Characterization of the diversity of type IV secretion system-encoding plasmids in Acinetobacter

The multi-drug resistant pathogen Acinetobacter baumannii has gained global attention as an important clinical challenge. Owing to its ability to survive on surfaces, its capacity for horizontal gene transfer, and its resistance to front-line antibiotics, A. baumannii has established itself as a successful pathogen. Bacterial conjugation is a central mechanism for pathogen evolution. The epidemic multidrug-resistant A. baumannii ACICU harbours a plasmid encoding a Type IV Secretion System (T4SS) with homology to the E. coli F-plasmid, and plasmids with homologous gene clusters have been identified in several A. baumannii sequence types. However the genetic and host strain diversity, global distribution, and functional ability of this group of plasmids is not fully understood. Using systematic analysis, we show that pACICU2 belongs to a group of almost 120 T4SS-encoding plasmids within four different species of Acinetobacter and one strain of Klebsiella pneumoniae from human and environmental origin, and globally distributed across 20 countries spanning 4 continents. Genetic diversity was observed both outside and within the T4SS-encoding cluster, and 47% of plasmids harboured resistance determinants, with two plasmids harbouring eleven. Conjugation studies with an extensively drug-resistant (XDR) strain showed that the XDR plasmid could be successfully transferred to a more divergent A. baumanii, and transconjugants exhibited the resistance phenotype of the plasmid. Collectively, this demonstrates that these T4SS-encoding plasmids are globally distributed and more widespread among Acinetobacter than previously thought, and that they represent an important potential reservoir for future clinical concern.

Comparison of Three Antagonists of Hedgehog Pathway to Promote Skeletal Muscle Regeneration after High Dose Irradiation

The current geopolitical context has brought the radiological nuclear risk to the forefront of concerns. High-dose localized radiation exposure leads to the development of a musculocutaneous radiation syndrome affecting the skin and subcutaneous muscles. Despite the implementation of a gold standard treatment based on an invasive surgical procedure coupled with autologous cell therapy, a muscular defect frequently persists. Targeting the modulation of the Hedgehog (Hh) signaling pathway appears to be a promising therapeutic approach. Activation of this pathway enhances cell survival and promotes proliferation after irradiation, while inhibition by Cyclopamine facilitates differentiation. In this study, we compared the effects of three antagonists of Hh, Cyclopamine (CA), Vismodegib (VDG) and Sonidegib (SDG) on differentiation. A stable cell line of murine myoblasts, C2C12, was exposed to X-ray radiation (5 Gy) and treated with CA, VDG or SDG. Analysis of proliferation, survival (apoptosis), morphology, myogenesis genes expression and proteins production were performed. According to the results, VDG does not have a significant impact on C2C12 cells. SDG increases the expression/production of differentiation markers to a similar extent as CA, while morphologically, SDG proves to be more effective than CA. To conclude, SDG can be used in the same way as CA but already has a marketing authorization with an indication against basal cell cancers, facilitating their use in vivo. This proof of concept demonstrates that SDG represents a promising alternative to CA to promotes differentiation of murine myoblasts. Future studies on isolated and cultured satellite cells and in vivo will test this proof of concept.

Bacterial Pathogenesis: Assessment of Intracellular Positioning of Pathogen-Containing Vacuoles During Infection

Intracellular bacterial pathogens implement a diverse array of strategies to target host cells and establish infection. For vacuolar pathogens, the process of pathogen-containing vacuole movement within host cells, termed intracellular trafficking, is central to both pathogen survival and infection progression. Typically a process mediated by secreted virulence factors that manipulate the host cytoskeletal machinery, internalized pathogen-containing vacuoles traffic to the site of replication to establish a unique replicative niche, and if applicable, traffic back toward the host cell periphery for cell-to-cell spread. As such, the intracellular positioning of pathogen-containing vacuoles represents a fundamental measure of infection progression. Here, we describe a fluorescence microscopy-based method to quantitatively assess bacterial intracellular positioning, using Salmonella enterica serovar Typhimurium infection of epithelial cells as a model. This experimental approach can be modified to study infection in diverse host cell types, and with a broad array of pathogens. The system can also be adapted to examine the kinetics of infection, identify secreted virulence factors that mediate host trafficking, investigate host factors that are targeted by the pathogen for trafficking, and assess functional domains within a virulence factor responsible for mediating the phenotype. Collectively, these tools can provide fundamental insight into the pathogenesis of a diverse array of intracellular bacterial pathogens, and new host factors that are hijacked to mediate infection. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Culture and preparation of host cells Alternate Protocol: Culture and preparation of host cells to assess host factor contribution to bacterial positioning Basic Protocol 2: Infection of epithelial cells with S. Typhimurium Basic Protocol 3: Fluorescence staining for analysis of bacterial positioning Basic Protocol 4: Fluorescence microscopy analysis of bacterial positioning.

P–177 Seminal transferrin levels are linked to embryo utilization rates: a prospective observational study

Study question

What is the impact of seminal transferrin level on intracytoplasmic sperm injection (ICSI) cycle outcomes?

Summary answer

Seminal transferrin levels were positively correlated with embryo utilization rates.

What is known already

Transferrin, a glycoprotein involved in iron transport throughout the body, is produced by various organs such as liver, central nervous system, and testicules. Particularly, Sertoli cells synthesize transferrin to regulate their phagocytotic activity and to ensure iron transportation to germ cells across the blood-testis barrier. In this context, studies have demonstrated the importance of transferrin and iron in spermatogenesis by detecting low levels of seminal transferrin in oligozoospermic men. However, the effects of low seminal transferrin levels on the functionality of spermatozoa and on their ability to maintain embryo development were neither fully investigated nor well understood.

Study design, size, duration

A prospective study was conducted at Al Hadi IVF center, Lebanon, from July 2019 until May 2020. It included 60 infertile couples who have undergone ICSI cycles. Couples were categorized into two groups based on basic semen parameters assessed according to the World Health Organization recommendations 2010: normozoospermia group (n = 30 couples) and non-normozoospermia group (n = 30 couples). In this study, non-normozoospermia was defined as the presence of at least one abnormality in basic semen parameters.

Participants/materials, setting, methods

In this prospective study, the inclusion criteria were: couples where women had 38 years old or less at the time of ICSI, using fresh gametes, and using ejaculated semen. Moreover, women with premature ovarian failure, obese women, and ICSI cycles with embryo biopsy were excluded. Seminal levels of transferrin and iron were measured using Cobas 400 plus (Roche Diagnostics). Fertilization rates, embryo utilization rates, and live birth rates were calculated.

Main results and the role of chance

There were no statistically significant differences in the characteristics of the study population (maternal age, paternal age, maternal body mass index (BMI), paternal BMI, maternal and paternal tobacco intake, maternal and paternal alcohol consumption, number of collected oocytes and number of embryos transferred) (p > 0.05) between normozoospermia and non-normozoospermia groups. A statistically significant difference was detected in seminal transferrin levels (mg/dl) (2(0–23) vs. 1(0–6), p < 0.02) between the two groups. Interestingly, these transferrin levels were positively correlated with sperm concentration (R = 0.29; p = 0.03). In parallel, no statistically significant difference was observed between groups concerning seminal iron levels (µg/dl) (51(21.1–100.8) vs. 48.6 (11–85.7); p = 0.33). Furthermore, there was no statistically significant difference in the fertilization rates (%) between the two groups (74.2 vs. 74.8; p = 0.95). Of particular interest, a statistically significant positive correlation was detected between seminal transferrin levels and embryo utilization rates (R = 0.33; p = 0.013). In contrast, the live birth rates (%) were not different between groups (54.54 vs. 58.3; p = 0.77) and were not correlated with seminal transferrin levels (R=–0.3; p = 0.16).

Limitations, reasons for caution

A prospective study with a larger sample size is required to confirm the effects of seminal transferrin levels on assisted reproductive technology outcomes.

Wider implications of the findings: Deciphering the molecular mechanism by which transferrin level may influence spermatozoa quality and subsequently embryo development will be of paramount importance. Moreover, understanding the reasons behind the altered seminal transferrin level and testing several strategies to restore it, may enhance spermatozoa quality and increase pregnancy chances.

Trial registration number

Not applicable

Role of blood derived cell fractions, temperature and sample transport on gene expression-based biological dosimetry

PURPOSE

For triage purposes following a nuclear accident or a terrorist event, gene expression biomarkers in blood have been demonstrated to be good bioindicators of ionizing radiation (IR) exposure and can be used to assess the dose received by exposed individuals. Many IR-sensitive genes are regulated by the DNA damage response pathway, and modulators of this pathway could potentially affect their expression level and therefore alter accurate dose estimations. In the present study, we addressed the potential influence of temperature, sample transport conditions and the blood cell fraction analyzed on the transcriptional response of the following radiation-responsive genes: FDXR, CCNG1, MDM2, PHPT1, APOBEC3H, DDB2, SESN1, P21, PUMA, and GADD45.

MATERIALS AND METHODS

Whole blood from healthy donors was exposed to a 2 Gy X-ray dose with a dose rate of 0.5 Gy/min (output 13 mA, 250 kV peak, 0.2 mA) and incubated for 24 h at either 37, 22, or 4 °C. For mimicking the effect of transport conditions at different temperatures, samples incubated at 37 °C for 24 h were kept at 37, 22 or 4 °C for another 24 h. Comparisons of biomarker responses to IR between white blood cells (WBCs), peripheral blood mononuclear cells (PBMCs) and whole blood were carried out after a 2 Gy X-ray exposure and incubation at 37 °C for 24 hours.

RESULTS

Hypothermic conditions (22 or 4 °C) following irradiation drastically inhibited transcriptional responses to IR exposure. However, sample shipment at different temperatures did not affect gene expression level except for SESN1. The transcriptional response to IR of specific genes depended on the cell fraction used, apart from FDXR, CCNG1, and SESN1.

CONCLUSION

In conclusion, temperature during the incubation period and cell fraction but not the storing conditions during transport can influence the transcriptional response of specific genes. However, FDXR and CCNG1 showed a consistent response under all the different conditions tested demonstrating their reliability as individual biological dosimetry biomarkers.

Experiences of humanitarian assistance programs with corporate funding

Background

Dwindling governmental funding for widespread natural disasters and armed conflicts have attracted corporate funding for humanitarian assistance. Although such funding has allowed expansion of humanitarian programs and capacity building, evaluations of such partnerships are rare and focus only on management aspects, without attention to possible influences on the organizations themselves and the populations they serve. Given the well-established conflicts of interest of corporations and their adverse influence on public health, an assessment of industry funding to humanitarian assistance is necessary to identify potential violations and harms.

Methods

The research explores the experiences and views of a sample of humanitarian agencies in Lebanon which serve refugee populations about corporate funding and influences on their programs. In-depth interviews with international and local humanitarian agency representatives in Lebanon were conducted and analyzed by thematic analysis.

Results

Findings indicate perceived advantages with financial assistance, flexible agendas and mutual learning. Meanwhile, challenges fall in project coordination, implementation, and the lack of attention of the private sector to the work ethics with vulnerable populations. Also, this collaboration could impact refugees positively or negatively depending on the type of corporations, their branding and how they are perceived by the populations served. Organizations trust that their processes of detection and reporting are an impervious firewall against conflicts of interest.

Conclusions

Corporate power expressed through funding to humanitarian agencies may influence the decision making and the implementation of the programs for humanitarian assistance. The study highlights the need for critical thinking about corporate funding, and creating opportunities for discussion about this issue for humanitarian agencies.

Key messages

Industry conflicts of interest on public health are well-established, but understudied in humanitarian assistance programs. Corporate funding for humanitarian assistance may hide potential conflicts of interest for the corporation.

Retinal dystrophies with bull's-eye maculopathy along with negative ERGs

PURPOSE

The aim of this study was to examine the ophthalmological characteristics and genotypes of patients with congenital retinal pathologies, who display a bull's-eye maculopathy in the fundus, along with a negative scotopic electroretinogram.

METHODS

We analysed the results of five patients showing both a bull's-eye maculopathy, as well as a negative scotopic ERG evoked by a bright flash. Their median age was 39 years (range 11-63 years): three males and two females. All underwent a comprehensive examination with determination of distant visual acuity (ETDRS) and recording of the full-field ERG (scotopic and photopic). Fundus, OCT, and FAF images were obtained, the kinetic visual field was determined, and colour vision (D-15) was tested in most patients. Targeted gene panel sequencing was performed on peripheral blood.

RESULTS

One patient carried a homozygous ABCA4 mutation and an additional heterozygous variant in CRX. Two of the five patients were shown to have a heterozygous mutation in the CRX gene, one of whom had an additional heterozygous ABCA4 mutation. Two patients had the common heterozygous mutation c.2413G>A;p.Arg838His in GUCY2D. In all of the patients, there was a reduction in the amplitude of the b-wave with a regular a-wave amplitude in the scotopic bright-flash ERG.

CONCLUSIONS

The five patients with bull's-eye maculopathy along with a negative ERG had differing genotypes. Mutations were found in the CRX gene (2 patients), the ABCA4 gene (1 patient), and the GUCY2D gene (2 patients).

Hypotrichosis with cone-rod dystrophy in a patient with cadherin 3 (CDH3) mutation

PURPOSE

To investigate a very rare case of hypotrichosis with cone-rod dystrophy caused by a P-cadherin CDH3 mutation.

METHODS

A 16-year-old Syrian girl was examined at age 9 and 14 years with an ophthalmological examination, fundus imaging, OCT and electrophysiological recordings (ERG and PERG). A disease-targeted gene panel sequencing was performed.

RESULTS

Fundus images showed pigmentations at the posterior eye pole to the mid periphery, as well as vessel tortuosity. OCT images revealed a loss of the outer retinal segments and IS/OS in the central macula. The scotopic and photopic ERGs showed moderately reduced amplitudes at age 9 years that became severely reduced at age of 14 years. The PERG was undetectable at age 9 years. In color vision testing, protan-deutan confusion errors occurred. Gene panel analysis revealed one homozygous mutation in CDH3 (c.1508G>A; p.Arg503His).

CONCLUSION

This case shows that a CDH3 mutation besides macula dystrophy can cause widespread cone-rod dystrophy with hypotrichosis without any other pathology besides hypoplastic nails. This points to a common pathway of hair growth and photoreceptor development that can be disturbed by a CDH3 mutation (c.1508G>A; p.Arg503His) located in the EC4 repeat region of the gene.

Controlled-release oxycodone improves pain management after uterine artery embolisation for symptomatic fibroids

AIM

To evaluate if pre- and post-procedure administration of controlled-release oxycodone (CRO) in combination with standard analgesia improves pain control and decreases the amount of required post-procedure opioids in uterine fibroid embolisation (UFE).

MATERIALS AND METHODS

Between January 2009 and March 2010, 60 consecutive women were prospectively randomised in two groups for UFE: the control group, in which 30 patients underwent the standard anaesthetic procedure and the CRO group, in which 30 patients underwent the standard anaesthetic procedure with the addition of CRO. Age, pain, nausea/vomiting, fibroid volume, length of hospital stay, and use and dose of morphine received via the patient-controlled analgesia (PCA) device in both groups were evaluated to compare the two methods of pain control. Fibroid volume as measured at magnetic resonance imaging (MRI) was evaluated for correlation with post-embolisation pelvic pain over a period of 24 hours.

RESULTS

A significant difference was seen in the pain scores at 24 hours (p=0.029), with less pain in the CRO group. More patients from the control group required morphine (p=0.017), and at higher levels (p=0.130). Pruritus was lower in patients of the CRO group, probably because they received less morphine (p=0.029). No correlation was seen between leiomyoma volume and pain levels over 24 hours (Spearman's ρ=0.02; p=0.881). Length of hospital stay was not different between the two groups.

CONCLUSION

The addition of CRO to standard analgesia for UFE provides more effective analgesia, with a reduction in pain scores in 24 hours, less morphine use, and decreased side effects, mainly pruritus.