Mechanisms of Antibiotic Resistance


At the end of this CU students should be able to:
1. Know the mode of action of the main classes of antibiotics and possible mechanisms of resistance.
2. Understand the action of antibiotics at the intracellular level.
3. Know the main examples of bacteria resistant to antibiotics, at hospital level and in the community.
4. Interpret laboratory data from antibiotic susceptibility tests.
5. Design and execute laboratory protocols to determine the mechanism (s) of resistance to a given antibiotic.

General characterization





Responsible teacher

Isabel Couto


Weekly - Se a UC for oferecida como opcional, o horário será disponibilizado no 2º semestre

Total - 24

Teaching language



Not applicable


• Davies J. and Davies D (2010). Origins and Evolution of Antibiotic Resistance. Microbiol. Mol. Biol. Rev., 74(3):417-433.
• de Sousa JCF and Peixe LV (2010) Antibióticos Antibacterianos. In Microbiologia, pp453-469, WF Canas Ferreira, JCF de Sousa, N Lima (ed). Lidel.
• ECDC/EMEA JOINT TECHNICAL REPORT (2009) The bacterial challenge: time to react. European Centre for Disease Prevention and Control, ISBN 978-92-9193-193-4 doi: 10.2900/2518.
• Livermore DM (2012). Fourteen years in resistance (review). Int. J. Antimicrob. Agents. 39: 283– 294.
• Magiorakos A.-P. et al. (2012) Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect; 18: 268–281.
• Theuretzbacher, U (2012) Accelerating resistance, inadequate antibacterial drug pipelines and international responses (review). Int. J. Antimicrob. Agents. 39: 295– 299.

Teaching method

Theoretical classes based on the presentation of slides. Laboratory classes, in which each group of students (maximum 2 students/group) will receive a set of strains for which they must determine the phenotype (susceptibility vs resistance) for various antibiotics and in cases of resistance, design and carry out laboratory experiments that will to determine the possible mechanism(s) that explain this resistance.

Evaluation method

Students will be assessed through a written exam with multiple choice questions, focusing on the contents of the theoretical classes (70% of the final grade) and by the presentation and discussion of the “case study” (30% of the final grade), on a scale of classification from 0 to 20 values. Students with a classification equal to or higher than 9.5 will be approved in the two components evaluated (theoretical exam and presentation of the “case study”).

Subject matter

Theoretical component:
1. Resistance to antibiotics in the 21st century.
2. Susceptibility vs. resistance. Minimum inhibitory concentration and minimum bactericidal concentration; definition of “breakpoint”.
3. Main mechanisms of antibiotic resistance in bacteria.
4. Bacteria resistant to antibiotics: most relevant examples at the hospital and community level. Staphylococcus aureus resistant to methicillin (MRSA) and vancomycin (VISA / VRSA); Vancomycin-resistant Enterococcus (VRE), Penicillin-resistant (PRP) Streptococcus pneumonia, Mycobacterium tuberculosis multi/extensively resistant (M / XDR-TB), Gram-negative bacteria producing ESBLs and carbapenemases.
5. Action of antibiotics at the intracellular level.
Practical component:
Experimental resolution of case-studies. Determination of antibiotic resistance mechanisms in Escherichia coli and Staphylococcus aureus isolates.


Programs where the course is taught: