Mlangeni Lungile N, Ramatla Tsepo, Price Cormac, Thekisoe Oriel, Weldon Che
Unit for Environmental Sciences and Management, North-West University, Potchefstroom, 2531, South Africa.
Centre for Applied Food Safety and Biotechnology, Department of Life Sciences, Central University of Technology, 1 Park Road, Bloemfontein, 9300, South Africa.
Mol Biol Rep. 2025 Aug 2;52(1):778. doi: 10.1007/s11033-025-10857-w.
The gut microbiota of Testudines is fundamental to their digestion and overall health, yet remains a poorly investigated area in their biology, particularly in wild freshwater turtle (terrapins) and tortoise populations within South Africa. This study investigated the occurrence, diversity, virulence genes and antibiotic resistance of Escherichia coli isolated from Testudine gut microbiota and sediments at Timbavati Private Nature Reserve, South Africa.
Cloacal swab samples were collected from 36 wild Testudines and 20 sediment samples from temporary and permanent water bodies. Presumed E. coli isolates were confirmed by polymerase chain reaction (PCR) targeting the β-D glucuronidase (uidA) gene and further validated through 16 S rRNA gene sequencing. Phenotypic antibiotic resistance was evaluated with the Kirby-Bauer method, whilst resistance and virulence genes were identified using PCR assays. E. coli was detected in 54 (62%) of 87 isolates (23 Testudines and 31 sediments), confirmed by uidA PCR assay. Detected virulence genes included eaeA (42%), virF (22%), stx1 (16%), and stx2 (3%), and isolates exhibited resistance to erythromycin (53%), cephalothin (48%), and spectinomycin (40%). Resistance genes such as mcr-4 (70%), bla (46%), bla (64%), mcr-1 (42%), qnrA (16%), mcr-2 (22%), qnrD (11%), and tetW (2%) were also detected.
This study demonstrates that wild Testudines harbour E. coli in their gut and that it also occurs in their surrounding environment, with notable antibiotic resistance and virulence potential. The findings underscore the complexity of host-microbial interactions and the influence of environmental and host factors on microbial diversity, informing potential conservation and health management strategies for these reptilian species.
龟鳖目动物的肠道微生物群对其消化和整体健康至关重要，但在其生物学领域仍是一个研究较少的领域，尤其是在南非的野生淡水龟（水龟）和陆龟种群中。本研究调查了从南非蒂姆巴瓦蒂私人自然保护区的龟鳖目动物肠道微生物群和沉积物中分离出的大肠杆菌的发生情况、多样性、毒力基因和抗生素耐药性。
从36只野生龟鳖目动物采集泄殖腔拭子样本，并从临时和永久性水体采集20个沉积物样本。通过针对β-D葡萄糖醛酸酶（uidA）基因的聚合酶链反应（PCR）确认推定的大肠杆菌分离株，并通过16S rRNA基因测序进一步验证。采用 Kirby-Bauer 方法评估表型抗生素耐药性，同时使用PCR检测法鉴定耐药基因和毒力基因。通过uidA PCR检测法在87株分离株（23只龟鳖目动物和31份沉积物）中的54株（62%）中检测到大肠杆菌。检测到的毒力基因包括eaeA（42%）、virF（22%）、stx1（16%）和stx2（3%），分离株对红霉素（53%）、头孢噻吩（48%）和壮观霉素（40%）表现出耐药性。还检测到mcr-4（70%）、bla（46%）、bla（64%）、mcr-1（42%）、qnrA（16%）、mcr-2（22%）、qnrD（11%）和tetW（2%）等耐药基因。
本研究表明，野生龟鳖目动物的肠道中存在大肠杆菌，其周围环境中也有大肠杆菌，且具有显著的抗生素耐药性和毒力潜力。这些发现强调了宿主-微生物相互作用的复杂性以及环境和宿主因素对微生物多样性的影响，为这些爬行动物物种的潜在保护和健康管理策略提供了依据。
