Exam Recall Series (INI-CET May '26) - Microbiology

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[00:00:00]So hello everyone hope all of you have done your exams well. So with that I hearty welcome all of you to INST May 2026 microbalgia recall. So myself Dr. Abdul Nasir your doctor blueprint. So here is the first question. Sir before we begin you need to know I have arranged the questions in in order which is matching with the order of world of revision videos. So whether the first question is digestion and concentration of spudum sample is done using. Sir first of all you need to know what do you mean by digestion and contamination and why we have to do for for sputum sample you know sputum sample is mucoid in nature as it is mucoid in nature difficult to collect the sample that's why we have to liquefy the sputum and second sputum sample contains solos non pathogenic organisms we have to kill them before we put it on the culture media to isolate pathogens so we have discussed in the class in the videos that only two types of samples contain commensols one is tool sample one is pum sample if you see the world of revision The notes sir in the page number four we have discussed that stool sample contains commensols and the stool commensols are inhibited by using enrichment media and sputum samples alo sample also contain commensols and in sputum sample commensols are inhibited by using NALC and NaOH method. Naalc means nacetyl lcistine that liquefies the sputum. NaOH is sodium hydroxide which is a disinfectant that can kill the commensols in the spoolum sample. So clearcut the answer is NALC and NaOH method right. So NALC and NAO method is the answer for the digestion and decontamination of sputum sample. Very easy to answer. So if you see the second question sir the virulence factor of basilus anthraasis responsible for resistance to fagocytosis is it capsule?

[00:01:46]Which of the following is correct biochemical composition? Sir, what they're asking is the biochemical composition of the capsule.

[00:01:53]For that if you see the right videos that is the first topic general microbiology. Sir in general microbiology there is a topic what you have discussed capsular detection. In the topic we have discussed what is that sir polyeptide capsule is present in basilus anthrais and other bacteria they have polysaccharide capsule. That is the important point. So only basilless anthraasis is having polyeptide capsule as we know this. Now come back to the question. See the options. Sir polysaccharide capsule ruled out.

[00:02:22]Polysaccharide capsule ruled out.

[00:02:24]Glutamic acid capsule is nothing but polyeptide capsule because you know glutamic acid is amino acid and amino acid forms the protein and protein containing capsule is polyeptide capsule. So easily I can rule out A and C because we all know baseline is having polyeptide capsule. Now we have to decide whether the answer is B or D. So the difference here is PX1 gene and PXO2 gene. So now we have to decide the genes also. So first you have to decide the capsule. Then you have to decide the gene. Which gene is coding for the capsule. You know PX1 gene is coding for anthrax toxin. Anthrax toxin and PXO2 gene codes for capsule. Codes for capsule. And that's why the answer here is option D. That is the right answer.

[00:03:09]So moving on to the next question. Sir a patient a patient with symptoms of fatigue palar and microitic anemia under go stool microscopy examination as shown below. So stool microscopy has shown this egg. Which among the following statement is correct? Sir, we have to search for true statement. So this is the egg of which parasite? For that if you see the notes page number 53 there clearly same image is there and in this image we have discussed the egg containing blastome inside these round structures inside the egg are nothing but blastome inside the embryo and when you see blasto inside the embryo you know the answer is this is the egg of ankylo negator hookworm egg. So now with this we came to know okay this is a hookworm egg hookworm means ankylo or negator ankylo negator so with that I will rule out option c and option d because it can't be the egg of ascaris can't be the egg of introbasicularis because I came to know this is the egg of ankylo nega now now I have to decide the option between a and b a and b s penetration of skin consumption of contam so they're asking whether the mood of infection is skin penetration or injection for that again Right? In the videos if you have seen sir the in the notes page number 16 we have written which and all the parasites enter where skin penetration you know helm usually they enter by injection only three of them they enter where skin penetration sir we have I have given the pneumonic ssa what is ssa systoloidis and ankylo enter where skin penetration systoma is a tramode and strongoid and ankylo are neatodes so with that we came to know ankylo enters where Skin penetration. Sir, we got the answer.

[00:04:52]Ankallo stoma enters where skin penetration. Option A is the right answer. Sir, moving on to the next question. If you see the next question, identify the false statement regarding the apparatus shown in the image. Sir, we have to search for false statement.

[00:05:04]What to search is important regarding what regarding this apparatus. Sir, what is this apparator? Sir, if you don't know which is this apparatus, then see the options, you will get some clue.

[00:05:12]Sir, uses uses baselis stereothermop as indicator. Consider you don't know about it. Moist heat above 100°C are working principle sir I know 100°C above 100°C okay sir 121° C 15 lbs pressure 15 minutes this will say this is autoclave this will say sir this is the question from hospital infection control right in hospital infection control if you have seen page number 18 or 19 there we see auto clay moist heat method auto clay 121°C 15 minutes 15 psa pressure see same 121°C 15 psi pressure and for 15 minutes basilus stero thermopilis is used as controller indicator.

[00:05:56]So with this I came to know this is the temperature what is used this is moist heat method and geiobas thermopl is the indicator. So with that I can say now uses geiobas thermopl is the indicator.

[00:06:06]True statement moist heat above 100°C.

[00:06:09]Yes statement because it is 121°C. So above 100 is a true statement. Then I came to know first two statements are true. Now I have to decide which is false among C and D. Sir, if you see the C, temperature 1215 lb is pressure for 15 minutes. Temperature is right. But what they're asking is at this temperature biopsy instruments used in a patient suspected of cruel Jacob disease. So Cruzfield Jacob disease is a pryion disease.

[00:06:37]Pryion disease. They're asking prons are killed at this temperature or not.

[00:06:42]Remember at this temperature spores are killed. Spores are killed but pions are not killed. Pions are the most difficult to get killed. Difficult than spores.

[00:06:52]Difficult than spores. So this is the normal temperature of autoclave which kill till spores. To kill the prons we have to increase the temperature of autoclave from 121 to 134°C and the time of autoclave from 15 minutes to 18 to 20 minutes. Then only prons gets killed at this temperature.

[00:07:11]Pon autoclave can kill prons but not at this temperature. So this is the option C is the false statement. Then obviously BI dig test is used for air clearance.

[00:07:20]True statement and that's why our answer is option C. Option C. So without moving on to the next question. So next question. A 28-year-old woman presented with fever, diffused arithmatus, rashes and hypotension. She is currently on her menstrual cycle and using tampons. Some menstrual cycle bleeding is there using tampons. See prolonged use of tampons.

[00:07:42]Remember it is associated with toxic shock syndrome.

[00:07:46]Prolonged use of tampons is associated with toxic shock syndrome. So by menstrual cycle using tampons without they're telling patient is having toxic shock syndrome and you know we have discussed in the class notes in the chapter imun immune immunity or immunology in the antigen topic that toxic shock syndrome toxic shock syndrome is caused by staff orius and streptococcus bio genes by producing toxic shock syndrome. toxin or pyrogenic exotoxin and both are what? Both are super antigens. And what are super antigens? See here they have given orange color normal antigen, black color super antigen. And what they have given is sir what we have discussed is so normal antigen that is orange color binds between alpha chain and beta chain of the receptors. Whereas this black color super antigen binds to the beta chain beta chain directly binding to the beta chain of the receptors and the receptor is MSC2.

[00:08:42]So MSC2 receptor binding to beta chain is a super antigen and that is what is given here clearly MHC2 binding to beta region of the receptor.

[00:08:52]Option D you got the right answer the right. So tampons toxic shock syndrome.

[00:08:57]Toxic shock syndrome caused by super antigen and super antigen bind to MS2 receptor to beta antigen. The question is on super antigen. Sir moving on to the next question sir identify the labels marked as 1 2 3. Right? Where is 1 2 3. Before I show where is 1 2 3 sir.

[00:09:13]First of all sir what is this? This is a antibbody. Very good. You know the basic structure of the antibbody sir.

[00:09:19]Antibbody consists of heavy chains and light chains. So these longer chains are heavy chains. This is one heavy chain.

[00:09:27]This is second heavy chain. There are two heavy chains. And you know these heavy chains held each other with the dulfide bond. That is dulfide bond. They held each other. They hold each other with dulfide bond. Two heavy chains, right? Holding each other with dulfide bond. And at the same time you need to know there are two light chains. There are two light chains. See these are the light chains. One light chain. Second light chain. two light chains. Light chains are holding heavy chains with a dulfide bond. See this is the dulfide bond.

[00:10:01]Two heavy chains holding each other with dulfide bond and two light chains holding heavy chains with the dulfide bond. You should have this idea. This is the basic structure of the antibbody.

[00:10:11]And next idea what you should have is this region, right? This region is known as hinge region. This region is known as hinge region. Okay, once you know this structure of antibbody, now you need to know three things that can liice the antibbody. So, which are the three things that can liice the antibbody? One is pepine, second is pepsin and third is mercaptoethanol.

[00:10:35]Pepin, pepsin, mercaptoethanol. They lie the antibbody. But you need to know the site where they lies. Always remember pepine pepine lies at the right. Pepin lies at the hinge region. Pepin lies at the hinge region. Rather than remembering at the hinge region, it is always better to remember above hinge region. It becomes easier for easier for us to understand. Just remember modifying it. Pepin act above the hinge region and pepsin acts below the hinge region. Above the hinge region, below the hinge region. You know at the hinge region if you see there is a dulfide bond. That is important. Okay. What is important is this is important. At the hinge region we have a dulfide bond holding both the heavy chains. Now pepine acts above the hinge region means above this dulfide bond. See here above this dulfide bond and pepsin acts below this dulfide bond. Now you have clearly understood clearly understood that dulfide bond is important. Okay. Pepin acts above the dulfide bond and lies the antibbody. And when pipin lies the antibbody sir you get one FAB fragment, second FAB fragment, one FC fragment.

[00:11:46]The antibbody is liced into three fragments. One FC and two FAB when pepine acts. Simple. Okay. So now coming to the pepsin. When pepsin acts, pepsin acts below the hinge region that is below the dulfide bond. When it acts below the dulfide bond sir here in this in this region there is no dulfide bond.

[00:12:05]As there is no dulfide bond they're not these two heavy chains they're not holding each other they get separated as they get separated we won't call it as a fragment remember to call a part of the antibbody as fragment it must contain dulfide bond therefore we are not cons so so the main problem with the students is they consider this is a fragment but this is not a fragment because there is no dulfide bond this is a fragment because there is a dulfide bond again here what students they get confused is two fab fragments there are two fab FAB fragments but fragments are not two fragment is only one because both the FAB fragments are held each other with this dulfide bond right they are held they are holding each other with this dulfide bond because they're holding each other two FAB fragments are not separated they're they are held each other they're holding each other with this dulfide bond because of this this entire fragment you have to consider as one fragment they're not separated so one fragment containing two fabs you can't say it has two fragments. One fragment containing two fabs. And that's why we write always F A B2.

[00:13:11]One fragment containing two FABS. But here we write two FAB two fragments of FAB and one fragment of FC. Total three fragments. When pepine acts, but when pepsin acts, one fragment of FAB2 and coming to mercaptoanol, mercaptoanol lies, all the dulfide bond. When all the dulfide bonds are lied, heavy chains get separated, light chains get separated.

[00:13:33]we get these are the light chains which got separated. These are the heavy chains which got separated. So now the marking was this is one this is two and this is three. This was the marking and now one is for pepsin one is for pepsin.

[00:13:50]See one pepsin one pepsin one pepsin. So one pepsin means I got a and d options.

[00:13:55]So I will rule out b and c right. Then two is for pepin. So two pepin here. Okay I got the answer a. One is for pepsin. 2 is for pepin. Three is for marapto ethanol. So simple concept is pepine acts above the hinge region.

[00:14:11]Pepsin above the hinge region. Pepsin acts below the hinge region and mercapto ethanol lies the dulfide bond separating heavy chains and light chain. If you know this you can answer this question.

[00:14:20]Option A is the right answer. So next question. So a six-year-old boy presents with fever, headache, central cranial nerve pulses and hydrophilis. Serbos spinal fluid CSF examination shows s low glucose low glucose goes in favor of bacterial elevated protein that is enough to answer to see once you see elevated protein it is always tubercular predominant lymphocytes okay lymphosytes are elevated in tubercular because this chronic bacterial menitis sir this question you can see from central nervous system central nervous system page number 26 so this consists this page consists of ABM adults means acute bacting in adults ABM neonates acute Bactile menitis in CBM chronic bacterial menitis. You know acute bacterial menitis in adults caused by numocco, meningoccus,us, hemoplas, influence, B3 important bacteria and acute bactitis in neonates. Right? Listen to this. We have next question based on neonatal menitis.

[00:15:17]Acute bacterial menitis in units caused by group B steptocus, E.coli and lististeria. Chronic bacterial menitis is caused by mcoact tuberculosis. Total seven important bacteria causing menitis. Three of them acute bacterial menitis in adults, three of them neonatal men acute bactitis in units and one causes chronic bactal menitis. And if you see the CSF analysis picture clearly mentioned here acute bacterial menitis whether it is adults or munates that is just the age group that doesn't matter in acute bacting neutrils increases and glucose decreases. Whereas in chronic bacterial menitis clearly we have written here in chronic bactal menitis sir proteins increases increase in protein always goes in favor of chronic bactal menitis sir clearly they say increased proteins tubercular menitis chronic bacterial menitis caused by mcoact tuberculosis direct question now next question is on neonatal menitis remember which are the factor which causes neonatal menitis grouptoccusol and lististeria right keep this in your brain let's see the question is a six week old infant and presents with features of menitis, neonatal menitis.

[00:16:21]Which of the following combinations of organisms are common causes of menitis in this age group? Common causes of menitis.

[00:16:31]So there are four options. Lististeria, hemophilus, stylocus and streptococcus pneumonia. So streptococcus pneumonia is nothing but pneumocus. Right? First of all, you should not get confused between streptococcus pneumonia and pneumocus both are same. You should you should not consider streptococcus pneumonia and streptococcus. It is pneumocus. So there are four and they're asking most common cause of neonatal menitis to group B streptococcus e.coli Equal listia these are three bacteria grouptoccus is not there ecoli is not there lististeria is there so I my preferred answer is lististeria right now I will see only one right only one option is right sir 1 and 3 1 2 3 4 2 4 1 2 4 if only one option was there I would have gone with only one list is the most common cause of neonatal menitis among the four options as only one is not there then I can see which are the other can cause meniti It is in six week old infant. Sir I will prefer hemophilus because hemophilus usually affects children. Hemophilus usually affects children lower age group then I will include hemophilus also one and two. One and two. Sir option one and two only. If it is there I will go with that option one and two is also not there is also not there. So along with that I have to include one more. If I have to include one more I will include pneumocus. Why? So pneumocus though it causes acute bacterial menitis in adults remember it causes acute bactitetes in elderly also in small children also.

[00:17:56]Numoccus you have to remember it can cause menitis in all age groups.

[00:18:02]It can cause menitis in all age groups but in neonatal it is not most common but it can cause menitis but not most common. It is not under most common but it can cause. So I will go with 1 2 and four. Is that option is there 1 2 and four? Yes sir that option is there 1 2 and four. I will go with the answer 1 to 4. Before I go with 1 to four, there is one more option 1 2 3 4. So three stylocus orius see stylocus orius normally we won't consider as a most common cause of neonatal menitis or even menitis in adults right not though it causes menitis rare not most common cause sir when they're asking most common cause of menitis in neonates I the better answer is only lististeria which is not there if if not listia and hemophilus that is also not there the third better answer is listia hemoplas and streptococcus pneumonia that is there to have gone with answer no need to go with 1 2 3 4 right don't include sephilucus though it can cause rarely that you should not include it but if there is a key point in the question what is the key point a 6 week old infant right admitted in the NI admitted in NICU for past few days prolonged hospital stay is a risk factor for stylocal infection otherwise if they say a 6 week old infant who has undergone neurosurgical procedure no risk factor for stylous a a six week old infant on IV line for long term or risk factor. So we have to say before we answer sephlocus stylocus is hospital acquired and the and the risk factors are neurosurgical procedures IV lines prolonged hospital stay something should be there to answer stphlocus without that you should not answer stephlocus sir if this was the question the better answer is 124 and if this question had a key point like child got admitted in NICU child on IV line for a long time child with neurosurgical who has undergone neurosurgical procedure at in in that case I will go with 1 2 3 four also four also but if this is the question this is the better answer sir with moving to the next question sir a 34 year old women underwent spleentomy spleen see when spleen is removed patient is susceptible for capsulated organisms infection capsulated because capsulated organisms are removed right by spleen and if spleen is not there patient is susceptible high risk of capsulated organism infections and that's why we have to take empirical treatment we have to take empirical treatment treatment if a spleentomy patient manifest with manifest with fever hypotension septic shock and the condition rapidly deteriorates so we have to take the treatment for capsulated organisms and you know most common capsulated organisms are numocockus meningo caucus hemopl which causes menitis and that's why empirical treatment is usually septriak zone septri zone if in or sometimes we add vancomy but usually you need to know spelintomy patient we have to give empirical treatment for capsulated organisms and most common capsulated organisms are numoccuscus hemophilus steeptocus is nothing but pneumocus so what they're asking is which of the following organisms is the target for empirical treatment target for emilical treatment is septoccus pneumonia because it is capsulated.

[00:21:33]Equal microbacttor tuberculosis claustrium deficil they are not targeted they're not going to cause infections usually are most commonly in spleenctomy patient and spleenctomy remol spleen is not related to these three and it won't act as risk factors for this right the answer is stptocous pneumonia so next question sir a 32 year old HIV patient with CD4 count 40 sir HIV patient CD4 count is 40 presents with fever headache and seizures seizures means brain is involved encphilitis is in sephylopathy brain is involved. MRI shows multiple ring enhancing lesions in the basal ganglia. So microbiology questions integrated with radiology. Ring enhancing leion you know is a very important topic in radiology. What is the most likely diagnosis? Sir when you see ring enhancing lesions differential diagnosis in radiology we'll go with cerebral toxopplasmosis and also tuberculoma.

[00:22:29]Sir CNS lymphoma right ring enhancing lesions usually not seen and yes you won't see multiple ring enhancing lesions CNS lymphoma you see one single large uh lesion and progressive multif focal luccoinsphylopathy again it it asymmetrically involves the white matter of the brain you won't see ring enhancing lesions or like that or it won't involve specifically basal ganglia so now there are two possibilities cerebral toxoplasmosis and tuberculoma multiple because We have narrowed down to these two because of the key point multiple ring enhancing lesions are seen in both. Now which one to prefer among these two sir one key point is CD4 and second key point is the side basal ganglia CD4.40 40 and basal ganglia goes in favor of cerebral toxopplasmosis right not preferring tuberculoma again if you see our class notes sir what in the world of revision in the world of revision we have mentioned what is that sir toxopplasmosis toxoplasmosis causes myalgia retinitis and encapitis seizures so we know toxoplasma affect brain causing encphilitis manifest with seizures okay there is the first point seizures are caused by toxoplasma also Second point what you see the opportunistic infection based on the CD4 count.

[00:23:49]Sir usually tuberculosis come when CD4 count is less than 500 and toxopplasma toxoplasmosis when CD4 count is less than 100 or even severe cases of toxoplasmosis when it is less than 50.

[00:24:03]Consider less than 100. So less than 500 goes um tuberculosis is most common.

[00:24:08]Less than 100 toxopplasma is most common. And here the CD4 count is 40. 40 is less than 100 such CD4 count less 40 goes in favor of toxoplasmosis and basal gangliaite which is most commonly involved by toxopplasma because of these two reasons we are going for cerebral toxoplasmosis instead of tuberculoma where also you can see ring enhancing lesions so with that moving on to the next question sir question n elderly women with diabetes militus okay patient is having diabetes militus black necrotic SR over the nose and face characteristic feature of black color lesions and nose and face mucosis. If you see the notes in respiratory system right page number 47 or 48 we have discussed mucar micosis aspergillosis and mucar micosis is discussed side by side where we have written mucar micosis we see black lesions and what is the area rhino cerebral nose and bra. When you see blacker legions on the nose that is the characteristic feature of mucer micosis and we have clearcut return mucar micosis is caused by riseopus absidian mucer and most common riseopus.

[00:25:16]sir when I saw the question black color necrotic on the nose and face mucosis riseopus absidian mucer riseopus got the answer.

[00:25:25]So to say mucor micosis this diabetes millitus right then corticosteroid therapy these are the risk factors and characteristic is sight face black color leion it always mucar micosis if you see the next question a 65 year old patient with uncontrolled uncontrolled diabetes developed severe rhino orbital cerebral mucar micosis previous question they were asking black color lesions on the nose or face what is the diagnosis mucar micosis now they're given the diagnosis mucar micosis and They're asking which of the following drugs is not used in this condition. I have to highlight what they're asking is not used. Not used.

[00:26:03]Again if you go back and see the same slide right in the notes sir we have written aspergyosis treatment is asperillosis.

[00:26:13]Okay. As per gillosis treatment is oriconazole and mucar micosis treatment is lip surgery plus liposomaal amphotary symbian posoconazole right sir oriconazole is for aspergilosis liposomal aoteric symbian posoconazole formucerosis that is what is there in notes sir with that if you see the answer here what is not used with that I can clearly say oriconazole is not used because it is used for aspergilosis. You got the answer and we know we have written liposomaalism B is used. Posonazole is used instead of posonazole. You can also use isonazole but I know oriconazole is not used because it is used for aspergilosis. You got the answer what is not used orazole. So next question seeing the question you should not get right shocked or terrified. What is this such a huge question? Sir in this right vast big questions you have to look for the identify the key points if you have studied well you can identify the key points a 65 year old women with a history of diabetes mitus okay diabetes militus presents with evening evening rise of temperature weight loss and chronic cough so this is a characteristic feature of tuberculosis evening raise of temperature weight loss and chronic cough characteristic feature of tuberculosis she frequently travels to Assam for religious congregation and that history right it I don't see any relevance to tuberculosis let's read the question CT imaging reveals multiple cavitatory lesions multiple cavitatory lesions in the lung and an irregular mass lesion in the liver okay that is possible with tuberculosis multiple cavitatory lesions or mass is possible with tuberculosis laboratory investigation shows elevated ECR ESR and lymphocytosis that is also possible with tuberculosis and they have given the findings biopsy findings reveal okay microbiology question but findings are biopsy biopsy pathology findings biopsy goes to pathology coulative necrosis with langens gene cells goes with tuberculosis necrotic tissue in the liver with granumatus inflammation goes with tuberculosis so the complete question clinical histories of tuberculosis and lab findings pathology lab findings is of tuberculosis but option is not having tuberculosis.

[00:28:43]So with that what I have understood is we have to find out a disease which is right similar to tuberculosis when manifest similar to tuberculosis not only clinically even pathologically it is similar to tuberculosis.

[00:28:55]Again this question is integrated with pathology because they have given the pathology findings. In pathology when we're discussing right this coagulative necrosis, case shiating and non-cashating necrosis you know we always know we always go with right sarcoidosis versus tuberculosis.

[00:29:13]We always goes with saridosis versus tuberculosis. you know in pathology tuberculosis coulative necrosis caseating necrosis but caseating necrosis or cog necrosis is not seen with tuberculosis they're exactly opposite so in this case I will rule out saridosis because it is opposite to tuberculosis you won't see coulative necrosis or necrotic tissue is not seen in saridosis saridosis granomatosis with polyenitis this usually won't involve this characteristic feature this is odd option ruled out asperulosis involves lung. You may see a mass-like leion.

[00:29:50]Cavitatory lesions may also seen but you won't see evening raise of temperature, weight loss, chronic cough but it won't mimic tuberculosis and also you won't see coulative necrosis lang cells in aspergilosis though the possible left out option is hystoplasmosis.

[00:30:05]Such hystopplasmosis is almost similar to tuberculosis not only clinically not only cleven even with the pathological findings like coulative necrosis gran necrotic tissue with granomatus inflammation hystoppplasmosis such option C is odd one out rule out right nothing is going to nothing clinically and lab lab diagnostically nothing is matching with option C asperosis at least you see there is involvement of lung mass like leion cavity lesions are possible but evening raise of temperature weight loss chron is not going in favor of aspergilosis and also necrotic tissue that is also won't go in favor of aspergilosis. So hystoysplasm and sarcoidosis saridosis won't mimic tuberculosis and hystopplasmosis mimic tuberculosis. So you got the answer histoplasmosis conceptual question you had to rule out options you'll get the answer. So next question if you see a patient presents with fever, headache, neck stiffness, neck stiffness means you know diagnosed menitis feature suggest of men they have given menitis. CSF examination is performed nigrosin stain is nothing but negative stain. India ink nigroin these are the negative stains demonstrates bing yeast with unstained hello. Which of the following or this is a very basic question everybody know menitis organism is budding yeast. So you know budding yeast having a hallow hall is nothing but capsule east with a capsule you know cryptocus you know cryptocus is the only capsulated fungus only capsule so you're asking which is the capsulated fungus causing menitis answer is cryptococcus very simple but they're not dealing they're telling directly capsulated birding yeast with unsteined hello in negative state nigroinstein nigroinstein unsteined hello is nothing but capsule you got the answer cryptocus so next question match the following organ mechanisms I always tell students whenever you go with the match the following don't see all the four options first you see the first one H pylori do you know the treatment yes sir H pylori we have triple therapy we have quadruple therapy if you see the notes triple therapy consists of triple therapy quadruple therapy and triple therapy consists of clarithroycin metadoloxic omrazole so here you see clarithroycin is there so one is matching with C where 1 is matching with C 1 C 1 A 1 B 1 D to I rule out B C D I got the answer 1 C only A is the option right so B microagnetosis stptoycin that you know earlier we were using HR z S meanptoin now we use HRZ DPT is removed clidia trachomeatus doxycyc you know clamia tracom we use either ain or doxycyc clamidia trachomatus involve Involving lung aithroyin is preferred.

[00:32:49]Clomidis involving genital area doxicycline is preferred.

[00:32:53]Nonp penicellin is producing gono. Non penicellin is producing gonoko mean sensitive gono cocoa. Amoxiciline can be used but penicellin is producing gonoccone is the drug of choice. So we know even if you don't know all this even if you know one you can see and you can get the answer. Option A is the right answer. So moving on to the next question. Which of the following has two circular DNA segments? This is a bouncer question completely bouncer never asked. I don't think in future they will ask chances of asking in future also very less because circular DNA single stranded double stranded all these things questions from viology that suddenly a bouncer question they have asked vibrio right is having two circular DNA answer is vibrio not only vibrio other than vibrio there are few more bacteria which are having two circular DNA but my what I say is right not needed to remember these things these are bouncer questions once that you know there are many questions which which come once and they never get repeated. This is that kind of question that you have to remember. Vibrio is having two circular DNA. That's why vibro is the answer. Not only vibrio there are few more bacteria but among the options vibrio is having two circular DNA that's why vibro is the answer. So next question sir a 30 a 38 year old man with advanced HIV infection. Okay. CD4 county 60 presents with chronic watery diarrhea.

[00:34:13]Manifestation is watery diarrhea for past two months. significant weight loss, intermittent fever and fatigue.

[00:34:20]Colonoscopy is performed biopsy from the colonic mucosa shown below. This is the biopsy finding. What is the most likely causitive organism for his presentation of the infectious entritis? Okay. The disease is infectious entritis.

[00:34:34]Inflammation of the intestine due to infection watery diarrhea HIV patient.

[00:34:41]Image shows what sir image shows a parasite and they have shown an arrow mark in this arrow mark the pointing towards RBC pointing towards RBC within the parasite RBC containing parasite if you see the nodes the notes clearly mentions RBC is present within antameiba histo parasite containing RBC and we have discussed this clinically so many times in the videos in the notes in the classes that Okay. RBC in the cytoplasm is a characteristic feature of endameibly.

[00:35:15]The answer is endameibly because RBC is present. Sir, if you see the next question, a patient presents with well- definfined scaly plaques over the scalp. Okay, the presentation is scaly plaques over the scalp as shown in the image below. What is the most appropriate treatment? The first you have to diagnose by seeing the image. Such scaly plaques like you see in this image if you see this obviously it goes with fungal infection you have to go with aal antifungals and you know in the notes also we have mentioned what is that sir this is ringworm leion that is the characteristic leion of dermatophyes which is nothing but annular red scaly itchy lesions not only scaly lesions are seen with dermatophyes scaly lesions are seen with many other superficial fungal infections involving the skin squaly lesions is a characteristic features of fungi we'll go with the treatment oral antifungals unless until the image in the exam was right silvery right silvery big patches silvery big patches on the scalp right if there were that's the image had silvery patches right a bigger patches silvery patches then that goes in favor of scalp sorasis at that time in that case we have to go with topical steroids topical steroids but considering this was the image because most of the students said this was the image which was there scaly patches and this image right clinically it is not going towards soriasis to considering it is a scaly plus fungal infection will go with the answer oral antifungal again I'm telling you this answer is completely depends on the image for this image the better answer is oral antifungals next question sir a male patient presents with three old a male presents with 3-day old multiple painful ve I always tell right in my classes even if you seen the videos when you see vicles don't read the question stop there search for herpes virus and answer herpes virus vicles are the characteristic legions of herpes and if you see the past five years question papers wherever herpes examiner expected herpes as an answer right most of the times they give cycles in the question as a examination point of If you see vicles stop there answer herpes more than almost 99 more than 99% of the times you are right sir vesicle lesions and the penis sir vicles the characteristic is herpes this is genital herpes right simple okay sir we have written in the notes we have discussed in the notes if you see sir human herpes viruses characteristic feature is v cycles if you see vycles answer herpes sir identify the wrongly matched pair which is wrongly matched sir Option A cytogalloirus nasoparangial carcinoma.

[00:38:08]Oh god the answer wrongly matched false because hey it is we know everybody knows nasoparangel carcinoma is caused by epstein bar virus. If you see our class nodes epstein bar virus causes infectious monucleiosis two carcinomaomas gastric carcinoma and nasoparangel carcinoma two lymphomas burkits lymphoma and hodkins lymphoma.

[00:38:30]So noperangel cartoon is a characteristic feature of Epstein bar whereas not cytoglas false statement you got the answer then you know HHV8 causes coposoma EBV coposis burkits lymphoma HDLV causes adult T- cell lymphoma you got the answer man very easy so next question why are non-ripimmal tests preferred in cphilis you know if you talk about the diagnosis of syphilis so diagnosis of syphilis first we prefer nontriponymal test why they why they are known as nonriponymal test because Here we are using ox heart antigen not triponal antigen which is the that ox heart antigen we use cardiolipin antigen cardiolipin antigen that's why they're known as nonriponyimal test because we are not using triponal antigens we are using oxalt antigen known as cardiolipin antigen by using this antigen we detect triponymal antibodies because cardolipin antigen is similar to the triponimal antigen As it is similar to triponyimal antigen it can detect triponyimal antibodies.

[00:39:34]So the two important non-trial test what we use are right what we use right are VDRL and RPR VDRL and RPR at the same time we use triponymal test also triponymal test we use triponymal antigensal test we use triponal antigen right triponymal or you can say clearly tryponyma paladum antigen is used and two important tests are FT FTA ABS and TPHA two important tests are FDA AABS and TPHD right so these are the two triponimal test what we use and remember non-triomal tests are used as screening tests screening test and treatment monitoring tests screening test and treatment monitoring tests and tribunimal tests are used as confirmed major tests tribunal test are used as confirmatory test. So these are the test what we use for for the diagnosis of cphilis. Now what they are asking here is sir why non-tripponyimal tests are preferred in cilis.

[00:40:48]See first preferred test are nonriponyimal test. Though we prefer nonriponyal test we have to confirm it by triponymal test but first preferred is nonriponyal. Sir why non-triponimal is preferred that is what they are asking. Okay, let's see the options.

[00:41:02]They have more sensitivity in early stages.

[00:41:06]So this is a true statement. This is a true statement. Remember non-triponyimal tests they have more sensitivity in early stage. You know syphilis is having four stages. Primary cphilis, secondary cphilis, latent cphilis, tertiary cphilis. Nonriponyimal test they have more sensitivity in first two stages and they have less sensitivity in second two stages. That is true statement.

[00:41:28]But that is not why we are preferring a non-trial test. Right? Initially even I thought that is why we prefer because that is what we read in textbooks. They have high sensitive in early stages.

[00:41:36]They high sensitivity in early stages.

[00:41:39]And even I believed in the beginning that is why we prefer for them. But once I compared the sensitivity of non-triponimal test with triponimal test I understood that triponyimal test are also having a good sensitivity like non-triponyimal tests. Triponal test are also having good sensitivity like non-triomal tests. So what they're telling is non-triponal test have good sensitivity in early stages means first two stages. They have poor sensitivity in next two stages. Whereas triponimal test they have almost equal sensitivity like non-triponyimal are more than non-triponyimal and they have good sensitivity in all the four stages. So usually they won't differ in sensitivity. Triponyimal tests are also equally sensitive or better sensitive than non-triponimal test.

[00:42:24]So though this is a true statement they have more see they are comparing in first two stages next two stages for non entrepreneal test if you comp compare first two stages to next two stages non-triminal tests are more sensitivity more sensitive in first two stages but when you compare sensitivity of non-triponyimal test with triponyimal test sensitivity there is no major difference therefore this is not the reason why non-ripolony tests are preferred because even triple test have good sensitivity ivity true statement but that is not why they are preferred to option A is ruled out option A is ruled out this is not not the reason why they are preferred it uses antigen diluted in serum other diluted in serum from other non-specific trunimal test so this statement itself is false because in non-triponimal test we are not using non-specific tryponymal strains we are using cardipin antigen ox heart antigen we are not using triponymal antigen. False statement.

[00:43:25]False statement to false. Right. So next, quantitative results are useful in monitoring the treatment response.

[00:43:33]Quantitative results are useful in monitoring. I told you they are used for treatment monitoring. True statement.

[00:43:39]True statement. Right. So they remain positive independent of recovery from current infection. False.

[00:43:47]They remain positive independent of recovery from. So sir they're asking non-trimal non-trial test remain positive even after recovery. No triponimal test remain positive even after recovery but non-tribal test will become negative after recovery. False statement. So now totally we have two statements here A and B. Two true statements here. Two true statements here A and C. A and C. So among these true statements which is the better reason so that we are preferring non-riponyimal test over triponimal test. Answer is because quantitative results can useful in monitoring the response to therapy because when you compare with the sensitivity even try test have good sensitivity but triponyimal test can't be used for monitoring the treatment response. Why triponimal test can't be used for monitoring the treatment response just now I have given the reason tripimal test once they are positive they remain positive even after recovery when they remain positive for the entire life. How can you monitor after by starting the treatment your treatment is working or not? because they remain positive.

[00:44:47]Whereas non-tripimal test right as the patient gets recovered the antibbody tighter falls and finally after recovery the antibod ttor will disappear. So and because of that reason you can use non-inimal test to monitor the treatment your treatment is working or not. If the titus of antibodies are decreasing on treatment your treatment is working but here titers won't decrease it will remain positive for the whole life.

[00:45:12]So anyways so now we know they have more sensitivity in early stages.

[00:45:15]Non-tripponal test yes non-tribal tests have more sensitivity in early stages but they have almost equal sensitivity compared to triponyimal tests. It uses antigens diluted in serum from other non-specific trunimal stains. No it uses not it won't use non non-specific trunimal strains. It uses cardipin antigen oxide antigen. Quantitative results are useful in monitoring response to therapy. true statement and that is the reason why we prefer non-triponimal test because not only we can use them for the diagnosis we can use them for monitoring the treatment also. So the remain positive and independ uh positive independent of recovery from current infection false tryponyimal test will remain positive.

[00:45:58]Now you can ask me sir then why directly can't use trioneemal test why directly can't use triponimal test for the diagnosis for the diagnosis we won't use triponyimal test directly because uh why we won't use just non-triponimal test why to go for triponimal test because nonriponyimal test have low specificity non-triponimal test have low specificity means they give false positive results that's why we have to confirm by triponimal test even though nontimal test are positive We have to confirm a triponimal test because non-triminal testers have false positivity. Falsely they say positive. That's why we have to confirm a triponimal test. Anyways, we got the answer. Option C is the right answer. So, moving on to the next question. If you see the next question, a 32 year old female presented with a 5-day history of increased vag vaginal discharge means diagnosed vaginitis.

[00:46:49]On speculum examination, the vaginal mucosa was seen to be arythmatus with profuse frothy greenish discharge. Green color discharge means it is parasitic tricomous vaginalis.

[00:47:02]Right? If you see the class notes you can write genital eurogenital system genital system vaginitis. Sir in vagitis we always discuss vaginal discharge is always white in color. If you see colorful discharge yellowish green parasitic tricomus vaginalis.

[00:47:17]Sir key point in this question is green color discharge which goes with tricuminous vaginalis. There are many other key points arithmatis but green is this colorful discharge only one possibility tricomus vaginalis and tirumas vaginalis is contains trophosoid trophosoid is having what it's a trophosoid is having 1 2 3 4 five flagagula a trophosoid with a five flagagula right so that is the answer here right motile flagagillated organism motile flagagillated organism presence of clue cells goes with bacterial vaginosis, gardener vaginalis, gram negative diplocus, meningoccus and gonoccus they won't cause vaginitis sudohhy and spores sudohify is seen with candida pseudoh seen with candida that is fungal vaginitis fungal vaginitis so answer is motile flagagillated organism because tricomus vaginalis is a flagagillated organism having five flagagula with jerky or twitching motility we have discussed many times Jerky twitching motility and here you know it is strainous vision is because of the green color discharge. So moving on to the next question which of the following statements are true about dtheria toxin. So if you talk about dtheria toxin in the notes we have discussed dtheria toxin produced by coronabactin dtheria acts by inhibiting EF2. What is the action? Inhibiting EF2 elongation factor 2. So inhibits EF2 true statement because they're asking true statement regarding diffia toxin and this toxin is having A and B type exotoxin true statement. So this toxin is having two fragments. A fragment B fragment. B is for binding. A is for action. You know AB type of toxins. Two important AB type of toxins. One is anthrax toxin. Second is dtheria toxin.

[00:49:06]Important ones. There are many other also. Right? These toxins have two fragments A and B. With the B fragment the toxin binds. With the A fragment the toxin acts. True statement. It primarily affects myocardium and nerves. Sir Ause C.

[00:49:23]Right? In our notes we have discussed under dtheria. The dtheria affects tonsular area causing pseudo membrane and bull neck lymphopathy. And the very important complication is myocarditis.

[00:49:36]Myocarditis though it is also treatment.

[00:49:39]It primarily affects myocardium and nerves. But not primarily right primarily it affects tonsils. All right.

[00:49:47]So when I see the terminology primarily I have to consider it is a false statement because primarily it affects what tonsils tonsular area. After that as a complication it affects heart and cranial nerves. But here options A and B only is not there. As A and B is not there. I have to go with A B C are the true statement because toxin is produced only by strains carrying plasmid. False statement because this not toxin is not plasmid coded. This toxin is faj coded. Dther toxin is faj coded. You know two types of toxins we have plasmid coded faj coded and dthera toxin is faj coded toxin false statement to a b c are two statement. The answer is a b and c. Right? A b and c. So this is all about the questions which have come from microbiology in INSEAD. And if you see huge number of questions we have almost discussed 22 to 23 questions from microbiology and out of them most of the questions are answerable just from the world of revisions videos which is just 13 hours videos though not all but the strike rate is very good. most of the questions you can answer we have seen and I've showed you the pages from the world of revisions class notes and hope hope you have answered well and hope you have done your exams well and hope you are enjoying microbiology in the with the world of revision along with the world of revision content if you do five years of pqs you can answer all most of the questions in the exams and if by chance if your bad luck if your results have not right gone well with the INSET exam don't worry you have upcoming neat PG exam in just another 3 months and 3 months is a good time to prepare well right along with the world of revision videos right do five years of pqs of neat and nset and better to include right pqs of fmg also and that is going to help to answer all most of the questions from microbiology for sure in your upcoming exams so prepare well prepare smart all the best for your preparation thank