El-Soudany Ingy, Attia Nancy, Emad Rasha, Rezk Shahinda
Microbiology and Immunology Department, Pharos University in Alexandria, Alexandria, Egypt.
Microbiology Department, Medical Research Institute, Alexandria University, Alexandria, Egypt.
Med Princ Pract. 2024;33(3):281-290. doi: 10.1159/000537852. Epub 2024 Feb 15.
Acinetobacter baumannii (A. baumannii) is an opportunistic bacterium with multiple virulence factors, including capsule and biofilm, and is known for its high drug resistance. Anti-virulence natural substances have been suggested as novel alternatives to conventional antibiotics. We aimed to evaluate the effect of citric and ascorbic acids as anti-biofilm and anti-capsular agents against multidrug-resistant (MDR) A. baumannii clinical isolates.
Twenty-eight A. baumannii MDR isolates were collected from different clinical sources. The minimum inhibitory concentration (MIC) of each agent was estimated. Biofilm formation and capsule were investigated phenotypically in the absence and presence of both agents at ½ and ¼ MICs. The presence of 14 adhesive and nonadhesive virulence genes was investigated.
Phenotypically, all the isolates were biofilm producers and were capsulated. The MIC of citric acid ranged from 1.25 to 2.5 mg/mL, while that of ascorbic acid was 3 mg/mL for all isolates. Both agents showed significant reduction in biofilm and capsular thinning. Ascorbic acid showed a dose-dependent effect in both biofilm reduction and capsule thinning unlike citric acid. Four genes, papG23, sfa1, fyuA, and cvaC, were absent among all isolates, while iutA was present in 100% of isolates. Other genes showed different distributions among the isolates. These virulence genes were not correlated to the anti-biofilm effect of both agents. Ascorbic acid was observed to have a better effect than citric acid. This can provide a clue for a better treatment regimen including ascorbic acid against MDR A. baumannii infections.
鲍曼不动杆菌是一种具有多种毒力因子（包括荚膜和生物膜）的机会致病菌，以其高耐药性而闻名。抗毒力天然物质已被提议作为传统抗生素的新型替代品。我们旨在评估柠檬酸和抗坏血酸作为抗生物膜和抗荚膜剂对多重耐药（MDR）鲍曼不动杆菌临床分离株的作用。
从不同临床来源收集了28株鲍曼不动杆菌MDR分离株。估计每种药物的最低抑菌浓度（MIC）。在不存在和存在两种药物（分别为½ MIC和¼ MIC）的情况下，对生物膜形成和荚膜进行表型研究。研究了14种黏附性和非黏附性毒力基因的存在情况。
表型上，所有分离株均为生物膜产生菌且具有荚膜。柠檬酸的MIC范围为1.25至2.5 mg/mL，而所有分离株的抗坏血酸MIC均为3 mg/mL。两种药物均显示生物膜显著减少和荚膜变薄。与柠檬酸不同，抗坏血酸在生物膜减少和荚膜变薄方面均显示出剂量依赖性效应。所有分离株中均不存在四种基因，即papG23、sfa1、fyuA和cvaC，而iutA在100%的分离株中存在。其他基因在分离株中的分布不同。这些毒力基因与两种药物的抗生物膜作用无关。观察到抗坏血酸的效果优于柠檬酸。这可为包括抗坏血酸在内的更好治疗方案对抗MDR鲍曼不动杆菌感染提供线索。
