Infections

通報

問題一覧

The time during which an infectious agent may be transferred directly or indirectly (infectious period)

Communicability

The ability to produce or transmit infection (contagious period)

Infectivity

The ability of a foreign substance, such as an antigen, to provoke an immune response in the body

Immunogenicity

The ability of a MO to produce a toxin that contributes to the development of disease

Toxigenicity

The ability of an MO to cause disease (harm the host)

Pathogenicity

The degree of pathology caused by the MO; it is usually correlated with the ability of the pathogen to multiply within the host but may be affected by other factors

Virulence

The way a pathogen enters a susceptible host

Portal or entry

A disease or condition regularly found among particular people or in a certain area

Endemic

A Disease that affects a large number of people within a community, population, or region.

Epidemic

An epidemic that’s spread over multiple countries or continents

Pandemic

A greater-than-anticipated increase in the number of endemic cases. It can also be a single case in a new area. If it’s not quickly controlled, an outbreak can become an epidemic.

An outbreak

Introduction of a disease-causing agent(s) into the body tissues (avoids immune system defense, triggers inflammatory response)

Invasion

Period of rapid cell growth and division (occurs before the immune system responds)

Multiplication

Local or disseminated presence of disease-causing agent

Spread

The presence of bacteria on a body surface (skin, mouth, intestines, or airway) without causing disease in the person

Colonization

Shapes of bacteria

Cocci, Bacilli, and Spiral

Pilus, plasmid, ribosome, cytoplasm, cytoplasmic membrane, cell wall, capsule, nucleoid, and flagellum

Structral components of bacteria

Thin cell wall but duplicate cell walls (more resistant). Release endotoxins from cell wall with lysis. Endotoxin release causes fever, hypotension, DIC, and septic shock

Gram Negative

Single cell wall. Release exotoxins. Type I; proinflammatory cytokines. Type II: damage cell membrane. Type III: enter cells and cause damage.

Gram Positive

Very thick cell wall. Slow growing due to lack of nutrient penetration of cell wall. Long time to positive cultures and long duration of abx treatment.

Acid Fast Bacilli

Must have oxygen to maintain metabolic process

Aerobic MO

Do not grow in presence of oxygen

Anaerobic MO

Grow in either (with or without oxygen), prefer aerobic

Facultative Anaerobes

Common flora of skin and nasal passages. Adheres via surface proteins->connective tissue and endothelium. Develop protective capsule, produce proteins that inhibit complement activation, resistant to intracellular oxidative lysis. Resistant forms exist. Community and hospital acquired strains.

Staph Aureus

Normal flora of GI. Various strains (HUS, UTIs, travelers diarrhea). Commonly found in biofilm of Foley catheters. Resistant forms exist.

E Coli

Survives and grows within macrophages; phagolysosomes. Develop a capsule that prevents phagocytosis. Induce anergy; suppress host response. Forms granuloma->tubercle->caseates->collagen scar->immune response->dormant. Contagious, opportunistic, resistant, and can be active or latent.

M Tuberculosis

Ability of MO to adapt genetically to antibiotics due to inappropriate use and/or farming practices

Antibiotic Resistance

Inactivate the antibiotic (beta-lactam resistance). Modify antibiotic target molecule (AZT-resistant reverse transcriptase). Change metabolic pathways to be less sensitive->resistant (sulfa drugs). Multi-drug transporters prevent entrance of or incre efflux of antibiotics (aminoglycosides)

Mechanisms of Resistance

A 10% decrease in appropriate prescribing = 17% decrease in resistance. Use guidelines and antibiograms to help you prescribe. If you culture, follow cultures and change/stop antibiotics. I’d you prescribe abx, intentional about duration, and follow for C diff (increasing abx resistance)

Antibiotic Stewardship

Timing (hospital acquired if less than 14 days after discharge, more than 4 days since admission, any time in a long-term care setting). Common infections:(CLABSI, CAUTI, VAP, SSI). Not reimbursed conditions - considerable attention focused on preventing. Different typical pathogens, need for empiric antibiotic coverage and duration of therapy.

Community and hospital acquired infections

Include mold and yeasts. Highly opportunistic- T-cells important to limit infection and produce cytokines for macrophage activation. Adapt to host environment (change morphology, survive in macrophages, produce immunosuppressive cytokines). Tissue damage (direct - enzyme and toxin secretion; indirect - inflammation)

Fungal Structure and Success

Part of normal microbiome (skin, GI, mouth, vagina). Opportunistic (antibiotics change normal flora; immunocompromised). Cell wall adhesion molecules (adhere to medial devices). Local or disseminated infections.

C Albicans

Small pathogens. Capsid coating that protects the nucleic core. Virus cannot replicate without a host (binds to plasma membrane-> inserts into host cell->matures->buds and releases from plasma membrane)

Virus Structure and Replication

Identified initially in 1960s (100s of strains). Prior severe SARS (2002-2004) and MERS (2012-localized outbreaks). Transmitted via droplet. Mild to moderate URI symptoms.

Coronavirus

Antigenic Drift

Accumulation of mutations over time

Antigenic Shift

Intermixing of RNA between two viruses

Caused by an antigenic shift. Spike proteins allow virus to infect cells. Infectious 2-3 days before symptoms and unto 10 days after developing symptoms. Cormobidites and infection. Protective factors. MIS-C in pediatric patients.

COVID-19

Family of viruses with different types (A, B, and C). Two surface proteins (hemagglutinin) that bind to receptors on epithelia cells of throat and lungs. Incubation: short, long shedding. Symptoms: fever, ache, and fatigue from release of pro-inflammatory cytokines and chemokines (TNF and interferon) produced by viral cells.

Influenza

Sheds from point of infection. Activates with fatigue, fever, and stress.

Herpes Simplex

Oral infection via saliva contact. Infection of epithelia cells. Virus moves along axon ID dorsal root ganglion

HSV-1

Gential with mucous membrane contact

HSV-2

VZV is initial infection, zoster is reactivation of earlier acquired infection. Appears as vesicles along dermatomes. Mother can transmit to neonate. Post-herpetic neuralgia with Zoster. Vaccines exist.

Herpes Varicella and Zoster

RNA paramyxovirus spread via upper respiratory tract. Amplifies in local lymphatic tissue and disseminates. Maculopapular rash: head, trunk, extremities, Koplik spots, and bucal mucosa.

Rubeola (Classic Measles)

RNA virus spread via upper respiratory tract. Maculopapular rash: head, trunk, and extremities. 1st trimester - congenital rubella syndrome (sensorineural deafness, retinopathy, cataracts, congenital heart disease, PA stenosis)

Rubella (3-day, German)

Emerged in 1980s, now considered chronic disease, two types (1 &2), transmission blood borne

HIV

More common and virulent

HIV-1

less common (west Africa), less virulent and harder to transmit

HIV-2

Virus binds to CD4->viral RNA injected into cytoplasm->viral RNA is uncoated (capsid removed)->enzyme reverse transcriptase used to make DNA from viral RNA->viral DNA travels to cell nucleus and integrates with host DNA->transcription and translation result in new viral protein production->virus buds through cell membrane and infects more cells. Infected CD4 cells will eventually rupture (apoptosis) or be killed by other T-cells->decreasing total CD4 cells.

HIV Pathogenesis

Syndrome that occurs after initial infection. Occurs in 40-90% of persons infected. Timing 1-6 weeks after exposure. FLI that lasts 3-14 days. Common symptoms: fever, lymphadenopathy, pharyngitis, rash, myalgias, diarrhea, H/A, N/V, heptaosplenomegaly, weight loss, thrush.

Acute HIV infection

Gold standard Ab/Ag test. Possible test results: if the antigen results is negative and the person is unlikely to have an infection then the person is negative; is antigen result is positive, then a HIV-1/HIV-2 Ab differentiation immunoassay should be done; if antigen result is positive and the HIV-/HIV-2 Ab differentiation immunoassay is negative and indeterminate, then HIV viral load should be done to confirm diagnosis.

HIV Testing

CD4 >/= 200 and absences of AIDS defining illness or history of one

HIV

CD4 <200 (even once, even if transient) and/or an AIDS defining illness

AIDS

Thrush, cervical dysplasia, cervical carcinoma in situ, Fever 38.5C or higher x 1 month, oral hairy leukoplakia, Herpes Zoster, ITP, PID, peripheral neuropathy, persistent vaginal yeast infections, Karposi Sarcoma, presence of any opportunistic infections.

Signs of HIV Immunocompromise

PJP, Toxoplasmosis, progressive multi focal leukencephalopathy, MAC, Kaposi’s sarcoma, lymphoma, TB, esophageal or tracheal candida infection, invasive cervical cancer, CMV infection, Histoplasmosis

AIDS Defining Illness

Neonates are infected by their mother with HIV via ___.

placenta

To diagnose HIV in children in post-natal period use ____.

HIV viral load

2 negative HIV viral load tests at 2 weeks and 4 weeks of life, is presumptive uninfected state. 2 negative HIV viral tests at 1-4 months is a definitive uninfective state

Diagnosis of HIV in post-natal period

Symptoms begin within 6 months of life. Opportunistic infection within 1st year of life. Life expectancy is typically no more than 3 years

HIV without prenatal

Patho Renal

Patho Renal

Pathophysiology

Pathophysiology

Two Clean Queens · 34問 · 2年前

Patho Immunology

Patho Immunology

34問 • 2年前

Patho Hematology

Patho Hematology

Two Clean Queens · 76問 · 2年前

Patho Hematology 2

Patho Hematology 2

76問 • 2年前

Patho Respiratory

Patho Respiratory

Two Clean Queens · 54問 · 2年前

Patho Respiratory 2

Patho Respiratory 2

54問 • 2年前

Patho Cardiovascular

Patho Cardiovascular

Two Clean Queens · 56問 · 2年前

Patho Cardiovascular 2

Patho Cardiovascular 2

56問 • 2年前

Two Clean Queens · 52問 · 2年前

Patho MSK

Patho MSK

52問 • 2年前

Two Clean Queens · 35問 · 2年前

Patho Acid Base

Patho Acid Base

35問 • 2年前

Two Clean Queens · 10問 · 2年前

Renal 2

Renal 2

10問 • 2年前

Two Clean Queens · 43問 · 2年前

Fluid Balance

Fluid Balance

43問 • 2年前

Patho Endocrine

Patho Endocrine

Two Clean Queens · 42問 · 2年前

Patho Endocrine 2

Patho Endocrine 2

42問 • 2年前

Two Clean Queens · 31問 · 2年前

Patho Shock

Patho Shock

31問 • 2年前

Two Clean Queens · 18問 · 2年前

GI 2

GI 2

18問 • 2年前

Two Clean Queens · 54問 · 2年前

Cancer

Cancer

54問 • 2年前