Nayak Niranjan, Satpathy Gita, Prasad Sujata, Thakar Alok, Chandra Mahesh, Nag T C
Department of Ocular Microbiology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
Department of Microbiology, Manipal College of Medical Sciences, Pokhara, Nepal.
BMC Ophthalmol. 2016 Sep 21;16(1):165. doi: 10.1186/s12886-016-0340-z.
Discovery of sessile mode of microbial existence (Biofilm state) focussed much interest, during the recent years, on the study of biofilms in many recurring and chronic infections. However, the exact role of microbial biofilms in chronic rhinosinusitis and orbital cellulitis were not elucidated earlier. The purpose of the present study was to look for the adherent property and biofilm producing ability of the clinical isolates in chronic rhinosinusitis and orbital cellulitis, and to look for the effects of antimicrobial agents on these biofilms by colorimetric assay and ultrastructural analysis.
Organisms were isolated and identified from various clinical samples in patients with chronic sinusitis and orbital cellulitis. Antimicrobial sensitivity testing was carried out by the standard protocol. Biofilms were developed; quantified and antimicrobial drug perfusion through the biofilm model was evaluated by the earlier devised procedure. Electronmicroscopic study of the biofilm was performed by the recommended technique.
Of the total of 70 clinical samples processed, 48 i.e. 68.5 % grew bacteria and 13 i.e.(18.6 %) fungi. Staphylococcus aureus (20), S epidermidis (16) and Pseudomonas aeruginosa (6) accounted for the majority of the bacterial isolates. Aspergillus flavus (8), however was the commonest amongst the fungi. A total of 40 bacteria and 8 fungi could be tested for biofilm production. Eighteen (45 %) of the 40 bacterial isolates and 4(50 %) out of the 8 A flavus isolates were found to be biofilm producers. In vitro adherence testing revealed that majority i.e. 16 (88.8 %) of the 18 biofilm positive bacteria were adherent to artificial surfaces. Antimicrobial drug perfusion through the biofilm model was poor. Antimicrobial treatment was totally ineffective against strong biofilm producers, whose electron microscopic picture was quite similar to that observed for biofilm producers without any antimicrobial pre-treatment.
Filamentous fungi, like bacteria were capable of forming biofilms, which could be one of the important virulence factors in determining the pathogenic potential of these organisms in causing chronic rhinosinusitis and orbital cellulitis.
近年来，微生物固着生存模式（生物膜状态）的发现引发了人们对许多复发性和慢性感染中生物膜研究的浓厚兴趣。然而，微生物生物膜在慢性鼻窦炎和眼眶蜂窝织炎中的确切作用此前尚未阐明。本研究的目的是探寻慢性鼻窦炎和眼眶蜂窝织炎临床分离株的黏附特性和生物膜形成能力，并通过比色法和超微结构分析来研究抗菌药物对这些生物膜的影响。
从慢性鼻窦炎和眼眶蜂窝织炎患者的各种临床样本中分离并鉴定微生物。按照标准方案进行抗菌药物敏感性测试。培养生物膜；通过先前设计的程序对生物膜进行定量并评估抗菌药物通过生物膜模型的灌注情况。采用推荐技术对生物膜进行电子显微镜研究。
在总共处理的70份临床样本中，48份（即68.5%）培养出细菌，13份（即18.6%）培养出真菌。金黄色葡萄球菌（20株）、表皮葡萄球菌（16株）和铜绿假单胞菌（6株）占细菌分离株的大多数。然而，黄曲霉（8株）是真菌中最常见的。总共对40株细菌和8株真菌进行了生物膜形成测试。40株细菌分离株中有18株（45%）以及8株黄曲霉菌株中有4株（50%）被发现是生物膜形成菌。体外黏附测试显示，18株生物膜阳性细菌中的大多数，即16株（88.8%）能黏附于人工表面。抗菌药物通过生物膜模型的灌注效果不佳。抗菌治疗对强生物膜形成菌完全无效，其电子显微镜图像与未经任何抗菌预处理的生物膜形成菌的图像非常相似。
丝状真菌与细菌一样能够形成生物膜，这可能是决定这些微生物引起慢性鼻窦炎和眼眶蜂窝织炎致病潜力的重要毒力因素之一。
