Multidrug resistance, biofilm formation, and virulence genes of Escherichia coli from backyard poultry farms

Abstract

Background and Aim: Backyard chicken flocks have traditionally been regarded as an essential food source in developed countries; however, they may act as reservoirs and spread various zoonotic bacterial pathogens. This study was designed to investigate the prevalence, phenotypic resistance, biofilm formation (BF), and pathotypes of Escherichia coli isolates from backyard poultry farms. Materials and Methods: Cloacal swabs (n=150) and internal organs (n=150) were collected from 30 backyard chicken flocks; 20 of them were experiencing systemic infection, and the other ten were apparently healthy. Samples were bacteriologically examined for E. coli isolation. Isolates were identified biochemically by the VITEK® 2 COMPACT system (BioMérieux, France). For molecular identification, 16S rRNA was amplified and sequenced. Ten antimicrobials were selected for E. coli antimicrobial susceptibility testing. The minimum inhibitory concentration for each antimicrobial was determined. The extended-spectrum β-lactamase activity in isolates was investigated using cephalosporin/clavulanate combination disks. The ability of isolates for BF was determined by the microtiter plate method. Thirteen virulence genes linked to different E. coli pathotypes and two serotype-related genes were investigated by real-time polymerase chain reaction. Results: Eighty-six E. coli strains were isolated from 30 backyard chicken flocks. The isolates were biochemically identified to the species level. Genetically, sequences of the 16S rRNA gene showed >98% identity with E. coli in the National Center for Biological Information database. The frequency of isolation from diseased flocks was significantly higher (p<0.05) than apparently healthy flocks; 63.9% of the isolates were recovered from cloacal swabs and 36.04% were recovered from internal organs. E. coli isolates showed high resistance to ampicillin (AMP; 75.6%), gentamicin (39.5%), and tetracycline (29.1%). However, none of the isolates were resistant to imipenem. A variable drug resistance profile for E. coli isolates was reported. Twenty-one (24.4%) isolates were sensitive to all ten antimicrobials. Seven (8.1%) isolates were resistant only to AMP, and 28 (32.6%) were resistant to two antimicrobials, whereas the remaining 30 (34.9%) isolates showed multidrug resistance (MDR). Of the 86 isolates, 8 (9.3%) were confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli by the combination disk diffusion method. All ESBL isolates were MDR with an MDR index of 0.5-0.6. Fifty-seven (66.3%) isolates were capable of forming biofilms; 22 (25.6%) of them were strong biofilm producers, 24 (27.9%) moderate producers, and 11 (12.8%) weak producers. A statistically significant pairwise correlation was obtained for MDR versus BF (r=0.512) and MDR index versus BF (r=0.556). Based on virulence gene profiles, five pathotypes were identified, including enteropathogenic E. coli (39.5%), avian pathogenic E. coli (32.53%), enterohemorrhagic E. coli (EHEC; 9.3%), enterotoxigenic E. coli (ETEC; 5.8%), and enteroaggregative E. coli (EAEC; 1.2%). The lower frequency of EAEC and ETEC was statistically significant than other pathotypes. Three isolates were identified as O157 based on the detection of the rbfO157 gene. Conclusion: This study reported a high prevalence of MDR, suggesting the misuse of antimicrobials in backyard chicken farms. The emergence of ESBL and EHEC isolates in backyard chickens is a public health concern. Furthermore, the backyard flocks environment may harbor different pathogenic bacteria that may enhance the persistence of infection and the transmission to in-contact humans. Regular monitoring for the occurrence of MDR and the zoonotic pathotypes among E. coli in backyard chicken flocks is recommended, as these bacteria can transmit to humans through food products or contaminated environments.

Antimicrobial Resistance, Biofilm Formation, and Virulence Genes in Enterococcus Species from Small Backyard Chicken Flocks

“…Backyard chickens are considered to be a vector for disseminating several zoonotic diseases, including Salmonella, Campylobacter, enteropathogenic E. coli, and several antibioticresistant microorganisms [42][43][44]. Moreover, enterococci, notably E. faecium and E. faecalis, have emerged as major multidrug-resistant zoonotic bacteria due to the widespread use of antibiotics in human and veterinary treatments [45].…”

Backyard poultry: exploring non-intensive production systems

“…*Data obtained for MG/MS concern ELISA analysis; APEC were obtained with end-point PCR analysis in Italy, Egypt, and Saudi Arabia, while in Ethiopia with isolation with standard bacteriological methods; Salmonella were obtained with isolation with standard bacteriological method and end-point PCR, respectively in Bosnia Herzegovina and Australia and finally, Campylobacter were obtained with isolation with the standard bacteriological method in New Zealand and Egypt, while in Australia with end-point PCR. Ecuador ( Hernandez-Divers et al, 2006 ), Belgium ( Haesendonck et al, 2014 ), West Indies ( Bolfa et al, 2019 ), Ethiopia ( Sarba et al, 2019 ), Egypt ( El-Tras et al, 2015 ; Ibrahim et al, 2019 ), Italy ( Sgariglia et al, 2019 ), Sudi Arabia ( Al-Marri et al, 2021 ), Bosnia Herzegovina ( Koro et al, 2022 ), Australia ( Keerthirathne et al, 2022 ), and New Zealand ( Anderson et al, 2012 ). …”

“…E. coli is a bacterium of the Enterobacteriaceae family ( Al-Marri et al, 2021 ). According to the pathogeneses, E. coli can be classified into three main groups: extraintestinal pathogenetic E. coli ( ExPEC ), intestinal pathogenetic E. coli ( InEC ), and commensal strains ( Ovi et al, 2023 ).…”

“…According to the pathogeneses, E. coli can be classified into three main groups: extraintestinal pathogenetic E. coli ( ExPEC ), intestinal pathogenetic E. coli ( InEC ), and commensal strains ( Ovi et al, 2023 ). In poultry, avian pathogenic E. coli ( APEC ) is found in the gut microbiota of healthy birds, but according to their health condition, it can be responsible for extraintestinal infections, causing colibacillosis ( Al-Marri et al, 2021 ). In a study conducted in 30 backyard farms, 86 different E. coli strains were isolated and 33% were avian pathogenic E. coli ( Al-Marri et al, 2021 ).…”

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

“…The public health significance of avian E. coli is primarily related to antibiotic resistance events, such as carry over and cross resistance [ 4 ]. Moreover, zoonotic potential has been identified in some ExPEC serogroups, i.e., Shiga toxin-producing E. coli O157 [ 5 , 6 ]. Disease control is performed through antimicrobial treatments and appropriate farm management, along with novel approaches such as the use of probiotics and bacteriophages, aiming to reduce predisposing factors [ 1 , 3 ].…”