Infectious Diseases

Infectious Diseases Indian Medical PG Question 1: Zoonotic diseases are -

• A. Anthrax
• B. Plague
• C. Salmonellosis
• D. All of the options (Correct Answer)

Infectious Diseases Explanation: ***All of the options*** - **Anthrax**, **Plague**, and **Salmonellosis** are all well-established examples of zoonotic diseases, which are infections naturally transmitted between vertebrate animals and humans. - These diseases represent a diverse spectrum of bacterial infections with significant public health implications worldwide. **Anthrax** - Caused by *Bacillus anthracis*, a spore-forming bacterium naturally found in soil that primarily affects livestock and wild herbivores. - Humans acquire infection through contact with infected animals or contaminated animal products (hides, wool, meat). - Clinical forms include cutaneous (most common), inhalational (most severe), and gastrointestinal anthrax. - Remains an important occupational hazard for veterinarians, farmers, and those handling animal products. **Plague** - Caused by *Yersinia pestis*, maintained in nature through rodent-flea cycles. - Transmission to humans occurs primarily via bites from infected fleas or direct contact with infected animals. - Historically responsible for devastating pandemics including the Black Death. - Clinical manifestations include bubonic (most common), pneumonic (person-to-person transmission possible), and septicemic plague. **Salmonellosis** - Caused by non-typhoidal *Salmonella* species, commonly colonizing the intestines of various animals including poultry, cattle, reptiles, and pets. - Humans typically acquire infection through consumption of contaminated food (undercooked meat, eggs, unpasteurized dairy) or direct animal contact. - Presents as acute gastroenteritis with diarrhea, fever, and abdominal cramps. - One of the most common foodborne zoonotic infections globally.

Infectious Diseases Indian Medical PG Question 2: Consider the following characteristics of biological agents : 1. Infectivity 2. Pathogenicity 3. Virulence 4. Communicability Among the above characteristics, which are used to measure the ability of biological agents to induce clinically apparent illness?

• A. 3 only
• B. 2 and 3 (Correct Answer)
• C. 2 only
• D. 1 and 2

Infectious Diseases Explanation: ***2 and 3*** - **Pathogenicity** is the ability of an infectious agent to cause disease (clinically apparent illness) in infected individuals, measured as the proportion of infected persons who develop clinical disease. - **Virulence** is the ability of an agent to produce severe disease, measured as the proportion of clinical cases that are severe or fatal. - **Both characteristics measure different aspects of the ability to induce clinically apparent illness**: pathogenicity measures whether clinical illness occurs, while virulence measures the severity of that clinical illness. - Together, they comprehensively describe an agent's capacity to produce clinically apparent disease. *2 only* - While pathogenicity does measure the ability to cause clinically apparent illness, this is incomplete. - Virulence is also a measure of the ability to induce clinically apparent illness, specifically measuring the severity spectrum of that illness. *3 only* - Virulence alone is insufficient as it only measures severity among those who are already clinically ill. - Pathogenicity is also needed to measure the ability to produce clinical illness in the first place. *1 and 2* - **Infectivity** measures the ability of an agent to enter, survive, and multiply in a host, which is a prerequisite for disease but does not measure clinical illness itself. - An agent can have high infectivity but low pathogenicity (causing mostly subclinical infections). - Only pathogenicity and virulence directly measure aspects of clinically apparent illness.

Infectious Diseases Indian Medical PG Question 3: A 30-year-old male presents with chills and a high fever of 40°C. Which of the following symptoms would most likely suggest an infectious cause?

• A. Rigors (Correct Answer)
• B. Excessive sweating
• C. Skin rash
• D. Vomiting

Infectious Diseases Explanation: ***Rigors*** - **Rigors** (generalized shivering with a sensation of cold) are strong indicators of a rapid and significant rise in body temperature, often seen with **bacteremia** or other severe infections [1]. - The body's defense mechanisms are fighting off a severe infection, leading to an exaggerated physiological response. *Excessive sweating* - **Excessive sweating (diaphoresis)** typically occurs as the body attempts to cool down during the defervescence (fever reduction) phase [1]. - While associated with fever, it is less specific for the *onset* or active phase of an infection compared to rigors [1]. *Skin rash* - A **skin rash** can be a symptom of certain infections (e.g., viral exanthems, meningococcemia) but is not a universal or primary indicator of *any* infectious cause [2]. - Many febrile illnesses do not present with a rash, and rashes can also be non-infectious in origin (e.g., allergic reactions). *Vomiting* - **Vomiting** can accompany many illnesses, both infectious (e.g., gastroenteritis, meningitis) and non-infectious (e.g., migraine, drug reaction). - It is a non-specific symptom that does not singularly point to an infectious etiology as strongly as rigors in the context of a high fever.

Infectious Diseases Indian Medical PG Question 4: Continued suppression of bacterial growth after antibiotic levels have fallen below the Minimum Inhibitory Concentration (MIC) is known as?

• A. Time dependent killing
• B. Sequential blockade
• C. Concentration dependent killing
• D. Post antibiotic effect (Correct Answer)

Infectious Diseases Explanation: ***Post antibiotic effect*** - The **post-antibiotic effect (PAE)** refers to the continued suppression of bacterial growth after antibiotic levels have fallen below the **Minimum Inhibitory Concentration (MIC)**. - This phenomenon allows for less frequent dosing while maintaining efficacy, which is important for drug scheduling. *Time dependent killing* - **Time-dependent killing** means that the duration for which the antibiotic concentration stays above the **MIC** is the most important factor for efficacy, not necessarily the peak concentration. - Antibiotics with this characteristic, such as **beta-lactams**, often require frequent dosing or continuous infusion. *Sequential blockade* - **Sequential blockade** occurs when two drugs act on consecutive steps in a metabolic pathway, leading to a synergistic effect that results in enhanced microbial killing. - A classic example is the combination of **sulfamethoxazole and trimethoprim**, which inhibit different enzymes in the folic acid synthesis pathway. *Concentration dependent killing* - **Concentration-dependent killing** indicates that the rate and extent of bacterial killing increase as the antibiotic concentration rises, particularly when it exceeds the **MIC**. - Antibiotics like **aminoglycosides** exhibit this effect, often benefiting from high peak concentrations to maximize efficacy.

Infectious Diseases Indian Medical PG Question 5: Which of the following is the most commonly used drug for outpatient management of community acquired pneumonia?

• A. Ceftriaxone
• B. Streptomycin
• C. Azithromycin (Correct Answer)
• D. Vancomycin

Infectious Diseases Explanation: ***Azithromycin*** - **Azithromycin** is a macrolide antibiotic widely recommended for outpatient treatment of **community-acquired pneumonia (CAP)** due to its efficacy against common causative pathogens like *Streptococcus pneumoniae* and **atypical bacteria** (e.g., *Mycoplasma pneumoniae*, *Chlamydophila pneumoniae*). - Its **once-daily dosing** and good oral bioavailability contribute to patient compliance in an outpatient setting. *Ceftriaxone* - **Ceftriaxone** is a third-generation cephalosporin primarily used for **intravenous administration** in more severe CAP cases requiring hospitalization or for specific resistant strains, not typically for initial outpatient management. - While effective against *Streptococcus pneumoniae*, it lacks coverage for **atypical pathogens** and its parenteral route makes it less suitable for most outpatient settings. *Streptomycin* - **Streptomycin** is an aminoglycoside antibiotic primarily used for **tuberculosis** and severe gram-negative infections, not a standard treatment for typical or atypical pathogens causing CAP. - It has a high risk of **ototoxicity** and **nephrotoxicity**, making it unsuitable for routine outpatient CAP management. *Vancomycin* - **Vancomycin** is a glycopeptide antibiotic primarily used for **methicillin-resistant *Staphylococcus aureus* (MRSA)** infections and severe gram-positive infections, not a first-line agent for typical CAP pathogens. - It is usually administered **intravenously** and requires monitoring for **nephrotoxicity** and **ototoxicity**, making it inappropriate for routine outpatient use.

Infectious Diseases Indian Medical PG Question 6: Which of the following statements about cephalosporins is false?

• A. Cefoperazone has got antipseudomonal effect.
• B. Cephalosporins act by inhibiting cell wall synthesis.
• C. Ceftazidime is a 3rd generation cephalosporin.
• D. Cefoxitin has no activity against anaerobes. (Correct Answer)

Infectious Diseases Explanation: ***Cefoxitin has no activity against anaerobes.*** - This statement is **false** because **cefoxitin** is a second-generation cephalosporin known for its **excellent activity against anaerobic bacteria**, particularly *Bacteroides fragilis*. - Its anaerobic coverage makes it useful for treating infections where these organisms are suspected, such as intra-abdominal and pelvic infections. *Ceftazidime is a 3rd generation cephalosporin.* - This statement is **true**. **Ceftazidime** is a third-generation cephalosporin characterized by its broad-spectrum activity, including significant coverage against **Pseudomonas aeruginosa**. - Its primary clinical utility is often in treating difficult Gram-negative infections. *Cefoperazone has got antipseudomonal effect.* - This statement is **true**. **Cefoperazone** is a third-generation cephalosporin that exhibits **antipseudomonal activity**, similar to ceftazidime. - It is often used for treating infections caused by **Pseudomonas aeruginosa** and other difficult Gram-negative bacteria. *Cephalosporins act by inhibiting cell wall synthesis.* - This statement is **true**. Like other beta-lactam antibiotics, **cephalosporins** exert their bactericidal effect by **inhibiting bacterial cell wall synthesis**. - They bind to and inactivate **penicillin-binding proteins (PBPs)**, which are essential enzymes involved in peptidoglycan cross-linking, leading to compromised cell wall integrity and bacterial lysis.

Infectious Diseases Indian Medical PG Question 7: Which of the following is a scoring system for severity of wound infection, and is particularly useful for surveillance and research ?

• A. Southampton grading system (Correct Answer)
• B. Apgar score
• C. Glasgow scoring system
• D. ASA classification

Infectious Diseases Explanation: ***Southampton grading system*** - The **Southampton grading system** is specifically designed for the **severity of wound infection**, offering a clear framework for classification based on clinical signs. - Its utility in **surveillance and research** stems from its structured and reproducible assessment, allowing for consistent data collection on wound healing and infection rates. *Apgar score* - The **Apgar score** is a rapid assessment of a **newborn's health** immediately after birth, evaluating heart rate, respiratory effort, muscle tone, reflex irritability, and color. - It is not used for assessing wound infection severity. *Glasgow scoring system* - The **Glasgow Coma Scale (GCS)** is used to assess the **level of consciousness** in a person following a brain injury, comprising eye opening, verbal, and motor responses. - It is not relevant to wound infection assessment. *ASA classification* - The **American Society of Anesthesiologists (ASA) Physical Status Classification System** is used to assess a patient's **overall health before surgery**, providing an indication of anesthetic risk. - It is not used for evaluating wound infection.

Infectious Diseases Indian Medical PG Question 8: Production of inactivating enzymes is an important mechanism of drug resistance for all of these antibiotics EXCEPT

• A. Quinolone (Correct Answer)
• B. Penicillin
• C. Chloramphenicol
• D. Aminoglycoside

Infectious Diseases Explanation: ***Quinolone*** - The primary mechanisms of resistance to **quinolones** involve mutations in the **gyrase** and **topoisomerase IV** enzymes or efflux pump overexpression, rather than enzymatic inactivation of the drug itself. - Unlike other antibiotic classes listed, quinolones are not typically susceptible to bacterial enzymes that degrade or modify their structure. *Penicillin* - **Penicillins** are highly susceptible to inactivation by **beta-lactamase enzymes**, which hydrolyze the beta-lactam ring, rendering the antibiotic ineffective. - This enzymatic degradation is a major mechanism of resistance developed by many bacterial species to penicillin and other beta-lactam antibiotics. *Chloramphenicol* - Resistance to **chloramphenicol** is primarily mediated by the enzyme **chloramphenicol acetyltransferase (CAT)**, which acetylates the drug, preventing its binding to the bacterial ribosome. - This enzymatic modification is a classic example of drug inactivation leading to resistance. *Aminoglycoside* - **Aminoglycosides** are frequently inactivated by a variety of **aminoglycoside-modifying enzymes (AMEs)**, such as acetyltransferases, phosphoryltransferases, and nucleotidyltransferases. - These enzymes add chemical moieties to the aminoglycoside molecule, preventing its binding to the bacterial ribosome and inhibiting protein synthesis.

Infectious Diseases Indian Medical PG Question 9: In a patient with suspected sepsis, which of the following is the MOST appropriate initial intervention?

• A. Start vasopressor support as first-line treatment
• B. Obtain blood cultures and start broad-spectrum antibiotics immediately (Correct Answer)
• C. Begin aggressive fluid restriction to prevent organ dysfunction
• D. Wait for culture results before starting any treatment

Infectious Diseases Explanation: ***Obtain blood cultures and start broad-spectrum antibiotics immediately*** - This is the **most appropriate initial intervention** following the **Surviving Sepsis Campaign Hour-1 Bundle** - Blood cultures should be obtained **before** antibiotics when possible, but antibiotic administration should not be delayed beyond 1 hour of sepsis recognition - **Early antibiotic therapy** (within 1 hour) significantly reduces mortality in sepsis - Broad-spectrum coverage is initiated empirically, then narrowed based on culture results and clinical response *Begin aggressive fluid restriction to prevent organ dysfunction* - This is **completely contraindicated** in sepsis management - Sepsis causes **vasodilation and capillary leak** leading to relative hypovolemia - The Surviving Sepsis Campaign recommends **aggressive fluid resuscitation** with 30 mL/kg crystalloid bolus within 3 hours - Fluid restriction would worsen **tissue hypoperfusion** and organ dysfunction *Start vasopressor support as first-line treatment* - Vasopressors are **second-line** therapy in sepsis - They should only be initiated when **fluid resuscitation alone** is insufficient to maintain MAP ≥65 mmHg - Starting vasopressors before adequate fluid resuscitation can worsen tissue perfusion *Wait for culture results before starting any treatment* - Sepsis is a **medical emergency** where every hour of delayed antibiotic therapy increases mortality by approximately 7-8% - Treatment must be initiated **immediately** based on clinical suspicion - Cultures are obtained to guide **de-escalation** of therapy, not to delay initiation

Infectious Diseases Indian Medical PG Question 10: Which of the following is NOT a quantitative method in the management of health services?

• A. System analysis
• B. Network analysis
• C. Planning programming budgeting system
• D. Management by objectives (Correct Answer)

Infectious Diseases Explanation: ***Management by objectives*** - **Management by objectives (MBO)** is a strategic management model that aims to improve organizational performance by clearly defining objectives that are agreed upon by both management and employees. - While MBO involves setting **quantifiable goals** and measurable outcomes, the methodology itself is primarily a **qualitative management philosophy** focused on communication, participation, integration, and alignment rather than mathematical modeling or statistical analysis. - Unlike true quantitative methods, MBO does not employ **mathematical algorithms, computational techniques, or statistical modeling** for decision-making—making it the correct answer to this "NOT quantitative" question. *System analysis* - **System analysis** is a quantitative method used to study and optimize complex systems by breaking them down into components to understand their interactions and behavior. - It involves **mathematical modeling, simulation, operations research, and data analysis** to identify bottlenecks, improve efficiency, and make data-driven decisions. *Network analysis* - **Network analysis** is a quantitative technique using mathematical algorithms to model and analyze relationships and flows within a system. - Applications include **project management (PERT/CPM)**, critical path method, resource allocation using computational techniques, and optimization algorithms. *Planning programming budgeting system* - **Planning Programming Budgeting System (PPBS)** is a comprehensive, quantitative approach to government planning and budgeting that links policy planning to resource allocation through numerical analysis. - It involves setting long-term goals, analyzing alternative programs using **cost-effectiveness analysis, benefit-cost ratios**, and allocating resources based on quantitative economic evaluation.

Infectious Diseases Flashcard 1 of 10

Question: According to NTEP, drug sensitivity testing for resistance is done through

Answer: Line probe assay

Infectious Diseases Flashcard 2 of 10

Question: _____ are those who had a subclinical infection and developed carrier state without suffering from overt disease

Answer: Healthy carriers

Infectious Diseases Flashcard 3 of 10

Question: The EYE strategy is a comprehensive and long term strategy targeting elimination of _____ epidemics by 2026

Answer: yellow fever

Infectious Diseases Flashcard 4 of 10

Question: Isolation is recommended until _____ hrs after the initiation of effective therapy in bacterial meningitis.

Answer: 24

Infectious Diseases Flashcard 5 of 10

Question: _____ test: Determines whether the chosen disinfectant is effective in actual hospital practice.

Answer: Kelsey and Maurer (In use)

Infectious Diseases Flashcard 6 of 10

Question: Surveillance indicators for AFP:Laboratory performance- All AFP case specimens must be processed in a _____-accredited laboratory

Answer: WHO

Infectious Diseases Flashcard 7 of 10

Question: Nosocomial _____ due to Pseudomonas are commonly associated with catheters

Answer: UTIs

Infectious Diseases Flashcard 8 of 10

Question: Type _____ poliovirus is the most common cause of epidemics in non-immune populations.

Answer: 1

Infectious Diseases Flashcard 9 of 10

Question: Classification of states/UTs according to the Annual Parasite Index (API): No answer _____

Answer: :)

Infectious Diseases Flashcard 10 of 10

Question: What are the contents of grey kit? _____ *partner rx?

Answer: