Transcript of Neisseria Meningitidis or Meningococcus (Gram Negative Coccus) | Med Zukhruf

the genus niceria contains two important human pathogens number one deny Syria meningitudes and the second one is niceria gonorrhea assalamualaikum lovely students today we are going to look at nice area meningitis but before getting started I like to tell you guys that these videos are met for educational purposes Banks and treatments may change with time if I get wrong or miss anything curing produce always welcome in the comments section so let's jump straight into the video Nigeria manager to this it's another name is meningococcus it is a gram-negative a diplococcus which means that two caucus occurs together and they form a pair just like the one you can see there a responsible for fermenting maltose and glucose that's why it is maltose glucose fermento as its name shows that it is responsible for causing meningitis disseminated meningocoxemia and the most severe form of meningococcemia is a life-threatening Waterhouse for Richardson syndrome and this bacterium belongs to the family nice series ACI it is catalase positive catalase is an enzyme released by certain bacteria and is not released by certain other bacteria for those of you guys who do not know what is catalase test catalase does what it can work hydrogen peroxide into water and oxygen and oxygen is possible for forming bubbles niceria being Catalyst positive will perform that test and some bacteria who are catalyzed negative like strep bacteria they will not perform that test means that they will not convert hydrogen peroxide into water and oxygen this bacterium is also oxidase positive it is an obligate aerobe and its facultative intracellular bacterium it does not produce beta-lactamase like the niceria gonorrhea does Nigeria gonorrhea produces the betalactamase like penicillinase because it has some strains that has resistance against the penicillin the antibiotic lecture outline as we're done with the introduction now we'll be looking at the morphology habitating transmission life cycle pathogensis clinical findings lab diagnosis treatment prevention and at the end as usual will review the lecture morphology this organism the neisseria meningitis it is oval and kind of kidney shaped it varies in size from 0.6 to 1 micrometer it is pink or red in color being gram-negative bacterium structure it has got thin peptidoglycan layer in its cell wall due to that it does not retain the dye and it stains pink or red it is an encapsulated bacterium it means that it has got a prominent polysaccharide capsule that plays a really important role in the virulence of this bacterium this bacterium also has an endotoxin in its outer membrane that is lipo oligosaccharide in contrast to the gram-negative rods especially the enteric ones who has got the Lipo polysaccharide this bacterium deny Syria meningitis is non-performing and non-motile as you can see in this picture this bacterium is a diplococcus it is pink in color and varies in size from 0.6 to 1 micrometer and it is overly in shape let's talk about the division of Nigeria meningitis as we know it is also called meningococcus This meningococcus is divided into at least 13 serologic groups on the basis of antigenicity of their capsular polysaccharides five stereotypes the a b c y and w135 they are really important because they are the most cases of meningitis and meningocoxemia habitate humans are the only natural hosts for meningococcus and this organism inhabits or colonizes the membranes of nasopharynx it becomes part of the transient floor of upper respiratory tract so if it is part of that so people having that in their normal flora are carriers of that organism and carriers are usually asymptomatic transmission Nigeria meningitis is transmitted by a respiratory or Airborne droplets like coughing or sneezing there are certain risk factors like patients with aceplenia may be functional or anatomic and patients with sickle cell anemia or patients having other encapsulated organisms like hemophilus influenza strep pneumonia are more susceptible to niceria meningitis infections pathogenesis we are going to start off with virulence factors the first one is iga1 protease that is immunoglobulin A1 protease it cleaves the mucosal IGA and the reason behind that is that healthy bacteria to attach to the membranes the mucous membranes of the upper respiratory tract in order to cause infection the second really high yield rear lens factor is polysaccharide capsule it is a anti-fagocytic that enables the organism to resist phagocytosis by polymorphonuclear leukocytes like neutrophils or macrophages this capsule is the immunogen and is used in certain vaccines against niceria meningitis the Third Wheel lens factor is lipo oligosaccharide endotoxin it's responsible for causing the release of cytokines like tumor necrotic Factor Alpha and interleukin-1 what happens when the endotoxin is released this causes fever shock and other pathophysiological changes the fourth spirulence factor is adhescence they promote bacterial attachment and prevent lymphocyte activation the fifth spirulence factor is Factor H binding protein what does it do it reduces oxidization activity okay let me explain that to you factor Edge binding protein present on the meningococcus binds to the factor H an inhibitor of complement Factor c3b the the presence of factor h on the surface of meningococcus reduces the oxidization activity of c3p and reduces the amount of membrane attack complex produced Factor Edge binding protein is also an immunogen that is also used in certain vaccines that work against niceria meningitis as I told you that polysaccharide capsule is really high yield when it comes to realness factors let me explain that to you normally what happens when a bacterium enters a human body its membrane is tagged it means that bacterium is tagged with IGG oc3b and this tagging process is called optimization and after that what happens that signals are sent to spleen to send your macrophages for phagocytosis explain sends these planic macrophages they come and phagocytose the organism human body relies on opsonization and phagocytosis both in order to get rid of the infection what happens when there's no spleen as in case of overwhelming postplanctomy infection because plane has been removed there will be no phagocytosis only opsonization cannot take the bacterium out of the human body so what will happen that bacteria will increase its number and increased number of bacteria will definitely cause a more severe infection and this type of infection is called overwhelming systemic infection other kinds of encapsulated organisms that I told you like people having such encapsulated organisms are susceptible to infections caused by niceria meningitis these organisms are strep pneumonia I do have a detailed video on that bacteria if you want to know more about that browser channel the second encapsulated organism is hemophilus influenza and the third one obviously the one we're discussing today is nicerial meningitis the type of pathogenesis will be pyogenic okay let's talk about what happens when the bacterium the meningococcus enters from nasopharynx it then attaches to the nasopharynx mucosa via pilai it then enters the blood and spread to specific sites such as meninges or joints or be disseminated throughout the body causing meningocoxemia nyseria meningitis is responsible for causing certain diseases most common of them is the community acquired meningitis but it can also cause meningocoxemia that in its severe form is Waterhouse Richardson syndrome as we know that the hematogenous spread of bacterium occurs for disseminated infections so definitely they will be bacteremia let's talk about meningitis meningitis is caused by a nice area meningitis when when it enters the brain after entering the brain it crosses the blood CSF barrier the cerebrospinal fluid barrier then it enters the CSF and we replicates their and causes inflammation of the surrounding manages these ones okay memorizing meningitis has become so easy with these three steps entering into the brain after entry what happens crossing a CSF barrier then replicating in the CSF and causing inflammation of the managing disseminated meningocoxemia nyseria manager today spreads via blood in whole body it releases lipo oligosaccharide endotoxin that has massive inflammatory response that results in increased capillary permeability and activation of coagulation this causes disseminated intravascular coagulation also called DIC now as we know there's a coagulation problems so coagulation consumes the platelets resulting in thrombocytopenia what's thrombocyte opinion decreased amount of platelets so decrease playlist leads to increased bleeding tendency this will present as potential rash over the trunk or lower limb or extremities and damage to epithelial cells along with increased capillary permeability leads to leakage of blood this will cause generalized hypovolemia or hypovolemic shock Waterhouse friedrichin syndrome it is an inflammatory response in small blood vessels of adrenals present at the top of kidneys that results in endothelial damage and rupture of blood vessels due to DIC the disseminated intravascular coagulation clotting is hard that leads to leakage of blood in interstitial space of adrenals the adrenal glands right this along with generalized hyperperfusion leads to ischemia and necrosis of the gland this ultimately causes adrenal insufficiency also known as addisonian crisis clinical findings community she acquired bacterial meningitis presents with fever headache photophobia nuclear rigidity and altered mental status let's talk about nuclear rigidity we can assess a by these two signs first one is chronic sine there will be flexion of thigh and extension of knee and this will cause pain in the knee this is positive chronic signs it means that there's nuclear rigidity the second one is bruzinski's sign when there is a reflexive hip flexion so head will be elevated this is positive brzezinski's neck sign Waterhouse friedrichen syndrome it will present as fever having adrenal gland hemorrhagic necrosis to that many nutrientoscular coagulation thrombocytopenia there are petition or the popular present on trunk or the low extremities functional Addison's crisis hypovolemic shock is also present lab diagnosis is we'll need samples of blood and spinal fluid these cerebrospinal fluid CSF on microscopy it is revealed that this bacterium is gram negative because of pink or red color after this training this bacterium is avoid in shape or kidney shaped it is 0.6 to 1 micrometer in size as you can see there this one is diplococcus culture Nigeria meningitis is cultured on chocolate agar not blood agar we are going to talk why not blood and the chocolate agar is incubated at 37 degrees Celsius and 5 carbon dioxide colony is formed will be smooth around moist uniform large they are gray or brown in color and they have a glistening surface the shiny surface why not blood agar why the chocolate egg the reason behind is that the growth of Nigeria meningitis is inhibited by certain toxic Trace metals and fatty acids present in blood agar when this blood agar is heated these toxic Trace metals and fatty acids get inactivated that leads to the growth of the bacterium on that agar and after the heating of blood agar 8 becomes the chocolate agar so chocolate agar is actually the blood agar just heated up others will also go for sugar fermentation like of maltose and glucosal look if this bacterium does so it is niceria meningitis immunofluorescence can also be used to identify these species however a procedure that can exist in the rapid diagnosis of meningococcal meningitis is the latex agglutination test which detects capsular polysaccharide in the spinal fluid and on blood tests we'll find out that there's an increased level of polymorphonuclear leukocytes treatment as we know that niceria meningitis does not release the beta-lactamase for example the penicillinase so we can use pan Amazon G for its treatment or infections caused by it and we can also use third generation cephalosporins like Ceftriaxone for the treatment of infections caused by Nigeria meningitis will also use refurbate prevention chemo prophylaxis and immunization both are used to prevent meningococcal diseases there are certain vaccines that work against infections caused by nice area manager to this and these are classified into two number one vaccines that work against Acy w135 stereotypes and the second one that work against The Stereotype B the ones that work against the acyw-135 stereotypes are further subdivided into conjugated and unconjugated vaccines and the one for B zerotype are further classified into Factor H binding protein vaccines and certain other surface proteins we're going to look at them the conjugated and unconjugated are those vaccines they've got no B polysaccharide and they are not immunogenic while the ones against serotype B both have surface proteins the conjugated vaccine has a capsular polysaccharide and that capsular polysaccharides is conjugated to a carrier protein but in unconjugated vaccine there's no such conjugation there is high antibody Titus in Children of conjugated vaccines but of unconjugated waxing there's no such uh increased title and children are wearing from 11 to 12 years of age College children and travelers they definitely are recommended to have conjugated vaccines but unconjugated vaccine is recommended for children aging about 11 years fhbp means Factor Edge binding protein and that one is immunogenic and this Factor h block c3b binding others include an ADA that is nicer real it has an a the second one is nhba that is my serial Heparin binding antigen next one is OMB that is outer membrane vesicle or pole a let's talk about the further classification of vaccines conjugated vaccines are further classified into four forms menactra that contains four polysaccharides conjugated to diphtheria toxoid as carrier protein the second one is menview that contains the four polysaccharides conjugated to a non-toxic mutant of diphtheria toxin as the carrier protein the third one is men hybrids that contains two polysaccharides the C and Y plus the capsular polysaccharide of hemophilus influenza all conjugated to tetanus toxoid next one is men every rack that is used in meningitis belt of Africa it is a conjugate vaccine that contains only group a polysaccharide the unconjugated men immune vaccine it contains only four polysaccharides and they are not conjugated to a carrier protein as we've discussed earlier there's conjugation to a carrier protein and conjugated vaccines and there's no conjugation to a carrier protein and unconjugated vaccines the example of the vaccine of fracture Edge binding protein is schumenba and for the other ones it's back zero alright guys let's wrap up everything in this short table the organism we discussed today is niceria meningitis it is responsible for causing meningitis meningocoxemia Waterhouse Richardson syndrome and don't forget bacteremia it is transmitted via respiratory or Airborne droplets humans are the only hosts and it colonizes the nasopharynx its diagnosis is based on gram staining microscopy culture sugar fermentation test and also oxidase test and Catalyst test it is treated with third generation cephalosporins refound pain and penicillin gene that's it hope you enjoyed it if you've got any suggestions feel free to leave them Below in the comments and I'll meet you soon assalamualaikum