# Detection of resistance genes and resistant bacteria in wild birds from the French Antarctic and Austral Territories

Marisa Haenni, Laetitia Du Fraysseix, Jérémy Tornos, Sabine Delannoy, Amandine Gamble, Jean-Yves Madec, Patrick Fach, Thierry Boulinier

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## To cite this version:

Marisa Haenni, Laetitia Du Fraysseix, Jérémy Tornos, Sabine Delannoy, Amandine Gamble, et al. Detection of resistance genes and resistant bacteria in wild birds from the French Antarctic and Austral Territories. 9th Symposium on Antimicrobial Resistance in Animals and the Environment (ARAE), Jul 2023, Tours (France), France. anses-04276212

HAL Id: anses-04276212

https://anses.hal.science/anses-04276212

Submitted on 8 Nov 2023

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anses

# Detection of resistance genes and resistant bacteria in wild birds from the French Antarctic and Austral Territories

Marisa HAENNI¹, Laetitia DU FRAYSSEIX¹, Jeremy TORNOS², Sabine DELANNOY³, Amandine GAMBLE⁴, Jean-Yves MADEC¹, Patrick FACH³ and Thierry BOULINIER²

¹Unité Antibiorésistance et Virulence Bactériennes, ANSES – Université de Lyon, Lyon, France

²CEFE, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France

³COLiPATH Unit & Genomics Platform IdentyPath, Laboratory for Food Safety, ANSES, Maisons-Alfort, France

⁴School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, Scotland

Contact : marisa.haenni@anses.fr

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## Introduction

Antimicrobial resistance (AMR) in wild birds most likely reflects the contamination of their natural environment with antimicrobial resistance genes (ARGs) from anthropogenic sources.

AMR acquisition in wild birds generally occurs through foraging (scavenging, predation), but the exact source of AMR in specific wild individuals is often difficult to infer.

The aim of this study was to determine the AMR load in fecal samples of wild birds living on islands of the French Antarctic and Austral Territories, which is a highly pristine environment with limited human presence.

## Material and Methods

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## Results

* No extended-spectrum beta-lactamase (ESBL) producing isolate was identified on selective plates. However, ESBL genes *bla*<sub>CTX-M-1-group</sub> and *bla*<sub>CTX-M-9-group</sub> were **sporadically identified** (n=25 and n=54) by qPCR.

* A total of 546 different bacteria were collected on non-selective plates, including 182 *Enterococcus* spp and 73 *Escherichia* spp isolates. Antibiograms revealed **very few resistance phenotypes**.

* All tested ARGs, except *mcr-1* and *tetA*, were detected at least in one sample. The most frequent ones were those conferring resistance to **aminoglycosides** (*aph(3')-Ia*, n=311; *strA* n=169; *strB*, n=190), **sulfonamides** (*sul1/sul2*, n=144/167) and **tetracyclines** (*tetB*, n=115).

* The **class 1 and class 2 integrons** were respectively found in 147 and 286 samples.

* Analysis of the qPCR data from Possession Island only (Crozet Archipelago) showed that the proportion of ARGs **decreased with distance from the scientific station** (Figure 1).

<figure><img src="image_5.png" /><figcaption>**Figure 1.** Proportion of resistance genes identified by qPCR in the king penguins (left panel) and lesser sheathbills (right panel) from Possession Island. Different sampling sites located further and further away from the scientific station were included in this analysis.</figcaption></figure>

## Discussion

ARGs have **percolated in the most pristine environments**, event though the AMR burden is still low. Indeed, direct plating of the samples without an enrichment step did not allow the isolation of ESBL-producing isolates. However, ESBL genes **could be identified using HT-qPCR**, indicating that these AMR genes are still restricted to the sub-dominant flora. Interestingly, our results showed that the proportion of ARGs **decreased with distance from the scientific station**, suggesting the role of anthropization in the spread of ARGs.

A **new sampling campaign** is currently being conducted to provide more evidence for this hypothesis.

**Acknowledgements.** We thank all people involved in the different logistical steps. **Funding.** This project was supported by the French Polar Institute (IPEV) via projet ECOPATH 1151 and by the ANSES.