Answer:
1. use of the wrong antibiotic
2. use of insufficient concentration of the right antibiotic
Explanation:
MRSA means Methicillin-resistant staphylococcus aureus
VRSA means Vancomycin-resistant Staphylococcus aureus
These are resistant forms of the bacteria <em>Staphylococcus aureus</em> to the antibiotics mentioned.
Bacterial resistance to antibiotics occurs when bacteria develop mechanisms that protect them against the effects of previously effective antibiotics.
Misguided and inappropriate use of antibiotics results in resistance, and they mainly occur as a result of two activities:
1. Use of wrong antibiotics: antibiotics are chosen using a microbiological technique called 'sensitivity testing', to determine which antibiotic is effective against a bacterium. However, when antibiotics are taken without proper sensitivity testing, the bacteria develop resistance against such antibiotics.
2. Use of inadequate concentration of the right antibiotic: This involves using less than the minimum inhibitory of minimum bactericidal concentration of an antibiotic against a bacteria. In this case, the organism has ample time to evolve in the presence of the antibiotic, hence the occurrence of resistance.
