Bacteria classification and nutrition

This is presentation about classification and nutrition of bacteria. Bacteria are classified depending on various parameters viz. cell wall, temperature, air, salt concentration, Pressure, presence of flagella, pH etc.

1. BACTERIA: CLASSIFICATION AND NUTRITION Unit I Pharmaceutical Microbiology B. Pharm III Sem. Mr.Krishnakant B. Bhelkar Asst. Professor, Gurunanak College of Pharmacy, Nagpur

2. Bacteria: Classification Bacteria are classified on various basis those are: Classification on the basis of Bergey's 4 Divisions ( Gram Stainning and Bacterial Cell Wall) Shape Mode of Nutrition Temperature Requirement Oxygen Requirement pH of Growth Osmotic Pressure Requirement Number of Flagella Spore Formation 2 Gurunanak College of Pharmacy, Nagpur

3. Bacteria: Classification Bergey's 4 Divisions of Bacteria Division: Gracilicutes Gracilicutes ( gracilis = slender, and  cutis =skin) have a cell wall that is consistent with being  gram negative  even though they do not necessarily stain gram negative. Examples of gracilicutes include  E. coli, Klebsiella pneumoniae , Neisseria , Rickettsia , Trepanoma pallidum . Division: Firmicutes Firmicutes ( firmus = strong, and  cutis= skin) have mostly a  gram positive  cell wall structure.  Examples include  Bacillus, Staphylococcus, Streptococcus, Clostridium , Mycobacterium , Corynebacterium diphteriae . Division: Tenericutes Tenericutes (soft skin) have no cell wall. A notable example is mycoplasma. Division: Mendosicutes Mendosicutes (faulty skin) have no murein in cell walls, and are also known as archaea. These can stain both gram positive or negative, since archaea have a lot of variety. Defective cell wall with unusual cell wall composition. 3 Gurunanak College of Pharmacy, Nagpur

4. Difference Between Gram Positive and Gram Negative Bacteria Characteristic Gram Positive Gram Negative Gram Staining Retain crystal violet Appear violet colored Decolorized and stained by counter stain Appear red coloured Layers One Two Peptidoglycan Layer Thick (Multilayered) Thin (Single layered) Teichoic acid Present Absent Perplasmic space Absent Present Lipopolysaccharide Content Almost absent High Lipid and lipoprotein Low High Flagellar Rings Two Four Toxins produced Exotoxin Endotoxin 4 Gurunanak College of Pharmacy, Nagpur

5. Characteristic Gram Positive Gram Negative Resistance to physical disruption High Low Cell wall disruption by lysozyme High Low Resistance to drying High Low Inhibition by basic dyes High Low Susceptibility to anionic detergents High Low Resistance to antibiotics Low High Difference Between Gram Positive and Gram Negative Bacteria ( Contd …..) 5 Gurunanak College of Pharmacy, Nagpur

6. Shapes of Bacteria There are three basic shapes of bacteria Spherical shaped: cocci (Singular: Coccus ) Rod or cylindrical shaped: bacilli (Singular: Bacillus), and Spiral shaped: Spirilla  (Singular: spirillum ) Other Shapes: 6 Gurunanak College of Pharmacy, Nagpur

7. Spatial Arrangements and Shapes of bacterial Cells 7 Gurunanak College of Pharmacy, Nagpur

8. Bacteria: Classification 8 Gurunanak College of Pharmacy, Nagpur

9. On the basis of  energy source  organisms are designated as: Phototrophs : The organisms which can utilize light as an energy source are known as phototrophs . These bacteria gain energy from light. Chemotrophs : These bacteria gain energy from chemical compounds. They cannot carry out photosynthesis. On the basis of  electron source  organisms are designated as: Lithotrophs :   Some organisms can use reduced organic compounds as electron donors and are termed as Lithotrophs . They can be Chemolithotrophs and Photolithotrophs Organotrophs :  Some organisms can use organic compounds as electron donors and are termed as  organotrophs . Some can be Chemoorganotrophs and Photoorganotrophs . Bacteria: Classification 9 Gurunanak College of Pharmacy, Nagpur

10. Autotrophs and Heterotrophs These bacteria synthesize all their food from inorganic substances (H2O, C02, H2S salts). The autotrophic bacteria are of two types : ( i )  Photoautotrophs and (ii) Chemoautotrophs ( i )  Photoautotrophs These bacteria capture the energy of sunlight and transform it into the chemical energy. In this process, CO2 is reduced to carbohydrates. The hydrogen donor is water and the process produce free oxygen. Photoautotroph has Chlorophyll pigment in the cell and its main function is to capture sunlight e.g.,  Cyanobacteria . Some photoautotrophic bacteria are anaerobes and have bacteriochlorophyll and  bacteriovirdin  pigments respectively. 10 Gurunanak College of Pharmacy, Nagpur

11. Autotrophs and Heterotrophs ( Contd …..) Purple Sulphur Bacteria: These bacteria have the pigment bacteriochlorophyll located on the intracytoplasmic membrane i.e., thylakoids . These bacteria obtain energy from sulfur compounds e.g.,  Chromatiiun . Theopedia rosea , Thiospirilium . Green Sulphur Bacteria: These bacteria use hydrogen sulfide (H2S) as hydrogen donor. The reaction takes place in the presence of light and pigment termed as  bacteriovirdin  or bacteriopheophytin or  chlorobium  chlorophyll e.g.,  Chlorobium   limicola , Chlorobacterium  etc. These bacteria take hydrogen from inorganic sources like  sulphides  and thiosulphates . Therefore, these bacteria are also known as photolithographs. 11 Gurunanak College of Pharmacy, Nagpur

12. Autotrophs and Heterotrophs ( Contd …..) (ii) Chemoautotrophs These bacteria do not require light (lack the light phase but have the dark phase of photosynthesis) and pigment for their nutrition. These bacteria oxidize certain inorganic substances with the help of atmospheric oxygen. This reaction releases the energy (exothermic) which is used to drive the synthetic processes of the cell. 12 Gurunanak College of Pharmacy, Nagpur

13. Bacterial Classification as per Gaseous Requirement Depending on the gaseous requirement, Bacteria are classified in four types as follows….. Aerobic Microorganisms Anaerobic Microorganisms Facultative Microorganisms Microaerophilic Microorganisms 13 Gurunanak College of Pharmacy, Nagpur

14. Require oxygen to live. Example:  Pseudomonas , common nosocomial pathogen Aerobic Bacteria 14 Gurunanak College of Pharmacy, Nagpur

15. Anaerobic Bacteria Cannot use oxygen and are harmed by the presence of toxic forms of oxygen. Examples:  Clostridium  bacteria that cause tetanus and botulism. 15 Gurunanak College of Pharmacy, Nagpur

16. Facultative Anaerobic Bacteria Can use oxygen, but can grow in its absence. They have complex set of enzymes. Examples:  E. coli, Staphylococcus , yeasts, and many intestinal bacteria. 16 Gurunanak College of Pharmacy, Nagpur

17. Microaerophilic Bacteria Require oxygen, but at low concentrations. Sensitive to toxic forms of oxygen. Example:  Campylobacter . 17 Gurunanak College of Pharmacy, Nagpur

18. Bacterial Classification as per Temperature Requirement Depending on the temperature requirement for optimum growth, Bacteria are classified in three types as follows….. Thermophiles Mesophiles Psycchrophiles 18 Gurunanak College of Pharmacy, Nagpur

19. Bacterial Classification as per Temperature Requirement Thermophiles : Those bacteria that can best grow above 45˚C. Thermophiles capable of growing in mesophilic range are called facultative thermophiles . True thermophiles are called as Stenothermophiles , they are obligate thermophiles , Thermophils contains saturated fattyacids in their cell membrane so their cell membrane does not become too fluid even at higher temperature. Examples:  Streptococcus thermophiles , Bacillus stearothermophilus , Thermus aquaticus . Hypethermophiles : Those bacteria that have optimum temperature of growth above 80C. Mostly Archeobacteria are hyperthermophiles . Monolayer cell membrane of Archeobacteria is more resistant to heat and they adopt to grow in higher remperature . Examples:  Thermodesulfobacterium , Aquifex , Pyrolobus fumari , Thermotoga . 19 Gurunanak College of Pharmacy, Nagpur

20. . Mesophiles : Those bacteria that can grow best between (25-40) o  C but optimum temperature for growth is 37˚̊C Most of the human pathogens are mesophilic in nature. Examples:  E. coli, Salmonella, Klebsiella , Staphylococci. Bacterial Classification as per Temperature Requirement 20 Gurunanak College of Pharmacy, Nagpur

21. Psychrophiles : Bacteria that can grow at 0°C or below but the optimum temperature of growth is 15 °C or below and maximum temperature is 20°C are called psychrophiles Psychrophiles have polyunsaturated fatty acids in their cell membrane which gives fluid nature to the cell membrane even at lower temperature. Examples:  Vibrio psychroerythrus , vibrio marinus , Polaromonas vaculata , Psychroflexus . Psychrotrops (facultative psychrophiles ): Those bacteria that can grow even at 0°C but optimum temperature for growth is (20-30)°C Bacterial Classification as per Temperature Requirement 21 Gurunanak College of Pharmacy, Nagpur

22. Acidophiles : These bacteria grow best at an acidic pH. The cytoplasm of these bacteria are acidic in nature. Some acidopiles are thermophilic in nature, such bacteria are called Thermoacidophiles . Examples:  Thiobacillus thioxidans ,  Thiobacillus , ferroxidans , Thermoplasma , Sulfolobus Alkaliphiles : These bacteria grow best at an alkaline pH. Example:  Vibrio cholerae  optimum ph of growth is 8.2. Neutrophiles : These bacteria grow best at neutral pH (6.5-7.5). Most of the bacteria grow at neutral pH. Example:  E. coli Bacterial Classification as per pH Requirement 22 Gurunanak College of Pharmacy, Nagpur

23. Halophiles : Require moderate to large salt concentrations. Cell membrane of halophilic bacteria is made up of glycoprotein with high content of negatively charged glutamic acid and aspartic acids. So high concentration of Na+ ion concentration is required to shield the – ve charge. Ocean water contains 3.5% salt. Most such bacteria are present in the oceans. Archeobacteria , Halobacterium , Halococcus . Bacterial Classification as per Requirement of osmotic pressure 23 Gurunanak College of Pharmacy, Nagpur

24. On the basis of flagella the bacteria can be classified as: Atrichos : –   These bacteria has no flagella. Example:  Corynebacterium diptherae . Monotrichous :  – One flagellum is attached to one end of the bacteria cell. Example: –  Vibro cholerae . Lophotrichous : –   Bunch of flagella is attached to one end of the bacteria cell. Example:  Pseudomonas . Amphitrichous :  – Bunch of flagella arising from both end of the bacteria cell. Example:  Rhodospirillum rubrum . Peritrichous  :  – The flagella are evenly distributed surrounding the entire bacterial cell. Example:  Bacillus Bacterial Classification as per Presence and Number of Flagella 24 Gurunanak College of Pharmacy, Nagpur

25. Bacterial Classification as per Presence and Number of Flagella 25 Gurunanak College of Pharmacy, Nagpur

26. Spore forming bacteria: Those bacteria that produce spore during unfavorable condition. These are further divided into two groups: i ) Endospore forming bacteria:  Spore is produced within the bacterial cell. Examples.  Bacillus, Clostridium, Sporosarcina  etc ii) Exospore forming bacteria:   Spore is produced outside the cell. Example .  Methylosinus Non sporing bacteria: Those bacteria which do not produce spores. Eg .  E. coli, Salmonella. Bacterial Classification as per Formation of spores 26 Gurunanak College of Pharmacy, Nagpur

27. Bacterial Nutrition Type of Nutrient Function Examples Carbon Source Provide energy through oxidation and provides various structural components of bacterial cell Carbon di oxide and any other carbon containing organic or inorganic substances Nitrogen Source Necessary for synthesis of amino acids, nucleic acids and coenzymes Atmospheric nitrogen and other inorganic nitrogen compounds like NO or NH 4 + and organic compounds such as aspargine or glutamine Inorganic Ions Works as cofactors for enzymes in various biochemical reactions, in storage of energy and electron transport system Mg 2 + , Mn 2 + , Fe 2 + , PO 4 2- , Na + , K + and Mo Vitmines and Other Essential metabolites Provide complex organic compounds which an organism is unable to synthesize Vitamines , amino acids, purines , pyrimidines , coenzymes and heme 27 Gurunanak College of Pharmacy, Nagpur

28. Some Terminologies Media or Medium (Bacteriological) Bacterial Culture Fastidious organism Bacterial Nutrition 28 Gurunanak College of Pharmacy, Nagpur

29. Liquid Media: Bacteriological media in liquid physical state is called as broth medium. It is meant for growth of pure batch cultures. In broth medium bacterial cells are present in suspended form. Semisolid Media Semisolid media are used widely for the isolation of pure cultures, for estimating viable bacterial populations, and a variety of other purposes. e.g. Nutrient Agar, EMB Agar The usual gelling agent for solid or  semisolid medium  is  Agar , a hydrocolloid derived from red algae. Agar is used because of its unique physical properties (it melts at 100 o C and remains liquid until cooled to 40 o C, the temperature at which it gels) and because it cannot be metabolized by most bacteria. Hence as a medium component it is relatively inert Bacterial Nutrition (Types of Bacterial Media) 29 Gurunanak College of Pharmacy, Nagpur

30. Bacterial Nutrition (Types of Bacterial Media) Natural or Complex Media Synthetic Media (Chemically Defined Media) Chemical composition may not be so clearly known The exact chemical composition is known Usually contains materials of biological origin such as blood or milk, peptone yeast extract and beef extract. Synthetic media usually contains peptone water medium complex media provides a full range of growth factors Synthetic media provides only limited growth factors. Used for the cultivation of heterotrophic microorganisms Used for the cultivation of autotrophs 30 Gurunanak College of Pharmacy, Nagpur

31. 1. Basal Media. Basal media are those that may be used for growth (culture) of bacteria that do not need enrichment of the media. Examples: Nutrient broth, nutrient agar and peptone water. 2. Enriched Media. Enriched media contain the nutrients required to support the growth of a wide variety of organisms, including some fastidious ones. The media are enriched usually by adding blood, serum or egg. Examples: Blood agar 3. Enrichment Media Enrichment media promotes the growth of a particular organism by providing it with the essential nutrients and rarely contains certain inhibitory substance to prevent the growth of normal competitors. Example: Selenite F broth favors the growth of Salmonella Bacterial Nutrition (Types of Bacterial Media) 31 Gurunanak College of Pharmacy, Nagpur

32. 4. Selective Media . These media favour the growth of a particular bacterium by inhibiting the growth of undesired bacteria and allowing growth of desirable bacteria. Examples: MacConkey agar, Lowenstein-Jensen media, tellurite media ( Tellurite inhibits the growth of most of the throat organisms except diphtheria bacilli). (Antibiotic may be added to a medium for inhibition.) 5. Differential (Indicator) Media. An indicator is included in the medium. A particular organism causes change in the indicator, e.g. blood, neutral red, tellurite . Examples: Blood agar and MacConkey agar are indicator media. Bacterial Nutrition (Types of Bacterial Media) 32 Gurunanak College of Pharmacy, Nagpur

33. 6. Transport Media. (Media For Transportation) These media are used when specie-men cannot be cultured soon after collection. Examples: Cary-Blair medium, Amies medium, Stuart medium. 7. STORAGE MEDIA (Media for Preservation). Media used for storing the bacteria for a long period of time. Examples: Egg saline medium, chalk cooked meat broth 8. Assey Media These media are used for the assay of vitamins, amino acids, and antibiotics. E.g. antibiotic assay media are used for determining antibiotic potency by the microbiological assay technique. Other types of medium include; Bacterial Nutrition (Types of Bacterial Media) 33 Gurunanak College of Pharmacy, Nagpur

34. 9. Media for enumeration of bacteria Specific kinds of media are used for determining the bacterial content of such materials as milk and water. Their composition must adhere to prescribed specifications. e.g., Nutrient agar 10. Media for characterization of bacteria A wide variety of media are conventionally used to determine the types of growth produced by bacteria, as well as to determine their ability to produce certain chemical changes. 11. Maintenance media Satisfactory maintenance of the viability and physiological characteristics of a culture over time may require a medium different from that which is optimum for growth. Prolific, rapid growth may also be associated with rapid death of the cells at the end of the growth phase. For example, glucose in a medium frequently enhances growth, but acid harmful to the cells is likely to be produced. Therefore, omission of the glucose is preferable in a maintenance medium. Bacterial Nutrition (Types of Bacterial Media) 34 Gurunanak College of Pharmacy, Nagpur

35. Thank You….. Gurunanak College of Pharmacy, Nagpur 35