microbiology ch9. infection and disease: unit 4

yes, but new evidence suggests that acquisition of the maternal microbiome starts in the womb

are babies free of microbes in utero?

microbes will start to colonize the infant's intestines
lactobacilis is foundi nthe birth canal
starting to form a symbiotic relationship

during bith, the baby is exposed to microbes and what will this start?

from birth and even before

when do humans and microbes start ot establish a symbiotic relationship?

symbiosis

describes the close relationship between 2 different types of organisms in a community
mutualism and parasitism

nutualism

both members benefit from the interaction
ex: ecoli in the human gi tract

parasitism

one organism benefits while the other is harms- slightly or killing the host

pathogen

parasite causing a disease

flora

normal microbiome

birth canal

where is the newborn's 1st contact with microbes?

breathing, feeding, throughout life(in mucus membranes open to the environment)

what is followed after the newborn's first contact with microbes after the birth canal?

to protect the baby

why is the immune system comproomised in pregnant people?

resiedent microbiome

microbiome that is always present and remains part of the normal mcrobiome throughout life
usually get them in early life and they stay with you forever= good friends

transient microbiome

found in the same locations as a resident microbiome but they only remain for for a few hours, months, or days before they vanish

stapphylococcus a.

what is an example of a microbe of the transient microbiome?

antimicrobials

bad to use them in everyday life because they kill the weak microbes and allow the strong ones to stay and replicate- killing the good microbiome and allowing the bad microbes to take over, these surviving microbes are also often antibacterial resistant microbes

around 70%

how much of HIA's are cause by antibiotic resistant microbes?

pathogen

a microorganism that is capable of causing disease

microbes of the normal flora can become opportunistic pathogens and the frenemies take over

when balance is not maintained between normal microbiome and human host and it is interrupted what happens?

fremeies microbiome

these microbes usually do not cause disease in normal habitat in a healthy person, however, when conditions change, they grow too much or in the wrong place

e coli causing a uti, they are normally found in the intestines but when they are not in the right place, they cause a problem/infection.
they are good in the right place but bad in the wrong place

what is an example of an opportunistic pathogen?

yes, competition for bad microbes for thier existance

is the normal microbiome protective?

when it goes into areas of the body where they are nor present under normal circumstances

when is our normal microbiome a problem?

portal of entry

sites where pathogens enter the body
any orface

exogenous

source of infection from the outside of the body

endogenous

source of infection that the organisms is already in the body (normal microbiome)

the same area that support normal microbiome
anything open tot he outside world

what are portal of entrys usually?

yes, htye have to enter through the particular opening to cuase a disease
l-r pathogens have to bind to different cells
if they enter the wrong one, no infeciton will occur

do microbes have a preferred portal of entry?

yes, strep and staph do this, they can affecy many parts of. the body

do some infectious agents enter via more than one portal of entry?

skin

biggest barrier and immune organ
top layer keratinized
thick

hair follicles, pores, sweat glands

what are some natural opening in the skin that pathogens can enter through?

gastrointestinal tract

one of the most common portal of entry for pathogens
poe: food, liquid, and other ingested substances
enteric bacteria

salmonella, shigella, vibrio, and certain strains of e coli

what are some enteric bacteria in the gastrointestinal tract?

polio, hep a, echovirus, and rotavirus

what are some viruses in the gastrointestinal tract?

entamoeda, histolytica, and giardia lambia

what are some protozoans in the gastrointestinal tract?

virulence factors

gives bacteria molecules that make them become pathogenic
getting plasmids

plasmids, antibiotic resisitance, and virulence molecules

what are osme things that plasmids can have?

virulence molecules

molcules that allows the pathogen to be more pathogenic

orla fecal route and can cause inflammation of the liver

How is Hep A transmitted?

malaria, giardia

what is the most famous protozoans?

respiratory tract

most frequent portal of entry for pathogens
has cilia to help sweep out the pathogens stuck in the mucus

sore throat, meningitis, diphtheria, whooping cough

what do the bacteria in respiratory tract usually cause?

agent cuasing the common cold, flu, measels, mumps, chicken pox

what do the viruses in respiratory tract usually cause?

urogenital tract

pathogens usually contracted by sexual contact

uti by ecoli, vaginal infections by candida albicans

what are some opportunistic infections by the urogenital tract?

conjuctiva

usually a good barrier against infectious agents
sine bacteria can easily attach to this membrane
pinkeye, chlamidia, gonorrhea

yes, for example, hepatitis a b and c they all cause inflammation of the liver but they are different viruses and are transmitted. differently

can the same disease be cause by different pathogens?

virulence

the degree of pathogenicity
disease provoking power of a specific microbe

1.virulence factors of microbes
2.number of microorganisms
3.portal of entry
4.host defense

what factors is related to pathogenicity?

yes, different places of the boy have different cells and levels of microbiome.

does the place that you get an infection determine its affectiveness?

adhesion

what is the first step of infection?

without adhesion the organism will be removed by different barrier mechanisms
sneezing, coughing, urination, tearing up in eyes, bowel movements

why does adhesion need to occur for infection?

pili, fibria, or specific membrane receptors sites , capsids
can be specific or non specific

in what ways can bacteria adhere to the host cells?

tissues that re in contact with the external environment. urogenital, digestive, respitory, conjunctiva

human pathogens usually colonize in what tissues?

1.avoid contact with phagocytes
2.inhibiton of phagocytic engulfment
3. survival inside the phagocyte
4.generation of products that kill or damage phagocytes before or after ingestion
5. enzymatic activity that damages the immune molecules

what are some ways that microbes can evade host cells?

this is the number one technique against the host
why pick a fight when you dont need to

describe how microbes can evade host cells by avoiding contact with phagocytes

some microbes are more resistant to being eaten due to capsid, slippery and avoid being recognized by the immune system

describe how microbes can evade host cells by inhibitions of phagocytic engulfment

some microbes can live in a phagocyte and stop digestion of the microbe
tuberculosis does this
surviving and replicating within the cell and not being detected by the immune system

describe how microbes can evade host cells by surviving within the phagocyte

conjunctiva

mucousa membrane surrounding the eyes
usually a good barrier against infectious agents
some bacteria can easily attach to this membrane
pinkeye,chamydia(newborns and abortion), gonorrhea

the pathogens activiely fight agaisnt the immune system with toxins and these kill the cells

describe how microbes can evade host cells by generation of products that kill or damage the phagocytes before or after ingestions

enzymes used to kill/damage immune molecuels-wbc
similar to the hemolytic activity: destorying the rbc

describe how microbes can evade host cells by enzymatic activity that deactivated the immune molecules

exotoxins

toxins from outside the cell
proteins that are released by bacteria during exponential growth phase
can act at sites other than the location of infection
toxins produced are often species specific and assiciated with a particular disease

leukocidim

staph a. is one
disrupts neutrophil membrane and granule discharge kills the PMN

streptolysin

strepto pyrogens is one
repels phagocytes, induces lysosomal discharge

hemolysin

strep spp is one
phospholipase that lyses several types of cells including rbc's.

tetanus toxin

prevents the breakdown of neurotransmitters resulting in permanent muscle contraction

e coli toxins

(heat liable and stable) increases water and electrolyte secretion from intestines causing fever, severe abdominal cramps and bloody diarrhea.

endotoxins

part of the bacteria itself, structure, and molecules

lippopolysaccharides

endotoxin
gram negative cell wall
cell shads lps, leaving a trail where the bacteria is=problem

released during lysis initiated by host defense or by action of antibiotics

when is lps released?

1.fight with immune system: lps sheds with every punch leaving more lps
2. antibiotic: kills bacteria and lps is released

what are the 2 ways to combat gram negative lps?

the bacteria can be dead but the lps is still able to roam around as a toxin since it is shed from the bacteria
-causing fever, and can cause most cases of septic shock

how can lps roam around after the bacteria is dead? what does this cuase?

it is a pyrogen=fever
inflammatory reponse and can cause septic shock=multi organ failure
around 705 septic shock is caused by lps

what can lps cause?

endotoxins are less potent and less specific than endotoxins

what is the relationship between exotoxins and endotoxins?

portal of exit

site of pathgoen leaving the infected person
often the same as the portal or entry

coughing, sneezing, diarrhea, oral fecal route
natural excreted/secretion mechanisms of the body: any body fluids

what are some portals of exit?

1.the study of the cause of the disease
2. patterns of infection

what are some aspects of he etiology of infectious dieseases?

disease

when the infection causes pathological changes to the host

infection

the microbe present within the body and may or may not cause disease
can be a carrier or have symptoms

infection have varied pattersn and are normal accordingly
people can get infected with multiple things at the same time
can have a cols and get an std at the same time
busy fighting something and more at risk for another infection

what are some aspects of patterns of infection?

local infection

orgnaism remains confined to a specific tissue

systemic infection

infection spreads to several sites and tissues, fluids, usually through the circulatory system

acute infection

appears rapidly with severe systems and vanishes rapidly

chronic infection

usually less severe symtpoms that acute, but they persist for long periods of time

mixed infections

several infections agents concurrently establish themselves at the same time

primary and seconday infections

what are some patterns of infection?

primary infections

you can an infections
initial infection

secondary infection

has to follow a primary infection
ex: pneumonia can be caused b y many different pathogens
HIAs many times become this

subclinal infections

does not cause any apparent symptoms
can be carried over long periods of time
ex hiv and aids

koch's postulates

gold standard of infectious diseases
important in figuring out a particular microbe is causing a specific disease

suspected pathogen must be present in all animals presenting with the disease and absent in healthy animals

explain the first step in koch's postulates

microbe must be isolated from the diseased and grown in a pure culture outside of the host

explain the second step in koch's postulates

pathogen from the pure culture must cause the same disease when inoculated into a healthy, susceptible host

explain the third step in koch's postulates

same pathogen must be isolated from the experimental host and must be shown to be identical to the original pathogen

explain the fourth step in koch's postulates

dont know how/ what to grow the bacteria in and viruses
-bacteria are picky eaters
-we know the person is infected and has the disease but cant grow the pathogen in lab

how is some pathogens. cannot be cultured in the lab and exception to koch's postulates?

ex: hapetitis: inflammation of the liver, but caused by different pathogens, hep a, b,c,d. all are transmitted differently
-pneumonia can be caused by many different pathogens as well but all cause disease of lungs

how is many infectious diseases can be caused by various pathogens an exception of koch's postulates?

organism may use different portals of entry-affecting outcome
ex: staph aurues: part of microbiome but can cause many different types of infections, skin, pneumonia, endocarditis

how is a particular pathogen can cause more than one infection an exception to koch's postulates?

kid scratches his knee and many different types of microbes can and will enter and getting an infection with more than one type of microbe, thus one microbe is not the cause of the infection / disease, thus cant use koch's postulates
Pneumonia is caused by many different pathogens

how is some diseases are caused by a combination of pathogens an exception to koch's postulates?

many people have e coli but when displaced it creates a problem, thus even though you isolate it, it is a part of the normal microbiome and does not cause a problem in the right place
may be there all the time and only cause disease under certain circumstances

how are opportunistic pathogens an exception ot the kich postulates?

cant infect animals in the lab,(sti) cant use koch's postulates. only can use humans to study pathogens

how are some pathogens only infection humans a exception ot the kich's postulates?

epidemiology

study of the distribution and cause of disease in populations
solutions are dependent on knowing what it is, and dealing with and how it works
-foundation and logic of interventions needed in the interest of public health and preventative measures