Final answer:
Resistant bacteria can inactivate beta-lactam antibiotics using beta-lactamase, alter the drug's target through mutations, prevent drug entry, or expel the drug using efflux pumps. Horizontal gene transfer plays a vital role in spreading resistance. Misuse and overuse of antibiotics exacerbate the problem, posing a severe public health concern.
Step-by-step explanation:
The differences between bacteria that are resistant to beta-lactam antibiotics and those that are susceptible to these antibiotics are multifaceted. Resistant bacteria can degrade or modify the antibiotic, preventing its action. An example is the production of beta-lactamase enzymes that inactivate penicillin and related drugs by breaking the beta-lactam ring, a structure central to their antibacterial activity.
Bacteria may also undergo genetic mutations that alter the drug's target, such as mutating parts of the ribosome to avoid the binding of antibiotics that disrupt protein synthesis. Another resistance mechanism is the reduction of drug entry into the bacterial cell, exemplified by the waxy cell envelope of Mycobacterium species. Finally, the use of efflux pumps can remove antibiotics from the cell, sometimes via multidrug-resistance efflux pumps (MDR pumps), which can expel a wide range of drugs.
Bacteria acquire resistance through various genetic mechanisms, including spontaneous mutation and horizontal gene transfer, which can occur through transformation, conjugation, or transduction. In the clinical setting, the propagation of resistant bacteria is exacerbated by the misuse and overuse of antibiotics, incomplete treatment courses by patients, and the lack of development of new drugs to combat resistant strains.
This resistance leads to a significant public health issue, where once-treatable infections become challenging or impossible to cure, leading to increased morbidity, mortality, and healthcare costs.