classification of bacteria classification of bacteria dr.thamina sayyed dr.thamina sayyed registrar...
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Classification of bacteriaClassification of bacteria
DR.THAMINA SAYYEDDR.THAMINA SAYYED
REGISTRARREGISTRAR
MICROBIOLOGYMICROBIOLOGY
KKUHKKUH
Classification SystemClassification System 3 Domains 1978 Carl Woese3 Domains 1978 Carl Woese
1. Bacteria 1. Bacteria • Unicellular prokaryotes with cell wall containing Unicellular prokaryotes with cell wall containing
peptidoglycanpeptidoglycan 2. Archaea2. Archaea
• Unicellular prokaryotes with no peptodoglycan Unicellular prokaryotes with no peptodoglycan in cell wallin cell wall
3.3. EukaryaEukarya• ProtistaProtista• FungiFungi• PlantaePlantae• AnimaliaAnimalia
Taxonomic Classification CategoriesTaxonomic Classification Categories
arranged in hierarchical orderarranged in hierarchical order species is basic unitspecies is basic unit
DomainDomainKingdomKingdom
Phylum or DivisionPhylum or DivisionClassClassOrderOrderFamilyFamilyGenusGenus
SpeciesSpecies
Prokaryote ClassificationProkaryote Classification
Technologies used to characterizeTechnologies used to characterize
and ID prokaryotesand ID prokaryotes microscopic examinationmicroscopic examination culture characteristicsculture characteristics biochemical testingbiochemical testing nucleic acid analysisnucleic acid analysis combination of the above is most accuratecombination of the above is most accurate
Phenotypic Characteristics for Identifying Phenotypic Characteristics for Identifying ProkaryotesProkaryotes
often does not require sophisticated often does not require sophisticated equipmentequipment
can easily be done anywherecan easily be done anywhere
Microscopic Phenotypic ExamMicroscopic Phenotypic Exam size and shape and arrangementsize and shape and arrangement
enough information for diagnosis of certain infectionsenough information for diagnosis of certain infections
Gram stainGram stain distinguishes between distinguishes between
Gram + and Gram – Gram + and Gram – bacteriabacteria
narrows the possibilities narrows the possibilities quicklyquickly
Microscopic Phenotypic ExamMicroscopic Phenotypic Exam
special stainspecial stain allows for the distinction of allows for the distinction of
microorganisms with unique microorganisms with unique characteristicscharacteristics• capsulecapsule• acid fast staining detects acid fast staining detects
the waxy presence of the waxy presence of Mycobacterium Mycobacterium tuberculosistuberculosis
Capsule staining
Acid fast staining of M. tuberculosis
CELL WALLCELL WALL
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Gram positive cell wallGram positive cell wall Consists of Consists of
a thick, homogenous a thick, homogenous sheath of peptidoglycan sheath of peptidoglycan 20-80 nm 20-80 nm thickthick
tightly bound acidic tightly bound acidic polysaccharides, polysaccharides, including including teichoic acid teichoic acid and lipoteichoic acidand lipoteichoic acid
cell membranecell membrane
Retain crystal violet and Retain crystal violet and stain purplestain purple
Gram negative cell wallGram negative cell wall Consists ofConsists of
an outer membrane an outer membrane containing containing lipopolysaccharide (LPS)lipopolysaccharide (LPS)
thin thin shell of shell of peptidoglycanpeptidoglycan
periplasmic spaceperiplasmic space inner membraneinner membrane
Lose crystal violet and Lose crystal violet and stain pink from safranin stain pink from safranin counterstaincounterstain
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Crystal violet
Gram's iodine
Decolorise with acetone
Counterstain withe.g. methyl red
Gram-positives appear purple
Gram-negatives appear pink
The Gram Stain
Metabolic Phenotypic ExamMetabolic Phenotypic Exam cultural approachescultural approaches
required for positive diagnosis of infectionrequired for positive diagnosis of infection isolation and ID of pathogenisolation and ID of pathogen accuracy, reliability, and speedaccuracy, reliability, and speed
methods used includemethods used include culture characteristicsculture characteristics biochemical reactions processbiochemical reactions process
Serological Testing Serological Testing Phenotypic ExamPhenotypic Exam
serological testing serological testing uses ELISA testinguses ELISA testing fast and easy to usefast and easy to use
Classification of medically significant bacteriaClassification of medically significant bacteria
I.Thick rigid walled cellsI.Thick rigid walled cells
A. Free living extracellularA. Free living extracellular
1.Gram positive1.Gram positive
a.Cocci a.Cocci Staphylococcus - abcessStaphylococcus - abcess
Streptococcus - puemonia,Streptococcus - puemonia,
Pharyngitis cellulitisPharyngitis cellulitis
b.Spore forming rods b.Spore forming rods
Aerobic Bacillus - AnthraxAerobic Bacillus - Anthrax
Anaerobic Clostridium - tetanus,gas gangreneAnaerobic Clostridium - tetanus,gas gangrene
botulism botulism
c.Non spore forming rods (c.Non spore forming rods (GRAM POSTIVE GRAM POSTIVE CONTD)CONTD)
1-Non filamentous1-Non filamentous Cornybacterium – Diphtheria Cornybacterium – Diphtheria
Listeria - meningitisListeria - meningitis
2.Filamentous 2.Filamentous Actinomycetes – ActinomycosisActinomycetes – Actinomycosis
Nocardia - NocardiosisNocardia - Nocardiosis
2.Gram negative2.Gram negative A.Cocci A.Cocci Neisseria -Gonorrhoea,Neisseria -Gonorrhoea, meningitismeningitis B.Rods B.Rods 1.Facultative1.Facultative a. Straighta. Straight 1.Respiratory org. 1.Respiratory org. Haemophillus- meningitisHaemophillus- meningitis Bordatella-Whooping Bordatella-Whooping
coughcough Legionella- PneumoniaLegionella- Pneumonia
2.2.Zoonotic Zoonotic Brucella – Brucallosis Brucella – Brucallosis FrancisellaFrancisella – –TularemiaTularemia Pasteurella –CellulitisPasteurella –Cellulitis Yersinia - PlagueYersinia - Plague
3.enteric & related 3.enteric & related ((GRAM NEGATIVE CONTDGRAM NEGATIVE CONTD))
E.coli - UTI,DiarrhoeaE.coli - UTI,Diarrhoea
Enterobacter – UTIEnterobacter – UTI
Serratia – PneumoniaSerratia – Pneumonia
Klebsiella – Pneumonia.UTIKlebsiella – Pneumonia.UTI
Salmonella – enterocolitis,typhoid feverSalmonella – enterocolitis,typhoid fever
Shigella – EnterocolitisShigella – Enterocolitis
Proteus – UTIProteus – UTI
b. Curvedb. Curved
Campylobacter – EntericolitisCampylobacter – Entericolitis
helicobacter – Gastritis,Peptic ulcerhelicobacter – Gastritis,Peptic ulcer
Vibrio - CholeraVibrio - Cholera
(Gram negative) (Gram negative) C.Aerobic C.Aerobic Pseudomonas – pneumonia,UTIPseudomonas – pneumonia,UTI D. Anaerobic D. Anaerobic Bacteroids – peritonitisBacteroids – peritonitis
3.ACID FAST 3.ACID FAST MYCOBACTERIUM -MYCOBACTERIUM - Tuberculosis & Leprosy Tuberculosis & Leprosy
B . Non free living obligate intracellular B . Non free living obligate intracellular parasitesparasites
1.Rickettsia1.Rickettsia – Rocky mountain spotted fever – Rocky mountain spotted fever
Typhus, Q feverTyphus, Q fever
2.Chlamydia 2.Chlamydia urethritis, trachoma. Psittacosisurethritis, trachoma. Psittacosis
Flexible thin walledFlexible thin walled Spirochaetes -Spirochaetes - Treponema – Syphilis Treponema – Syphilis
Borrelia – Lyme diseaseBorrelia – Lyme disease
Leptospira - leptospirosisLeptospira - leptospirosis
Wall- less cellsWall- less cells Mycoplasma - Mycoplasma - pneumoniapneumonia
Subtyping & Its applicationsSubtyping & Its applications To distinguishinguish between strains of different To distinguishinguish between strains of different
speciesspecies BiotypingBiotyping SerotypingSerotyping Antimicrobial susceptibility systemAntimicrobial susceptibility system Bacteriophage typingBacteriophage typing Bacteriocin typingBacteriocin typing
Genotypic Characteristics for Identifying Genotypic Characteristics for Identifying ProkaryotesProkaryotes
the use of genotypic testing has increased with the use of genotypic testing has increased with the availability of technologythe availability of technology
genotypic testing is particularly useful in the genotypic testing is particularly useful in the case of organisms that are difficult to identifycase of organisms that are difficult to identify
several techniques includeseveral techniques include gene probesgene probes PCRPCR sequencing rRNAsequencing rRNA
gene probesgene probes single stranded DNA that has been labeled single stranded DNA that has been labeled
with a identifiable tag, such as a fluorescent with a identifiable tag, such as a fluorescent dyedye
are complementary to target nucleotide are complementary to target nucleotide sequencessequences
• unique in DNA of pathogenunique in DNA of pathogen
PCR: polymerase chain reactionPCR: polymerase chain reaction used to detect small amounts of DNA present in a used to detect small amounts of DNA present in a
sample (blood, food, soil)sample (blood, food, soil) the PCR chain reaction is used to amplify the the PCR chain reaction is used to amplify the
amount of DNA presentamount of DNA present
Genotypic Characteristics used inGenotypic Characteristics used in Classifying Prokaryotes( non culture methods) Classifying Prokaryotes( non culture methods)
sequencing ribosomal RNAsequencing ribosomal RNA of particular use for identifying prokaryotes of particular use for identifying prokaryotes
impossible to grow in a cultureimpossible to grow in a culture focus is place on the 16S molecules of the RNA focus is place on the 16S molecules of the RNA
because of it’s sizebecause of it’s size• approximately 1500 nucleotidesapproximately 1500 nucleotides
once the 16S molecule is sequenced, it can then be once the 16S molecule is sequenced, it can then be compared to the sequences of known organismscompared to the sequences of known organisms
Genotypic Characteristics used inGenotypic Characteristics used in Classifying Prokaryotes Classifying Prokaryotes
comparison of nucleotide sequencescomparison of nucleotide sequences differences in DNA sequence can assist in differences in DNA sequence can assist in
determination of divergence of evolutionary path determination of divergence of evolutionary path for organismsfor organisms
DNA hybridizationDNA hybridization single strands of DNA annealsingle strands of DNA anneal
16S ribonucleic acid16S ribonucleic acid comparing sequence of ribosomal RNAcomparing sequence of ribosomal RNA
relatedness to other organisms can be determined relatedness to other organisms can be determined using using numerical taxonomynumerical taxonomy determined by the percentage of characteristics determined by the percentage of characteristics
two organisms have in commontwo organisms have in common