Role of vertical and horizontal microbial transmission of antimicrobial resistance genes in early life: insights from maternal-infant dyads

Real-world antibiotic utilization during pregnancy in Italy: a multiregional retrospective population-based study

BACKGROUND

Exposure to antibiotics during pregnancy is frequent, despite the limited evidence derived from clinical trials. Drug utilization studies could improve knowledge on utilization of these medications during this critical period. In this context, the present study aimed to describe antibiotic exposure during pregnancy in Italy at both national and regional levels.

METHODS

This retrospective population-based study involved a cohort of women who gave birth from 2016 to 2018 and were residents of one of the following Italian regions: Lombardy, Veneto, Emilia-Romagna, Tuscany, Umbria, Lazio, Apulia or Sardinia. A series of sociodemographic and clinical characteristics were retrieved from regional healthcare databases. The prevalence of the use of antibiotics was estimated in nine trimesters, which were divided into three different periods: pre- pregnancy (-III, -II, -I) during pregnancy (I, II, III) and post-pregnancy (+ I, + II, + III). Analyses were stratified by region and by prenatal invasive diagnostic performed.

RESULTS

A total of 449,012 women were included in the study, of whom more than 37% were aged ≥ 35 years at birth. The overall prevalence rates of antibiotic use in the study cohort were 33.9% pre-pregnancy (per trimester: -III = 14.3%, -II = 14.5%, -I = 14.5%), 31.8% during pregnancy (per trimester: I = 12.0%, II = 16.0%, III = 11.4%) and 29.3% post-pregnancy (per trimester: + I = 15.3%, + II = 9.7%; + III = 11.0%). The regions with the lowest usage pre-, during and post-pregnancy were Lombardy (29.7%, 26.1%, 28.0%) and Veneto (28.8%, 26.4%, 25.5%), whereas Apulia reached the highest values (45.6%, 41.6%, 38.3%). The highest peaks during pregnancy were reached by Umbria (25.8%), Latium (24.1%) and Apulia (21.4%). Women who underwent chorionic villus sampling and those who underwent amniocentesis registered a peak during trimester I (25%) and trimester II (41%), respectively. These peaks were in line with the timing of the invasive prenatal diagnostic procedures.

CONCLUSIONS

The use of antibiotics during pregnancy in Italy was in line with other European countries, reflecting national and international guidelines. However, a certain level of misuse of specific antibiotics and different utilization rates across the regions were observed. Continuous monitoring of long- and short-term outcomes associated with exposure to antibiotics during pregnancy may contribute to reducing excessive utilization and improving the diffusion of more appropriate procedures and practices.

Unravelling AMR dynamics in the rumenofaecobiome: Insights, challenges and implications for One Health

Antimicrobial resistance (AMR) is a critical global threat to human, animal and environmental health, exacerbated by horizontal gene transfer (HGT) via mobile genetic elements. This poses significant challenges that have a negative impact on the sustainability of the One Health approach, hindering its long-term viability and effectiveness in addressing the interconnectedness of global health. Recent studies on livestock animals, specifically ruminants, indicate that culturable ruminal bacteria harbour AMR genes with the potential for HGT. However, these studies have focused predominantly on using the faecobiome as a proxy to the rumen microbiome or using easily isolated and culturable bacteria, overlooking the unculturable population. These unculturable microbial groups could have a profound influence on the rumen resistome and AMR dynamics within livestock ecosystems, potentially holding critical insights for advanced understanding of AMR in One Health. In order to address this gap, this review of current research on the burden of AMR in livestock was undertaken, and it is proposed that combined study of the rumen microbiome and faecobiome, termed the 'rumenofaecobiome', should be performed to enhance understanding of the risks of AMR in ruminant livestock. This review discusses the complexities of the rumen microbiome and the risks of AMR transmission in this microbiome in a One Health context. AMR transmission dynamics and methodologies for assessing the risks of AMR in livestock are summarized, and future considerations for researching the impact of AMR in the rumen microbiome and the implications within the One Health framework are discussed.

Human microbiome acquisition and transmission

As humans, we host personal microbiomes intricately connected to our biology and health. Far from being isolated entities, our microbiomes are dynamically shaped by microbial exchange with the surroundings, in lifelong microbiome acquisition and transmission processes. In this Review, we explore recent studies on how our microbiomes are transmitted, beginning at birth and during interactions with other humans and the environment. We also describe the key methodological aspects of transmission inference, based on the uniqueness of the building blocks of the microbiome - single microbial strains. A better understanding of human microbiome transmission will have implications for studies of microbial host regulation, of microbiome-associated diseases, and for effective microbiome-targeting strategies. Besides exchanging strains with other humans, there is also preliminary evidence we acquire microorganisms from animals and food, and thus a complete understanding of microbiome acquisition and transmission can only be attained by adopting a One Health perspective.

Cutting-edge tools for unveiling the dynamics of plasmid-host interactions

The plasmid-mediated transfer of antibiotic resistance genes (ARGs) in complex microbiomes presents a significant global health challenge. This review examines recent technological advancements that have enabled us to move beyond the limitations of culture-dependent detection of conjugation and have enhanced our ability to track and understand the movement of ARGs in real-world scenarios. We critically assess the applications of single-cell sequencing, fluorescence-based techniques and advanced high-throughput chromatin conformation capture (Hi-C) approaches in elucidating plasmid-host interactions at unprecedented resolution. We also evaluate emerging techniques such as CRISPR-based phage engineering and discuss their potential for developing targeted strategies to curb ARG dissemination. Emerging data derived from these technologies have challenged our previous paradigms on plasmid-host compatibility and an awareness of an emerging uncharted realm for ARGs.