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Original Article  |  Open Access  |  27 Dec 2023

Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019)

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One Health Implement Res 2023;3:161-76.
10.20517/ohir.2023.30 |  © The Author(s) 2023.
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Aim: This study intends to assess the occurrence of multi-drug resistant (MDR) resistant pathogens among exotic pets from France (2017-2019).

Methods: Isolates were identified using MALDI-TOF-MS. Antimicrobial susceptibility testing was conducted for 21 antimicrobials and was assayed by disk diffusion methods. Statistical analyses were carried out using GraphPad Prism® (version 9.4.1).

Results: Isolates (n = 2,100) recovered from samples of 10 small mammals (n = 1,555), 23 birds (n = 287), and 18 reptiles (n = 208) species were identified as Enterobacterales (n = 634), Pseudomonadaceae (n = 176), Pasteurellacea (n = 276), Staphylococcaceae (n = 563),Streptococcaceae (n = 259), and Enterococcaceae (n = 186). Consistent high resistance rates were observed among diverse genera and/or species to beta-lactams, tetracyclines, and macrolides. Notably, a significant prevalence of MDR bacteria was identified, with 22.8% (n = 479/2,100, P < 0.05). Furthermore, 23.5% (P < 0.05) of these MDR bacteria displayed resistance to all tested antimicrobials: E. faecalis (n = 47/49; 95.0%), E. coli (n = 19/52; 36.5%), Klebsiella spp. (n = 12/32; 37.5%), S. epidermidis(n = 7/25; 28.0%), Streptococcus spp. (n = 6/68; 8.8%), Enterococcus spp. (n = 6/23; 26.0%), Staphylococcus spp. (n = 4/51; 7.8%), Lactococcus spp. (n = 4/8; 50.0%), Citrobacter spp. (n = 3/7; 42.8%), Raoultella spp. (n = 2/3; 66.6%), Serratia spp. (n = 1/9; 11.1%), Pasteurella spp. (n = 1/14; 7.1%), and S. xylosus (n = 1/28; 3.5%).

Conclusions: This study emphasizes exotic pets as an emergent reservoir of MDR bacteria, focusing on E. faecalis as a potential route of transmission of MDR bacteria to humans, other animal species and environment. Urgent measures, including the establishment of mandatory monitoring for antimicrobial resistance (AMR) and the enforcement of restrictive antibiotic use policies in exotic pets, should be implemented to mitigate the risk of further spread and safeguard public and animal health.


Exotic pets, antimicrobial resistance, multidrug-resistance, pathogens, public health, One Health


Antimicrobial resistance (AMR) is one of the foremost global public health threats, capturing a position within the top ten concerns worldwide. AMR affects human, animal, and environmental health, making it an urgent issue that requires a comprehensive One Health approach[1]. This focuses on the risk assessment of AMR’s emergence, transmission, and maintenance at the interface between all sectors (human, animal, agriculture, and environment)[2]. Additionally, resistant bacteria are mainly determined by selective events related to environments with high selective pressure, such as the hospital and animal-production setting, due to the misuse of antimicrobials[3-6].

Furthermore, in recent years, a new paradigm is currently emerging - the adoption of a wide range of exotic species, including many with origins in the wild. This trend has facilitated unprecedented interactions and contact between wildlife, domestic animals, and humans, leading to potential ramifications[7]. Nevertheless, the AMR is poorly reported worldwide in this niche[8-10].

Noteworthy, approximately 60% of existing human pathogens and over 75% of those that have appeared during the past two decades can be traced back to animals. Among these pathogens, a considerable number have been directly linked to wildlife[11].

Furthermore, the current misunderstanding of antimicrobial use and the prevalence of AMR in exotic animals, among other pets, led the European Union (EU) to adopt Regulation (EU) 2019/6, which establishes specific provisions for veterinary medicinal prescribing. One notable provision is the introduction of electronic prescriptions, which play a crucial role in enhancing the monitoring and control of antimicrobial consumption across different animal species. These ensure that pivotal information regarding the consumption of these compounds per animal group is captured.

Previously, the monitoring of antimicrobial consumption and AMR in veterinary medicine was primarily outlined in Directive No. 2003/99/EC. However, this predominantly concentrated on food-producing animals such as livestock and aquatic animals[12]. Notably, the scarce information available on AMR in pets comes from a few studies conducted by research groups, which mainly cover dogs and cats[13,14].

In order to effectively tackle the misuse of antimicrobials, EMA updated its categorization in 2017, where Critically Important Antimicrobials (CIA) for Human Medicine are classified into two of four categories, i.e., A (Avoid), which is not authorized in veterinary medicine in the EU, and B (Restrict) applied to those which are critically important in humans, and their use in animals should be restricted and considered only when no antimicrobials of the remaining categories C or D are clinically effective. Nevertheless, these antimicrobials can be used in pets under exceptional circumstances, supported by justification[15].

Despite the inherent risks of using those categories of antimicrobials in pets, the stringent regulations surrounding their usage bring notable advantages.

It should be noted that France is among the European Union member states that have implemented an epidemiological network surveillance program to monitor AMR in animal pathogenic bacteria. This program includes data from various pets, including dogs, cats, and other species. However, the information related to the last mentioned group is not reported by specific species or category due to the limited number of antimicrobial susceptibility testing (AST) performed[16].

This study aimed to assess the prevalence of MDR pathogens between 2017 and 2019 from exotic pets originating from France and highlight if exotic pets are a reservoir of MDR bacteria and possess antimicrobial profiles that are relevant to human health.


Database source and management

The data used for this retrospective study was provided by a veterinary clinic specializing in caring for new species of pets, “Clinique des NAC”, based in Toulouse, France.

The dataset details comprise information on clinical samples (animal species, sample collection date, and origin) and microbiology outcomes (bacterial identification and antimicrobial susceptibility testing results). Duplication samples, repeated results, or data with confidential information were removed to comply with Regulation (EU) 2016/679.

Study design and samples characterization

A total of 2050 samples were collected during clinical practice between 2017 and 2019. Clinical specimens were classified according to exotic pets’ division: 23 birds (n = 287), 10 small mammals (n = 1555), and 18 reptiles (n = 208) species [Table 1]. Different clinical specimens were analyzed, such as nasal (n = 563), oral (n = 296), cutaneous (n = 287), ocular (n = 240), ear (n = 222), gastrointestinal tract (n = 163), musculoskeletal (n = 115), internal organs (n = 67), lungs (n = 59), urinary tract (n = 23), and reproductive tract (n = 15) [Supplementary Table 1].

Table 1

Distribution of clinical specimens by animal species[17]

(n = 1,555)
(n = 287)
(n = 208)
Oryctolagus cuniculus1,173Phasianidae53Testudines85
Cavia porcellus122Psittacus erithacus42Pogona vitticeps22
Mustela putorius furo75Cacatua21Python regius14
Chinchilla25Falco peregrinus17Chamaeleonidae13
Erinaceus europaeus14Columbidae16Boa constrictor11
Meriones unguiculatus9Amazona13Gekkonidae9
Octodon degus8Melopsittacus undulatus12Varanidae7
Phodopus7Nymphicus hollandicus12Elaphe6
Mustela lutreola2Parabuteo unicinctus12Python molurus5
Ecletus roratus11Gongylophis colubrinus4
Agapornis8Physignathus cocincinus4
Aquila chrysaetos5Pantherophis guttatus3
Aquila rapax4Atheris hispida2
Falco rusticolus4Crocodylia2
Hieraaetus pennatus4Morelia spilota2
Serinus canaria domestica4Epicrates cenchria1
Gyps rueppellii3
Cyanoramphus auriceps2
Falco jugger2

Bacterial identification and study of antimicrobial agents susceptibility

Etiologic agents’ identification was performed by Maldi-ToF MS at the Human Medical Biology Laboratory “BIOLAB” Avenir, Toulouse, France. Antimicrobial Susceptibility Testing (AST) was held to 21 antimicrobials [penicillins (P), amoxicillin-clavulanic acid (AMC), cefalexin (CL), ceftiofur (CTF), fusidic acid (FUS), gentamycin (GEN), tobramycin (TOB), neomycin (NC), framycetin (FCT), tylosin (TL), azithromycin (AZM), tiamulin (TIA), tetracycline (TET), doxycycline (DOX), enrofloxacin (ENR), marbofloxacin (MRB), clindamycin (CLM), lincomycin (LMC), chloramphenicol (CHL), florfenicol (FN), sulfamethoxazole-trimethoprim (SXT)] and was determined by disc diffusion method according to national standards (Comité de l’antibiogramme de la société française de microbiologie. Recommendations vétérinaires, 2018, 2019) by disk diffusion methods following European guidelines[18].

Due to the lack of representativeness of some isolates to perform AST, a cut-off was used, which excluded genera/species with less than 20 isolates. However, all isolates were considered for the analysis of the MDR profile. Additionally, the classification of isolates as susceptible, resistant, or with intermediate susceptibility was done according to EUCAST (2019) guidelines. MDR was considered when isolates were resistant to three or more antimicrobial agents of different families[19].

Statistical analysis

The prevalence of AMR across genera and/or species, along with the distribution of MDR bacterial profiles, was assessed through statistical analysis employing the Chi-square test (P  < 0.05), within GraphPad Prism® (version 9.4.1.).


Bacterial diversity

In this study, 2,100 isolates were identified as Gram-negative (n = 1,086) and Gram-positive (n = 1,014) bacteria from the collection of 2,050 samples between 2017 and 2019.

A high diversity of bacterial genera and species was found in both bacterial groups. In the Gram-negative bacteria, 15 Genera were identified: 634 isolates belonging to Enterobacterales: Escherichia coli (n = 155), Enterobacter spp. (n = 131), Klebsiella spp. (n = 111), Serratia spp. (n = 66), Proteus spp. (n = 65), Pantoea spp. (n = 30), Citrobacter spp. (n = 23), Providencia rettgeri (n = 15), Morganella spp. (n = 14), Raoultella spp. (n = 10), Salmonella spp. (n = 6), Rahnella spp. (n = 4), Yersinia pseudotuberculosis (n = 2) Erwinia pyrifolia (n = 1) and Tatumella ptyseos (n = 1); 176 isolates were identified as Pseudomonadaceae: Pseudomonas aeruginosa (n = 127) and Pseudomonas spp. (n = 49); and 276 belonged to Pasteurellaceae: Pasteurella spp. (n = 226), Haemophilus spp. (n = 26), Mannheimia spp. (n = 16), Actinobacillus spp. (n = 6), and Chelonobacter oris (n = 2) [Supplementary Table 2][17].

Regarding to Gram-positive bacteria, 563 isolates were identified within the Staphylococcaceae: Staphylococcus spp. (n = 212), S. xylosus (n = 143), S. aureus (n = 122), S. epidermidis (n = 47), Gemella spp. (n = 38) and Macrococcus caseolyticus (n = 1); 259 isolates belonged to Streptococcaceae: Streptococcus spp. (n = 249) and Lactococcus spp. (n = 10), and finally Enterococcaceae with 192 isolates: Enterococcus faecalis(n = 125),Enterococcus spp. (n = 58), and Vagonococcus fluvialis (n = 3) [Supplementary Table 3][17].

According to the sample’s origin, nasal, oral, cutaneous, and ear were the most frequent, followed by the gastrointestinal tract, musculoskeletal, lungs, and internal organs specimens [Supplementary Table 1].

The most predominant Gram-negative bacteria were Escherichia coli, followed by Enterobacter spp., Klebsiella spp., Serratia spp., and Proteus spp., whereas Gram-positive bacteria were Streptococcus spp., followed by Staphylococcus spp., S. xylosus, S. aureus, and Enterococcus faecalis[17].

Antimicrobial susceptibility testing

Gram-negative bacteria susceptibility profile

Over the triennium spanning 2017-2019, isolates exhibited high resistance levels to beta-lactams (80% to 100%: Enterobacter spp.; E. coli; P. aeruginosa; Klebsiella spp.) as well as to tetracyclines (76% to 96.3%: Klebsiella spp; E. coli; Enterobacter spp.; Serratia spp.) [Figure 1].

Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019)

Figure 1. Distribution of antimicrobial resistance among Gram-negative bacteria collected from exotic pet specimens (P < 0.05; Chi-square test).

It is noteworthy that Enterobacterales demonstrated a notable resistance percentage to tetracyclines, notably to DOX (E. coli: 94%/92%/97%; Enterobacter spp.: 91%/94%/100%; Klebsiella spp.: 89%/92%/89% and Serratia spp.: 100%/95%). In contrast, Pasteurella spp., from 2017 to 2018, showed a marked decline in the percentage of resistant isolates (43% and 13%, respectively)[17].

Regarding the susceptibility profile of E. coli, an increase in resistant isolates was observed in the 2017/18 biennium to fluoroquinolones (ENR: 26%/21%/28%; MRB: 20%/18%/26%), the same was observed for Serratia spp. (ENR: 4%/11%; MRB: 0%/4%; 2018-2019)[17].

Enterobacterales and Pseudomonadaceae showed a high distribution of isolates carrying resistance to beta-lactams (AMC - E. coli: 90%/91%/95%; Klebsiella spp.: 100%; CFT - Enterobacter spp.: 80%; P. aeruginosa: 90%/100%/100%). It is also worth noting that in 2017/18, both Proteus spp. and Klebsiella spp. had an increase in resistance to SXT (30%/41%; 33%/43%, respectively). However, it was observed a reduce in resistance to aminoglycosides and fluoroquinolones between 2017-2018: GEN - E. coli: 58%/42%/40%; Enterobacter spp.: 75%/55%/50%; Klebsiella spp.: 81%/43%/40%; Proteus spp.: 38%/7%; P. aeruginosa: 33%/28%/10%; Pasteurella spp.: 33%/15%/11%; MRB - Enterobacter spp.: 31%/20%/6%; Klebsiella spp.: 26%/34%/15%; Proteus spp.: 20%/7%; ENR - Enterobacter spp.: 47%/31%/33%; Klebsiella spp.: 55%/57%/30%; Proteus spp.: 25%/18%. Additionally, Pasteurella spp. showed a positive evolution in its susceptibility profile to most of the antibiotic families tested [Table 2][17].

Table 2

Antimicrobial resistance of Gram-negative bacteria recovered from exotic pet specimens[17]

E. coli
2017, n = 43/18818/207/1234/3610/389/347/108/41
2018, n = 72/27132/3515/1811/266/1154/5914/6711/6211/122/1215/56
2019, n = 40/17520/211/106/158/1331/3211/4010/389/34
Enterobacter spp.
2017, n = 39/18818/249/1031/3417/3612/3913/35
2018, n = 56/27117/3115/2044/4716/5110/499/38
2019, n = 36/1758/1010/2033/3311/332/349/31
Klebsiella spp.
2017, n = 34/18813/165/1225/2818/339/342/1010/30
2018, n = 49/27112/1213/308/1535/3827/4716/4718/42
2019, n = 28/1758/205/1317/198/274/273/19
Proteus spp.
2017, n = 20/1885/135/204/203/10
2018, n = 29/2711/155/282/289/22
Serratia spp.
2018, n = 25/2711/159/1023/231/240/231/21
2019, n = 29/1752/1920/213/281/280/20
Pseudomonas aeruginosa
2017, n = 38/589/107/21
2018, n = 58/7716/1614/50
2019, n = 31/4112/123/29
Pasteurella spp.
2017, n = 77/8417/381/106/185/3731/729/743/760/150/162/683/11
2018, n = 88/10918/491/110/147/482/4210/797/833/872/697/28
2019, n = 61/838/301/133/184/361/218/545/552/591/441/16

Gram-positive bacteria susceptibility profile

Over the study period from 2017 to 2019, all isolates exhibited elevated resistance rates to macrolides ranging from 50.9% to 98.9%, with a focus on E. faecalis and S. xylosus, followed by Enterococcus spp and S. aureus. Additionally, high levels of resistance were observed for beta-lactams (38.6% to 80.7%: Enterococcus faecalis, S. aureus, and S. xylosus) as well as tetracyclines (45.5% to 74.2%: S. epidermidis, S. xylosus, and E. faecalis), as depicted in Figure 2.

Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019)

Figure 2. Distribution of antimicrobial resistance among Gram-positive bacteria collected from exotic pet specimens (P < 0.05; Chi-square test).

The observed resistance levels to fluoroquinolones displayed by Enterococci are also a cause for concern(ENR - E. faecalis: 92%/98%/100%; Enterococcus spp.: 85%/80%, 2017/18). In addition, a slight enhancement in susceptibility to MRB was detected (E. faecalis: 90%/96%/85%; Enterococcus spp.: 81%/74%, 2018/19 and 2017/18, respectively).

Staphylococcaceae demonstrated an upward trend of resistance to beta-lactams and tetracyclines during 2017/18 (Staphylococcus spp. - P: 57%/43%/55%; AMC: 13%/13%/38%; CFX: 19%/8%/25%; CFT: 9%/23%; TET: 24%/26%/40%, 2017-2018; S. epidermidis - DOX: 50%/59%)[17].

Staphylococcaceae, Streptococcaceae, and Enterococcaceae showed increased resistance to macrolides at high rates (AZM - S. aureus: 59%/72%/87%; S. epidermidis: 53%/82%; S. xylosus: 81%/86%; Satphylococcus spp.: 51%/64%/71%; Streptococcus spp.: 38%/52%/63%; Enterococcus faecalis: 96%/100%/100%; Enterococcus spp.: 67%/80%, 2017/18). However, the Staphylococaceae evolved favorably in its susceptibility profile to the remaining antibiotic classes[17].

Streptococcus spp. revealed a rise in resistance profile to lincosamides (CLD: 21%/38%, 2017/18). A positive evolution in susceptibility to beta-lactams, tetracyclines, and fluoroquinolones has also been detected (MRB: 58%/48%/41%)[17].

It is noteworthy that Enterococci have exhibited a gradual decline in resistance to tetracyclines (TET - E. faecalis: 79%/60%/55%; DOX - E. faecalis: 82%/78%/71%; Enterococcus spp.: 80%/33%, 2017/18) [Table 3][17].

Table 3

Antimicrobial resistance of Gram-positive bacteria recovered from exotic pet specimens[17]

S. aureus
2017, n = 44/19311/1723/398/183/1111/3918/4210/4315/153/34
2018, n = 52/1987/2131/439/262/194/427/497/502/40
2019, n = 26/1224/1320/230/130/101/203/253/250/21
S. epidermidis
2017, n = 18/1939/178/1613/1810/184/13
2018, n = 20/19814/177/178/187/192/10
S. xylosus
2017, n = 42/19313/1526/322/217/1220/3827/3913/415/31
2018, n = 37/1988/1124/280/205/1414/324/352/345/28
Staphylococcus spp.
2017, n = 70/19313/232/163/1626/5116/357/2913/5731/6918/6912/182/507/12
2018, n = 78/19812/282/161/121/1144/697/469/3415/6218/7412/7215/545/11
2019, n = 64/12212/226/164/163/1332/456/416/1512/499/608/609/177/45
Streptococcus spp.
2017, n = 84/874/131/1127/727/1636/7654/7749/849/200/1416/683/142/12
2018, n = 96/1037/232/1646/8810/2636/8760/8740/835/1719/696/162/11
2019, n = 69/694/181/1843/684/1813/5942/6327/663/1013/47
Enterococcus faecalis
2017, n = 40/629/106/1825/2611/1428/3435/3836/4011/11
2018, n = 58/898/154/2843/439/1535/4555/5648/506/11
2019, n = 27/415/1218/186/1112/1726/2622/26
Enterococcus spp.
2017, n = 22/622/138/1212/1517/2017/21
2018, n = 28/895/1920/257/2124/3020/27

Multidrug-resistant profiles of Gram-negative and positive bacteria

It should be noted that a high percentage of isolates were MDR profile carriers: E. faecalis (63.2%, n = 79/125) followed by S. epidermidis (53.2%, n = 25/47), Enterococcus spp. (39.7%, n = 23/58), E.coli (33.5%, n = 52/155),Citrobacter spp. (30.4%, n = 7/23), Enterobacter spp. (29.7%, n = 39/131), Klebsiella spp. (28.8%, n = 32/111), Streptococcus spp. (27.3%, n = 68/249), Staphylococcus spp. (24.0%, n = 51/212), S. xylosus (19.6%, n = 28/143),S. aureus (18.9%, n = 23/122), Serratia spp. (13.6%, n = 9/66), Pasteurella spp. (6.2%, n = 14/226), and Proteus spp (4.6%, n = 3/65) [Figure 3][17].

Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019)

Figure 3. Distribution of MDR profile by genera or species (P < 0.05; Chi-square test)[17]. MDR: Multi-drug resistant.

Other isolates with low sample representativeness were also MDR carriers: Gemella spp. (7/38) Lactococcus spp. (n = 8/10), Raoultella spp., Salmonella spp. and Mannheimia spp. (n = 3/10, 3/6, and 3/16, respectively), Vagonococcus fluvialis (n = 2/3), and Rahnella spp., Actinobacillus spp., and Chelonobacter oris (n = 1/4, 1/6, and 1/2, respectively)[17].

The most prevalent co-resistance pattern observed in the MDR bacteria was the simultaneous resistance to both tetracyclines and fluoroquinolones (n = 194) [Tables 4 and 5]. Among the gram-negative bacteria, the most prominent co-resistance profile was the B-lactams-tetracyclines-fluoroquinolones combination (n = 52), followed by the aminoglycosides-tetracyclines-fluoroquinolones profile (n = 40). The first profile may also be associated with resistance to aminoglycosides [Table 4][17].

Table 4

Phenotypic features of Gram-negative bacteria carriers of heterogeneous MDR profiles[17]

Escherichia colinEnterobacter spp.nKlebsiella spp.nSalmonella spp.n
3TET-POL-FL-SUL3Actinobacillus spp.
1Pasteurella spp.
TET-ANF-PL1Citrobacter spp.BLC-TET-SUL1
1Rahnella spp.AMN-FL-SUL1
Proteus spp.AMN-TET-FL-SUL1Raoultella spp.TET-FL-PL1
Table 5

Phenotypic features of Gram-positive bacteria carriers of heterogeneous MDR profiles[17]

S. aureusnStaphylococcus spp.nGemella spp.nE. faecalisn
1BLC-MAC-TET-FL4Lactococcus spp.TET-FL-ANF3
1BLC-MAC-TET-SUL3MAC-TET-FL1Enterococcus spp.

While Gram-positive isolates demonstrate a notable co-resistance profile to macrolides-tetracyclines-fluoroquinolones (n = 102), that may also be linked to high rate resistance against macrolides [Table 5][17].

Concerned results should also be highlighted within these MDR profiles, where a high number of isolates carrying resistance to all antimicrobials tested was detected with emphasis on Enterococcus faecalis (n = 47/79), followed by E.coli (n = 19/52), Klebsiella spp. (n = 12/32), S.epidermidis (n = 7/25), Streptococcus spp (6/68), Enterococcus spp. (n = 6/23), Staphylococcus spp. (n = 4/51), Lactococcus spp. (n = 4/8), Citrobacter spp. (n = 3/7), Raoultella spp. (n = 2/3), Serratia spp (1/9), Pasteurella spp (1/14) and S. xylosus (n = 1/28) [Figure 4][17].

Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019)

Figure 4. Prevalence of MDR bacteria resistant to all antimicrobials tested (P < 0.05; Chi-square test). MDR: Multi-drug; nT: total number of MDR isolates; nR: number of isolates resistant to all antimicrobials tested; %: percentage of MDR isolates.


Gram-negative and Gram-positive bacteria-resistant carriers to critically or highly important antimicrobial agents (e.g., aminopenicillins with beta-lactamase inhibitors, Cephalosporins, fluoroquinolones, aminoglycosides, macrolides, and amphenicols), as considered by World Health Organization and recognized by European Medicines Agency, were detected in this study[15,17,20].

A parallel study on exotic pets from the Iberian Peninsula reported similar results on high rates of AMR to different antimicrobial classes. Nevertheless, data on the MDR profile was not consistent with our study concerning the distribution of bacterial genera/species that stand out most frequently (study of Muñoz-Ibarra et al., 2022: S. marcescens - 94.4% followed by C. freundii - 50%, M. morganii - 47.4%, K. pneumoniae - 46.6%, E. cloacae - 44% and E. coli - 38.3% vs. in this study E. faecalis - 63.2%, followed by S.epidermidis - 53.2%, Enterococcus spp. -39.7%, E.coli - 33.5%, Citrobacter spp. - 30.4% Enterobacter spp. - 29.7%, Klebsiella spp. - 28.8%, Streptococcus spp. - 27.3%, Staphylococcus spp. - 24.0%, S.xylosus - 19.5%, S.aureus - 18.9%, Gemella spp. - 18.4%, Serratia spp. - 13.6%, Pasteurella spp. - 6.2%, and Proteus spp 4.6%)[8,17].

Furthermore, the distribution of resistance profiles observed in this study highlighted certain disparities compared to the official results published by France. Notably, the official reports solely encompass food-producing animals, horses, cats, and dogs, while this work extends its focus to include exotic pets, which hinders the possibility of making direct comparisons with the findings of this study[16,17]. In our work, Gram-negative bacteria revealed high rates of resistance to cefalexin, disagreeing with data reported by the Agence Nationale de Sécurité Sanitaire de l’Alimentation, de l'Environnement et du Travail (83% vs. 13%)[16,17]. The same was observed for the fluoroquinolones, sulphonamides, and tetracyclines (ENR: 4%-8%; SXT: 66%; TET/DOX: 80%; food-producing animals/cats/horses). Nevertheless, some Enterobacterales, P. aeruginosa, and Pasteurella spp. approached the officially reported data, and an increase in the distribution of susceptible isolates was observed above the national average[16,17]. However, other studies from Italy and Lebanon reported higher resistance rates in E. coli (rabbits: ENR- 67%; poultry: GEN: 70%, SXT: 59%, respectively)[21,22].

It is worth noting that a positive evolution in the distribution of susceptible isolates from Enterobacterales, P. aeruginosa, and Pasteurella spp. to aminoglycosides agreed with the National Report and other studies[16,17,23].

In contrast, Enterobacter spp., currently emerging in human and veterinary medicine, showed a high rate of resistance to aminoglycosides (GEN - 50% to 75%) in our data, contrary to what has been reported by other studies and National Report (dog, cat, and equines)[16,17,24]. Isolates of Enterobacterales and Pseudomonadaceae stood out for their high resistance rate to beta-lactams (AMC - 100%), and thus do not fit with official data (cuniculture)[16,17].

Concerning Gram-positive isolates, they revealed an alarming increase in resistance rates to macrolides, fluoroquinolones, amphenicols, and tetracyclines, where E. faecalis stood out. In fact, several authors widely described this resistance profile, spanning across the animal production environment, companion animals, general environmental contexts, and healthy and hospitalized humans[3,5,25,26].

This work has provided valuable data to shed light on acknowledging AMR prevalence in exotic pets. The resistance rates documented are noticeably higher compared to those reported at the national level. However, it is worth highlighting that the National Report does not present specific data concerning the species that were investigated in this study. Furthermore, it is noteworthy to mention that the genus Enterococci, which stands out for the high occurrence of MDR isolates, is not included or reported[16].

It can be justified by the policies of each country in the strictness of the implementation of guidelines, in some cases, being almost exclusively dependent on the responsibility of the veterinarian. However, specific measures have been undertaken for the CIA through a Decree publication limiting the use of 3rd- and 4th-generation cephalosporins and fluoroquinolones, and AST is mandatory for veterinarians before using or prescribing those molecules. The goal of reducing the use of fluoroquinolones and 3rd and 4th-generations cephalosporins by 25% (between 2013 and 2016) was regulated in law and has been exceeded. Between this period, sales of 3rd- and 4th-generation cephalosporins and fluoroquinolones decreased by 94% and 84%, respectively. Tetracyclines, penicillins, sulfonamides, and macrolides are the highest-selling antimicrobials in France. Additionally, between 2010 and 2021, a marked decline in the consumption of antimicrobials used in animals in France was observed[27].

Despite global efforts to implement preventive measures, there is currently a lack of comprehensive monitoring through epidemiological surveillance regarding the transmission routes of MDR strains. Furthermore, the documented colonization events between humans and pets are not being adequately monitored or recorded[28]. Scientific literature has described that one of the most significant hazards to human health is the transfer of methicillin-resistant strains of S. aureus, vancomycin-resistant Enterococcus, or carbapenemases from pets[3,29]. Indeed, carbapenemases from companion animals have been extensively reported worldwide (19 countries from Asia, Americas, Europe, Africa, and Oceania)[29]. Nevertheless, large-scale data on the genotype MDR profile is not available. In this regard, a recent study underscores the urgent requirement to prioritize scientific research and effective communication to establish a solid evidence base for antimicrobial treatment practices in exotic species that will play a crucial key in formulating appropriate recommendations for antimicrobial use in these species[30].

Of particular concern is the simultaneous use of metal-based food additives, particularly copper compounds, in the diets of both food-producing animals and pets. This practice demands attention as it has the potential to contribute to the co-selection, persistence, and transference of AMR genes intra and inter-species, promoting its dissemination to animals, humans, and the environment[5,25].

Our findings emphasize the emergence of exotic animals as a reservoir for MDR isolates, particularly focusing on E. faecalis and E. coli. Among the identified MDR profiles, resistance to CIAs was observed.

These results suggest that exotic animals could serve as potential hotspots for bacterial diversification. To comprehensively address this global issue, large-scale studies encompassing antimicrobial susceptibility and genotyping of MDR profiles in exotic pets are essential. Additionally, veterinarians play a pivotal role in antimicrobial consumption control as key leaders in recognizing and implementing recommendations by official bodies to fight AMR. This work presents the first extensive study conducted on exotic pets from France, providing valuable insights into the status of AMR.



This manuscript references the master’s thesis of Dr. Sandro Cardoso, which was successfully defended on July 21, 2020, at the University School Vasco da Gama in Coimbra, Portugal, earning him a master’s degree in Veterinary Medicine. We extend our gratitude to Clinique des NAC, located in Toulouse, France, for providing the dataset used in this study.

Authors’ contributions

Conceptualization: Cardoso S, Silveira E

Methodology: Silveira E

Resources: Le Loc’h A

Writing-original draft preparation: Cardoso S, Silveira E

Writing-review and editing: Marques I, Almeida A, Sousa S, Saavedra MJ, Anastácio S, Silveira E

Supervision: Silveira E

All authors have read and agreed to the published version of the manuscript.

Availability of data and materials

The following supporting information can be downloaded at: Supplementary Materials.

Financial support and sponsorship


Conflicts of interest

All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate

The samples were obtained as part of veterinary clinical practice. Following Regulation (EU) 2016/679 of the European Parliament and the Council, dated April 27, 2016, which addresses the protection of natural persons regarding the processing of personal data and the free movement of such data, and repealing Directive 95/46/EC (General Data Protection Regulation), any data containing confidential information has been diligently excluded from the dataset.

Consent for publication

Not applicable.


© The Author(s) 2023.

Supplementary Materials


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Cite This Article

OAE Style

Cardoso S, Le Loc’h A, Marques I, Almeida A, Sousa S, Saavedra MJ, Anastácio S, Silveira E. Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019). One Health Implement Res 2023;3:161-76.

AMA Style

Cardoso S, Le Loc’h A, Marques I, Almeida A, Sousa S, Saavedra MJ, Anastácio S, Silveira E. Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019). One Health & Implementation Research. 2023; 3(4): 161-76.

Chicago/Turabian Style

Cardoso, Sandro, Aurélie Le Loc’h, Inês Marques, Anabela Almeida, Sérgio Sousa, Maria José Saavedra, Sofia Anastácio, Eduarda Silveira. 2023. "Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019)" One Health & Implementation Research. 3, no.4: 161-76.

ACS Style

Cardoso, S.; Le Loc’h A.; Marques I.; Almeida A.; Sousa S.; Saavedra MJ.; Anastácio S.; Silveira E. Unveiling the emergence of multidrug-resistant pathogens in exotic pets from France: a comprehensive study (2017-2019). One. Health Implement. Res. 2023, 3, 161-76.

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This article belongs to the Special Issue Antibiotic Resistance and Natural Products
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