High Heterogeneity of Escherichia coli Sequence Types Harbouring ESBL/AmpC Genes on IncI1 Plasmids in the Colombian Poultry Chain

Extended-spectrum beta-lactamase-producing Klebsiella pneumoniae and risk factors associated with high total bacterial count in bulk tank milk from dairy farms in Colombia

The objective of the study was to evaluate the frequency and genetic characteristics of ESBL-producing Escherichia coli and Klebsiella spp. and the risk factors associated with a high total bacterial count in bulk tank milk samples of dairy farms in three municipalities of the Antioquia Department, Colombia. Fifteen samples were positive for E. coli and Klebsiella spp. Subsequent analysis of the 16 S rRNA gene sequences confirmed these isolates included E. coli (n = 3), K. oxytoca (n = 11), and K. pneumoniae (n = 1). None of the isolates was positive for ESBL identification by phenotypic methods, but the only the isolate of K. pneumoniae was positive for the blaSHV61 gene by sequence analysis. The antibiotic susceptibility evaluation for all Klebsiella spp. isolates identified resistance to fosfomycin (50%; 6/12) and ampicillin (100%; 12/12). While most of the herds maintain adequate hygienic quality, specific risk factors such as having more than 60 milking cows, frequent changes in milkers, milking in paddocks, and using a chlorinated product for pre-dipping have been identified as associated with a high total bacterial count > 100,000 CFU/mL in bulk tank milk. However, certain variables including the milker being the owner of the animals and the proper washing and disinfection of the milking machine contribute to maintain a high level of hygiene and quality in the raw milk stored in the tanks. In conclusion, the frequency of ESBL producers was relatively low, with only K. pneumoniae testing positive for the blaSHV ESBL type. The presence of these bacteria in milk tanks represents a potential risk to public health for consumers of raw milk and its derivatives.

Dietary supplementation of water extract of Eucommia ulmoides bark improved caecal microbiota and parameters of health in white-feathered broilers

Eucommia ulmoides has been used as a food and medicine homologue for a long time in China. We hypothesize that Eucommia ulmoides achieves its health-promoting effects via altering gut microbiota. Here, we investigated the effects of water extract of Eucommia ulmoides bark on caecal microbiota and growth performance, antioxidant activity, and immunity in white-feathered broilers treated for 42 days. A total of 108 one-day-old Cobb white-feathered broilers were randomly assigned to three treatment groups: control diet, 0.75% Eucommia ulmoides diet (EU Ⅰ) and 1.5% Eucommia ulmoides diet (EU Ⅱ). The results showed that EU Ⅱ treatment improved average body weight (ABW), thigh muscle quality and total length of intestines, and decreased the serum total triglycerides and total cholesterol (TC) (p < 0.05). Eucommia ulmoides supplementation increased serum superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant activities and content of immunoglobulins, and reduced levels of malondialdehyde and tumour necrosis factor-α (TNF-α) (p < 0.05). Moreover, the supplementation increased the diversity of caecal microbiota and reduced the pathogenic genera Escherichia Shigella and Helicobacter. The genera Ochrobactrum, Odoribater, Klebsiella, Enterobacter, Georgenia and Bifidobacterium were positively associated with the ABW, total intestinal length, serum levels of GSH-Px, SOD and immunoglobulins (p < 0.001) and negatively associated with the TC and TNF-α (p < 0.01), suggesting an association of the changes of gut microbiota and improvement of broiler health. Meanwhile, Eucommia ulmoides supplementation enriched the Kyoto Encyclopedia of Genes and Genomes pathway of exocrine secretion from the pancreas, circadian entrainment and inhibited lipopolysaccharide biosynthesis. In conclusion, Eucommia ulmoides water extract can be used as a feed additive to improve poultry industry production.

Detecting Class 1 Integrons and Their Variable Regions in Escherichia coli Whole-Genome Sequences Reported from Andean Community Countries

Various genetic elements, including integrons, are known to contribute to the development of antimicrobial resistance. Class 1 integrons have been identified in E. coli isolates and are associated with multidrug resistance in countries of the Andean Community. However, detailed information on the gene cassettes located on the variable regions of integrons is lacking. Here, we investigated the presence and diversity of class 1 integrons, using an in silico approach, in 2533 whole-genome sequences obtained from EnteroBase. IntFinder v1.0 revealed that almost one-third of isolates contained these platforms. Integron-bearing isolates were associated with environmental, food, human, and animal origins reported from all countries under scrutiny. Moreover, they were identified in clones known for their pathogenicity or multidrug resistance. Integrons carried cassettes associated with aminoglycoside (aadA), trimethoprim (dfrA), cephalosporin (blaOXA; blaDHA), and fluoroquinolone (aac(6')-Ib-cr; qnrB) resistance. These platforms showed higher diversity and larger numbers than previously reported. Moreover, integrons carrying more than three cassettes in their variable regions were determined. Monitoring the prevalence and diversity of genetic elements is necessary for recognizing emergent patterns of resistance in pathogenic bacteria, especially in countries where various factors are recognized to favor the selection of resistant microorganisms.

Characteristics of antimicrobial resistance in Escherichia coli isolated from retail meat products in North Carolina

BACKGROUND

Escherichia coli is commonly used as an indicator for antimicrobial resistance (AMR) in food, animal, environment, and human surveillance systems. Our study aimed to characterize AMR in E. coli isolated from retail meat purchased from grocery stores in North Carolina, USA as part of the National Antimicrobial Resistance Monitoring System (NARMS).

MATERIALS AND METHODS

Retail chicken (breast, n = 96; giblets, n = 24), turkey (n = 96), and pork (n = 96) products were purchased monthly from different counties in North Carolina during 2022. Label claims on packages regarding antibiotic use were recorded at collection. E. coli was isolated from meat samples using culture-based methods and isolates were characterized for antimicrobial resistance using whole genome sequencing. Multi-locus sequence typing, phylogroups, and a single nucleotide polymorphism (SNP)-based maximum-likelihood phylogenic tree was generated. Data were analyzed statistically to determine differences between antibiotic use claims and meat type.

RESULTS

Of 312 retail meat samples, 138 (44.2%) were positive for E. coli, with turkey (78/138; 56.5%) demonstrating the highest prevalence. Prevalence was lower in chicken (41/138; 29.7%) and pork (19/138;13.8%). Quality sequence data was available from 84.8% (117/138) of the E. coli isolates, which included 72 (61.5%) from turkey, 27 (23.1%) from chicken breast, and 18 (15.4%) from pork. Genes associated with AMR were detected in 77.8% (91/117) of the isolates and 35.9% (42/117) were defined as multidrug resistant (MDR: being resistant to ≥3 distinct classes of antimicrobials). Commonly observed AMR genes included tetB (35%), tetA (24.8%), aph(3'')-lb (24.8%), and blaTEM-1 (20.5%), the majority of which originated from turkey isolates. Antibiotics use claims had no statistical effect on MDR E. coli isolates from the different meat types (X2 = 2.21, p = 0.33). MDR was observed in isolates from meat products with labels indicating "no claims" (n = 29; 69%), "no antibiotics ever" (n = 9; 21.4%), and "organic" (n = 4; 9.5%). Thirty-four different replicon types were observed. AMR genes were carried on plasmids in 17 E. coli isolates, of which 15 (88.2%) were from turkey and two (11.8%) from chicken. Known sequence types (STs) were described for 81 E. coli isolates, with ST117 (8.5%), ST297 (5.1%), and ST58 (3.4%) being the most prevalent across retail meat types. The most prevalent phylogroups were B1 (29.1%) and A (28.2%). Five clonal patterns were detected among isolates.

CONCLUSIONS

E. coli prevalence and the presence of AMR and MDR were highest in turkey retail meat. The lack of an association between MDR E. coli in retail meat and antibiotic use claim, including those with no indication of antimicrobial use, suggests that additional research is required to understand the origin of resistance. The presence of ST117, an emerging human pathogen, warrants further surveillance. The isolates were distinctly diverse suggesting an instability in population dynamics.

First report of the mobile colistin resistance gene, mcr-1.26, in multidrug-resistant Escherichia coli isolated from retail chicken meat

OBJECTIVES

We isolated a highly colistin-resistant Escherichia coli, strain 58, from fresh chicken wings in Lebanon. Here, we performed in-depth phenotypic and genomic analyses to identify the resistome of the isolate, focusing on the determinants that encoded colistin resistance.

METHODS

The minimum inhibitory concentration (MIC) of colistin and resistance to other antibiotics were determined using the broth microdilution method and the Kirby-Bauer disk diffusion assay, respectively. Whole-genome sequencing (WGS) and different software available at the Center of Genomic Epidemiology were used to predict the resistome, the sequence type (ST), and the presence of virulence genes and plasmid replicon types.

RESULTS

Susceptibility testing revealed that E. coli 58 exhibited multidrug resistance, including against colistin (MIC = 32 µg/mL). Whole-genome sequencing analyses showed that E. coli 58 carried 26 antimicrobial resistance genes associated with resistance to polymyxins (mcr-1.26), β-lactams (blaTEM-1b and blaCMY-2), fosfomycin (fosA4), aminoglycosides (aac(3)-IId, aadA2b, aadA5, partial aadA1, aph(3'')-Ia, aph(3')-Ia, and aph(6)-Id), tetracyclines (tetA and tetM), quinolones (qnrS1), sulphonamides (sul2 and sul3), trimethoprim (dfrA14, dfrA17, and dfrA5), phenicols (floR and cmlA1), macrolides (mphA), lincosamides (lnu(F)), quaternary ammonium compounds (partial qacL and qacE), and peroxides (sitABCD). mcr-1.26 was located on an IncX4 plasmid and induced colistin resistance in otherwise naïve E. coli and Salmonella Enteritidis. Escherichia coli 58 was predicted to be a human pathogen and belonged to ST3107.

CONCLUSION

To our knowledge, this is the first report of mcr-1.26 in poultry meat worldwide. We previously reported mcr-1.26 in an MDR E. coli (ST2207) isolated from a pigeon in Lebanon, which suggests that it might be spreading in different animal hosts and genetic backgrounds.

Genetic characterization of Escherichia coli and Klebsiella spp. from humans and poultry in Nigeria

The emergence of antibiotic resistance in livestock, especially food-producing animals, is of major public health importance as a result of the possibility of these bacteria entering the food chain. In this study, the genetic characteristics of antibiotic-resistant Escherichia coli and Klebsiella spp. isolates from humans and poultry in Edo state, Nigeria, were investigated. In April 2017, 45 Klebsiella spp. and 46 E. coli isolates were obtained from urine, clinical wounds, nasal and chicken faecal samples. Isolates were recovered and identified as previously described. Species identification was achieved by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and ribosomal multilocus sequence typing. Antimicrobial susceptibility testing was carried out using the Kirby-Bauer method for 12 antibiotics. A double disc synergy test was used to screen for extended-spectrum beta-lactamse (ESBL) production. Whole genome sequencing was performed for strain characterization of the isolates. Thirteen Klebsiella spp. isolates yielded positive results by the ESBL phenotypic test and harboured ESBL genes. Of the 46 E. coli isolates, 21 human and 13 poultry isolates were resistant to at least one of the tested antibiotics. Four human E. coli isolates harboured ESBL genes and revealed positive results when applying ESBL double disc synergy tests. ESBL genes in the Klebsiella spp. and E. coli isolates include bla CTX-M-15 and bla SHV-28. Whole genome-based core gene multilocus sequence typing of the Klebsiella spp. and E. coli isolates revealed a close relatedness among the isolates. An integrated 'One Health' surveillance system is required to monitor transmission of antimicrobial resistance in Nigeria.

Enumeration, antimicrobial resistance and genomic characterization of extended-spectrum β-lactamases producing Escherichia coli from supermarket chicken meat in the United Arab Emirates

The occurrence and counts of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in retail chicken sold in the United Arab Emirates (UAE) were investigated in this study. Results indicated that 79.68 % of chicken carcasses (251/315) sampled from UAE supermarkets harbored ESBL-producing E. coli. About half (51.75 % [163/315]) of the tested samples had an ESBL-producing E. coli count range between ≥3 log₁₀ and < 5 log₁₀ CFU/g. The antimicrobial resistance profiles of a subset of 100 isolates showed high rates of non-susceptibility to clinically significant antibiotics, particularly ciprofloxacin (80 %) and cefepime (46 %). Moreover, 7 % of the isolates exhibited resistance to colistin, with PCR-based screening revealing the presence of the mcr-1 gene in all colistin-resistant isolates. Multiplex PCR screening identified bla_CTX-M and bla_TEM genes as the most frequently presented genes among the phenotypically confirmed ESBL-producing E. coli. Further whole-genome sequencing and bioinformatic analysis of 27 ESBL-producing E. coli isolates showed that the gene family bla_CTX group 1 was the most prevalent, notably CTX-M-55 (55.55 % [15/27]), followed by CTX-M-15 (22.22 % [6/27]). The most common sequence types (STs) were ST359 and ST1011, with three evident clusters identified based on phylogenomic analysis, aligned with isolates from specific production companies. Analysis of plasmid incompatibility types revealed IncFIB, IncFII, Incl2, and IncX1 as the most commonly featured plasmids. The findings of this study indicate a noticeable prevalence and high counts of ESBL-producing E. coli in chicken sampled from supermarkets in the UAE. The high rates of antimicrobial resistance to clinically important antibiotics highlight the potential public health risk associated with consuming chicken contaminated with ESBL-producing E. coli. Overall, this study emphasizes the importance of continued antimicrobial resistance monitoring in the UAE food chain and calls for further exposure risk assessment of the consumption of ESBL-producing E. coli via chicken meat.

Evaluating Antimicrobial Resistance Trends in Commensal Escherichia coli Isolated from Cecal Samples of Swine at Slaughter in the United States, 2013-2019

The emergence of antimicrobial resistance (AMR) in commensal and pathogenic enteric bacteria of swine is a public health threat. This study evaluated publicly available AMR surveillance data collected by the National Antimicrobial Resistance Monitoring System (NARMS) by assessing AMR patterns and temporal trends in commensal E. coli isolated from cecal samples of swine at slaughter across the United States. We applied the Mann-Kendall test (MKT) and a linear regression trend line to detect significant trends in the proportion of resistant isolates to individual antimicrobials over the study period. A Poisson regression model assessed differences among years in the number of antimicrobials to which an E. coli isolate was resistant. Among the 3237 E. coli isolates, a very high prevalence of resistance for tetracycline (67.62%), and high resistance for streptomycin (24.13%), and ampicillin (21.10%) were identified. The MKT and the linear trend line showed a significantly increasing temporal trend for amoxicillin-clavulanic acid, ampicillin, azithromycin, cefoxitin, ceftriaxone, and trimethoprim-sulfamethoxazole. Compared to 2013 the number of antimicrobials to which an E. coli isolate was resistant was significantly higher in the years 2017, 2018, and 2019. The increasing temporal trend of resistance to important antimicrobials for human medicine (e.g., third-generation cephalosporins) and the increase in multidrug resistance in the later years of the study are concerning and should be followed up by studies to identify sources and risk factors for the selection of AMR.

Characterization of ESBL-producing Escherichia spp. and report of an mcr-1 colistin-resistance Escherichia fergusonni strain from minced meat in Pamplona, Colombia

Foods of animal origin are increasingly considered a source of extended spectrum β-lactamase (ESBL) producing bacteria which can disseminate throughout the food chain and become a health concern for humans. This work aimed to evaluate the occurrence of ESBL-producing Escherichia coli in 100 retail minced meat samples taken in markets in Pamplona, Colombia. A total of 19 ESBL-producing isolates were obtained, 18 identified as E. coli and one as E. fergusonii. Fifteen isolates (78.9 %) carried bla_CTX-M and bla_TEM genes, one (5.2 %) bla_SHV and bla_TEM genes, one isolate (5.2 %) carried bla_CTX-M and one (5.2 %) bla_SHV alone. The majority of CTX-M-positive E. coli isolates carried the bla_CTX-M-15 gene (13 isolates), being the bla_CTX-M-9, bla_CTX-M-2, and bla_CTX-M-8 (one isolate each) also detected. Two SHV-positive isolates presented the bla_SHV-5 and bla_SHV-12 allele. The isolate identified as E. fergusonii was positive for bla_CTX-M-65 gene and mcr-1 gene. Sixteen isolates (84.2 %) belonged to phylogroups A and B1 and grouped together in the phylogenetic tree obtained by MLST; phylogroups E and F were also detected. Transfer of ESBL resistance was demonstrated for the E. fergusonii isolate. Whole genome sequencing of this isolate revealed the presence of plasmids carrying additional resistance genes. This investigation showed the high prevalence of ESBL-producing E. coli in retail samples of minced meat. Also, the isolation of a strain of E. fergusonii is an additional concern, as some resistance genes are located in mobile elements, which can be transmitted to other bacteria. These evidences support the increasing public health concern considering the spreading of resistance genes through the food chain.

Exploring broilers and native fowls of Andaman and Nicobar Islands as a source of β-lactamase-producing Enterobacteriaceae even with limited anthropogenic activities and docking-based identification of catalytic domains in novel β-lactamase variants

Objectives

The present study was conducted to detect the occurrence of β-lactamase and biofilm-producing Escherichia coli, Salmonella, and Klebsiella in broilers and native fowl reared in the Andaman and Nicobar Islands, India. The study also included molecular docking experiments to confirm the nature of the catalytic domains found in the β-lactamase variants obtained and to reveal the clonal relationship of the isolates with human clinical strains from the database.

Materials and methods

A total of 199 cloacal swabs were collected from five poultry breeds/varieties (broiler, Vanraja, Desi, Nicobari, and layer) in three districts of the Andaman and Nicobar Islands. E. coli, Salmonella enterica, and Klebsiella pneumoniae were isolated by standard techniques and confirmed by PCR. Phenotypical β-lactamase producers were identified by a double-disc test. The genes (bla _CTX, bla _SHV, bla _TEM , and bla _AmpC) were screened, and selected sequences of β-lactamase variants were submitted to DDBJ. Homology modeling, model validation, and active site identification of different β-lactamase variants were done by the SWISS-MODEL. Molecular docking was performed to identify the catalytic domains of the β-lactamase variants. The selected β-lactamase sequences were compared with the Indian ESBL sequences from human clinical strains in NCBI-GenBank.

Results

In total, 425 Enterobacteriaceae strains were isolated from the collected samples. Klebsiella pneumoniae (42.58%) was found to be the most prevalent, followed by Salmonella enterica (30.82%) and E. coli (26.58%). The phenotypical antibiogram of all 425 isolates showed the highest resistance against oxytetracycline (61-76%) and the lowest against gentamicin (15-20%). Phenotypical production of β-lactamase enzymes was observed in 141 (33.38%) isolates. The isolation rate of β-lactamase producing E. coli, Salmonella enterica, and Klebsiella pneumoniae was significantly higher (p < 0.05) in the birds reared in the South Andaman district (25.6, 17.5, and 18.7%, respectively) than in Nicobar (11.5, 7.6, 7.1%, respectively). Genotyping of the β-lactamase-producing isolates revealed the maximum possession of bla _TEM, followed by bla _SHV and bla _{CTX - M}. The nucleotide sequences were found to be similar with bla _{CTX - M-15}, bla _{SHV - 11}, bla _{SHV - 27}, bla _{SHV - 228}, bla _{TEM - 1}, and bla _AmpC in BLAST search. Distribution of studied biofilm-associated genes in Enterobacteriaceae strains from different varieties of the birds revealed that the layer birds had the maximum possession, followed by Vanraja, Desi, broilers, and Nicobari fowls. The phylogenetic analysis of selected sequences revealed a partial clonal relationship with human clinical strains of the Indian subcontinent. Molecular docking depicted the Gibbs free energy release for 10 different macromolecules (proteins) and ligand (antibiotic) complexes, ranging from -8.1 (SHV-27 + cefotaxime) to -7 (TEM-1 + cefotaxime) kcal/mol.

Conclusion and relevance

The study revealed β-lactamase variants circulating in the fowl population of the Andaman and Nicobar Islands (India), even in remote places with low anthropogenic activity. Most of the strains possessed bla _{TEM - 1}, followed by bla _{CTX - M-15}. Possession of bla _{SHV - 11}, bla _{SHV - 27}, and bla _{SHV - 228} in poultry Enterobacteriaceae strains was not reported earlier from any part of the world. The phylogenetic analysis revealed a partial clonal relationship of β-lactamase sequences with the human clinical strains isolated from the Indian subcontinent.

Isolation of Escherichia coli and Klebsiella pneumoniae strains producing extended spectrum β-lactamases from dog urine of the Metropolitan Area of the Aburrá Valley Antioquia-Colombia

Escherichia coli and Klebsiella pneumoniae are the most common pathogens causing urinary tract infections in humans and animals. Close contact between humans and companion animals can facilitate the spread of multidrugresistant pathogens between both species. Objective: To characterize extended-spectrum β-lactamases (ESBL) -producing E. coli and K. pneumoniae isolated from dogs with urinary tract infections in the metropolitan area of Valle del Aburrá (Antioquia, Colombia). Methods: Three-hundred seventy-one urine samples collected from March 2018 to March 2019 in a veterinary clinical laboratory were analyzed. E. coli and K. pneumoniae isolates were detected in chromogenic agar and identified by biochemical tests. Susceptibility testing was performed by disc diffusion and ESBL production was evaluated by the double disk test in all isolates. MIC determination of ESBL-positive isolates were performed on the automated VITEK®2 system. Multiple PCR was used for the detection of CTX-M beta-lactamases (group 1, 2, 9 and 8/25), SHV, TEM and AmpC of plasmid origin in ESBL-positive isolates. Results: In total 22 out 371 isolates were positive for ESBL production by double disc test, 11 E. coli (ESBL-Ec) and 11 K. pneumoniae (ESBL-Kp). The multiple PCR detected CTX-M group 1 in the 22 ESBL-positive isolates. Multi-drug resistance was observed in all ESBL-producing isolates Conclusions:  A high frequency of antibiotic multi-resistance was found in ESBL-Ec and ESBL-Kp. The main ESBL detected was CTX-M group 1, which also prevails in human isolates.

Establishing a marine monitoring programme to assess antibiotic resistance: A case study from the Gulf Cooperation Council (GCC) region

The World Health Organization considers antimicrobial resistance as one of the most pressing global issues which poses a fundamental threat to human health, development, and security. Due to demographic and environmental factors, the marine environment of the Gulf Cooperation Council (GCC) region may be particularly susceptible to the threat of antimicrobial resistance. However, there is currently little information on the presence of AMR in the GCC marine environment to inform the design of appropriate targeted surveillance activities. The objective of this study was to develop, implement and conduct a rapid regional baseline monitoring survey of the presence of AMR in the GCC marine environment, through the analysis of seawater collected from high-risk areas across four GCC states: (Bahrain, Oman, Kuwait, and the United Arab Emirates). 560 Escherichia coli strains were analysed as part of this monitoring programme between December 2018 and May 2019. Multi-drug resistance (resistance to three or more structural classes of antimicrobials) was observed in 32.5% of tested isolates. High levels of reduced susceptibility to ampicillin (29.6%), nalidixic acid (27.9%), tetracycline (27.5%), sulfamethoxazole (22.5%) and trimethoprim (22.5%) were observed. Reduced susceptibility to the high priority critically important antimicrobials: azithromycin (9.3%), ceftazidime (12.7%), cefotaxime (12.7%), ciprofloxacin (44.6%), gentamicin (2.7%) and tigecycline (0.5%), was also noted. A subset of 173 isolates was whole genome sequenced, and high carriage rates of qnrS1 (60/173) and bla _CTX-M-15 (45/173) were observed, correlating with reduced susceptibility to the fluoroquinolones and third generation cephalosporins, respectively. This study is important because of the resistance patterns observed, the demonstrated utility in applying genomic-based approaches to routine microbiological monitoring, and the overall establishment of a transnational AMR surveillance framework focussed on coastal and marine environments.

Evaluación de la administración de medicamentos veterinarios en hatos lecheros de quince municipios de Cundinamarca, Colombia

Objetivo Evaluar el conocimiento en el uso de Medicamentos de Uso Veterinario (MUV) de los productores ganaderos y personal involucrado en Bogotá y municipios aledaños. Métodos Se realizó un estudio de corte transversal a través de entrevistas a operarios y productores ganaderos de una muestra de 30 hatos lecheros localizados en 15 municipios cerca de Bogotá, Cundinamarca. Resultados Se identificó la implementación de prácticas para la administración de MUV, incluyendo parámetros que influencian su administración y conocimientos en las personas que los prescriben y administran. Se encontró que los medicamentos de mayor frecuencia fueron los antimicrobianos con 60,7%, entre los cuales se destaca el uso de penicilina y oxitetraciclina. Los MUV inyectables (parenterales) fueron las formas más frecuentes de aplicación con un 64,7%. Se identificaron 251 MUV en los hatos lecheros, de los cuales el 81,3% están compuestos por principios activos que requieren tiempo de retiro en leche y carne. Se destaca el rol del mayordomo en el cuidado animal a nivel diagnóstico y administración del tratamiento. Conclusión El presente estudio sugiere que el uso de MUV es implementado empíricamente en producciones lecheras y podría contribuir a mediano y largo plazo a la emergencia de cepas con resistencia a MUV.

Comparative Characteristics and Pathogenic Potential of Escherichia coli Isolates Originating from Poultry Farms, Retail Meat, and Human Urinary Tract Infection

The pathogenicity of many bacterial strains is determined by the acquisition of virulence genes and depends on many factors. The aim of this study was to analyse the phylogenetic background, virulence patterns, and drug susceptibility of 132 E. coli isolates tested in the context of the ExPEC (Extraintestinal Pathogenic E. coli) pathotype and the correlation of these features with bacterial isolation source: food (retail meat), poultry farms (AFEC—Avian Faecal E. coli), and patients with UTI (urinary tract infection) symptoms. The drug-susceptibility results of tested E. coli isolates obtained indicate that the resistance profile—ampicillin/tetracycline/trimethoprim+sulfamethoxazole/ciprofloxacin (AMP/TE/SXT/CIP)—was most frequently observed. The multidrug resistance (MDR) phenotype was found in 31.8% of isolates from poultry farms, 36.8% of strains isolated from food, and 20% of clinical samples. The greatest similarity of virulence profiles applied to isolates derived from poultry farms and food. Most of the AFEC from poultry farms and food-derived isolates belonged to commensals from phylogroups A and B1, while among the isolates from patients with UTI symptoms, the most common was the B2 phylogroup. The collective analysis showed similarity of the three studied groups of E. coli isolates in terms of the presented patterns of antimicrobial resistance, while the virulence profiles of the isolates studied showed great diversity. The phylogroup analysis showed no similarity between the poultry/food isolates and the UTI isolates, which had significant pathogenic potential.

A rich mosaic of resistance in extended-spectrum β-lactamase-producing Escherichia coli isolated from red foxes (Vulpes vulpes) in Poland as a potential effect of increasing synanthropization

In our research, we analyzed the resistance of cephalosporin-resistant E. coli strains to antimicrobial agents. The strains were collected during five years from wild animal species commonly inhabiting Poland. We have identified the type of β-lactamases produced and the multidrug-resistance profile. Most strains (73.8%) had genes encoding ESBL enzymes, mainly CTX-M-1 and TEM. Almost all AmpC-β-lactamase-producing isolates had the bla_CMY-2 gene. Almost 70% of the strains tested showed a multi-drug resistance profile. The dominant phenotype was resistance to tetracycline (69.05%), and/or sulfamethoxazole (57.1%). We also found high resistance to quinolones: ciprofloxacin 35.7% and nalidixic acid 52.4%. The phenotypic resistance of the strains was in most cases confirmed by the presence of corresponding genes. Among strains, 26.2% were carriers of plasmid-mediated quinolone resistance genes (PMQR). MLST analysis revealed a large clonal variation of the strains, which was reflected in 28 different sequence types. More than half of the strains (54.7%) were classified into the following sequence complexes: 10, 23, 69, 101, 155, 156, 168, 354, 398, 446, and 648. Only one strain in the studied group was assigned to the ExPEC pathotype and represented sequence type 117. The results of our research have confirmed that isolates obtained from wild animals possess many resistance determinants and sequence types, which are also found in food-producing animals and humans. This reflects the doctrine of "One health", which clearly indicates that human health is inextricably linked with animal health as well as degree of environmental contamination. We conclude that the resistance and virulence profiles of strains isolated from wildlife animals may be a resultant of various sources encountered by animals, creating a rich and varied mosaic of genes, which is very often unpredictable and not reflected in the correlation between the sequence type and the gene profile of resistance or virulence observed in epidemic clones.

Pan-Resistome Characterization of Uropathogenic Escherichia coli and Klebsiella pneumoniae Strains Circulating in Uganda and Kenya, Isolated from 2017-2018

Urinary tract infection (UTI) develops after a pathogen adheres to the inner lining of the urinary tract. Cases of UTIs are predominantly caused by several Gram-negative bacteria and account for high morbidity in the clinical and community settings. Of greater concern are the strains carrying antimicrobial resistance (AMR)-conferring genes. The gravity of a UTI is also determined by a spectrum of other virulence factors. This study represents a pilot project to investigate the burden of AMR among uropathogens in East Africa. We examined bacterial samples isolated in 2017–2018 from in- and out-patients in Kenya (KY) and Uganda (UG) that presented with clinical symptoms of UTI. We reconstructed the evolutionary history of the strains, investigated their population structure, and performed comparative analysis their pangenome contents. We found 55 Escherichia coli and 19 Klebsiella pneumoniae strains confirmed uropathogenic following screening for the prevalence of UTI virulence genes including fimH, iutA, feoA/B/C, mrkD, and foc. We identified 18 different sequence types in E. coli population while all K. pneumoniae strains belong to ST11. The most prevalent E. coli sequence types were ST131 (26%), ST335/1193 (10%), and ST10 (6%). Diverse plasmid types were observed in both collections such as Incompatibility (IncF/IncH/IncQ1/IncX4) and Col groups. Pangenome analysis of each set revealed a total of 2862 and 3464 genes comprised the core genome of E. coli and K. pneumoniae population, respectively. Among these are acquired AMR determinants including fluoroquinolone resistance-conferring genes aac(3)-Ib-cr and other significant genes: aad, tet, sul1, sul2, and cat, which are associated with aminoglycoside, tetracycline, sulfonamide, and chloramphenicol resistance, respectively. Accessory genomes of both species collections were detected several β-lactamase genes, bla_CTX-M, bla_TEM and bla_OXA, or bla_NDM. Overall, 93% are multi-drug resistant in the E. coli collection while 100% of the K. pneumoniae strains contained genes that are associated with resistance to three or more antibiotic classes. Our findings illustrate the abundant acquired resistome and virulome repertoire in uropathogenic E. coli and K. pneumoniae, which are mainly disseminated via clonal and horizontal transfer, circulating in the East African region. We further demonstrate here that routine genomic surveillance is necessary for high-resolution bacterial epidemiology of these important AMR pathogens.

Colistin-resistant mcr-1-positive Escherichia coli ST1775-H137 co-harboring blaCTX-M-2 and blaCMY-2 recovered from an urban stream

The rapid dissemination of colistin resistance mcr-type genes and extended-spectrum β-lactamase-encoding genes at the human-animal-environment interface has raised concerns worldwide. In this study, we performed a genomic investigation of a multidrug (MDR)- and colistin-resistant Escherichia coli strain recovered from an urban stream strongly affected by pollution and used for recreational purposes in Brazil. E. coli strain EW827 was resistant to clinically significant antimicrobials, including polymyxins, extended-spectrum cephalosporins, and fluoroquinolones. Whole-genome sequencing analysis revealed that EW827 strain belonged to ST1775 and carried the fimH137 allele, clinically relevant antimicrobial resistance genes (e.g., mcr-1.1, bla_CTX-M-2, and bla_CMY-2), tolerance genes to metals, and biocide resistance genes. Moreover, IncX4 and IncI1-ST12 replicon types were identified carrying mcr-1.1 and bla_CMY-2, respectively. A novel genetic environment of the mcr-1.1 gene, in which a 258-bp ∆IS5-like was inserted in the opposite orientation upstream of the mcr-1.1-pap2 element, was also detected. Additionally, the bla_CTX-M-2 gene was harbored by a Tn21-like element on the chromosome. The occurrence of MDR E. coli co-harboring mcr-1.1, bla_CTX-M-2, and bla_CMY-2 in urban water represents a potential risk to humans, animals, and environmental safety. Therefore, epidemiological studies are required to monitoring multidrug-resistant bacteria and their antimicrobial resistance genes in aquatic ecosystems to determine possible routes and fates of these genes.

Screening of Epidemiologically Significant Mechanisms of Antibiotics to β-Lactams in Enterobacteriaceae - Pathogens of Zoonoses

Among the acquired mechanisms of resistance to antibiotics of microorganisms, the production of beta-lactamases, enzymes that inactivate penicillins, cephalosporins, carbapenems, and monobactams, is widespread. Most often, such beta-lactamases, in particular ESBL (extended-spectrum beta-lactamases), are capable of destroying III and IV generations of cephalosporins. One of the important ESBL producers is Escherichia coli and, to a lesser extent, Salmonella enteritidis, which are clinically significant in animals and humans. The purpose of the study was to screen ESBL DDM using cephalosporin markers and screening of mobile extrachromosomal factors of bacterial heredity – plasmids (potentially dangerous factors of genetic transport) in isolates of E. coli and S. enteritidis, polyresistant to aminoderms, from environmental objects, patho- and biological material, raw materials and products of animal origin. Results of our studies have shown the level of their distribution among animals, poultry, since from 13 field isolates of E. coli isolated from the milk of cows with mastitis and pathological material from pigs, ESBL production was found in 3 strains (23.1%) and from 18 field isolates of S. enteritidis isolated from pathological material from poultry, ESBL production was found in 2 strains (11.1%). Based on the results of molecular genetics studies, the presence of resistance plasmids (R-plasmids) in 9 field E. coli isolates was confirmed, 4 of which produced acquired beta-lactamases, incl. ESBL and 8 field isolates of S. enteritidis, 7 of which confirmed the presence of acquired carbapenemases.

Molecular epidemiology of cefotaxime-resistant but ceftazidime-susceptible Enterobacterales and evaluation of the in vitro bactericidal activity of ceftazidime and cefepime

Extended-spectrum β-lactamases' (ESBLs) production is the main resistance mechanism to third-generation cephalosporins (TGCs) in gram-negative bacilli. In Argentina, there is a high prevalence of cefotaximase-type ESBLs (CTX-M). For this reason, dissociated resistance phenotype (DRP) displaying a profile of resistance to cefotaxime (CTX) and susceptibility to ceftazidime (CAZ) might be detected. The aims of this study were to determine the prevalence of DRP in Enterobacterales clinical isolates, to characterize the mechanisms responsible for this phenotype and to evaluate the in vitro behaviour against different antibiotics. Sixty Enterobacterales resistant to any TGC were studied, and among them, 25% displayed a DRP. The β-lactamases associated with DRP were 5/11 CTX-M-2, 4/11 CTX-M-14, 1/11 CTX-M-15 and 1/11 CMY-2 in E. coli, 2/3 CTX-M-2 and 1/3 CMY-2 in P. mirabilis and 1/1 CTX-M-14 in K. pneumoniae. Furthermore, CTX-M-2 and CTX-M-14 were related with DRP in both wild-type isolates and the corresponding transconjugants. Time-kill experiments showed CAZ bactericidal activity on CTX-M-2-and CTX-M-14-producing strains and bacterial regrowth in those CMY-2 producers. An opposite behaviour was evident when cefepime (FEP) was used. However, CAZ and gentamicin combination showed a synergistic effect against the CMY-2 producers. We concluded that Enterobacterales with DRP responded differently to CAZ or FEP depending on the type of β-lactamase they possess, suggesting that these cephalosporins could be a therapeutic option. Therefore, the characterization of the involved resistance mechanism might contribute to define the appropriate antibiotic treatment.

Phenotypic and genotypic characterization of mcr-1-positive multidrug-resistant Escherichia coli ST93, ST117, ST156, ST10, and ST744 isolated from poultry in Poland

Background

A plasmid-mediated mechanism of bacterial resistance to polymyxin is a serious threat to public health worldwide. The present study aimed to determine the occurrence of plasmid-mediated colistin resistance genes and to conduct the molecular characterization of mcr-positive Escherichia coli strains isolated from Polish poultry.

Methods

In this study, 318 E. coli strains were characterized by the prevalence of mcr1–mcr5 genes, antimicrobial susceptibility testing by minimal inhibitory concentration method, the presence of antimicrobial resistance genes was screened by PCR, and the biofilm formation ability was tested using the crystal violet staining method. Genetic relatedness of mcr-1-positive E. coli strains was evaluated by multilocus sequence typing method.

Results

Among the 318 E. coli isolates, 17 (5.35%) harbored the mcr-1 gene. High antimicrobial resistance rates were observed for ampicillin (100%), tetracycline (88.24%), and chloramphenicol (82.35%). All mcr-1-positive E. coli strains were multidrug-resistant, and as many as 88.24% of the isolates contained the bla_TEM gene, tetracycline (tetA and tetB), and sulfonamide (sul1, sul2, and sul3) resistance genes. Additionally, 41.18% of multidrug-resistant, mcr-1-positive E. coli isolates were moderate biofilm producers, while the rest of the strains showed weak biofilm production. Nine different sequence types were identified, and the dominant ST was ST93 (29.41%), followed by ST117 (17.65%), ST156 (11.76%), ST 8979 (11.76%), ST744 (5.88%), and ST10 (5.88%). Moreover, the new ST was identified in this study.

Conclusions

Our results showed a low occurrence of mcr-1-positive E. coli strains isolated from Polish poultry; however, all the isolated strains were resistant to multiple antimicrobial agents and were able to form biofilms at low or medium level.

Incompatibility Group I1 (IncI1) Plasmids: Their Genetics, Biology, and Public Health Relevance

Bacterial plasmids are extrachromosomal genetic elements that often carry antimicrobial resistance (AMR) genes and genes encoding increased virulence and can be transmissible among bacteria by conjugation. One key group of plasmids is the incompatibility group I1 (IncI1) plasmids, which have been isolated from multiple Enterobacteriaceae of food animal origin and clinically ill human patients. The IncI group of plasmids were initially characterized due to their sensitivity to the filamentous bacteriophage If1. Two prototypical IncI1 plasmids, R64 and pColIb-P9, have been extensively studied, and the plasmids consist of unique regions associated with plasmid replication, plasmid stability/maintenance, transfer machinery apparatus, single-stranded DNA transfer, and antimicrobial resistance. IncI1 plasmids are somewhat unique in that they encode two types of sex pili, a thick, rigid pilus necessary for mating and a thin, flexible pilus that helps stabilize bacteria for plasmid transfer in liquid environments. A key public health concern with IncI1 plasmids is their ability to carry antimicrobial resistance genes, including those associated with critically important antimicrobials used to treat severe cases of enteric infections, including the third-generation cephalosporins. Because of the potential importance of these plasmids, this review focuses on the distribution of the plasmids, their phenotypic characteristics associated with antimicrobial resistance and virulence, and their replication, maintenance, and transfer.

Probiotics and potential applications for alternative poultry production systems

Concerns over animal welfare continue to be a critical component of law and policies associated with commercial food animal production. Social and market pressures are the driving forces behind the legislation and result in the change of poultry production management systems. As a result, the movement toward cage-free and aviary-based egg production systems has become standard practices. Cage-based systems being replaced by alternative methods that offer a suitable housing environment to meet or exceed poultry welfare needs and require different management, including the ban of antibiotics in poultry diets. For broiler production, pasture- raised and free-range management systems have become more popular. However, challenges remain from exposure to disease-causing organisms and foodborne pathogens in these environments. Consequently, probiotics can be supplemented in poultry diets as commercial feed additives. The present review discusses the impacts of these probiotics on the performance of alternative poultry production systems for improving food safety and poultry health by mitigating pathogenic organisms and improving egg and meat quality and production.

Whole-genome analyses of extended-spectrum or AmpC β-lactamase-producing Escherichia coli isolates from companion dogs in Japan

The emergence and global spread of extended-spectrum or AmpC β-lactamase (ESBL/AmpC)-producing Enterobacteriaceae in companion animals have led to the hypothesis that companion animals might be reservoirs for cross-species transmission because of their close contact with humans. However, current knowledge in this field is limited; therefore, the role of companion animals in cross-species transmission remains to be elucidated. Herein, we studied ESBL/AmpC-producing Enterobacteriaceae, Escherichia coli in particular, isolated from extraintestinal sites and feces of companion dogs. Whole-genome sequencing analysis revealed that (i) extraintestinal E. coli isolates were most closely related to those isolated from feces from the same dog, (ii) chromosomal sequences in the ST131/C1-M27 clade isolated from companion dogs were highly similar to those in the ST131/C1-M27 clade of human origin, (iii) certain plasmids, such as IncFII/pMLST F1:A2:B20/bla_CTX-M-27, IncI1/pMLST16/bla_CTX-M-15, or IncI1/bla_CMY-2 from dog-derived E. coli isolates, shared high homology with those from several human-derived Enterobacteriaceae, (iv) chromosomal bla_CTX-M-14 was identified in the ST38 isolate from a companion dog, and (v) eight out of 14 tested ESBL/AmpC-producing E. coli isolates (i.e., ST131, ST68, ST405, and ST998) belonged to the human extraintestinal pathogenic E. coli (ExPEC) group. All of the bla-coding plasmids that were sequenced genome-wide were capable of horizontal transfer. These results suggest that companion dogs can spread ESBL/AmpC-producing ExPEC via their feces. Furthermore, at least some ESBL/AmpC-producing ExPECs and bla-coding plasmids can be transmitted between humans and companion dogs. Thus, companion dogs can act as an important reservoir for ESBL/AmpC-producing E. coli in the community.

The Phylogenetic Structure of Reptile, Avian and Uropathogenic Escherichia coli with Particular Reference to Extraintestinal Pathotypes

The impact of the Gram-negative bacterium Escherichia coli (E. coli) on the microbiomic and pathogenic phenomena occurring in humans and other warm-blooded animals is relatively well-recognized. At the same time, there are scant data concerning the role of E. coli strains in the health and disease of cold-blooded animals. It is presently known that reptiles are common asymptomatic carriers of another human pathogen, Salmonella, which, when transferred to humans, may cause a disease referred to as reptile-associated salmonellosis (RAS). We therefore hypothesized that reptiles may also be carriers of specific E. coli strains (reptilian Escherichia coli, RepEC) which may differ in their genetic composition from the human uropathogenic strain (UPEC) and avian pathogenic E. coli (APEC). Therefore, we isolated RepECs (n = 24) from reptile feces and compared isolated strains’ pathogenic potentials and phylogenic relations with the aforementioned UPEC (n = 24) and APEC (n = 24) strains. To this end, we conducted an array of molecular analyses, including determination of the phylogenetic groups of E. coli, virulence genotyping, Pulsed-Field Gel Electrophoresis-Restriction Analysis (RA-PFGE) and genetic population structure analysis using Multi-Locus Sequence Typing (MLST). The majority of the tested RepEC strains belonged to nonpathogenic phylogroups, with an important exception of one strain, which belonged to the pathogenic group B2, typical of extraintestinal pathogenic E. coli. This strain was part of the globally disseminated ST131 lineage. Unlike RepEC strains and in line with previous studies, a high percentage of UPEC strains belonged to the phylogroup B2, and the percentage distribution of phylogroups among the tested APEC strains was relatively homogenous, with most coming from the following nonpathogenic groups: C, A and B1. The RA-PFGE displayed a high genetic diversity among all the tested E. coli groups. In the case of RepEC strains, the frequency of occurrence of virulence genes (VGs) was lower than in the UPEC and APEC strains. The presented study is one of the first attempting to compare the phylogenetic structures of E. coli populations isolated from three groups of vertebrates: reptiles, birds and mammals (humans).

Genetic Features of Extended-Spectrum β-Lactamase-Producing Escherichia coli from Poultry in Mayabeque Province, Cuba

A total of 434 poultry cloacal samples were collected from seven different farms in different years (2013–2015) in the Cuban province of Mayabeque and analyzed for the presence of third-generation cephalosporin-resistant Escherichia coli (3GC-R-Ec). Sixty-two 3GC-R-Ec isolates were recovered in total from the farms, with detection rates of 2.9% in 2013, 10.3% in 2014, and 28.7% in 2015. Characterization of 32 3GC-R-Ec isolates revealed the presence of the extended-spectrum β-lactamase (ESBL) genes bla_CTX-M-1 (n = 27), bla_CTX-M-15 (n = 4), and bla_CTX-M-1 together with bla_LAP-2 (n = 1). The isolates also contained different proportions of genes conferring decreased susceptibility to sulfonamides (sul1, sul2, sul3), trimethoprim (dfrA1, dfrA7, dfrA12, dfrA14, dfrA17), tetracyclines (tet(A), tet(B)), aminoglycosides (aac(6′)-Ib-cr, strA, strB), chloramphenicol (cmlA1, floR), macrolides (mph(A), mph(D)), and quinolones (qnrS, qnrB, aac(6′)-Ib-cr) as well as mutations in the fluoroquinolone-resistance determining regions of GyrA (S83L, D87N, D87Y) and ParC (S80I, E84G). The isolates belonged to 23 different sequence types and to phylogroups A (n = 25), B1 (n = 5), and D (n = 2), and they contained plasmid-associated incompatibility groups FII, X1, HI1, HI2, N, FIA, and FIB. These findings reveal a genetically diverse population of multiresistant ESBL-producing E. coli in poultry farms in Cuba, which suggests multiple sources of contamination and the acquisition of antibiotic resistance genes.

Genomic diversity of Escherichia coli isolates from backyard chickens and guinea fowl in the Gambia

Chickens and guinea fowl are commonly reared in Gambian homes as affordable sources of protein. Using standard microbiological techniques, we obtained 68 caecal isolates of Escherichia coli from 10 chickens and 9 guinea fowl in rural Gambia. After Illumina whole-genome sequencing, 28 sequence types were detected in the isolates (4 of them novel), of which ST155 was the most common (22/68, 32 %). These strains span four of the eight main phylogroups of E. coli, with phylogroups B1 and A being most prevalent. Nearly a third of the isolates harboured at least one antimicrobial resistance gene, while most of the ST155 isolates (14/22, 64 %) encoded resistance to ≥3 classes of clinically relevant antibiotics, as well as putative virulence factors, suggesting pathogenic potential in humans. Furthermore, hierarchical clustering revealed that several Gambian poultry strains were closely related to isolates from humans. Although the ST155 lineage is common in poultry from Africa and South America, the Gambian ST155 isolates belong to a unique cgMLST cluster comprising closely related (38-39 alleles differences) isolates from poultry and livestock from sub-Saharan Africa - suggesting that strains can be exchanged between poultry and livestock in this setting. Continued surveillance of E. coli and other potential pathogens in rural backyard poultry from sub-Saharan Africa is warranted.

Genomic Investigation into the Virulome, Pathogenicity, Stress Response Factors, Clonal Lineages, and Phylogenetic Relationship of Escherichia coli Strains Isolated from Meat Sources in Ghana

Escherichia coli are among the most common foodborne pathogens associated with infections reported from meat sources. This study investigated the virulome, pathogenicity, stress response factors, clonal lineages, and the phylogenomic relationship of E. coli isolated from different meat sources in Ghana using whole-genome sequencing. Isolates were screened from five meat sources (beef, chevon, guinea fowl, local chicken, and mutton) and five areas (Aboabo, Central market, Nyorni, Victory cinema, and Tishegu) based in the Tamale Metropolis, Ghana. Following microbial identification, the E. coli strains were subjected to whole-genome sequencing. Comparative visualisation analyses showed different DNA synteny of the strains. The isolates consisted of diverse sequence types (STs) with the most common being ST155 (n = 3/14). Based Upon Related Sequence Types (eBURST) analyses of the study sequence types identified four similar clones, five single-locus variants, and two satellite clones (more distantly) with global curated E. coli STs. All the isolates possessed at least one restriction-modification (R-M) and CRISPR defence system. Further analysis revealed conserved stress response mechanisms (detoxification, osmotic, oxidative, and periplasmic stress) in the strains. Estimation of pathogenicity predicted a higher average probability score (P_score ≈ 0.937), supporting their pathogenic potential to humans. Diverse virulence genes that were clonal-specific were identified. Phylogenomic tree analyses coupled with metadata insights depicted the high genetic diversity of the E. coli isolates with no correlation with their meat sources and areas. The findings of this bioinformatic analyses further our understanding of E. coli in meat sources and are broadly relevant to the design of contamination control strategies in meat retail settings in Ghana.

Broiler Farms and Carcasses Are an Important Reservoir of Multi-Drug Resistant Escherichia coli in Ecuador

Antimicrobial resistance (AMR) is a major health threat for public and animal health in the twenty-first century. In Ecuador, antibiotics have been used by the poultry industry for decades resulting in the presence of multi-drug resistant (MDR) bacteria in the poultry meat production chain, with the consequent risk for public health. This study evaluated the prevalence of ESBL/AmpC and mcr genes in third-generation cephalosporin-resistant Escherichia coli (3GC-R E. coli) isolated from broiler farms (animal component), broiler carcasses (food component), and human enteritis (human component) in Quito-Ecuador. Samples were collected weekly from November 2017 to November 2018. For the animal, food, and human components, 133, 335, and 302 samples were analyzed, respectively. Profiles of antimicrobial resistance were analyzed by an automated microdilution system. Resistance genes were studied by PCR and Sanger sequencing. From all samples, 122 (91.7%), 258 (77%), and 146 (48.3%) samples were positive for 3GC-R E. coli in the animal, food, and human components, respectively. Most of the isolates (472/526, 89.7%) presented MDR phenotypes. The ESBL bla_CTX-M-55, bla_CTX-M-3, bla_CTX-M-15, bla_CTX-M-65, bla_CTX-M-27, and bla_CTX-M-14 were the most prevalent ESBL genes while bla_CMY-2 was the only AmpC detected gene. The mcr-1 gene was found in 20 (16.4%), 26 (10.1%), and 3 (2.1%) of isolates from animal, food, and human components, respectively. The implication of poultry products in the prevalence of ESBL/AmpC and mcr genes in 3GC-R must be considered in the surveillance of antimicrobial resistance.

Genetic Determinants of Resistance to Extended-Spectrum Cephalosporin and Fluoroquinolone in Escherichia coli Isolated from Diseased Pigs in the United States

Fluoroquinolones and cephalosporins are critically important antimicrobial classes for both human and veterinary medicine. We previously found a drastic increase in enrofloxacin resistance in clinical Escherichia coli isolates collected from diseased pigs from the United States over 10 years (2006 to 2016). However, the genetic determinants responsible for this increase have yet to be determined. The aim of the present study was to identify and characterize the genetic basis of resistance against fluoroquinolones (enrofloxacin) and extended-spectrum cephalosporins (ceftiofur) in swine E. coli isolates using whole-genome sequencing (WGS). bla_CMY-2 (carried by IncA/C2, IncI1, and IncI2 plasmids), bla_CTX-M (carried by IncF, IncHI2, and IncN plasmids), and bla_SHV-12 (carried by IncHI2 plasmids) genes were present in 87 (82.1%), 19 (17.9%), and 3 (2.83%) of the 106 ceftiofur-resistant isolates, respectively. Of the 110 enrofloxacin-resistant isolates, 90 (81.8%) had chromosomal mutations in gyrA, gyrB, parA, and parC genes. Plasmid-mediated quinolone resistance genes [qnrB77, qnrB2, qnrS1, qnrS2, and aac-(6)-lb′-cr] borne on ColE, IncQ2, IncN, IncF, and IncHI2 plasmids were present in 24 (21.8%) of the enrofloxacin-resistant isolates. Virulent IncF plasmids present in swine E. coli isolates were highly similar to epidemic plasmids identified globally. High-risk E. coli clones, such as ST744, ST457, ST131, ST69, ST10, ST73, ST410, ST12, ST127, ST167, ST58, ST88, ST617, ST23, etc., were also found in the U.S. swine population. Additionally, the colistin resistance gene (mcr-9) was present in several isolates. This study adds valuable information regarding resistance to critical antimicrobials with implications for both animal and human health.

IMPORTANCE Understanding the genetic mechanisms conferring resistance is critical to design informed control and preventive measures, particularly when involving critically important antimicrobial classes such as extended-spectrum cephalosporins and fluoroquinolones. The genetic determinants of extended-spectrum cephalosporin and fluoroquinolone resistance were highly diverse, with multiple plasmids, insertion sequences, and genes playing key roles in mediating resistance in swine Escherichia coli. Plasmids assembled in this study are known to be disseminated globally in both human and animal populations and environmental samples, and E. coli in pigs might be part of a global reservoir of key antimicrobial resistance (AMR) elements. Virulent plasmids found in this study have been shown to confer fitness advantages to pathogenic E. coli strains. The presence of international, high-risk zoonotic clones provides worrisome evidence that resistance in swine isolates may have indirect public health implications, and the swine population as a reservoir for these high-risk clones should be continuously monitored.

International clones of extended-spectrum β-lactamase (CTX-M)-producing Escherichia coli in peri-urban wild animals, Brazil

CTX-M-type extended-spectrum β-lactamase (ESBL)-producing Escherichia coli clones have been increasingly reported worldwide. In this regard, although discussions of transmission routes of these bacteria are in evidence, molecular data are lacking to elucidate the epidemiological impacts of ESBL producers in wild animals. In this study, we have screened 90 wild animals living in a surrounding area of São Paulo, the largest metropolitan city in South America, to monitor the presence of multidrug-resistant (MDR) Gram-negative bacteria. Using a genomic approach, we have analysed eight ceftriaxone-resistant E. coli. Resistome analyses revealed that all E. coli strains carried blaCTX-M -type genes, prevalent in human infections, besides other clinically relevant resistance genes to aminoglycosides, β-lactams, phenicols, tetracyclines, sulphonamides, trimethoprim, fosfomycin and quinolones. Additionally, E. coli strains belonged to international sequence types (STs) ST38, ST58, ST212, ST744, ST1158 and ST1251, and carried several virulence-associated genes. Our findings suggest spread and adaptation of international clones of CTX-M-producing E. coli beyond urban settings, including wildlife from shared environments.

Country Income Is Only One of the Tiles: The Global Journey of Antimicrobial Resistance among Humans, Animals, and Environment

Antimicrobial resistance (AMR) is one of the most complex global health challenges today: decades of overuse and misuse in human medicine, animal health, agriculture, and dispersion into the environment have produced the dire consequence of infections to become progressively untreatable. Infection control and prevention (IPC) procedures, the reduction of overuse, and the misuse of antimicrobials in human and veterinary medicine are the cornerstones required to prevent the spreading of resistant bacteria. Purified drinking water and strongly improved sanitation even in remote areas would prevent the pollution from inadequate treatment of industrial, residential, and farm waste, as all these situations are expanding the resistome in the environment. The One Health concept addresses the interconnected relationships between human, animal, and environmental health as a whole: several countries and international agencies have now included a One Health Approach within their action plans to address AMR. Improved antimicrobial usage, coupled with regulation and policy, as well as integrated surveillance, infection control and prevention, along with antimicrobial stewardship, sanitation, and animal husbandry should all be integrated parts of any new action plan targeted to tackle AMR on the Earth. Since AMR is found in bacteria from humans, animals, and in the environment, we briefly summarize herein the current concepts of One Health as a global challenge to enable the continued use of antibiotics.

Genomic landscape of multi-drug resistant avian pathogenic Escherichia coli recovered from broilers

Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), constitutes a substantial burden to the poultry industry worldwide. APEC has been extensively characterized throughout the world, however, less is known about the genetic background of APEC isolates from Pakistan. In this study, a total of 75 E. coli isolates from colibacillosis affected dead broiler birds in Pakistan were subjected to whole genome sequencing followed by in-silico characterization. These isolates were investigated for virulence and resistance genotypes, serotypes, multi-locus sequence types, plasmid replicon types and single nucleotide polymorphism-based core genome phylogeny. Among the APEC isolates investigated, 14 different sequence types were identified with ST117 (16 %), ST2847 (10.7 %) and ST48 (5.3 %) being the most prevalent. Of the 28 different serotypes identified in this study, O1, O2 and O78 serotypes accounted for 25.3 % of the APEC isolates. The most frequently identified virulence-associated genes (VAGs) were increased serum survival gene; iss (100 %), glutamate decarboxylase; gad (92 %) and the siderophore receptor; iroN (81.3 %). According to the previously established definition, 72 % of isolates fell within the highly pathogenic APEC category by possessing a combination of VAGs; iss, iroN, iutA, hlyF and ompT simultaneously. Of the 75 APEC isolates, 89.3 % contained the genes predicted to encode resistance against aminoglycosides, tetracyclines and sulfonamides. Notably, the acquired colistin resistance gene mcr-1 was found in 38.7 % of the APEC isolates. Our findings reveal a diverse genetic background and high virulence and resistance potentials for APEC isolates in Pakistan.

Widespread high-risk clones of multidrug-resistant extended-spectrum β-lactamase-producing Escherichia coli B2-ST131 and F-ST648 in public aquatic environments

Aquatic environments are considered a reservoir for the dissemination of multidrug-resistant (MDR) bacteria, principally Escherichia coli, with the consequent spread of acquired antimicrobial resistance genes (ARGs). Widespread high-risk clones of MDR E. coli are responsible for human infections worldwide. This study aimed to characterise, through whole-genome sequencing (WGS), isolates of MDR E. coli harbouring ARGs obtained from public aquatic environments in Brazil. MDR E. coli isolates were obtained from rivers, streams and lakes that presented different Water Quality Index records and were submitted to WGS. The resistome, mobilome and virulome showed a great diversity of ARGs, plasmids and virulence genes, respectively. In addition, mutations in the quinolone resistance-determining regions of GyrA, ParC and ParE as well as several metal resistance genes (MRGs) and antibacterial biocide resistance genes (ABGs) were detected. Typing and subtyping of MDR E. coli revealed different lineages, with two belonging to widespread high-risk clones (i.e. B2-ST131-fimH30 and F-ST648-fimH27), which are grouped by core genome multilocus sequence typing (cgMLST) in clusters with E. coli lineages obtained from different sources distributed worldwide. MDR bacteria carrying MRGs and ABGs have emerged as a global human and environmental health problem. Detection of widespread high-risk clones calls for attention to the dissemination of fluoroquinolone-resistant QnrS1- and CTX-M-producing E. coli lineages associated with human infections in public aquatic environments.

ST131 fimH22 Escherichia coli isolate with a blaCMY-2/IncI1/ST12 plasmid obtained from a patient with bloodstream infection: highly similar to E. coli isolates of broiler origin

OBJECTIVES

This study compares the genome of an ST131 CMY-2-producing Escherichia coli isolate from a Danish patient with other ST131 CMY-2-producing E. coli isolates of both human and animal origin.

METHODS

In 2016, an ST131 CMY-2-producing E. coli isolate (ESBL20160056) was obtained from a patient with a bloodstream infection. The genome of the ESBL20160056 isolate was compared with genomes from six ST131 CMY-2-producing E. coli isolates obtained from broiler meat imported to Denmark, 15 ST131 CMY-2-producing E. coli isolates obtained from Enterobase (http://enterobase.warwick.ac.uk) and two ST131 CMY-2-producing E. coli from European collaborators. The plasmid from ESBL20160056 was sequenced using a MinION Mk1B (Oxford Nanopore Technologies).

RESULTS

The E. coli isolate from the Danish patient clustered together with 13 other fimH22 ST131 CMY-2-producing E. coli isolates in a distinct clade. The clade consisted of genomes from six E. coli isolates from humans collected in Denmark, Spain, Cambodia and the USA, six E. coli isolates obtained from broiler meat samples imported to Denmark from France, the Netherlands and Germany, and two E. coli isolates obtained from broilers in Belgium and Luxembourg. The 101.5 kb plasmid with blaCMY-2 from ESBL20160056 had an IncI1 replicon and belonged to ST12 using the plasmid MLST scheme. In total, 10 of the 14 ST131 E. coli isolates belonging to the fimH22 clade carried an IncI1 ST12 plasmid with blaCMY-2.

CONCLUSIONS

From our data, it seems plausible that the ST131 fimH22 CMY-2-producing E. coli isolate obtained from the Danish patient could have a zoonotic broiler origin.

Antimicrobial Resistance, Genetic Diversity and Multilocus Sequence Typing of Escherichia coli from Humans, Retail Chicken and Ground Beef in Egypt

Contamination of retail foods with foodborne pathogens, particularly the antimicrobial resistant ones, poses a persistent threat to human health. There is a dearth of information about the overlapping Escherichia coli (E. coli) lineages circulating among retail foods and humans in Egypt. This study aimed to determine the clonal diversity of 120 E. coli isolates from diarrheic patients (n = 32), retail chicken carcasses (n = 61) and ground beef (n = 27) from Mansoura, Egypt using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Simpson’s index of diversity was calculated to compare the results of both typing methods. Antimicrobial resistance phenotypes, genotypes and phylogrouping of the isolates were also determined. Higher frequencies of antimicrobial resistance were found among chicken isolates compared to beef and human isolates; regardless of isolate source, the predominant antimicrobial resistances were found against ampicillin (87/120, 72.5%), tetracycline and sulfisoxazole (82/120, 68.3%, each), and streptomycin (79/120, 65.8%). None of the isolates displayed resistance to meropenem. The prevalent genes detected were tetA (64.2%), bla_TEM (62.5%), sul1 (56.7%), floR (53.3%), sul2 (50%), strB (48.3%) and strA (47.5%) corresponding with resistance phenotypes. Alarmingly, bla_CTX was detected in 63.9% (39/61) of chicken isolates. The majority of E. coli isolates from humans (90.6%), beef (81.5%) and chicken (70.5%) belonged to commensal phylogroups (A, B1, C). Using PFGE analysis, 16 out of 24 clusters (66.7%) contained isolates from different sources at a similarity level ≥75%. MLST results assigned E. coli isolates into 25, 19 and 13 sequence types (STs) from chicken, human and beef isolates, respectively. Six shared STs were identified including ST1011, ST156, ST48, ST224 (chicken and beef), ST10 (human and chicken) and ST226 (human and beef). Simpson’s index of diversity was higher for MLST (0.98) than PFGE (0.94). In conclusion, the existence of common genetic determinants among isolates from retail foods and humans in Egypt as well as the circulation of shared STs indicates a possible epidemiological link with potential zoonotic hazards.

Whole Genome Sequencing of Escherichia coli From Store-Bought Produce

The role of agriculture in the transfer of drug resistant pathogens to humans is widely debated and poorly understood. Escherichia coli is a valuable indicator organism for contamination and carriage of antimicrobial resistance (AMR) in foods. Whilst whole genome sequences for E. coli from animals and associated meats are common, sequences from produce are scarce. Produce may acquire drug resistant E. coli from animal manure fertilizers, contaminated irrigation water and wildlife, particularly birds. Whole genome sequencing was used to characterize 120 tetracycline (TET) resistant E. coli from store-bought, ready-to-eat cilantro, arugula and mixed salad from two German cities. E. coli were recovered on the day of purchase and after 7 days of refrigeration. Cilantro was far more frequently contaminated with TET-resistant E. coli providing 102 (85%) sequenced strains. Phylogroup B1 dominated the collection (n = 84, 70%) with multi-locus sequence types B1-ST6186 (n = 37, 31%), C-ST165 (n = 17, 14%), B1-ST58 (n = 14, 12%), B1-ST641 (n = 8, 7%), and C-ST88 (n = 5, 4%) frequently identified. Notably, seven strains of diverse sequence type (ST) carried genetic indicators of ColV virulence plasmid carriage. A number of previously identified and novel integrons associated with insertion elements including IS26 were also identified. Storage may affect the lineages of E. coli isolated, however further studies are needed. Our study indicates produce predominantly carry E. coli with a commensal phylogroup and a variety of AMR and virulence-associated traits. Genomic surveillance of bacteria that contaminate produce should be a matter of public health importance in order to develop a holistic understanding of the environmental dimensions of AMR.

Identification of antimicrobial resistant bacteria from plant-based food products imported into Canada

The role of plant-based foods in the epidemiology of antimicrobial resistance has been inadequately studied. In this investigation, resistant organisms from vegetables, fruits and spices imported into Canada were identified and characterized. A total of 143 products imported from primarily Asian and African countries were purchased from international markets in Saskatoon, Saskatchewan. Samples were selectively cultured for bacterial species where resistance is known to be emerging. The proportions of samples positive for each organism were as follows: E. coli (n = 13, 9.1%), Salmonella spp. (n = 2, 1.4%), ESBL producing Enterobacter spp. (n = 2, 1.4%) and K. pneumoniae (n = 2, 1.4%), S. aureus (n = 7, 4.9%) and Enterococcus spp. (n = 66, 46.2%). Antimicrobial minimum inhibitory concentrations were determined by broth micro-dilution and agar-dilution. Based on the susceptibility of each organism, isolates were screened for resistance genes (β-lactamases and plasmid mediated quinolones resistance determinants) by PCR. Extended-spectrum β-lactamase producing Enterobacteriaceae and methicillin resistant S. aureus (MRSA) were identified from 6/143 (4.2%) and 2/143 (1.4%) of samples respectively. The qnrB, qnrS and aac(6')-Ib-cr plasmid mediated quinolone resistance determinants were identified in 2/143 (1.4%) of samples tested. None of the Enterobacteriaceae isolates were resistant to meropenem or colistin. Similarly, all Enterococcus isolates remained susceptible to ampicillin, penicillin and vancomycin. Finding multi-drug resistant bacteria which are frequently isolated from human infections is concerning, although the contribution of the global food trade to the dissemination of resistance remains cryptic. These results suggest that imported plant-based foods may be an underappreciated source of clinically relevant resistant organisms. Further study is required to address these gaps in our understanding of the epidemiology of resistance, and the magnitude of the risk posed to human health by these organisms.

High occurrence of CMY-2-type beta-lactamase-producing Escherichia coli among broiler flocks in Turkey

In this study, the prevalence of ESBL/pAmpC-producing Escherichia coli and their molecular characterization from cloacal swab samples were investigated. All samples were obtained from broiler flocks that are located in Hatay, Adana, and Mersin provinces of Turkey. Antimicrobial susceptibilities of the isolates were determined by disk diffusion method following the CLSI criteria. Genetic mechanisms mediating resistance in ESBL/pAmpC-producing E. coli isolates were identified by polymerase chain reaction (PCR) and followed by DNA sequencing. Phylogenetic groups and plasmid replicon types of the isolates were also investigated by PCR. The clonal relationship of selected isolates was investigated by enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus sequence typing (MLST) method. Of 430 cloacal swab samples, 154 (35.8%) were positive for ESBL/pAmpC-producing E. coli. The ESBL/pAmpC type beta-lactamases were as follows: CMY-2 (n = 46), CMY-2 + TEM-1b (n = 63), SHV-12 (n = 5), SHV-12 + TEM-1b (n = 12), CTX-M-3 (n = 14), CTX-M-3 + TEM-1b (n = 1), CTX-M-15 (n = 4), CTX-M-15 + TEM-1b (n = 4), and CTX-M-1 (n = 3). Moreover, various rates of resistance to different antimicrobials were determined such as nalidixic acid (92.9%), ciprofloxacin (76%), sulfamethoxazole-trimethoprim (78.6%), tetracycline (73.4%), streptomycin (52.6%), chloramphenicol (44.2%), kanamycin (27.9%), tobramycin (24.7%), gentamicin (19.5%), and amikacin (0.6%). Furthermore, 148 (96.1%) isolates were found to be MDR. The ESBL/pAmpC-producing isolates were distributed into the following phylogroups: E (n = 61), B1 (n = 30), F (n = 20), A (n = 19), B2 (n = 11), D (n = 10), and C (n = 3). ERIC-PCR analysis showed 51 unrelated patterns. Out of the 28 selected isolates, the following sequence types (STs) were detected: ST354 (n = 3), ST114 (n = 3), ST5696 (n = 2), ST156 (n = 2), ST174 (n = 2), ST362 (n = 2), ST157 (n = 2), ST5114 (n = 2), ST6635, ST539, ST457, ST1640, ST95, ST5843, ST1158, ST10, ST648, and ST4248. The results of the current study revealed that broilers in Turkey are important reservoir of ESBL/pAmpC-producing E. coli, which suggest that these agents have a great potential of transmission to humans by food chain or direct contact.

Whole genome sequence analysis of antimicrobial resistance genes, multilocus sequence types and plasmid sequences in ESBL/AmpC Escherichia coli isolated from broiler caecum and meat

Plasmid-encoded extended-spectrum β-lactamase and AmpC gene-carrying Escherichia coli (ESBL/AmpC E. coli) is an increasing cause of human infections worldwide. Increasing carbapenem and colistin resistance further complicate treatment of these infections. The aim of this study was to assess the occurrence of ESBL/AmpC E. coli in different broiler flocks and farms, as well as in broiler meat, in a country with no antimicrobial usage in broiler production. An additional goal was to assess the genetic characteristics of ESBL/AmpC E. coli isolates by using whole genome sequencing (WGS). Altogether 520 caecal swabs and 85 vacuum-packed broiler meat samples were investigated at the slaughterhouse level. WGS of the bacterial isolates revealed acquired antimicrobial resistance (AMR) genes, multilocus sequence types (MLST) and plasmid sequences. ESBL/AmpC E. coli was identified in 92 (18%) of the caecum and 27 (32%) of the meat samples. ESBL/AmpC E. coli-carrying birds derived from six (33%) out of 18 farms. Of the two bla_ESBL/AmpC genes detected by PCR, bla_CMY-2 (96%) was predominant over bla_CTX-M-1 (4%). Furthermore, WGS revealed an additional AMR gene sul2. Carbapenemase, colistin, and other AMR genes were not detected from the isolates of either the caecal or meat samples. Altogether seven MLSTs (ST101, ST117, ST212, ST351, ST373, ST1594 and an unknown ST) and a variety of different plasmid sequences (IncB/O/K/Z, IncI1, IncFII, IncII, IncFIB, IncFIC, IncX1 and an additional set of Col-plasmids) were detected. This is the first study on genomic epidemiology of ESBL/AmpC E. coli on broiler farms and flocks with no antimicrobial usage, by using WGS analysis. Results show that ESBL/AmpC E. coli occurrence is common both in the caecum and in the packaged meat. However, compared to other European countries, the occurrence is low and the presence of AMR genes other than bla_CMY-2 and bla_CTX-M-1 is rare. More studies are needed to understand the ESBL/AmpC E. coli occurrence in broiler production to prevent the meat from contamination during slaughter and processing, thereby also preventing zoonotic transmission of ESBL/AmpC E. coli. Additionally, more studies are needed to understand the ecology and fitness cost of Enterobacteriaceae plasmids in animal production in order to prevent their acquisition of plasmid-encoded antimicrobial resistance genes such as carbapenem and colistin resistance genes, as this would pose a great hazard to food safety.

High clonal diversity of multidrug-resistant and extended spectrum beta-lactamase-producing Escherichia coli in a wastewater treatment plant

Increasing beta-lactam resistance has led to the exploration of different places, such as wastewater treatment plants (WWTPs) which have been considered to be reservoirs and sources of bacterial resistance. This work aims to determine the presence of beta-lactamase-producing-Enterobacteriaceae in different points of a WWTP in Colombia. Six samplings were carried out in 2017 in the raw influent, aeration tanks, recycled sludge and final effluent of a WWTP. The beta-lactamase-producing-Enterobacteriaceae were detected and identified using phenotypic and molecular methods. Of the 353 isolates included, 28.3% corresponded to enterobacteria. The most frequent microorganisms were Escherichia coli (83%), Citrobacter freundii (11%) and Enterobacter cloacae complex (4%). The 97% of enterobacteriaceae had at least one beta-lactamase, and the most prevalent were the bla_TEM (43.8%) and bla_CTX-M-1group (35.8%) which were detected specially in recycled sludge and final effluent sample points. High percentage of multidrug resistance (to beta-lactams and non-beta-lactam antibiotics) was detected in E. coli (63.2%). Additionally, the typing by PFGE and MLST showed high genotypic diversity and the presence of the successful ST131 clone, globally spread. This work highlights the strong role of E. coli as a vector for the dissemination of resistance and the beta-lactamases in aquatic environments.

Draft Genome Sequence of an Escherichia coli Sequence Type 155 Strain Isolated from Sewage in Kerala, India

We report the draft genome sequence of Escherichia coli ASBT-1, a representative of E. coli sequence type 155 (ST155), obtained from India. Considering the known wide variety of pathogenic and antibiotic resistance potentials, this strain should be of great interest for detailed comparative genomic analysis.

Phylogenomic Investigation of IncI1-Iγ Plasmids Harboring bla CMY-2 and bla SHV-12 in Salmonella enterica and Escherichia coli in Multiple Countries

The objective of this study was to elucidate the genetic and evolutionary relatedness of bla _CMY-2- and bla _SHV-12-carrying IncI1-Iγ plasmids. Phylogenomic analysis based on core genome alignments and gene presence/absence was performed for different IncI1-Iγ sequence types (STs). Most IncI1-Iγ/ST12 and IncI1-Iγ/ST231 plasmids had near-identical core genomes. The data suggest that widely occurring bla _CMY-2-carrying IncI1-Iγ/ST12 plasmids originate from a common ancestor. In contrast, bla _SHV-12 was inserted independently into different IncI1-Iγ/ST231-related plasmids.

Antimicrobial Resistance and Potential Pathogenicity of Escherichia coli Isolates from Healthy Broilers in Québec, Canada

Antimicrobial resistance (AMR) is a global health issue, particularly when it affects critically important antimicrobials such as third-generation cephalosporins (3GC). The objective of this study was to characterize Escherichia coli isolates from healthy chickens in Québec in farms where ceftiofur has been administered to chickens in ovo over a long period with regard to their AMR, multidrug resistance (MDR), potential virulence, clonality, and possession of plasmids of the incompatibility groups carrying extended-spectrum beta-lactamases (ESBLs)/AmpC genes. More than 62% of indicator isolates were MDR with resistance observed for each of the nine classes of antimicrobials tested by disk diffusion. 3GC resistance was encoded by the bla_CMY-2 gene (26.7% in indicator isolates), whereas bla_CTX-M was only detected in isolates selected after supplementation with ceftriaxone (3 bla_CTX-M-1 isolates). Examination of bla_CMY-2-positive isolates by pulsed-field gel electrophoresis showed clustering of isolates originating from different floors of the livestock building within farms. The bla_CMY-2 gene was carried on replicon plasmids FIB, I1, K/B, and B/O, whereas bla_CTX-M-1 gene was located on I1 as demonstrated by transformation experiments; some of these plasmids cotransferred nonsusceptibility against tetracycline or sulfonamides. In addition, six isolates, of which three were AmpC-producers, were defined as potential human extraintestinal pathogenic E. coli. In summary, this study showed that ESBLs/AmpC-producing E. coli isolates from apparently healthy chickens in Québec, Canada predominantly possess bla_CMY-2 rather than bla_CTX-M maybe because of the in ovo use of ceftiofur to prevent omphalitis and may be spread through clones or plasmids, and that some of these isolates could be capable of infecting humans.

Characterization of cefotaxime resistant Escherichia coli isolated from broiler farms in Ecuador

Antimicrobial resistance (AR) is a worldwide concern. Up to a 160% increase in antibiotic usage in food animals is expected in Latin American countries. The poultry industry is an increasingly important segment of food production and contributor to AR. The objective of this study was to evaluate the prevalence, AR patterns and the characterization of relevant resistance genes in Extended Spectrum β-lactamases (ESBL) and AmpC-producing E. coli from large poultry farms in Ecuador. Sampling was performed from June 2013 to July 2014 in 6 slaughterhouses that slaughter broilers from 115 farms totaling 384 flocks. Each sample of collected caeca was streaked onto TBX agar supplemented with cefotaxime (3 mg/l). In total, 176 isolates were analyzed for AR patterns by the disk diffusion method and for blaCTX-M, blaTEM, blaCMY, blaSHV, blaKPC, and mcr-1 by PCR and sequencing. ESBL and AmpC E. coli were found in 362 flocks (94.3%) from 112 farms (97.4%). We found that 98.3% of the cefotaxime-resistant isolates were multi-resistant to antibiotics. Low resistance was observed for ertapenem and nitrofurantoin. The most prevalent ESBL genes were the ones belonging to the blaCTX-M group (90.9%), specifically the blaCTX-M-65, blaCTX-M-55 and blaCTX-M-3 alleles. Most of the AmpC strains presented the blaCMY-2 gene. Three isolates showed the mcr-1 gene. Poultry production systems represent a hotspot for AR in Ecuador, possibly mediated by the extensive use of antibiotics. Monitoring this sector in national and regional plans of AR surveillance should therefore be considered.

Prevalence of antimicrobial resistance and potential pathogenicity, and possible spread of third generation cephalosporin resistance, in Escherichia coli isolated from healthy chicken farms in the region of Dakar, Senegal

Escherichia coli is a normal inhabitant of the intestinal microbiota of chickens, a small proportion of which may be avian pathogenic E. coli (APEC) or potential extraintestinal pathogenic E. coli (ExPEC), capable of causing disease in humans. These E. coli may also be resistant to antimicrobials of critical importance in human or veterinary health. This study aims to 1) determine the prevalence of antimicrobial resistance (AMR) and resistance genes, multidrug resistance (MDR), chromosomal mechanisms of quinolone-resistance and virulence profiles of E. coli isolated from healthy chicken farms in the region of Dakar, Senegal, 2) investigate the spread of third-generation cephalosporins (3GC) resistance in E. coli isolated from healthy chicken farms with respect to virulence and resistance genes, serogroups, Pulsed-Field Gel Electrophoresis (PFGE), phylogenetic groups, plasmid types and transferability and 3) determine whether nonsusceptibility against 3GC on farms could be linked to risk factors. More than 68% of isolates from environmental faecal and drinking water samples, carcasses and carcass washes collected on 32 healthy chicken farms were multidrug resistant (MDR), resistance to antimicrobials critical in human health (3GC or ciprofloxacin) being found in all types of samples. Ciprofloxacin resistance was due to mutations in the gyrA and parC genes, 95% of tested farms harboring isolates carrying three mutations, in gyrA (Ser83Ile and Asp87Asn) and parC (Ser80Ile). Nine of the 32 farms (28.1%) demonstrated the presence of one or more 3GC-nonsusceptible indicator isolates but none of the potential risk factors were significantly associated with this presence on farms. Following ceftriaxone enrichment, presumptive extended-spectrum beta-lactamase/AmpC-beta-lactamase (ESBL/AmpC)-producer isolates were found in 17 of the 32 farms. 3GC resistance was mediated by blaCMY-2 or blaCTX-M genes, blaCTX-M being of genotypes blaCTX-M-1, blaCTX-M-8 and for the first time in chickens in Senegal, the genotype blaCTX-M-15. Clonally related ESBL/AmpC-producer isolates were found on different farms. In addition, blaCTX-M genes were identified on replicon plasmids I1 and K/B and blaCMY-2 on K/B, I1 and B/O. These plasmids were found in isolates of different clusters. In addition, 18 isolates, some of which were ESBL/AmpC-producers, were defined as potential human ExPEC. In conclusion, E. coli isolates potentially pathogenic for humans and demonstrating MDR, with resistance expressed against antimicrobials of critical importance in human health were found in healthy chickens in Senegal. Our results suggest that both clonal spreading and horizontal gene transfer play a role in the spread of 3GC-resistance and that chickens in Senegal could be a reservoir for AMR and ExPEC for humans. These results highlight the importance of raising awareness about compliance with biosecurity measures and prudent use of antimicrobials.

Direct vertical transmission of ESBL/pAmpC-producing Escherichia coli limited in poultry production pyramid

Extended-spectrum beta-lactamase (ESBL) and plasmidic AmpC (pAmpC) producing Escherichia coli are found in the poultry production even without antibiotic use. The spread of these bacteria has been suggested to occur via imported parent birds, enabling transmission to production level broilers vertically via eggs. We studied transmission of ESBL/pAmpC-producing E. coli and E. coli without antibiotic selection by sampling imported parent birds (n = 450), egg surfaces prior to and after the incubation period (n = 300 and n = 428, respectively) and the laying house environment (n = 20). Samples were additionally taken from embryos (n = 422). To study the prevention of transmission, a competitive exclusion (CE) solution was added onto freshly laid eggs prior to incubation period (n = 150). Results showed carriage of ESBL/pAmpC-producing E. coli in parent birds (26.7%), the environment (5%) and egg surfaces before the incubation period (1.3%), but not from egg surfaces or embryos after the incubation period. Whole genome sequencing revealed ESBL/pAmpC-producing E. coli isolates belonging to clonal lineages ST429 and ST2040. However, the finding of E. coli cultured without antibiotic selection in two (2.2%) embryos strengthens the need to study E. coli transmission in poultry production in more depth. Since ESBL/pAmpC-producing E. coli seem not to persist on egg surfaces, there is no need to use CE solution ex ovo as a prevention method. The results indicate that other routes, such as for example transmission through fomites or horizontal gene transfer by other bacterial species, could be more important than vertical transmission in the spread of resistance in broiler production.

Plasmid-mediated colistin resistance gene mcr-1 in Escherichia coli and Klebsiella pneumoniae isolated from market retail fruits in Guangzhou, China

Background

As a result of the growing prevalence of the plasmid-mediated mobile colistin resistance gene mcr-1 among Gram-negative bacteria, the surveillance of mcr-1 has been globally applied. In our study, we aimed to shed light on the possibility of transmission of mcr-1-resistant isolates through market retail fruits.

Methods and results

Herein, 133 different fruit surface samples were collected and screened for the different MCR variants (mcr-1 to mcr-8) using PCR and confirmed with sequencing. We identify for the first time mcr-1-carrying Escherichia coli and Klebsiella pneumoniae from market retail fruits in Guangzhou, China. Minimum inhibitory concentrations were detected by the broth microdilution method. Liquid mating was performed to check the transferability of the mcr-1 gene. Pulsed field gel electrophoresis analysis of S1 nuclease-digested DNA and Southern blotting were performed to check the location of the mcr-1 gene. Then, whole-genome sequencing and in silico multilocus sequence typing analysis were performed.

Conclusion

We showed that E. coli GB110 can mediate the spreading of antibiotic resistance genes through the food chain, while K. pneumoniae GB015 was considered to be the progenitor of the most successful multidrug-resistant clone. Since fruits are usually consumed fresh, this may serve as a direct source of mcr-1-producing bacteria in humans that requires prompt surveillance and intervention to limit the spread of resistance.