Microbiology Topics 4, 5, + 6

micro lecture

commensalism

one benefits, one unaffected 

mutualism

both benefit

parasitism

one benefits and one suffers

opportunism

typically harmless until opportunity arises then becomes parasitic

Disease vs. Health is a balancing act between?

pathogen virulence and host immunocompetence

direct transmission

diseased and those they infect in the same place at the same time

sexual contact, bites, kissing, touching, fecal contact, and respiratory droplets are all examples of which type of transmission?

direct transmission

indirect transmission

diseased not in the same place and time with those they infect

vectors 

ex. mosquitos 

non-sick living organisms capable of transmitting pathogen to next individual

vehicles

contaminated air food or water

fomites

ex. furniture 

inanimate objects likely to carry infections

zoonoses

disease of animals

transmissible to humans 

animals themselves are not vectors

can be direct or indirect transmission from sick animal

reservoirs

the holding place for a pathogen in between infections, pathogen remains viable, potential threat to entire population 

vectors, vehicles, and fomites can be considered…? if a pathogen survives in/on them and infects lots of individuals over time

Reservoirs 

asymptomatic infected individuals who infect many over time are known as?

carriers

how may a Carrier pass a disease to another individual

via direct or indirect transmission

incubation stage

no symptoms + adjustment replication

prodromal stage

first vague symptoms present (slight fever, fatigue, malaise, anorexia)

acute “illness” stage

severe recognizable symptoms (vomiting, rash)

decline stage

recognizable symptoms STILL present, but become less severe and frequent

convalescence stage 

recognizable severe symptoms gone, but damage is still present and stamina is diminished

rapid onset, severe symptoms, rapid recovery

acute disease

peak severity of illness + turning point toward recovery or deterioration 

crisis point in an acute disease

delayed onset, less severe symptoms, NO crisis point (gradual transition between acute and decline)

prolonged recovery 

chronic disease

primary diseases

occur in preciously healthy individuals (pathogens of high virulence)

secondary diseases “piggy-back” 

follows another disease due to an immunocompromised host, this disease can be opportunistic or low virulence

secondary+sequelae

when the same pathogen gains strength and spreads to another location of the body 

nosocomial infections 

any infections acquired in a healthcare setting 

local infections

pathogen remains at portal of entry -portal may be an internal surface like the lungs. 

systemic infections 

spread through entire system or body 

a blood infection is called?

septicemia

the presence of viruses in the blood is called?

viremia

the presence of fungi (yeast or mold) in the blood is called?

Fungemia

the presence of bacteria in the blood is called?

bacteremia

focal infections 

when a wide spread organism relocalizes on an internal organ

endemic

stable and predictable levels

epidemic 

sudden outbreak, and an increase in numbers compared to baseline

pandemic 

an epidemic occurring on more than one continent simultaneously

Methicillin resistant staph aureus (MRSA)

Highly virulent

MANY portals of entry + causes MANY diseases

common nosocomial infection 

Vancomycin resistant enterococcus (VRE)

less virulent

less portals of entry+ causes fewer diseases+ resistant to MORE drugs

common nosocomial disease

Clostridium dificile (C.dif.)

mainly causes gut infections when normal glut flora gone + drug resistant.

common nosocomial infection  

the worst pathogens in a community would be found where?

in a hospital/healthcare setting

every patient in a healthcare setting is said to be?

immunocompromised

immunocompetence factors that a person can not control

age

genetics

ethnicity

immunocompetence factors that a person CAN control

nutrition

sleep

exercise

how do pathogens enter the body?

they must come in at the right portal of entry and the correct dose must be present

level one defenses

outer perimeter defenses that are always innate

level two defenses 

within the body defenses that are always innate 

level three defenses

adaptive immune response only when a pathogen is present.

adhesion is form of physical weapon that a pathogen has, what does this weapon do 

adhesion allows pathogen to stick tightly to host cells making it harder to get rid of. 

hairlike structures on bacteria helping them to tightly stick onto host cells (main adhesion component) 

Fimbriae

capsules are a physical weapon that help with the adhesion to surfaces, how

by providing a sticky outer layer that allows cells to attach to host cells, making it harder to get rid of.

bacterial enzymes

alter the substrate in host tissue

ligand adhesion and Fimbrae

allows adhesion to stick to surfaces and prevents flushing out of body

capsules

allows adhesion to surfaces, neutralizes drugs, delays immune response, and avoids phagocytosis 

invasins

makes pore in cell membrane, allows spread with axial filament, cause septicemia and focal infections

coagulase

forms blood clots (barrier), prevents entrence of WBC and drugs, causes local infections 

kinase

dissolves blood clots, allows pathogen to spread into blood stream, causes septicemia

Hyaluronidase

dissolves cell cement between cells, works together with Collagenase to spread through tissue (systemic)

Collagenase

dissolves fibers under cells, works together with Hyaluronidase to spread through tissue (systemic)

leucocidin 

death of white blood cells, prevents phagocytosis by WBC, causes pus formation

M proteins

pseudopods cant grab bacteria- repelled by M proteins, prevents phagocytosis by WBC

Hemolysin

ruptures red blood cells, reduces O2, increases CO2 for Microaerophiles leading to better incubation for bacterial growth

releases iron for nutrients

neurotoxin

blocks nerve from releasing neurotransmitter, causes flaccid paralysis in botulism and rigid paralysis in tetanus

Enterotoxin

Increased fluid loss and peristalsis, bacterial dispersal, causes Diarrhea, cramping, nausea

Cytotoxin

directly kills cells, bacteria invade cell and eat everything inside it, causes lesions

endotoxin

lipid, causes Fever, inflammation, BP drop, blood coagulation, etc.

digestive enzymes 

break down proteins, lipases, and amylase, protect bacteria from antibodies, WBC, and drugs, liquefies tissue 

tetanus

prevents inhibitory neuron neurotransmitter release

where are antitoxins made

in the body

where are toxoids made

in the lab

both antitoxins and toxoids are able to 

prevent disease symptoms from occuring 

DO NOT trigger immune response

DO NOT make antitoxins

DO NOT produce toxoids

endotoxins

Molecule type: lipid

Found in cell within LPS Layer

Gram reaction of producers: gram neg. cells only

released from cell: when it dies

endotoxins

communication between bacteria of the same species with collaborative behavior

intra specific communication 

communication between bacteria of different species with competitive behavior 

inter specific communication 

general term by which bacteria communicate

quorum sensing

viral cytopathic effects 

abnormalities of infected cells visible through a microscope in biopsies 

evidence viral infections are present

lesions and lack of function in organs

syncytium formation

cells next to each other merge into huge cell

multi nucleated cells

cells w/ more than one nucleus

inclusion bodies

clumps of host cell organelles or viral products seen inside cells

nucleomegaly 

bigger nuclei in cells 

enlargement 

cells distinctly larger

rounding

cells go from flat to spherical allowing pathogens to come inside