8. infections, antiseptics and immunization

20-300nm, intracellular, HIV-Ebola

0.8-15mcg, mostly extracellular, S.Aureus-H.pylori

2-200mcg, mostly extracellular, Candidiasis

1mm-10m, mostly extracellular, P.falciparum - tapeworm

portal of entry: route of transmission (inhalation/ingestion/contact)

communicability: ability of microorganism to spread between individuals - depends heavily on portal of entry (measles = high, HIV = low)

infectivity: ability of pathogen to invade + multiply with host

virulence: ability of viruses to cause severe disease

toxigenicity: ability of bacteria + parasites to cause severe disease via production of exotoxins and endotoxins

pathogenicity: overall ability of pathogen to produce infectious disease based on communicability/infectivity/toxigenicity/virulence

gram + = lack outer membrane but has thick layers of peptidoglycan -> easier to kill

gram - = surrounded by thin layers of peptidoglycan cell wall + outer membrane -> harder to kill

exotoxins: gram +, proteins that are excreted

endotoxins: gram -, elicit inflammatory response (fever), lipids + sugar part of cell wall

antibodies specific to exotoxins

presence of bacteria in blood -> can progress to sepsis

sepsis: immune system overreacts to infection and attacks normal tissue and organs

obligatory intracellular parasites (HAVE to go in cell)

RNA (needs extra enzyme reverse transcriptase) vs DNA viruses

infect specific cells (tropism-why virus only affects certain area of body)

may become dormant

high mutation rates

main transmission = droplet

specific tropism to receptors in airways

hemagglutinin (HA) protein = attachment + entry

M2 ion channel = uncoating

neuraminidase (NA) = budding + release (so virus can escape)

susceptible to antigenic shift

drift = minor gradual changes via mutation accumulation

shift = major sudden transformation via exchange of whole genetic segments (creates new virus strain)

main transmission = droplet

S-protein = attachment + entry (binds to ACE-2 receptors in lungs, GI and kidneys)

antigenic drift produced multiple variants with increasing infectivity but lower virulence

infection produces COVID-19 disease

mild for 80% of individuals, progress to lower respiratory tract + viral multiplication for 20%

cytokine storm + significant inflammation = acute respiratory syndrome (ARDS)

major risks factors for severe illness: age, comorbidities, immune status

asymptomatic = no clinical Sx + normal chest X-ray despite + nasal swab

mild = flu like Sx: fever, sore throat, dry cough, malaise, body aches; GI type Sx: nausea, vomiting, abdominal pain, loose stool

moderate = pneumonia like Sx: persistent fever + cough but no hypoxemia, significant lesions on CT chest scans

severe = pneumonia Sx + hypoxemia: SpO2 < 92%

critical = ARDS + multiple complications: shock, coagulation, heart failure, acute kidney injuries, encephalopathy

most common infections worldwide

mosquito transmission of plasmodium vivid or falsiporum

Sx: chills, abdominal pain, diarrhea, anemia, profuse sweating, fever

sickle cell gene protection

Mild symptom intensity, high relapse risk

severe symptom intensity, low relapse risk

transmission: sex (80%); IV drugs; mother-baby -> nurses have greatest occupational transmission risk

HIV targets CD4+ helper T cells and macrophages -> majority of untreated HIV infections develop into AIDS

RNA retrovirus -> uses RNA as genomic material, converts RNA to DNA which is then inserted into DNA of cell

last stage of HIV infection -> virus has replicated so much + destroyed so many immune cells that person is now immunocompromised

marked by increased HIV count + decreased CD4+ Th count

increased risk of opportunistic infections + cancers (this is what kills patients in the end)

major mortality cause worldwide

manifestations: herpes simplex lesions, anorexia, kaposi sarcoma lesions, cytomegalovirus retinitis vision deficits, high contagion window period (virus present but no antibodies)

idk

CNS, lymphoid, skin, GI tract, bone marrow, thymus

idk

seropositive test -> HIV antibodies

clinical latency -> may be asymptomatic for years

AIDS diagnosis -> CD4+ count < 200 cells/uL + opportunistic infections

look at graph

antiseptics: living tissues (hands)

disinfectants: non-living objects (surgical instruments)

sterilization: destruction of ALL microorganisms

sanitization: contamination meeting public health standards

germicide: kills organisms

germistatic drugs: inhibit growth

no perfect agent (safe/selective/effective/no odor....)

variable time course of action (alcohol 36s vs benzalkonium 7 mins)

most effective as prophylaxis usage on medical personal + instruments

ineffective against local infections (topical)

alcohols, iodine compounds, phenolic compounds, iodophors

aldehydes, iodophors, hydrogen peroxide, benzalkonium (both)

prototype: ethyl alcohol

main usage: fast-acting antisepsis only

antimicrobial spectrum: most pathogenic viruses + bacteria (COVID) -> dissolve membranes + protein precipitation

weakness: bacterial spores + fungi -> poor disinfectants

optimal concentration: 70% solution

contraindications: do not use on open wounds (tissue damage + coagulation mass)

miscellaneous: increases efficacy of other antiseptics

prototype: iodine

main usage: antiseptic only -> apply on skin prior to IV or blood sample

antimicrobial spectrum: all microorganisms and spores

optimal concentration: solution = 2% iodine + 2.4% sodium iodide; tincture = solution + 47% ethanol

contraindications: avoid tincture on open wounds (cuz of alcohol)

miscellaneous: oldest antiseptics, very cheap + low toxicity, only free elemental iodine kills

main usage: fast-acting antisepsis with persistent activity

antimicrobial spectrum + action: most pathogenic viruses + bacteria, low concentration -> cell membranes leaks, high concentration -> protein + nucleic acid precipitation

weakness: bacterial spores

miscellaneous: very safe, used for central venous catheter dressing, oral rinse in gingivitis patients

antimicrobial soap + water when hands are VISIBLY dirty

alcohol based handgun when hands NOT visibly dirty

active immunity: natural (infection) or artificial (vaccine)

passive immunity: natural (maternal antibodies) or artificial (monoclonal antibodies)

Live attenuated -> virus still alive but very weak, builds great immunity, NOT USED for immunocompromised (tuberculosis, measles...)

Inactivated -> virus dead, good for immunocompromised (IPV, wP..)

Subunit -> administer part of it (HepB, Hit, PCV-7..._

Toxoid -> toxic molecules that virus produces (tetanus)

RNA-based -> need RNA that codes for protein, very safe, can't produce infection (COVID)

anaphylaxis, everything else is mild (rash, fever, pain, headache...)

EMLA patch, quick IM injections

decreases vaccine efficacy + hide early adverse effects

you don't need 100% of people to be vaccinated to eradicate/protect, if most of population gets immunized then the spread of the contagious disease is contained -> important because some people cannot get vaccinated

2-18 months -> 12 total

measles, mumps, rubella, tetanus, pertussis, varicella, Hep A+B, rotavirus, polio

measles, mumps, rubella live viruse

efficacy: 97% within 2-6 weeks

adverse effects: mild -> fever, rash, pain, stiff; severe: anaphylaxis, thrombocytopenia; EXTREME caution with gelatin allergy

precautions: pregnancy, severe immunocompromised, severe febrile illness

schedule: 12 months, 18 months, boosters for HCPs

diphtheria + tetanus toxoids + acellular pertussis

efficacy: protection success -> 80-90% after 3rd dose; protection -> 6 years (pertussis) or 10 years (tetanus + diphtheria)

adverse effects: mild -> fever, rash, drowsy, anorexia; severe: convulsions, shock-like state, acute encephalopathy

precautions: contraindicated if severe illness, history of anaphylaxis reaction to previous DTaP shot

schedule: routine -> 2,4, 12 months + 4-6 years; booster DTaP -> 10-12 years

inactivated polio vaccine against polio types 1, 2 and 3

efficacy: protection success -> success in 97-100% after 2+ shots lasting years

adverse effects: mild -> local pain/reactions; potential allergic reactions to antibiotics in vaccine

schedule: routine -> 2,4, 12 months + 4-6 years

live attenuated varicella vaccine

efficacy: protection success -> 99% success with 2-dose series

adverse effects: only mild: local varicella like rash, fever, sore

precautions: pregnancy, leukemias, neomycin or gelatin allergy; AVOID aspirin for 6 weeks after -> Reyes syndrome

schedule: 1st 12 months; 2nd 18 months; 3rd 4-6 years, co administered w/MMR

Hep A = inactivated virus

Hep B = surface antigen

efficacy: Hep A = 100% success after 2nd dose; Hep B = 90% after 3rd dose

adverse effects: among safest, mild soreness + headache

precautions: Hep A = booster for risk populations; Hep B = previous anaphylaxis

schedule: Hep B given w/DTaP at 2 and 4 months

Hep A + B: 18 months + 4th grade

empty capsid proteins (antigen)

efficacy: efficient protection against cervical, vaginal + anal cancer

adverse effects: very safe, only mild

who should get it: routine vaccine for males + females recommended; before sexually active (only protects cannot treat)

precautions: pregnancy + breast feeding

schedule: 3 doses over 6 months, now part of grade 4

developed 2x a year due to rapid mutations of influenza inactivated or live-attenuated

efficacy: varies from year to year, reduces risk of contracting infection + boosts recovery

adverse effects: very safe, fever, sore

who should get it: healthcare pros, vulnerable populations

contraindications: allergic to previous one

schedule: yearly around October

moderna + pfizer: RNA based; AstraZeneca: adenovirus vector

efficacy: 80% against severe illness, 60% against infection (at least 3 doses)

adverse effects: very safe, fever, sore, fatigue, rash, rare anaphylaxis

who should get it: everyone starting at 6 months

contraindications: allergic to previous one

schedule: primary series = 2 doses 3-8 weeks apart; booster = 5-6 months after last dose/infection; more boosters if immunocompromised