Diseases caused by bacteria Questions in English

(C) Tetanolysin is a cholesterol-binding cytolysin (a type of hemolysin) produced by the bacterium $Clostridium \ tetani$.
It is one of the two major toxins produced by this organism,the other being tetanospasmin,which is responsible for the clinical symptoms of tetanus.

(D) bacterial disease is caused by pathogenic bacteria.
$A$. Measles is a viral disease caused by the measles virus.
$B$. Smallpox is a viral disease caused by the variola virus.
$C$. Rabies is a viral disease caused by the rabies virus.
$D$. Tuberculosis $(TB)$ is a bacterial disease caused by the bacterium $Mycobacterium tuberculosis$.
Therefore, the correct option is $D$.

(D) $Bordetella \ pertussis$ is a Gram-negative,aerobic,pathogenic bacterium that is the causative agent of whooping cough,also known as pertussis.
It primarily affects the respiratory system,leading to severe coughing fits.

(C) Meningitis is an inflammation of the meninges,which are the protective membranes covering the brain and spinal cord.
It can be caused by various pathogens,including viruses,fungi,and bacteria.
Among the options provided,$Neisseria$ $meningitidis$ is a well-known bacterium that causes bacterial meningitis.
Therefore,the correct option is $C$.

(D) Penicillin is a $\beta$-lactam antibiotic that functions by inhibiting the final stage of bacterial cell wall synthesis.
Specifically, it interferes with the cross-linking of peptidoglycan chains, which are essential for the structural integrity of the bacterial cell wall.
By preventing the formation of these cross-links, the cell wall becomes weak, leading to cell lysis and death of the bacterium.

(D) The cell wall of $Mycobacterium$ $tuberculosis$ is characterized by a high concentration of mycolic acids.
These long-chain fatty acids are responsible for the waxy,hydrophobic nature of the cell wall,which contributes to the pathogen's resistance to antibiotics and host immune responses.
Specifically,a glycolipid known as 'cord factor' (trehalose dimycolate) is a major virulence factor found in the cell wall of $Mycobacterium$ $tuberculosis$.

(D) Tuberculin is a protein extract derived from the bacterium $Mycobacterium$ $tuberculosis$. It is classified as an endotoxin because it is a component of the bacterial cell wall that is released upon the death and lysis of the bacterium. It is widely used in the tuberculin skin test to diagnose latent tuberculosis infection.

(B) Tuberculosis $(TB)$ is an infectious disease primarily caused by the bacterium $Mycobacterium$ $tuberculosis$.
It typically affects the lungs but can also impact other parts of the body.
$Shigella$ causes shigellosis, $Salmonella$ causes salmonellosis or typhoid fever, and $TB$ is not caused by a virus.

(C) $Haemophilus$ $influenzae$ is a Gram-negative,coccobacillary,facultatively anaerobic bacterium.
Despite its name,it does not cause influenza (which is a viral disease).
It is a significant human pathogen known to cause various infections,including bacterial meningitis,epiglottitis,pneumonia,and otitis media.

(B) Typhoid fever is a bacterial infection caused by the bacterium $Salmonella$ $\text{typhi}$.
It is transmitted through the ingestion of contaminated food and water.
The pathogen enters the small intestine and migrates to other organs through the blood.
Common symptoms include high fever, weakness, stomach pain, constipation, headache, and loss of appetite.

(A) Plague is an infectious disease caused by the bacterium $Yersinia$ $pestis$ (formerly known as $Pasteurella$ $pestis$).
It is primarily transmitted to humans through the bite of infected fleas that live on small rodents.
Therefore,the correct option is $A$.

(B) Citrus canker is a plant disease that affects citrus species. It is caused by the bacterium $Xanthomonas$ $citri$ (formerly known as $Xanthomonas$ $axonopodis$ $pv.$ $citri$). This pathogen infects the leaves,stems,and fruit of citrus trees,causing characteristic lesions or 'cankers'.

(D) Diphtheria is an infectious disease caused by the bacterium $Corynebacterium$ $diphtheriae$.
It primarily affects the mucous membranes of the throat and nose.
Since $Corynebacterium$ is a prokaryotic organism,it is classified under the kingdom $Monera$ (Bacteria).

(C) Pneumonia is a respiratory disease that affects the alveoli of the lungs.
It is primarily caused by the bacterium $Streptococcus$ $pneumoniae$ (also known as $Diplococcus$ $pneumoniae$) and $Haemophilus$ $influenzae$.
These bacteria infect the alveoli,which are the air-filled sacs of the lungs,causing them to fill with fluid,leading to severe respiratory distress.
Therefore,the correct option is $C$.

(B) Anthrax is an infectious disease caused by the bacterium $Bacillus$ $anthracis$.
It primarily affects animals but can also be transmitted to humans.

(A) $Escherichia \ coli$ is a bacterium that can cause diseases in humans,such as urinary tract infections and food poisoning,particularly when certain pathogenic strains (like $E. \ coli \ O157:H7$) are ingested.
$Xanthomonas \ citri$ causes citrus canker in plants.
$T.M.V.$ (Tobacco Mosaic Virus) is a virus that infects plants.
$Pilobolus$ is a genus of fungi.

(D) $Xanthomonas$ is a genus of bacteria,many species of which are plant pathogens.
$Xanthomonas$ $citri$ is the specific bacterium responsible for causing $Citrus$ canker disease,which is characterized by lesions on the leaves,stems,and fruit of citrus trees.
Therefore,the correct option is $D$.

(C) Leprosy is a chronic infectious disease caused by the bacterium $Mycobacterium \ leprae$. It primarily affects the skin,peripheral nerves,mucosal surfaces of the upper respiratory tract,and the eyes. Therefore,the correct option is $C$.

(A) Bacterial blight of rice is a serious disease caused by the bacterium $Xanthomonas$ $oryzae$ $pv.$ $oryzae$.
This pathogen infects the rice plant through hydathodes or wounds,leading to the development of lesions on the leaves,which eventually turn yellow and white,causing the plant to wither.

(C) $Doxycycline$ is a broad-spectrum tetracycline antibiotic that inhibits bacterial protein synthesis.
$Common$ $cold$ and $Polio$ are viral diseases,and antibiotics are ineffective against viruses.
$Mycoplasma$ are bacteria that lack a cell wall and are susceptible to tetracycline-class antibiotics like $Doxycycline$.
Therefore,male sterility caused by $Mycoplasma$ infection can be treated with $Doxycycline$.

(B) The bacterium $Salmonella$ $typhi$ was discovered in $1880$ by $K.J.$ $Eberth$.
It was later isolated in pure culture in $1884$ by $G.Gaffky$.

(B) $Xenopsylla$ $cheopis$ (Rat flea) is the primary vector for the transmission of $Yersinia$ $pestis$,the bacterium that causes Bubonic Plague. The bacteria multiply within the gut of the flea and are transmitted to humans through the bite of an infected flea.

(C) The housefly ($Musca$ $domestica$) acts as a mechanical vector for various pathogens.
It carries disease-causing microorganisms on its legs and body parts from contaminated surfaces,such as feces or decaying organic matter,to human food and water.
Among the options provided,Typhoid (caused by $Salmonella$ $typhi$) is a classic example of a disease transmitted by houseflies.
Dengue is spread by the $Aedes$ mosquito,and Filariasis is typically spread by the $Culex$ mosquito.

(C) Protein synthesis in bacteria is inhibited by various antibiotics that target the ribosome.
$1$. Erythromycin binds to the $50S$ ribosomal subunit,specifically blocking the exit tunnel of the nascent polypeptide chain,thereby inhibiting protein synthesis.
$2$. Tetracycline and Streptomycin bind to the $30S$ ribosomal subunit.
$3$. Penicillin acts by inhibiting cell wall synthesis,not protein synthesis.
Therefore,the correct answer is Erythromycin.

(A) Bacteria produce harmful substances known as toxins that can cause disease in the host organism.
These toxins are generally classified into two types: exotoxins (secreted by living bacteria) and endotoxins (released upon the death and lysis of the bacteria).
Antitoxins are antibodies that neutralize toxins,while toxoids are inactivated toxins used in vaccines.

(A) $B.C.G.$ stands for $Bacillus$ $Calmette-Guérin$.
It is a vaccine primarily used against $Tuberculosis$ $(T.B.)$,which is caused by the bacterium $Mycobacterium$ $tuberculosis$.
It provides immunity against the disease by introducing a weakened strain of the bacterium into the body.

(A) Antitoxins and toxoids are biological preparations used to provide immunity against specific bacterial toxins.
$Diphtheria$ is a serious bacterial infection caused by $Corynebacterium$ $diphtheriae$,which produces a potent exotoxin.
To prevent this disease,the $Diphtheria$ toxoid (inactivated toxin) is administered as part of the $DPT$ vaccine to stimulate active immunity,or antitoxin serum is given for passive immunity in infected individuals.
Smallpox and chickenpox are viral diseases,and chronic headache is a symptom,not a disease preventable by toxoids.

(A) Tetanus is caused by the bacterium $Clostridium$ $tetani$.
This bacterium produces a potent neurotoxin called tetanospasmin.
This toxin travels to the central nervous system and blocks the release of inhibitory neurotransmitters (like glycine and $GABA$).
As a result,the motor neurons become overactive,leading to continuous,painful spasms and contractions of the voluntary muscles.
Therefore,the toxin primarily affects the voluntary muscles,causing symptoms like lockjaw and muscle rigidity.

(D) The pathogen of bubonic plague is $Yersinia pestis$ (formerly known as $Pasteurella pestis$).
This disease is primarily a zoonotic infection that affects rodents and humans.
The pathogen is transmitted to humans through the bite of the oriental rat flea,$Xenopsylla cheopis$.

(A) $Leprosy$ is a chronic infectious disease caused by the bacterium $Mycobacterium$ $leprae$.
It primarily affects the skin, peripheral nerves, mucosal surfaces of the upper respiratory tract, and the eyes.
Since the causative agent belongs to the genus $Mycobacterium$, option $A$ is the correct answer.

(B) Cholera is an infectious disease caused by the bacterium $Vibrio \text{ } cholerae$.
It primarily spreads through contaminated water or food.

(D) The Widal test is a serological test used for the diagnosis of Typhoid fever.
It detects the presence of agglutinins (antibodies) against the $O$ and $H$ antigens of the bacterium $Salmonella$ $typhi$ in the patient's serum.
This test helps in confirming the infection caused by $Salmonella$ $typhi$.

(A) Tuberculosis $(TB)$ is an infectious disease caused by the bacterium $Mycobacterium$ $tuberculosis$.
It primarily affects the lungs but can also affect other parts of the body.
Therefore, the correct option is $A$.

(C) Diphtheria is an acute infectious disease caused by the bacterium $Corynebacterium$ $diphtheriae$.
It primarily affects the mucous membranes of the nose,throat,or larynx.
The toxin produced by the bacteria leads to the formation of a thick,grey coating in the throat,which can cause difficulty in breathing and swallowing.

(A) Diphtheria is a serious bacterial infection caused by $Corynebacterium$ $diphtheriae$.
It primarily affects the mucous membranes of the throat and nose.
The bacteria produce a toxin that causes a thick,grey coating to form in the back of the throat,which can lead to airway obstruction.
This obstruction results in difficulty breathing and a sensation of suffocation.

(C) Plague is a bacterial disease caused by the pathogen $Yersinia \text{ pestis}$.
It is primarily transmitted to humans through the bite of infected fleas, specifically the rat flea $(Xenopsylla \text{ cheopis})$, which typically lives on rodents like rats.
Therefore, the correct vector for the transmission of plague is the rat flea.

(D) To identify the correct set of bacterial diseases,we must analyze the causative agents for each:
$1$. $A$: Cholera (bacterial),Typhoid (bacterial),Mumps (viral).
$2$. $B$: Tetanus (bacterial),Tuberculosis (bacterial),Measles (viral).
$3$. $C$: Malaria (protozoan),Mumps (viral),Poliomyelitis (viral).
$4$. $D$: Diphtheria (bacterial),Leprosy (bacterial),Plague (bacterial).
Therefore,the set containing only bacterial diseases is Diphtheria,Leprosy,and Plague.

(D) water-borne disease is caused by the ingestion of water contaminated by the excreta of an infected person.
Cholera is a classic example of a water-borne disease caused by the bacterium $Vibrio \text{ } cholerae$.
It spreads primarily through the consumption of contaminated water or food.
Smallpox is a viral disease spread through direct contact or respiratory droplets.
Malaria is a vector-borne disease transmitted by the bite of an infected female $Anopheles$ mosquito.
Tuberculosis is an airborne disease caused by $Mycobacterium \text{ } tuberculosis$.

(D) Tuberculosis $(TB)$ is an infectious disease primarily caused by the bacterium $Mycobacterium$ $tuberculosis$.
This bacterium typically attacks the lungs but can also affect other parts of the body.
It is transmitted through the air when an infected person coughs, sneezes, or talks.
Therefore, the correct causative agent is $Mycobacterium$.

(A) In Ayurveda, the disease known as $Vishuchika$ is identified as Cholera.
$Vishuchika$ is characterized by severe gastrointestinal distress, including vomiting and diarrhea, which are the hallmark symptoms of Cholera caused by the bacterium $Vibrio$ $\text{cholerae}$.

(B) Leprosy, also known as Hansen's disease, is a chronic infectious disease caused by the bacterium $Mycobacterium$ $\text{leprae}$.
It primarily affects the skin, peripheral nerves, mucosal surfaces of the upper respiratory tract, and the eyes.
The clinical symptoms include the loss of skin pigmentation (hypopigmented patches), the formation of scales and ulcers, the wasting of body parts due to nerve damage, and characteristic deformities of the fingers and toes.
Therefore, option $B$ correctly lists the set of symptoms associated with leprosy.

(B) The genus $Mycobacterium$ includes several pathogenic species that cause serious diseases in humans.
$1$. $Mycobacterium$ $tuberculosis$ is the causative agent of Tuberculosis $(T.B.)$.
$2$. $Mycobacterium$ $leprae$ is the causative agent of Leprosy (Hansen's disease).
Therefore,different species of $Mycobacterium$ are responsible for causing $T.B.$ and leprosy.

(D) $Salmonella$ $typhosa$ is the causative agent of typhoid fever.
$1$. It causes an acute infection of the small intestine, leading to sustained high fever ($39^{\circ}C$ to $40^{\circ}C$) and extreme weakness.
$2$. Clinical symptoms include abdominal pain, constipation, and enlargement of the spleen (splenomegaly).
$3$. In severe cases, patients may develop rose-coloured spots (rose spots) on the skin of the trunk.
Therefore, all the given options are correct symptoms associated with typhoid fever.

(B) Leprosy, also known as Hansen's disease, is caused by the bacterium $Mycobacterium \text{ leprae}$.
It is not highly contagious and is not spread through casual contact.
Transmission typically occurs through prolonged, close contact with an untreated infected person, primarily through respiratory droplets from the nose and mouth.

(C) Plague is an infectious disease caused by the bacterium $Yersinia$ $pestis$.
It is primarily transmitted to humans through the bite of infected fleas that live on small rodents.
$Salmonella$ $typhimurium$ causes typhoid fever, $Trichinella$ $spiralis$ causes trichinosis, and $Leishmania$ $donovani$ causes kala-azar (leishmaniasis).
Therefore, the correct option is $C$.

(A) $Yersinia pestis$ is a Gram-negative,non-motile,rod-shaped coccobacillus bacterium.
It is the causative agent of the disease known as Plague.
Plague is a zoonotic disease,typically transmitted to humans through the bite of infected fleas found on rodents.

(A) The term 'Black death' refers to the devastating global epidemic of bubonic plague that struck Europe and Asia in the mid-$14^{th}$ century.
It is caused by the bacterium $Yersinia$ $pestis$,which is primarily transmitted by fleas found on rodents.
The disease is characterized by the formation of dark,necrotic patches on the skin,which led to the name 'Black death'.

(A) The plague is a bacterial disease caused by $Yersinia$ $pestis$ (formerly known as $Bacillus$ $pestis$).
This bacterium is transmitted to humans primarily through the bite of infected fleas.
The specific biological name of the rat flea that acts as the vector for the plague is $Xenopsylla$ $cheopis$.
Therefore,the correct option is $A$.

(B) Koch's postulates are a set of criteria designed to establish a causative relationship between a microbe and a disease.
$1$. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
$2$. The microorganism must be isolated from a diseased organism and grown in pure culture.
$3$. The cultured microorganism should cause disease when introduced into a healthy organism.
$4$. The microorganism must be re-isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
Leprosy, caused by $Mycobacterium$ \text{ leprae}, is an exception because it cannot be grown in a cell-free culture medium (pure culture), which violates the second postulate of Koch.

(A) Diphtheria is a serious infectious disease caused by the bacterium $Corynebacterium$ $diphtheriae$.
It commonly affects the mucous membranes of the nose,throat,and tonsils.
The symptoms include high fever,sore throat,and difficulty in breathing due to the formation of a thick grey coating in the throat.