Department of Microbiology, Faculty of Medical Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka.
Department of Basic Sciences, Faculty of Allied Health Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka.
Lett Appl Microbiol. 2021 Oct;73(4):477-485. doi: 10.1111/lam.13532. Epub 2021 Jul 20.
Biofilms have been associated with chronic wound infections in diabetic patients. The study assessed the occurrence of biofilms in chronic diabetic wounds (CDWs) in a Sri Lankan cohort. Tissue specimens collected during surgical debridement were analysed by quantitative differential viable counting, scanning electron microscopy (SEM), fluorescence insitu hybridization (FISH) and light microscopy with Gram and Haematoxylin-Eosin staining. All specimens harboured >5·0 log CFU per g bacteria and 2-9 distinct species per specimen were recovered from twenty wounds by culture. The most frequently isolated bacterium was Pseudomonas spp. (12/20;60%). Strict anaerobes were isolated from 10/20 specimens. Gram and Haematoxylin-Eosin staining showed aggregated micro-colonies, embedded in the wound tissue bed (20/20) but the exopolymer matrix was not visible in all samples (13/20). Fluorescence microscopy using a eubacteria-specific FISH probe indicated the presence of bacterial aggregates within the deep layers of the wound tissues (20/20). SEM revealed the presumptive architecture of matrix-embedded microbial clusters (20/20). The approximate diameter of bacterial aggregates in tissues ranged between 12 and 400 µm. Bacterial infiltration into the internal portions of the tissues was apparent using FISH, Gram, and Haematoxylin-Eosin staining. All CDWs carried biofilm-specific morphological features. FISH was more specific than SEM and indicated the presence of microcolonies within deeper tissues.
生物膜与糖尿病患者的慢性伤口感染有关。本研究评估了斯里兰卡队列中慢性糖尿病伤口（CDW）中生物膜的发生情况。通过定量差异活菌计数、扫描电子显微镜（SEM）、荧光原位杂交（FISH）和革兰氏染色和苏木精-伊红染色的光学显微镜分析在手术清创过程中收集的组织标本。所有标本均含有>5.0 log CFU/g 细菌，从 20 个伤口中通过培养回收了 2-9 种不同的物种。最常分离的细菌是假单胞菌属（12/20；60%）。从 10/20 个标本中分离出严格厌氧菌。革兰氏染色和苏木精-伊红染色显示聚集的微菌落，嵌入伤口组织床中（20/20），但并非所有样本中都可见到胞外聚合物基质（13/20）。使用细菌特异性 FISH 探针的荧光显微镜表明，在伤口组织深层存在细菌聚集物（20/20）。SEM 揭示了基质嵌入微生物簇的假定结构（20/20）。组织中细菌聚集体的近似直径在 12 和 400 µm 之间。使用 FISH、革兰氏染色和苏木精-伊红染色可以明显看出细菌渗透到组织的内部。所有 CDW 都具有生物膜特有的形态特征。FISH 比 SEM 更具特异性，并表明在更深的组织中存在微菌落。
