Azorean wild rabbits as reservoirs of antimicrobial resistant Escherichia coli

Rabbits as a Reservoir of Multidrug-Resistant Escherichia coli: Clonal Lineages and Public Health Impact

Escherichia coli, including extended-spectrum β-lactamases (ESBL)-producing strains, poses a global health threat due to multidrug resistance, compromising food safety and environmental integrity. In industrial settings, rabbits raised for meat have the highest consumption of antimicrobial agents compared to other food-producing animals. The European Union is facing challenges in rabbit farming as rabbit consumption declines and antibiotic-resistant strains of E. coli cause enteric diseases. The aim of this study was to investigate the antibiotic resistance profile, genetic diversity, and biofilm formation in cefotaxime-resistant E. coli strains isolated from twenty rabbit farms in Northern Portugal to address the effect of the pressing issue of antibiotic resistance in the rabbit farming industry. Resistance to critically antibiotics was observed, with high levels of resistance to several categories, such as tetracycline, ampicillin, aztreonam, and streptomycin. However, all isolates were susceptible to cefoxitin and imipenem. Multidrug resistance was common, with strains showing resistance to all antibiotics tested. The blaCTX-M variants (blaCTX-3G and blaCTX-M9), followed by the tetracycline resistance genes, were the most frequent resistance genes found. ST10 clones exhibiting significant resistance to various categories of antibiotics and harboring different resistance genes were detected. ST457 and ST2325 were important sequence types due to their association with ESBL-E. coli isolates and have been widely distributed in a variety of environments and host species. The strains evaluated showed a high capacity for biofilm formation, which varied when they were grouped by the number of classes of antibiotics to which they showed resistance (i.e., seven different classes of antibiotics, six classes of antibiotics, and three/four/five classes of antibiotics). The One Health approach integrates efforts to combat antimicrobial resistance in rabbit farming through interdisciplinary collaboration of human, animal, and environmental health. Our findings are worrisome and raise concerns. The extensive usage of antibiotics in rabbit farming emphasizes the urgent need to establish active surveillance systems.

Escherichia coli Producing Extended-Spectrum β-lactamases (ESBL) from Domestic Camels in the Canary Islands: A One Health Approach

Simple Summary

Extended-spectrum beta-lactamase (ESBL) producing Escherichia coli is an important problem in hospital settings. Camels are known to harbor multidrug-resistant Gram-negative bacteria and to be involved in the transmission of various microorganisms to humans. Fecal samples of 58 camels were recovered in the Canary Islands for detection and characterization of cefotaxime-resistant (CTX^R) and ESBL-producing E. coli isolates. Five samples carried CTX^RE. coli isolates and two of them contained ESBL-positive E. coli (3.4%) with the following characteristics: (ESBL/phylogroup/sequence type): CTX-M-15/A/ST3018 and CTX-M-15/B1/ST69. The three remaining isolates recovered from CTX-supplemented plates were ascribed to phylogroup-B₁. Due to the participation of these animals in touristic activities in the region, the potential transference of ESBL-positive bacteria between humans and animals could happen and should be further monitored.

Abstract

Objective: This work aimed to determine the carriage rate of ESBL-producing Escherichia coli as well as their genetic characteristics in camels from the Canary Islands, Spain. Methods: Fecal samples were recovered from 58 healthy camels from Gran Canaria (n = 32) and Fuerteventura Islands (n = 26) during July 2019. They were seeded on MacConkey (MC) agar no supplemented and supplemented (MC + CTX) with cefotaxime (2 µg/mL). Antimicrobial susceptibility was determined by disk diffusion test (CLSI, 2018). The presence of bla_CTX-M, bla_SHV, bla_TEM,bla_CMY-2 and bla_OXA-1/48 genes was tested by PCR/sequencing. Furthermore, the mcr-1 (colistin resistance), tetA/tetB (tetracycline resistance), int1 (integrase of class 1 integrons) and stx_1,2 genes were analyzed. Phylogenetic groups and sequence types were determined by specific-PCR/sequencing for selected isolates. Results: E. coli was obtained from all the 58 camels in MC media (100%) and in five of them in MC + CTX media (8.6%). Furthermore, 63.8% of E. coli isolates recovered from MC agar were susceptible to all the antibiotics tested. The five E. coli isolates recovered from MC + CTX media were characterized and two of them were ESBL-producers (3.4%). Both ESBL-producer isolates carried the bla_CTX-M-15 gene and belonged to the lineages ST3018 (phylogroup A) and ST69 (phylogroup B1). The 3 ESBL-negative isolates recovered from MC-CTX plates were ascribed to phylogroup-B₁. Conclusions: Camels can be a source of ESBL-producer bacteria, containing the widespread bla_CTX-M-15 gene associated with the lineages ST3018 and ST69.

Molecular characterisation of antimicrobial resistance and virulence genes in Escherichia coli strains isolated from diarrhoeic and healthy rabbits in Tunisia

The purpose of this study was to identify <em>Escherichia coli</em> isolates in diarrhoeic and healthy rabbits in Tunisia and characterise their virulence and antibiotic resistance genes. In the 2014-2015 period, 60 faecal samples from diarrhoeic and healthy rabbits were collected from different breeding farms in Tunisia. Susceptibility to 14 antimicrobial agents was tested by disc diffusion method and the mechanisms of gene resistance were evaluated using polymerase chain reaction and sequencing methods. Forty <em>E. coli</em> isolates were recovered in selective media. High frequency of resistance to tetracycline (95%) was detected, followed by different levels of resistance to sulphonamide (72.5%), streptomycin (62.5%), trimethoprim-sulfamethoxazole (60%), nalidixic acid (32.5%), ampicillin (37.5%) and ticarcillin (35%). <em>E. coli</em> strains were susceptible to cefotaxime, ceftazidime and imipenem. Different variants of bla_TEM, <em>tet</em>, <em>sul</em> genes were detected in most of the strains resistant to ampicillin, tetracycline and sulphonamide, respectively. The presence of class 1 integron was studied in 29 sulphonamide-resistant <em>E. coli</em> strains from which 15 harboured class 1 integron with four different arrangements of gene cassettes, <em>dfrA17</em>+<em>aadA5</em> (n=9), <em>dfrA1</em> + <em>aadA1</em> (n=4), <em>dfrA12</em> + <em>addA2</em> (n=1), <em>dfrA12</em>+<em>orf</em>+<em>addA2</em> (n=1). The <em>qnrB</em> gene was detected in six strains out of 13 quinolone-resistant <em>E. coli</em> strains. Seventeen <em>E. coli</em> isolates from diarrhoeic rabbits harboured the enteropathogenic eae genes associated with different virulence genes tested (<em>fimA</em>, <em>cnf1</em>, <em>aer</em>), and affiliated to B2 (n=8) and D (n=9) phylogroups. Isolated <em>E. coli</em> strains from healthy rabbit were harbouring <em>fim A</em> and/or <em>cnf1</em> genes and affiliated to A and B1 phylogroups. This study showed that <em>E. coli</em> strains from the intestinal tract of rabbits are resistant to the widely prescribed antibiotics in medicine. Therefore, they constitute a reservoir of antimicrobial-resistant genes, which may play a significant role in the spread of antimicrobial resistance. In addition, the eae virulence gene seemed to be implicated in diarrhoea in breeder rabbits in Tunisia.

Occurrence of ESBL-producing Escherichia coli in soils subjected to livestock grazing in Azores archipelago: an environment-health pollution issue?

Antibiotics are successful drugs used in human and animal therapy; however, they must be considered as environmental pollutants. This study aims to isolate and characterize the extended-spectrum β-lactamase (ESBL) producing Escherichia coli soil from Azores Archipelago subjected to livestock agricultural practices. Twenty-four soil samples were collected from three different pasture systems with different number of cattle heads, and from a control site. Antibiotic susceptibility method was performed by Kirby-Bauer disk diffusion method against 16 antibiotics, and the presence of genes encoding lactamases, antimicrobial resistance genes, virulence factors, and phylogenetic groups was determined by polymerase chain reaction (PCR). Nine ESBLs were recovered from the three grazing sites, and all isolates presented the beta-lactamase genes bla_CTX-M-3 and bla_SHV. E. coli isolates were resistance to tetracycline and streptomycin and harbored the tetB, strA, and strB genes. One isolate also showed resistance to sulfonamides, and the genes sul1 and sul2 were detected. The isolates were grouped into the following phylogenic groups: B1 (n = 6), D (n = 2), and A (n = 1). The presence of antibiotics and resistance genes in soils may be the source to the development of antimicrobial resistance, which may have negative consequences in human and animal health.

Antimicrobial susceptibility of Escherichia coli isolates obtained from wild mammals between 2013 and 2017 in Japan

The emergence and prevalence of antimicrobial-resistant bacteria in wild animals are a great concern for public health. A total of 963 Escherichia coli isolates from 475 wild mammals (242 sika deers, 112 wild boars, 113 small mammals, 4 Japanese badger, 2 Tokara cows, and 2 Amani rabbits), collected between 2013 and 2017, were examined for antimicrobial susceptibility. Resistance to at least one antimicrobial was observed in 92 of 963 isolates (9.3%). No isolates exhibited resistance to carbapenem (meropenem). Resistance to third-generation cephalosporin (cefotaxime) and fluoroquinolone (ciprofloxacin) was observed in less than 1% of the isolates. Thus, low prevalence of bacterial antimicrobial resistance was observed in wild mammals between 2013 and 2017 in Japan.

Antimicrobial resistance genes and virulence gene encoding intimin in Escherichia coli and Enterococcus isolated from wild rabbits (Oryctolagus cuniculus) in Tunisia

The spread of antimicrobial-resistant bacteria in wildlife must be viewed as a major concern with serious implications for human and animal health. Escherichia coli and enterococcal isolates were recovered from faecal samples of 49 wild rabbits (Oryctolagus cuniculus) on specific media and were characterised using biochemical and molecular tests. For all isolates, antimicrobial susceptibility testing was performed, and resistance genes were detected by PCR. Molecular typing of isolates was carried out by pulsed-field gel-electrophoresis, and E. coli strains were also tested for the presence of intimin (eae) gene characteristic of rabbit enteropathogenic E. coli. A total of 34 E. coli and 36 enterococci [E. hirae (52.8%) and E. faecalis (47.2%)] were obtained. For E. coli, resistance to tetracycline (94%), streptomycin (62%), ciprofloxacin (47%), trimethoprim-sulphamethoxazole (35%) and chloramphenicol (6%) was observed. Resistance to third-generation cephalosporins was detected in one E. coli strain that carried the bla_CMY-2 and bla_TEM-1 genes. Class 1 integrons were detected in eight isolates. For enterococci, resistance to tetracycline (63.9%), erythromycin (30.5%), streptomycin (18.2%), and chloramphenicol (5.5%) was detected. The tet(M)+tet(L), erm(B) and ant (6)-Ia genes were identified in thirteen, seven and three resistant Enterococcus strains, respectively. Molecular typing showed a high diversity among our strains. Wild rabbits could represent a reservoir of E. coli, and enterococci carrying antimicrobial resistance genes and E. coli additionally carrying the eae gene of enteropathogenic pathotypes could both contaminate the environment. our finding seems to represent the first report of eae-positive E. coli in wild rabbits.

Antimicrobial Resistance in Escherichia coli

Multidrug resistance in Escherichia coli has become a worrying issue that is increasingly observed in human but also in veterinary medicine worldwide. E. coli is intrinsically susceptible to almost all clinically relevant antimicrobial agents, but this bacterial species has a great capacity to accumulate resistance genes, mostly through horizontal gene transfer. The most problematic mechanisms in E. coli correspond to the acquisition of genes coding for extended-spectrum β-lactamases (conferring resistance to broad-spectrum cephalosporins), carbapenemases (conferring resistance to carbapenems), 16S rRNA methylases (conferring pan-resistance to aminoglycosides), plasmid-mediated quinolone resistance (PMQR) genes (conferring resistance to [fluoro]quinolones), and mcr genes (conferring resistance to polymyxins). Although the spread of carbapenemase genes has been mainly recognized in the human sector but poorly recognized in animals, colistin resistance in E. coli seems rather to be related to the use of colistin in veterinary medicine on a global scale. For the other resistance traits, their cross-transfer between the human and animal sectors still remains controversial even though genomic investigations indicate that extended-spectrum β-lactamase producers encountered in animals are distinct from those affecting humans. In addition, E. coli of animal origin often also show resistances to other-mostly older-antimicrobial agents, including tetracyclines, phenicols, sulfonamides, trimethoprim, and fosfomycin. Plasmids, especially multiresistance plasmids, but also other mobile genetic elements, such as transposons and gene cassettes in class 1 and class 2 integrons, seem to play a major role in the dissemination of resistance genes. Of note, coselection and persistence of resistances to critically important antimicrobial agents in human medicine also occurs through the massive use of antimicrobial agents in veterinary medicine, such as tetracyclines or sulfonamides, as long as all those determinants are located on the same genetic elements.

Antimicrobial Susceptibility of Escherichia coli Strains Isolated from Alouatta spp. Feces to Essential Oils

This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano), Origanum vulgaris (oregano), Thymus vulgaris (thyme), Rosmarinus officinalis (rosemary), Cymbopogon nardus (citronella), Cymbopogon citratus (lemongrass), and Eucalyptus citriodora (eucalyptus) against Escherichia coli (n = 22) strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL⁻¹; MBC mean = 2618 μg mL⁻¹), thyme (MIC mean = 2618 μg mL⁻¹; MBC mean = 2909 μg mL⁻¹), and oregano (MIC mean = 3418 μg mL⁻¹; MBC mean = 4800 μg mL⁻¹) showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL⁻¹. Our results confirm the antimicrobial potential of some essential oils, which deserve further research.