Importance Of Antibiotic Resistance

NANOPARTICLES TO INHIBIT ANTIBIOTIC RESISTANT Pseudomonas aeruginosa

Chapter 1 Introduction

1.1 Antibiotics and Resistance

One of the greatest blessings of mankind is the discovery of antibiotics against various pathogenic bacteria. However important side effects of the use of antibiotics are the development of resistance by the targeted pathogens. The irrational use of antibiotics has led to the rapid development of antibiotic resistance in pathogens. The discovery and clinical use of many antibiotics has been paralleled by the emergence of bacteria that resist their action. Several factors are responsible for drug resistance in bacteria like self-medication and noncompliance with recommended treatments, availability of antibiotics like other

Resistance also can be minimized by combining two unrelated chemotherapeutic agents because it is likely that mutant strain resistant to one antibiotic will also be sensitive to another. But with increasing prevalence of resistant genes multiple antibiotic therapies is proving less attractive as a clinical useful strategy. The development of antimicrobial resistance may be caused by (a) alteration or inactivation of the drug; (b) reduced binding capacity of the drug due to alteration in the binding sites; (c) reduction in the antimicrobial effect due to modification of the metabolic pathways; or (d) decreased permeability and/or increased active flux leading to reduced intracellular accumulation of antimicrobial agents [Li XZ et al 2009]. However, antimicrobial resistance may be intrinsic or acquired; it can develop through the mutation of existing genes [Lock RL, Harry EJ.2008, McNulty CA et al 2007 ], or through the transfer of genes from other species or strains [Mouton JW.1999, Ochiai, K.et al

In many cases parameters such as solubility and affinity can be changed by altering chemical structures without altering the site of drug action. The new compounds can be more potent than the parent compound because resistance is based on structural recognition. However the resistance has developed for new analogues and these altered compounds have become less useful over a period of time.

New classes of antimicrobial compounds on the other hand are much more difficult to identify. They must be isolated from natural sources or synthetically designed to interact with specific microbial structures and then screened for efficiency and toxicity.

To be effective new antimicrobial compounds must work at novel sites in bacterial metabolism and biosynthesis or to be structurally dissimilar to existing compounds, thus avoiding resistance factors. At present naturally occurring compounds which are structurally and functionally unique are the choice of antimicrobial agents to treat drug resistant pathogens. As it is known, application of more powerful antibiotics can lead to limited and temporary advances and eventually contribute to developing greater resistance. Resources against multidrug-resistant pathogenic infections are now