hello everyone sir larry here so for the last topic of our clinical bacteriology prelims it is included on your examination we have your microbial mechanisms of pathogenicity and principles of disease epidemiology the story classes on this topic uh i will make sure that this will be just a short since these are some additional informations on the mind that will be added on your language in terms of pathology so let's start so for the learning outcomes of this discussion first ones we're going to define terms that is being related to microbial pathogens and epidemiology second one correlate factors of pathogenicity and virulence when the clans were going to compare as well as correlate their importance with each other as well as their distribution and their connection okay third one discuss the mode of transmission of bacterial infections as well as therapy infections or the route of entry as well as the around class for portal effects so this is just basically class a sort of review when it comes to the transmission as well as the at some point the chain of infection okay so as you have already know tesla that we do have portals of npms importance of anti-clash it is how associated microorganisms are not only limited to our bacteria but also to other other but also cast our other microorganisms so this is how microorganisms class can enter our body not by means of mucosa for example our eyes okay um skin also so microorganisms can enter class for example there are some open wounds okay on our skin that can serve as a portal of entry of these microorganisms and we also have our internal roundup mode of energy glass of our bacteria or our microorganisms portals of exit nomenclature means to say how a certain microorganism that is present on that certain person can be transmitted or can exit the body class okay so we have two respiratory tracts by means of coughing plus or sneezing so infections can be transmitted that is why glass it is very important right now now that we are able to know what are the proper way you know of up coughing of sneezing specifically class if we are on a public area in as soon as possible class we are going to cover our mouths or our noseless nose every time we do tough or we do sneezes just say we really don't know let's know that us no can be a source of infection by means of coughing or by means of sneezing okay faces also can be a means of portal of exit as well as a saliva parasitology class most commonly of exit or mode of transmission of your rock of your parasites class i means a fecal oral round okay or at some point whether in contamination specifically food products if i will prepare no product less uh i'm not able to follow proper way of um preparing it or cooking it so let's see so that can be a possible way class of transmission of infection saliva also can be a mean of importance of exhibit aside from the class urine and also some vaginal secretions now specifically class for those sexually transmitted infections kinase or vaginal sufficient class not only limited nervous dysfunction institutions but also to penal situations class mde um portal of exit of our microorganisms and also skin class so skin can be both a portal of entry as well as a portal of exits of our microorganisms okay so it's basically the microbial mechanisms class of pathogenicity in which how certain microorganisms can be transferred or can be get caused by other persons next we're talking about class about your microbial virulence factors so that's what i have mentioned now specifically to some of my students certain virulence factors are toxins or some proteins that are present on your microbial on your bacterial structure class that can serve as their defense mechanism because against microbial virulence factors they are providing this microorganisms with the capacity to avoid host defenses and damage host cells glass tissues and organs in a number of ways so for example is your capsule we do have bacterias that have capsule under structures so also at some point classic that bacteria has a capsule our um cells or our wbc's specifically those pagocytic cells are finding a hard time in terms of swallowing this bacteria that do have capsules because again class a the capsule of your bacteria will help your your bacteria cholesterol in terms of um defensing its or defending class its structure that deletion is so that's one of an example directory class you see during on our midterms we're going to discuss a lot of virulence factors of different bacterias okay organisms with the capacity to avoid host defenses and damage host cells class no so aside a class from being defending their selves class in terms of uh being destroyed by our phagocytic cell they can also cause damage glass small cells okay so we also have here some adhesions and ligands present on our bacterias for example try different just to familiarize these things so your glycogens possessed by receptors mutants your m-protein class is a virulence factor of receptors pyogenes your opa protein class is for your necessity and your tapered end so the [Music] physical or the gross appearance of your treponema plus our spirochetes together with your uh borelia as well as well as relaptospyra so vitraponema class is a spiral kids that have a are usually associated with your i call this sore throats like this then because of that infection now we also have some enzymes gesso that are vital and swap perspirant of your bacterias for example you have your coagulase so this enzyme class can coagulate the blood those of your kindness that digest fibrinoglax your hyaluronidase that hydrolyzes hyaluronic acid and they also have glassware collagenase that hydrolyzes collagen network class has in-depth discussion on what uh their function or what's their use class will be introduced to you during your midterms now specifically going to discuss class specific based on their pathogenicity as well as their virulence next one toxins toxins are being produced by your same thing tbs we'll have here your toxigenicity which refers to us the ability of microorganisms to produce toxins okay we also have here toxemia class so immune you're gonna see emia that's a suffix for blood that there is a presence of toxin in the host blood okay we also have here anti-toxin so antitoxin class are antibodies produced by our bodies against a specific toxin so it's amazing because of the thing that our body has able to produce antibodies a lot of antibodies for different infections okay so we have here class two types of toxins so with introduction regarding with this we have your exotoxins and your endotoxins okay when you say exotoxins means the outside okay they are being produced less now by your bacteria mostly ground positive bacteria as part of their growth and metabolism and they are then secreted glass or released following lysis into the surrounding tube so you can just exotoxin reproduce inside but they are being released let's know by your bacterias outside okay following class elise's into the surrounding next one we also have here glasser endotoxin which are part demand of the outer portion of the cell wall of your mostly gram-negative number bacterias so they are being liberated last when the bacteria die and the cell wall breaks apart so it's different from from your eggs exotoxins found inside released outside your endotoxin class can be found outside which are again liberated let us know when your bacteria dies or if the cell wall of that bacteria glass breaks up okay next let's suppose it lasts to some um definitions here regarding the principles of your decisions so in c pathology study of disease okay etiology i'll decide to familiarize this class this definitions or these words and what are they are so ethiology the study of the cause of the disease your pathogenesis is the development of the disease the infection the pathogenic colonization of the body if a certain microorganism is present also because if there is certain microorganisms and their number has increased that can cause infection this is also known as which is which is a abnormal state in which the body class is not normally functioning so that's the normal metabolism of your body being occurred because there's a disease that is happening on that body okay so pathology disease pathogens say pathogens less these are disease causing microorganisms again no not limited to bacterias but also your vitamins as well as your fungi and your parasites you also have your class the hosts know in which the microorganisms class shelters and supports the growth of your pathogens infections again invasions or colonization of the body by pathogenic microorganisms and another definition of fertilisers is that there is a change in the state of health okay again your body is not functioning for a normal state okay a normal statement class in which a part of the whole or a part class or the whole body is a properly adjusted or nor functioning properly another definitions here the extent of your host involvement so there are different types of infections your local infections the c-class local functional pathogens are only limited to a small area of the body for example on the foot area infection depends on that area when they say systemic infection class an infection it is all or through outlast body opal infection class are just systemic infections that began as a local infection mean to say cluster increase and you have area in which included nasal infection that's your focal infection okay so what class is just a bacterial present in the blood except this minimum class are growth of your bacteria in the blood let's be confused with your bacteria this is the presence of bacteria in the blood when you see septicemia class a systemic infection in which the bacteria already outnumbered okay your uh your wbcs or your phagocytic cells no that causes the septicemia system systemic infection and like with your bacteria that there's only a presence of bacteria on our blood or in the blood okay so again that we can fix glass because it's different and like with our urine and like with our uh our stool that it has normal floras our bacterias are i mean our blood glass are sterile bacteria so a presence of bacteria in our blood came right down okay next phenomenon again the presence of toxins in the blood okay so we also have here primary infections these are acute infections that causes the initial illness you say secondary infection class are opportunistic infections after a primary infection for example primary infection is like or coughing or sneezing and uncurrent alcohols or cough consequent infection causes can above minimal immune system other opportunistic bacterias are opportunistic microorganisms class yes infection okay so after class a primary infection there will be a secondary infection we also have sub-clinical disease no notice no no noticeable class sign and symptoms in apparent to an infection so now we have here the table gesture of your normal of your normal microbiota so you have transcend microbiota your normal microbiota class and your opportunistic microbiota okay also here is symbiotic relationship i know that you're already familiar with this point your commensalism mutualism is a commensalism class one orga one organism class benefits and the other is unaffected okay we say mute police abdomen class both of them plus benefit with one another and this abdomen has only one benefit okay at the expense of the either music less affected than is something that is happening on that certain um group of people infected with parasites that's parasitism unlike their commerce commensalism either is benefiting okay but the other one is unaffected okay so we see normal microbiota plus these are microorganisms that are established permanent colonies inside or in the body without producing disease these are our normal florence glass okay our skin our agave intestinal tract our mouth all of us glass astonishment flora in which this bacterious cluster that are present in our body cannot cause infection they're not able to produce disease class okay unlike with your transient cluster microbiota these are microbes that are present for various periods then disappear okay so our normal microbiota class have several beneficial effects for our body not specifically for our body's function for our body's metabolisms case first one is it prevents the growth of our pathogens by occupying niche that pathogens might occupy okay second one it produces growth factors such as folic acid and vitamin k and which again help fulton class attained by this metabolism and as well as probiotics so the last okay let's wanted to add this class regarding your epidemiology so sort of you learn that your epidemiology class is the science that studies when and where diseases occur and how okay this is these diseases class are being transmitted in a certain population you