Molecular characterization of avian pathogenic Escherichia coli from broiler chickens with colibacillosis

Abstract

Avian pathogenic Escherichia coli ( APEC ) causes extensive mortality in poultry flocks, leading to extensive economic losses. The aim of this study was to investigate the phenotypic and genotypic characteristics and antimicrobial resistance of recent APEC isolates. Of the 79 APEC isolates, the most predominant serogroup was O78 (16 isolates, 20.3%), followed by O2 (7 isolates, 8.9%) and O53 (7 isolates, 8.9%). Thirty-seven (46.8%) and six (7.6%) of the isolates belonged to phylogenetic groups D and B2, respectively, and presented as virulent extraintestinal E. coli . Among 5 analyzed virulence genes, the highest frequency was observed in hlyF (74 isolates, 93.7%), followed by iutA (72 isolates, 91.9%) gene. The distribution of the iss gene was significantly different between groups A/B1 and B2/D ( P < 0.05). All group B2 isolates carried all 5 virulence genes. APEC isolates showed high resistance to ampicillin (83.5%), nalidixic acid (65.8%), tetracycline (64.6%), cephalothin (46.8%), and ciprofloxacin (46.8%). The β-lactamases–encoding genes bla TEM-1 (23 isolates, 29.1%), bla CTX-M-1 (4 isolates, 5.1%), and bla CTX-M-15 (3 isolates, 3.8%); the aminoglycoside-modifying enzyme gene aac(3)-II (4 isolates, 5.1%); and the plasmid-mediated quinolone genes qnrA (10 isolates, 12.7%) and qnrS (2 isolates, 2.5%) were identified in APEC isolates. The tetA (37 isolates, 46.8%) and sul2 (20 isolates, 25.3%) were the most prevalent among tetracycline and sulfonamide resistant isolates, respectively. This study indicates that APEC isolates harbor a variety of virulence and resistance genes; such genes are often associated with plasmids that facilitate their transmission between bacteria and should be continuously monitored to track APEC transmission in poultry farms.

Effects of in ovo probiotic administration on the incidence of avian pathogenic Escherichia coli in broilers and an evaluation on its virulence and antimicrobial resistance properties

“…The APEC-like positive isolates were examined by PCR for 14 antimicrobial resistance genes conferring resistance to β-lactamase ( blaTEM ), aminoglycoside ( aac(3)-VIa, aac(3)-VIb , aph(3′)-Ia , and aadA ), tetracycline ( tetA , tetB ), trimethoprim ( dfr1 , dfr7 , and dfr17 ), quaternary ammonium compounds ( QAC ) ( qacEΔ ), quinolone antibiotics ( qnr ), sulfonamide ( sul1 ), and integrase ( intl1 ) as described previously by Kim et al., 2020 . In addition, 11 heavy metal resistance genes for conferring resistance to arsenic ( arsC ), mercury ( merA ), tellurite ( terD , terF , terX , and terY3 ), copper ( pcoA , pcoD , and pcoE ), and silver ( silE , silP ) were tested.…”

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

“…Although E. coli is part of the normal bacterial microbiota of the intestinal tract, other mucosal surfaces of hosts, and the poultry farm environment, few of these strains are endowed with specific virulence factors that define the APEC phenotype [ 3 ]. Most APEC strains are phylogenetically associated with extra-intestinal location [ 4 , 5 ]. Principally, they are associated with respiratory tract and systemic infections [ 6 ].…”

“…[ 9 , 10 ]. Thus, APEC is a major cause of extensive economic loss in the poultry industry due to high morbidity and mortality [ 4 ]. Both the broiler and layer farms are affected by APEC.…”

Prevalence of Antimicrobial Resistance (AMR) <em>Salmonella spp</em>. and <em>Escherichia coli</em> Isolated From Broilers in East Coast Malaysia

“…Salmonellosis is caused by non-typhoidal Salmonella and typically characterised by gastroenteritis syndrome in human (Antunes et al, 2016). Avian colibacillosis is a significant infectious disease caused by pathogenic E. coli strains and causes massive economic losses to the poultry industry due to high morbidity, mortality, and cost of treatment and prevention (Kim et al, 2020). The condition is characterised by respiratory infection, yolk sac infection, coli granuloma, enteritis, cellulitis omphalitis, swollen head syndrome, septicemia, polyserositis, and salpingitis (Kabir, 2010).…”