Microbiology Ch. 13 - Microbe - Human Interactions

normal resident microbiota

microbes that engage in mutual or commensal associations with humans

Many interactions between human body and microorganisms involve the development of _____________

biofilms

what is the significance of microbe-human interaction?

1. provide protective and stabilization effect on body
2. involved in development of immune system
3. can invade sterile tissues and cause infection

pathogen

an agent capable of invading sterile tissue and multiplying

infectious disease

disease that causes damage to tissues/organs

transients

microbes that only occupy the body for a short time

what keeps the pH of the vagina acidic?

fermentation of glycogen by lactobacilli

e.coli produces a protein that prevents the growth of ________________.

salmonella and shigella

what parts of the body have resident microbes?

skin, upper respiratory tract, GI tract, uretha opening, genitalia, vagina, external ear, external eye

what parts of the body are sterile?

internal organs and the fluids they produce

microbial antagonism

competition between normal microbes and foreign ones

people with compromised immune system can easily be infected by _____________.

resident microbes

what is an example of normal microbes negatively effecting an immunocompromised person?

AIDS patients developing recurring streptococcus pneumonia

what are the stages of how a microbe causes infection?

contact, colonization, invasion, infection

local infection

infection is limited to one part of the body

systemic infection

infection reaches blood and spreads to multiple parts of body

pyogenic

forms puss

pyrogenic

causes fever

most bacteria can grow well at ______.

37 degrees celsius

the normal flora only reside on _____________.

the dead cell layers

the fungi normal flora on the skin depend on __________ to grow.

skin lipids

the microbes in the lower GI tract are mostly __________.

anaerobic

the eye has __________________ staphylococci.

coagulase negative

what parts of the skin host resident microbes?

epidermis, sweat pores, sebaceous oil gland,

transient microbes can be influenced by a person's ___________.

hygiene

what bacteria causes acne?

propionibacterium

corynebacterium

gram positive bacili bacteria

what parts of the digestive system host resident microbes?

oral cavity, large intestine, rectum

the appendix harbors white blood cells and also ___________ normal microbes.

replenishes

what are the clinical stages of an infection?

incubation period, prodromal stage, period of invasion, convalescent period

true pathogens

cause disease in a healthy person; also known as a strict pathogen

incubation period

the period of time between exposure to the pathogen and the first signs and symptoms

prodromal stage

vague discomfort

period of invasion

pathogen multiplies at high levels and exhibits most toxicity. person experiences signs/symptoms of full blown infection

convalescent period

person regains strength and gradually recovers from infection

coliforms

gram-negative, non-spore forming bacilli that ferment lactose with acid and gas production

Staphylococcus aureus

commonly infects wounds and causes serious problems such as toxic shock syndrome or produces food poisoning

staph is a falcutative _________.

anaerobe

what can alter the normal flora?

antibiotics, dietary changes, and disease

what do probiotics do?

introduce known microbes back into the body

what are the developmental stages of an infection?

contact, colonization, invasion, infection

contact

pathogens find a portal of entry and adhere to the area

colonization

pathogen is in the body and begins to colonize

invasion

pathogen crosses host defense lines and enters tissues and organs of the body

infection

pathogen multiplies in tissues and triggers an immune response

what can pathogens use to attach to the host?

fimbriae, capsule, viral spikes, surface proteins

what is an opportunistic pathogen?

pathogen causes disease when the host is compromised; pseudomonas sp. and candida albicans

exogenous infection

originates outside the body

endogenous infection

infection arises from organism that were already in the microflora

estrogen stimulates the production of _____________ which contributes to the ___________ of the vagina.

glycogen, acidity

lactobacilli ferment ____________ to lower the vaginas pH.

glycogen

what are examples of a true pathogen?

influenza, malaria, common cold, rabies

virulence

degree of pathogenicity

how is virulence determined?

by ability to establish itself in a host and cause damage

what are examples of infections that must enter a specific portal of entry?

influenza and athlete's foot

what microbes can invade the eye?

chlamydia trachomatis, neisseria gonorrhoeae

STORCH

Syphilis, Toxoplasmosis, Other diseases (hepatitis B, AIDS and chlamydia), Rubella, Cytomegalovirus and Herpes simplex virus

what is the infectious dose?

the minimum number of microbes required to cause infection

microbes with smaller infectious dose have _____________.

higher virulence

exotoxins

small proteins secreted by bacterial cell into specific tissue; tetanus, diphtheria, cholera, anthrax,

endotoxins

systemic, causes fever, released after cell is lysed; meningitis

what does the salmonella exotoxin do?

the proteins alter actin formation which allows the bacteria to be engulfed into tissues

toxinoses

the effects of toxins and diseases caused by them

toxoid

inactivated toxin used in a vaccine

antitoxin

antibodies against a specific toxin

focal infection

systemic infection that began as a local infection

what is an example of a systemic infection?

influenza

what is an example of a local infection?

abscess or boil

what is leukocytosis?

an increase in leukocytes

what is leukopenia?

a decrease in leukocytes

leukocytosis is a sign of ___________.

infection

septicemia

growth of microbes in the blood

bacteremia

small presence of bacteria in blood

viremia

small presence of viruses in blood

what viruses enter through the GI tract?

hepatitis A

what are some pathogens that enter through the respiratory tract?

streptococcus (sore throat), meningitis, diphtheria, whooping cough, influenza, measles, common cold, mumps, chickenpox, rubella

what are the 3 categories of virulence factors?

antiphagocytic effects, exoenzymes, toxins

leukocidins

toxic to white blood cells

what bacteria release leukocidins?

staph and strep

what is a bacterium that can survive inside a phagocyte?

mycobacterium

what are examples of exoenzymes?

mucinase, keratinase, hyaluronidase, collagenase

hemolysins

exotoxin that disrupts cell membrane of red blood cells

what bacteria secrete hemolysins?

strep pyrogens and staph aureus

what is the difference between toxemias and intoxications?

toxemias are toxins that spread by the blood. intoxications are ingested.

exotoxins target ______________ while endotoxins have _____________ effects.

specific organs, physiological

signs of inflammation

edema, granulomas, lymphadenitis

sequlae

long-term/permanent damage to tissues or organs

some infections have the same ___________.

reservoir and source

biological vector

actively participates in a pathogen's life cycle

what is an example of a biological vector?

mosquito

mechanical vector

transport infection without being infected

communicable disease

disease that is spread from one host to another

noncommunicable disease

disease that is not spread from one host to another

diseases that are highly communicable are termed ____________.

contagious