Thakur Vipasha, Chalana Anandita, Gupta Anvita, Kaur Indu Pal, Sharma Prince, Capalash Neena
Department of Biotechnology, Panjab University, Chandigarh, 160014, India.
AINovoBiotech Inc., 3299 Ramos Circle, Sacramento, CA 95827, United States.
J Appl Microbiol. 2025 Jul 1;136(7). doi: 10.1093/jambio/lxaf171.
Co-infections by MDR Acinetobacter baumannii and Klebsiella pneumoniae pose daunting challenges in healthcare settings. This study aimed at investigating the biofilm formation potential of their co-culture and evaluating the effect of combination therapy.
Spatial distribution of A. baumannii and K. pneumoniae in co-cultured biofilm was analysed by Confocal Laser Scanning Microscopy (CLSM) with Green Fluorescent Protein (GFP) and mCherry-tagged strains and Field Emission Scanning Electron Microscopy (FESEM). The antibiotic combination was selected through checkerboard assay and its antibiofilm activity was assessed against the co-culture of MDR strains.
Cell-free supernatant of K. pneumoniae enhanced the planktonic and biofilm growth of A. baumannii. Co-culture of these pathogens revealed interspersed growth in close proximity and significantly higher biofilm than their monocultures (P-value < 0.01). Synergistic combination of colistin (MIC/8) and rifamycin (MIC/4) at Fractional Inhibitory Concentration (FIC) killed both the pathogens in monoculture within 3 h. However, the co-culture exhibited enhanced resistance requiring 24 h for complete eradication. Biofilm formation was inhibited by 77% at 2 × FIC. Whereas the preformed biofilm was eradicated by 40% at 3 × FIC (1/4th of minimum biofilm eradication concentration). CLSM confirmed structural disruption of the biofilm matrix post-treatment at 3 × FIC, with reduction in biofilm thickness from 7 to 4 µm.
Acinetobacter baumannii and K. pneumoniae co-exist harmoniously, forming enhanced biofilms in co-cultures. Colistin-rifamycin combination proved highly effective against these dual-species biofilms.
耐多药鲍曼不动杆菌和肺炎克雷伯菌的合并感染给医疗机构带来了严峻挑战。本研究旨在调查它们共培养时形成生物膜的潜力，并评估联合治疗的效果。
通过共聚焦激光扫描显微镜（CLSM），使用绿色荧光蛋白（GFP）和mCherry标记菌株，以及场发射扫描电子显微镜（FESEM）分析共培养生物膜中鲍曼不动杆菌和肺炎克雷伯菌的空间分布。通过棋盘法选择抗生素组合，并评估其对耐多药菌株共培养物的抗生物膜活性。
肺炎克雷伯菌的无细胞上清液促进了鲍曼不动杆菌的浮游生长和生物膜生长。这些病原体的共培养显示出紧密相邻的散在生长，并且生物膜比它们的单培养物显著更高（P值<0.01）。在分数抑菌浓度（FIC）下，黏菌素（MIC/8）和利福霉素（MIC/4）的协同组合在3小时内杀死了单培养物中的两种病原体。然而，共培养物表现出增强的耐药性，需要24小时才能完全根除。在2×FIC时生物膜形成被抑制了77%。而在3×FIC（最低生物膜根除浓度的1/4）时，预先形成的生物膜被根除了40%。CLSM证实，在3×FIC处理后生物膜基质的结构被破坏，生物膜厚度从7μm减少到4μm。
鲍曼不动杆菌和肺炎克雷伯菌和谐共存，在共培养中形成增强的生物膜。黏菌素-利福霉素组合对这些双物种生物膜证明非常有效。
