Microbiology Lecture 1
Transcript of Microbiology Lecture 1
![Page 1: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/1.jpg)
Dana W. Dunne, MD Course Director Assistant Professor, Department of Medicine
Section of Infectious DiseasesYale University School of Medicine
Microbiology and Infectious Diseases Physician Associate Program
![Page 2: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/2.jpg)
Course Information
• [email protected]– (203) 737-4096
• Contact Information: – Alexandria Garino, PA-C– Assistant Director for Didactic Curriculum– Yale University Physician Associate Program– (203) 785-2860 E-mail:
![Page 3: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/3.jpg)
Overview
• Medical microbiology– Morphology– Classification
• Clinical infectious diseases– Pathogenicity; virulence– Epidemiology– Clinical presentations– (Management)
![Page 4: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/4.jpg)
Overview
• Required Textbook: Medical Microbiology.
6th edition. Murray PA et al. Mosby 2009.
• Lectures:– Objective based
• Interactive Seminars:– Clinical cases
• Exams:– Exam 1 (10/21): Bacteriology,
mycobacteria– Exam II (12/21): Fungi, parasites, viruses
![Page 5: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/5.jpg)
Basic Principles and Definitions in Microbiology
1. List the 4 major groups of microbes
and their distinguishing features
2. Define colonization versus disease
3. List body systems colonized with
normal flora
![Page 6: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/6.jpg)
Microbes
1.Viruses
2. Fungi
3. Parasites
4. Bacteria
![Page 7: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/7.jpg)
Eukaryote vs Prokaryote
Eukaryote Prokaryote
Groups Algae, fungi, protozoa, plants, animals
Bacteria
Nucleus Classic membrane No nuclear membrane
Chromosomes Strands of DNA diploid Single, circular DNA haploid
Mitochondria/Golgi/ER Present Absent
Cell wall Present only fungi Complex of protein, lipids peptidoglycans
Cytoplasmic membrane
Contains sterols Does not contain sterols
Reproduction Sexual and asexual Asexual (binary fission)
Respiration Via mitochondria Via cytoplasmic membrane
Adapted from Murray , Medical Microbiology, 6th Ed.
![Page 8: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/8.jpg)
Downloaded from: StudentConsult (on 11 August 2009 07:41 PM)
© 2005 Elsevier
![Page 9: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/9.jpg)
Definition and Property of a Virus
• Filterable (smaller than bacteria)
• Obligate intracellular parasites (need the host
cell for replication)
• DNA or RNA + proteins + protein coat = capsid
• Naked or enveloped
• Range of diseases- acute to chronic
![Page 10: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/10.jpg)
Fungi• Eukaryotic (true nucleus,
mitochondria, golgi bodies, ER)
• Yeast – Unicellular, asexual reproduction
• Molds – Filamentous, asexual or sexual
• Dimorphic
![Page 11: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/11.jpg)
Parasites
• Eukaryotic
• Size range from tiny (1-2µm) to
tapeworm (10m)
• Complex structure and taxonomy
• Clinical syndromes + epidemiology
![Page 12: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/12.jpg)
Bacteria
• Prokaryotic (no nuclear membrane, etc.)
• Ubiquitous
• Cell Wall- complex
• Classified based on size, shape, spatial arrangement (chains, clusters); phenotypic and genotypic properties
![Page 13: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/13.jpg)
Bacterial Cell Wall
• Cell wall composition- one of the most important factors in bacterial species analysis and differentiation.– Gram positive- 90% of the Gram-positive cell
wall is comprised of • Peptidoglycan- THICK; essential for structure;
replication• teichoic acid- cross linked to pg• Lipoteichoic acid- lipid linked. Common on surface,
promote attachment, distinguishes serotypes
![Page 14: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/14.jpg)
http://science.kennesaw.edu/biophys/biodiversity/eubacteria/eubpix.htm
![Page 15: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/15.jpg)
Bacterial cell wall-cont.• Gram negative
• UNIQUEOuter plasma membrane: maintains structure
• lipopolysaccharide (LPS)- Endotoxin
• powerful immune stimulator; causes shock
• LPS structure is used to classify bacteria
• Lipid A – the subunit of LPS responsible for most of the pathogenic affects
• lipoproteins and the associated polysaccharides.
• Thinner peptidoglycan layer (5-10% of weight)
• Periplasmic space- transport systems
![Page 16: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/16.jpg)
http://science.kennesaw.edu/biophys/biodiversity/eubacteria/eubpix.htm
![Page 17: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/17.jpg)
Peptidoglycan structure
= NAG
= NAM
NAG= n, acetyl- glucosamine; NAM= N, acetyl muramic acid
A= d-alanine; G= d-glutamate; L- lysine
= pentaglycine peptide
A-(redder)-l-alanine
![Page 18: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/18.jpg)
Downloaded from: StudentConsult (on 11 August 2009 07:27 PM)
© 2005 Elsevier
A- Gram Positive cell wall--Thick PG layer-teichoic acid-lipoteichoic acid
B- Gram Negative cell wall-Thin PG layer
outer membrane w/ LPSperiplasmic spacecytoplasmic membrane
![Page 19: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/19.jpg)
Gram-staining
• Easy 4-step staining procedure that distinguishes the two major groups of bacteria:
– Heat fix specimen
#1- flood with Crystal violet – rinse
#2- flood with iodine (precipates crystal violet; binds PG)-rinse
#3- decolorize with acetone (gets rid of any unbound crystal
v.)
#4- counterstain with safranin- stains any decolorized cells
![Page 20: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/20.jpg)
Gram stain- cont.
• Gram positive: the crystal-violet is still present in the cell, the counter stain is not incorporated, thus maintaining the cell's purple color.
• Gram negative: Because the cell wall is high in lipid content and low in peptidoglycan content, the primary crystal-violet escapes from the cell when the decolorizer is added – pick up counterstain color which is pink
![Page 21: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/21.jpg)
![Page 22: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/22.jpg)
Figure 2-3 Gram-stain morphology of bacteria. A, The crystal violet of Gram stain is precipitated by Gram iodine and is trapped in the thick peptidoglycan layer in gram-positive bacteria. The decolorizer disperses the gram-negative outer membrane and washes the crystal violet from the thin layer of peptidoglycan. Gram-negative
bacteria are visualized by the red counterstain. B, Bacterial morphologies.Downloaded from: StudentConsult (on 11 August 2009 07:26 PM)
© 2005 Elsevier
![Page 23: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/23.jpg)
Gram-positive Cocci
• The Gram-positive cocci are grouped
together based on their Gram-stain reaction,
thick cell wall composition, and spherical
shape.
• Micrococcus and Staphylococcus
• Streptococcus and Enterococcus
![Page 24: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/24.jpg)
Bacteria
![Page 25: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/25.jpg)
Gram-Positive
![Page 26: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/26.jpg)
http://www.slic2.wsu.edu:82/hurlbert/micro101/pages/101lab3.html
![Page 27: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/27.jpg)
![Page 28: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/28.jpg)
Practical Bacterial Taxonomy
![Page 29: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/29.jpg)
Practical Taxonomy 2
![Page 30: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/30.jpg)
Practical Taxonomy 3
![Page 31: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/31.jpg)
Practical Taxonomy 4
![Page 32: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/32.jpg)
Anaerobes
• Anaerobic organisms require an oxygen free environment to grow normally. – 5-10% of all clinical infections.
• Specific Characteristics: – foul smelling discharge – necrotic tissue – gas formation in tissues or discharge
![Page 33: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/33.jpg)
World’s smelliest flower- Rafflesia
![Page 34: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/34.jpg)
Definitions
• Colonization: presence of a microorganism in or on a body site- doesn’t interfere with normal body funtions– Transient– Permanent
• Disease: interaction leads to damage to the host– Organism replicating; toxin; immune response
![Page 35: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/35.jpg)
Body Sites Normally Colonized- GI
• Esophagus – transiently colonized unless surgery or immunocompromised– Candida, Herpes simplex virus, Cytomegalovirus
• Stomach– Acidic – H. pylori
• Small Intestine: polymicrobial – anaerobes• Large Intestine: most heavily colonized
body site– Anaerobes predominate – Bacteroides – intra-abdominal dz– E. coli – extra-intestinal infections
![Page 36: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/36.jpg)
Skin
• Coagulase negative Staphylococcus (CNS), Staphylococcus aureus
• Fungi (candida, malassezia)• Don’t expect many gram-negatives
(except acinetobacter), +/- streptococci• Clostridia perfringens - 20% of healthy
adults
![Page 37: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/37.jpg)
Respiratory Tract/Head
• Mouth/oropharynx:– Anaerobes – peptostreptococci,
fusobacterium– Aerobes – streptococci, haemophilus,
neisseria, pneumococcus (Streptococcus pneumoniae)
• Ear: CNS, pneumococcus, pseudomonas
• Lower Resp tract: usually sterile, can be colonized (ie candida)
![Page 38: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/38.jpg)
Genitourinary
• Mostly sterile except distal urethra and vagina– Lactobacilli, streptococci, staphylococci– Transient colonization with gram negative organisms,
candida• Can lead to urinary tract infections (UTI) if ascends to the
bladder
– Chlamydia, N. gonorrhea – always considered accociated with disease (even if no symptoms)
• Vagina: lactobacilli, varies with estrogen status
![Page 39: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/39.jpg)
Diagnostic Methods
• Microscopy• Light (brightfield)• Darkfield- obliquely transmitted light• Phase-contrast• Fluorescent• Electron microscopy
• Transmission• scanning
![Page 40: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/40.jpg)
Microscopy
• Staining• Wet mount/KOH – no stain (direct exam)• India ink – cryptococcus- helps identify capsule• Gram stain• Wright-Giemsa- malaria, other intracellular
infections• Acid Fast- mycobacteria• Fluorescent- direct or antibody labeled
![Page 41: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/41.jpg)
Molecular Diagnosis-Detection of microbial genetic material
• DNA probes- bind to DNA sequence– Labeled (radioactive or chemical)– Tissue, fluids
• In-situ hybridization• Amplification of DNA/RNA- more sensitive
– Polymerase Chain Reaction (PCR), ligase chain rx– RT- PCR- use RT to convert RNA to DNA then
ampl.– Tissue, serum, body fluids
![Page 42: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/42.jpg)
Serologic Diagnosis-Immunologic -detection of Antibody (Ab)/Antigen (Ag)
• Serology: detect type of Ab (ex: IgM; IgG) and titer (quantification of Ab strength) – Serum; CSF; other fluids
• Detect Ag on or within cells – Immunofluorescence (fluorescent labeled Ab)– EIA – enzyme immunoassay – labeled Ab with an
enzyme
• Detect Soluble Ag (done on serum/fluid)– ELISA (enzyme-linked immunosorbent assay) –
quantitate Ag– RIA (radiolabeled immunoassays)
![Page 43: Microbiology Lecture 1](https://reader030.fdocuments.net/reader030/viewer/2022020122/5526058b4a795934498b4d8c/html5/thumbnails/43.jpg)
Conclusions
• Know the microbial classes; gram stain and
morphology classifications; key chemical reactions
• Think about the organism – host interaction, the
likelihood of colonization vs. disease, the normal flora,
potentially pathogenic flora when in the clinical
setting
• Read the text, Come to class, Learn your lecture notes
and objectives