Bacterial Diseases is part of Biology. Below are notes on 13 sub-topics, followed by practice MCQs from State PSC and UPSC papers.

Anthrax and Plague: Zoonotic bacterial diseases, public health importance

  • Anthrax: Caused by Bacillus anthracis.
  • Bacillus anthracis is the most widely used bioweapon.
  • Anthrax is a bacterial disease of cattle.
  • Plague is a bacterial disease.
  • Both Anthrax and Plague are zoonotic bacterial diseases.
  • Brucellosis: Bacterial disease caused by Brucella abortus.
  • Brucellosis is a reproductive disease of cattle and buffaloes.
  • Brucellosis is a food-borne illness.
  • Haemorrhagic septicaemia: Caused by Pasteurella multocida.
  • Salmonellosis: Caused by Salmonella typhimurium, a food-borne illness.
  • Q fever: Caused by Coxiella burnetii, a foodborne illness.
  • Peptic ulcers are not caused by Bacillus subtilis.
  • Mastitis: Responsible for huge economic losses to the dairy industry.
  • Leprosy: Bacterial disease.
  • Viral diseases mentioned: Mumps, Polio, Rabies, Cow pox, Foot and mouth disease.

Antibiotics: Classification, mechanisms of action, antibiotic resistance

  • Antibiotics are chemical substances (produced by microorganisms or synthesized) that kill or inhibit the growth of bacteria.
  • The term "antibiotic" was coined by Selman Waksman in 1942.
  • Key Discoveries:
    • Penicillin: Discovered by Alexander Fleming in 1928 from the fungus Penicillium notatum.
    • Streptomycin: Discovered by Selman Waksman in 1943 from Streptomyces griseus. Waksman was awarded the Nobel Prize for this discovery.
  • Classification & Mechanisms of Action (MOA):
    • Inhibition of Cell Wall Synthesis: Prevent the formation of peptidoglycan, essential for bacterial cell walls.
      • Examples: Penicillins (e.g., Ampicillin, Amoxicillin), Cephalosporins.
      • Penicillin specifically blocks cell wall formation in bacteria.
    • Inhibition of Protein Synthesis: Target bacterial ribosomes to halt protein production.
      • Examples: Aminoglycosides (e.g., Streptomycin, Gentamicin), Tetracyclines, Macrolides (e.g., Erythromycin).
    • Inhibition of Nucleic Acid Synthesis: Interfere with DNA replication or RNA transcription.
      • Examples: Fluoroquinolones (e.g., Ciprofloxacin), Rifampicin.
    • Inhibition of Metabolic Pathways (Antimetabolites): Block essential metabolic processes (e.g., folic acid synthesis).
      • Examples: Sulfa drugs (Sulfonamides).
      • Sulfa drugs are effective against diseases caused by bacteria.
    • Disruption of Cell Membrane: Damage the bacterial cell membrane, leading to leakage of cellular contents.
      • Examples: Polymyxins.
  • Antibiotic Resistance: The ability of bacteria to survive and multiply in the presence of an antibiotic.
    • Mechanisms of Resistance:
      • Enzymatic Degradation: Bacteria produce enzymes that inactivate the antibiotic.
      • Example: Penicillin resistant bacteria can degrade this antibiotic by an enzyme called βlactamase (also known as penicillinase).
      • Alteration of drug target site.
      • Activation of efflux pumps (pump antibiotic out of cell).
      • Reduced permeability to the antibiotic.
    • Emerging Solutions:
      • Odilorhabdins are a new class of antibiotics discovered to help in fighting drug-resistant or hard-to-treat bacterial infections.

Bacterial Meningitis: Etiology, symptoms, impact

  • Etiology (Causes):
    • Common bacterial agents: Neisseria meningitidis (meningococcus), Streptococcus pneumoniae (pneumococcus), and Haemophilus influenzae type b (Hib).
    • Haemophilus influenzae is a significant cause of meningitis, particularly in young children.
    • Other causes: Group B Streptococcus (Streptococcus agalactiae) in neonates, Listeria monocytogenes in neonates, immunocompromised, and elderly.
  • Symptoms:
    • Classic triad: Fever, severe headache, and stiff neck (nuchal rigidity).
    • Other symptoms: Altered mental status, photophobia (sensitivity to light), phonophobia (sensitivity to sound), nausea, vomiting, seizures, and a non-blanching rash (especially with meningococcal meningitis).
    • In infants: Irritability, poor feeding, lethargy, and a bulging fontanelle.
  • Impact:
    • Life-threatening medical emergency requiring urgent treatment.
    • Can lead to severe neurological sequelae: permanent brain damage, hearing loss, learning disabilities, seizures, and limb loss (in cases of severe septicemia).
    • High mortality rate if left untreated.
    • Preventable through vaccination against Hib, pneumococcus, and meningococcus.

Bacterial Pneumonia: Common causative agents, types, management

  • Pneumonia: Acute inflammatory condition primarily affecting lung alveoli and small airways.
  • Causative Agents: Primarily bacteria (e.g., Streptococcus pneumoniae (most common), Haemophilus influenzae, Staphylococcus aureus, Klebsiella pneumoniae, Mycoplasma pneumoniae (atypical)). Can also be caused by viruses, fungi, or protozoa.
  • Types (Bacterial):
    • Lobar Pneumonia: Affects a large, continuous area of one or more lung lobes.
    • Bronchopneumonia: Characterized by scattered patches of inflammation centered on bronchioles.
  • Special Type (Animals):
    • Drenching Pneumonia (Aspiration Pneumonia): Occurs in animals due to faulty oral administration of liquids (e.g., drugs, feed), leading to their accidental inhalation into the lungs.
  • Management:
    • Diagnosis: Chest X-ray, sputum culture, blood tests.
    • Treatment: Antibiotics (for bacterial pneumonia), supportive care (oxygen therapy, IV fluids, pain relief).
    • Prevention: Vaccination (e.g., pneumococcal vaccine), good hygiene, smoking cessation.

Bacterial sexually transmitted infections (STIs): Syphilis, Gonorrhea

  • Bacterial Sexually Transmitted Infections (STIs)
  • Syphilis
    • Causative Agent: Treponema pallidum (a spirochete bacterium).
    • Transmission: Primarily through sexual contact; also vertically from an infected mother to her fetus (congenital syphilis).
    • Stages: Progresses through primary (chancre), secondary (rash, flu-like symptoms), latent, and tertiary stages (severe organ damage, neurological/ cardiac issues).
    • Treatment: Effectively treated with antibiotics, primarily penicillin.
  • Gonorrhea
    • Causative Agent: Neisseria gonorrhoeae (a Gram-negative coccus bacterium).
    • Discovery: Discovered by Albert Neisser in 1879.
    • Transmission: Primarily through sexual contact; also vertically from an infected mother to her newborn during birth (causing ophthalmia neonatorum).
    • Symptoms: Often asymptomatic; if symptomatic, includes painful urination, abnormal discharge (penile/vaginal). Can lead to pelvic inflammatory disease (PID) in women and epididymitis in men.
    • Treatment: Treated with antibiotics, but drug-resistant strains are a growing concern.

Cholera: Etiology, clinical manifestations, prevention

  • Etiology: Cholera is a bacterial disease caused by Vibrio cholerae.
  • Transmission: Primarily through consumption of food or water contaminated with Vibrio cholerae (fecal-oral route).
  • Clinical Manifestations: Characterized by sudden onset of profuse, watery diarrhea ("rice-water stools"), leading to rapid dehydration and electrolyte imbalance.
  • Prevention: Safe drinking water, proper sanitation and hygiene, food safety practices, and oral cholera vaccines.

Diphtheria: Corynebacterium diphtheriae, toxin, vaccination

  • Diphtheria: An acute, highly contagious bacterial disease.
  • Causative Agent: Corynebacterium diphtheriae (Gram-positive, rod-shaped bacterium).
  • Pathogenesis: The bacterium produces a potent exotoxin (diphtheria toxin).
  • Toxin Action: Interferes with protein synthesis in host cells, leading to tissue damage, particularly in the heart, nerves, and kidneys.
  • Clinical Feature: Formation of a thick, greyish pseudomembrane in the throat and tonsils, which can lead to airway obstruction.
  • Transmission: Primarily via respiratory droplets (coughing, sneezing).
  • Vaccination: Prevented by the DPT (Diphtheria, Pertussis, Tetanus) vaccine.
  • Triple Antigen (DPT): Protects against Diphtheria, Whooping Cough (Pertussis), and Tetanus.

Modes of transmission of bacterial infections

  • Trachoma: Bacterial infection of the eye; India declared free from it.
  • Bacterial diseases include: Diphtheria, Plague, Pneumonia, Whooping Cough, Cystitis.
  • Dengue: Not a bacterial disease (it is viral).
  • Whooping Cough (Pertussis) causative organism: Bordetella pertussis.
  • Ropiness of milk: Caused by bacteria, primary source is air.
  • Coliform bacteria: Found in the human intestine.
  • Milk to curd conversion: Done by Lactobacillus bacteria.
  • Process of milk to curd: Fermentation.
  • Cystitis: Infection of the urinary bladder.

Pathogenesis and virulence factors of bacteria

  • Pathogenic bacteria secrete antigens (e.g., toxins, enzymes) to cause disease.
  • Virulence Factors & Mechanisms:
    • Lipopolysaccharide (LPS): A major component of the cell wall in Gramnegative bacteria, functioning as an endotoxin.
    • Endospores: Produced by Gram-positive, rod-shaped bacteria like Bacillus (e.g., Bacillus species) and Clostridium, aiding survival.
    • Slime layer (Biofilm): Produced by bacteria like Streptococcus mutans from sugar, enabling attachment to surfaces (e.g., teeth, leading to decay).
    • Toxins:
      • Botulinum toxin: Produced by Clostridium botulinum, causing food-borne intoxication (Botulism).
      • Alpha toxin: Produced by Clostridium perfringens.
  • Specific Bacterial Pathogenesis:
    • Helicobacter pylori: Causative agent of peptic ulcers, contributing to hyper acid secretion and infection.
    • Streptococcus mutans: Causes tooth decay by producing a slime layer from sugar, which facilitates attachment to teeth.
    • Clostridium botulinum: Causes Botulism, a food-borne intoxication; a chief contaminant in the canning industry due to anaerobic toxin production.
    • Clostridium perfringens: Produces alpha toxin.
    • Salmonella: Commonly associated with foodborne infections, especially in chicken and eggs.
    • Flexibacter (e.g., Flexibacter columnaris): Causes cotton mouth disease in freshwater fish.
    • Bacterial leaf blight of rice: Characterized by the "Kresek phase" symptom (caused by Xanthomonas oryzae pv. oryzae).
  • Other Relevant Bacterial Information:
    • Lactobacilli: Important in food microbiology; possess a pH optima between
    • Lactobacillus acidophilus: Main organism for producing acidophilus milk, which is prepared from low-fat/ skimmed milk at an optimum temperature of 37 °C.
    • Leuconostoc: Involved in sauerkraut fermentation; its growth can be inhibited by excessively high temperatures.
    • Bacteriophage: A type of virus that infects and replicates within bacteria, leading to bacterial lysis; does not stimulate bacterial growth.

Prevention and control of bacterial diseases: Vaccination, sanitation, public health strategies

  • Vaccination: Induces active immunity against specific bacterial diseases (e.g., DPT for Diphtheria, Pertussis, Tetanus; BCG for Tuberculosis; Typhoid vaccine).
  • Antibiotics: Medications that kill or inhibit bacterial growth. Agrimycin is an antibiotic used to control bacterial diseases.
  • Sanitation:
    • Water Disinfection: Methods include boiling, chlorination, filtration. For UV disinfection, water is allowed to pass in thickness not exceeding 12 cm.
    • Waste Management: Proper disposal of sewage and solid waste.
    • Personal Hygiene: Handwashing, food safety, regular bathing.
  • Antiseptics & Disinfectants: Chemical agents used to kill or inhibit bacteria.
    • Antiseptics (e.g., Betadine) are applied to living tissues. Betadine is an antibacterial solution containing Iodine.
    • Disinfectants (e.g., Formaldehyde, Hydrogen Peroxide, Alcohol) are used on inanimate objects.
  • Public Health Strategies: Surveillance, early diagnosis and treatment, isolation/quarantine, health education, improving living conditions, vector control.

Tetanus: Clostridium tetani, neurotoxin, immunization

  • Causative Agent: Clostridium tetani (a bacterium).
  • Key Pathogenic Factor: Produces potent neurotoxins, primarily tetanospasmin.
  • Mechanism: Neurotoxins block release of inhibitory neurotransmitters, leading to spastic paralysis (sustained muscle contractions).
  • Transmission: Spores of Clostridium tetani enter the body through puncture wounds contaminated with soil, dust, or animal feces.
  • Immunization: Prevented by vaccination with Tetanus Toxoid, often administered as part of DPT (Diphtheria, Pertussis, Tetanus) or DTaP vaccine.

Tuberculosis: Causative agent, symptoms, diagnosis, treatment

  • Causative Agent: Mycobacterium tuberculosis (a bacterium).
  • Classification: Bacterial disease.
  • Transmission: Airborne/Droplet infection (coughing, sneezing) from an infected person. Risk increases in crowded places.
  • Symptoms: Primarily affects lungs (pulmonary TB), but can affect other organs (extrapulmonary TB). Common symptoms include chronic cough with blood-tinged sputum, fever, night sweats, and weight loss.
  • Prevention: BCG (Bacille Calmette-Guérin) vaccine.
  • Treatment: Multi-Drug Therapy (MDT) involving a combination of antibiotics.

Typhoid Fever: Salmonella Typhi infection, symptoms, control

  • Typhoid fever is a bacterial disease.
  • It is caused by the bacterium Salmonella typhi.
  • Transmission occurs via contaminated food and water (feco-oral route).
  • The infection primarily affects the small intestine and can spread to other organs.
  • Symptoms: Sustained high fever (39°C to 40°C), headache, weakness, stomach pain, constipation or diarrhea, loss of appetite. Rose spots on the skin may also appear. Severe cases can lead to intestinal perforation.
  • The Widal test is used for the confirmation of typhoid fever.
  • Control/Prevention: Ensuring proper sanitation, access to safe drinking water, maintaining personal hygiene, and vaccination.

26. Fungal Diseases

Practice MCQs: Bacterial Diseases

Anthrax and Plague: Zoonotic bacterial diseases, public health importance

  1. Most widely used bioweapon is

    Asked in: TNPSC CS Prelims 2019

    1. Bacillus subtilis
    2. Vibrio cholerae
    3. Bacillus anthracis
    4. Escherichia coli
    Show answer

    Answer: C. Bacillus anthracis

    Biological weapons utilize living organisms or toxins derived from them to cause disease or death.

  2. Disease responsible for huge economic losses to dairy industry every year is

    Asked in: Agri. Officer 2020

    1. Metritis
    2. Milk fever
    3. Mastitis
    4. Teat block
    Show answer

    Answer: C. Mastitis

    Mastitis is the most economically damaging disease to the dairy industry due to its impact on milk production and animal health.

  3. Causative agent of haemorrhagic septicaemia is ______.

    Asked in: RO ARO pre 2016 · Food Safety Officer 2019

    1. Pasteurella multocida
    2. Clostridium chauvoei
    3. Brucella abortus
    4. Mycobactérium bovis
    Show answer

    Answer: A. Pasteurella multocida

    RO ARO pre -2016 H₅N₁ is the specific strain of the influenza virus responsible for Bird Flu. Ans: A Haemorrhagic septicaemia is characterized by sudden onset, fever, respiratory distress, and often subcutaneous edema, with a high mortality rate. It is a significant disease in livestock management.

  4. The incorrect pair of food borne illness and its causative microorganism is :

    Asked in: Food Safety Officer 2022

    1. Brucellosis – B. abortus
    2. Peptic ulcers – B. subtilis
    3. Salmonellosis – S. typhimurium
    4. Q fever – C. burnetti
    Show answer

    Answer: B. Peptic ulcers – B. subtilis

    The causative agent of peptic ulcers is Helicobacter pylori. Bacillus subtilis is not associated with causing peptic ulcers.

  5. Which statement is correct about Brucellosis in cattle and Buffaloes ? - It is a reproductive disease of cattle and Buffaloes. - It is a metabolic disease of cattle and Buffaloes. - It is a viral disease of cattle and Buffaloes. - It is a skin disease of cattle and buffaloes.

    Asked in: Food Safety Officer 2022

    1. (1) only
    2. (2) and (3) only
    3. (1) and (4) only
    4. (1), (2) and (3) only
    Show answer

    Answer: A. (1) only

    Brucellosis is a bacterial disease primarily affecting the reproductive system of cattle and buffaloes, leading to reproductive issues.

  6. Which of the following diseases are / is caused by bacteria? 1) Leprosy 2) Plague 3) Mumps 4) Polio Select the correct answer using the code given below : Code :

    Asked in: Civil Judge 2018

    1. 1 and 3 are correct
    2. 1 and 2 are correct
    3. 1, 3 and 4 are correct
    4. All are correct
    Show answer

    Answer: B. 1 and 2 are correct

    This question requires knowledge of the causative agents of common diseases, specifically differentiating between bacterial and viral infections. Accurate identification of which diseases are bacterial is key to selecting the correct option.

  7. "Brucellosis" is a disease caused by -

    Asked in: Civil Judge 2022

    1. Virus
    2. Bacteria
    3. Protozoa
    4. Fungus
    Show answer

    Answer: B. Bacteria

    Viruses cause diseases like influenza and COV‐ ID-19. Protozoa cause diseases like malaria. Fungi cause diseases like athlete's foot.

Antibiotics: Classification, mechanisms of action, antibiotic resistance

  1. Antibiotic such as penicillin blocks

    Asked in: UPSC CDS 2 2020

    1. cell wall formation in bacteria
    2. RNA synthesis in bacteria
    3. DNA synthesis in bacteria
    4. division in bacteria
    Show answer

    Answer: A. cell wall formation in bacteria

    Penicillin inhibits the transpeptidase enzymes (also known as penicillin-binding proteins or PBPs) that cross-link the peptidoglycan chains, which are essential for the structural integrity of the bacterial cell wall. This weakens the wall, leading to cell lysis (bursting) due to osmotic pressure.

  2. Which one of the following statements regarding Penicillin is correct ?

    Asked in: UPSC NDA 1 2019

    1. Penicillin resistant bacteria can store this antibiotic in vacuole
    2. Penicillin resistant bacteria can degrade this antibiotic by an enzyme called β-lactamase
    3. Penicillin resistant bacteria can degrade this antibiotic by an enzyme called lactic acid dehyd‐ rogenase
    4. Penicillin is not absorbed by bacteria, so most bacteria are resistant
    Show answer

    Answer: B. Penicillin resistant bacteria can degrade this antibiotic by an enzyme called β-lactamase

    Beta-lactamase enzymes break the beta-lactam ring structure, which is essential for the activity of penicillin and related antibiotics.

  3. The term antibiotic was coined by

    Asked in: UKPSC CS Prelims 2024

    1. Davie and Ratnoff
    2. Edward O. Wilson
    3. M. Pearl
    4. Selman Waksman
    Show answer

    Answer: D. Selman Waksman

    Selman Abraham Waksman was a Ukrainian-born Jewish-American inventor, biochemist, and microbiologist. He coined the term "antibiotic" in 1942 to describe substances produced by microorganisms that inhibit the growth of other microorganisms. His laboratory discovered streptomycin in 1943, which was the first antibiotic effective against tuberculosis. For his pioneering work on antibiotics, Waksman was awarded the Nobel Prize in Physiology or Medicine in 1952.

  4. Sulpha drugs are effective against diseases caused by:

    Asked in: RPSC RAS Prelims 1996

    1. Bacteria
    2. Worms
    3. Vitamin Deficiency
    4. Glandular upsets
    Show answer

    Answer: A. Bacteria

    Sulfa drugs, or sulfonamides, were the first class of antimicrobial drugs used to treat bacterial infections. They work by inhibiting the synthesis of folic acid, which is essential for bacterial growth.

  5. What is the name of antibiotics that has been discovered to help in fighting drug resistant or hard-to-treat bacterial infections?

    Asked in: WBCS Main Paper 4 2023

    1. Philo habdins
    2. Odilor habdins
    3. Oli habdins
    4. Ozor habdins
    Show answer

    Answer: B. Odilor habdins

    Odilorhabdins (ODLs) are a novel class of antibiotics discovered in 2018. They are produced by symbiotic bacteria (Photorhabdus and Xenorhabdus) that live inside soil-dwelling nematodes. These antibiotics target the ribosome of bacteria at a site not used by current antibiotics, making them effective against many drug-resistant strains.

  6. Penicillin was discovered by : (b) Waldeyer Fleming (c) Alexander Fleming (d) Robert Hooke

    Asked in: ukpsc 2025 2025

    1. E.J. Butler
    2. Waldeyer Fleming
    3. Alexander Fleming
    4. Robert Hooke
    Show answer

    Answer: C. Alexander Fleming

    Alexander Fleming discovered Penicillin.

  7. Waksmann was awarded Noble Prize for the discovery of :

    Asked in: Paper I 4

    1. Streptomycin
    2. Neomycin
    3. Pencillin
    4. Chloromycetin
    Show answer

    Answer: A. Streptomycin

    The Nobel Prize in Physiology or Medicine was awarded to Selman Waksman for the discovery of streptomycin.

Bacterial Meningitis: Etiology, symptoms, impact

  1. The bacillus heamophilus influenza causes

    Asked in: UPPCS Prelims 2022

    1. Whooping cough
    2. A form of meningitis in young children
    3. Pneumonia
    4. Influenza
    Show answer

    Answer: B. A form of meningitis in young children

    Haemophilus influenzae, particularly the type b strain (Hib), is a major cause of bacterial meningitis in young children.

Bacterial Pneumonia: Common causative agents, types, management

  1. The pathogen of pneumonia is

    Asked in: Clerk GR II Comb. Comp. Exam 2013

    1. Bacteria
    2. Fungi
    3. Protozoa
    4. Virus
    Show answer

    Answer: A. Bacteria

    Pneumonia is most frequently caused by bacteria.

  2. Pneumonia in animals occurs due to faulty administration of drugs is ____.

    Asked in: Food Safety Officer 2019

    1. Interstitial pneumonia
    2. Gangrenous pneumonia
    3. Parasitic pneumonia
    4. Drenching pneumonia
    Show answer

    Answer: D. Drenching pneumonia

    Faulty administration of drugs, particularly during drenching, can lead to inhalation of the liquid into the lungs, causing drenching pneumonia.

Bacterial sexually transmitted infections (STIs): Syphilis, Gonorrhea

  1. Neisser in 1879 discovered a sexually transmitted disease known as

    Asked in: TNPSC CS Prelims 2014

    1. Syphillis
    2. AIDS
    3. Gonorrhoea
    4. Hydrocele
    Show answer

    Answer: C. Gonorrhoea

    - Albert Neisser discovered Neisseria gonorrhoeae, the causative agent of gonorrhoea. - His discovery was made in 1879.

Cholera: Etiology, clinical manifestations, prevention

  1. Which one of the following statements regarding Cholera is correct ?

    Asked in: UPSC NDA 1 2019

    1. Cholera is a disease that causes loss of memory
    2. Cholera is a disease of muscles due to consumption of alcohol
    3. Cholera is a disease due to consumption of contaminated food or water
    4. Cholera is a genetic disease
    Show answer

    Answer: C. Cholera is a disease due to consumption of contaminated food or water

    Cholera is caused by the bacterium Vibrio cholerae, which is transmitted through the fecal-oral route.

  2. Which one among the following waterborne diseases is not caused by bacteria?

    Asked in: ASCO 2014

    1. Cholera
    2. Typhoid
    3. Bacillary dysentery
    4. Hepatitis A
    Show answer

    Answer: D. Hepatitis A

    It is important to distinguish between bacterial and viral causes of waterborne diseases for appropriate treatment and prevention.

Diphtheria: Corynebacterium diphtheriae, toxin, vaccination

  1. Triple antigen is given to a child to prevent :

    Asked in: UPPCS Prelims 1994

    1. Polio,smallpox,diphtheria
    2. Diphtheria whooping cough, tetanus
    3. Smallpox, whooping cough, tetanus
    4. Polio, tetanus, whooping cough.
    Show answer

    Answer: B. Diphtheria whooping cough, tetanus

    The Triple Antigen vaccine, commonly known as DPT, protects against Diphtheria, Pertussis (Whooping Cough), and Tetanus. It is a crucial part of childhood immunization programs worldwide.

Modes of transmission of bacterial infections

  1. India is declared free from trachoma which takes place due to infection of ________ in the eye.

    Asked in: GPSC Prelims CSP 2 2021

    1. Virus
    2. Fungi
    3. Bacteria
    4. None of the above
    Show answer

    Answer: C. Bacteria

    Trachoma is a neglected tropical disease caused by infection with the bacterium Chlamydia trachomatis. Repeated infections can cause scarring of the eyelid, leading to the eyelashes turning inwards and scratching the cornea, which can result in irreversible blindness.

  2. Which one of the following diseases is not a bacterial disease ?

    Asked in: RPSC RAS Prelims 2023

    1. Diphtheria
    2. Plague
    3. Pneumonia
    4. Dengue
    Show answer

    Answer: D. Dengue

    Diseases can be caused by various pathogens including bacteria, viruses, fungi, and parasites.

  3. The causative organism of Whooping Cough

    Asked in: TNPSC CS Prelims 2024

    1. Bordetella pertussis
    2. Diphtheria antitoxin
    3. Streptococcal pneumonia
    4. Salmonella paratyphi
    Show answer

    Answer: A. Bordetella pertussis

    Whooping cough, also known as pertussis, is a highly contagious respiratory disease. It is caused by the bacterium Bordetella pertussis.

  4. The primary source of bacteria causing ropiness of milk is :

    Asked in: Food Safety Officer 2022

    1. Air
    2. Water
    3. Utensil
    4. Animal
    Show answer

    Answer: D. Animal

    Ropiness in milk is a spoilage defect caused by the excessive production of exopolysaccharides (EPS) by certain bacteria, which gives the milk a viscous or "ropy" texture. Common culprits include species of Bacillus and Lactococcus. The most direct and often primary source for these bacteria to enter the milk supply is through contamination from the infected udder of the animal.

  5. Coliform bacteria are found in which human organ?

    Asked in: School Lecturer (School Edu.) 2018 3 2018

    1. Heart
    2. Intestine
    3. Kidney
    4. Liver
    Show answer

    Answer: B. Intestine

    Coliform bacteria are indicators of fecal contamination. Their natural environment is the gastrointestinal tract of mammals.

  6. By which of the following bacteria can milk change into curd?

    Asked in: Additional Private Secretary Exam 2017

    1. Azotobacter
    2. Penicillium
    3. Lactobacillus
    4. Nitrobacter
    Show answer

    Answer: C. Lactobacillus

    Lactobacillus bacteria are responsible for the lactic acid fermentation process that turns milk into curd.

  7. In curd, which bacteria are found in abundance ?

    Asked in: Assistant Conservator of Forest Exam 2019

    1. Salmonella sps.
    2. Lactobacillus sps.
    3. E. coli
    4. All of these
    Show answer

    Answer: B. Lactobacillus sps.

    Lactic acid bacteria, particularly species of Lactobacillus, are primarily responsible for the fermentation process that converts milk into curd (yogurt). These bacteria produce lactic acid, which causes the milk proteins to coagulate and gives curd its characteristic sour taste and texture.

Pathogenesis and virulence factors of bacteria

  1. Apart from hyper acid secretion, peptic ulcers are also developed due to bacterial infection. The causative agent is

    Asked in: UPSC CDS 2 2020

    1. Helicobacter pylori
    2. E. coli
    3. Streptococcus pneumoniae
    4. Salmonella typhimurium
    Show answer

    Answer: A. Helicobacter pylori

    For a long time, peptic ulcers (ulcers in the lining of the stomach or duodenum) were primarily attributed to lifestyle factors like stress and diet leading to excessive acid production. However, research by Barry Marshall and Robin Warren in the 1980s revolutionized the understanding of peptic ulcers by demonstrating that the bacterium Helicobacter pylori is a major cause. This bacterium can survive in the acidic environment of the stomach and colonize the gastric lining, causing inflammation and making the tissue vulnerable to acid damage, leading to ulcer formation.

  2. An important cause of tooth decay by the bacterium Streptococcus mutans is because of their ability to attach to teeth surface by producing slime layer from

    Asked in: UPSC NDA 2 2023

    1. Sugar
    2. Alcohol
    3. Saliva
    4. Teichoic acid
    Show answer

    Answer: A. Sugar

    Streptococcus mutans is a key bacterium in the initiation of dental caries (tooth decay). It produces both acid and a sticky matrix from fermentable carbohydrates, primarily sugars.

  3. Botulism is

    Asked in: UPPCS Prelims 2021

    1. Food-borne infection
    2. Food-borne intoxication
    3. Water-borne infection
    4. Water-borne intoxication
    Show answer

    Answer: B. Food-borne intoxication

    Botulism is primarily caused by consuming toxins produced by Clostridium botulinum, making it a food-borne intoxication.

  4. The bacteria which causes peptic ulcer —

    Asked in: WBCS Main Paper 4 2021

    1. Lactobacillus acidophilus
    2. Helicobacter pylori
    3. Peptostreptococcus
    4. Streptococcus avium
    Show answer

    Answer: B. Helicobacter pylori

    Helicobacter pylori is the primary bacterial cause of peptic ulcers. NSAID use is another major cause.

  5. Kresek phase symptom found in plant disease

    Asked in: Agri. Officer 2020

    1. Late blight of potato
    2. Black arm of cotton
    3. Bacterial leaf blight of rice
    4. Leaf curl of chilli
    Show answer

    Answer: C. Bacterial leaf blight of rice

    Kresek phase is a typical symptom of Bacterial leaf blight of rice.

  6. In freshwater fish, cotton mouth disease is caused due to - Question not attempted

    Asked in: Asst. Fisheries Development Officer 2024

    1. Myxobacteria
    2. Mycobacteria
    3. Flexibacteria
    4. Chondrococcus
    Show answer

    Answer: A. Myxobacteria

    Cotton mouth disease in freshwater fish is caused by Myxobacteria.

  7. The bacteria that are commonly associated with foodborne infections in chicken or eggs are : (1) Salmonella (2) Bacillus (3) Staphylococcus (4) Clostridium (5) Question not attempted

    Asked in: Deputy Jailor 2024

    1. Option text
    2. Option text
    3. Option text
    4. Option text
    Show answer

    Answer: A. Option text

    Salmonella bacteria are commonly associated with foodborne infections in chicken or eggs.

Prevention and control of bacterial diseases: Vaccination, sanitation, public health strategies

  1. 'Agrimycin' is used to control which of the following diseases ?

    Asked in: MPSC CS Prelims 2015

    1. Fungal diseases
    2. Viral diseases
    3. Bacterial diseases
    4. Mycoplasma diseases
    Show answer

    Answer: C. Bacterial diseases

    Agrimycin is an antibiotic mixture used to control bacterial diseases in plants.

  2. Ultra-violet rays are highly disinfectants and kill the disease bacteria, in this disinfection method water is allowed to pass in thickness not exceeding ______ before the ultraviolet rays.

    Asked in: Local Self Government Dept. Exam 2022

    1. 8 cm
    2. 15 cm
    3. 12 cm
    4. 10 cm
    Show answer

    Answer: A. 8 cm

    - UV Disinfection Ultraviolet (UV) disinfection is a method used to inactivate pathogenic microorganisms in water by exposing them to UV light. - Water Thickness The effectiveness of UV disinfection is dependent on the depth of water the UV rays need to penetrate. A thinner layer allows for maximum UV exposure. - Standard Thickness The commonly accepted maximum thickness of water for effective UV disinfection is 8 cm (approximately 3 inches).

  3. Betadine is an antibacterial solution containing :-

    Asked in: Assistant Engineer (AE) Exam 2013

    1. Formaldehyde
    2. Hydrogen Peroxide
    3. Iiodine
    4. Alcohol
    Show answer

    Answer: C. Iiodine

    Povidone-iodine, the active ingredient in Betadine, is a broad-spectrum antiseptic that kills bacteria, viruses, fungi, and protozoa.

Tetanus: Clostridium tetani, neurotoxin, immunization

  1. Tetanus is caused by :-

    Asked in: Assistant Engineer (AE) Exam 2013

    1. Bacteria
    2. Virus
    3. Fungi
    4. Protozoa
    Show answer

    Answer: A. Bacteria

    Tetanus is a serious infection caused by toxins produced by the bacterium Clostridium tetani. The bacteria are commonly found in soil, dust, and manure.

Tuberculosis: Causative agent, symptoms, diagnosis, treatment

  1. Statement I : A person may suffer from tuberculosis if she/he frequently visits crowded place. Statement II : Bacteria of tuberculosis spread through droplets by sneezing or coughing.

    Asked in: UPSC CDS 1 2018

    1. Option text is missing in the image.
    2. Option text is missing in the image.
    3. Option text is missing in the image.
    4. Option text is missing in the image.
    Show answer

    Answer: A. Option text is missing in the image.

    Tuberculosis is an airborne infectious disease. Transmission occurs through inhaling infectious droplets.

  2. The cause of Tuberculosis is

    Asked in: CGPSC Prelims Exam 2012

    1. virus
    2. bacteria
    3. fungi
    4. protozoan
    Show answer

    Answer: B. bacteria

    TB is an infectious disease that usually affects the lungs but can also affect other parts of the body. It spreads through the air when a person with active TB coughs, sneezes, or talks.

  3. Which of the following diseases is caused by bacteria ?

    Asked in: UPPSC Upper Mains 2010

    1. Athlete's toot
    2. Tuberculosis
    3. Ringworm
    4. Thrush
    Show answer

    Answer: B. Tuberculosis

    Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. It typically affects the lungs but can also affect other parts of the body. Athlete's foot, ringworm, and thrush are all fungal infections.

  4. Which of the following is not caused by bacteria?

    Asked in: Civil Judge 2018

    1. Malaria
    2. Typhoid
    3. Diphtheria
    4. Tetanus
    Show answer

    Answer: A. Malaria

    Identifying the causative agent (bacteria, virus, protozoa, fungi) of common diseases is essential for answering this question. - Malaria: Protozoan (Plasmodium) - Typhoid: Bacteria (Salmonella Typhi) - Diphtheria: Bacteria (Corynebacterium diphtheriae) - Tetanus: Bacteria (Clostridium tetani)

  5. BCG Vaccine is used against which of the following diseases ?

    Asked in: Chief Fire Officer Exam 2021

    1. T.B. (Tuberculosis)
    2. Cholera
    3. Hepatitis
    4. Bird flu
    Show answer

    Answer: A. T.B. (Tuberculosis)

    BCG vaccine is administered to protect against Tuberculosis.

  6. Tuberculosis disease is caused by

    Asked in: Economics & Statistical Officer Exam 2005

    1. Virus
    2. Bacteria
    3. Protozoa
    4. Fungi
    Show answer

    Answer: B. Bacteria

    This bacterium typically attacks the lungs but can also damage other parts of the body. It spreads through the air when a person with active TB coughs, sneezes, or spits.

  7. BCG is used to prevent

    Asked in: Sub Inspector 2021

    1. hydrophobia
    2. cancer
    3. neuralgia
    4. tuberculosis
    Show answer

    Answer: D. tuberculosis

    The question asks about the disease that the BCG vaccine is used to prevent. This is a fundamental concept in public health and immunization.

Typhoid Fever: Salmonella Typhi infection, symptoms, control

  1. Which one of the following is caused by a bacterial pathogen?

    Asked in: UPSC NDA 1 2022

    1. AIDS
    2. Dengue fever
    3. COVID-19
    4. Typhoid fever
    Show answer

    Answer: D. Typhoid fever

    Pathogens can be viruses, bacteria, fungi, or parasites. It is important to know the type of pathogen causing common diseases.

  2. Which one of the following is a bacterium that causes disease in the human body ?

    Asked in: UPSC NDA 2 2019

    1. Varicella zoster
    2. Trypanosoma gambiense
    3. Salmonella typhi
    4. Plasmodium falciparum
    Show answer

    Answer: C. Salmonella typhi

    The question asks to identify a bacterium from the given options that causes disease in humans.

  3. Which test is used for confirmation of typhoid fever?

    Asked in: Junior Accountant and TRA 2013

    1. Coomb’s test
    2. Widal test
    3. Mantoux test
    4. Kastle-Meyer test
    Show answer

    Answer: B. Widal test

    The Widal test is a standard diagnostic tool for typhoid fever.