Escherichia coli ST117: exploring the zoonotic hypothesis.

Extraintestinal pathogenic Escherichia coli (ExPEC) can lead to severe infections, with additional risks of increasing antimicrobial resistance rates. Genotypic similarities between ExPEC and avian pathogenic E. coli (APEC) support a possible role for a poultry meat reservoir in human disease. Some genomic studies have been done on the ST117 lineage which contaminates poultry meat, carries multidrug resistance, can be found in the human intestinal microbiota, and causes human extraintestinal disease. This study analyzed the genomes of 61 E. coli from Brazilian poultry outbreaks focusing on ST117, to further define its possible zoonotic characteristics by genotypic and phylogenomic analyses, along with 1,699 worldwide ST117 isolates originating from human, animal, and environment sources. A predominance of ST117 was detected in the Brazilian isolates (n = 20/61) frequently carrying resistance to critical antibiotics (>86%) linked to IncFII, IncI1, or IncX4 replicons. High similarities were found between IncX4 from Brazilian outbreaks and those from E. coli recovered from imported Brazilian poultry meat and human clinical cases. The ST117 phylogeny showed non-specificity according to host and continent and an AMR index score indicated the highest resistance in Asia and South America, with the latter statistically more resistant and overrepresented with resistance to extended-spectrum beta-lactamases (ESBL). Most ST117 human isolates were predicted to have a poultry origin (93%, 138/148). In conclusion, poultry is a likely source for zoonotic ExPEC strains, particularly the ST117 lineage which can also serve as a reservoir for resistance determinants against critical antibiotics encoded on highly transmissible plasmids. IMPORTANCE: Certain extraintestinal pathogenic Escherichia coli (ExPEC) are particularly important as they affect humans and animals. Lineages, such as ST117, are predominant in poultry and frequent carriers of antibiotic resistance, presenting a risk to humans handling or ingesting poultry products. We analyzed ExPEC isolates causing outbreaks in Brazilian poultry, focusing on the ST117 as the most detected lineage. Genomic comparisons with international isolates from humans and animals were performed describing the potential zoonotic profile. The Brazilian ST117 isolates carried resistance determinants against critical antibiotics, mainly on plasmids, in some cases identical to those carried by international isolates. South American ST117 isolates from all sources generally exhibit more resistance, including to critical antibiotics, and worldwide, the vast majority of human isolates belonging to this lineage have a predicted poultry origin. As the world's largest poultry exporter, Brazil has an important role in developing strategies to prevent the dissemination of multidrug-resistant zoonotic ExPEC strains.

Antibiotic resistant Escherichia coli strains in healthy pets from Tamaulipas, Mexico.

Antibiotic resistance constitutes a significant public health challenge, with diverse reservoirs of resistant bacteria playing pivotal roles in their dissemination. Among these reservoirs, pets are carrying antibiotic-resistant strains. The objective of this study was to assess the resistance profiles of Escherichia coli, and the prevalence of extended-spectrum ß-lactamase (ESBL) producing E. coli strains in dogs and cats from Tamaulipas, Mexico. A total of 300 stool samples (150 dogs and 150 cats) from healthy pets were subjected to analysis. Antibiotic susceptibility testing and the identification of ESBLs were carried out by disc diffusion method. The presence of resistance genes, class 1, 2, and 3 integrons (intI1, intI2, and intI3) and phylogroups was determined by PCR analysis. The findings reveal that 42.6% (128/300) of the strains exhibited resistance to at least one of the eight antibiotics assessed, and 18.6% (56/300) demonstrated multidrug resistance (MDR), that distributed across 69 distinct resistance patterns. Altogether 2.6% of E. coli strains (8/300) were confirmed as TEM and CTX-M type ESBL producers. These outcomes underscore the roles of dogs and cats in Tamaulipas as reservoirs for the dissemination of MDR and/or ESBL strains. The results underscore the necessity for conducting prevalence studies on ESBL-producing E. coli, forming a foundation for comprehending the present scenario and formulating strategies for the control and mitigation of this issue.

ESBL-producing Escherichia coli prevalence and sharing across seabirds of central Chile.

Antimicrobial resistance (AMR) is a major global public threat, now largely reported in natural environments. Seabirds are carriers of extended-spectrum ß-lactamase-producing Escherichia coli (ESBL-E. coli), but different foraging and breeding behaviour could impact ESBL-E. coli circulation. We compared the prevalence and genetic determinants of ESBL-E. coli from resident Kelp gulls (Larus dominicanus, Ld), migratory Franklin's gulls (Larus pipixcan, Lp), and endemic Peruvian pelicans (Pelecanus thagus, Pt) from the Humboldt Current Ecosystem (HCE) of central Chile. From 2020 to 2022, we collected 699 fresh faecal samples (Ld = 449, Lp = 116, Pt = 134), and isolated 271 ESBL-E. coli (39 %). Whole-genome-sequencing (WGS) was performed on 85 E. coli selected isolates to identify their Sequence Type (ST), AMR genes, virulence genes, mobile genetic elements (MGE), and to assess potential interspecies transmission. ESBL-genes were detected in the remaining ESBL-E. coli isolates by PCR. ESBL-E. coli prevalence in Ld (46 % [CI: 42-51 %]) and Pt (34 % [CI: 27-43 %]) was higher than in Lp (15 % [CI: 9-22 %]). WGS revealed 41 ESBL-E. coli STs including pandemic clones ST10, ST58, ST131 and ST410. The blaCTX-M-1 and blaCTX-M-15 genes were the most prevalent among ESBL genes, and were mostly associated with MGE IncI1-I(Alpha) and ISEc9. We also report the pAmpC blaCMY-2 gene associated to MGE Inc1-I(Alpha) and IS640 in two E. coli from a Ld and a Lp. Eight ESBL-E. coli of the same ST were shared by at least two seabird species, including ST10 (Ld and Pt); ST88, ST410 and ST617 (Pt and Lp); ST38, ST58, ST131, and SST1722 (three species). Single nucleotide polymorphism (SNP) phylogenetic analyses of ST38, ST617 and ST1722 showed a low difference of SNPs between STs found in different seabird species, suggesting ESBL-E. coli clonal exchanges. Our results highlight ESBL-E. coli dissemination across seabirds of the HCE, including species that unusually forage on human waste like pelicans.

Multidrug-resistant Escherichia coli isolated from free-range chickens in the Caatinga biome.

Antimicrobial-resistant Escherichia coli is a global health challenge from a One Health perspective. However, data on its emergence in the Caatinga biome are limited. This biome is exclusive to the Brazilian Northeast and offers unique epidemiological conditions that can influence the occurrence of infectious diseases and antimicrobial resistance. In this study, the carriage proportion, antimicrobial susceptibility, and population structure of cephalosporin-resistant E. coli were assessed in 300 cloacal swab samples of free-range chickens from three Brazilian states covered by the Caatinga biome. The results showed that 44 (14.7%) samples were positive for cephalosporin-resistant E. coli, and Paraíba state had the highest frequency of isolates (68.2%). Genes encoding cephotaximase-Munich or ampicillin class C (AmpC) enzymes were identified in 30 (68.2%) and 8 (18.2%) isolates, respectively, comprising 31 E. coli isolates. Overall, molecular typing by genome restriction using XbaI endonuclease followed by pulsed-field gel electrophoresis revealed four clusters from two properties of Paraíba state composed by extended-spectrum ß-lactamase-producing and AmpC-producing E. coli carrying blaCTX-M-1-like and blaMIR-1/ACT-1 genes and belonging to different phylogenetic groups. There is a need to control antimicrobial resistance while taking into account the genetic diversity of the strains and their implications for animal and public health, especially in free-range chickens reared in the Brazilian Caatinga biome.

Detection of pathogenic, heteropathogenic and hybrid Escherichia coli strains in psittacines from zoos and breeders in the state of Ceará, Brazil.

The current study aimed to detect virulence, hetero-pathogenicity, and hybridization genes in Escherichia coli strains, previously isolated from cloacal swabs in commercial breeding psittacines and zoological collections, via multiplex PCR. A total of 68 strains of E. coli, previously isolated from psittacines in zoos and commercial breeding facilities in Ceará, Brazil, were assessed for the presence of the following genes and/or probes: eae, bfpA (EPEC - Enteropathogenic E. coli), CVD432 (EAEC - Enteroaggregative E. coli); LT gene and ST gene (ETEC - Enterotoxigenic E. coli); ipaH (EIEC - Enteroinvasive E. coli); stx1 and stx2 (STEC - Shiga toxin-producing E. coli); iroN, ompT, hlyF, iss, and iutA (APEC - Avian pathogenic E. coli). Of the 68 E. coli strains analyzed, 61 (98.7 %) were positive for the following genes and/or probes: Stx1 (61/98.7 %), ST gene (54/79.4 %), CVD432 (49/72 %), bfpA (44/64.7 %), eae (42/61.8 %), Stx2 (41/60.3 %), ipaH (34/50 %), LT gene (33/48.5 %), iroN (21/30.9 %), hlyF (11/6.2 %), iss (06/8.8 %) and iutA (06/8.8 %). The following diarrheagenic pathotypes were identified: 66 (97 %) from STEC, 49 (72 %) from EAEC, 35 (52 %) from EIEC, 25 (37 %) from ETEC, and one (1.5 %) from EPEC. Regarding hetero-pathogenicity, 50 (74 %) heterogeneous strains were identified. Positivity for APEC was seen in four (6 %) strains, all characterized as pathogenic hybrids. This study describes significant associations of virulence factors in E. coli strains DEC/DEC and DEC/APEC, which were isolated from psittacines and may be potentially harmful to One Health.

Gut colonization by extended-spectrum ß-lactamase-producing Escherichia coli in dairy herd in Brazil: successful dissemination of a One Health clone.

The overuse of antimicrobials in livestock has contributed to the emergence and selection of clinically relevant multidrug-resistant bacteria. In Brazil, there is no conclusive information on the occurrence of Escherichia coli producing extended-spectrum ß-lactamase (ESßL) in cattle breeding, which is an important sector of agribusiness in this country. Herein, we investigated the presence of ESßL-positive E. coli strains in dairy cattle from a commercial farm with routine practice of therapeutic cephalosporins. Ninety-five rectal swab samples were collected from healthy dairy calves and cows under treatment with ceftiofur. Samples were screened for the presence of ESßL producers, and positive isolates were identified by MALDI-TOF, with subsequent screening for genes encoding ESßL variants by PCR and sequencing. The presence of ESßL (CTX-M-15)-producing E. coli was confirmed in calves, and lactating and dry cows. Most ESßL strains with genetic homologies ≥ 90% were grouped into two major PFGE clusters, confirming the suscessful expansion of clonally related lineages in animals from different lactating cycles, on the same property. Four representatives CTX-M-15-positive E. coli strains had their genomes sequenced, belonging to the clonal complex (CC) 23 and sequence type (ST) 90. A phylogeographical landscape of ST90 was performed revealing a global One Health linkage. Our results highlight the intestinal microbiota of dairy cattle as a hotspot for the spread of critical priority ESßL-producing E. coli and demonstrate that ST90 is an international clone genomically adapted to human and animal hosts, which deserve additional investigation to determine its zoonotic potential and impact in food chain.

Characterization of antimicrobial resistance profiles in Escherichia coli isolated from captive mammals in Ecuador.

BACKGROUND: This study focuses on the AMR profiles in E. coli isolated from captive mammals at EcoZoo San Martín, Baños de Agua Santa, Ecuador, highlighting the role of wildlife as reservoirs of resistant bacteria. AIMS: The aim of this research is to investigate the antimicrobial resistance profiles of E. coli strains isolated from various species of captive mammals, emphasizing the potential zoonotic risks and the necessity for integrated AMR management strategies. MATERIALS & METHODS: A total of 189 fecal samples were collected from 70 mammals across 27 species. These samples were screened for E. coli, resulting in 90 identified strains. The resistance profiles of these strains to 16 antibiotics, including 10 ß-lactams and 6 non-ß-lactams, were determined using the disk diffusion method. Additionally, the presence of Extended-Spectrum Beta-Lactamase (ESBL) genes and other resistance genes was analyzed using PCR. RESULTS: Significant resistance was observed, with 52.22% of isolates resistant to ampicillin, 42.22% to ceftriaxone and cefuroxime, and 27.78% identified as ESBL-producing E. coli. Multiresistance (resistance to more than three antibiotic groups) was found in 35.56% of isolates. Carnivorous and omnivorous animals, particularly those with prior antibiotic treatments, were more likely to harbor resistant strains. DISCUSSION: These findings underscore the role of captive mammals as indicators of environmental AMR. The high prevalence of resistant E. coli in these animals suggests that zoos could be significant reservoirs for the spread of antibiotic-resistant bacteria. The results align with other studies showing that diet and antibiotic treatment history influence resistance profiles. CONCLUSION: The study highlights the need for an integrated approach involving veterinary care, habitat management, and public awareness to prevent captive wildlife from becoming reservoirs of antibiotic-resistant bacteria. Improved waste management practices and responsible antibiotic use are crucial to mitigate the risks of AMR in zoo environments and reduce zoonotic threats.

Galleria mellonella larvae as an alternative model to determine the pathogenicity of avian pathogenic Escherichia coli.

RESEARCH HIGHLIGHTS: Galleria mellonella larvae are a viable model for determining APEC pathogenicity.Larval disease score is the main variable for determining APEC pathogenicity.Response variables should be evaluated up to 24 h post-inoculation.

Unveiling the traits of antibiotic resistance and virulence in Escherichia coli obtained from poultry waste.

Antibiotic resistance and virulence factors in avian pathogenic Escherichia coli (APEC) have become significant concerns, contributing to adverse environmental effects. The extensive use of antibiotics in poultry farming has resulted in the emergence of antibiotic-resistant APEC strains. This study prioritizes the molecular screening of APEC to uncover their antibiotic resistance and virulence attributes, with specific attention to their environmental impact. To address the imperative of understanding APEC pathogenesis, our study analyzed 50 poultry waste samples including 10 poultry litter, 15 fecal matter, 15 wastewater, and 10 anatomical waste samples. For the presence of virulence genes, 35 Escherichia coli isolates were subjected to molecular characterization. Amongst these, 27 were APEC strains demonstrating the presence of at least four virulence genes each. Notably, virulence genes such as fimH, ompA, ybjX, waaL, cvaC, hlyF, iss, ompT, and iroN were observed among all the E. coli isolates. Furthermore, eleven of the APEC strains exhibited resistance to tetracycline, ampicillin, sulphonamides, and fluoroquinolones.These findings highlight the role of APEC as a potential source of environmental pollution serving as a reservoir for virulence and resistance genes. Understanding the dynamics of antibiotic resistance and virulence in APEC is essential due to its potential threat to broiler chickens and the broader population through the food chain, intensifying concerns related to environmental pollution. Recognizing the ecological impact of APEC is essential for developing effective strategies to mitigate environmental pollution and safeguard the health of ecosystems and human populations.

Effects of dietary yeast mannan-rich fraction supplementation on growth performance, intestinal morphology, and lymphoid tissue characteristics in weaned piglets challenged with Escherichia Coli F4.

We evaluated the effects of supplementing yeast mannan-reach-fraction on growth performance, jejunal morphology and lymphoid tissue characteristics in weaned piglets challenged with E. Coli F4. A total of 20 crossbred piglets were used. At weaning, piglets were assigned at random to one of four groups: piglets challenged and fed the basal diet supplemented with yeast mannan-rich fraction (C-MRF, n = 5); piglets challenged and fed the basal diet (C-BD, n = 5); piglets not challenged and fed the basal diet supplemented with yeast mannan-rich fraction (NC-MRF, n = 5), and piglets not challenged and fed the basal diet (NC-BD). Each dietary treatment had five replicates. On days 4, 5 and 10, piglets were orally challenged with 108 CFU/mL of E. Coli F4. C-MRF piglets had higher BW (p = 0.002; interactive effect) than C-BD piglets. C-MRF piglets had higher (p = 0.02; interactive effect) ADG in comparison with C-BD piglets. C-MRF piglets had higher (p = 0.04; interactive effect) ADFI than C-BD piglets. The diameter of lymphoid follicles was larger (p = 0.010; interactive effect) in the tonsils of C-MRF piglets than C-BD piglets. Lymphoid cells proliferation was greater in the mesenteric lymphnodes and ileum (p = 0.04 and p = 0.03, respectively) of C-MRF piglets. A reduction (p > 0.05) in E. Coli adherence in the ileum of piglets fed MRF was observed. In conclusion, the results of the present study demonstrate that dietary yeast mannan-rich fraction supplementation was effective in protecting weaned piglets against E. Coli F4 challenge.

Escherichia coli isolated from pyometra and cystitis in the same animal exhibit a wide phenotypic similarity.

AIMS: Pyometra and cystitis caused by Escherichia coli are common diseases identified in canine or feline females. The origin of pyometra infection remains uncertain, and effective prevention strategies for this disease are still unknown. This study aimed to provide a phenotypic characterization, including antimicrobial resistance and virulence profiles, of endometrial pathogenic (EnPEC) and uropathogenic (UPEC) E. coli strains isolated simultaneously from the same animal. METHODS AND RESULTS: Sixteen E. coli strains, from eight different animals, were analyzed in this study. The antimicrobial susceptibility profile of EnPEC and UPEC strains was determined using the disc diffusion method, which showed a similar susceptibility profile among strains (EnPEC and UPEC) from the same animal. The virulence profile of the strains was assessed through biofilm formation, as well as serum resistance abilities. EnPEC and UPEC strains from the same animal exhibited slight variations in their virulence and antimicrobial resistance capabilities. Overall, most of the strain pairs showed a high similarity in their ability to establish biofilms and survive in serum complement activity. CONCLUSIONS: Overall, strains of E. coli isolated from both pyometra and cystitis in the same animal, despite presenting distinct clinical diseases, exhibit a wide phenotypic similarity, suggesting a common origin for the strains.

Multidrug-resistant phenotypes of genetically diverse Escherichia coli isolates from healthy domestic cats.

Β-lactamases-producing Escherichia coli are a widely distributed source of antimicrobial resistance (AMR), for animals and humans. Little is known about the sensitivity profile and genetic characteristics of E. coli strains isolated from domestic cats. We report a cross-sectional study that evaluated E. coli strains isolated from domestic cats in Panama. For this study the following antibiotics were analyzed: ampicillin, amoxicillin-clavulanate cefepime, cefotaxime, cefoxitin, ceftazidime, aztreonam, imipenem, gentamicin, kanamycin, streptomycin, tetracycline, ciprofloxacin, nalidixic acid, trimethoprim-sulfamethoxazole, and chloramphenicol. The data obtained were classified as resistant, intermediate, or sensitive. MDR strains were established when the strain presented resistance to at least one antibiotic from three or more antimicrobial classes. Forty-eight E. coli isolates were obtained, of which 80% presented resistance to at least one of the antibiotics analyzed, while only 20% were sensitive to all (p = 0.0001). The most common resistance was to gentamicin (58%). Twenty-nine percent were identified as multidrug-resistant isolates and 4% with extended spectrum beta-lactamase phenotype. The genes blaTEM (39%), blaMOX(16%), blaACC (16%) and blaEBC (8%) were detected. Plasmid-mediated resistance qnrB (25%) and qnrA (13%) are reported. The most frequent sequence types (STs) being ST399 and we reported 5 new STs. Our results suggest that in intestinal strains of E. coli isolated from domestic cats there is a high frequency of AMR.

High frequency of multidrug-resistant Escherichia coli from cattle in the Cerrado and Pantanal biomes of Brazil.

The indiscriminate use of antimicrobials has led to the emergence of resistant bacteria, especially pathogenic strains of Escherichia coli, which are associated with diseases in animals and humans. The aim of the present study was to characterize E. coli isolates in calves with regards to the presence of virulence genes and investigate the resistance of the isolates to different antimicrobials. Between 2021 and 2023, 456 fecal samples were collected from calves in the Pantanal and Cerrado biomes of the state of Mato Grosso do Sul, Brazil. All samples were subjected to microbiological analysis and disc diffusion antibiogram testing. The polymerase chain reaction method was used to detect virulence genes. Bacterial growth was found in 451 of the 456 samples and biochemically identified as Escherichia coli. All 451 isolates (100 %) exhibited some phenotypic resistance to antimicrobials and 67.62 % exhibited multidrug resistance. The frequency of multidrug-resistant isolates in the Cerrado biome was significantly higher than that in the Pantanal biome (p = 0.0001). In the Cerrado, the most common pathotype was Shiga toxin-producing Escherichia coli (STEC) (28 %), followed by toxigenic Escherichia coli (ETEC) (11 %), enterohemorrhagic Escherichia coli (EHEC) (8 %) and enteropathogenic Escherichia coli (EPEC) (2 %). In most cases, the concomitant occurrence of pathotypes was more common, the most frequent of which were ETEC + STEC (33 %), ETEC + EHEC (15 %) and ETEC + EPEC (3 %). The STEC pathotype (30 %) was also found more frequently in the Pantanal, followed by EHEC (12 %), ETEC (9 %) and EPEC (6 %). The STEC pathotype had a significantly higher frequency of multidrug resistance (p = 0.0486) compared to the other pathotypes identified. The frequency of resistance was lower in strains from the Pantanal biome compared to those from the Cerrado biome. Although some factors are discussed in this paper, it is necessary to clarify the reasons for this difference and the possible impacts of these findings on both animal and human health in the region.

Prevalence, antimicrobial resistance and detection of virulence genes of Escherichia coli and Salmonella spp. isolated from white-lipped peccaries and collared peccaries.

Salmonella spp. and Escherichia coli are implicated in human and animal infections and require antimicrobial treatment in many situations. Faecal samples of healthy white-lipped peccaries (Pecari tajacu) (n = 30) and collared peccaries (Tayassu pecari ) (n = 60) obtained in three farms located in the Midwest Brazil. The antimicrobial profiles of commensal E. coli from P. tajacu and T. pecari from commercial herds in Brazil were isolated and analyzed and virulence genes were detected. Among 90 healthy animals, no Salmonella spp. were isolated. However, 30 samples (27%) tested positive for E. coli, with 18 isolates from P. tajacu and 12 from T. pecari, representing frequencies of 58.0% and 38.7%, respectively. Additionally, other Enterobacteriaceae family bacteria were detected but not included in this analysis. However, individual samples from 30 animals tested positive for E. coli, of which 16 were isolated from P. tajacu presenting multidrug resistance and six were isolated from T. pecari presenting a similar pattern. The E. coli virulence genes detected were papC (pilus-associated pyelonephritis) in five isolates, tsh (temperature-sensitive hemagglutinin) in one isolate, and eae (enteric attachment and effacement) in one isolate. The serum resistance gene, iss (increased serum survival), was detected in four isolates. An association between these genes and the presence of hemolysin was also observed in one isolate. Thus, T. pecari and P. tajacu are potential reservoirs of pathogenic and multidrug-resistant and E. coli. Faecal E. coli of healthy P. tajacu and T. pecari could act as a possible reservoir of antimicrobial resistance genes in environment.

Characterization of diarrheagenic Escherichia coli from different cattle production systems in Brazil.

Diarrheagenic E. coli (DEC) can cause severe diarrhea and is a public health concern worldwide. Cattle are an important reservoir for this group of pathogens, and once introduced into the abattoir environment, these microorganisms can contaminate consumer products. This study aimed to characterize the distribution of DEC [Shiga toxin-producing E. coli (STEC), enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), and enteroaggregative E. coli (EAEC)] from extensive and intensive cattle production systems in Brazil. Samples (n = 919) were collected from animal feces (n = 200), carcasses (n = 600), meat cuts (n = 90), employee feces (n = 9), and slaughterhouse water (n = 20). Virulence genes were detected by PCR in 10% of animal samples (94/919), with STEC (n = 81) as the higher prevalence, followed by EIEC (n = 8), and lastly EPEC (n = 5). Animals raised in an extensive system had a higher prevalence of STEC (average 48%, sd = 2.04) when compared to animals raised in an intensive system (23%, sd = 1.95) (Chi-square test, P < 0.001). From these animals, most STEC isolates only harbored stx2 (58%), and 7% were STEC LEE-positive isolates that were further identified as O157:H7. This study provides further evidence that cattle are potential sources of DEC, especially STEC, and that potentially pathogenic E. coli isolates are widely distributed in feces and carcasses during the slaughter process.

Effects of feeding pasteurized waste milk or saleable milk to calves on weight, health and fecal Escherichia coli antimicrobial resistance.

The aim of this study was to compare the effects of feeding pasteurized waste milk or saleable milk to calves on weight, health and emergence of antimicrobial resistance in Escherichia coli strains isolated from those calves. An experimental study under field conditions on a commercial pasture-based Argentinian dairy farm was carried out. Forty Holstein calves were assigned randomly to either pasteurized waste milk (PWM) or non-pasteurized saleable milk (SM). The antimicrobial agents (AM) used on the farm, both to treat or prevent diseases, were recorded. The passive immunity level, calf live weight, AM presence in milk, clinical examination of calves, and E. coli isolation and identification, were performed. A total of 258 E. coli strains were isolated from fecal samples (132 isolates from SM calves and 126 from PWM calves at six sampling times). All E. coli isolated were used to perform AM susceptibility tests (disc diffusion and agar dilution). No differences were observed between groups in health parameters, average daily gain or prevalence of resistant E. coli strains to any AM evaluated throughout the study. Peaks of trimethoprim, sulfamethoxazole and enrofloxacin minimum inhibitory concentration (MIC) were observed at 30 d in E. coli from both groups of calves, whilst additional peaks to tetracyclin and ampicillin were observed only in SM calves. All MIC apart from gentamicin decreased at 75 and 90 d of age (during the weaning period). Gentamicin MIC behaved differently, having no peaks and increasing at 90 d only in PWM group. In conclusion, we found no evidence that emergence of antibiotic resistance is related to the consumption of pasteurized waste milk.

Antimicrobial efficiency of bromhexine hydrochloride against endometritis-causing Escherichia coli and Trueperella pyogenes in bovines.

In this study, the main agents associated with endometritis in cows in the state of Santa Catarina, Brazil, were identified and the resistance profile and virulence mechanisms of the bacterial isolates were evaluated. Isolates of Escherichia coli and Trueperella pyogenes were tested for their biofilm forming ability and the antimicrobial action of bromhexine hydrochloride in combination with other antimicrobials. A total of 37 uterine lavage samples were collected from cows with endometritis. Of the 55 bacteria isolated, 25.4% were identified as T. pyogenes and 16.3% as E. coli. The bacterial isolates showed greater resistance to sulfamethoxazole + trimethoprim (58.2%) and tetracycline (56.3%). Among the species, E. coli showed the highest resistance rates, with 100% of isolates showing resistance to amoxicillin, streptomycin, and gentamicin. The results of the minimum inhibitory concentration for the T. pyogenes isolates showed that 91.6% of the isolates were resistant to enrofloxacin and tetracycline, and 75% were resistant to ceftiofur and sulfamethoxazole + trimethoprim. All E. coli and T. pyogenes isolates showed biofilm forming ability. The plo, fimA, and nanH genes were identified in 100% of T. pyogenes isolates. In parallel, 100% of E. coli isolates had the fimH gene, and 11.1% had the csgD gene. Bromhexine hydrochloride showed antimicrobial activity against 100% of E. coli isolates and 66.6% of T. pyogenes isolates. Furthermore, when associated with antimicrobials, bromhexine hydrochloride has a synergistic and additive effect, proving to be an option in the treatment of endometritis in cows and an alternative for reducing the use of antimicrobials.

Carrier state of enterotoxigenic Escherichia coli virulence markers in pigs: Effects on gut microbiota modulation and immune markers transcription.

Enterotoxigenic Escherichia coli (ETEC) causes diarrhea in pigs at early age, leading to high mortality rates and significant economic losses in the swine industry. ETEC effect on gut microbiota and immune system is mostly studied in diarrheic model under controlled laboratory conditions, however its impact on asymptomatic carriers remains unknown. Thus, we investigated whether ETEC can modulate gut microbiota or regulate the transcription of immune markers in asymptomatic pigs in farm environment. Stool samples from newborn piglets, nursery and growing pigs, and sows were screened for ETEC markers, then submitted to 16S-rDNA sequencing to explore gut microbiota composition in carriers (ETEC+) and non-carriers (ETEC-) animals. We observed a reduced α-diversity in ETEC+ animals (p < 0.05), while bacterial compositions were mostly driven by ageing (p > 0.05). Prevotella marked ETEC-carrier group, while Rikenellaceae RC9 gut group was a marker for a healthy gut microbiota, suggesting that they might be biomarker candidates for surveillance and supplementation purposes. Furthermore, we observed transcription regulation of il6 and tff2 genes in ETEC+ in newborn and nursery stages, respectively. Our findings indicate that ETEC presence modulate gut microbiota and the immune response in asymptomatic pigs; nevertheless, further studies using a probabilistic design must be performed to assess the effect of ETEC presence on gut imbalance in pigs despite the age bias.

Resistant Escherichia coli isolated from wild mammals from two rescue and rehabilitation centers in Costa Rica: characterization and public health relevance.

This study aimed to characterize the antimicrobial resistance (AMR) and virulence profiles of 67 Escherichia coli isolates obtained from faecal samples of 77 wild mammals from 19 different species, admitted in two rescue and rehabilitation centers in Costa Rica. It was possible to classify 48% (n = 32) of the isolates as multidrug-resistant, and while the highest resistance levels were found towards commonly prescribed antimicrobials, resistance to fluoroquinolones and third generation cephalosporins were also observed. Isolates obtained from samples of rehabilitated animals or animals treated with antibiotics were found to have significantly higher AMR levels, with the former also having a significant association with a multidrug-resistance profile. Additionally, the isolates displayed the capacity to produce α-haemolysins (n = 64, 96%), biofilms (n = 51, 76%) and protease (n = 21, 31%). Our results showed that AMR might be a widespread phenomenon within Costa Rican wildlife and that both free-ranging and rehabilitated wild mammals are potential carriers of bacteria with important resistance and virulence profiles. These results highlight the need to study potential sources of resistance determinants to wildlife, and to determine if wild animals can disseminate resistant bacteria in the environment, potentially posing a significant threat to public health and hindering the implementation of a "One Health" approach.

Comparative genetic and pathogenic approaches of Escherichia coli isolated simultaneously from pyometra and urine of bitches.

Escherichia coli (E. coli) are widely related to pyometra and cystitis in dogs, and these infections can occur simultaneously. The goal of this study was to determine genetic and pathogenic insights of 14 E. coli isolated simultaneously from pyometra content and bladder urine of seven bitches. To achieve this, in silico and in vitro comparative analyses were conducted. Whole-genome comparisons demonstrated that E. coli isolated from pyometra and urine of the same animal were predominantly genetic extraintestinal E. coli clones belonging to the same Sequence Type and phylogroup. The E. coli clones identified in this study included ST372, ST457, ST12, ST127, ST646, and ST961. Five isolates (35.7%) belonged to the ST12 complex. Except for two E. coli, all other isolates belonged to the B2 Clermont phylogroup. Interestingly, some genomes of E. coli from urine carried more virulence genes than those E. coli from pyometra. Both pyometra and urine E. coli isolates demonstrated a strong affinity for adhering to HeLa and T24 cells, with a low affinity for invading them. However, certain isolates from urine exhibited a greater tendency to adhere to T24 cells in qualitative and quantitative assays compared to isolates from pyometra. In conclusion, this study revealed the high genomic similarity between pyometra and urine E. coli isolates, as well as the virulent capacity of both to colonize endometrial and urothelial cells. The findings of this study underscore the importance of concurrently managing both infections clinically and could potentially contribute to future resources for the prevention of cystitis and pyometra.