Certification Board of Infection Control and Epidemiology (CBIC) Practice Exam 2025 - Free CBIC Practice Questions and Study Guide

Methicillin-resistant Staphylococcus aureus (MRSA) is well-known for its antibiotic resistance, particularly to methicillin and other beta-lactam antibiotics, which include penicillins and cephalosporins. This resistance is due to the acquisition of the mecA gene, which codes for a penicillin-binding protein that has a low affinity for beta-lactam antibiotics, rendering these drugs ineffective. Consequently, treating MRSA infections often requires the use of more potent antibiotics, such as vancomycin or linezolid, which may not be commonly employed for treating non-resistant strains of Staphylococcus aureus.

The other organisms listed may exhibit antibiotic resistance, but none are as broadly associated with a specific, well-understood, and significant resistance mechanism as MRSA. For example, while Escherichia coli can also be resistant to multiple antibiotics, especially in the context of urinary tract infections or hospital-acquired infections, it does not have the same notorious reputation for resistance as MRSA. Similarly, Streptococcus pneumoniae and Haemophilus influenzae can develop resistance, particularly to penicillin, but they are generally not recognized to the same extent in the context of public health discussions on antibiotic resistance as MRSA is