Microbiology Introduction Lecture Notes PDF, Wits BCMH 2025

Microbiology: Introduction Prof Nazir Ahmed Ismail HoD: Clinical Microbiology & Infectious Diseases [email protected] BCMH 2025 Objectives Understand the scope, curriculum outline and expectations for Microbiology Understand t...

Microbiology: Introduction Prof Nazir Ahmed Ismail HoD: Clinical Microbiology & Infectious Diseases [email protected] BCMH 2025 Objectives Understand the scope, curriculum outline and expectations for Microbiology Understand the importance of infectious diseases and microbiology for medical doctors Provide a simple classification scheme of the microbial world Explain the common modes of transmission of infections Classify bacteria according to morphology, aero tolerance and Gram stain reaction Draw an annotated diagram of a typical bacterial cell Compare and contrast similarities and differences between the Gram-positive and Gram-negative bacterial cell walls List the sub-classification of Gram-positive and Gram-negative bacteria Scope, curriculum outline, expectations Basic microbiology and infectious diseases Microorganism> Commensals vs Pathogens > interactions with the host and pathogenesis of disease> common pathogens (bacterial & parasitic, fungal and viral) > Antimicrobial Agents for treatment and drug resistance > Investigating infections/fever > Infection Control to prevent infections > Prophylaxis and Vaccines Systems-based microbiology and infectious diseases Infections in systems (cardiovascular, respiratory, renal etc) Expectations/advise Time and attention: it is a new language – names of organisms, antimicrobial agents, etc. Understand the principles and be able to apply your knowledge Build a scheme of common pathogens and associated diseases Infectious Diseases in the modern world Globally in 2019, 85 different pathogens accounted for 28% of DALYs from all causes SSA – 62% High-income super region – 10% Top 3 diseases: TB, Malaria and HIV Malaria no 1 in under 5 years of age Substantial burden from gram-positive and negative organisms Lancet Infect Dis 2024; 24: 868–95, https://doi.org/10.1016/ S1473-3099(24)00158-0 Pathogen classification and genomic sizes Viruses: DNA and RNA (ss and ds), enveloped and non-enveloped Influenza (13.5kb), HIV (9-10kb) Procaryotes: bacteria, mycobacteria, actinomycetes E.coli (4.5-5.5Mb), M.tuberculosis (~4Mb), Eucaryotes: fungi, protozoa and helminths C.albicans (~14Mb), Plasmodium falciparum (~23Mb), O. volvulus (97Mb) For comparison – Homo Sapiens (3Bn) From Exposure to Disease Incubation periods Short (hours to days) Cholera (2hrs – 5d) Influenza (1-3d) Intermediate (days to weeks) Chickenpox (11-20d) Malaria (10-15d) Long Hepatitis B (6wk- 6mo) TB (1-12 mo) https://doi.org/10.3389/fmicb.2024.1370818 Davidson’s principles and practices of Medicine, 24th edition Modes of transmission http://dx.doi.org/10.1016/B978-0-12-803678-5.00516-6 Faeco-oral transmission http://dx.doi.org/10.1016/B978-0-12-803678-5.00516-6 Exogenous encounters Animal transmitted (zoonotic): Rabies, toxoplasmosis, brucellosis Insect vectors: mosquitoes (Malaria and dengue) and ticks (tick- bite fever) Human transmitted: Sexual transmission – HIV, chlamydia Airborne –Varicella (chickenpox), TB (