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IMPACT OF BIOFILM ON HEALING AND A METHOD FOR IDENTIFYING IT IN THE WOUND
JASENKA ŠKRLIN
; Centar za kliničku mikrobiologiju i bolničke infekcije, Klinička bolnica Dubrava, Zagreb, Hrvatska
Sažetak
The skin microbiome is the aggregate of microorganisms that reside on the surface and in deep layers of the skin. Skin is colonized by bacteria, fungi, viruses and mites, maintaining a balance. Disruption in the ecosystem results in skin infections. Chronic wounds in diabetics, elderly and immobile individuals are at risk of skin organisms to invade and become pathogenic upon breach of the skin barrier. The bacteria of the skin microbiome may contribute to delayed healing and persistent infl ammation. Staphylococcus epidermidis is an invasive skin organism that causes infection, i.e. hospital acquired infection (HAI) on medical devices and form biofi lm. At the most basic level, biofi lm can be described as bacteria embedded in a thick, slimy barrier of sugars and proteins. The biofi lm barrier protects the microorganisms from external threats. Biofi lms provide a reservoir of potentially infectious microorganisms that are resistant to antimicrobial agents, and their importance in the failure of medical devices and chronic infl ammatory condition is increasingly being
recognized. Particular research interest exists in the association of biofi lms with wound infection and non-healing, i.e. chronic wounds. There is now strong evidence that biofi lm is present in the majority of chronic wounds. Specialized microscopic techniques used since 2008 have allowed several research groups to demonstrate that 60% to 90% of chronic wounds have biofilm versus only 6% of acute wounds. While many studies confirm that chronic wounds often contain a polymicrobial flora, controversy remains with regard to whether these organisms directly contribute to non-healing. It seems most likely that individual bacteria themselves are no direct correlation between the presence of four or more distinct bacterial species in a wound and non-healing, suggesting that mixed microbial populations are the cause of pathology. The most reliable method to confirm the presence of a biofilm is specialized microscopy, e.g., bright-fi eld, fl uorescence in situ hybridization (FISH), and environmental scanning electron
microscope (ESEM). Surface wound cultures underestimate total wound microbiota – misleading. Histological staining of deep debrided tissue shows evidence of biofi lms. Now it is recognized that the majority of microbial species in chronic wounds are anaerobic bacteria (deep swabbing techniques yield similar fi ndings to biopsies) if samples are processed within two hours. Traditional (wound culture method) cultures have limitations because all microbes (the organisms within the biofi lm) cannot be isolated in culture or cannot be detected. Therefore, the most effective methods are molecular
analyses. Newer methods using microbial DNA may help decipher the role the microbes play in infection and critical colonization and provide quantitative and qualitative information on the range of microorganisms, including bacteria and biofilm formation.
Ključne riječi
bacteria; biofilm; chronic infections; diagnosis
Hrčak ID:
155188
URI
Datum izdavanja:
5.4.2016.
Posjeta: 2.318 *