Virulence Factors and Antimicrobial Resistance Profile of Escherichia Coli Isolated from Laying Hens in Italy

Abstract

Colibacillosis is the most common bacterial disease in the poultry industry. The isolation of Escherichia coli (E. coli) strains with multiple resistance to various classes of antimicrobials has been increasing in recent years. In this study, antimicrobial resistance features, serotyping and the presence of avian pathogenic Escherichia coli (APEC) virulence genes were investigated on a total of 71 E. coli strains isolated during outbreaks of colibacillosis in laying hens. The correlation between these features was evaluated. The most frequently isolated serogroups were O2 and O88. Resistance was often detected with nalidixic acid (49%) and ampicillin (38%), while all strains were sensitive to ceftiofur and florfenicol. Overall, 25% of the isolates showed resistance to at least three or more antimicrobial classes (multidrug-resistant strains), and 56% of the isolates were defined as APEC strains (due to the presence of at least five virulence genes). Correlation between the different parameters (virulence genes, serogroup and antimicrobial resistance) did not reveal relevant associations. The comparison of the obtained results with those of similar studies highlighted the importance of continuous monitoring in order to have a better understanding of colibacillosis. An evaluation of the national epidemiological situation would allow, especially with regard to antimicrobial resistance, to focus on the right measures in order to prioritize the available resources for effective disease control.

Assessing the Load, Virulence and Antibiotic-Resistant Traits of ESBL/Ampc E. coli from Broilers Raised on Conventional, Antibiotic-Free, and Organic Farms

“…However, few studies have focused on the occurrence of ESBL/AmpC-EC harbouring ExPEC/APEC virulence factors in the broiler production chain [ 4 , 10 ]. Virulence factors associated with APEC strains include adhesins encoded by a temperature-sensitive hemagglutinin gene ( tsh ), protectins encoded by an increased serum survival gene ( iss ), toxins encoded by an enteroaggregative toxin gene ( astA ) [ 11 , 12 ]. In Europe, the prevalence of ESBL/AmpC-EC-positive broilers at slaughterhouses varies broadly across countries, and is the highest in Italy (above 60%) [ 13 ].…”

Investigation of Salmonella spp. and Escherichia coli in the Snake-eyed lizard ( Ophisops elegans) (Sauria, Lacertidae) in the Çankırı Province of Turkey

“…and Escherichia coli are bacteria capable of colonizing the gut of various animals, and thus may threaten human and animal health. These bacterial pathogens have been isolated and identified from multiple avian and mammalian species that serve as their host (Şahan et al 2016, Gambi et al 2022, Hawwas et al 2022, Babacan 2023. While the presence of S. enterica serovars is frequently associated with diseases, E. coli serovars are generally accepted as commensal organisms (Lupolova et al 2017).…”

A comparative study on histopathological features of duodenum, jejunum, and ileum from broiler chicken with avian pathogenic Escherichia coli infection

“…Furthermore, to strengthen the identification, bacterial gene isolation can be detected by using visceral organs (Ibrahim et al, 2019). APEC strains have been associated with specific serogroups, namely O1, O2, and O78, while during colibacillosis outbreaks, the serogroup isolated are O8, O15, O18, O35, O88, O109, and O115 (Gambi et al, 2022).…”