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MICROBIOLOGY
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Identify 3 components of both gram positive and negative bacteria. - ANSWER>>>-Cell wall
- Capsule
- Plasma cell membrane Compare/contrast gram (+) and gram (-) bacteria - ANSWER>>>Gram (+)
- thick peptidoglycan
- small periplasmic space
- Teichoic acid Gram (-)
- THIN peptidoglycan
- LPS
- Porins
- Large periplasmic space Plasmids carry genes for? - ANSWER>>>1. Antibiotic resistance
- Resistance to heavy metals (Hg, Ag)
- Resistance to UV light
- Pili
- Exotoxins Bacterial shapes: cocci - ANSWER>>>- diplococci (pair)
- streptococci
- tetrad (4)
- staphylococci
- Sarcina (cube of 8) Bacterial shapes: Rods (Bacilli) - ANSWER>>>-chain of bacilli
- flagellate rods
- spore former Bacterial shapes: Spirals - ANSWER>>>-Vibrios
- Spirilla
- Spirochaetes The shape of a bacterium is determined by its _____. - ANSWER>>>rigid cell wall Smallest and largest bacteria - ANSWER>>>Smallest: Mycoplasma Largest: Bacillus anthracis Bacteria is a prokaryote with the following characteristics : ______ - ANSWER>>>-no nucleus or membrane-bound organelles
- chromosomes and plasmids freely float in cytoplasm Function of cells wall - ANSWER>>>• Provides structural support
- Made of peptidoglycan (polysaccharide)
- protects against osmotic pressure
- penicillin, vancomycin and cephalosporin acts here Outer membrane of gram (-) bacteria has Lipid A which is _____ - ANSWER>>>endotoxin What are bacterial ribosomal subunits? - ANSWER>>>50 s and 30s A periplasmic space in gram negative is ____ - ANSWER>>>bigger Fate of Beta lactamases in gram (+)/(-) bacteria - ANSWER>>>Gram positive flushes out beta lactamases from small periplasmic space Gram negative will store beta lactamases in its bigger periplasmic space Porin channels made up of proteins are outside of ____ bacteria. - ANSWER>>>gram negative Most antibiotics that pass through porin channels (made of proteins) are ______. - ANSWER>>>Hydrophilic Function of polysaccharide - ANSWER>>>major surface antigen frequently used in lab diagnosis function of teichoic acid - ANSWER>>>major surface antigen rarely used in lab diagnosis; found in gram POSITIVE bacteria Nonessential components of bacteria - ANSWER>>>-capsule
- pilus or fimbria
- flagellum
- spore
- plasmid
- granule
- glycocalyx function of ribosomes - ANSWER>>>-protein synthesis
- site of action for aminoglycosides, erythromycin, tetracyclines and chloramphenicol function of nucleoid - ANSWER>>>Contains DNA function of mesosome - ANSWER>>>cell division and secretion Function of plasma membrane - ANSWER>>>site of oxidative and transport enzymes function of capsule - ANSWER>>>-protects against phagocytosis
- sticks to cell
Function of pilus or fimbria - ANSWER>>>(1) sticks to cell (2) sex pilus attaches 2 bacteria during conjugation function of flagellum - ANSWER>>>motility Function of spore - ANSWER>>>Provides resistance to dehydration, heat chemicals Function of plasmid - ANSWER>>>variety of genes for antibiotic resistance and toxins Function of granule - ANSWER>>>site of nutrients in cytoplasm Function of glycocalyx - ANSWER>>>adherence to surfaces What is the only bacteria without a regular cell wall? - ANSWER>>>Mycoplasma species Only ____ bacteria has an outer membrane containing endotoxin (lipopolysaccharide [LPS]) - ANSWER>>>gram-negative Gram-positive cells traits - ANSWER>>>-thicker, multilayer peptidoglycan
- teichoic acids
- NO LPS Gram-negative traits - ANSWER>>>-thinner; single layer
- LPS (endotoxin)
- NO teichoic acids Which bacteria will lipophilic drugs pass through easier? - ANSWER>>>Gram positive Which bacteria will HYDROphilic drugs pass through easier? - ANSWER>>>Gram negative What makes gram negative bacteria hydrophilic? - ANSWER>>>Porin proteins in channel What are the precursors for peptidoglycan? Where is it made? - ANSWER>>>NAM & NAG cytoplasm Where does bacteria make its cell wall? - ANSWER>>>Periplasmic space What carrier drops off NAM/NAG into periplasmic space? - ANSWER>>>C55 lipid carrier or bactoprenol What drug targets NAM/NAG? - ANSWER>>>Bacitracin First step in periplasmic space in building cell wall. What is the enzyme responsible? - ANSWER>>>transglycosylation aka polymerization
Plasmids occur in which bacteria? - ANSWER>>>both gram-positive and gram- negative bacteria Functions of plasmids - ANSWER>>>(1) Antibiotic resistance, which is mediated by a variety of enzymes. (2) Resistance to heavy metals, such as mercury, the active component of some antiseptics (e.g., merthiolate and mercurochrome), and silver, which is mediated by a reductase enzyme. (3) Resistance to ultraviolet light, which is mediated by DNA repair enzymes. (4) Pili (fimbriae), which mediate the adherence of bacteria to epithelial cells. (5) Exotoxins, including several enterotoxins. Transmissable vs. Nontransmissable plasmids - ANSWER>>>Transmissible
- Can be transferred cell to cell by conjugation
- Larger
- Few copies Nontransmissible
- Smaller
- NO tansfer gene
- Many copies Transposons - ANSWER>>>-DNA pieces that move readily from one site to another either within or between the DNAs of bacteria, plasmids, and bacteriophages
- code for antibiotic resistance Which genus form endospores? - ANSWER>>>Bacillus Clostridium Bacillus rods Gram positive SPores traits - ANSWER>>>- KIlled only above 121 °C
- live many years
- no metabolic activity
- ONLY sporicidal disinfectant works
- cause tetanus and gas gangrene Which part of spore causes resistance? - ANSWER>>>dipicolinic acid
a calcium ion chelator found only in spores What diseases can be caused by spores? - ANSWER>>>tetanus gas gangrene A bacteria without a capsule is ____. - ANSWER>>>nonpathogenic What features help bacteria attach to human cell? - ANSWER>>>-capsule
- pili Flagella may allow some bacteria species to cause _____. Flagella also allow laboratories to identify _____. - ANSWER>>>UTI specific antibodies The _____ bacterial component exhibits the most antigenic variation - ANSWER>>>Capsule Pili usually found on which bacteria? - ANSWER>>>gram negative Glycocalyx is aka as ______ - ANSWER>>>slime layer Glycocalyx adheres firmly to which structures? - ANSWER>>>skin heart valves prosthetic joints IV catheters teeth Bacteria have capsules composed of ______. - ANSWER>>>Polysaccharide Gram staining procedure - ANSWER>>>(1) The crystal violet dye stains all cells blue/purple. (2) Iodine solution forms crystal violet-iodine complex; all cells continue to appear blue. (3) Organic solvent, (acetone or ethanol) extracts blue dye complex from the gram-negative bacteria more than from gram-positive bacteria; gram-negative organisms appear colorless; gram-positive bacteria remain blue. (4) Red dye safranin stains gram-negative cells red/pink; the gram-positive bacteria remain blue. Medically important bacteria that CANNOT be seen in gram stain - ANSWER>>>-Mycobacteria
- Treponema pallidium
- mycoplasma
- Legionella pneumophila
- Chlamydiae
- Rickettsiae
- Gram positive c. Non-spore-forming rods - ANSWER>>>1) filamentous Corynebacterium Listeria
- filamentous Actinomyces Nocardia
- Gram negative a. Cocci - ANSWER>>>Neisseria What does neisseria cause? - ANSWER>>>gonorrhea, meningitis facultative anaerobes - ANSWER>>>can live with or without oxygen What disease is caused by mycoplasma? - ANSWER>>>Pneumonia Gram negative bacteria that is stained acid-fast - ANSWER>>>Mycobacterium List the major essential elements needed by bacteria and their uses - ANSWER>>>Carbon (energy and biosynthesis) N- amino acid/ nucleic acid biosynthesis P- nucleic acid biosynthesis S- mainly used for methionone/cysteine What specific bacteria species are spore formers? - ANSWER>>>-Clostridium tetani
- Clostridium perfringens
- Bacillus anthracis Understand the two main processes of bacterial metabolism (energy generation) - respiration and fermentation - ANSWER>>>Fermentation- ATP yielding process, using substrate-level phosphorylation;
internal electron acceptors are used; O2 is absent Respiration: An ATP yielding process, using electron transport phosphorylation; external compound is used as terminal electron acceptor; O2 is electron acceptor. Discuss the differences between the terms - strict aerobe, facultative, strict anaerobe and microaerophile based upon bacterial metabolism - ANSWER>>>Strict aerobe- ALWAYS respiration Pseudomonas aeruginosa Facultative: E. coli, Salmonella typhi (respiration or fermentation) Strict anaerobe: Clostridium tetani (ALWAYS fermentative) Microaerophilic: Helicobacter pylori (must have less O2 than atmospheric but always use respiration) Understand how bacterial endospores are formed and their importance - ANSWER>>> Describe the nature of bacterial growth/bacterial cell division - ANSWER>>>exponential growth: doubling each time Staphylococcus and streptococcus are sometimes also called _______. - ANSWER>>>gram-positive pyogenic cocci Staphylococcus coagulase-positive (clot blood) - ANSWER>>>S. aureus most pathogenic Staphylococcus coagulase-negative (doesn't clot) - ANSWER>>>S. epidermis Which of the following is NOT a virulence factor mentioned in class? A. Motility B. Adhesive structure C. Encapsulation D. Biochemical mechanisms for manipulating host immune defenses E. Resistance to antimicrobial drugs - ANSWER>>>E. Resistance to antimicrobial drugs
- presence of cell carbs A- partial hemolysis (cloudy) B- complete hemolysis (clear)
- Hemolytic
- Biochemical B-hemolytic streptococci - ANSWER>>>S. pyogenes and S. agalactiae α-hemolytic streptococci - ANSWER>>>S. pneumoniae S. anginosus Lancefield group - ANSWER>>>Streptococcus pyogenes (Group A) Streptococcus agalactiae (Group B) Describe the diseases caused by Streptococcus pyogenes, and their transmission, prevention and appropriate examples of treatment. - ANSWER>>>-strep throat
- cutaneous infections (impetigo, erysipelas, cellulitus)
- acute necrotizing fascitis
- STSS (infection surgical wound)
- Rheumatic fever Describe the diseases caused by S. agalactiae and their transmission, prevention and appropriate examples of treatment. - ANSWER>>>-most common disease in neonates UTI in women post and pre-pregnancy Tx: Penicillin/Vancomycin Why should strep throat be treated asap? - ANSWER>>>rheumatic fever Describe the diseases caused by S. pneumoniae, and their transmission, prevention and appropriate examples of treatment. - ANSWER>>> Describe the diseases caused by S. anginosus, and their transmission, prevention and appropriate examples of treatment. - ANSWER>>>Endodontic abscesses
_____ readily colonizes implanted devices. - ANSWER>>>S. epidermidis Which bacteria is most prevalent pathogen in endodontic abscesses - ANSWER>>>Streptococcus anginosus Which bacteria causes highest percentage of community acquired pneumonia? - ANSWER>>>Streptococcus pneumoniae Bacillus is a(n) _____ - ANSWER>>>Gram + Rod Aerobe OR facultative Clostridium is a(n) _____ - ANSWER>>>Gram + rod obligate anaerobe Describe the diseases, their transmission, prevention and appropriate examples of treatment associated with: a. Bacillus anthracis - ANSWER>>>Bacillus anthracis forms plasmids which codes for exotoxins Bacillus anthracis toxins - ANSWER>>>Edema toxin: Fluid accumulation in diseases Lethal toxin Causes TNF (tumor necrosis factor) Anthrax is mainly a disease of ____. - ANSWER>>>ruminants (cattle, sheep, goats) Anthrax is transmitted in 3 ways. - ANSWER>>>cutaneous pulmonary gastrointestinal Tx of anthrax - ANSWER>>>Ciprofloxacin tetracycline Penicillin G Treat cutaneous w/ 1, pulmonary with multiple Bacillus cereus causes _____ - ANSWER>>>eye infection especially after cataract surgery
Tx: metronidazole or Penicillin G What toxin used for wrinkles and blepharospasm? - ANSWER>>>Botox
- Botulism toxin Infant botulism caused by ____ - ANSWER>>>C. botulism growth in GIT Describe the diseases, their transmission, prevention and appropriate examples of treatment associated with: b. Clostridium difficile - ANSWER>>>Too much ampicillin/ clindamycin
- causes diarrhea/colitis Tx: Probiotics Vancomycin or fidaxomicin
