Bacterial resistance is the capacity of bacteria to withstand the effects of antibiotics or biocides that are intended to kill or control them .Bacteria may manifest resistance to antibacterial drugs through a variety of mechanisms.
Some species of bacteria are innately resistant to 1 class of antimicrobial agents.In such cases, all strains of that bacterial species are likewise resistant to all the members of those antibacterial classes.Of greater concern are cases of acquired resistance, where bacteria become resistant to an antibacterial agent andproliferates and spreads under the selective pressure of use of that agent.

There are Several mechanisms of acquired antimicrobial resistance :
First, the organism may acquire genes encoding enzymes, such as B-lactamases, that destroy the
antibacterial agent before it can have an effect.
Second, bacteria may acquire efflux pumps that extrude the antibacterial agent from the cell before it can reach its target site .
Third, bacteria may acquire several genes for a metabolic pathway which ultimately produces
altered bacterial cell walls that no longer contain the binding site of the antimicrobial agent .

What is the Dangers of Antibiotic Resistance ?
Resistant bacteria can cause everything from a skin infection to sinusitis to of the most dangers of it is increasing amputation .Last year, antibiotic resistant infections killed 25,000 people in Europe, the Guardian reports.
One of the causes of the antibiotic resistance is inappropriate use of antibiotics.The problem is that every time antibiotics are used, some bacteria survive, giving rise to dangerous new strains like MRSA and CRKP.
Antibiotics are effective against bacteria, not viruses and their use against colds or influenza has contributed to the increased bacterial resistance.If the case of sinusitis or pneumonia is determined to be bacterial, then it should be considered whether or not the condition is severe enough to warrant antibiotics.Taking more care with the use of antibiotics is one step we can take towards controlling antibiotic resistant bacteria but still research needs to be done on new and old methods for fighting bacterial infection.