Qualitative interview study exploring the perspectives of pregnant women on participating in controlled human infection research in the UK

INTRODUCTION

Pregnant women have been historically excluded from interventional research. While recent efforts have been made to improve their involvement, there remains a disparity in the evidence base for treatments available to pregnant women compared with the non-pregnant population. A significant barrier to the enrolment of pregnant women within research is risk perception and a poor understanding of decision-making in this population.

OBJECTIVE

Assess the risk perception and influences on decision-making in pregnant women, when considering whether to enrol in a hypothetical interventional research study.

DESIGN

Semistructured interviews were undertaken, and thematic analysis was undertaken of participant responses.

PARTICIPANTS

Twelve pregnant women were enrolled from an antenatal outpatient clinic.

RESULTS

Participants were unanimously positive about enrolling in the proposed hypothetical interventional study. Risk perception was influenced by potential risks to their fetus and their previous experiences of healthcare and research. Participants found the uncertainty in quantifying risk for new research interventions challenging. They were motivated to enrol in research by altruism and found less invasive research interventions more tolerable.

CONCLUSION

It is vital to understand how pregnant women balance the perceived risks and benefits of interventional research. This may help clinicians and scientists better communicate risk to pregnant women and address the ongoing under-representation of pregnant women in interventional research.

A Questionnaire-based Study Exploring Participant Perspectives in a Perinatal Human Challenge Trial

BACKGROUND

Pregnant women have historically been excluded from most medical research, including human challenge studies. The proof-of-concept Lactamica 9 human challenge study investigated whether nasal inoculation of pregnant women with commensal bacteria leads to horizontal transmission to the neonate. Given the unique practical and ethical considerations of both human challenge studies and interventional research involving pregnant women and their newborns, we sought to investigate the motivations, concerns and experiences of these volunteers.

METHODS

Pre- and post-participation questionnaires were given to all participants in the Lactamica 9 study. These fully anonymized qualitative and Semi-quantitative questionnaires used forced Likert scales, word association and free-text questions.

RESULTS

Pre- and post-participation questionnaires were completed by 87.1% (27/31) and 62.5% (15/24) of eligible participants, respectively. Almost all pre-participation respondents agreed with altruistic motivations for participation, and most concerns were related to discomfort from study procedures, with few concerned about the theoretical risks of inoculation to themselves (5/27; 18.5%) or their baby (6/27; 22.2%). Participants most frequently associated the study intervention with the terms "bacteria," "natural," "protective" and "safe." For the post-participation questionnaire, 93.3% (14/15) found all study procedures acceptable, and qualitative feedback was almost entirely positive, with particular emphasis on the research team's flexibility, approachability and friendliness.

CONCLUSIONS

The successful completion of the Lactamica 9 study demonstrates that human challenge research in healthy pregnant women can be acceptable and feasible. Participants' initial concerns of potential discomfort were outweighed by predominantly altruistic motivations and perception of the intervention as "natural."

Microbiotoxicity: antibiotic usage and its unintended harm to the microbiome

PURPOSE OF REVIEW

Antibiotic use is associated with development of antimicrobial resistance and dysregulation of the microbiome (the overall host microbial community). These changes have in turn been associated with downstream adverse health outcomes. This review analyses recent important publications in a rapidly evolving field, contextualizing the available evidence to assist clinicians weighing the potential risks of antibiotics on a patient's microbiome.

RECENT FINDING

Although the majority of microbiome research is observational, we highlight recent interventional studies probing the associations between antibiotic use, microbiome disruption, and ill-health. These studies include germ-free mouse models, antibiotic challenge in healthy human volunteers, and a phase III study of the world's first approved microbiome-based medicine.

SUMMARY

The growing body of relevant clinical and experimental evidence for antibiotic-mediated microbiome perturbation is concerning, although further causal evidence is required. Within the limits of this evidence, we propose the novel term 'microbiotoxicity' to describe the unintended harms of antibiotics on a patient's microbiome. We suggest a framework for prescribers to weigh microbiotoxic effects against the intended benefits of antibiotic use.

Artificial intelligence, machine learning and deep learning: Potential resources for the infection clinician

BACKGROUND

Artificial intelligence (AI), machine learning and deep learning (including generative AI) are increasingly being investigated in the context of research and management of human infection.

OBJECTIVES

We summarise recent and potential future applications of AI and its relevance to clinical infection practice.

METHODS

1617 PubMed results were screened, with priority given to clinical trials, systematic reviews and meta-analyses. This narrative review focusses on studies using prospectively collected real-world data with clinical validation, and on research with translational potential, such as novel drug discovery and microbiome-based interventions.

RESULTS

There is some evidence of clinical utility of AI applied to laboratory diagnostics (e.g. digital culture plate reading, malaria diagnosis, antimicrobial resistance profiling), clinical imaging analysis (e.g. pulmonary tuberculosis diagnosis), clinical decision support tools (e.g. sepsis prediction, antimicrobial prescribing) and public health outbreak management (e.g. COVID-19). Most studies to date lack any real-world validation or clinical utility metrics. Significant heterogeneity in study design and reporting limits comparability. Many practical and ethical issues exist, including algorithm transparency and risk of bias.

CONCLUSIONS

Interest in and development of AI-based tools for infection research and management are undoubtedly gaining pace, although the real-world clinical utility to date appears much more modest.

Effect of colonisation with Neisseria lactamica on cross-reactive anti-meningococcal B-cell responses: a randomised, controlled, human infection trial

BACKGROUND

Pharyngeal colonisation by the commensal bacterium Neisseria lactamica inhibits colonisation by Neisseria meningitidis and has an inverse epidemiological association with meningococcal disease. The mechanisms that underpin this relationship are unclear, but could involve the induction of cross-reactive immunity. In this study, we aimed to evaluate whether colonisation with N lactamica induces N lactamica-specific B-cell responses that are cross-reactive with N meningitidis.

METHODS

In this randomised, placebo-controlled, human infection trial at University Hospital Southampton Clinical Research Facility (Southampton, UK), healthy adults aged 18-45 years were randomly assigned (2:1) to receive intranasal inoculation with either 105 colony-forming units of N lactamica in 1 mL phosphate-buffered saline (PBS) or 1 mL PBS alone. Participants and researchers conducting participant sampling and immunological assays were masked to allocation. The primary endpoint was the frequency of circulating N lactamica-specific plasma cells and memory B cells after N lactamica inoculation (day 7-28) compared with baseline values (day 0), measured using enzyme-linked immunospot assays. The secondary endpoint was to measure the frequency of N meningitidis-specific B cells. In a second study, we measured the effect of duration of N lactamica colonisation on seroconversion by terminating carriage at either 4 days or 14 days with single-dose oral ciprofloxacin. The studies are now closed to participants. The trials are registered with ClinicalTrials.gov, NCT03633474 and NCT03549325.

FINDINGS

Of 50 participants assessed for eligibility between Sept 5, 2018, and March 3, 2019, 31 were randomly assigned (n=20 N lactamica, n=11 PBS). Among the 17 participants who were colonised with N lactamica, the median baselines compared with peak post-colonisation N lactamica-specific plasma-cell frequencies (per 105 peripheral blood mononuclear cells) were 0·0 (IQR 0·0-0·0) versus 5·0 (1·5-10·5) for IgA-secreting plasma cells (p<0·0001), and 0·0 (0·0-0·0) versus 3·0 (1·5-9·5) for IgG-secreting plasma cells (p<0·0001). Median N lactamica-specific IgG memory-B-cell frequencies (percentage of total IgG memory B cells) increased from 0·0024% (0·0000-0·0097) at baseline to 0·0384% (0·0275-0·0649) at day 28 (p<0·0001). The frequency of N meningitidis-specific IgA-secreting and IgG-secreting plasma cells and memory B cells also increased signficantly in participants who were colonised with N lactamica. Upper respiratory tract symptoms were reported in ten (50%) of 20 participants who were inoculated with N lactamica and six (55%) of 11 participants who were inoculated with PBS (p>0·99). Three additional adverse events (two in the N lactamica group and one in the PBS group) and no serious adverse events were reported. In the second study, anti-N lactamica and anti-N meningitidis serum IgG titres increased only in participants who were colonised with N lactamica for 14 days.

INTERPRETATION

Natural immunity to N meningitidis after colonisation with N lactamica might be due to cross-reactive adaptive responses. Exploitation of this microbial mechanism with a genetically modified live vector could protect against N meningitidis colonisation and disease.

FUNDING

Wellcome Trust, Medical Research Council, and NIHR Southampton Biomedical Research Centre.

A systematic review and meta-analysis of the prevalence of human cytomegalovirus shedding in seropositive pregnant women

The detection of human cytomegalovirus (HCMV) in an individual's bodily fluid by culture techniques or through HCMV DNA detection by polymerase chain reaction, is known as HCMV shedding. Human cytomegalovirus shedding has the potential to transmit HCMV infection, where an individual can become infected with HCMV through contact with the bodily fluid of another individual containing HCMV. Human cytomegalovirus shedding can occur in primary infection and in non-primary infection for individuals with prior infection (HCMV seropositive). Human cytomegalovirus infection causes few or no symptoms in a pregnant woman, but can cause significant harm to her foetus if congenital CMV (cCMV) infection occurs. The association between HCMV shedding in HCMV seropositive pregnant women and the vertical transmission of HCMV to result in cCMV infection is poorly investigated, challenged by a limited understanding of the distribution of HCMV shedding in HCMV seropositive pregnant women. We systematically reviewed the published literature to describe the prevalence of HCMV shedding in HCMV seropositive women during pregnancy up to delivery. This analysis identified nine studies that met our eligibility criteria. In these studies, the prevalence of HCMV shedding in any bodily fluid of HCMV seropositive women during pregnancy and at delivery ranged from 0% to 42.5%. A meta-analysis, performed on six of the nine studies with suitable sample sizes, estimated a pooled prevalence of 21.5% [95% CI 12.7%,30.3%]. To our knowledge, this is the first review to systematically search the literature to summarise the prevalence of HCMV shedding in HCMV seropositive pregnant women. These estimates can help in the development of disease burden models and therapeutic or preventative strategies against cCMV infection in the context of non-primary maternal HCMV infection.

Controlled human infection with Neisseria lactamica in late pregnancy to measure horizontal transmission and microbiome changes in mother-neonate pairs: a single-arm interventional pilot study protocol

INTRODUCTION

Infant upper respiratory microbiota are derived partly from the maternal respiratory tract, and certain microbiota are associated with altered risk of infections and respiratory disease. Neisseria lactamica is a common pharyngeal commensal in young children and is associated with reduced carriage and invasive disease by Neisseria meningitidis. Nasal inoculation with N. lactamica safely and reproducibly reduces N. meningitidis colonisation in healthy adults. We propose nasal inoculation of pregnant women with N. lactamica, to establish if neonatal pharyngeal colonisation occurs after birth, and to characterise microbiome evolution in mother-infant pairs over 1 month post partum.

METHODS AND ANALYSIS

20 healthy pregnant women will receive nasal inoculation with N. lactamica (wild type strain Y92-1009) at 36-38 weeks gestation. Upper respiratory samples, as well as optional breastmilk, umbilical cord blood and infant venous blood samples, will be collected from mother-infant pairs over 1 month post partum. We will assess safety, N. lactamica colonisation (by targeted PCR) and longitudinal microevolution (by whole genome sequencing), and microbiome evolution (by 16S rRNA gene sequencing).

ETHICS AND DISSEMINATION

This study has been approved by the London Central Research Ethics Committee (21/PR/0373). Findings will be published in peer-reviewed open-access journals as soon as possible.

TRIAL REGISTRATION NUMBER

NCT04784845.

Controlled human infection with Neisseria lactamica induces B-cell responses that are cross-reactive with Neisseria meningitidis

Neisseria lactamica (Nlac) is a commensal of the human oropharynx. Colonisation with Nlac significantly reduces colonisation by N. meningitidis (Nmen). We hypothesised that cross-reactive adaptive cellular immune responses were responsible for this effect.

31 volunteers were inoculated intra-nasally with 105 colony-forming units of Nlac or vehicle control. Nlac/Nmen colonisation status was assessed at baseline and 7-, 14- and 28-days post-inoculation. Nlac/Nmen-specific plasma cells (PCs)/memory B-cells were quantified in PBMCs at all time points using ELISpot assays.

Amongst Nlac-colonised volunteers (n=17), Nlac-specific PC frequencies/2×105 PBMCs increased significantly. Median baseline vs. post-colonisation peak Nlac-specific PC frequencies were 0 (range 0–0.5) vs. 2 (0–31) for IgM, 0 (0–1) vs. 5 (0–20.5) for IgA, and 0 (0–1) vs. 3 (0–27) for IgG (all p&lt;0.0001). Nlac-specific IgG memory B-cell frequencies also increased significantly from baseline to day 28 (0.000% vs. 0.04%, p&lt;0.0001). Interestingly, there was also a significant increase in IgM, IgA and IgG Nmen-specific PCs amongst Nlac-colonised volunteers. Median baseline vs. post-colonisation peak Nmen-specific PC frequencies were 0 (0–0) vs. 0 (0–30) for IgM, 0 (0–1) vs. 0.5 (0–8.5) for IgA, and 0 (0–0.5) vs. 0.5 (0–10) for IgG (all p≤0.01). There was no induction of Nlac-specific PCs/memory B-cells in the control group (n=10).

These data suggest that the previously observed protective effect of Nlac on Nmen colonisation may have an immunological basis. We plan to assess the frequency/effector phenotype of Nlac-specific CD4+ memory T-cells following Nlac colonisation and hypothesise that cross-reactive CD4+ memory T-cells directed towards Nmen will be Th17.

An acute presentation of haemophagocytic lymphohistiocytosis due to visceral leishmaniasis in a British adult returning traveller

A 62-year old British Caucasian woman normally resident in Spain presented with fever and pancytopaenia after returning to the UK. Her symptoms persisted despite broad-spectrum antibiotics, and she gradually became confused, hypotensive and progressively more pancytopaenic. Imaging demonstrated hepatosplenomegaly, and a bone marrow aspirate confirmed a diagnosis of haemophagocytic lymphohistiocytosis (HLH). Bone marrow polymerase chain reaction (PCR) and blood serology were both positive for Leishmania donovani, consistent with visceral leishmaniasis (VL). Following treatment with dexamethasone and amphotericin, she improved clinically and biochemically, and was able to return to Spain. Fever in the returning traveller is a common acute medical presentation. Although HLH and VL are rare diagnoses, both carry a very high mortality rate if undiagnosed and untreated.

Painful lymphadenopathy due to silicone breast implant rupture following extensive global air travel

A 25-year-old Caucasian flight attendant with an extensive travel history presented with night sweats, fevers, weight loss and axillary and supraclavicular lymphadenopathy. Apart from surgical breast augmentation, she had no past medical or surgical history. She was anaemic, leucopenic and lymphopenic, and a broad infection screen was negative. Cross-sectional imaging revealed ipsilateral silicone breast implant rupture, with leaking of implant contents into the surrounding tissue. Histological examination of an axillary lymph node core biopsy confirmed the diagnosis of silicone lymphadenopathy. This case illustrates the broad differential for acute painful lymphadenopathy in the context of global travel, and the use of targeted infection testing, early cross-sectional imaging and biopsy to arrive at an unexpected diagnosis.

Cassandra's prophecy: medic or mother? Exploring the relevance of age-related fertility decline to women in medicine

This commentary presents a response to 'Cassandra's prophecy' from the perspective of a final-year medical student, in an attempt to gauge the particular relevance of age-related fertility decline to female doctors. Women in the UK are increasingly trying to have children at an older age, with a resultant rise in the incidence of age-related fertility decline and obstetric problems. The literature suggests that the trend towards older motherhood is seen particularly among highly educated women, but that such women lack sufficient knowledge about how fertility and obstetric outcomes decline with age. Recent data indicate that female doctors have children significantly later than women in the general population, but are overall no more likely to remain childless. However, there is significant variation between different specialties; for instance, female surgeons have children significantly later and are more likely to be childless by age 35, as compared with both male surgeons and female doctors in other specialties. This commentary explores various explanations for and implications of these data, in the context of recent changes in NHS workforce gender demographics.

The politics of human embryo research and the motivation to achieve PGD

This article reports a historical study of factors influencing the achievement of clinical preimplantation genetic diagnosis (PGD) in 1990, 22 years after its first demonstration in animals. During the 1970s, research on PGD continued in large farm animals, but serious interest in human PGD was not evident until 1986. First, interest in PGD during the 1970s waned with the advent of prenatal testing, which for gynaecologists was clinically more familiar, technically simpler and ethically less challenging than IVF. Indeed, IVF was viewed with widespread suspicion until the first IVF births in 1978. Second, interest in clinical PGD was stimulated by the UK Parliamentary reaction against human embryo research that greeted the Warnock Report in 1984. This hostility led scientists to initiate a pro-research campaign, further galvanized in 1985 by MP Enoch Powell’s bid to ban such research. However, while Powell abhorred embryo research, he approved of PGD, a stance that divided the anti-research lobby. Accordingly, the campaigners for research emphasized that it was needed to achieve PGD. Powell demanded evidence of such projects and PGD research increased from 1986. It is concluded that UK political debates on embryo research played a critical role in stimulating the achievement of clinical PGD.

Human pregnancies following preimplantation genetic diagnosis (PGD) for embryo sex were announced in 1990, 22 years after the technique was pioneered in animals. PGD in humans required not only technological advances, such as IVF and sensitive diagnostic tests, but also the motivation to develop and apply them. Our historical analysis shows that, although research on PGD continued in large farm animals during the 1970s, and techniques of the required sensitivity were developed on mouse embryo models, interest in clinical PGD was not evident until 1986. Two factors stimulated this sudden change in motivation. First, interest in PGD was depressed during the 1970s by the advent of prenatal diagnostic techniques, which for gynaecologists were clinically, technically and ethically less challenging than IVF. IVF was then regarded with a suspicion that only started to wane in the early 1980s following the first IVF births. Second, the UK Parliamentary reaction against human embryo research that greeted the Warnock Report in 1984 provided a positive stimulus to clinical PGD by prompting scientists to form a pro-research lobby, which was further galvanized in early 1985 by MP Enoch Powell’s almost-successful bid to ban human embryo research. We show that while Powell abhorred embryo research, he approved of PGD, a stance that fractured the unity of the anti-research lobby. Accordingly, the pro-research lobby emphasized that embryo research was needed to achieve PGD. Powell demanded evidence of such projects, thereby, we argue, stimulating PGD research from 1986. Our evidence shows that UK political debates about PGD played a critical role in stimulating the achievement of PGD clinically.