Dhaouadi Sana, Romdhani Amel, Bouglita Wafa, Chedli Salsabil, Chaari Soufiene, Soufi Leila, Cherif Ameur, Mnif Wissem, Abbassi Mohamed Salah, Elandoulsi Ramzi Boubaker
ISBST, BVBGR-LR11ES31, Biotechpole Sidi Thabet, University of Manouba, Ariana 2020, Tunisia.
Institut Supérieur de Biotechnologie de Sidi Thabet, Biotechpole Sidi Thabet, University of Manouba, Ariana 2020, Tunisia.
Life (Basel). 2023 Jan 20;13(2):299. doi: 10.3390/life13020299.
() 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 isolates recovered from clinical cases of BM, NCD, and AC.
MATERIALS/METHODS: A total of 120 samples including samples of milk ( = 70) and feces ( = 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, 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.
Among the 120 samples, 67 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 gene was found in 73.7% (14/19) of isolates from the three diseases, whilst the gene was detected in 47.3% (9/19) of isolates, all from AC. The most common VG was the A gene (26/36, 72.2%), followed by (12/36, 33.3%) (6/36, 16.6%)C (4/36, 11.1%), and 1 and 2 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 isolates from the three animal diseases and gave evidence of their clonal dissemination within farms in Tunisia.
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.
（）是导致牛乳腺炎（BM）、新生犊牛腹泻（NCD）和禽大肠杆菌病（AC）的主要病原体之一。本研究旨在评估从BM、NCD和AC临床病例中分离出的（）菌株的耐药性和毒力基因含量、生物膜形成能力、系统发育群以及遗传相关性。
材料/方法：从突尼斯北部不同农场收集了总共120份样本，分别为患有BM的奶牛的牛奶样本（n = 70）和患有NCD的犊牛的粪便样本（n = 50）。进行了细菌分离和鉴定。然后，通过纸片扩散法和肉汤微量稀释法检测分离菌株的抗菌药敏性和生物膜形成能力。采用聚合酶链反应（PCR）检测抗菌耐药基因（ARGs）、毒力基因（VGs）、系统发育群，并采用肠杆菌重复基因间共识聚合酶链反应（ERIC-PCR）分析其克隆关系。
在120份样本中，共收集到67株（）分离株（25株来自BM，22株来自AC，20株来自NCD）。总体而言，83.6%的分离株具有多重耐药性。36株（53.73%）分离株表型上对黏菌素耐药（CREC），28.3%（19/67）为超广谱β-内酰胺酶产生菌（ESBL-EC），49株（73.1%）形成生物膜。在三种疾病的分离株中，73.7%（14/19）检测到（）基因，而（）基因在47.3%（9/19）的分离株中被检测到，所有这些分离株均来自AC。最常见的毒力基因是（）A基因（26/36，72.2%），其次是（）（12/36，33.3%）（）（6/36，16.6%）（）C（4/36，11.1%），以及（）1和（）2基因（2/36；各占5.5%）。系统发育分析表明，分离株属于三个组：A组（20/36；55.5%）、B2组（7/36；19.4%）和D组（6/36；16.
