Background: In the past years, saprophytic bacteria and candida have been emerging as potential human pathogens causing life-threatening infections in patients with cancer. This study was designed to determine the bacteria and candida species, causing bloodstream infections in cancer patients and the assessment of their susceptibility to antibiotics and biosynthesised silver nanoparticles. Materials and Methods: Ninety-seven microbial pathogens recovered from blood samples of cancer patients were included in the present study. The microbial isolates were collected in a duration period extending from December 2016 to July 2018 at National Cancer Institute, Cairo, Egypt. The clinical samples were collected using microbiological methods and were cultivated on MacConkey agar, blood agar media and Sabouraud dextrose agar media. The microbial isolates were identified using both standard microbiological methods and VITEK 2 compact automated system. The antibiotic resistance pattern was determined by the VITEK 2 compact automatic system and disk diffusion method, according to the Clinical and Laboratory Standards Institute. The characterisation of nanoparticles was carried out using ultraviolet spectroscopy and electron microscope. The antimicrobial activity of bio (AgNPs) was evaluated. Results: A total of 97 microbial isolates recovered from collected blood samples from cancer patients were included in the study. Pathogenic bacteria and Candida were represented by 74 isolates (76.22%) and 23 isolates (23.69), respectively. Among the 74 bacterial isolates, Escherichia coli constituted (27.81%), Klebsiella pneumoniae (24.72%), Acinetobacter baummannii (11.33%), Pseudomonas aeruginosa (4.12%), Enterobacter spp. (3.09%) and) Staphylococcus aureus (2.06%). Cedecea davisae (1.03%), Burkholderia cepacia (1.03%) and Pantoea agglomerans (1.03%). Among the 23 Candida isolates, Candida tropicalis constituted (9.27%), Candida albicans (5.15%), Candida glabrata (5.15%) and Candida krusei (4.12%) from the total microbial isolates. The antibiotic susceptibility results revealed that amikacin and gentamycin were the most effective antibiotics against Gram-negative bacteria, while vancomycin and linezolid were most effective against S. aureus. Caspofungin was the most effective against candida species. The obtained stable biosynthesised silver nanoparticles ranged in size from 10 nm to 100 nm and were mostly spherical in shape. These biosilver nanoparticles showed the highest antimicrobial activity against most of the microbial isolates (bacteria and Candida). The in vitro cytotoxicity of biosynthesised AgNPs on HeLa cell lines revealed a dose-dependent potential. The IC50 value of AgNPs was found 6 and 5.6 μg/ml, respectively. Conclusion: The present study revealed a significant distribution of multidrug-resistant microbes, which may increase the burden of healthcare to prevent infections in cancer patients. Biosilver nanoparticles exhibit antimicrobial activity against multidrug-resistant microbes and could be considered as effective agents against these strains.


中文翻译：

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生物合成银纳米颗粒对从患有菌血症和念珠菌血症的癌症患者中分离出的多重耐药微生物的抗菌活性



背景：在过去的几年中，腐生细菌和念珠菌已成为潜在的人类病原体，导致癌症患者出现危及生命的感染。这项研究旨在确定引起癌症患者血流感染的细菌和念珠菌种类，并评估他们对抗生素和生物合成银纳米颗粒的敏感性。材料和方法：本研究包括从癌症患者的血液样本中回收的 97 种微生物病原体。微生物分离株是在 2016 年 12 月至 2018 年 7 月期间在埃及开罗国家癌症研究所收集的。使用微生物学方法收集临床样品并在麦康凯琼脂、血琼脂培养基和沙氏葡萄糖琼脂培养基上培养。使用标准微生物学方法和 VITEK 2 紧凑型自动化系统对微生物分离株进行鉴定。根据临床和实验室标准研究所的说法，抗生素耐药性模式是通过 VITEK 2 紧凑型自动系统和纸片扩散法测定的。使用紫外光谱和电子显微镜对纳米粒子进行了表征。评估了生物（AgNPs）的抗菌活性。结果：该研究共纳入了从癌症患者血液样本中回收的 97 种微生物分离株。致病菌为74株（76.22%），念珠菌为23株（23.69%）。 74株细菌中，大肠杆菌占27.81%，肺炎克雷伯菌占24.72%，鲍曼不动杆菌占11%。33%)、铜绿假单胞菌(4.12%)、肠杆菌属。 (3.09%) 和)金黄色葡萄球菌(2.06%)。 Cedecea davisae (1.03%)、洋葱伯克霍尔德菌(1.03%) 和成团泛菌(1.03%)。在23个念珠菌分离株中，热带念珠菌占微生物总数的9.27%，白色念珠菌占5.15%，光滑念珠菌占5.15%，克柔念珠菌占4.12%。药敏结果显示，阿米卡星和庆大霉素对革兰氏阴性菌最有效，万古霉素和利奈唑胺对金黄色葡萄球菌最有效。卡泊芬净对念珠菌最有效。获得的稳定的生物合成银纳米颗粒尺寸范围为10 nm至100 nm，且形状大多为球形。这些生物银纳米颗粒对大多数微生物分离株（细菌和念珠菌）表现出最高的抗菌活性。生物合成的 AgNP 对 HeLa 细胞系的体外细胞毒性显示出剂量依赖性潜力。 AgNPs 的 IC50 值分别为 6 和 5.6 μg/ml。结论：本研究揭示了多重耐药微生物的显着分布，这可能会增加癌症患者预防感染的医疗负担。生物银纳米颗粒对多重耐药微生物表现出抗菌活性，可被认为是对抗这些菌株的有效药物。