Term
| Breaking the chain: Transmission of Infection |
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Definition
Destroying: Reservoir
Blocking: Mode of Transmission, Portals of Entry and Exit
Reducing: Victim's Susceptibility |
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Term
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Definition
Nutritional status
Chronic illness
Age
Immunosuppression |
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Term
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Definition
Direct contact between reservoir and new host
-Physical
-Fecal contamination
-Airborne droplets |
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Term
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Definition
| Reservoir deposits organism on fomite (inanimate object), which transmits pathogen to new host |
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Term
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Definition
| Microorganism does not cause disease in host, but can be transmitted to others |
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Term
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Definition
Requires breaking chain of transmission
-Use antimicrobials
-Destroy nonhuman reservoirs/vectors
-Block portal exit
-Improve immune system |
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Term
| Most cost-effective method of altering pathogen susceptibility |
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Definition
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Term
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Definition
Confer immunity to host by direct exposure to pathogen
Decrease number of susceptible hosts in the population (herd immunity) |
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Term
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Definition
Acquired while hospitalized
48,000 deaths annually
catheters & ventilators
MRSA |
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Term
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Definition
| Normal flora may become pathogenic when immune system is compromised |
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Term
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Definition
Ability of a microorganism to latch onto and gain entrance into its host
-Direct penetration
-Sticks to tissue surface
-Slime layer (glycocalyx) also facilitates adherence |
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Term
| ____ help microorganism to spread or invade tissues |
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Definition
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Term
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Definition
-Prevents opsonization by antibodies
-Prevents microorganism from being phagocytized |
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Term
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Definition
| Allows microorganism to survive under harsh environmental conditions |
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Term
| Microorganism Characteristics |
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Definition
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Term
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Definition
-Microorganism consistently causes disease in all infected hosts
-Interaction between host/pathogen harms host |
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Term
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Definition
-Microorganism’s ability to mutate in response to environment changes in host
-Mutation allows successful host infection |
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Term
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Definition
| Movement of microorganisms toward favorable environment, usually toward sugar or amino acid concentrations. |
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Term
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Definition
-Individuals treated with antibiotics taking only part of prescribed dose
-Overprescription of antibiotics |
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Term
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Definition
-Polypeptides produced and released by organisms
-Very toxic |
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Term
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Definition
-Immunogenic part of bacterial cell wall that triggers a massive immune response when bacterium lyses
-Associated with gram neg. bacteria |
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Term
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Definition
| Immune response leads to cell shock and multiple organ failure |
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Term
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Definition
Borrelia: spaghetti
Treponema: corkscrew
Spirilla: flatter |
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Term
| 4 major groups of bacteria |
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Definition
1. Gliding bacteria
2. Spirochetes
3. Mycoplasmas
4. Rigid bacteria |
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Term
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Definition
Rod shaped
Escherichia coli |
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Term
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Definition
4 step process: stain, fixation, extraction, counterstain
Gram positive bacteria are already stained with crystal violet and remain purple.
Gram negative bacteria are stained pink |
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Term
| Identifying micoorganisms |
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Definition
-Are they Gram positive or negative?
-What is the morphology (rod, coccus, spiral, pleomorphic [variable form] etc)?
-Do cells occur singly or in chains, pairs etc?
-How large are the cells? |
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Term
| Bacterial infection results in death when |
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Definition
| If they overwhelm lymph nodes, bacterial emboli can cause bacteremia, microabscesses, sepsis, septic shock |
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Term
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Definition
| Systemic blood borne illness |
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Term
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Definition
-Disseminated through environment
-Reproduce by either
--Dividing (asexually)
--Combining genetic information before dividing (sexually)
-Mycoses
--Infections caused by fungi |
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Term
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Definition
1. Superficial
2. Subcutaneous
3. Systemic |
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Term
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Definition
| Strictly speaking – a chemical that is produced by one microbe and has the ability to harm other microbes |
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Term
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Definition
| Any agent that has the ability to kill or suppress microorganisms |
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Term
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Definition
-Disruption of bacterial cell wall
--Rigid cell wall/high bacterial intracellular osmotic pressure
-Inhibition of an enzyme unique to bacteria
--Sulfonamide inhibition of bacterial folic acid synthesis
-Disruption of bacterial protein synthesis
--Ribosomal differences between human and bacterial cells |
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Term
| Antimicrobial Drugs work on: |
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Definition
Cell wall synthesis
Cell membrane permeability
Protein synthesis (lethal)
Nonlethal inhibitors of protein synthesis
Synthesis of nucleic acids
Antimetabolites
Viral enzyme inhibitors |
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Term
| Four basic microbial mechanisms |
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Definition
1. Decrease the concentration of a drug at its site of action
2. Inactivate a drug
3. Alter the structure of drug target molecules
4. Produce a drug antagonist |
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Term
| Organisms With Microbial Drug Resistance |
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Definition
MRSA: Methicillin-resistant S. aureus *
VRE: vancomycin-resistant Enterococcus
MDRTB: multidrug-resistant tuberculosis |
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Term
| Mechanisms for Acquired Resistance |
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Definition
Spontaneous mutation
-random changes to microbe’s DNA
-Single drug resistance
Conjugation
-extra-chromosomal DNA is transferred from one bacterium to another
-Most common-gram neg. bacteria
-Multiple drug resistance |
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Term
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Definition
| Overgrowth of normal microbes due to treating other infection. |
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Term
| CDC’s Campaign to Prevent Antimicrobial Resistance: 12 Steps to Prevent Antimicrobial Resistance Among Hospitalized Adults |
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Definition
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Term
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Definition
-Identify organism
-Drug sensitivity of organism
-Host factors
Drug may be ruled out due to:
-Allergy
-Inability to penetrate the site of infection
-Patient variables |
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Term
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Definition
Antibiotic therapy for patients before causative organism is positively identified
(Emergency for sepsis, pre-surgery) |
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Term
| Identifying the Infection Organism |
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Definition
-Match the drug with the bug
-Gram-stained preparation
-Determining drug susceptibility
--Disk diffusion test
--Broth dilution procedure (more precise). |
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Term
| Minimum inhibitory concentration |
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Definition
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Term
| Minimum bacteriocidal concentration |
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Definition
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Term
| Antimicrobial effects of antibiotic combinations |
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Definition
Additive: 1 + 1 = 2
potentiative (synergistic): 1 + 1 = 3
antagonistic: decrease in effectiveness of 1 due to other |
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Term
| Prophylactic Use of Antimicrobials |
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Definition
Agents given to prevent infection rather than to treat an established infection
-Surgery
-Bacterial endocarditis
-Neutropenia
-Other indications |
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Term
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Definition
| inflammatory bacterial infection of the heart |
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Term
| Mechanisms of Bacterial Resistance to Penicillin |
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Definition
-Inability of penicillins to reach their targets
-Inactivation of penicillins by bacterial enzymes
-Production of penicillin-binding proteins (PBPs) that have a low affinity for penicillins (MRSA) |
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Term
| Gram-negative vs gram-positive cell envelope |
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Definition
Gram-negative cell envelope
-Three layers
-Thin cell wall and an additional outer membrane that is hard to penetrate
Gram-positive cell envelope
-Only two layers
-Relatively thick cell wall that is easily penetrated |
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Term
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Definition
-Beta-lactamases (cleave beta-lactam ring)
-Enzymes that render penicillin inactive
-Bacteria can produce a large variety of these enzymes specific for penicillins (and other beta-lactam antibiotics) |
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Term
| Classification of Penicillins (4) |
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Definition
1. Narrow-spectrum penicillins
-Pencillinase-sensitive
2. Narrow-spectrum penicillins
-Pencillinase-resistant
3. Broad-spectrum penicillins
4. Extended-spectrum penicillins |
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Term
| Assess for penicillin allergy in each patient who will be receiving penicillin |
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Definition
If history of mild reaction – consider cephalosporin
If history of anaphylaxis – avoid administration of penicillin or cephalosporins |
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Term
| 3 Types of penicillin allergy |
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Definition
Immediate (reaction in 2 to 30 minutes)
Accelerated (reaction in 1 to 72 hours)
Late (reaction takes days or weeks to develop) |
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Term
| Penicillin Allergy Treatment |
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Definition
-Epinephrine
-Respiratory support
-Prevention – skin testing |
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Term
| Penicillinase-Resistant Penicillins |
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Definition
-Nafcillin
-Oxacillin
-Dicloxacillin
-Narrow spectrum-used against penicillinase-producing staphylococcus. |
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Term
| Broad-spectrum penicillins (aminopenicillins) |
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Definition
Ampicillin (Principen)
Amoxicillin (Amoxil, DisperMox, Moxatag, Trimox)-very common drug
Adverse effects
-Rash
-Diarrhea |
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Term
| Beta-lactamase inhibitors |
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Definition
Clavulanic acid, tazobactam, sulbactam
Extends antimicrobial spectrum when combined with penicillinase-sensitive antibiotics |
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Term
| Examples of penicillin/beta-lactamase inhibitors |
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Definition
Ampicillin/sulbactam (Unasyn)
Amoxicillin/clavulanic acid (Augmentin)
Ticarcillin/clavulanic acid (Timentin)
Piperacillin/tazobactam (Zosyn) |
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Term
| Third generation cephalosporins |
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Definition
Preferred therapy for several infections
Highly active against gram-negative organisms
Able to penetrate to CSF |
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Term
| Vancomycin (Vancocin, Vancoled) |
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Definition
Drug of last resort. No longer working.
MRSA, MRSE, C.diff |
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