Introduction to Medical MicrobiologyDr Mila Nu Nu HtayObjectives Importance of microorganismsHow to apply knowledge of microorganismSpontaneous generation VS biogenesisGerm theory of diseaseNaming and lassifying microorganisms!a"omonic arrangement#odern developments in microbiology$merging infectious diseases#icrobes in Our %ives#icroorganisms are organisms that are too small to be seen with the unaided eye&'Germ( refers to a rapidly growing cellicrobiology)erived form 'Greek(Study of the microscopic organisms&Scale of #icrobesScale of #icrobes#icroorganisms *Importance+)ecompose organic waste , they free up nutrients from no longer living sourcesicroorganisms *Importance+-re energy producers in the ecosystem by photosynthesis#icroorganisms *Importance+.roduce industrial chemicals such as ethanol and acetone#icroorganisms *Importance+.roduce fermented foods such as vinegar/ cheese/and bread#icroorganisms *Importance+.roduce products used in manufacturing *e&g&/ cellulase+ and treatment *e&g&/ insulin+0nowledge of #icroorganisms-llows humans to , .revent food spoilage0nowledge of #icroorganisms-llows humans to ,.revent disease occurrence0nowledge of #icroorganisms%ed to aseptic techni1ues to prevent contamination in medicine and in microbiology laboratories&- 2rief History of #icrobiology$"istence of microorganisms was hypothesi3ed for many centuries before their actual discovery&Since 4th centuryIn 5674 8 Girolamo 9racastoro proposed that the epidemic diseases were caused by transferable seedlike organismsthat could transmit by direct or indirect contact&$arly claims are speculative and not based on microscopic observation&!he 9irst ObservationsIn 5446/ :obert Hooke reported that living things were composed of little bo"es or cells&!he 9irst ObservationsAntoni van Leeuwenhoek (1673-1723)In 54;4/ he used a single,lens microscope of his own designdescribed live microorganisms that he observed in teeth scrapings/ rain water/ and peppercorn infusions&single,lens microscope!he )ebate Over Spontaneous Generation!he hypothesis that living organisms arise from nonliving matter is called spontaneous generation& -ccording to spontaneous generation/ a 'vital force( forms life&!he alternative hypothesis/ that the living organisms arise from pree"isting life/ is called biogenesis&$VI)$N$S< .:OS = ONSSpontaneous Generation16th century #any scientists believe that some forms of life could arise from nonlife17!" >ohn Needham put boiled nutrient broth into covered ?asks resulted to microbial growth#heory o$ %iogenesis 166& 9rancisco :edi @lled si" jars with decaying meat resulted to maggots growth in uncovered jars 176" %a33aro Spallan3ani boiled nutrient solutions in ?asksand removed air which resulted to no microbial growth 1&61 %ouis .asteur demonstrated that microorganisms are present in the air& A'' 'i$e is $ro( pre-e)isting 'i$e$vidence .ro and on5A45< %ouis .asteur demonstrated that microorganisms are present in the air&Conditions ResultsNutrient broth placed in flask, heated, not sealedMicrobial growthNutrient broth placed in flask, heated, then sealedNo microbial growthBiogenesis$vidence .ro and on.asteurBs S,shaped ?ask!he Golden -ge of #icrobiology5A6;,5C572eginning with .asteurBs work/ discoveries included the relationship between microbes and disease/ immunity/ and antimicrobial drugs9ermentation and .asteuri3ation.asteur showed that microbes are responsible for fermentation&*er(entation is the conversion of sugar to alcohol to make beer and wineicrobial growth is also responsible for spoilage of food&2acteria that use alcohol and produce acetic acid spoil wine by turning it to vinegar *acetic acid+&9ermentation and .asteuri3ation.asteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine& +asteuri,ation is the application of a high heat for a short time&*alcohol beverage and milk+ 8 ;D E/ 56 sec&!he Germ !heory of )isease5A7Fs< Igna3 Semmelweis advocated hand washing to prevent transmission of puerperal fever from one O2 patient to another&!he Germ !heory of )isease5A;4< :obert 0och proved that a speci@c microbe causes a speci@c disease&!he Germ !heory of )isease5A4Fs< >oseph %ister used a chemical disinfectant to prevent surgical wound infections after looking at .asteurBs work showing microbes are in the air/ can spoil food/ and cause animal diseases&Vaccination5;C4< $dward >enner inoculated a person with cowpo" virus& !he person was then protected from smallpo"&Vaccination is derived from vacca for cow&!he protection is called immunity&Naming and lassifying #icroorganisms%innaeus established the system of scienti@c nomenclature&$ach organism has two names< the genus and speci@c nameScienti@c Names-re '%atini3ed( and used worldwideay be descriptive or honor a scientist&Scienti@c NamesStaphylococcus aureus, )escribes the clustered arrangement of the cells *staphylo,+ and the golden color of the colonies *aur,+&Scienti@c NamesEscherichia coliHonors the discoverer/ !heodor $scherich/ and describes the bacteriumBs habitat8the large intestine or colon&2inomial NomenclatureExamples: Escherichia coli, E. coli, Escherichia spp., and the genus EscherichiaThe genus name (Escherichia) is always capitalizedThe species name (coli) is never capitalizedThe species name is never used without the genus name (e.g., coli standing alone, by itself, is a mistake!)2inomial NomenclatureExamples: Escherichia coli, E. coli, Escherichia spp., and the genus EscherichiaThe genus name may be used without the species name (e.g., Escherichia may stand alone, though when doing so it no longer actually describes a species)hen both genus and species names are present, the genus name always comes first (e.g., Escherichia coli, not coli Escherichia)2inomial Nomenclature !oth the genus and species names are always italicized (or underlined)"always underline if writing binomials by hand#fter the first use, it may be abbreviated (e.g., E. for Escherichia) though this is done typically only when used in combination with the species name (e.g., E. coli)The species name (e.g., coli) is never abbreviatedlassi@cation of #icroorganismsomparing )omains2acteria.rokaryotes.eptidoglycan cell walls2inary @ssion9or energy/ use organic chemicals/ inorganic chemicals/ or photosynthesisFigure !a:od,Shaped 2acteria *2acillus+Spherical 2acteria *occus+Spirochete:Borrelia burgdor

eriSpiral,Shaped 2acteria-rchaea.rokaryotic%ack peptidoglycan%ive in e"treme environmentsInclude"#ethanogens"$"treme halophiles"$"treme thermophilesFigure #!$b9ungi$ukaryoteshitin cell wallsGse organic che(ica's for energy&Heasts are unicellularolds and mushrooms are multicellular consisting of masses of mycelia/ which are composed of @laments called hyphae&Figure !b-lgae$ukaryotesellulose cell wallsGse photosynthesis for energy.roduce molecular o"ygen and organic compoundsFigure !d.arasiteA parasite: a living organism that acquires some of its basic nutritional requirements through its intimate contact with another living organism. Parasites may be simple unicellular protozoa or complex multicellular metazoaProtozoa: unicellular organisms, e.g. Plasmodium (malaria Metazoa: multicellular organisms, e.g. helminths (worms An endoparasite: a parasite that lives within another living organism ! e.g. malaria, "iardiaAn ectoparasite: a parasite that lives on the external surface of another living organism ! e.g. lice, tic#s.roto3oa$ukaryotes-bsorb or ingest organic chemicals#ay be motile via pseudopods/ cilia/ or ?agellalassi@ed by the method of locomotionHave comple" cellsFigure !c#ulticellular -nimal .arasites$ukaryote#ulticellular animals.arasitic tape worms and round worms are called helminths&Figure %!%&aViruses-cellularonsist of )N- or :N- coreore is surrounded by a protein coat *caspid+&oat may be enclosed in a lipid envelope&Viruses are replicated only when they are in a living host cell&Figure !eViral si3e)etermined with the aid of electron microscopy :ange from DF to 5FFF nm in length&Other '-gents(!a"omonic -rrangement2acteriology 8 the study of bacteria&Virology 8 the study of virusesycology 8 the study of fungi&.roto3oology 8 the study of proto3oa&.hycology *algology+ 8 the study of algae&.arasitology 8 the study of parasites&Immunology 8 the study of immune systemodern )evelopments in #icrobiology#icrobial genetics , the study of an organismBs genes/ have provided new tools for classifying microorganisms&!he 2irth of #odern hemotherapy!reatment with chemicals is che(otherapy&hemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics&Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes&!he 2irth of #odern hemotherapyIuinine from tree bark was long used to treat malaria&!he 2irth of #odern hemotherapy5CDA< -le"ander 9leming discovered the @rst antibiotic&He observed that Penicillium fungus made an antibiotic/ penicillin/ that killed S. aureus&5C7Fs< .enicillin was tested clinically and mass produced&Figure !$#odern )evelopments in #icrobiologyImmunology is the study of immunity& Vaccines and interferons are being investigated to prevent and cure viral diseases&Figure !# '( of ()#odern )evelopments in #icrobiologyVirology is the study of viruses& :ecombinant )N- is )N- made from two diJerent sources& In the 5C4Fs/ .aul 2erg inserted animal )N- into bacterial )N- and the bacteria produced an animal protein#odern )evelopments in #icrobiology:ecombinant )N- technology/ or genetic engineering/ involves microbial genetics and molecular biology&Vaccines/ human hormones/ drugs#odern )evelopments in #icrobiologyGsing microbes"George 2eadle and $dward !atum showed that genes encode a cellBs en3ymes *5C7D+odern )evelopments in #icrobiologyGsing microbes"Oswald -very/ olin #ac%eod/ and #aclyn #carty showed that )N- was the hereditary material *5C77+odern )evelopments in #icrobiologyGsing microbes" 9rancois >acob and >ac1ues #onod discovered the role of m:N- in protein synthesis *5C45+&2ioremediation *micorbial biodegrdation+2acteria degrade organic matter in sewage&2acteria degrade or deto"ify pollutants such as oil and mercury&*N %!2iological Insecticides#icrobes that are pathogenic to insects are alternatives to chemical pesticides in preventing insect damage to agricultural crops and disease transmission&Bacillus thuringiensis infections are fatal in many insects but harmless to other animals/ including humans/ and to plantsodern 2iotechnology and Genetic $ngineering%iotechno'ogy/ the use of microbes to produce foods and chemicals/ is centuries old&Genetic engineering is a new techni1ue for biotechnology& !hrough genetic engineering/ bacteria and fungi can produce a variety of proteins including vaccines and en3ymes issing or defective genes in human cells can be replaced in gene therapyicrobes and Human )isease2acteria were once classi@ed as plants giving rise to use of the term fora for microbes&!his term has been replaced by microbiotaicrobes normally present in and on the human body are called nor(a' (icrobiota&Normal #icrobiotaNormal microbiota prevent growth of pathogens&Normal microbiota produce growth factors such as folic acid and vitamin 0&:esistance is the ability of the body toward oJ disease& :esistance factors include skin/ stomach acid/ and antimicrobial chemicals&.robiotics2acteria potentially bene@cial to the digestive system& *lactic acid bacteria/ bi@dobacteria+Substances consumed to promote the growth of probiotic microorganisms&*soybeans/ raw oats/ unre@ned wheat/ unre@ned barley+.rebiotics$merging Infectious )iseasesKest Nile encephalitis"Kest Nile virus"9irst diagnosed in the Kest Nile region of Gganda in 5CL;"-ppeared in New Hork ity in 5CCC$merging Infectious )iseases2ovine spongiform encephalopathy".rion"-lso causes reut3feldt,>akob disease *>)+$merging Infectious )iseases Escherichia coli O6;