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210 Cards in this Set
- Front
- Back
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What are the smallest infectious particles?
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Viruses
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The human body is inhabited by thousands of types of...
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Bacteria
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What is an endogenous infection?
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Its the most common type of infection caused by a person's own flora and usually spread from one site to another
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What does a prokaryote not contain compared to an Eukaryote?
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Its doesn't have a nuclear membrane, mitochondria, golgi bodies or endoplasmic reticulum
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How does a eukaryote reproduce?
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Asexually and sexually
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What kind of staining technique do you use for mycobacteria?
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Acid-fast staining
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Is gram staining appropriate for Mycoplasma?
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No, because there is peptidoglycan layer to stain
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What disease is associated with Staphyococcus aureus when the cocci are in clusters?
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Boils
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Does Streptococcus pyogenes (Strep Throat)cause hemolytic colonies on blood agar plates?
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Yes
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What do beta-hemolytic bacteria produce on a blood agar plate?
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The bacteria produce an enzyme that completely destroys (lyses) the RBC's in the medium and produce a clear zone
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What do alpha-hemolytic bacteria do on a blood agar plate?
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They produce an enzyme that converts red hemoglobin to green methemoglobin, thus producing a green zone
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Another name for y-hemolytic bacteria
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Non-hemolytic bacteria
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When do you use Serotyping to classify bacteria?
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When:
1. organisms are difficult to grow 2. associated with a specific disease 3. need rapid identification 4. may be used to subdivide below the species level |
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What is Serotyping?
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Its a process to identify bacteria using antibodies to detect bacteria specific antigens
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What is Biotyping?
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Its a process to identify bacteria by looking for biochemical markers. (ex. ability to ferment glucose or produce gas)
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What are the ribosomal subunits that add up to 70S?
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30S +50S
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What are plasmids?
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Extrachromosomal DNA which may confer resistance
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Gram positive bacteria have a thick or thin peptidoglycan wall?
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Thick which is essential for structure, replication and survival
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Gram negative bacteria have a thick or thin peptidoglycan wall?
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Thin (5-10%) of cell wall
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What are some characteristics of Gram-negative bacteria?
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They have a periplasmic space which can contain enzymes for transport, degradation and synthesis. They have transport proteins and LPS which can be used to identify the bacteria. The LPS can produce endotoxins that cause fever and shock in individuals
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What is fimbriae's function?
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To promote adherence and transfer genetic elements
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What is Flagella's function?
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To provide motility
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What is a capsule's function?
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Promotes adherence to tissues and barrier to toxic substances
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Name an aerobic, gram-positive cocci: specifically catalayse-positive cocci?
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Staphylococcus
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Name an aerobic, gram-positive cocci: specifically catalase-negative cocci?
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Enterococcus or Streptococcus
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Name, aerobic, Gram-positive bacilli?
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Corynebacterium
Nocardia Mycobacterium Bacillus Gardnerella Listeria |
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Name, an aerobic, gram-negative cocci?
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Moraxella
Neisseria |
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Name an aerobic, gram-negative bacilli?
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Enterobacteriaceae:
Citrobacter Enterobacter Escherichia Klebsiella Morganella Proteus Salmonella Serratia Shigella Other: Vibrio Aeromonas Campylobacter Helocobacter pseudomonas Haemophilus Pasturella Acinetobacter Burkholderia Stenotrophomonas |
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Name an anaerobic, gram-positive cocci?
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Peptosterptococcus
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Name an anaerobic, gram-positive bacilli?
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Actinomyces
Bifidobacterium Clostridium Lactobacillus Propionobacterium |
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Name an anaerobic, gram-negative bacilli?
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Bacteroides
Fusobacterium Prevotella |
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These are some random anerobic bacteria...
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Mycoplasma
Borrelia Treponema Chlamydia Coxiella Ehrlichia Rickettsia |
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What can viruses not make?
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Energy and proteins, they rely on a host for that
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What is the envelope on the outside of a virus called?
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Capsid which provides a packaging, protection and delivery
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What is a viral genome made out of?
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RNA or DNA but not both
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How does a retrovirus work?
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It makes DNA from an RNA template
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Is the DNA of a virion single or double stranded?
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Can be both, also DNA is linear or circular
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Is the RNA of a virion single or double stranded?
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Can be both, also RNA is segmented into pieces
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What is a naked capsid?
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It helps a virus to withstand harsh conditions and provides a rigid structure
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Capsid viruses
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1. spread easily
2. can dry out and survive 3. can survive the pH of the stomach and chemicals 4. antibodies against them may not be sufficient for immunoprotection |
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Enveloped Viruses components:
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Membrane lipids, proteins and glycoproteins
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Enveloped Viruses properties:
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1. Environmentally labile
2. Modifies the cell membrane during replication 3. Is released by budding and cell lysis |
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Enveloped Viruses consequences:
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1. Must stay wet
2. Cannot survive in the GI tract 3. Spread in fluids, respiratory drops, blood and tissue 4. Does not need to kill the cell to spread 5. May need antibody and cell-mediated immune response 6. Elicits allergic rxn and inflammation |
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Is the DNA in DNA viruses labile?
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No the DNA does not change and remains in host cell nucleus.
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DNA virus properties:
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- viral genes must interact with host
- viral DNA resembles the host's DNA - larger viruses encode teir own polymerases and have more control over replication |
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Name a capsid DNA virus (2)
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Papiloomavirus
Adenovirus |
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Name an enveloped DNA virus (6)
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Smallpox
Herpes simplex - Herpes Zoster Varicella-zoster Epstein-Barr Cytomegalovirus Hepatitis B |
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Is the RNA in RNA viruses labile?
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Yes
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RNA virus properties:
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- RNA is labile
- most replicate in cytoplasm - must encode own RNA polymerase - prone to mutation |
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Capsid RNA viruses (3)
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`Rhinoviruses
Poliovirus Hepatitis A |
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Enveloped RNA viruses (11)
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Rubella
Yellow Fever Hepatitis C Coronavirus Rabies Ebola Influenza A, B, C Parainfluenza Measles Mumps Respiratory syncytial virus (RSV) |
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Is Fungi prokaryotic or eukaryotic?
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Eukaryotic
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What is a Saprobe?
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Fungi living on dead or decaying matter
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What is a Symbiont?
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A fungi organism living together with another organism to live for a mutual advantage
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What is a commensal?
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Two organisms live together, one benefits and the other neither benefits or is harmed...this is referring to fungi
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What is a parasite?
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Organism that lives on a host and causes harm to the host
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What are the structural components of fungi?
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1. complex cytosol
2. Cell membrane contains ergostero, glycoproteins, phospholipids 3. cell wall contains chitin, glucan and other polysaccharides |
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Are yeasts mutlicellular?
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No they are unicellular
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Yeast examples
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Candida
Cryptococcus |
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Yeasts reproduce asexually or sexually?
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Asexually by budding or fission
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Hyphae are made of what?
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branching, threadlike tubular filaments
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What are the reproductive structures of the Hyphae called?
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Conida which are the asexual reproductive structures on the hyhae that are easily airborne
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Name some Hyphae?
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Aspergillus
Fusarium Rhizopus Mucor |
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What is a dimorphic example of a fungi?
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Histoplasma
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What are some non-specific tests for confirming microbial infection?
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WBC, ESR and C-reactive protein tests
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Colonization
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1. presence of normal flora
2. presence of microbe without active infection |
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Infection
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1. impaired host defnse
2. translocation of normal flora to normal sterile sites |
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Contamination
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- positive culture from a normally sterile site without presence of actual infection
- usually due to a technique break in transfer of culture |
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Cultures from specific sites:
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- Blood
- Sputum - Wounds - Urine |
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Are antigen detection methods faster than cultures?
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Yes they have rapid turn around periods of a half to full hour
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Nucleic acid probe assays
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- identify short nucleotide sequences unique to an organism
- for slow growing organisms |
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What 2 bacteria are nucleic acid probe assays good for detecting?
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- N. gonorrhoeae
- Mycobacterium tuberculosis |
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PCR
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- rapid turn around time
- nuceic acid amplification assay - very sensitive - good for HIV and Herpes viruses |
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Is Staphylococcus gram + or - ?
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Its Gram positive cocci
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Is Staphylococcus aureus coagulase-negative or positive?
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Coagulase-positive
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Are capsules important for Coagulase negative Staphylococcus?
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Yes
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What do Teichoic acids do?
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Mediate attachment
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What does protein A do?
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reduces antibody-mediated response
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What kind of cytotoxins are there?
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alpha, beta, delta and gamma
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What toxin is associated with community-acquired MRSA?
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Panton-Valentine Leukocidin
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What toxin is associated with Staph scalded skin syndrome?
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Exfoliative toxins
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What toxins cause food poisoning?
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- enterotoxins resistant hydrolysis by GI enzymes
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What is the enzyme associated with clumping factor?
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coagulase
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What type of inmate shall not be placed in the Safety Chair?
A. Homosexuals B. AIDS Patients C. Pregnant D. None of the above |
C. Pregnant
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Staphylococcus colonizes where?
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- skin, nasopharynx, oropharynx, GI tract, Urogenital tract
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Staphylococcus aureus associated diseases:
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1. Scalded Skin Syndrome
- large blisters and no scarring 2. Food poisonings 3. Cutaneous infections - impetigo, folliculitis, furuncles, carbuncles - wound infections or cellulitis 4. Endocarditis - secondary to infection acquired during surgical procedure or with use of a contaminated IV catheter - endocarditis is nonspecific to life threatening(antibiotics and possibly surgery are necessary) 5. Pneumonia and empyema 6. osteomyelitis - hematogenus dissemination to bone - secondary infection due to trauma or extension of disease from an adjacent area 7. Septic Arthritis - from getting intra-articular injections |
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Staphylococcus coagulase-negative
associated diseases: |
1. Endocarditis
2. Catheter and Shunt wounds 3. Prosthetic Joint Infections 4. Urinary Tract Infections 5. Methicillin-resistance - MecA gene (PBP2a) 6. Vancomycin resistance |
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Prevention and control
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- cleansing of wounds
- disinfectants prior to surgery - handwashing - covering of exposed skin surfaces - isolation -decolonization |
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Is Streptococcus gram + and - ?
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Gram positive cocci
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Streptococcus has what kind of hemolytic patterns?
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alpha, beta and non-hemolytic
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Streptococcus gram-positive cocci are usually arrange in...
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pairs or chains
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Streptococcus pyogenes are in what arrangment and have what hemolytic activity?
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They come in cocci in chains and are beta hemolytic
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Streptococcus pyogenes can cause a rash called...
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Scarlet fever from produced pyrogenic exotoxins, superantigens release cytokines
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Where does Streptococcus pyogenes colonize?
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skin, oropharynx, respiratory droplets
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Diseases from Streptococcus pyogenes:
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1. Pharyngitis
2. Scarlet Fever 3. Pyoderma (impetigo) 4. Erysipelas 5. Cellulitis 6. Necrotizing fasciitis 7. Streptococcal toxic shock syndrome 8. Bacteremia 9. Rheumatic fever |
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Does Bacteremia have a high mortality rate?
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Yes up to 40%
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What disease is associated with strawberry tongue?
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Scarlet Fever - known to have a yellowish white coating on tongue
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Pyoderma (impetigo) can be caused by what bacteria?
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Streptococcus pyogenes and S. aureus, pustules which rupture and crust over
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What is Erysipelas?
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Its a raised skin infection of upper dermis + lymphatics
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What is Cellutitis?
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Its an infection of the deep dermis and subcuteaneous fat, distinction between infected and non-infected tissue is not clear
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What is necrotizing fasciitis?
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Deep tissue infection causing extensive destruction of skin, fascia, muscle and fat
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What is streptococcal toxic shock syndrome?
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Its shock and organ failure, bacteremic with most patients that have necrotizing fasciitis
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What arrangement does Streptococcus agalactiae come in?
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forms chains and is beta-hemolytic, encapsulated
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The very young are at increased risk of disease from this type of bacteria?
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Streptococcus agalactiae
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Clinical diseases of Streptococcus agalactiae:
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1. Early onset neonata disease
2. Late onset disease 3. Infections in pregnant women 4. infections in men and non-pregnant women |
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What is a group B strep screening?
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Its an antigen detection method using blood, urine, or CSF for Strep. Its too insensitive for screening mother prior to delivery. Selective media required and most appropriate screening method.
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Does a group B strep screening need a selective media?
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Yes
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How many species are there for Viridans Streptococci?
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24 - anginosis, bovis, mitis, mutans, salivarius
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What hemolytic activity does Viridans Streptococci?
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Alpha and non-hemolytic
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Where does Viridans Strep colonize?
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oropharynx, GI and GU tract, not on skin usually
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Clinical diseases of Viridans Streptococci?
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Dental caries,
Endocarditis Intra-abdominal infection |
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What shape is Strep pneumoniae?
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oval or lancet shaped and arranged in pairs or short chains
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Is Strep pneumoniae encapsulated?
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Yes, its gives it antiphagocytic protection and antibodies against type-specific capsular antigens
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Where does Strep pneumoniae colonize?
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Nasopharynx, oropharynx, spreads to lungs, sinuses and ears
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Risk factors for developing pneumonia:
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- antecedent viral disease
- COPD, acoholism - HF, DM - Chronic renal disease |
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Diseases associated with Strep pneumoniae?
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pneumonia
siusitis and otitis media meningitis bacteremia |
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What is the mortality rate related to menigitis from strep pneumoniae?
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80%
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What is pneumonia?
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most common pathogen in CAP, high fever, high WBC count, cough/sputum production, chest pain and poor oxygenation, generally localized in lower lobes of lungs
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How is sinusitis and otitus media spread?
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Sinusitis and OM are usually preceded by viral infection, sinusitis affects all ages where OM mostly occurs in younger children
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What is meningitis?
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Results from bacteremia, ear r sinus infections or head trauma, leading cause of meningits in children and adults with high morbidity
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What kind of bacteria are entercococcus? aerobic or anaerobic? Gram + or - ?
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Aerobic gram + cocci, also facultative anaerobes
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Enterococcus are referred to as Group what?
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Group D
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Does enterococcus produce a potent toxin?
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No
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What are the most common types of enterococcus (2)?
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Enterococcus faecalis
- large amounts in stool and commin in GI tract Enterococcus faecium - higher likelihood of resistance and found in the GI and GU tracts |
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Clinical diseases of Enterococcus?
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Nosocomial infections of the UT, bloodstream, endocarditis, intra-abdominal infection and wound infections.
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What bacteria is one of the leading causes of nosocomial infections?
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Enterococcus
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What kind of bacteria are enterobacteriaceae?
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Aerobic Gram negative bacilli, also facultative anaerobes
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Where are enterobacteriaceae found?
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Found in soil, water vegetation and normal intestinal flora
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Enterobacteriaceae are oxidase positive or negative?
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negative and usually reduce nitrates to nitrites
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Examples of lactose fermenting enterobacteriaceae?
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1. Escherichia
2. Klebsiella 3. Enterobacter 4. Citrobacter 5. Serratia |
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Examples of non-lactose fermenting Enterobacteriaceae?
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1. Proteus
2. Salmonella 3. Shigella 4. Yersinia |
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Do Enterobacteriaceae produce endotoxin?
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Yes, and produce systemic manifestations including shock, fever and death.
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What are the exotoxins of E. coli?
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Shiga toxin and Hemolysin
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Clinical diseases of E. coli?
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1. Septicemia
2. UTI 3. Neonatal meningitis 4. Gastroenteritis 5. Intra-abdominal infection |
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The food poisoning from Salmonella comes from ingesting what foods?
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Poultry, eggs, dairy, contaminated food and possibly fecal oral spread
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Salmonella is protected from the stomach acid from what gene?
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ATR gene
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Clinical diseases of Salmonella (4)?
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1. Enteritis
2. Septicemia - highest risk with AIDS patients 3. Enteric fever - typhoid fever 4. Asymptomatic colonization |
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How Shigella spread?
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Mainly by the fecal-oral transmission from contaminated hands
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Clinical diseases of Shigella?
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Gastroenteritis and Asymptomatic carriage
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What kind of bacteria is Pseudomonas?
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Aerobic Gram-negative bacilli
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Does Pseudomonas ferment lactose?
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No
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Is Pseudomonas oxidase-negative?
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Its oxidase positive
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Where is Pseudomonas found?
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Found in soil, vegetation, water and decaying matter or hospital environment
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Is it normal to find Pseudomonas in the human body?
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No
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Is antimicrobial resistance common with Pseudomonas?
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Yes very common
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What does the virulence factor mucoid exopolysaccharide capsule of Pseudomonas do?
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- anchors bacteria to cell walls and mucin
- acquired resistance also is common |
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What are virulence factors of Pseudomonas?
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1. Adhesins - pilli
2. Mucoid exopolysaccharide capsule 3. Endotoxin 4. Exotoxin A 5. Elastases |
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What does elastase do? (Virulence factor of Pseudomonas)
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Degrades elastin which damages lung tissue, causes immune suppresion and hemorrhagic lesions
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Clinical Diseases of Pseudomonas?
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1. Pulmonary Infections
2. Primary skin infections 3. UTIs 4. Ear infections 5. Eye infections 6. Bacteremia 7. Endocarditis |
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How to diagnose Pseudomonas?
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1. Grows easily on common media
2. colonies have green pigmentation 3. sweet grapelike odor |
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Similar species to Pseudomonas?
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1. Burkholderia
2. Stenotrophomonas maltophilia 3. Acinetobacter 4. Moraxella |
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What kind of bacteria is Haemophilus?
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Gram-negative bacilli or coccobacilli
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Examples of Haemophilus?
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1. H. influenzae
2. H. parainfluenzae 3. H. ducreyi |
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Does the cell wall of Haemophilus contain LPS and endotoxin?
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yes
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What bacteria has many strains of a polysaccharide capsule?
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Haemophilus
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Patient at greatest risk for getting a Haemophilus disease?
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- those with inadequate levels of protective antibody
- depleted complement - spleenectomy |
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What is the Hib vaccine?
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Its a vaccine against H. Influenzae type B
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Clinical diseases of Haemophilus?
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1. Meningitis
2. Epiglottitis 3. Cellulitis - reddish blue patches 4. arthritis 5 otitis, sinusitis, lower resp tract infection 6. Conjuctivitis |
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To elminate H. Influenza type B carriage in children at high risk of disease, what must be done?
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Antibiotic prophylaxis
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Legionella are what type of bacteria?
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Gram-negative bacilli
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Are Legionella typical?
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They are atypical
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Does Legionella stain well?
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No, its stains poorly with conventional dyes, but a silver stain can be done
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What bacteria is capable of replication in alveolar macrophages?
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Legionella
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Where is Legionella found?
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Found in natural bodies of water, air conditioners, showers and hot tubs
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Legionella can survive hot temperatures and disinfectants but what are they protected by?
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Parasitizing amoeba
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Legionella causes appx how many cases of infection per year?
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10,000 to 20,000, elderly at greatest risk for disease
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Clinical diseases of Legionella
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1. Pontiac Fever
2. Legionnaire's disease - mortality rate 15-20% |
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What lab diagnosis test do you use for Legionella?
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DFA - direct fluorescent antibody test
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What culture do you use for Legionella?
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specific culture media required with supplemented L-cysteine
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Where is the antigen found to test for Legionella?
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Urine
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What is peptostreptococcus?
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All anaerobic cocci
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Where does peptostreptococcus colonize?
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oral cavity, GI and Gu tract and skin
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Clinical diseases of Peptostreptococcus?
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1. Sinusitis and pleuropulmonary infections
2.Intra-abdominal infections 3. Endometriitis, pelvic abscesses, salpingitis 4. Cellulitis and soft tissue abscesses 5. Bloodstream infections |
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What type of bacteria is Clostridium?
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Anaerobic gram-positive bacilli capable of forming endospores
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Where is Clostridium found?
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Soil, water, sewage and normal GI flora
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What is Clostridium perfringens produce that causes massive bleeding?
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alpha toxin
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Does C. perfringens produce spores?
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Yes
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C. perfringens diseases?
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1. Soft tissue infections
- cellulitis - fasciitis - myonecrosis or gas gangrene 2. food poisoning short course 3. Septicemia |
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What is the major effect of neurotoxin associated with C. tetani?
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Causes tetany and block release of inhibitory NTs
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What Clostridium causes the biggest challenge in clinical practice?
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C. difficile
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C. Difficile problems
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Causes mild diarrhea to severe pseudomembranous colitis and toxin production
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C. difficile toxins
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Enterotoxin A
- causes release of cytokines, hypersecretion of fluid and hemmorrage Cytotoxin B - causes depolymerization of actin with loss of cellular exoskeleton |
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Can C. difficile be found in healthy people?
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Yes
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When does C. diff develop?
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When patients are receiving antibiotics
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What are the relapse rates of C. diff?
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20-30%
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Name 3 anaerobic gram-negative bacilli?
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1. Bacteroides fragilis
2. Fusobacterium 3. Prevotella |
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Do anaerobic gram - bacteria normally inhabit the body?
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Yes in large numbers, especially the GI tract
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Clinical diseases of Anaerobic gram - bacteria?
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1. RTIs- Prevotella and Fusobacterium
2. Brain abscesses - Fusobacterium and Prevotella 3. Intra-abdominal infections - bacteroides fragilis 4. Gynecologic infections - Prevotella 5. Skin and soft tissue infection - bacgeroides fragilis 6. Bacteremia - bacteroides fragilis and fusobacterium |
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Lab diagnosis of Anaerovic gram - bacteria takes how long?
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2 days
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Anaerobic gram - bacteria are beta-lactamase resistant?
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Yes its common
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Mycobacteria are what type of bacteria?
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Aerobic weakly gram + bacilli
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Mycobacteria are very resistant to common disinfectants and antibiotics because of?
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lipid-rich cell wall
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How fast do mycobacteria grow?
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Very slow - divide every 12-24 hours
- most species require 10-14 days of incubation with special formulated broth media |
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Mycobacteria is most known for association with what disease?
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TB
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How is Mycobacterium tuberculosis acquired?
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Through inhalation of aerosolized particles, the disease results from host cullular immune response to infection - huge amounts of activated macrophages can form granulomas
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One third of the world's population is infected with this TB bacteria, what is it?
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Mycobacterium TB
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How is Mycobacterium spread?
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close person to person contact
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Clinical diseases of Mycobacterium TB?
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Pulmonary
- replication ceases in 3-6 weeks - progression of disease depends on infectious dose and immune competence of patient -HIV patients very susceptible - sign of infection are weight loss, cough, sputum change with blood |
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Treatment for TB
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Four drug regiment initially:
1. INH + rifampin 2. add 2 agents until suceptibilities known - directly observed therapy may be necessary - long duration of therapy (6-9 months) needed to prevent resistance |
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How is Mycobacterium avium comples(AIDS condition) acquired?
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Primarily via ingestion of contaminated water or food
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What patients are at highest risk for MAC?
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AIDS patients
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Clinical diseases of MAC?
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Dissemintated infection - no organ is spared and chronic localized pulmonary disease
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Drug treatment for MAC?
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3 drug regimens:
(Macrolide + ethambutol + rifabutin) |
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What treatment would you probably use for AIDS patients infected with MAC?
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Prophylaxis when CD4 count is less than 50 cells/mm3
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What is the smallest free-living bacterium?
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Mycoplasma pneumoniae
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Does Mycoplasma pneumoniae have a cell wall?
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No, so you can't identify through gram staining
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What group of people does mycoplasma pneumoniae infect?
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School age children and young adults
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How is Mycoplasma pneumoniae transmitted?
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Through nasal secretions
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Clinical diseases of Mycoplasma pneumoniae?
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1. Upper resp tract infections
2. Lower resp tract infections - tracheobronchitis which occurs in less than 10% of patients - atypical/walking pneumonia |
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Lab diagnosis to identify Mycoplasma Pneumonia?
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Does not stain well, so cultures can be isolated from the throat or bronchial washings, collected sputum. Serologic testing and cold agglutinin measure IgM and IgG antibodies
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