scholarly journals The irp2 and fyuA genes in High Pathogenicity Islands are involved in the pathogenesis of infections caused by avian pathogenic Escherichia coli (APEC)

2016 ◽  
Vol 19 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Jian Tu ◽  
Ting Xue ◽  
Kezong Qi ◽  
Ying Shao ◽  
Boyan Huang ◽  
...  

Abstract Avian pathogenic Escherichia coli (APEC) is a major bacterial infectious disease that may lead to local or systemic infections in chickens with clinical manifestations. The irp2-fyuA gene cluster has been confirmed to be the main genes involved in the synthesis of HPI. The objective of this study was to determine the influence of the irp2 and fyuA genes in the high pathogenicity island (HPI) of avian pathogenic Escherichia coli (APEC) on its pathogenicity by knocking out these genes. The ΔAE17 (lacking irp2) and ΔΔAE17 (lacking irp2 and fyuA) strains of APEC were constructed. The ΔAE17 and ΔΔAE17 strains showed significantly impaired capacity to adhere onto DF-1 cells. The LD50 results indicated that the virulence of the ΔAE17 and ΔΔAE17 strains was decreased in comparison with that of the AE17 strain. We concluded that the knock-out of the core HPI genes weakened APEC adhesion onto DF-1 cells, inhibited transcription of virulence genes, and reduced pathogenicity in chicks. The effects of genetic deletion of irp2 and fyuA on APEC were more severe than those produced by deletion of irp2 only, indicating that irp2 and fyuA co-regulate APEC pathogenicity.

2019 ◽  
Vol 59 (2) ◽  
pp. 338
Author(s):  
S. N. Magray ◽  
S. A. Wani ◽  
Z. A. Kashoo ◽  
M. A. Bhat ◽  
S. Adil ◽  
...  

The present study has determined the serological diversity, virulence-gene profile and in vitro antibiogram of avian pathogenic Escherichia coli (APEC) isolates from broiler chickens in India suspected to have died of colibacillosis. The virulence-gene profile of APEC was compared with that of the Escherichia coli isolates from faeces of apparently healthy chickens, called avian faecal E. coli (AFEC). In total, 90 representative isolates of APEC and 63 isolates of AFEC were investigated in the present study. The APEC were typed into 19 serogroups, while some isolates were rough and could not be typed. Most prevalent serogroup was O2 (24.44%). Among the eight virulence genes studied, the prevalence of seven genes (iss, iucD, tsh, cva/cvi, irp2, papC and vat) was significantly higher in APEC than in AFEC isolates. However, there was no significant difference between APEC and AFEC isolates for possession of astA gene. The most frequent gene detected among the two groups of organisms was iss, which was present in 98.88% and 44.44% of APEC and AFEC isolates respectively. The in vitro antibiogram showed that the majority (96.6%) of APEC isolates were resistant to tetracycline, while 82.2% were resistant to cephalexin, 78.8% to cotrimoxazole, 68.8% to streptomycin and 63.3% to ampicillin. However, most of them (84.45%) were sensitive to gentamicin. Thus, it is concluded that APEC from the broiler chickens carried putative virulence genes that attributed to their pathogenicity. Furthermore, the majority of APEC isolates were found to be multi-drug resistant, which, in addition to leading treatment failures in poultry, poses a public health threat.


2021 ◽  
Vol 7 (1) ◽  
pp. 967-972
Author(s):  
Farzana Ehetasum Hossain ◽  
Saiful Islam ◽  
Md Aminul Islam ◽  
Shariful Islam ◽  
Firoz Ahmed

Avian colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the major infectious diseases of poultry that bring about great economic loss for the Bangladesh poultry industry. The present study aimed to determine the virulence genes of avian pathogenic Escherichia coli (APEC) from cases of colibacillosis in poultry at the Noakhali district of Bangladesh. Currently, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). A total of 24 (twenty-four) Escherichia coli isolates were collected and presumptively identified from 8 (eight) colibacillosis cases from 4 commercial broiler poultry farms (2 broilers per farm) in Noakhali, Bangladesh. The pathogenesis of Escherichia coli involves a wide range of different virulence genes. At this point, four virulence genes, iutA, hlyF, iroN, and iss were detected by PCR analysis. It has been observed that iutA, iss, hlyF, and iroN genes were found in 7(29.16%), 20(83.33%), 22(91.66%), and 24(100%) APEC isolates respectively. Furthermore, out of the twenty-four APEC isolates, six (25%) isolates had four virulence genes, fourteen (58.33%) isolates carried at least three virulence genes, three (12.5%) isolates carried two genes and one (4.16%) isolates had one virulence gene. Most importantly. six types of virulence gene profiles existed within the APEC isolates from which profile number 3 (hlyF, iroN, iss) having 13 (54.16%) isolates were predominant. The occurrence of APEC isolates of this region which is responsible for avian colibacillosis cases can be a matter of concern from the public health point of view. Future investigations will be able to utilize these virulence genes to identify APEC in Bangladesh helping in the diagnosis and prevention of colibacillosis in poultry. Bioresearch Commu. 7(1): 967-972, 2021 (January)


2020 ◽  
Vol 8 (7) ◽  
pp. 1021 ◽  
Author(s):  
Samina Ievy ◽  
Md. Saiful Islam ◽  
Md. Abdus Sobur ◽  
Mithun Talukder ◽  
Md. Bahanur Rahman ◽  
...  

Avian pathogenic Escherichia coli (APEC) causes significant economic losses in poultry industries. Here, we determined for the first time in Bangladesh, the prevalence of APEC-associated virulence genes in E. coli isolated from layer farms and their antibiotic resistance patterns. A total of 99 samples comprising internal organs, feces, and air were collected from 32 layer farms. Isolation was performed by culturing samples on eosin–methylene blue agar plates, while the molecular detection of APEC was performed by PCR, and antibiograms were performed by disk diffusion. Among the samples, 36 were positive for the APEC-associated virulence genes fimC, iucD, and papC. Out of 36 isolates, 7, 18, and 11 were positive, respectively, for three virulence genes (papC, fimC, and iucD), two virulence genes, and a single virulence gene. Although the detection of virulence genes was significantly higher in the internal organs, the air and feces were also positive. The antibiograms revealed that all the isolates (100%) were resistant to ampicillin and tetracycline; 97.2%, to chloramphenicol and erythromycin; 55.5%, to enrofloxacin; 50.0%, to norfloxacin and ciprofloxacin; 19.4%, to streptomycin; 11.1%, to colistin; and 8.33%, to gentamicin. Interestingly, all the isolates were multidrug-resistant (MDR). Spearman’s rank correlation coefficient analysis revealed the strongest significant correlation between norfloxacin and ciprofloxacin resistance. This is the first study in Bangladesh describing the molecular detection of APEC in layer farms. Isolated APEC can now be used for detailed genetic characterization and assessing the impact on public health.


2006 ◽  
Vol 188 (16) ◽  
pp. 5975-5983 ◽  
Author(s):  
Timothy J. Johnson ◽  
Sara J. Johnson ◽  
Lisa K. Nolan

ABSTRACT Avian pathogenic Escherichia coli (APEC), an extraintestinal pathogenic E. coli causing colibacillosis in birds, is responsible for significant economic losses for the poultry industry. Recently, we reported that the APEC pathotype was characterized by possession of a set of genes contained within a 94-kb cluster linked to a ColV plasmid, pAPEC-O2-ColV. These included sitABCD, genes of the aerobactin operon, hlyF, iss, genes of the salmochelin operon, and the 5′ end of cvaB of the ColV operon. However, the results of gene prevalence studies performed among APEC isolates revealed that these traits were not always linked to ColV plasmids. Here, we present the complete sequence of a 174-kb plasmid, pAPEC-O1-ColBM, which contains a putative virulence cluster similar to that of pAPEC-O2-ColV. These two F-type plasmids share remarkable similarity, except that they encode the production of different colicins; pAPEC-O2-ColV contains an intact ColV operon, and pAPEC-O1-ColBM encodes the colicins B and M. Interestingly, remnants of the ColV operon exist in pAPEC-O1-ColBM, hinting that ColBM-type plasmids may have evolved from ColV plasmids. Among APEC isolates, the prevalence of ColBM sequences helps account for the previously observed differences in prevalence between genes of the “conserved” portion of the putative virulence cluster of pAPEC-O2-ColV and those genes within its “variable” portion. These results, in conjunction with Southern blotting and probing of representative ColBM-positive strains, indicate that this “conserved” cluster of putative virulence genes is primarily linked to F-type virulence plasmids among the APEC isolates studied.


Author(s):  
Joshua Mbanga ◽  
Yvonne O. Nyararai

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.


2016 ◽  
Vol 19 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Jian Tu ◽  
Boyan Huang ◽  
Yu Zhang ◽  
Yuxi Zhang ◽  
Ting Xue ◽  
...  

Abstract Avian pathogenic Escherichia coli (APEC) infections are a very important problem in the poultry industry. PhoP-PhoQ is a two-component system that regulates virulence genes in APEC. In this study, we constructed strains that lacked the PhoP or PhoQ genes to assess regulation of APEC pathogenicity by the PhoP-PhoQ two-component system. The PhoP mutant strain AE18, PhoQ mutant strain AE19, and PhoP/PhoQ mutant strain AE20 were constructed by the Red homologous recombination method. Swim plates were used to evaluate the motility of the APEC strains, viable bacteria counting was used to assess adhesion and invasion of chick embryo fibroblasts, and Real-Time PCR was used to measure mRNA expression of virulence genes. We first confirmed that AE18, AE19, and AE20 were successfully constructed from the wild-type AE17 strain. AE18, AE19, and AE20 showed significant decreases in motility of 70.97%, 83.87%, and 37.1%, respectively, in comparison with AE17. Moreover, in comparison with AE17, AE18, AE19, and AE20 showed significant decreases of 63.11%, 65.42%, and 30.26%, respectively, in CEF cell adhesion, and significant decreases of 59.83%, 57.82%, and 37.90%, respectively, in CEF cell invasion. In comparison with AE17, transcript levels of sodA, polA, and iss were significantly decreased in AE18, while transcript levels of fimC and iss were significantly decreased in AE19. Our results demonstrate that deletion of PhoP or PhoQ inhibits invasion and adhesion of APEC to CEF cells and significantly reduces APEC virulence by regulating transcription of virulence genes.


Author(s):  
Saroj Sankhi ◽  
Rebanta Kumar Bhattarai ◽  
Hom Bahadur Basnet ◽  
Nirmal Raj Marasine ◽  
Himal Luitel ◽  
...  

This study aimed to identify, evaluate the antibiotic resistance pattern and detect virulence genes iss, and ompT in avian pathogenic Escherichia coli (APEC) from broiler chickens in central Nepal. To determine the antibiotic resistance pattern of the obtained isolates, the Kirby-Bauer disc diffusion method was used with six different commercial antibiotic discs: Amikacin, Gentamycin, Ciprofloxacin, Doxycycline, Chloramphenicol and Levofloxacin. A polymerase chain reaction (PCR) assay was used for the selected isolates (n=40) to screen the presence of the iss and ompT genes after the extraction of DNA using the boiling method Out of 60 suspected Colibacillosis liver samples, 40 were confirmed as E. coli positive The antibiogram profile revealed maximum resistance to Doxycycline (87.5%), followed by Levofloxacin (72.5%), Ciprofloxacin (67.5%), Chloramphenicol (40.0%), Gentamycin (32.5%) and Amikacin (10.0%).. The presence of the iss and ompT genes was found to be 100.0% and 90.0%, respectively. APEC was found to be highly resistant to most of the antibiotics. Virulence-associated genes iss and ompT were obtained at high percentages from Colibacillosis suspected broiler chickens in Chitwan, Nepal. These finding suggests that the judicial use of antimicrobials is compulsory to check antibiotic resistance and Colibacillosis outbreaks in poultry farms.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0239107
Author(s):  
George Kazibwe ◽  
Phionah Katami ◽  
Ruth Alinaitwe ◽  
Stephen Alafi ◽  
Ann Nanteza ◽  
...  

Avian Pathogenic Escherichia coli (APEC) cause colibacillosis leading to significant economic losses in the poultry industry. This laboratory-based study aimed at establishing stocks of avian pathogenic Escherichia coli lytic bacteriophages, for future development of cocktail products for colibacillosis management. The study determined the antibiotic susceptibility; phylogenetic categories, occurrence of selected serotypes and virulence genes among Escherichia coli stock isolates from chicken colibacillosis cases; and evaluated bacteriophage activity against the bacteria. Escherichia coli characterization was done through phenotypic and multiplex PCR methods. Bacteriophage isolation and preliminary characterization was achieved using the spot assay and overlay plating techniques. Fifty-six (56) isolates were phenotypically confirmed as E. coli and all exhibited resistance to at least one antimicrobial agent; while multi-drug resistance (at least three drugs) was encountered in 50 (89.3%) isolates. The APEC isolates mainly belonged to phylogroups A and D, representing 44.6% and 39.3%, respectively; whereas serotypes O1, O2 and O78 were not detected. Of the 56 isolates, 69.6% harbored at least one virulence gene, while 50% had at least four virulence genes; hence confirmed as APEC. Virulence genes, ompT and iutA were the most frequent in 33 (58.9%) and 32 (57.1%) isolates respectively; while iroN least occurred in 23 (41.1%) isolates. Seven lytic bacteriophages were isolated and their host range, at 1×108 PFU/ml, varied from 1.8% to 17.9% of the 56 APEC isolates, while the combined lytic spectrum was 25%. Phage stability was negatively affected by increasing temperatures with both UPEC04 and UPEC10 phages being undetectable at 70°C; whereas activity was detected between pH 2 and 12. The high occurrence of APEC isolates resistant against the commonly used antibiotics supports the need for alternative strategies of bacterial infections control in poultry. The low host range exhibited by the phages necessitates search for more candidates before in-depth phage characterization and application.


2019 ◽  
Vol 7 (1) ◽  
pp. 4-8
Author(s):  
Payam Haghighi Khoshkhoo ◽  
Hadi Pourtaghi ◽  
Gita Akbariazad ◽  
Saeed Mokhayeri

Background: Avian pathogenic Escherichia coli (APEC) causes economic losses in the chicken industry worldwide. Objective: In this study, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR). Materials and Methods: A total of 60 Escherichia coli isolates were collected from 60 colibacillosis cases from 30 broiler poultry farms in Alborz, Tehran, and Golestan provinces, Iran. After identification by biochemical tests, DNA was extracted by boiling method and 5 virulence-associated genes including: iutA, hlyF, iroN, ompT, and iss were detected by 2 multiplex PCR protocols. Results: Of the 60 APEC isolates, 26 (43.3%) isolates had at least three virulence genes from which 12 (20%) isolates were positive for all 5 virulence genes, whereas 34 (56.6%) carried no investigated virulence genes. Presence of iutA, hlyF, iroN, ompT, and iss genes in the APEC isolates were 17 (28.3%), 17 (28.3%), 24 (40%), 26 (43.3%), and 23 (38.3%), respectively. Conclusion: According to the results, four different virulence-associated gene profiles were seen in isolates, from which profile 1 with 12 (20%) isolates was predominant. These findings were in agreement with the previous reports.


2020 ◽  
Vol 8 (8) ◽  
pp. 1135
Author(s):  
Otun Saha ◽  
M. Nazmul Hoque ◽  
Ovinu Kibria Islam ◽  
Md. Mizanur Rahaman ◽  
Munawar Sultana ◽  
...  

The avian pathogenic Escherichia coli (APEC) strains are the chief etiology of colibacillosis worldwide. The present study investigated the circulating phylotypes, existence of virulence genes (VGs), and antimicrobial resistance (AMR) in 392 APEC isolates, obtained from 130 samples belonged to six farms using both phenotypic and PCR-based molecular approaches. Congo red binding (CRB) assay confirmed 174 APEC isolates which were segregated into ten, nine, and eight distinct genotypes by RAPD assay (discriminatory index, DI = 0.8707), BOX-PCR (DI = 0.8591) and ERIC-PCR (DI = 0.8371), respectively. The combination of three phylogenetic markers (chuA, yjaA and DNA fragment TspE4.C2) classified APEC isolates into B23 (37.36%), A1 (33.91%), D2 (11.49%), B22 (9.20%), and B1 (8.05%) phylotypes. Majority of the APEC isolates (75–100%) harbored VGs (ial, fimH, crl, papC, and cjrC). These VGs (papC and cjrC) and phylotypes (D2 and B2) of APEC had significant (p = 0.004) association with colibacillosis. Phylogenetic analysis showed two distinct clades (clade A and clade B) of APEC, where clade A had 98–100% similarity with E. coli APEC O78 and E. coli EHEC strains, and clade B had closest relationship with E. coli O169:H41 strain. Interestingly, phylogroups B2 and D2 were found in the APEC strains of both clades, while the strains from phylogroups A1 and B1 were found in clade A only. In this study, 81.71% of the isolates were biofilm formers, and possessed plasmids of varying ranges (1.0 to 54 kb). In vitro antibiogram profiling revealed that 100% isolates were resistant to ≥3 antibiotics, of which 61.96%, 55.24%, 53.85%, 51.16% and 45.58% isolates in phylotypes B1, D2, B22, B23, and A1, respectively, were resistant to these antimicrobials. The resistance patterns varied among different phylotypes, notably in phylotype B22, showing the highest resistance to ampicillin (90.91%), nalidixic acid (90.11%), tetracycline (83.72%), and nitrofurantoin (65.12%). Correspondence analysis also showed significant correlation among phylotypes with CRB (p = 0.008), biofilm formation (p = 0.02), drug resistance (p = 0.03), and VGs (p = 0.06). This report demonstrated that B2 and A1 phylotypes are dominantly circulating APEC phylotypes in Bangladesh; however, B2 and D2 are strongly associated with the pathogenicity. A high prevalence of antibiotic-resistant APEC strains from different phylotypes suggest the use of organic antimicrobial compounds, and/or metals, and the rotational use of antibiotics in poultry farms in Bangladesh.


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