1. Fundamentals of Medicine (Pathology) Introduction to Microbiology
Peter Gayo Munthali
Consultant Microbiologist
UHCW

2. Aim
To introduce to you general principles in microbiology with an emphasis on bacteria and viruses

3. Objectives By the end of the session you should be able to;
Describe the role of a clinical microbiologist/virologist in patient care
Describe the difference between bacteria and viruses.
Distinguish between gram-positive and gram-negative bacteria
Describe bacteria by their shape as either cocci or rods
Describe the relationship between viruses and cells in viral multiplication
Name some common bacterial and viral diseases linked to their causative organisms
Describe in broad terms, how antibiotics work on bacteria
Describe the importance of infection control in health care

4. What is Microbiology The study of micro-organisms that cause disease
Bacteria (Bacteriology)
Viruses (Virology)
Parasites (Parasitology)
Fungi (Mycology)

5. Size Matters Light microscope Electron Microscope 1nm 10nm 100nm 1 µm
Proteins
Viruses
Plant and animal cells
Bacteria
Small molecules

6. 1. Bacteria

7. Description Unicellular Prokaryotic Genome Structure Primitive nucleus
No nucleus membrane
Genome
Single circular molecule double stranded DNA
Can harbour independent small circular DNA molecules called plasmids
Structure
Rigid wall which determines their shape

8. Bacteria and Human body
Bacteria >10x than human cells in the body (10¹ versus 10¹³)
Skin surface and in deep layers
Saliva and oral mucosa
Gastrointestinal tracts
Normal microbiota or microflora
Beneficial to human health
Opportunistic infections
< 10% culturable
Others not part of normal microbiota
Pathogenic
Opportunistic pathogens

9. Bacteria Classification
Cell wall classification by gram-stain
Gram positive-thicker cell wall
Gram negative-thinner cell wall
Classification by shape
Spherical-Cocci
Cylindrical-Rods/bacilli

10. Bacteria Classification

11. Gram Stain Gram-Positives Gram-negatives Gram-negative rods
Gram-positive cocci in clusters (Staphylococci)
Gram-positive rods
Gram-positive Cocci in chains (Streptococci)
Gram-negative cocci

12. Sub classification-Streptococcus
Short Chain
Diplococci
Beta (β) haemolysis
Long Chain
Gamma (γ) No Haemolysis
Alpha (α) haemolysis

13. Cell Division (binary fission )

14. Bacterial Cell Division
Super coiled DNA
DNA relaxation and duplication
Duplication of the DNA
bacterial chromosome replicates leading to two identical chromosomes
Enzymatic Cleavage
Division
Identical Daughter cells

15. Bacterial Diseases

16. Impetigo
Staphylococcus aureus
β haemolytic Streptococci

17. Rash due to Septicaemia
Meningitis, Post-mortem
Neisseria meningitidis
Streptococcus pneumoniae
Gangrene Secondary to Septicaemia

18. Streptococci pneumoniae
Community Acquired Pneumonia
Streptococci pneumoniae
Consolidation
“Atypical Pneumonia”
Legionella
E.coli
Hospital Acquired Pneumonia

19. Beta Haemolytic Streptococci Group A
Necrotising Fascitis

20. Antibiotics Actions Bactericidal
Kills bacteria, reduces bacterial load
Bacteriostatic
Inhibit growth and reproduction of bacteria

21. Antibiotics Against Bacterial Cell Wall
Osmotic Pressure
Cell Membrane
Antibiotic against cell wall
Osmotic Pressure
Cell membrane
Rapture

22. Antibiotics Against Protein Synthesis
Interferes with bacterial protein synthesis
Limits bacterial growth
Limits DNA replication
Limits bacterial cellular metabolism
Bacterial growth and reproduction inhibited

23. Antibiotic Susceptibility Testing By Disc Diffusion method
Antibiotic Disc
Zone of Inhibition
Diameter of Zone of Inhibition
Sensitive/Resistant
Quick
Convenient

24. Viruses

25. Description
Small infectious agents that can replicate only inside the living cells of organisms
Do not possess enough of their own machinery to replicate independently
Bacteria replicate independently

26. Viral Classification More complex than bacteria Nucleic acid DNA RNA
Morphology
Enveloped
Naked

27. DNA viruses
And Associated Diseases

28. Family
Examples
Disease
Poxviruses
Variola
Smallpox
Herpesviruses
Herpes simplex
Varicella-zoster
Cytomegalovirus
Chickenpox
Adenoviruses
Sore throat,
conjunctivitis
Hepadnaviruses
Hepatitis B
Hepatitis
Papovaviruses
Papilloma
JC virus
Warts
Parvoviruses
B19
Erythema infectiosum

29. Viruses by Electron Microscopy

30. Varicella Zoster Virus
Chicken Pox
Shingles
Varicella Zoster Virus

31. Small Pox

32. And Associated Disease
RNA Viruses
And Associated Disease

33. Family Viruses e.g. Diseases Orthomyxoviruses Influenza
Paramyxoviruses
Parainfluenza
Respiratory syncytial
Measles, Mumps
Respiratory infection
Coronaviruses
Coronavirus
Resp.infection
Rabdoviruses
Rabies
Picornaviruses
Polio
Caliciviruses
Noroviruses
Gastroenteritis
Togaviruses
Rubivirus
Rubella
Flaviviruses
Hepatitis C
Hepatitis
Bunyaviruses
Hantavirus
Haemorrhagic fever
Retroviruses
HIV
HIV/AIDS
Filoviruses
Ebola virus
Marburg virus
Ebola haemorrhagic fever
Marburg haemorrhagic fever
Reoviruses
Rotavirus
Arenaviruses
Junin, Lassa viruses

34. Global status Polio 2003

35. Noro Virus

36. Human Immunodeficiency Virus (HIV)
Viral
Fungal
Opportunistic Infections
Opportunistic Infections
Opportunistic Infections
Parasites
Bacterial
Opportunistic Infections

37. Viral Replication

38. Viral Genome DNA or RNA Double-stranded Single-stranded RNA viruses
Intact or segmented

39. Viral Replication-Key Points
Need to be in a live cell to replicate
Uses cell machinery for replication
Some individual differences according to viral genome and particular virus

40. Fungi
Structure
Classification

41. Fungi Classification Yeast Moulds Unicellullar,reproduce by budding
Filamentous ,produce by spores

42. Yeast-Candida
Candida, Gram-stain
Streptococci

43. Candidiasis

44. Aspergillus fumigatus
Moulds-Aspergillus
Aspergillus flavus
Top
Bottom
Aspergillus fumigatus

45. Aspergillus , Microscopic appearance
Scanning Electron Microscopy

46. Mould sinus infection
Mould Infections
Aspergilloma

47. The Role of Microbiologist in healthcare
Management of diagnostic laboratories
Management of infections
Antibiotics advice, choice and duration
Choice of appropriate investigations
Infection prevention and control in hospital and the community
Investigation, management and control of outbreaks of infections
MRSA, Clostridium difficile, Noro virus
Commissioning of theatres, decontamination of facilities and wards

48. Never Forget Infection Control!
Noro Virus

49. Summary Microbiology is a very interesting discipline
Spans across all medical specialties