibitory concentration (MIC) toward cefepime’s susceptible range, restoring its antimicrobial activity. Notably, cefepime-taniborbactam MIC
50
/MIC
90
values (0.5/4 µg/mL) were comparable to ceftazidime-avibactam (0.5/1 µg/mL). Finally, time-kill assays revealed sustained bactericidal activity of cefepime-taniborbactam for up to 24 h. In conclusion, cefepime-taniborbactam will be a welcome addition to the antibiotic arsenal to combat
Enterobacterales
producing OXA-48.
Complications resulting from an intragastric balloon in a patient without follow-up and monitoring
Authors: Romero Rodolfo , Biliauws Lore , Roussel Joel , Catheline Jean-Marc
Published: September 2024

The intragastric balloon (IGB) is recognised as a minimally invasive intervention for the treatment of obesity. Here, we detail a rare and life-threatening complication stemming from this procedure. A female patient in her 40s, who had an IGB in situ for 14 months, presented at the emergency department with septic shock characterised by abdominal guarding and emesis. These symptoms were a direct result of IGB-induced bowel obstruction. We emphasise that the patient missed the recommended 6-month removal window, which in our opinion is the decisive cause leading to deflated balloon migration and subsequent complications. In the course of managing multiple critical events, the patient required multiple operations related to the bowel obstruction, numerous nutritional and psychological challenges. Currently, the patient is living with short bowel syndrome, secondary to the chronic intestinal failure, necessitating the administration of parenteral nutrition 6 days per week.
Prescription charge policy acceptance among UK adults with and without long-term health conditions: a mixed-method survey
Authors: Readman Megan Rose , Polden Megan , Brighton Lisa , Oluseye Ayomide , Fairman Ian , Parkinson Ian , Parkinson Caroline , Giebel Clarissa
Published: September 2024

Objectives

Since their introduction in 1952, per-prescribed item charges in England have continually risen. This study investigated the acceptability and impact of per-prescribed item charges, and awareness and use of initiatives designed to reduce prescription charge financial burden (the prescription prepayment certificate (PPC) initiative), in people living with and without long-term health conditions (LTHCs) in the UK.

Design

Cross-sectional mixed-method survey of people with and without an LTHC across the UK.

Participants

381 people, 267 people with an LTHC and 114 people without an LTHC, participated.

Outcome measures

Acceptability and impact of prescription charge policy, awareness and use of the PPC.

Results

Over half (53.2 %) of participants disagreed with current per-prescribed item charges. In most domains, the impact of prescription charges did not differ between people with and without LTHCs. However, people with LTHCs were more likely to report financial burden and deviate from prescribed medication regimes. 35.29% of respondents were aware of the PPC, with people with LTHCs being more likely to be aware of and use this initiative. Qualitative findings indicate perceived inequalities in current policy with themes including (1) the need for re-evaluation; (2) the burden of prescription charges; (3) inconsistencies and inequalities in current policy; and (4) positive reflections of prescription charge policy.

Conclusions

Inconsistencies in current policy and a lack of public support may suggest that a re-evaluation of current policy is required. The lack of difference in the impact of prescription charge policy between people with and without LTHCs indicates that the effects of such policy are not constrained to people with LTHCs. Thus, policy amendments would benefit the wider population. Systematic efforts to increase awareness of the PPC and reduce inequalities in medical exemption criteria are suggested.

Trial registration number

Study protocol and analysis strategy are preregistered on Open Science Framework (https://shorturl.at/IrvnS).
Psychosocial experiences of mothers of preterm babies admitted to the neonatal intensive care unit of the Upper East Regional Hospital, Bolgatanga: a descriptive phenomenological study
Authors: Daliri Dennis Bomansang , Laari Timothy Tienbia , Ayine Alice Atiem , Dei-Asamoa Richard , Volematome Bertha Gibil , Bogee Gillian , Apo-Era Miranda Abisiba , Oppong Solomon Akorley , Abagye Nancy , Jarbaab Maclean , Amoah Moses Abangba , Afaya Agani
Published: September 2024

Introduction

The postnatal period often presents significant psychological and social distress for mothers, a burden that is potentially heightened by having a preterm baby. Mothers of preterm babies face various psychosocial challenges that need to be explored. While some studies have explored the experiences of mothers of preterm babies, there is a need for more context-specific research to inform targeted interventions, especially in resource-constrained settings like northern Ghana. This study aimed to explore the psychosocial experiences of mothers of preterm babies admitted to the neonatal intensive care unit (NICU) of the Upper East Regional Hospital, Ghana.

Methods

This descriptive phenomenological study was conducted in the NICU of the Upper East Regional Hospital in Ghana. Thirteen mothers of preterm babies were purposively sampled and interviewed using a semi-structured interview guide. The interviews were transcribed verbatim and analysed using Colaizzi’s descriptive phenomenological method.

Results

Three themes emerged namely, mothers’ emotional experience, challenges encountered at the NICU and coping strategies. The mothers expressed a range of emotions, from indifference to profound sadness, disbelief, fear and worry, on realising their babies were preterm. Challenges within the NICU were financial constraints and poor NICU facilities while coping strategies included reliance on God, self-reliance and support from family and nurses.

Conclusion

Mothers of preterm babies in the NICU experience significant emotional distress and face numerous challenges. Comprehensive support programmes that address financial, emotional and practical needs are essential to improve outcomes for both mothers and their preterm babies.
Early intravenous high-dose vitamin C in postcardiac arrest shock (VICEPAC): study protocol for a randomised, single-blind, open-label, multicentre, controlled trial
Authors: Chelly Jonathan , Peres Noemie , Sboui Ghada , Maizel Julien , Beuzelin Marion , Nigeon Olivier , Preau Sebastien , Vong Ly Van Phach , Tamion Fabienne , Lambiotte Fabien , Deye Nicolas , Bertrand Thibaut , Behal Hélène , Ducros Laurent , Vinsonneau Christophe
Published: September 2024

Introduction

The high incidence of morbidity and mortality associated with the post-cardiac arrest (CA) period highlights the need for novel therapeutic interventions to improve the outcome of out-of-hospital cardiac arrest (OHCA) patients admitted to the intensive care unit (ICU). The aim of this study is to assess the ability of high-dose intravenous vitamin C (Vit-C) to improve post-CA shock.

Methods and analysis

This is a single-blind, open-label, multicentre, randomised controlled trial, involving 234 OHCA patients with post-CA shock planned to be enrolled in 10 French ICUs. Patients will be randomised to receive standard-of-care (SOC) or SOC with early high-dose intravenous Vit-C administration (200 mg/kg per day, within 6 hours after return of spontaneous circulation, for 3 days). The primary endpoint is the cumulative incidence of vasopressor withdrawal at 72 hours after enrolment, with death considered as a competing event. The main secondary endpoints are neurological outcome, mortality due to refractory shock, vasopressor-free days and organ failure monitored by the sequential organ failure assessment score.

Ethics and dissemination

The study protocol was approved by a French Ethics Committee (EC) on 21 February 2023 (Comité de Protection des Personnes Ile de France 1, Paris, France). Due to the short enrolment period to avoid any delay in treatment, the EC approved the study inclusion before informed consent was obtained. As soon as possible, patient and their relative will be asked for their deferred informed consent. The data from the study will be disseminated through conference presentations and peer-reviewed publications.

Trial registration number

NCT05817851.
Alterations in anterior lens capsule structure and LTBP-2 expression in primary angle-closure glaucoma
Authors: Tian Xiaofeng , Yuan Liyun , Li Liangpin , Yuan Xiaoyong
Published: September 2024

Objective

This study investigated the role of latent-transforming growth factor β-binding protein 2 (LTBP-2) in primary angle-closure glaucoma (PACG) by analysing its expression and the ultrastructure of the anterior lens capsule in PACG patients with age-related cataract (ARC).

Methods

Tissue samples of the anterior lens capsule were collected from patients undergoing cataract phacoemulsification surgery. Patients in the experimental group were diagnosed with primary angle-closure (PAC) combined with ARC (PAC+ARC) and PACG combined with ARC (PACG+ARC). The control group consisted of patients with only ARC. The techniques used included scanning electron microscopy, real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), western blotting and immunofluorescence.

Results

Ultrastructural analysis revealed disordered connections in PAC+ARC, loose connections in PACG+ARC and well-ordered connections in ARC. RT-qPCR and western blotting showed significantly lower LTBP-2 mRNA and protein expression in PAC+ARC and PACG+ARC than in ARC, with PAC+ARC having the lowest levels. Immunofluorescence confirmed these findings, showing varying LTBP-2 fluorescence intensities across groups.

Conclusion

The study identified ultrastructural changes in the anterior lens capsules in PACG accompanied by reduced LTBP-2 expression, especially in PAC+ARC patients. This suggests a potential role for LTBP-2 in PACG development, warranting further investigation.