Bacteria Definition
Bakterion (Greek), small staff
Pathology
Pathos (Greek), suffering
Genesis
Genesis (Greek), origin
Upon infection
There are many steps before getting sick.
fungi and eukaryotes vs bacteria
which one is more closely related
Fungi and eukaryotes are closely related. Bacteria is no as closely, on the tree of life.
overview of bacterial infections
Bacterial Meningitis (brain)
Otitis Media (ear)
Pneumonia (lungs)
Eye infections
Sinusitis (sinus)
Upper respiratory tract (nose)
Gastrict
Food poisoning (intestinal)
Skin infections
Sexually transmitted diseases
Urinary tract infections
First Plague
541-543
First Yersinia plague
In total, there have been three Yersinia Plagues in the world.
Tuberculosis
current infectious disease (18 -19th century)
One of the oldest diseases known to humanity, it has been called many things before that
Burden and risk
Bubonic Plague : 15-100million deaths
Black death : 25-50 million deaths
Covid-19 pandemic : 7-35 million deaths
Tuberculosis, mostly in African and underdevelopped contries, 1.3M deaths per year
Lyme disease
Reservoirs of Lyme ticks are moving north due to global warming. More Deers are mving up norht and thus getting more ticks
Antimicrobial Resistance
Threatens our ability to treat bacterial infections.
Medium Group : easier to treat, like streptococcus
High Group : Salmonella Typhi, very hard to treat
Critical Group : Impossible to treat, tuberculosis
Bacterial Pathogenesis
Understand how bacteria cause disease can lead to the development of better methods to control bacterial diseases.
Also the study of how bacteria that live harmlessly within us occasionally harm us.
- What is Pathogenesis
- What is Symbiosis
- What is Virulence
- What is Pathogenecity
- What is a Virulence Factor
- What is colonisation
- What is an infection
- What is disease
- Capacity to cause Pathology
- Two divergent species live together
- Quantitative (severity)
- Qualitative (capacity)
- Bacterial product -> virulence
- Organisms live on our surface
- Organisms breach our barrier
- Disorder of structure of fucntion
Ulcers
Until the 1980s, people thought it was due to stress and spicy food.
Barry Marshall, believed it was a bacterial infection
Most people were sceptical
Many attempts to culture bacteria from ulcers were unsuccessful.
Over the Easter weekend, plates were left, small colonies were present. He drank the bacteria, and got sick, and following an endoscopy, he was found to have an ulcer.
Helicobacter pyroli and human disease
Gram negative bacterium
30-50% of the world’s population
Majority are asymptomatic stomach infections -> neutralizes the stomach acid by producing ureases
causes
- acute gastritis
- peptic ulcer disease
- gastric cancer
- N.B. Only bacteria to be classified as a carcinogen by the WHO
Define a pathogen
Koch’s postulates
1. the pathogen must be present in all cases of the disease and absent from healthy animals.
2. the suspected pathogen must be growb in pure culture
3. cells from a pure culture of the suspected pathogen must cause disease in a healthy animal.
4. The suspected pathogen must be reisolated and shown to be the same as the original
Not all host / bacteria interactions lead to diseases
Bacterial Factors:
- Route, Number, Virulence potential
Host Factors:
- Host health status, host defences/genetics
What are required steps
- Maintain a reservoir
- Be transported to the host
- Adhere to, colonize, and/or invade host
- Multoioply or complete life cycle on or in host
- Evade host defenses
- Leave host and return to reservoir or enter new host
