High Biofilm-Forming Ability and Clonal Dissemination among Colistin-Resistant Escherichia coli Isolates Recovered from Cows with Mastitis, Diarrheic Calves, and Chickens with Colibacillosis in Tunisia

Sana Dhaouadi; Amel Romdhani; Wafa Bouglita; Salsabil Chedli; Soufiene Chaari; Leila Soufi; Ameur Cherif; Wissem Mnif; Mohamed Salah Abbassi; Ramzi Boubaker Elandoulsi

doi:10.3390/life13020299

High Biofilm-Forming Ability and Clonal Dissemination among Colistin-Resistant Escherichia coli Isolates Recovered from Cows with Mastitis, Diarrheic Calves, and Chickens with Colibacillosis in Tunisia

Life (Basel). 2023 Jan 20;13(2):299. doi: 10.3390/life13020299.

Authors

Affiliations

¹ ISBST, BVBGR-LR11ES31, Biotechpole Sidi Thabet, University of Manouba, Ariana 2020, Tunisia.
² Institut Supérieur de Biotechnologie de Sidi Thabet, Biotechpole Sidi Thabet, University of Manouba, Ariana 2020, Tunisia.
³ MEDIVET, Immeuble les Mimosas, 159 Avenue de l'UMA, La Soukra 2036, Tunisia.
⁴ Department of Chemistry, Faculty of Sciences and Arts in Balgarn, University of Bisha, P.O. Box 199, Bisha 61922, Saudi Arabia.
⁵ Institute of Veterinary Research of Tunisia, University of Tunis El Manar, Tunis 1006, Tunisia.
⁶ Laboratory of Bacteriological Research, Tunis 1006, Tunisia.

Abstract

Background: Escherichia coli (E. coli) is one of the main etiological agents responsible for bovine mastitis (BM), neonatal calf diarrhea (NCD), and avian colibacillosis (AC). This study aimed to assess resistance and virulence genes content, biofilm-forming ability, phylogenetic groups, and genetic relatedness in E. coli isolates recovered from clinical cases of BM, NCD, and AC.

Materials/methods: A total of 120 samples including samples of milk (n = 70) and feces (n = 50) from cows with BM and calves with NCD, respectively, were collected from different farms in Northern Tunisia. Bacterial isolation and identification were performed. Then, E. coli isolates were examined by disk diffusion and broth microdilution method for their antimicrobial susceptibility and biofilm-forming ability. PCR was used to detect antimicrobial resistance genes (ARGs), virulence genes (VGs), phylogenetic groups, and Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for their clonal relationship.

Results: Among the 120 samples, 67 E. coli isolates (25 from BM, 22 from AC, and 20 from NCD) were collected. Overall, 83.6% of isolates were multidrug resistant. Thirty-six (53.73%) isolates were phenotypically colistin-resistant (CREC), 28.3% (19/67) were ESBL producers (ESBL-EC), and forty-nine (73.1%) formed biofilm. The bla_TEM gene was found in 73.7% (14/19) of isolates from the three diseases, whilst the bla_CTXM-g-1 gene was detected in 47.3% (9/19) of isolates, all from AC. The most common VG was the fimA gene (26/36, 72.2%), followed by aer (12/36, 33.3%), cnf1 (6/36, 16.6%), papC (4/36, 11.1%), and stx1 and stx2 genes (2/36; 5.5% for each). Phylogenetic analysis showed that isolates belonged to three groups: A (20/36; 55.5%), B2 (7/36; 19.4%), and D (6/36; 16.6%). Molecular typing by ERIC-PCR showed high genetic diversity of CREC and ESBL E. coli isolates from the three animal diseases and gave evidence of their clonal dissemination within farms in Tunisia.

Conclusion: The present study sheds new light on the biofilm-forming ability and clonality within CREC and ESBL-EC isolated from three different animal diseases in Tunisian farm animals.

Keywords: E. coli; animal diseases; biofilm-forming ability; colistin resistance; genetic relatedness.

Grants and funding

This project was carried out within the framework of the MOBIDOC device, financed by the program of support to Education, MOtility, Research and Innovation (EMORI) subject of the financing agreement between the Government of the Republic of Tunisia and the European Union dated 31 March 2017 and having the accounting number ENI/2016/39506; ENI/2016/39771; ENI/2016/39772, and the subsidy contract under established between the ANPR and the European Union having the accounting number ENI/2017/387-249.