Chain Of Infection: 1 Flashcards
List the 6 steps in the chain of infection
- Infectious Agent
- Reservoir
- Portal of Exit
- Transmission
- Portal of Entry
- Susceptible Hosts
What is an Infectious Agent
Something causing an infection
eg Bacteria, virus, fungi, protozoa, parasite
Define Standard Precautions
Safe practice offering protection to both HCW and patients from healthcare-related infections
Some examples of Standard Precautions
Hand Hygiene
PPE
Safe handling and disposal of sharps
Routine environment cleaning
Difference between prokaryotic and eukaryotic cells
Eukaryote cells are more complex
Prokaryotes do not have an enclosed membrane and they have no membrane-bound organelles
Residential Microflora
Species that are always in or on the human body
Beneficial Bacteria
Assist with various body processes
Opportunist Bacteria
Microflora that can potentially be harmful and can cause disease, such as E. coli
Describe some main features of bacterial structure and fucntion
- Glycocalyx / Capsule
- Cell wall
- Cell membrane
- Cytoplasm
- Ribosomes
- Nucleoid
- Plasmid
- Pili
- Flagellum
- Endospore
Glycocalyx function
Protects pathogenic bacteria from phagocytosis
Cell Wall Function
Maintains shape of cell, offers protection from environmental factors
Cell Membrane Function
Selectively permeable membrane that controls what enters and exits the cell
Cytoplasm Function
Substance of the cell inside the cell membrane, medium for many metabolic reactions of the cell
Ribosome Function
Protein synthesis found in random groupings no RER to attach to
Nucleoid Function
One continuous strand of DNA, contains all the genetic information for cell metabolism and reproduction
Plasmid Function
May be an advantage to the cell as some carry genes for antibiotic resistance
Pili Function
Helps to attach to surfaces
Flagella Function
Helps bacteria to move towards a favorable environment
Endospore Function
Resistant to heating and drying, formed by certain bacteria when conditions are unfavorable
List the main characteristics of Fungi
yeasts
Eukaryote cell that is unicellular, reproduced by budding and some may spore
List main characteristics of Fungi
molds
Eukaryote cell that is multicellular, describes as filamentous because they are made up of fine threads called hyphae, reproduce through spores either sexually or asexually
Characteristics of Fungi
Eukaryote cell consists of yeasts and molds. They are decomposers and are classified by how they reproduce.
Fungal Infection:
Superficial
Occurs on the outer part of the body
eg Tinea Pedis / Athletes Foot
Systemic
Affects tissues and organs deep within the body
eg Lungs - Aspergillious spp.
Opportunist
Caused by fungi that are normally harmless
eg Candida Albicans / Vaginal or Oral Thrush
Characteristics of a Protozoa
Eukaryote cells that are classified by movement
Movement of Protozoa consists of
Flagella
Cilia
Pseudopodia
No motile stage
Flagella
Whip-like tail that propels the cell through watery environments
Cilia
large number of hair-like appendages that move in synchronised waves to propel the cell along
Pseudopodia
Means false-foot. large cells surrounded by a membrane and lacks shape it moves by extending the cell membrane then allowing the cytoplasm to flow into the extension
No motile stage
Needs a host to carry it
protozoan diseases
Plasmodium spp causes Malaria
Giardia intestinalis causes Giardiasis
Toxoplasma gondii causes Toxoplasmosis
Structure of a virus
Single type of nucleic acid
Protein coat / capsid
Envelope
Spikes
Characteristics of virus
Viruses do not have a cell structure
Require a host cell to reproduce
Obligate intracellular parasites
Steps in Viral Replication
Attachment to host cell
Entry and uncoating
Replication of viral nucleic acid and synthesis of viral proteins
Assembly of new complete virus
Release of virus particles from host cell
Viral Infections
Influenza Measles Mumps Rubella Herpes virus Polio
