Antibio Susceptibility, Phys/Chem Control, Host/Parasite Relationship Flashcards
What is MIC?
[minimum inhibitory], minimum needed antibiotic to prevent visible growth of B on/in lab media
What is MBC?
[minimal bactericidal], minimum antibiotic needed to kill a defined percent of B when a mixture of B and antibiotic are incubated together
What is measured and what are the categories in an agar disc diffusion susceptibility text?
resistant, intermediate, susceptible; measure distance from edge of disc to edge of growth
What is the E test?
gradient diffusion, larger dose of AB further out on the strip
what is the rapid AB susceptibility test?
swab on paper disc, wait for color change (colorimetric), impregnated with labeled Antibody to B lactam (or other) if color change it was hydrolyzed by B
What is antiseptic?
chemical agent used to kill microorganisms on skin, mucus membranes, or other living tissue
what is aseptic?
absence of microorganisms, usually applied to procedures in OR or micro labs which involve preventing microorganisms from reaching protected environment
What is a bactericidal?
capable of killing bacteria
What is bacteriostatic?
capable of inhibiting bacterial growth, multiplication resumes after removal
What is a disinfectant?
substance used on inanimate objects to kill or inhibit growth of microorganisms; endospores and viruses may not be destroyed; reduce or inhibit growth, but don’t sterilize
What is a germicide?
a chemical agent that kills microorganisms, bactericide, kills bacteria, sporicide kills endospores, fungicide kills fungi, virucide kills viruses and amebicide kills amoeba and protazoa
What is septic or sepsis?
presence of unwanted microorgnaisms; usually pathogens on living tissue
What is sterilization?
process of destroying all forms of microbial life (bacteria, endospores, viruses, fungi, etc) has to kill spores!!
What are methods of action of physical and chemical agents for control of microbes?
membrane damage, protein denaturation and modification, and nucleic acid damage
What are some physical controls?
heat (moist- 100C boiling some spores survive, autoclave 120C= sterile), filtration (liquids, air- HEPA 99.7% for <0.3micrometers), radiation (ionizing- xray, gamma, free radicals; nonionizing- UV thymine dimers; microwave- not sterile, heats water, spores survive)
What are some chemical controls?
surfactants, phenol and phenolics, alcohols, heavy metals and their salts, halogens, iodine, chlorine gas, hydrogen peroxide, and alkylating agents
what are some surfactants and how do they work?
soaps- ionize negative so kill, anionic detergents- bactericidal, cationic detergents- for surfaces, like quaternary ammonium, bactericidal, penetrate and puncture membrane
Give examples of phenolics and how they work.
hexylresorcinol- mouth wash, works, 30 min more come back; hexachlorophene; chlorhexidine- keeps B down for a time but stains plaque; triclosan- membrane damage
Give examples of alcohols and how they work.
ethyl- dissolve membranes, kill vegetative, evaporates fast; isopropyl- kills vegetative, evaporates, after 4-5 times should wash hands
Give examples of heavy metals, their salts and how they work.
silver- prevent and treat infections, inhibits normal B function; copper- eye gtts, washes, dressings, catheters, tubing, and air handling
What group does iodine belong to? Forms and uses?
halogen; interferes with protein structure by binding tyrosine, sporicidal, oxidizes sulfhydryls, tincture w/ potassium iodide in alcohol, iodophor (skin, longer its on more it kills)
What group does chloride belong to? Forms and uses?
halogen; gas, sodium hypochlorite (bleach), chlorine dioxide (tent sterilization of building, use marker bacteria to ensure entire building covered), chloramine (drinking water, etc, kills fish)
How is hydrogen peroxide used? effectiveness?
3% solution in home, 35% is sproicidal but can be explosive, time dependent killing; vapor- used in autoclaving room for heat sensitive instruments
What group is aldehyde in? Forms, use, effectiveness?
alkylating; formaldehyde- disinfectant, sporicidal, preservative, but carcinogenic, covalently links amino groups, proteins can’t function; glutaraldehyde- disinfectant, heat sensitive instruments, endoscopes and bronchoscopes
What group is ethylene glycol in? Forms, use, effectiveness?
alkylating; heat sensitive materials, used with nitrogens to make mixture used in sterilizer, sporicidal
What is bacteremia?
presence of bacteria in the blood
What is a carrier?
asymptomatic person harboring an infectious agent
What is a communicable disease?
transferred from one person to another by some means other than direct inoculation
What is endemic?
persistence of a disease at a low level in a defined population or geographical area
What is an endotoxin?
lipopolysaccharide moiety of gram negative cell wall
What is an enterotoxin?
exotoxin which causes GI symptoms
What is an epidemic?
increased occurrence of disease
What is an exotoxin?
protein toxin produced intracellularly and subsequently secreted by certain pathogenic bacteria
What is a fomite?
an inanimate object that may be involved in disease transmission
What is an infectious dose?
number of organism required to cause a disease
What is a latent infection?
infection in which infecting organism is quiescent, but may reactivate
What is an opportunistic pathogen?
a normally nonpathogenic bacterium capable of causing infection only under the most favorable conditions (immunosuppression)
What is a pandemic?
epidemic on a world wide basis
What is pathogenicity?
ability of microorganism to cause disease
What is pyemia?
septicemia due to pyogenic organisms which are causing multiple abscesses in the body
What does pyogenic mean?
pus-forming
What does pyrogenic mean?
capable of inducing fever
What is septicemia?
bacterial sepsis, systemic disease in which microorganisms multiply in the blood stream, producing clinical signs and symptoms
What is a superinfection?
an infection superimposed on an already existing infection or occurring after the primary pathogen is under control
What is a toxoid?
modified endotoxin treated to destroy it’s toxicity but to retains its immunogenicity
What is a zoonosis?
disease having an animal reservoir
What cell types make exotoxins? features of production, secretion and action?
gram + and -, secretion, not pyrogenic by itself not causing fever but can accompany it, super antigens can cause it, protein, heat labile (e. coli and staph), induces antitoxin, can be converted to toxoid, high potent toxicity, high specificity, no shock
What cell types make endotoxins? features of production, secretion and action?
gram -, cell must lyse to release, pyrogenic, LPS, Not heat labile, no induce antitoxin, cant be converted to toxoid, low toxicity and specificity, yes shock
what is a super antigen?
molecules that stimulate a large number of T cells by binding MHC class II and outside variable region of T cell receptor, resulting in non-specific polyclonal T cell activation
What bacteria toxin utilizes inactivation of EF2 by ADP ribosylation? disease?
corynebacterium diptheraie (dpitheria) and pseudomonas aeruginosa (abscesses)
What bacteria’s toxin blocks release of ACh? disease?
clostridium botulinum; botulism
How does E.Coli’s toxin cause diarrhea (ETEC)?
LT: elevation of cAMP, ST: elevation of cGMP
What bacterias have AB toxins? What do the subunits do?
A= active, B= binding; diphtheria, botulism, shiga toxin of shigella and E. Coli, and anthrax
What are the different invasive features?
adhesion (pili, cell wall proteins, sIgA protease), resistance to phagocytosis (capsules, cell wall proteins, etc), survival within phagocytes (obligates need it, facultative can be both, listeria, mycobacterium, legionella, salmonella, Shigella) and extracellular enzymes (protease, collagenase, lipase, collagenase, leukocidins)
What is a microbiome? importance of them?
collective genomes of all microbes on/in human body; protective barrier, nutrition, disease (prevention), and immunity (innate, modulation and regulation)
What are the major bacterial and fungal microbiota on the skin and ear?
staph epidermis, proprionibacterium acnes, staph aureus
What are the major bacterial and fungal microbiota on the eye (conjunctiva)?
haemophilus, streptococcus
What are the major bacterial and fungal microbiota in the mouth?
strep mutans, strep sallivarius, actinomyces, porphyromonas, prevotella, fusobacterium, and candida albicans
What are the major bacterial and fungal microbiota in the nose and nasopharynx?
staph aureus, strep pneumonia, haemophilus, Neisseria, staph epidermis, mycoplasma, anaerobes
What are the major bacterial and fungal microbiota in the stomach?
H pylori
What are the major bacterial and fungal microbiota in the small intestine?
bacteroides
What are the major bacterial and fungal microbiota in the colon?
bacteroides, clostridium, enterococcus faecalis, streptococcus, anaerobes, peptostreptococcus, fusobacterium, enterobacteriaceae (E. coli, Proteus, enterobacter), candida
What are the major bacterial and fungal microbiota in the vagina?
lactobacillus, E. coli, streptococcus agalactiae, gardnerella, anaerobes, mycoplasmas, candida
What are the major bacterial and fungal microbiota in the urethra?
E. coli, Staph. epidermis
What are some main cuases of disease by normal microbiota?
immunosuppression (cancer, transplant), extracorporeal devices (dialysis), cauterization, antibiotics, surgery, other diseases (AIDS, diabetes), trauma, possibly related to birth disorders
