MED SURG PN 105 Infection ATI Notes
Infection ATI Notes
Types of Organisms
• Bacteria shapes
o Round: cocci
o Rod: bacilli
• Cell wall
... [Show More] surrounding bacteria
o Gram-positive: thin
▪ Staphylococcus, streptococcus, diphtheria, listeria
o Gram-negative: thick
▪ Neisseria meningitides, neisseria gonorrhea, Escherichia coli,
salmonella
Types of Organisms: Mycobacterium
• Waxy cell wall (hard to kill)
• Most common mycobacterium
• Tuberculosis
Types of Organisms: Viruses
• Invade cells of host (intracellular parasites)
• Reproduce inside cell
• Efforts to kill viruses tend to kill host cells
• New drugs target virus-specific process
• Antibiotics ineffective
•
Types of Organisms: Fungi
• Plant-like organisms
• Live in damp, dark places
• "Eat" dead tissue
• May infect through opportunistic opening in skin
• Common skin infections are:
o Tinea pedis (athletes foot)
o Tinea corporis (ringworm)
• Antibiotics ineffective
•
Types of Organisms: Parasites
• Live in blood cells, organs, structures (intestines, vagina)
• Malaria: travels to liver
o Proliferates, infects red blood cells
• Helminths: worms in intestines
• Trichomonas: reproductive tracts
Types of Organisms: Aerobic and Anaerobic Aerobic
• Require oxygen to survive
• Mouth, gastrointestinal tract, and lungs
• Staphylococcus aureus (skin infections) and
Pseudomonas aeruginosa (lung disease) Anaerobic
• Do not require oxygen to survive
• Produces abscesses and tissue necrosis
Clostridium perfringens (gangrene) and Actinomyces (abdominal/pelvic infections)
Types of Antibiotics
• Bactericidal
o Kills bacteria directly
o Weaken cell wall (lysis)
o Bind to ribosomes, decrease protein synthesis
o Interfere with enzymes
o Eventually destroys all bacteri
• Bacteriostatic
o Kills bacteria indirectly
o Bind to ribosomes, decrease protein synthesis
o Decrease number of bacteria
o Body’s immune system kills remaining bacteria
• Antibiotics fall under two categories: Broad and narrow spectrum
o Broad spectrum
▪ Effective against a broad range of bacteria
▪ Exerts action on a structure that has similar characteristics between several different types of bacteria
o Narrow spectrum
o Effective against a narrow range of bacteria
o Exerts action on a characteristic that is specific to only one or a few types of bacteria.
Sensitivity and Resistance Sensitivity
• Determine type of bacteria.
• Obtain sample; view under microscope.
• Sample can be blood, urine, exudate from wound
• If it can’t be identified, they will Grow a sample over 24 to 48 hr.
• Expose to various antibiotics.
Resistance
• Grow in culture.
• Expose to various antibiotics.
• Broad-spectrum antibiotics create more resistant strains of bacteria.
Goal of drug Therapy for Infections
• Kill bacteria through:
• Interrupt cell-wall synthesis
• Inhibit protein synthesis
• Inhibit DNA replication/cell division
• Inhibit folic-acid synthesis
• Kill virus, parasites, fungi Four types of antibacterials:
Antibacterials: Drugs that Interfere with Cell Wall Synthesis
• Penicillins
• Cephalosporins
• Beta lactams
• Other
Penicillin
• Treats broad-spectrum infections (ear and throat, urinary tract)
• Amoxicillin: treats gonorrhea
• Addition of clavulanic acid increases spectrum of disorders (allows amoxicillin to kill bacteria)’
• Treats gram positive cocci and bacilli
Antibacterials: Drugs that Interfere with Cell Wall Synthesis
• Penicillins
• Cephalosporins
• Beta lactams
• Other
Penicillin
• Treats broad-spectrum infections (ear and throat, urinary tract)
• Amoxicillin: treats gonorrhea
• Addition of clavulanic acid increases spectrum of disorders (allows amoxicillin to kill bacteria)
Penicillin
• Prototype drug:
o Amoxicillin (Amoxil)
o Amoxicillin and clavulanic acid (Augmentin)
• Other drugs:
o Nafcillin (Unipen)
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