Emara Mona S, Ammar Ahmed M, Abdelwahab Ashraf M O, Elgdawy Attia A, Abdelkhalek Adel, Pet Elena, Dumitrescu Gabi, Ahmadi Mirela, Abd El-Aziz Norhan K
Animal Health Research Institute, Zagazig 44516, Egypt.
Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Egypt.
Antibiotics (Basel). 2025 Jan 9;14(1):61. doi: 10.3390/antibiotics14010061.
Thermophilic species are among the main culprits behind bacterial gastroenteritis globally and have grown progressively resistant to clinically important antimicrobials. Many studies have been carried out to explore innovative and alternative strategies to control antibiotic-resistant campylobacters in animal reservoirs and human hosts; however, limited studies have been performed to develop efficient control schemes against biofilms.
This study investigated the antimicrobial and antibiofilm activities of some herbal extracts against multidrug-resistant (MDR) species recovered from different sources using phenotypic and molecular techniques.
The overall species prevalence was 21.5%, representing 15.25% and 6.25% for and , respectively. Regarding , the highest resistance rate was observed for amoxicillin-clavulanic acid and colistin (85.25% each), followed by cefotaxime (83.61%) and tetracycline (81.97%), whereas isolates showed absolute resistance to cefotaxime followed by erythromycin (92%) and colistin (88%). Remarkably, all isolates were MDR with elevated multiple antimicrobial resistance (MAR) indices (0.54-1). The antimicrobial potentials of green tea (), rosemary () and ginger () extracts against MDR isolates were assessed by the disk diffusion assay and broth microdilution technique. Green tea extract showed a marked inhibitory effect against tested isolates, exhibiting growth inhibition zone diameters of 8 to 38 mm and a minimum inhibitory concentration (MIC) range of 1.56-3.12 mg/mL, unlike the rosemary and ginger extracts. Our findings reveal a respectable antibiofilm activity (>50% biofilm formation inhibition) of green tea against the preformed biofilms of isolates. Furthermore, real-time quantitative polymerase chain reaction (RT-qPCR) results showed a significant decrease ( < 0.05) in the expression levels of biofilm biosynthesis gene and its regulator ( and , respectively) in isolates treated with the green tea extract in comparison with untreated ones.
This is the first in vitro approach that has documented the inhibitory activity of green tea extract against MDR-biofilm-producing species isolated from different sources. Further in vivo studies in animals' models should be performed to provide evidence of concept for the implementation of this alternative candidate for the mitigation of MDR infections in the future.
嗜热菌是全球细菌性肠胃炎的主要病原体之一，并且对临床上重要的抗菌药物的耐药性日益增强。已经开展了许多研究来探索创新的和替代的策略，以控制动物宿主和人类宿主中耐抗生素的弯曲杆菌；然而，针对生物膜制定有效的控制方案的研究却很有限。
本研究使用表型和分子技术，调查了一些草药提取物对从不同来源分离出的多重耐药（MDR）菌株的抗菌和抗生物膜活性。
总体菌株流行率为21.5%，其中空肠弯曲杆菌和结肠弯曲杆菌分别占15.25%和6.25%。关于空肠弯曲杆菌，阿莫西林-克拉维酸和黏菌素的耐药率最高（均为85.25%），其次是头孢噻肟（83.61%）和四环素（81.97%），而结肠弯曲杆菌分离株对头孢噻肟表现出绝对耐药，其次是红霉素（92%）和黏菌素（88%）。值得注意的是，所有弯曲杆菌分离株均为多重耐药，且多重抗菌耐药（MAR）指数升高（0.54 - 1）。通过纸片扩散法和肉汤微量稀释技术评估了绿茶、迷迭香和生姜提取物对多重耐药弯曲杆菌分离株的抗菌潜力。与迷迭香和生姜提取物不同，绿茶提取物对受试分离株显示出显著的抑制作用，其生长抑制圈直径为8至38毫米，最低抑菌浓度（MIC）范围为1.56 - 3.12毫克/毫升。我们的研究结果表明，绿茶对弯曲杆菌分离株预先形成的生物膜具有可观的抗生物膜活性（生物膜形成抑制率>50%）。此外，实时定量聚合酶链反应（RT-qPCR）结果显示，与未处理的弯曲杆菌分离株相比，用绿茶提取物处理的分离株中生物膜生物合成基因及其调节基因（分别为csgA和csgD）的表达水平显著降低（P<0.05）。
这是首次通过体外方法证明绿茶提取物对从不同来源分离出的产多重耐药生物膜的弯曲杆菌菌株具有抑制活性。未来应在动物模型中进行进一步的体内研究，以提供概念验证证据，以便在未来将这种替代候选物用于减轻多重耐药弯曲杆菌感染。
