Introduction General Introduction General MicrobiologyMicrobiology

Prof. Dr. Asem Shehabi Prof. Dr. Asem Shehabi

Faculty of Medicine Faculty of Medicine

University of JordanUniversity of Jordan

The Microbial WorldThe Microbial World The microbial world is composed of The microbial world is composed of

microorganisms.. microorganisms.. Bacteria, Fungi (Yeast/ Moulds), Bacteria, Fungi (Yeast/ Moulds), Protozoa/ Protozoa/ ParasitesParasites and and virusesviruses.... Microbes.Microbes.

MicrobiologyMicrobiology is concerned with the study of these is concerned with the study of these microbes..microbes.. Most are beneficial.. FewMost are beneficial.. Few causecause harmful harmful effectseffects .. ..disease in human & animalsdisease in human & animals. .

MicroorganismsMicroorganisms are unicellular cell.. too small to be are unicellular cell.. too small to be seen with the naked eyeseen with the naked eye.. recognized by .. recognized by light light microscope.. Most microbes capable of grow & microscope.. Most microbes capable of grow & existence as single organism.. Widely distributed in existence as single organism.. Widely distributed in Human, Animal, Nature. Human, Animal, Nature.

MicrobiologyMicrobiology

VirusesViruses .. DNA or RNA..< 0.01um.. can be seen .. DNA or RNA..< 0.01um.. can be seen with electron microscope.. are non independent with electron microscope.. are non independent cellular entities.. grow only in living cells.. Can’t cellular entities.. grow only in living cells.. Can’t be considered true microorganisms.be considered true microorganisms.

MicrobiologyMicrobiology has many areas of specialization has many areas of specialization including including BacteriologyBacteriology,, MycologyMycology (fungi), (fungi), VirologyVirology, Medical microbiology and , Medical microbiology and Immunology, Food microbiology, Biotechnology, Immunology, Food microbiology, Biotechnology, Microbial genetics ..Industry.. Agriculture Microbial genetics ..Industry.. Agriculture Veterinary. Veterinary.

Classification of MicroorganismsClassification of Microorganisms

Two fundamentally different types of cells are Two fundamentally different types of cells are classified in the microbial world,classified in the microbial world, prokaryoticprokaryotic andand eukaryotic eukaryotic cellscells..

Eukaryotic cellsEukaryotic cells have a " have a "true" nucleustrue" nucleus.. .. Prokaryotic cellsProkaryotic cells have a have a naked nucleus/ naked nucleus/ Chromosome..Chromosome.. because their DNA is  not because their DNA is  not enclosed within a nuclear membrane.enclosed within a nuclear membrane.

The shape of Bacterial/Fungi/Parasites cells are The shape of Bacterial/Fungi/Parasites cells are of fundamental importance in the of fundamental importance in the classification classification and identification of these microbes. and identification of these microbes.

BacteriaBacteria BacteriaBacteria are unicellular microorganisms.. are unicellular microorganisms.. SizeSize (0.2umDiameter, 0.2-10um Length)(0.2umDiameter, 0.2-10um Length) having a having a

variety of shapes ..Growth patterns & metabolic variety of shapes ..Growth patterns & metabolic characteristics allowing their classification. characteristics allowing their classification.

Major bacteria cell shapes are arranged:Major bacteria cell shapes are arranged: Coccus/Coccus/coccicocci, , Bacillus/Bacillus/bacillibacilli or or RodsRods, , CoccobacilliCoccobacilli, , Spiral formsSpiral forms- spirochetes, Vibrios- spirochetes, Vibrios

Individual cells may be arranged in Individual cells may be arranged in pairspairs or or clusters clusters or or chainschains.. Their morphologies are .. Their morphologies are useful for the identification & classification of useful for the identification & classification of bacterial bacterial generagenera and and species species.. colored by .. colored by Gram-stain or other stains (Fig-1)Gram-stain or other stains (Fig-1)

Fig-1: Gram-Positive/NegativeFig-1: Gram-Positive/Negative

Figure -2 Figure -2 Prokaryote-Bacteria CellProkaryote-Bacteria Cell

Bacterial Cell structures-1Bacterial Cell structures-1

Main structures:Main structures: A rigid A rigid cell wallcell wall, , outer outer membranemembrane, A , A periplasmic spaceperiplasmic space,, a ,, a cytoplasmic cytoplasmic membranemembrane lacking sterols, lacking sterols, mesosomemesosome, , flagellumflagellum, fibmrae (pili), , fibmrae (pili), 70S ribosomes70S ribosomes, haploid , haploid one single one single chromosomechromosome, plasmids(, plasmids(>>1).1).

Flagella:Flagella: Organs of motility.. Attachment.. Organs of motility.. Attachment.. composed of flagellins (proteins) long composed of flagellins (proteins) long filament..20 um (Figure 2).filament..20 um (Figure 2).

Single polar flagellum Single polar flagellum (monotrichous)..(monotrichous).. Several Several polar flagella at one, each end of the cell or polar flagella at one, each end of the cell or covering the entire cell surface covering the entire cell surface (peritrichious)..(peritrichious).. antigenic determinants antigenic determinants (H-antigen)(H-antigen)

Bacterial Cell structures-2Bacterial Cell structures-2 Pili:Pili: Small Surface appendages (proteins).. Few Small Surface appendages (proteins).. Few

numbers Pili.. Sex function /Large Nos. fimbrae numbers Pili.. Sex function /Large Nos. fimbrae & 2 specific functions .. Attachment/Adhesins & 2 specific functions .. Attachment/Adhesins to host epithelial cells/colonization & antigenic to host epithelial cells/colonization & antigenic determinants. determinants.

CapsulesCapsules:: surface layer of cell wall.. a slime surface layer of cell wall.. a slime layer composed mostly of high molecular layer composed mostly of high molecular weight weight polysaccharidespolysaccharides.. provide resistance to .. provide resistance to phagocytosis.. avoid the killing effects of phagocytosis.. avoid the killing effects of lysosomal enzymes,lysosomal enzymes, and serve as antigenic and serve as antigenic determinants.. determinants.. (K-antigen)(K-antigen) Major Major virulence virulence factorfactor in certain bacteria in certain bacteria

Virulence factorVirulence factor.. Level of pathogenicity.. .. Level of pathogenicity.. Causing Causing InfectionInfection//diseasedisease

Cell wall Structures-1Cell wall Structures-1

Bacterial cell wall contains a special polymer Bacterial cell wall contains a special polymer called called peptidoglycanpeptidoglycan.. Its basic structure is a .. Its basic structure is a carbohydrate backbone of alternating units of carbohydrate backbone of alternating units of N-acetyl glucosamine and N-acetyl muramic N-acetyl glucosamine and N-acetyl muramic acid. acid.

These are cross-linked with These are cross-linked with oligopeptidesoligopeptides.. .. contain both D- and L-amino acids. contain both D- and L-amino acids.

Teichoic acid-Lipoteichoic acidsTeichoic acid-Lipoteichoic acids: Both are : Both are found only in Gram-positive bacteria.found only in Gram-positive bacteria.

LipopolysaccharidesLipopolysaccharides:: Lipopolysaccharides Lipopolysaccharides (LPS)(LPS) found only in Gram-negative bacteria. found only in Gram-negative bacteria.

Cell wall Structures-2Cell wall Structures-2

o These structures are composed of These structures are composed of lipid Alipid A, , which binds the LPS to the outer membrane.. which binds the LPS to the outer membrane.. the the endotoxicendotoxic portion of the molecule.. portion of the molecule.. Causing Toxic Shock.. High Fever, Sepsis Causing Toxic Shock.. High Fever, Sepsis

o The polysaccharide moiety appears on the The polysaccharide moiety appears on the cell surface, serving as an antigenic cell surface, serving as an antigenic determinant (determinant (O antigenO antigen).. in Infection.).. in Infection.

o Cell wall is the basis for classification of Cell wall is the basis for classification of bacteria in the Gram stain.. Gram-positive & bacteria in the Gram stain.. Gram-positive & Gram-negative ( Figure 3).Gram-negative ( Figure 3).

Gram-StainGram-StainA- A- Gram-positiveGram-positive bacteria have a thick bacteria have a thick

layer of peptidoglycan, Many sheets.. layer of peptidoglycan, Many sheets.. external to the cytoplasmic membrane.. external to the cytoplasmic membrane.. Lipoteichoic acids.. stained Lipoteichoic acids.. stained BlueBlue.. .. Staphyloccocus, StreptocoociStaphyloccocus, Streptocooci, Bacillus , Bacillus

B- B- Gram-negativeGram-negative bacteria contain bacteria contain lipopolysaccharide (LPS) attached to the lipopolysaccharide (LPS) attached to the outer membrane... This is the source of outer membrane... This is the source of the the O-antigenO-antigen and endotoxin reaction.. and endotoxin reaction.. Stained Purpel/Red.. Stained Purpel/Red.. Enteric bacteria Enteric bacteria group.. group.. Esch. coli, Salmonella, BrucellaEsch. coli, Salmonella, Brucella

Spore-Forming BacteriaSpore-Forming Bacteria

o ENDOSPORE FORMATIONENDOSPORE FORMATION: : The process of The process of sporulation begins when vegetative (actively sporulation begins when vegetative (actively growing) cells exhaust their source of nutrients .. growing) cells exhaust their source of nutrients .. begin of forming begin of forming endosporesendospores. (Figure 4). . (Figure 4).

o Spore forming Bacteria are very resistant to Spore forming Bacteria are very resistant to lysozyme, heat, radiation, dryinglysozyme, heat, radiation, drying and can remain and can remain dormant for hundreds of years in nature..dormant for hundreds of years in nature.. Once Once conditions are again favorable for growth, the spores conditions are again favorable for growth, the spores can can germinategerminate and return to the and return to the vegetative statevegetative state..

o Aerobic Aerobic BacillusBacillus group and group and Anaerobic Anaerobic ClostridiumClostridium.... Endospore formation.. Both are widely distributed in Endospore formation.. Both are widely distributed in nature ..intestinal of human and animals.nature ..intestinal of human and animals.

Figure-4 Bacterial SporeFigure-4 Bacterial Spore

Growth & Nutrition-1Growth & Nutrition-1 Requirements for bacterial growth:Requirements for bacterial growth:

oxygen, water, pH, temperature, source of oxygen, water, pH, temperature, source of carbon, nitrogen ( organic compounds), carbon, nitrogen ( organic compounds), inorganic salts.. Na, K, S, P, Ca, Mg, Cl, Fe, inorganic salts.. Na, K, S, P, Ca, Mg, Cl, Fe, vitamins, etc.vitamins, etc.

ObligateObligate aerobic aerobic bacteria bacteria ....M. tuberculosisM. tuberculosis.. .. grow using respiration.. oxidation.. recipientgrow using respiration.. oxidation.. recipient OxygenOxygen.. .. Aerobic bacteriaAerobic bacteria encounter the encounter the oxygen damage during their growth by oxygen damage during their growth by producing oxidizing enzymes: producing oxidizing enzymes:

Peroxidase:Peroxidase: oxidize H oxidize H22OO22 into 2H2O+NAD. into 2H2O+NAD. Superoxidase dismutaseSuperoxidase dismutase reduce O reduce O22- into H- into H22OO22

+O2. ..+O2. .. Catalase:Catalase: reduce H reduce H22OO2 2 into 2Hinto 2H22O+OO+O2.2.

Growth & Nutrition-2Growth & Nutrition-2 Bacteria classified by the source of their energy Bacteria classified by the source of their energy

oxidation-reduction processoxidation-reduction process into into two groups: two groups: HeterotrophsHeterotrophs:: derive energy from breaking derive energy from breaking

down complex organic compounds.. protein, down complex organic compounds.. protein, sugar, fats.. human tissues (commensals-sugar, fats.. human tissues (commensals-pathogens)pathogens)

AutotrophsAutotrophs:: fix carbon dioxide to make their fix carbon dioxide to make their own food source.. using light energy own food source.. using light energy photoautotrophicphotoautotrophic, or oxidation of nitrogen, , or oxidation of nitrogen, sulfur, other elements sulfur, other elements chemoautotrophicchemoautotrophic.. .. sulfur & nitrogen fixing bacteria.. Environment.sulfur & nitrogen fixing bacteria.. Environment.

Saprophytic bacteriaSaprophytic bacteria/ Nonpathogenic.. take / Nonpathogenic.. take energy by energy by fermentationfermentation//respirationrespiration. found in . found in nature.. in decaying material.. soil, nature.. in decaying material.. soil, water..vegetations..circulation of minerals. water..vegetations..circulation of minerals.

Growth & Nutrition-3Growth & Nutrition-3

Certain PathogensCertain Pathogens grow with reduced level of grow with reduced level of oxygenoxygen.. .. MicroaerophilicMicroaerophilic bacteria bacteria....NeisseriaNeisseria

facultative anaerobes..facultative anaerobes.. prefer growing in the prefer growing in the presence of oxygen, but can continue to grow presence of oxygen, but can continue to grow without it.. Most human pathogens & normal without it.. Most human pathogens & normal flora.. Staphylococci, streptococci, E.coliflora.. Staphylococci, streptococci, E.coli

Obligate AnaerobicObligate Anaerobic bacteria grow by absence bacteria grow by absence of oxygen.. use recipient inorganic molecule.. of oxygen.. use recipient inorganic molecule.. Fermentation.. Mostly found in intestinal tract Fermentation.. Mostly found in intestinal tract (95-99%), Mouth &Vagina(90%)(95-99%), Mouth &Vagina(90%)

Examples: Gram-ve Bacteriodes fragil, G+ve Examples: Gram-ve Bacteriodes fragil, G+ve Clostridia, Gram+ve CocciClostridia, Gram+ve Cocci

4/4/ Culture Media:Culture Media: Nutrients (carbohydrates & Nutrients (carbohydrates &

proteins, blood) Source.. Water..Broth medium, proteins, blood) Source.. Water..Broth medium, Solid medium/ Blood agar, Petri dishes/Plate.. Solid medium/ Blood agar, Petri dishes/Plate.. Growth/Culture (Fig 5) Growth/Culture (Fig 5)

NeutrophilicNeutrophilic bacteria.. Grow best pH (7-7.2) bacteria.. Grow best pH (7-7.2) Most human-animal Most human-animal commensales & pathogenscommensales & pathogens

AcidophilicAcidophilic Bacteria Bacteria < 5 pH.. Lactobacilli < 5 pH.. Lactobacilli MesophilesMesophiles Bacteria (20-40 C).. Most human Bacteria (20-40 C).. Most human

pathogens, pathogens, PsychrophilesPsychrophiles bacteria(<10C) bacteria(<10C) ThermophilesThermophiles bacteria ( > 60oC)..Common in bacteria ( > 60oC)..Common in WaterWater

Counting bacteria growthCounting bacteria growth:: Plate counts, Plate counts, Turbidity, Dry weight.Turbidity, Dry weight.

Bacterial growthBacterial growth Bacterial growthBacterial growth is the is the divisiondivision of one of one

bacteriumbacterium into two idential daughter cells.. into two idential daughter cells.. binary fissionbinary fission. .

Baterial GrowthBaterial Growth Curve: Curve: 4 phases Lag, Log, 4 phases Lag, Log, Stationary, death/ decline. Stationary, death/ decline.

Measurement of bacterial growth followed by: Measurement of bacterial growth followed by: A) Growth/enumeration of cells by direct cell A) Growth/enumeration of cells by direct cell

counting in nutrient broth.. microscopic or counting in nutrient broth.. microscopic or counting viable cells/ colony forming unit.. Plate counting viable cells/ colony forming unit.. Plate countscounts/ / Electronic counting..Nutrient agar Electronic counting..Nutrient agar

B) Indirect counting of growth in fluid medium.. B) Indirect counting of growth in fluid medium.. most probable number by measuring turbidity, most probable number by measuring turbidity, wet or dry weight.. Gram/ml.. Important in wet or dry weight.. Gram/ml.. Important in research of antibiotics, treatment of infection.. research of antibiotics, treatment of infection..

Bacterial Growth –MacConkey agarBacterial Growth –MacConkey agar& Tube Broth& Tube Broth

Bacteria Binary FissionBacteria Binary Fission

Bacteria Growth CurveBacteria Growth Curve