MRSA has emerged as a serious infectious disease, with the first case of methicillin-resistant S. aureus being detected in 1961. Why are medical professionals so concerned when antibiotics exist that can kill MRSA?

MRSA can transfer methicillin-resistance to other bacteria.

Patients are not treated with correct antibiotics rapidly enough to prevent serious illness.

MRSA could acquire additional antibiotic resistance genes from other bacteria to become a "super bug."

All of the above.

All of the options are true for a MRSA infection.

Explanation:

Staphylococcus aureus is one of the most frequent pathogens causing hospital and community infections. S. aureus can become very easy methicillin resistant (called MRSA isolates) and others beta-lactam antibiotics (are the ones widely used to treat infections) and usually can be resistant to other class of antibiotics, become a very strong bacteria making treatment options very limited. MRSA isolates can rapidly transfer the methicillin resistance to other species of Staphylococcus and some other bacteria. Also S. aureus can acquire other antibiotic resistant genes making a deadly bacterium for its strong resistance. It is in search how the bacterium acquire this antibiotics resistance (and other virulence factors genes) and the mechanism involve to develop new drugs to treat MRSA infections with the hope that can't develop resistance to this new drugs.