Incidence, Pathotyping, and Antibiotic Susceptibility of Avian Pathogenic Escherichia coli among Diseased Broiler Chicks

Abstract

A total of 54 broiler flocks during the first two weeks of life was used to investigate the incidence of avian pathogenic E. coli in Egypt; 28 isolates (51.85%) were revealed by colony morphology and biochemical identification which then investigated for their serogroups and only 18/28 isolates were serotyped. The most prevalent serotypes were O115, O142, O158, O55, O125, O114, O27, O20, and O15. By application of polymerase chain reaction (PCR), 83.3% (15/18) of the serotyped isolates were confirmed to be E. coli, and 93.3% (14/15), 46.6% (7/15), and 20% (3/15) of isolates harbored the iss, iutA, and fimH genes, respectively. Virulence testing of the selected 13 APEC isolates on the specific-pathogen-free (SPF) chicks revealed them to be highly virulent (15.4%), moderately virulent (23.1%), and avirulent (61.5%); however, all isolates (100%) were extremely virulent towards SPF embryonated chicken eggs. Antibiotic resistance (100% of isolates (n = 13)) was observed for ampicillin, amoxycillin–clavulanic acid, and tetracyclines, colistin (92.31%; 12/13), doxycycline and spiramycin (84.62%; 11/13), florfenicol (69.23%; 9/13), cefotaxime (61.54%; 8/13), and ciprofloxacin (53.85%; 7/13). The highest percentage of sensitivity (53.85% of isolates; 7/13) was recorded for ofloxacin and enrofloxacin followed by gentamycin (46.15%; 6/13). The results suggest that the diagnosis of APEC with PCR is rapid and more accurate than traditional methods for E. coli identification; moreover, the presence or absence of iss, iutA, and/or fimH genes is not an indicator of in vivo pathogenicity of APEC. Thus, further studies, including a wider range of virulence genes and gene sequencing, are required. In addition, serotyping has no effect on the virulence of APEC.

Molecular Detection of Avian Pathogenic Escherichia coli (APEC) for the First Time in Layer Farms in Bangladesh and Their Antibiotic Resistance Patterns

“…We found all the APEC isolates to be resistant to ampicillin and tetracycline, and a high prevalence of resistance to chloramphenicol, erythromycin, enrofloxacin, norfloxacin, and ciprofloxacin. A 100% resistance of APEC isolates to ampicillin and tetracycline was also reported by Awad et al [ 67 ]. In addition, Subedi et al [ 17 ] and Ozawa et al [ 68 ] reported higher percentages of APEC resistance to ampicillin, tetracycline, ciprofloxacin, and norfloxacin.…”

Avian Pathogenic Escherichia coli (APEC): An Overview of Virulence and Pathogenesis Factors, Zoonotic Potential, and Control Strategies

“…Adherence in APEC is facilitated primarily by type 1 fimbriae, P fimbriae, and S fimbriae [ 2 , 31 ]. Several genes encoding these fimbriae and additional adhesins, fim H, fim C (type 1 fimbriae), pap A, pap C, pap EF, pap G I, pap G II, pap GIII, fel A (P fimbriae), sfa / sfa S (S fimbriae), foc GE (F1C fimbriae), afa IBC (afimbriae), lpf A, lpf 0141, lpf 0154 (long polar fimbriae), mat / ecp A (fimbrillin), flg E (flagellar hook), crl , csg (curli), tsh (temperature-sensitive haemagglutinin), bma E (M hemagglutinin), hra / hrl A/ hek (heat-resistant agglutinin), iha (IrgA homologue adhesin), yqi G (putative outer membrane usher protein), and kii (K capsule encoding genes) have been reported in APEC [ 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ]. These adhesins also mediate motility, biofilm formation, and APEC survival in macrophages [ 31 ].…”

“…Many antibiotics belonging to different classes, such as tetracyclines (tetracycline, oxytetracycline, chlortetracycline), sulfonamides (sulfadimethoxine, trimethoprim, sulfadiazine, sulfamethazine, sulfaquinoxaline, ormethoprim), aminoglycosides (apramycin, gentamicin, neomycin, spectinomycin), penicillins (amoxicillin, ampicillin), cephalosporins (ceftiofur), quinolones (danofloxacin, sarafloxacin, enrofloxacin), polymyxins (colistin), chloramphenicols (florfenicol), macrolides (erythromycin), and lincosamides (lincomycin) have been used in poultry industry worldwide for the control of APEC infections [ 23 ]. However, APEC resistance to multiple antibiotics has been reported [ 32 , 34 , 35 , 51 , 53 , 54 , 70 , 71 , 72 , 73 , 107 , 108 , 108 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 ], which limits the use of these antibiotics and suggests a challenge ahead in using these antibiotics. Table 2 provides a summary of antibiotic resistance and resistance genes (mechanisms) reported worldwid...…”

The Avian Pathogenic Escherichia coli (APEC) pathotype is comprised of multiple distinct, independent genotypes

“…Within the poultry gastrointestinal tract, bacteria exist at high densities thus facilitating intra-and inter-species, as well as inter-genera, horizontal transfer of resistance genes (Cordoni et al, 2016;Card et al, 2017). APEC are often resistant to a range of antimicrobial compounds including tetracyclines, chloramphenicol, sulphonamides fluoroquinolones and β-lactams (Solà-Ginés et al, 2015;Awad et al, 2016;Hornsey et al, 2019;Awad et al, 2020). The genes conferring resistance are frequently encoded on integrons and plasmids, as well as other mobile genetic elements, which can be passed between permissive APEC strains and other species (Hornsey et al, 2019;Cummins et al, 2019).…”

“…APEC classification is traditionally based on serotyping and virulence genotyping, with the gold standard for designation of a pathogenic E. coli isolate as APEC being confirmation of virulence in day-old chicks or embryos (Dho & Lafont, 1982;Awad et al, 2020.). However, this is now rarely performed due to a lack of suitable facilities, and ethical concerns.…”