A walk on the wild side: Wild ungulates as potential reservoirs of multi-drug resistant bacteria and genes, including Escherichia coli harbouring CTX-M beta-lactamases

Antimicrobial resistance among clinically significant bacteria in wildlife: An overlooked one health concern

Antimicrobial resistance (AMR) has emerged as a critical global health challenge. However, the significance of AMR is not limited to humans and domestic animals but extends to wildlife and the environment. Based on the analysis of > 200 peer-reviewed papers, this review provides comprehensive and current insights into the detection of clinically significant antimicrobial resistant bacteria and resistance genes in wild mammals, birds and reptiles worldwide. The review also examines the overlooked roles of wildlife in AMR emergence and transmission. In wildlife, AMR is potentially driven by anthropogenic activity, agricultural and environmental factors, and natural evolution. This review highlights the significance of AMR surveillance in wildlife, identifies species and geographical foci and gaps, and demonstrates the value of multifaceted One Health strategies if further escalation of AMR globally is to be curtailed.

Genomic surveillance for antimicrobial resistance - a One Health perspective

Antimicrobial resistance (AMR) - the ability of microorganisms to adapt and survive under diverse chemical selection pressures - is influenced by complex interactions between humans, companion and food-producing animals, wildlife, insects and the environment. To understand and manage the threat posed to health (human, animal, plant and environmental) and security (food and water security and biosecurity), a multifaceted 'One Health' approach to AMR surveillance is required. Genomic technologies have enabled monitoring of the mobilization, persistence and abundance of AMR genes and mutations within and between microbial populations. Their adoption has also allowed source-tracing of AMR pathogens and modelling of AMR evolution and transmission. Here, we highlight recent advances in genomic AMR surveillance and the relative strengths of different technologies for AMR surveillance and research. We showcase recent insights derived from One Health genomic surveillance and consider the challenges to broader adoption both in developed and in lower- and middle-income countries.

Implications of different waterfowl farming on cephalosporin resistance: Investigating the role of blaCTX-M-55

We investigated the cephalosporin resistance of Escherichia coli from waterfowl among different breeding mode farms. In 2021, we isolated 200 strains of E. coli from waterfowl feces samples collected from Sichuan, Heilongjiang, and Anhui provinces. The key findings are: Out of the 200 strains, 80, 80, and 40 strains were isolated from waterfowl feces samples in intensive, courtyard, and outdoor breeding mode farms, respectively. The overall positive rate of the ESBL phenotype, detecting by the double disk diffusion method, was 68.00% (136/200). In particular, the rates for intensive, courtyard, and outdoor breeding modes were 98.75%, 36.25%, and 70.00%, respectively. Results of MIC test showed drug resistance rates in the intensive breeding mode: 100.00% for cephalothin, 38.75% for cefoxitin, 100.00% for cefotaxime, and 100.00% for cefepime. In courtyard breeding mode, the corresponding rates were 100.00%, 40.00%, 63.75%, and 45.00%, respectively. In outdoor breeding mode, the corresponding rates were 100.00%, 52.50%, 82.50%, and 77.50%, respectively. The PCR results for blaCTX-M, blaTEM, blaOXA, and blaSHV showed the detection rate of blaCTX-M was highest at 75.50%, with blaCTX-M-55 is the main subtype gene, followed by blaTEM at 73.50%. We screened 58 donor strains carrying blaCTX-M-55, including 52 strains from the intensive breeding mode. These donor bacteria can transfer different plasmids to recipient E. coli J53, resulting in recipient bacteria acquiring cephalosporin resistance, and the conjugational transfer frequency ranged from 1.01 × 10-5 to 6.56 × 10-2. The transferred plasmids remained stable in recipient bacteria for up to several days without significant adaptation costs observed. During molecular typing of E. coli with conjugational transfer ability, the blaCTX-M-55 was found to be widely present in different ST strains with several phylogenetic groups. In summary, cephalosporin resistance of E. coli carried by waterfowl birds in intensive breeding mode farm was significantly higher than in courtyard and outdoor mode farms. The blaCTX-M-55 subtype gene was the prevalent ARGs and can be horizontally transferred through plasmids, which plays a key role in the spread of cephalosporin drug resistance.

Epidemiological study of antimicrobial-resistant bacteria in healthy free-ranging bantengs (Bos javanicus) and domestic cattle

Background and Aim

Antimicrobial-resistant microorganisms (ARMs) have been increasing among wild animals. Interactions occurring at the interface between wildlife, humans, and livestock can lead to the transmission of ARMs. Thus, the prevalence of ARMs in wild and domestic animals should be determined to address and prevent this issue. This study aimed to determine the resistance patterns of cefotaxime (CTX)-resistant Escherichia coli and identify the presence of extended-spectrum beta-lactamase (ESBL) genes in ESBL-producing E. coli among a population of wild banteng (Bos javanicus) and domestic cattle kept on farms located close to the Lam Pao non-hunting area, Kalasin province, Thailand.

Materials and Methods

Forty-five fecal samples were taken from wild bantengs inhabiting the Lam Pao non-hunting area in Thailand, alongside 15 samples from domestic cattle. Bacterial culture, triple sugar iron, and motile indole lysine tests were conducted to identify E. coli. A polymerase chain reaction (PCR) was conducted for specific confirmation. MacConkey agar supplemented with 2 μg/mL of CTX was used to identify CTX-resistant E. coli, which would be used to identify ESBL production based on a double-disk synergy test. Extended-spectrum beta-lactamase-producing samples were subjected to disk diffusion tests to determine resistant patterns, and the sizes of PCR bands and DNA sequencing were used to differentiate ESBL gene types.

Results

All samples tested positive for E. coli. Forty-five isolates from 15 banteng samples and three isolates from one domestic cattle sample displayed CTX-resistant and ESBL-producing traits. The banteng and domestic cattle populations exhibited nine and three distinct resistant patterns, respectively. The PCR results indicated that the banteng isolates harbored the following genes: Cefotaxime-M1 (n = 38), CTX-M9 (n = 5), and the SHV group (n = 2). All three isolates from the domestic cattle sample contained the CTX-M1 gene. Classification of ESBL genes based on the DNA sequences of the banteng isolates showed the characteristics of CTX-M15 (n = 20), CTX-M55 (n = 6), CTX-M14 (n = 5), and CTX-M79 (n = 1). The three domestic cattle isolates exhibited the characteristics of CTX-M15, CTX-M55, and CTX-M79.

Conclusion

Despite no previous antibiotic applications, approximately one-third of the banteng samples displayed CTX resistance, indicating ARM contamination within the ecosystem. The similarity in ESBL genes between the banteng and domestic cattle populations suggests potential gene transmissions between these animal groups. However, the initial source of ARMs remains unclear, as the banteng population exhibited more ESBL genes than the domestic cattle, suggesting the possibility of multiple ARM sources. These findings raise concerns because the banteng population inhabits an area that is an important source of freshwater and nourishes the entire north-east region of Thailand and other South-east Asian countries, including Laos, Cambodia, and Southern Vietnam.

Extended-Spectrum β-Lactamases (ESBL) Producing Bacteria in Animals

Animals have been identified as potential reservoirs and vectors of resistance genes, with studies showing that Gram-negative bacteria can acquire resistance through the horizontal transmission of resistance genes on plasmids. It is important to understand the distribution of antimicrobial-resistant bacteria and their drug-resistant genes in animals. Previous review articles mostly focused on a single bacterium or a single animal. Our objective is to compile all ESBL-producing bacteria isolated from various animals in recent years and provide a comprehensive viewpoint. Using a thorough PubMed literature search spanning from 1 January 2020 to 30 June 2022, studies exploring extended-spectrum beta-lactamase (ESBL) producing bacteria in animals were included. ESBL-producing bacteria are present in animals from various countries around the world. The most common sources of these bacteria were farm animals, and the most frequently isolated bacteria were Escherichia coli and Klebsiella pneumoniae. The most detected ESBL genes were blaTEM, blaSHV, and blaCTX-M. The presence of ESBL-producing bacteria in animals highlights the importance of the One Health approach to address the issue of antibiotic resistance. Further research is needed to better understand the epidemiology and mechanisms of the spread of ESBL-producing bacteria in animal populations and their potential impact on human and animal health.

Characterization of Antibiotic-Resistant Stenotrophomonas Isolates from Painted Turtles Living in the Wild

Stenotrophomonas maltophilia is a ubiquitous multidrug-resistant opportunistic pathogen commonly associated with nosocomial infections. The purpose of this study was to isolate and characterize extended-spectrum beta-lactamase (ESBL) producing bacteria from painted turtles (Chrysemys picta) living in the wild and captured in southeastern Wisconsin. Fecal samples from ten turtles were examined for ESBL producing bacteria after incubation on HardyCHROM™ ESBL agar. Two isolates were cultivated and identified by 16S rRNA gene sequencing and whole genome sequencing (WGS) as Stenotrophomonas sp. 9A and S. maltophilia 15A. They were multidrug-resistant, as determined by antibiotic susceptibility testing. Stenotrophomonas sp. 9A was found to produce an extended spectrum beta-lactamase (ESBL) and both isolates were found to be carbapenem-resistant. EDTA-modified carbapenem inactivation method (eCIM) and the modified carbapenem inactivation method (mCIM) tests were used to examine the carbapenemase production and the test results were negative. Through WGS several antimicrobial resistance genes were identified in S. maltophilia 15A. For example a chromosomal L1 β-lactamase gene, which is known to hydrolyze carbapenems, a L2 β-lactamase gene, genes for the efflux systems smeABC and smeDEF and the aminoglycosides resistance genes aac(6')-lz and aph(3')-llc were found. An L2 β-lactamase gene in Stenotrophomonas sp. 9A was identified through WGS.

A survey of antimicrobial-resistant Escherichia coli prevalence in wild mammals in Japan using antimicrobial-containing media

The emergence and spread of antimicrobial-resistant bacteria and resistance genes pose serious human and animal health concerns. Therefore, to control antimicrobial-resistant bacteria in the environment, the status of antimicrobial resistance of Escherichia coli in a variety of wild mammals and their prevalence were examined using antimicrobial-containing media. In total, 750 isolates were obtained from 274/366 (74.9%) wild mammals, and antimicrobial-resistant E. coli was detected in 37/750 isolates (4.9%) from 7 animal species (26/366 [7.1%] individuals). Using antimicrobial-containing media, 14 cefotaxime (CTX)- and 35 nalidixic acid-resistant isolates were obtained from 5 (1.4%) and 17 (4.6%) individuals, respectively. CTX-resistant isolates carried blaCTX-M-27, blaCTX-M-55, blaCTX-M-1, and blaCMY-2, with multiple resistance genes. Fluoroquinolone-resistant isolates had multiple mutations in the quinolone-resistance determining regions of gyrA and parC or qnrB19. Most resistant isolates exhibited resistance to multiple antimicrobials. The prevalence of antimicrobial-resistant bacteria observed in wild mammals was low; however, it is essential to elucidate the causative factors related to the low prevalence and transmission route of antimicrobial-resistant bacteria/resistance genes released from human activities to wild animals and prevent an increase in their frequency.

Balantioides coli Fecal Excretion in Hunted Wild Cervids (Cervus elaphus and Dama dama) from Portugal

Balantioides coli is a zoonotic enteric protozoan parasite of public veterinary health relevance and a concern in animal production and food safety. While wild cervids are recognized reservoirs for several zoonotic pathogens, little is known about the occurrence of B. coli in deer species, especially in Europe. To fill this gap, a total of 130 fecal samples from legally hunted red deer (Cervus elaphus, n = 95) and fallow deer (Dama dama, n = 35) were passively collected during two hunting seasons (October to February; 2018-2019 and 2019-2020) in Portugal. After assessment by PCR assay targeting the complete ITS1-5.8s-rRNA-ITS2 region and the 3' end of the ssu-rRNA gene of the parasite, a prevalence of 4.2% (4/95, 95% CI: 0.2-8.3) in red deer and of 5.7% (2/35, 95% CI: 0.0-13.4) in fallow deer was found. Sequence and phylogenetic analyses allowed the identification of B. coli genetic variants A (in two red deer) and B (in two red deer and two fallow deer). This is the first molecular-based description of B. coli in European deer species, whose population have increased in density and geographical range in recent years. Continued monitoring of wild ungulates as potential vectors of parasitic infection diseases of zoonotic nature is crucial to safeguard public health and food safety.