Infection Flashcards
Bacteria
Unicellular, prokaryotes, no nuclear-categorized by shape (spherical is cocci, rods is bacilli, spirals)
Pilus, flagella, cell wall phospholipid and protein are important for drug interventions, capsule-keeps from getting engulfed by phagocytes, nucleoid enzymes promote infection and damage, biofilms-matrix secreted by bacteria to protect them
Clinical stages of infection
Incubation period: 1st exposure to infectious period hours to years, no symptoms, low pathogen load but growing
Prodrome period- vague mild symptoms, pathogen continues to grow
Period of illness-severity worsens, both immune and inflammatory response triggered, growth toward peak
Period of decline- decrease if tx or immune wins, peak decline
Period of convalesce-decrease until resolved
Stages of infection
Invasion/penetration (transmission)-infectious agent/antigen invades the body, avoids immune detection, triggers inflammatory response
Multiplication- time of rapid cellular growth and division, occurs before the immune system can respond
Spread/tissue damage- local or disseminated presence of disease causing agents
Colonization- presence of infectious agents on a body surface without causing disease to the person
Outbreak
Greater than anticipated increase in number of endemic cases, single case in a new area, if not quickly controlled and outbreak can become an epidemic
Endemic
Disease or condition regularly found among particular people or in a certain area
Epidemic
Disease that affects large number of people in a community, population, region
Includes obesity, opioids
Pandemic
Epidemic that has spread to a different countries and continents
Communicability
Time an infectious agent can be transferred directly or indirectly to another person
Infectivity
Ability to produce or transmit infection
Immunogenicity
Ability of a foreign substances to provoke an immune response in the body
Toxigenicity
Ability of an microorganism to produce a toxin that contributes to the development of the disease
Pathogenicity
Ability of an organism to cause disease or harm to the host
Virulence
Degree of pathology caused by the organism, usually correlated with the ability of the pathogen to multiply within the host but may be affected by other factors
Portal of entry
How pathogen enters
Viruses
Capsid coating protects the nucleic core, can not survive without a host, simple microorganism
Pathogenic properties: binds to cell membranes, inserts into host cells, matures, new virions, bud release from plasma membrane, multiple steps in replication, may have viral latency-remain dormant for various periods of time, may invade immune response by antigen variation (drift and shift)
Fungi/yeast
Molds and yeast, large eukaryotic microorganisms, mold is aerobic yeast are facultative anaerobes, infection cause by fungi are mycoses, fungi in skin, hair, nails are dematophytes
Many are part of natural biome, cell wall is polysaccharide, highly opportunistic, phagocytes an T cells are important to limit, adapt to host by producing immunosuppressant, damage tissues with enzyme toxin secretion
Gram negative bacteria
Negative for stain, cell wall thin but duplicate, release ENDOtoxins from cell wall, causing cell lysis, lipopolysaccharide wall, ENDOtoxins can cause fever, DIC, septic shock
Gram positive bacteria
Positive for stain, single wall teichoitic acid and peptioglycan, release EXOtoxin, type 1 produces pro inflammatory cytokines, type 2 damages cell membranes, type 3 enters ell and causes damage
Listeria monocyogenes only gram + bacteria that makes ENDOtoxin
Acid fast bacilli
TB, mycobacterium, THICK cellular wall, slowing growing as nutrients have a hard time penetrating wall, long time to grow out cultures, long time to teat
Aerobic bacteria
Pseudomonas, anthrax, must have o2
Anaerobic
Do not grow when o2 is present
Facultative anaerobes
Ecology, can grin with or without o2
Staph aureus
Develop protective capsules, that delay immune response, resistance to intracellular oxidative lysis, on skin, nose adheres to surface proteins, connective tissues, endothelium, manifestations in community and hospital acquired, potential to be DRUG RESISTANT
E. coli
May exist as biofilms, normal GI flora, multipl strains, cause UTIs, travelers diarrhea, may be DRUG RESISTANT
Mycobacterium
Survives and grows within macrophages and phagolysomes, contagious, and opportunistic, resistance and can be active or latent, Develop a capsule that prevents phagocytosis, suppresses host response forms granulomas-tubercles-caseales-collagen scar-immune system response is dormant
Coronavirus
Lots of strains, droplet transmission, infectious 2-3 days before symptoms, up to 10 days after more risk if multi morbid and infection, ARB/ACE protective
Influenza
RNA virus: A, B, C, 2 surface protein, causes fever, ache, fatigue, pro inflammatory cytokines and chemokines, TNF and interferon, produced by viral cells, hemagglutinin binds to receptors on epithelia cells of throat and lungs, incubation short, long shedding time
Herpes simplex
She’d from point of infection, HS 1 oral via saliva, infection of epithelia cells, virus moves along axon of dorsal root ganglia, HS 2 genital with mucous membranes contact
Varicella/herpes zoster
Chicken pox/shingles, initial is varicella, zoster is reactivating of earlier acquired appears as vesicles along dermatone, can be transmitted mother to neonate post herpatic neuralgia, vaccine
Rubeola (classic measles)
RNA virus, resp tract amplifies in local lymphatic tissues and disseminates, very contagious, incubation 6-19 days (5 days before and 14 days after rash develops), droplet spread, hangs around for 2 hours after carrier is out of area, Maculopapular rash, head, trunk, and extremities, Koplic spots, buccaneers mucosa, RNA virus
Rubella (3 day German)
can cause congenital rubella syndrome, sensorineural deafness, congenital heart disease, pulmonary artery stenosis, retinopathy, cataract
Candida albicans
Yeast normal micro biome, opportunistic, antibiotics, immunocompromised, can be local or disseminated, resistance has developed, biofilms, cell wall adherence
Antigenic shift
2 strands of the same sort of virus come together and form a second very virulent virus such as covid 19
Antigenic drift
Small mutation over time such as the flu
Antibiogram
Published organizations list infective organisms-numbers of infections, resistance and antibiotics that organism was susceptible to
Goal of anti microbial stewardship programs
Decrease microbial resistance to abx therapy, use guidelines and antibiograms to help prescribe right drug to right bug, use upturns to change or stop abx, intentional with duration, monitor for c. Diff
Hospital acquired infection
Can be same organism as community required, but hospital usually worse hospital develops within 14 days of DC, greater than 4 days after admission, any infection in LTC, CLABSI, CAUTI, VAP, SSI, different type of pathogen, duration of tx
HIV
Types 1 and 2, 1 more common in US, blood borne pathogen via IVDU, blood products, blood, sex, mother to baby, viral envelope, proteins protruding GP120, enzymes on inside of virus, reverse transcriptase, targets CD4 cells virus binds with CD4 cells inject RNA into cytoplasm, integrates with host DNA transcription and translation results in new viral proteins production virus buds through cell membranes and infects more cells overtime infected CD4 cells eventually rupture or are killed by other cells,
HIV acute infection
Syndrome after initial infection (40-90% of infected persons) flu like symptoms, fever, lymphadenopathy, pharyngitis, rash, myalgia, n/v/d, HA, weight loss, thrush, hepatosplenomegaly, time 1-6 weeks after exposure , if known exposure antivirals should be started!
HIV testing
Gold standard combo HIV AB/AG, designed to detect early infection
If AG (-) unlikely for acute infection
If Ag(+) then HIV 1-HIV2 AB to be done
If Ag(+), HIV1/HIV2 AB differentiation immunoassay is (-), or indeterminate then viral load test should be done (CD4 test)
HIV vs. AIDS
HIV CD4 count greater than or equal to 200, no AIDS illness or history of
AIDS CD4 count less than 200, even if its once, and or presence of AIDS illness
AIDS illness
Pneumocystis jiroveci PNA (PJP), lymphoma, kaposi, toxoplasmosis, progressive multi focal leukoencephalopathy, TB, disseminated mycobacterium avian complex (MAC), oral candida infection CMV, invasive cervical CA, histoplasmosis
HIV/AIDS in kids
Baby test at 2-4 weeks if viral load (-) retest at 4 months
If no tx s/s will occur at 6 months, opportunistic infections 1st year of life, life expectancy 3 years, mm decreased by 76% if antivirals started ASAP
Fulminant
Little or no prodromal period, subclinical, brewing, difficult to treat, evolved into chronicity, individuals get very ill very quick
Antibiotic resistance
Due to inappropriate use or farming animals receiving antibiotics
Mechanisms of resistance
Inactive antibiotic
Modify the antibiotic molecule
Change the metabolic pathways to be less sensitive
Multi drug transporters prevent entrance of increase efflux of antibiotics
