Bacterial biofilms with emphasis on coagulase-negative staphylococci

Abstract

In addition to their capacity to attach to surfaces, various groups of microorganisms also produce an extracellular polymeric substance known as "slime". This slime forms a thin layer around cells known as biofilm. Thus, biofilm structure comprises bacterial cells and an extracellular polymeric substance. It also presents a defined architecture, providing the microorganisms with an excellent protective environment and favoring the exchange of genetic material between cells as well as intercellular communication. The ability to produce biofilm is observed in a large group of bacteria, including coagulase-negative staphylococci (CNS) which are the predominant microorganisms of normal skin flora and have been implicated as the causative agents of hospital infections. Bacteremia caused by these agents is common in immunodepressed persons, in patients with cancer, in adult and neonatal intensive care units (ICU) and in patients using catheters or other prosthetic devices. The pathogenicity of CNS infections is probably related to the production of slime, which adheres preferentially to plastic and smooth surfaces, forming a biofilm that protects against attacks from the immune system and against antibiotic treatment, a fact hindering the eradication of these infections. The main objective of the present review was to describe basic and genetic aspects of biofilm formation and methods for its detection, with emphasis on biofilm creation by CNS and its relationship with diseases caused by these microorganisms which are becoming increasingly more frequent in the hospital environment.

Coagulase Negative Staphylococci as an emerging cause of bovine mastitis: prevalence, antimicrobial resistance and biofilm formation

“…epidermidis was the most species forming biofilms compared to other CNS species. The same was reported by Oliveira and Cunha (2008) and Simojoki et al (2012). While, Rumi et al (2013) disagreed as S. chromogenes was the most predominant in their work.…”

Biofilms: Microbial Cities of Scientific Significance

“…These extra polymeric enclosures not only favor the microorganisms by providing the essential nutrients but also create a favorable environmental condition for their survival and offers architectural integrity [14]. In addition, it enables genetic transfer and intracellular communication.…”

“…These water channels allow the flow of nutrients, oxygen and microorganisms from one site to other through fluid circulation and they also maintain the hydrated condition which provides a natural environment for the survival of the enclosed microbial community. Biofilms are highly intricate and are usually heterogeneous in nature which comprises of thin base deposits ranging from monolayer to several layers of cells consisting of water channels [14]. The type of organism also influences the structure of biofilms.…”

Production of Slime Layer by Staphylococcus epidermidisIsolated From Corneal Infection

“…The results are similar to those reported by other authors [12], who found that slime layer and multi drug resistance were the important virulence factors of S. epidermidis in bacterial keratitis. Studies on biofilms have shown that S. epidermidis is the most frequently isolated slime-producing CNS and is also the most common cause of nosocomial infections in patients with catheters, medical implants or other invasive devices [13].…”