MICRO Exam 4 Flashcards
Antifungals
Attack fungal infections
Antiprotozoals
Attack protozoans
Quinine
Extracted from the bark of a cinchona tree used for 100s of years but now largely replaced by synthesized quinolines like chloroquine to reduce parasite resistance.
Azole
broad-spectrum antifungal agents with complex ringed structure that inhibit ergosterol and cell membrane synthesis
Contains 2 ph groups, a ph group with a Cl and a pentane with two N
Antibacterials
Bacterial infection that is treated with an enormous diversity of compounds.
Antivirals
Selective toxicity is almost impossible due to the obligate intracellular parasitic nature of viruses
1. Block penetration into the cell
2. Block replication, transcription, or translation of genetic material aka Acyclovir
3. Prevent maturation of viral particles
MIC
Minimum inhibitory concentration
Minimum amount of antibiotic needed
Antibiotic resistance
Microbes become resistant to certain treatments of antibiotics
Intrinsic resistance
cells have an innate or natural resistance to a drug
Tolerance or situational resistance
A usually susceptible cell is in a environmental situation where it is no longer susceptible to the drug
Acquired resistance
permanent, genetically encoded resistance to an antimicrobial drug
Human opportunistic pathogen
Can cause disease by penetrating a break in the skin or through mucous membranes
Nosocomial
Hospital acquired infection
Mech of resistance to beta lactams
- Alternative Enzymes (PBP2A)
- Beta-Lactamases
PBP2A
A new transpeptidase that helps form the bacterial cell wall
Beta-Lactamases
Enzymes produced and secreted by bacteria that degrade all beta-lactam structures.
Clavulanate
Inhibitor of beta-lactamases
Summary of Resistance Mech for Acquired resistance
- Inactivating enzymes (Inactivates AB)
- Alternative enzyme (Diff enzyme used)
- Target Alteration (Changes binding site)
- Decrease uptake (lBlocks entry)
- Increase flux (Flushes AB out)
Human microbiota
All the microbes that can naturally reside on or within human tissue or fluids
Microbiome
Describes the collective genomes of the microbes that reside in an ecological niche
Sites that harbor microbes
Skin and mucous membranes
Upper respiratory tract
GI Tract
outer opening of the urethra
External genitalia
Vagina
External ear and canal
External eye
Sites that don’t harbor micorbes
All internal tissues and organs
Heart
Liver
Kidneys and bladder
Brain and spinal cord
Muscles
Bones
Ovaries/Testes
Glands
Middle and Inner Ear
Internal Eye
Fluids within an organ or Tissue
Blood
Urine in kidneys, ureters, and bladder
cerebrospinal fluid
Saliva prior to entering the oral cavity
Semen prior to entering the urethra
Axenic Condition
Germ-free animals as a way to investigate how essential the microbiota are to human life
Importance of the Microbiota
- Microbiota provide essential nutrient
- Lead to development of health immune system
- Microbiota can protect against pathogens
Course of infection
- Contact- Microbe adheres to body surface
- Colonization with microbiota
- Invasion of microbe cross lines of defense toxins or virulence factors can assist
- Infection- Microbe growing in what should be sterile tissue/fluids which leads to a disease state
- Treatment or human defenses fail
Alternatively
Infection clears
Infection
Microbe penetrates host defenses, and invades sterile tissues/organs and multiplies to cause disease
Disease
Defined as any deviation from health
Infectious disease
Infection causes damage/disruption to tissues/organs by microbes or their products
Pathogens
Organism capable of causing disease in healthy personas with normal immune defenses
Opportunistic pathogens
Not pathogenic to a normal health person, also organisms causing disease when the host’s defenses are compromised or when they grow in a part of the body not natural to them
pathogenicity
Ability of microbe to establish itself in the host and cause damage/disease
Virulence
The degree to which an organism is pathogenic. It determines a microbe’s ability to establish itself and cause damage
Virulence factor
Genetically-encoded, structures, characteristics or products of the microbe that contribute to the infection or disease state
Examples:
Invasin, BI antigen, endotoxin, exoenzymes, excreted enzymes
Toxin
Also known as exotoxins, a specific chemical products of microbes, promote infection and disease by directly damaging host tissues and disabling the immune system
Exotoxins
Proteins with a strong specificity for a target cell and extremely powerful, sometimes deadly effects, generally by damaging the cell membrane and initiating lysis or disrupting intracellular function
Symptom
Subjective evidence of disease as sensed by the patient
Asymptomatic
Infections that do not produce overt indications, no noticeable symptoms even though the microbe is active in the host tissue
Syndrome
When a disease can be identified or described by a defined collection of signs and symptoms
Signs
Evidence of disease by an observer
Incubation period
Time from initial contact with the infectious agent to the appearance of the first symptoms; the agent is multiplying but the damage is insufficient to cause symptoms; several hours to several years
Prodromal stage
vague feelings of discomfort; nonspecific complaints
Period of invasion
Multiplies at high levels, becomes well-established; more specific signs and symptoms
Convalescent period
As person begins to respond to the infection, symptoms decline. In the event that the patient does not recover and dies the infection is considered terminal.
Communicable
Capable of spreading person to person
Contagious
How “easy” a infectious disease spreads from person to person
Acute infection
Rapid onset with severe but short-lived effects (hours, days, weeks)
Chronic infection
Infections that progress and persist over long periods of time (months, years, lifetime)
Latent infection
The casual pathogen goes dormant for extended periods of time with no active replication and therefore no host symptoms and signs.
Portal of entry
Where the microbe must enter or there is a lesser chance of infection
(Respiratory is the greatest portal of entry)
Infectious does
Minimum number of microbes to cause disease
Adhesion
Microbes gain a stable foothold at the portal of entry; dependent on binding between specific molecules on the host and pathogen
Phagocytes
Engulf pathogens and destroy them by means of enzymes and antimicrobial chemicals.
Local
Localized on a spot
Systemic
Throughout the body
Focal
Growing in one location, causes an infection elsewhere (breaks loose and disseminates)
Polymicrobial
Many microbes causing infections
Primary/Secondary
First infection was followed by a second infection of different microbes
Latency
After the intial symptoms in certain chronic disases, the microbe can periodically become active and produce a recurrent disease; person may or not may shed it during the latent stage
Carrier
An individual who inconspicuously shelters a pathogen and spreads it to others.
Asymptomatic carrier
Shows no symptoms of the infection and carries the infection
Incubation carrier
spread during the incubation period
Convalescent carrier
Recuperating without symptoms