E1 Ch 6 Infection Flashcards
microbiology
the study of microorganisms, very small living forms that are visible only with a microscope
microorganisms
include bacteria, fungi, protozoa, viruses
can be:
nonpathogenic
-usually do not cause disease unless conditions change
-part of normal flora
- often beneficial
or
pathogenic
-disease-causing microbes
bacteria
- no nuclear membrane or nucleus
- function metabolically and reproduce
- cell wall
- do not require living tissues to survive
- can be gram+ or gram-
- flagellae or pili used for mobility or attachment
- may secrete toxins or enzymes that damage tissues or antibiotics
- some form spores, which are highly resistant to heat and disinfectants, and can remain dormant for long periods of time
- reproduces with binary fission
- treated with antibiotics
virus
- mutates quickly
- often use vaccines to protect against them
- DNA and RNA
- hijacks human cells to manufacture viral DNA/RNA, lysis of cell allows spread of virus
- can become latent then active later (ex shingles)
- can only live short period on surface
- treated with antivirals
protozoa
- may live independently
- lacks cell wall
-treated with antiprotozoals/antimalarials
ex: trichomoniasis (trichomonas vaginalis is an STI), malaria (plasmodium found in RBCs, spread by mosquitos)
fungi
- rarely pathogenic
- treated with antifungals
- generally topical, though can be symptomatic
- hyphae under microscope
ex: tinea (tinea pedis: athletes foot, tinea corporis: ringworm, tinea cruris: jock itch), candida (thrush and vaginitis, opportunistic infection), pneumocystis jirovecii (opportunistic organism causing pneumonia, commonly seen with AIDs), histoplasma (can cause neuro disease and can be transmitted to fetus)
helminths
- parasites
- treated with antiparasitics
- enter body through skin, ingestion, inhalation
- infections more common in young children
normal flora
normal flora live on your skin and protect you from pathogenic infections taking over; found in/on skin, mucous membranes, GI, etc.
resident flora present
skin, nose, pharynx, mouth, colon, rectum, vagina
sterile area
blood, cerebrospinal fluid, lungs, uterus, fallopian tubes, ovary, bladder, kidney
sporadic transmission
in a single individual
endemic transmission
continuous transmission within a population
epidemic
higher than normal transmission or spread to new geographical area
pandemic
transmission has occurred on most continents
chain of infection
how to prevent infection
PPE, hand washing, covering coughs, rabies vaccines for dogs, avoid sick people, protect immune system, cleaning surfaces, eliminate vectors, mask when sick, treat pathogens
1 way to prevent infection
hand hygiene
factors that decrease host resistance
age (infancy and older adults), pregnancy, genetic susceptibility, immunodeficiency, malnutrition, chronic disease, severe physical or emotional stress, inflammation or trauma, impaired inflammatory response
pathogenicity
capability of a microbe to cause disease
virulence
disease producing power, degree of pathogenicity
nosocomial
occurs in hospitals, spread by healthcare workers, increased risk with depressed immune system
prevent with proper hand hygiene, clear contaminated objects, clean surfaces
standard/universal precautions
PPE to avoid bodily fluid (gloves, goggles, etc.)
others used in addition (airborne, droplet, contact, etc.)
local signs of infection
pain, swelling, redness, warmth, purulent exudate (pus) if bacterial, serous clear exudate if viral
systemic signs of infection
fever may be present, fatigue and weakness, headache/nausea
methods of diagnosis
culture and staining techniques (used to identify causative agent, drug sensitivity tests)
blood tests
- variation in the number of leukocytes (leukocytosis: bacterial infection, leukopenia: viral infection)
- differential count
- c-reactive protein
- erythrocyte sedimentation rate
incubation period
body is exposed, asymptomatic
prodromal period
nonspecific symptoms
acute period
infectious disease develops fully
