M1: Intro (Book) Flashcards
Simple in structure. Prokaryotic. Has simple unicellular organisms with no nuclear membrane, mitochondria, golgi bodies & ER. Cell wall is complex.
Bacteria
Smallest infectious particles. 18-600nm. Less than 200nm can’t be seen in microscope. Contain DNA or RNA but not both.
Viruses
More complex. Eukaryotic organisms. Well defined nucleus, mitochondria, golgi bodies & ER. Dimorphic.
Fungi
Unicellular form that can replicate asexually
Yeast
Filamentous form that can replicate asexually & sexually.
Mold
Dimorphic Fungi
Histoplasma, Blastomyces & Coccidiodes “HBC”
Most complex eukaryotic microbes. Can be unicellular & multicellular. Life cycles are equally complex w/ some parasites establishing a permanent relationship with humans & others going through series of developmental stages.
Parasites
Vital for developing a differential diagnosis and an approach to control & prevention of parasitic infections
Epidemiology
Best prevention & cure for microbial disease
Innate & Immune responses
Organism that produce many manifestations of disease
Staph Aureus
Many organisms to produce the same disease
Meningitis
Arise when a person is exposed to organisms from external sources
Exogenous infection
Produced by organisms in the persons own microbial flora that spread to inappropriate body sites where the disease can ensue
Endogenous infection
Plays an important role in the diagnosis & control infectious diseases
Clinical microbiology laboratory
Based on the ability of the organism to grow, transport conditions mist ensure the viability of the pathogens.
Diagnostic tests
Study of interactions between animals and MO
Medical Microbiology
Play a critical role in human survival
Microorganism
Is in a continual state of flux determined by variety of factors
Microbial flora
Can be for a short period of time(hours or days, transiently or permanently. Do not interfere with normal body functions.
Colonization
Occurs when the interaction between microbe and human leads to a pathologic process characterized by damage of human host.
Disease
Organisms always associated with human disease
Strict pathogens
Organisms that are typically members of the patient’s normal microbial flora. Do not produce disease in their normal setting but established disease when they are introduce in unprotected sites.
Opportunistic pathogens
A large scale project has been initiated to characterize comprehensively the human microbiota and analyze its role in human health and disease.
Human Microbiome Project
Most common anaerobic bacteria
Peptostreptococcus
Most common aerobic bacteria
Streptococcus
Rarely responsible for pharyngitis
S.pyogenes
Most common organism colonizing the outer ear is
Coagulase negative Staphylococcus
The surface of the eye is
Coagulase negative staphylococci
May lead to polymicrobial disease in which anaerobes are the predominant pathogens
Chronic Aspiration
Rare cause of disease in the lower airway
C. Albicans
Cause most infections in the esophagus
Herpes simplex virus & Cytomegalovirus
Cause of gastritis and ulcerative disease
H. Pylori
Obstructed small intestine
Blind loop syndrome
More microbes are present in here that anywhere else in the human body.
Large Intestine
Is a minor member of the intestinal flora but the most common anaerobe responsible for intraabdominal disease.
Bacteroides fragilis
Most common bacteria in large intestine but are rarely responsible for the disease
Eubacterium & Bifidobacterium
Can disrupt the colonic flora & produce significant intestinal disease
Entamoeba Histolytica
Areas of the GUT that are permanently colonized with microbes
Anterior Urethra & Vagina
Are common causes of urethritis and can persist as asymptomatic colonizers of the urethra
N. gonorhea & C. Trachomatis
Common cause of vaginitis
N. Gonorrhea
More diverse and dramatically influenced by hormonal factors
Vagina
Most common organisms found on the skin surface
Gram positive bacteria
Factors that determine the population of organisms that colonize humans are complex and include
Health, hormonal state, Age, Personal hygiene & Diet “HHAPD”
Represents the total destruction of all microbes, including the more resilient forms
Sterilization
Results in the destruction of most organisms
Disinfection
Used to reduce the number of microbes on the skin surfaces
Antisepsis
Useful for removing fungi and bacteria from air or from solutions
Filtration
Vapors are effective sterilants because of the oxidizing nature of the gas
Hydrogen peroxide
Used for items involved with invasive procedures that cannot withstand sterilization procedures
High level disinfectants
Used to treat noncritical instruments and devices
Low level disinfectants
Used to clean surfaces or instruments where contamination with bacterial spores and other highly resilient organisms is unlikely
Intermediate level disinfectants
Effectiveness is greatest when applied in under pressure. Boiling heat is done.
Moist heat
Very effective form of sterilization
Autoclave
Effective if applied at a high temperature for a long duration
Dry heat
A slow process influenced by the concentration of gas, relative humidity, exposure time & temp.
Ethylene oxide sterilization
Most common commercial chlorine
Bleach
Act by disrupting lipid-containing membranes, resulting in a leakage of cellular contents.
Phenolic compounds
Used extensively as disinfectants
Halogens
Most effective halogens available for disinfection
Iodine compound
Visible light passes through a condenser, then through the object under observation and finally through a series of lenses to magnify the image. Used to examine specimens placed on glass slides.
Brightfield microscopy
Illuminates objects with parallel beams of light that move out of phase relative to each other. This allows objects to appear as 3D and useful for observing internal structures.
Phase contrast microscopy
Uses the same series as brightfield. However special condenser is used to illuminate the subject material from an oblique angle. Used to detect organisms that are too thin to be observed.
Darkfield microscopy
Uses high pressure mercury, halogen or xenon vapor lamps that emit a short wavelength of light to illuminate the object. Very usedul for organisms with natural fluorescence.
Fluorescent microscopy
Used to commonly detect bacteria, parasites & blood borne pathogens.
Differential stains
Alkali used in direct examination method
KOH
Ink darkens the background rather than the cell
India ink method
Best known and most widely used stain and forms the basis for the phenotypic classification of bacteria
Gram Stain
Used to identify blood parasites and other selected MO
Wright Giemsa
The oldest method used in acid fast stain but requires heating the specimen during the staining procedure
Ziehl Neelsen
Stain of choice because a large area of the specimen can be examined rapidly by simply searching for fluorescing organisms against a black BG
Fluorochrome method
Used to stain bacteria and fungi
Acridine orange stain
Stains the chitin in fungal cell walls
Calcofluor white
Important respiratory pathogen
Legionella
Important enteric pathogen
Campylobacter
Important bacterium responsible for STD
Chlamydia
Cause of staphylococcal shock syndrome produces disease by release of a toxin into the circulatory system.
Staph aureus
Recovery of bacteria and fungi
Blood agar
Recovery of bacteria including haemophilus & N. Gonorrhea
Chocolate Agar
Bacterial susceptibility test medium
Mueller Hinton Agar
Selective for gram negative bacteria differential for lactose fermenting species
MacConkey agar
Recovery of corynebacterium diphtheria
Cystine tellurite agar
Amplified by PCR using universal primers that recognize large groups of bacteria, and then specific sequences within the gene are amplified and sequenced to determine individual bacteria & strains.
Gene for 165 Ribosomal RNA
Can be used to determine the number of genome copies
Quantitative RT-PCR
Used to demonstrate the presence of CMV(urine) & HPV(pap smear) DNA
In situ hybridization
Used to detect viral sequences in the urine or the baby’s blood
PCR
Can be detected by RT-PCR analysis of RNA isolated from blood
Viral genome
Sensitive and specific tools to detect, identify and quantitate the antigens from microbes.
Antibodies
Recognize individual epitopes on antigen
Monoclonal antibodies
Used to detect and quantify antigens
Single radial immunodiffusion
Used to determine the relatedness of different antigens
Ouchterlony immuno double diffusion
Identifying & quantifying lymphocytes
Flow cytometer
Flow cytometer that can also isolate specific subpopulations of cells for tissue culture growth on the basis of their size & immunofluorescence.
FACS
Used to quantitate the soluble antigen in a patient’s sample. Home pregnancy test for the HCG hormone.
ELISA
Viral proteins separated by electrophoresis according to their molecular weight or charge are transferred to a filter paper
Western blot analysis
Used to quantitate the antigen-antibody complexes
RIA
Used to identify the infecting agent, evaluate the course of an infection or determine its nature.
Serology
Is the inverse of the greater dilution or lowest concentration of a patient’s serum that retains activity in one of the immunoassays just described.
Titer