This type of resistance requires previous exposure to the drug and would occur over time. One example that is found in health care and causing concern is MRSA or methicillin resistant staphlococcus aureus. Cross resistance occurs as a result of similarity in action of drug groups. Penicillins and cephalosporins are very similar in their chemical structure and action. An organism resistant to a penicillin may have a cross resistance to a cephalosporin because of the similarity in makeup and action.
Microorganisms develop resistance because something alters their structure or function.
The microorganisms have adapted to the drugs. Examine the following list and identify which factors have contributed to the problem of resistance. General assessments, patient teaching and evaluation 2. Specifics for antibacterial agents 3. Specifics for antitubercular agents 4.