Isolation and Characterization of Potentially Pathogenic Antimicrobial-Resistant Escherichia coli Strains from Chicken and Pig Farms in Spain

ABSTRACT To ascertain whether on animal farms there reside extended-spectrum β-lactamase (ESBL) and plasmidic class C β-lactamase-producing Escherichia coli isolates potentially pathogenic for humans, phylogenetic analyses, pulsed-field gel electrophoresis (PFGE) typing, serotyping, and virulence genotyping were performed for 86 isolates from poultry (57 isolates) and pig (29 isolates) farms. E. coli isolates from poultry farms carried genes encoding enzymes of the CTX-M-9 group as well as CMY-2, whereas those from pig farms mainly carried genes encoding CTX-M-1 enzymes. Poultry and pig isolates differed significantly in their phylogenetic group assignments, with phylogroup A predominating in pig isolates and phylogroup D predominating in avian isolates. Among the 86 farm isolates, 23 (26.7%) carried two or more virulence genes typical of extraintestinal pathogenic E. coli (ExPEC). Of these, 20 were isolated from poultry farms and only 3 from pig farms. Ten of the 23 isolates belonged to the classic human ExPEC serotypes O2:H6, O2:HNM, O2:H7, O15:H1, and O25:H4. Despite the high diversity of serotypes and pulsotypes detected among the 86 farm isolates, 13 PFGE clusters were identified. Four of these clusters contained isolates with two or more virulence genes, and two clusters exhibited the classic human ExPEC serotypes O2:HNM (ST10) and O2:H6 (ST115). Although O2:HNM and O2:H6 isolates of human and animal origins differed with respect to their virulence genes and PFGE pulsotypes, the O2:HNM isolates from pigs showed the same sequence type (ST10) as those from humans. The single avian O15:H1 isolate was compared with human clinical isolates of this serotype. Although all were found to belong to phylogroup D and shared the same virulence gene profile, they differed in their sequence types (ST362-avian and ST393-human) and PFGE pulsotypes. Noteworthy was the detection, for the first time, in poultry farms of the clonal groups O25b:H4-ST131-B2, producing CTX-M-9, and O25a-ST648-D, producing CTX-M-32. The virulence genes and PFGE profiles of these two groups were very similar to those of clinical human isolates. While further studies are required to determine the true zoonotic potential of these clonal groups, our results emphasize the zoonotic risk posed especially by poultry farms, but also by pig farms, as reservoirs of ESBL- and CMY-2-encoding E. coli.

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Prevalence of Avian PathogenicEscherichia coli(APEC) Clone HarboringsfaGene in Brazil

The Scientific World JOURNAL ◽

10.1100/2012/437342 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 20

Author(s):

Terezinha Knöbl ◽

Andrea Micke Moreno ◽

Renata Paixão ◽

Tânia Aparecida Tardelli Gomes ◽

Mônica Aparecida Midolli Vieira ◽

...

Keyword(s):

Escherichia Coli ◽

Polymerase Chain Reaction ◽

Length Polymorphism ◽

Virulence Genes ◽

Fragment Length Polymorphism ◽

Chain Reaction ◽

E Coli ◽

Zoonotic Risk ◽

Poultry Farms ◽

Polymerase Chain

Escherichia coli sfa+ strains isolated from poultry were serotyped and characterized by polymerase chain reaction (PCR) and amplified fragment length polymorphism (AFLP). Isolates collected from 12 Brazilian poultry farms mostly belonged to serogroup O6, followed by serogroups O2, O8, O21, O46, O78, O88, O106, O111, and O143. Virulence genes associated were:iuc90%,fim86%neuS60%,hly34%,tsh28%,crl/csg26%,iss26%,pap18%, and 14%cnf. Strains from the same farm presented more than one genotypic pattern belonging to different profiles in AFLP. AFLP showed a clonal relation betweenEscherichia coli sfa+ serogroup O6. The virulence genes found in these strains reveal some similarity with extraintestinalE. coli(ExPEC), thus alerting for potential zoonotic risk.

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

World Rabbit Science ◽

10.4995/wrs.2020.10879 ◽

2020 ◽

Vol 28 (2) ◽

pp. 81

Author(s):

Raouia Ben Rhouma ◽

Ahlem Jouini ◽

Amira Klibi ◽

Safa Hamrouni ◽

Aziza Boubaker ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Virulence Genes ◽

Antimicrobial Agents ◽

Antibiotic Resistance Genes ◽

Virulence Gene ◽

Diffusion Method ◽

Class 1 Integron ◽

E Coli ◽

Class 1

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

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Intestine and Environment of the Chicken as Reservoirs for Extraintestinal Pathogenic Escherichia coli Strains with Zoonotic Potential

Applied and Environmental Microbiology ◽

10.1128/aem.01324-08 ◽

2008 ◽

Vol 75 (1) ◽

pp. 184-192 ◽

Cited By ~ 133

Author(s):

Christa Ewers ◽

Esther-Maria Antï¿½o ◽

Ines Diehl ◽

Hans-C. Philipp ◽

Lothar H. Wieler

Keyword(s):

Escherichia Coli ◽

Virulence Gene ◽

Infection Model ◽

E Coli ◽

Gene Profiles ◽

Pathogenic Escherichia Coli ◽

Zoonotic Risk ◽

Resistant Strains ◽

Genetic Pool

ABSTRACT Although research has increasingly focused on the pathogenesis of avian pathogenic Escherichia coli (APEC) infections and the “APEC pathotype” itself, little is known about the reservoirs of these bacteria. We therefore compared outbreak strains isolated from diseased chickens (n = 121) with nonoutbreak strains, including fecal E. coli strains from clinically healthy chickens (n = 211) and strains from their environment (n = 35) by determining their virulence gene profiles, phylogenetic backgrounds, responses to chicken serum, and in vivo pathogenicities in a chicken infection model. In general, by examining 46 different virulence-associated genes we were able to distinguish the three groups of avian strains, but some specific fecal and environmental isolates had a virulence gene profile that was indistinguishable from that determined for outbreak strains. In addition, a substantial number of phylogenetic EcoR group B2 strains, which are known to include potent human and animal extraintestinal pathogenic E. coli (ExPEC) strains, were identified among the APEC strains (44.5%) as well as among the fecal E. coli strains from clinically healthy chickens (23.2%). Comparably high percentages (79.2 to 89.3%) of serum-resistant strains were identified for all three groups of strains tested, bringing into question the usefulness of this phenotype as a principal marker for extraintestinal virulence. Intratracheal infection of 5-week-old chickens corroborated the pathogenicity of a number of nonoutbreak strains. Multilocus sequence typing data revealed that most strains that were virulent in chicken infection experiments belonged to sequence types that are almost exclusively associated with extraintestinal diseases not only in birds but also in humans, like septicemia, urinary tract infection, and newborn meningitis, supporting the hypothesis that not the ecohabitat but the phylogeny of E. coli strains determines virulence. These data provide strong evidence for an avian intestinal reservoir hypothesis which could be used to develop intestinal intervention strategies. These strains pose a zoonotic risk because either they could be transferred directly from birds to humans or they could serve as a genetic pool for ExPEC strains.

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Recent Emergence of Clonal Group O25b:K1:H4-B2-ST131 ibeA Strains among Escherichia coli Poultry Isolates, Including CTX-M-9-Producing Strains, and Comparison with Clinical Human Isolates

Applied and Environmental Microbiology ◽

10.1128/aem.01112-10 ◽

2010 ◽

Vol 76 (21) ◽

pp. 6991-6997 ◽

Cited By ~ 66

Author(s):

Azucena Mora ◽

Alexandra Herrera ◽

Rosalia Mamani ◽

Cecilia López ◽

María Pilar Alonso ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Gene ◽

Clonal Group ◽

E Coli ◽

Strain Collection ◽

Zoonotic Risk ◽

Recent Emergence ◽

Avian Origin ◽

K1 Capsule ◽

M 14

ABSTRACT To discern the possible spread of the Escherichia coli O25b:H4-ST131 clonal group in poultry and the zoonotic potential of avian strains, we made a retrospective search of our strain collection and compared the findings for those strains with the findings for current strains. Thus, we have characterized a collection of 19 avian O25b:H4-ST131 E. coli strains isolated from 1995 to 2010 which, interestingly, harbored the ibeA gene. Using this virulence gene as a criterion for selection, we compared those 19 avian strains with 33 human O25b:H4-ST131 ibeA-positive E. coli strains obtained from patients with extraintestinal infections (1993 to 2009). All 52 O25b:H4-ST131 ibeA-positive E. coli strains shared the fimH, kpsMII, malX, and usp genes but showed statistically significant differences in nine virulence factors, namely, papGIII, cdtB, sat, and kpsMII K5, which were associated with human strains, and iroN, kpsMII K1, cvaC, iss, and tsh, which were associated with strains of avian origin. The XbaI macrorestriction profiles of the 52 E. coli O25b:H4-ST131 ibeA-positive strains revealed 11 clusters (clusters I to XI) of >85% similarity, with four clusters including strains of human and avian origin. Cluster VII (90.9% similarity) grouped 10 strains (7 avian and 3 human strains) that mostly produced CTX-M-9 and that also shared the same virulence profile. Finally, we compared the macrorestriction profiles of the 12 CTX-M-9-producing O25b:H4-ST131 ibeA strains (7 avian and 5 human strains) identified among the 52 strains with those of 15 human O25b:H4-ST131 CTX-M-14-, CTX-M-15-, and CTX-M-32-producing strains that proved to be negative for ibeA and showed that they clearly differed in the level of similarity from the CTX-M-9-producing strains. In conclusion, E. coli clonal group O25b:H4-ST131 ibeA has recently emerged among avian isolates with the new acquisition of the K1 capsule antigen and includes CTX-M-9-producing strains. This clonal group represents a real zoonotic risk that has crossed the barrier between human and avian hosts.

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Reconstitution of Acetosyringone-Mediated Agrobacterium tumefaciens Virulence Gene Expression in the Heterologous Host Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.183.12.3704-3711.2001 ◽

2001 ◽

Vol 183 (12) ◽

pp. 3704-3711 ◽

Cited By ~ 23

Author(s):

Scott M. Lohrke ◽

Hongjiang Yang ◽

Shouguang Jin

Keyword(s):

Gene Expression ◽

Escherichia Coli ◽

Agrobacterium Tumefaciens ◽

Virulence Genes ◽

Virulence Gene ◽

Dependent Manner ◽

Gene Encoding ◽

Virulence Gene Expression ◽

E Coli ◽

Glucose Binding

ABSTRACT The ability to utilize Escherichia coli as a heterologous system in which to study the regulation ofAgrobacterium tumefaciens virulence genes and the mechanism of transfer DNA (T-DNA) transfer would provide an important tool to our understanding and manipulation of these processes. We have previously reported that the rpoA gene encoding the alpha subunit of RNA polymerase is required for the expression of lacZ gene under the control of virB promoter (virBp::lacZ) in E. colicontaining a constitutively active virG gene [virG(Con)]. Here we show that an RpoA hybrid containing the N-terminal 247 residues from E. coli and the C-terminal 89 residues from A. tumefaciens was able to significantly express virBp::lacZ in E. coli in a VirG(Con)-dependent manner. Utilization oflac promoter-driven virA and virGin combination with the A. tumefaciens rpoA construct resulted in significant inducer-mediated expression of thevirBp::lacZ fusion, and the level ofvirBp::lacZ expression was positively correlated to the copy number of the rpoA construct. This expression was dependent on VirA, VirG, temperature, and, to a lesser extent, pH, which is similar to what is observed in A. tumefaciens. Furthermore, the effect of sugars on virgene expression was observed only in the presence of thechvE gene, suggesting that the glucose-binding protein ofE. coli, a homologue of ChvE, does not interact with the VirA molecule. We also evaluated other phenolic compounds in induction assays and observed significant expression with syringealdehyde, a low level of expression with acetovanillone, and no expression with hydroxyacetophenone, similar to what occurs in A. tumefaciens strain A348 from which the virA clone was derived. These data support the notion that VirA directly senses the phenolic inducer. However, the overall level of expression of thevir genes in E. coli is less than what is observed in A. tumefaciens, suggesting that additional gene(s) from A. tumefaciens may be required for the full expression of virulence genes in E. coli.

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Virulence Genes and Molecular Typing of Different Groups of Escherichia coli O157 Strains in Cattle

Applied and Environmental Microbiology ◽

10.1128/aem.00873-09 ◽

2009 ◽

Vol 75 (19) ◽

pp. 6282-6291 ◽

Cited By ~ 31

Author(s):

István Tóth ◽

Herbert Schmidt ◽

Gábor Kardos ◽

Zsuzsanna Lancz ◽

Kristina Creuzburg ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Genes ◽

Housekeeping Genes ◽

Enzyme Analysis ◽

Virulence Plasmid ◽

O157 Strain ◽

Pathogenic Potential ◽

E Coli ◽

Strain Collection ◽

Genes Encoding

ABSTRACT Characterization of an Escherichia coli O157 strain collection (n = 42) derived from healthy Hungarian cattle revealed the existence of diverse pathotypes. Enteropathogenic E. coli (EPEC; eae positive) appeared to be the most frequent pathotype (n = 22 strains), 11 O157 strains were typical enterohemorrhagic E. coli (EHEC; stx and eae positive), and 9 O157 strains were atypical, with none of the key stx and eae virulence genes detected. EHEC and EPEC O157 strains all carried eae-gamma, tir-gamma, tccP, and paa. Other virulence genes located on the pO157 virulence plasmid and different O islands (O island 43 [OI-43] and OI-122), as well as espJ and espM, also characterized the EPEC and EHEC O157 strains with similar frequencies. However, none of these virulence genes were detected by PCR in atypical O157 strains. Interestingly, five of nine atypical O157 strains produced cytolethal distending toxin V (CDT-V) and carried genes encoding long polar fimbriae. Macro-restriction fragment enzyme analysis (pulsed-field gel electrophoresis) revealed that these E. coli O157 strains belong to four main clusters. Multilocus sequence typing analysis revealed that five housekeeping genes were identical in EHEC and EPEC O157 strains but were different in the atypical O157 strains. These results suggest that the Hungarian bovine E. coli O157 strains represent at least two main clones: EHEC/EPEC O157:H7/NM (nonmotile) and atypical CDT-V-producing O157 strains with H antigens different from H7. The CDT-V-producing O157 strains represent a novel genogroup. The pathogenic potential of these strains remains to be elucidated.

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Virulence factors analysis and antibiotic resistance of uropathogenic Escherichia coli isolated from patients in northeast of Iran

Iranian Journal of Microbiology ◽

10.18502/ijm.v12i3.3240 ◽

2020 ◽

Author(s):

Mahdis Ghavidel ◽

Tahere Gholamhosseini-Moghadam ◽

Kimiya Nourian ◽

Kiarash Ghazvini

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Virulence Genes ◽

High Rate ◽

Resistance Pattern ◽

Antibiotics Resistance ◽

Disk Diffusion Test ◽

E Coli ◽

Genes Encoding ◽

Tract Infections

Background and Objectives: Escherichia coli is known to be the pathogen commonly isolated from those infected with uri- nary tract infections (UTIs). The aim of this study was to investigate the presence of E. coli virulence genes and antibiotics’ resistance pattern among clinical isolates in the Northeast of Iran. Relationships between virulence genes and antimicrobial resistances were studied as well. Materials and Methods: Three hundred isolates of E. coli were isolated from patients with UTIs that referred to Ghaem and Imam Reza hospitals (Mashhad, Iran) during August 2016 to February 2017. A multiplex PCR was employed to amplify the genes encoding pyelonephritis associated pili (pap), S-family adhesions (sfa), type1fimbriae (fimH) and aerobactin (aer). Disk diffusion test was performed to test the susceptibility of isolates to β-lactams, aminoglycosides, cephalosporins, quino- lone, fluoroquinolones, carbapenems and trimethoprim-sulfamethoxazole. Results: The PCR results identified the fimH in 78.4%, aer in 70.5%, sfa in 13.6% and the pap in 8.2% of isolates. The rates of antibiotic resistance of the isolates were as follows: 64.7% resistant to cephalosporins, 34% to trimethoprim-sul- famethoxazole, 31% to fluoroquinolones, 15.3% to aminoglycosides, 13.3% to β-lactams, 7.8% to quinolones and 4.4% to carbapenems. Significant relationships existed between pap and aer, pap and sfa, aer and fluoroquinolones also pap and cephalosporins. Conclusion: fimH and aer were found in > 50% of isolates suggesting the importance of both genes in UPEC. The majority of isolates had fimH as adhesion factor for colonization. Determining antibiotic resistance patterns in specific geographical areas is necessary for appropriate treatment of urinary tract infection. The high rate of resistance to cephalosporins is most likely due to incorrect drug administration

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Virulence gene profiles of avian pathogenic Escherichia coli isolated from chickens with colibacillosis in Bulawayo, Zimbabwe

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v82i1.850 ◽

2015 ◽

Vol 82 (1) ◽

Cited By ~ 10

Author(s):

Joshua Mbanga ◽

Yvonne O. Nyararai

Keyword(s):

Escherichia Coli ◽

Virulence Genes ◽

Virulence Gene ◽

Economic Losses ◽

Avian Pathogenic Escherichia Coli ◽

Pcr Assay ◽

E Coli ◽

Gene Profiles ◽

Pathogenic Escherichia Coli ◽

Polymerase Chain

Colibacillosis, a disease caused by avian pathogenic Escherichia coli (APEC), is one of the main causes of economic losses in the poultry industry worldwide. This study was carried out in order to determine the APEC-associated virulence genes contained by E. coli isolates causing colibacillosis in chickens. A total of 45 E. coli isolates were obtained from the diagnostics and research branch of the Central Veterinary Laboratories, Bulawayo, Zimbabwe. These isolates were obtained from chickens with confirmed cases of colibacillosis after postmortem examination. The presence of the iutA, hlyF, ompT, frz, sitD, fimH, kpsM, sitA, sopB, uvrY, pstB and vat genes were investigated by multiplex polymerase chain reaction (PCR) assay. Of the 45 isolates, 93% were positive for the presence of at least one virulence gene. The three most prevalent virulence genes were iutA (80%), fimH (33.3%) and hlyF (24.4%). The kpsM, pstB and ompT genes had the lowest prevalence, having been detected in only 2.2% of the isolates. All 12 virulence genes studied were detected in the 45 APEC isolates. Virulence gene profiles were constructed for each APEC isolate from the multiplex data. The APEC isolates were profiled as 62.2% fitting profile A, 31.1% profile B and 6.7% profile C. None of the isolates had more than seven virulence genes. Virulence profiles of Zimbabwean APEC isolates are different from those previously reported. Zimbabwean APEC isolates appear to be less pathogenic and may rely on environmental factors and stress in hosts to establish infection.

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Isolation and Characterization of Shiga Toxin–Producing Escherichia coli Serogroups O26, O45, O103, O111, O113, O121, O145, and O157 Shed from Range and Feedlot Cattle from Postweaning to Slaughter

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-373 ◽

2014 ◽

Vol 77 (7) ◽

pp. 1052-1061 ◽

Cited By ~ 18

Author(s):

ABEL B. EKIRI ◽

DOUGLAS LANDBLOM ◽

DAWN DOETKOTT ◽

SUSAN OLET ◽

WEILIN L. SHELVER ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Virulence Genes ◽

Beef Cows ◽

Laboratory Culture ◽

Feedlot Cattle ◽

Fecal Shedding ◽

E Coli ◽

Isolation And Characterization ◽

Inspection Service

Cattle are the main reservoirs for Shiga toxin–producing Escherichia coli (STEC) strains. E. coli O26, O45, O103, O111, O121, O145, and O157 are among the STEC serogroups that cause severe foodborne illness and have been declared as adulterants by the U.S. Department of Agriculture, Food Safety and Inspection Service. The objectives of this study were (i) to estimate the prevalence of non-O157 STEC and E. coli O157 in naturally infected beef cows and in steer calves at postweaning, during finishing, and at slaughter and (ii) to test non-O157 STEC isolates for the presence of virulence genes stx1, stx2, eaeA, and ehlyA. Samples were collected from study animals during multiple sampling periods and included fecal grabs, rectal swabs, and midline sponge samples. Laboratory culture, PCR, and multiplex PCR were performed to recover and identify E. coli and the virulence genes. The prevalence of non-O157 STEC (serogroups O26, O45, O103, O111, O121, O113, and O145) fecal shedding ranged from 8% (4 of 48 samples) to 39% (15 of 38 samples) in cows and 2% (1 of 47 samples) to 38% (9 of 24 samples) in steer calves. The prevalence of E. coli O157 fecal shedding ranged from 0% (0 of 38 samples) to 52% (25 of 48 samples) in cows and 2% (1 of 47 samples) to 31% (15 of 48 samples) in steer calves. In steer calves, the prevalence of non-O157 STEC and E. coli O157 was highest at postweaning, at 16% (15 of 96 samples) and 23% (22 of 96 samples), respectively. Among the 208 non-O157 STEC isolates, 79% (164 isolates) had stx1, 79% (165 isolates) had stx2, and 58% (121 isolates) had both stx1 and stx2 genes. The percentage of non-O157 STEC isolates encoding the eaeA gene was low; of the 165 isolates tested, 8 (5%) were positive for eaeA and 135 (82%) were positive for ehlyA. Findings from this study provide further evidence of non-O157 STEC shedding in beef cows and steer calves particularly at the stage of postweaning and before entry into the feedlot.

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Virulence and antibiotic resistance profile of avian Escherichia coli strains isolated from colibacillosis lesions in central of Algeria

Veterinary World ◽

10.14202/vetworld.2019.1840-1848 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1840-1848 ◽

Cited By ~ 2

Author(s):

Nacima Meguenni ◽

Nathalie Chanteloup ◽

Angelina Tourtereau ◽

Chafika Ali Ahmed ◽

Saliha Bounar-Kechih ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Virulence Factors ◽

Virulence Genes ◽

Iron Acquisition ◽

Virulence Gene ◽

Resistance Profile ◽

E Coli ◽

Antibiotic Resistance Profile ◽

Embryo Lethality

Background and Aim: Avian pathogenic Escherichia coli cause extensive mortality in poultry flocks, leading to extensive economic losses. To date, in Algeria, little information has been available on virulence potential and antibiotics resistance of avian E. coli isolates. Therefore, the aim of this study was the characterization of virulence genes and antibiotic resistance profile of Algerian E. coli strains isolated from diseased broilers. Materials and Methods: In this study, 43 avian E. coli strains isolated from chicken colibacillosis lesions at different years were analyzed to determine their contents in 10 virulence factors by polymerase chain reaction, antimicrobial susceptibility to 22 antibiotics belonging to six different chemical classes and genomic diversity by pulsed-field gel electrophoresis (PFGE). Results: Mainly E. coli isolates (58.1%) carried two at six virulence genes and the most frequent virulence gene association detected were ompT (protectin), hlyF (hemolysin) with 55.8% (p<0.001), and iroN, sitA (iron acquisition/uptake systems), and iss (protectin) with 41.8% (p<0.001). Some strains were diagnosed as virulent according to their virulence gene profile. Indeed, 23.25% of the isolates harbored iroN, ompT, hlyF, iss, and sitA combination, 14% ompT, hlyF, and frzorf4 (sugar metabolism), and 11,6% iroN, hlyF, ompT, iss, iutA (iron acquisition/uptake systems), and frzorf4. The chicken embryo lethality assay performed on five isolates confirmed the potential virulence of these strains. All isolates submitted to PFGE analysis yielded different genetic profiles, which revealed their diversity. Overall, 97.2% of the isolates were resistant to at least one antibiotic and 53.5% demonstrated multi-antimicrobial resistance to three different antimicrobial classes. The highest resistance levels were against nalidixic acid (83.4%), amoxicillin and ampicillin (83.3%), ticarcillin (80.5%), pipemidic acid (75%), and triméthoprim-sulfamethoxazole (66.6%). For beta-lactam class, the main phenotype observed belonged to broad-spectrum beta-lactamases. However, extended-spectrum beta-lactamase associated with three at six virulence factors was also detected in 13 isolates. Two of them were attested virulent as demonstrated in the embryo lethality test which constitutes a real public threat. Conclusion: It would be imperative in avian production to discourage misuse while maintaining constant vigilance guidelines and regulations, to limit and rationalize antimicrobial use.

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