Microbiology - General Bacteriology 2 PDF

Level (1) - Semester (1) MICROBIOLOGY D R Z I A D M A LECTURE (3) H A N GENERAL BACTERIOLOGY (2) A  - ① Carbon ⑤ Oxygen ① Temperature ② Nitrogen ⑥ Moisture ② PH...

Level (1) - Semester (1) MICROBIOLOGY D R Z I A D M A LECTURE (3) H A N GENERAL BACTERIOLOGY (2) A  - ① Carbon ⑤ Oxygen ① Temperature ② Nitrogen ⑥ Moisture ② PH ③ Sulfur ⑦ Trace elements ③ Osmotic pressure ④ Phosphorus ⑧ Organic growth factors 10 - 42°C for most of pathogenic bacteria 37°C for most of pathogenic bacteria (mesophiles). Grow at temperature less than 15°C. Grow at temperature more than 45°C.  - Most of the pathogenic bacteria grow at optimum pH of 7.5. Vibrio cholera. Lactobacillus.  Addition of salts or sugars to a solution increases its osmotic pressure,  Can be used to preserve foods.  High salt or sugar concentrations:  Get water out of bacteria & prevent their growth. Bacteria adapted to high salt Bacteria do not require high salt concentrations that they need for growth concentrations but are able to grow at salt (obligate halophiles). concentrations up to 2%.  -  The structural backbone of bacteria needed for all the organic compounds synthesis.  Requires nitrogen & some sulfur.  Require nitrogen & some phosphorus.  Bacterial body is made of good amount of water so, a high content of water is essential for bacterial cultivation.  Needed in very minute amounts; iron, copper & zinc  Bacteria produce:  Iron-binding compounds;  Siderophores to capture iron by chelating it.  Most vitamins function as coenzymes. Can grow well Grow best in Grow only in in presence or  Normal CO2 (0.3%) Grow in presence of presence of absence of O2, of ordinary absence of minimal O2 (M. most of atmosphere is O2. amount of tuberculosis) pathogenic usually sufficient oxygen. bacteria.  Some organisms require much higher conc. (5-10%) (Capnophilic). - Elongation of the bacterium.  Division of nuclear bodies.  Constriction from cell wall inwards.  Then the bacterium divides into two daughter cells.  - ① If a bacterium is cultivated in liquid medium. ② Number of viable cells per milliliter is determined periodically & plotted. ③ Typical growth curve of four phases is obtained.  No multiplication (growth rate is zero). ①  Bacteria increase in size & prepare for division (enzymatic synthesis).  Division occurs at a maximum rate. ②  Bacteria could be inhibited by antibiotics.  Rate of division equals rate of death, number of living organisms remains stationary.  Decrease rate of growth due to: ③  Deficiency of nutrients.  O2 decrease.  Accumulation of toxic materials.  Rate of death more than rate of growth.  Increase of death is due to accumulation of toxic ④ metabolites.  Antibiotic should be continued to completely eradicate bacteria to avoid development of antibiotic resistance.  -  Breakdown of complex molecules into simpler one:  Synthesis of complex molecules from  With production of energy (ATP) simpler one: needed for all cellular functions  With storage of energy. (anabolism). Catabolism + Anabolism = Metabolism. Catabolism & Anabolism occur simultaneously in cells. - A. Spreading Factors. B. Enzymes Causing Hemolysis &/or Leucolysis. C. Coagulase. D. IgA1 Proteases.  Play a role in bacterial respiration.  Remain bound to body of organism.  Not diffuse into surrounding medium. Serratia marcescens. Staphylococcus aureus.  Diffuse into surrounding medium.  Pseudomonas aeruginosa produces: Pyocyanin. Fluorescens.  - Diffusible Not (cell bound) ° Labile (denatured) Stable Strong Weak High Low (1 μg is fatal) (hundreds of μgs) Protein Lipopolysaccharide Some Gram -ve & +ve Gram -ve Toxoid (used in vaccination) Not affected ① Virulence factors: are any factors that enable a  The ability of an organism to: pathogen to produce disease in a host. ① Infect the host & ② Virulent microorganism: cause disease when ② Cause a disease. introduced into host in small numbers. -  Once microorganism enter the host, they must adhere to cell surface by specific surface structures; adhesins; Pili & Capsule.  Ability to enter host cells & spread in the body.  Helped by bacterial invasions: enzymes that damage host cells & facilitate spread of the pathogen; Coagulase, Phospholipases, Hemolysins.  The ability to produce toxins.  2 types of toxins: ① Exotoxins ② Endotoxins  Some pathogens are able to resist host defense against them.  Antiphagocytic Factors: Polysaccharide capsules.  Some bacteria (T.B) live & grow inside phagocytes.  IgA Proteases; split IgA, mucosal protection.  - Does Bacteria Eat?? Questions ① Bacteria which can grow in the presence or absence of oxygen are called: a. Facultative anaerobes. b. Microaerophilic. c. Obligatory aerobes. d. Obligatory anaerobes. ② Clostridium is: a. Facultative anaerobe. b. Microaerophilic. c. Obligatory aerobe. d. Obligatory anaerobe. ③ List types of bacteria according to Oxygen requirements. ……………………………………………………………………………..………….. ……………………………………………………………………………..………….. ……………………………………………………………………………..…………..