Biofilm and Infection

**135**

expression [3].

**Chapter 9**

**Abstract**

mechanisms in biofilms.

and antibiotic exposure.

**1. Introduction**

Antibiotic Resistance in Biofilm

Biofilms can be found on several living and nonliving surfaces, which are formed by a group of microorganisms, complex assembly of proteins, polysaccharides, and DNAs in an extracellular polymeric matrix. By forming a biofilm, bacteria protect themselves from host defense, disinfectants, and antibiotics. Bacteria inside biofilm are much more resistant to antimicrobial agents than planktonic forms since bacteria that are unresisting to antimicrobial agents in any way can turn resistant after forming a biofilm. Low penetration of antibiotics into the biofilm, slow reproduction, and the existence of adaptive stress response constitute the multiphased defense of the bacterium. This antibiotic resistance, which is provided by biofilm, makes the treatments, which use effective antibiotic doses on the bacterium in planktonic shape, difficult. Biofilm formation potential of bacteria appears as an important virulence factor in ensuring the colonization on the living tissues or medical devices and makes the treatment difficult. The aim of this chapter is to overview the current knowledge of antimicrobial resistance

*Sadık Dincer, Fatima Masume Uslu and Anil Delik*

**Keywords:** biofilm, antibiotic resistance, bacteria, antimicrobial agents

Bacteria can grow in biofilms on a wide variety of surfaces and attach to inert or alive surfaces, including tissues, industrial surfaces, and artificial devices, such as catheters, intrauterine contraceptive devices, and prosthetic medical devices, implants, cardiac valves, dental materials, and contact lenses [1, 2]. Biofilm growth confers several advantages to bacteria, including protective against hostile environments conditions such as osmotic stress, metal toxicity,

Biofilm-associated drug resistance and tolerance play a major role in the pathogenesis of many subacute and chronic bacterial diseases and their recalcitrance to antibiotic treatment, especially in medical device-related infections. The definition of biofilm has been made with the development of new techniques for the direct examination of biofilms over the last four decades. Initially, a biofilm was defined as the composition of bacterial communities bound to coated surfaces in a glycocalyx matrix; subsequently, the correct definition of biofilm was made not only by considering its easily observable properties, such as cells irreversibly attached to a surface or interface embedded in an extracellular polymeric matrix material, but also by taking into account other physiological properties of these organisms such as altered growth rate and different gene
