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47 Cards in this Set
- Front
- Back
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infection |
condition in which pathogenic microbes infiltrate host defenses, enters tissues, and multiply |
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Pathogen |
infectious agent |
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infectious disease |
condition that causes damage or disruption to tissues and/or organs |
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residents |
microbes that become established; less influenced by hygiene |
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transients |
microbes present for only a short period; more influenced by hygiene |
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microbial antagonism |
normal flora benefit host by preventing overgrowth of harmful strains |
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endogenous infection |
occurs when normal flora enter a site that was previously sterile |
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breaking of fetal membrane |
introduce what will be normal flora through feeding and handling |
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variations in GI flora |
due to shifting conditions in: oxygen tension, pH, anatomy |
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flora of the mouth |
most unique and diverse flora of the body -numerous adaptive niches -bacterial count of saliva: 5x10^9 |
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flora of the large intestine |
large and profound effect on host - intestinal environment prefers anaerobic bacteria |
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flora of the respiratory tract |
oral streptococci: first bacteria to colonize |
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factors altering flora |
antibiotics, diet, disease |
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major factors in development of infection |
1) portal of entry 2) attaching firmly via fimbriae, hooks, etc. 3) avoiding host defenses (phagocytosis, immune system etc. 4) damage and disease (direct: toxins/lysis; indirect: immune response is excessive) 5) exit via anus, skin, respiratory tract, etc) |
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true pathogens |
capable of causing infection in healthy people with normal immune response -influenza, plague bacillus, malarial protozoan |
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opportunistic pathogens |
cause disease when immune defenses are compromised or they grow in non indigenous areas - pseudomonas sp, Candida albicans |
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virulence factor |
characteristic or structure that contributes to the ability of a microbe to cause disease |
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Pathogens that infect during pregnancy |
Syphilis Toxoplasmosis Other diseases (hepatitis, AIDs etc) Rubella Cytomegalovirus Herpes simplex virus |
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phagocytosis |
initial response of immune system against infection |
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leukocidins |
produces by Staph and Strep species - toxic to white blood cells, inhibit phagocytosis |
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exoenzymes |
dissolve extracellular barriers and penetrate through or between cells |
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toxigenicity |
capacity to produce toxin at the site of multiplication |
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endotoxin |
type of toxin that is not secreted, but is pleased after the cell is damaged -composed of LPS, part of gram negative membrane |
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exotoxin |
type of toxin that is secreted from bacterial cell into tissue -hemolysins, A-B toxins |
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incubation period |
time from initial contact with the infectious agent to first appearance of symptoms; hours to years |
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prodromal stage |
vague feeling of discomfort; nonspecific complaints |
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period of invasion |
multiplies at high levels, becomes established - more specific symptoms |
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convalescent period |
as person begins to respond to the infection, symptoms decline |
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systemic/local/focal infections |
systemic - infections spreads to several sites and tissue fluids, usually in the blood stream local - confined to one site focal - infection breaks free from local site and spreads to other tissues |
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patterns of infection |
primary - initial infection mixed - several microbes grow simultaneously at the site of the infection secondary - another infection by a different microbe |
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signs of inflammation |
edema - accumulation of fluid granulomas and abscesses - walled off collections of inflammatory cells lymphadenitis - swollen lymph nodes |
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leukocytosis |
sign of infection in bloodstream - increase in white blood cells |
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leukopenia |
sign of infection in bloodstream - decrease in white blood cells |
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septicemia |
sign of infection in bloodstream - large numbers of bacteria are present and multiplying - bacteremia: small number present in blood - viremia: small number of viruses present |
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chronic carrier |
person with latent infection who sheds the infectious agent |
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sequelae |
long term or permanent damage to tissues or organs |
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reservoir |
primary environment of pathogen in natural world - humans, animals, soil, water, plants |
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source |
individual or object from which an infection is actually acquired |
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passive carrier |
contaminated healthcare worker picks up pathogens and transfers them to other patients |
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communicable disease |
when an infected host can transmit an infectious agent to another host and cause infection - highly communicable = contagious |
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non-communicable |
infectious disease that does transmit from living host to living host - occurs primarily when normal flora overgrow - also via contact with organism in non living reservoir |
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patterns of transmission |
direct: aerosol droplets or physical contact indirect: vehicles, inanimate material, food etc. |
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epidemiology |
the study of the frequency and spread of distribution of disease and health related factors in the human population |
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prevalence |
total number of existing cases with respect to the entire population, usually represented as a percentage of the popultion |
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incidence |
frequency of cases over a certain time period compared to general healthy population |
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morbidly rate |
number of people afflicted with a certain disease |
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koch's postulates (determining causative agent) |
1) identify particular microbe in every case of a disease 2) isolate microbe from subject in a laboratory 3) inoculate healthy patient with isolated subject and observe resultant disease 4) re-isolate subject from patient |
