MICP Exam #1 – Flashcards

Koch’s Postulates

Cytoplasmic membranes are similar to eukaryotic membranes but do not contain steroids (e.g., cholesterol). 

Which are the exception to this rule?

Most have signature teichoic and lipoteichoic acids in the thick peptidoglycan wall

Which type of bacteria?

Characteristics of Lipoteichoic acids

_________ and _________ do not have cell wall and therefore cannot be differentiated by Gram stain.

Peptidoglycan polysaccharides are made up of repeating disaccharides of ________ and _________

·         Cross-linking in peptidoglycans occurs between the ______ amino acid and another amino acid at the ______ position of another chain.

In peptidoglycan synthesis passing through the membrane, activated units are attached and assembled in the _________ _________ membrane pivot.

The region of the LPS that is essential for viability of almost all gram negative bacteria

Which region of the LPS allows distinguishing of serotypes (strains) of a bacterial species and is the antigenic portion of the LPS?

Cells that lack rigid shape, assume spherical shape.

if gram-negative cell, then _________

If gram-positive, then __________ 

Cocci are what shape?

g = 

give both equations

The minimum requirements for bacterial growth are sources of:

Bacterial pathogens are almost always _________. 

This means what?

Respiration requires ___ as a terminal electron acceptor and is _____ efficient at generating energy

Coenzyme A structural groups:

Anaerobic respiration uses compounds other than oxygen (_____. _____. ______) as terminal electron acceptors, produces less ATP per mole of glucose than aerobic respiration

Glycolysis produces ___ ATP and ___ NADH

for a total of ___ ATP after ETC

The Krebs cycle produces ___ GTP, ___ NADH, and ___ FADH2

This yields a total of ___ ATP

Plasmid pTP10 is found in the clinical isolate of which bacteria

Example of a secretion pathway that is dedicated to virulence

Bacterial adherence is often mediated by adhesins:

Streptococcus mutans

            Adhesin: 

            Receptor: 

            Attachment site: 

            Disease: 

Streptococcus salivarius

            Adhesin: 

            Attachment: 

            Disease:

Bacterial invasion factors:

Ex 1: Listeria invasion and cell-to-cell spread is mediated by a protein named ______.

Which other bacteria has a homolog for protien?

Bacterial invasion factors:

Salmonella uses ____ to secrete effectors that induce “_______  ________” (macropinocytosis)

Endotoxin is released upon lysis or through “_______” of outer membrane vesicles.

Endotoxins bind to specific receptors and stimulate release of ________   (e.g., IFN-g, IL-1, TNF-a, IL-6, histamine, prostaglandins), stimulate growth of _______, and induce ______ followed by ________.

Broad classes of exotoxins

2 types of intracellular targets 

Broad classes of exotoxins

Cellular targets

1)      Hydrolyze membrane phospholipids (phospholipases). 

2)      Thiol(-SH)-activated cytolysins alter membrane permeability by binding to cholesterol.

((3)      Detergent-like activity on cell membranes; rapid rate of lysis.

These are types of ___________

3 Examples of Two-Component A-B Exotoxins with Intracellular Targets

___________ is considered to be the initiating organism and ________ the secondary invader of dental caries.

1^st colonizers come from saliva:

In pregnancy gingivitis women often suffer from advanced gingivitis associated with high levels of an alleged opportunistic pathogen in the subgingival biofilm:

Which pathogen?

Aggregatibacter actinomycetemcomitans is the only gram negative rod associated with periodontitis that is a _________ ________.

HIV-associated gingivitis and periodontitis:

Failed endontically treated teeth usually are dominated by Gram positive facultative anaerobes, and almost always include _______ ________, a species normally found in the human gut.

Infection bodies of fungi

Spores which are present on stalk-like projections or other 

Infectious bodies of fungi

 Septal fragments of the hyphae which separate to become reproductive entities

Pathogen causing Histoplasmosis 

 “Chicago disease” 

·         Pathogens remain viable in macrophages, which serve as vectors in disseminated disease to various organs

Pathogen causing Blastomycosis

Organisms phagocytize alveolar macrophages

·         Lung infection usually clears, but can form ulcerative skin and bone lesions in immunocompromised patents

Most prevalent in South America

Affects men vs women (78:1)

Primary lung infection, but can disseminate and cause mortality (16-25%) in immunodeficient.

Disseminated fungus produces painful ulcers on oral, nasal, and GI muscosa

American southwest, airborne from soil

Pathogenic organism of this disease exists only

in yeast form

 Pulmonary symptoms and radiographic lung nodules

  Second most common fungal infection in

immunosuppressed patients after candidiasis.

 Major veterinary pathogen affecting sheep and cattle

  Conidia of the fungus are inhaled from the environment

and produce localized lung infections associated with tubercular growths called mycetomas or “fungus balls”

 The pathogen also can spread via the blood and invade blood vessles causing necrosis and thrombosis, or invade organs including the brain. 

·         Aflatoxin, an extracellular protein elaborated by A. flavus (in most cases), can contaminate foodstuff, such as peanuts, and may induce hepatocellular carcinoma.

·         It is the most common opportunistic respiratory infection in late stage HIV patients and accounts for a 10-20% mortality rate in these individuals. 

The organism does not invade host cells but exists in pulmonary interstitial tissue as a sporocyst (spore case)

 Death occurs from asphyxiation. 

Treatment is administration of

trimethoprim-sulfamexoxazole or pentamidine

isethionate (both of which have side-effects) and

oxygen administration.

These two drugs form large pores in fungal cell membranes, which allow leakage of vital cell constituents. 

Drugs which affect ergosterol synthesis

Give two examples

________ is administered orrally and is taken up by the fungus, converted to 5-fluorouracil and then metabolized into compounds which are inhibitory to either RNA or DNA function. 

What is one advantage of this drug over amphotericin B

Drug that is administered orally and is active against dermatophytes, not has no effect on systemic mycoses

High-molecular-weight octapeptides that inhibit Gram-negative bacteria by interacting with the membrane and increasing cell permeability.

 Gram negative bacteria are intrinsically resistant to the hydrophobic drug ________, because of decreased uptake of the drug

What is the mechanism of action for  Chloramphenicol

Which drug has a broad similar spectrum to tetracyclines, but is not commmonly used in America?

 What is the mechanism of action for the macrolides

Most gram negative bacteria are resistant to this class of drugs that is primarily used to treat pulmonary infections

Which class of drugs are cyclic peptides that are administered as a combination of two components.

Group A and Group B

For steptogramins

Group A component binds to the ______________ and facilitates binding of the _____________.

Group B component inhibits _____ _______.

Which cleaning method removes microorganisms from liquids that would be destroyed by heat

What are some examples of these liquids

What are the 3 methods of sterilization monitoring.

Give an example of each

Which is most accurate?

One time use of critical instruments

Don't allow tissue to dry on instruments

Completely clean instruments and autoclave at 134 degrees Celcius for 18 minutes

;

These are precautions for which disease?

For which toxin does

B-subunit binds to Gb3 glycolipid receptor

A -subunit;prevents binding of aminoacyl-transfer RNA by cleaving 28S rRNA from 60S ribosomal subunit resulting in inhibition of protein synthesis