BACTE LEC - Quiz 1 Flashcards
source of infecting agent
Reservoir
means by which humans may acquire microorganisms
Mode of Transmission
living entity that transmit microorganism from the reservoir to host
Vectors
nonliving entity that transmit microorganism from the reservoir to host
Vehicle or Fomite
Identify bacteria present in Chicken
– Salmonella spp.
Identify bacteria present in Rat’s urine
– Leptospira interrogans (cause of leptospirosis)
Identify bacteria present in Cat’s scratch –
Bartonella henselae
Identify bacteria present in Tick in rats –
Yersinia pestis
fever caused by ticks
*Rocky Mountain Spotted Fever –
Many fungal agents are acquired by ??? of soil and dust particles containing microorganisms and through ???
inhalation
penetration of wounds
Factors that Cause Diseases
- Status of host’s immune system
- Protection from microbial invasion
- Inherent microbial factors
Types of Microbial Flora
- commonly found on or in body sites
- beneficial: compete against pathogenic bacteria for nutrients and space so these pathogens won’t be able to use it to their advantage
- overpopulate so pathogens will not be able to live at a certain site of the body
- Normal, usually indigenous flora
Types of Microbial Flora
colonize an area for months/years
resident
hosts with pathogenic organism but not manifesting symptoms, capable of transmitting infections
carrier
Types of Microbial Flora
present at a site temporarily
transient
bacteria always present on skin/nose
Staphylococcus aureus
infection caused by microbes with low virulence but becomes pathogenic in a host with low immunologic response
Opportunistic infection
Composition of Microbial Flora at Different Body Sites
Skin
sebaceous/sweat glands, squamous cells (keep on shedding/dislodging bacteria)
Composition of Microbial Flora at Different Body Sites
mouth
low redox potential at tooth surfaces (anaerobes)
Composition of Microbial Flora at Different Body Sites
Respiratory tract
alveolar macrophages
delivery of air from the outside of body to pulmonary tissues
Composition of Microbial Flora at Different Body Sites
Sweat
contains lysozymes which destroy bacterial cell wall
found in sweat, destroys bacterial cell wall
lysozymes
found in respiratory tract, phagocytose
alveolar macrophages
Composition of Microbial Flora at Different Body Sites
GIT
gastric acidity
PATHOGENESIS OF INFECTIOUS DISEASES (2)
a. Suppression by immunosuppressive drugs, chemotherapy or radiation
b. Individuals with lymphoma, leukemia, chronic illnesses, cirrhosis
invasion of a pathogen with structural or functional harm, characterized by signs and symptoms
*Infectious diseases
bacteria in oyster
Vibrio cholera
invasion or growth of a pathogen
Infection
infection which develop quickly
Acute infection
infection which develop and progress slowly, sometimes in a period of years
Chronic infection
disease which spread from one person to another or from an animal to a person
-spread often happens via airborne viruses or bacteria, but also through blood or other bodily fluid
*Communicable/contagious/infectious -
disease which do not spread from one person to another or from an animal to a person
*Non-communicable
– cases are isolated in a given community, disease occurs only rarely and without regularity
Sporadic
steady cases of occurrence of disease in a given area
endemic
sudden increase of infection in a given area)
outbreak
continuous increase of infection
epidemic
occurs worldwide (Ex. Ebola)
pandemic
opposite of endemic
outbreak
– the spread of diseases; new cases of infection
Incidence of disease
– study of present and previous infection
-how seriously and how long it affects a population
Prevalence of the disease
– make the body more susceptible to disease or alters the course of a disease
Predisposing Factors
what are the predisposing factors (9)
- Gender
- Age
- Fatigue
- Environment
- Lifestyle
- Pre-existing illness
- Chemotherapy
- Emotional disturbances
- Habits
Patterns of Disease (normal cycle)
time when the person developed the disease but is not manifesting signs and symptoms, lag phase
incubation period
Patterns of Disease (normal cycle)
varies, time when the person Is exposed to an agent
prodromal
Patterns of Disease (normal cycle)
manifesting signs and symptoms
illlness
Patterns of Disease (normal cycle)
time when the person is starting to feel better; signs and symptoms subside
decline
Patterns of Disease (normal cycle)
development of antibody
convalescence
Pathogenic Determinants (Elements of the microorganism that prevent it from being killed and thus be able to infect another organism)
- Adhesins
- Capsule – prevents phagocytosis
- Cell Wall Components
type of toxin
toxic substances secreted by bacteria and released outside the cell
- Exotoxins
bacterial toxins consisting of lipids that are located within a cell
Endotoxins
type of toxin
produced by Gram-positive
exotoxins
type of toxin
protein in nature
exotoxins
type of toxin
effects: specific for a particular cell structure or functions in the host
exotoxins
type of toxin
produced by Gram-negative
Endotoxins
type of toxin
lipopolysaccharides (LPS) in nature
Endotoxins
type of toxin
effects: general such as fever, weaknesses, aches and shock all have the same effects
Endotoxins
– a toxin having a specific toxic action on cells of special organs
Cytotoxins
cause massive RBC destruction
hemolysin
related to food poisoning and cause diarrhea
enterotoxin
-inhibits protein synthesis
diphtheria toxin
causes skin layers to exfoliate and slough off
exfoliative toxin
prevents transmission of nerve impulses causing flaccid paralysis
(botulinum toxin)
-causes vasodilation resulting in characteristic rash (Scarlet fever)
CYTOTOXIN
-associated with toxic shock syndrome
(TSST-1)
– canned good bacilli, anaerobic
Clostridium botulinum
