Bacteria, Viruses, and Antibiotic Resistance: From Gram Stains to TB Therapy | MIT OpenCourseWare

Overview

MIT OpenCourseWare presents a detailed look at bacteria and viruses and the challenges they pose to human health. The lecture emphasizes the scale of infectious disease, the rise of antimicrobial resistance, and the importance of understanding microbial life cycles to counter disease with targeted therapies. It highlights pneumonia, diarrheal diseases, tuberculosis, and the concept of escape pathogens that resist treatment, while also touching on diagnostics and prevention strategies.

Overview

This class provides an in depth look at the microbes that threaten health and the drugs designed to combat them. It begins by framing the burden of infectious disease with examples such as lower respiratory tract infections, diarrheal illness, and tuberculosis, noting the heavy impact in developing regions and the frequent co infection with HIV in the case of TB. The lecture then shifts to the biology of bacteria and viruses and how their lifecycles determine therapeutic strategies, including the molecular targets of antibiotics and antivirals and how resistance emerges.

Microbes and Diseases

The speaker reviews common bacterial pathogens associated with pneumonia such as Streptococcus pneumoniae and Klebsiella pneumoniae, and notes other culprits like Staphylococcus aureus. Diarrheal diseases are attributed to organisms such as Campylobacter jejuni and Salmonella enterica, while Helicobacter pylori demonstrates the link between infection, ulcer disease and cancer risk. The talk also covers sexually transmitted infections caused by Neisseria species and the broad category of mycobacterial infections led by Mycobacterium tuberculosis, historically known as consumption.

Antibiotics and Resistance

The course explains how antibiotics disrupt essential bacterial processes including cell wall biosynthesis, DNA replication, protein synthesis, and folate metabolism. It describes penicillin as one of the first antibiotics and demonstrates how bacterial resistance quickly emerges through mechanisms like beta lactamases and modifications that prevent drug binding. The discussion covers vancomycin resistance and the broader issue of multidrug resistance, including the escape pathogens such as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and certain Enterobacter species.

Diagnostics and Treatment

Historical Context and Look Ahead

The lecturer recounts the discovery of penicillin and the rise of antibiotic resistance as an ongoing arms race. A visual demonstration of resistance development on plates underscores how quickly susceptibility can be lost. The session closes by previewing resistance mechanisms and the upcoming discussion on viral resistance to antivirals, underscoring the need for continued research, surveillance, and innovation.