Surgical Infections — MCQs
In a surgical post-op ward, a patient developed wound infection. Subsequently 3 other patients developed similar infections in the ward. What is the most effective way of preventing the spread of infection?
Commonest cause of nosocomial infection is
Gas gangrene can be caused by all Except
What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?
Which of the following statements about burns is NOT true?
What is the most common cause of postoperative fever within 24 hours?
What is the most common cause of postoperative fever on the first postoperative day?
In a female with appendicitis in pregnancy the treatment of choice is:
Which type of retractor is shown in the image?
Which type of surgery is laparoscopic cholecystectomy classified as?
Surgical Infections Indian Medical PG Practice Questions and MCQs
Question 1: In a surgical post-op ward, a patient developed wound infection. Subsequently 3 other patients developed similar infections in the ward. What is the most effective way of preventing the spread of infection?
- A. Fumigation of the ward
- B. Wash OT instruments with 1% perchlorate
- C. Proper hand washing of all ward personnel (Correct Answer)
- D. Give IV antibiotics to all patients in the ward
Explanation: ***Proper hand washing of all ward personnel*** - **Hand hygiene** is the single most important and effective measure to prevent the spread of **healthcare-associated infections (HAIs)**, especially in a ward where multiple patients are affected. - It directly reduces the transmission of microorganisms from healthcare workers to patients and between patients. *Fumigation of the ward* - **Fumigation** is typically used for **terminal disinfection** or in situations involving highly resistant organisms or outbreaks, but it is not a routine or primary method for preventing day-to-day infection spread. - Its effectiveness is limited, and it can pose **health risks** to personnel and patients if not performed correctly, often requiring the ward to be vacated. *Wash OT instruments with 1% perchlorate* - This option focuses on the **sterilization of operating theater (OT) instruments**, which is crucial for surgical procedures but **irrelevant** to preventing the spread of wound infection within a general ward setting. - The problem describes a ward-based infection spread, not issues with surgical instrument sterility. *Give IV antibiotics to all patients in the ward* - **Prophylactic antibiotics** for all patients in a ward is generally **not recommended** as it can lead to **antibiotic resistance**, mask underlying infections, and cause adverse drug reactions. - Antibiotics should be prescribed judiciously based on specific indications and confirmed infections, not as a general preventive measure.
Question 2: Commonest cause of nosocomial infection is
- A. Staphylococci (Correct Answer)
- B. Klebsiella
- C. Enterobacteriaceae
- D. Pseudomonas
Explanation: ***Staphylococci*** - **Staphylococci**, particularly *Staphylococcus aureus* (including MRSA) and coagulase-negative staphylococci, are the **most common cause** of nosocomial infections according to current surveillance data from CDC, WHO, and Indian hospital studies. - They are the leading cause of **surgical site infections**, **catheter-related bloodstream infections**, **ventilator-associated pneumonia**, and **skin and soft tissue infections** in hospital settings. - Their ability to form biofilms on medical devices, antibiotic resistance (especially MRSA), and widespread colonization of healthcare workers and patients make them the predominant nosocomial pathogen. *Enterobacteriaceae* - The family **Enterobacteriaceae** (including *E. coli*, *Klebsiella*, *Enterobacter*) represents a major group of gram-negative nosocomial pathogens. - They are very common causes of **urinary tract infections**, **pneumonia**, and **bloodstream infections**, particularly associated with indwelling catheters and ventilators. - While collectively representing a large proportion of nosocomial infections, they are the **second most common** group after Staphylococci in most contemporary studies. *Pseudomonas* - *Pseudomonas aeruginosa* is an important nosocomial pathogen, particularly in **ventilator-associated pneumonia**, **burn infections**, and infections in immunocompromised patients. - It accounts for approximately 10-15% of nosocomial infections and is especially problematic due to its intrinsic antibiotic resistance. *Klebsiella* - **Klebsiella** (particularly *K. pneumoniae*) is a member of the Enterobacteriaceae family and an important individual pathogen causing **pneumonia** and **urinary tract infections** in healthcare settings. - While a common pathogen, it represents only a subset of both the Enterobacteriaceae family and overall nosocomial infections, making it less common than the entire Staphylococci group.
Question 3: Gas gangrene can be caused by all Except
- A. Clostridium sporogenes
- B. Clostridium difficile (Correct Answer)
- C. Clostridium septicum
- D. Clostridium bifermentans
Explanation: ***Clostridium difficile*** - *Clostridium difficile* is primarily known for causing **pseudomembranous colitis** and **antibiotic-associated diarrhea**, not gas gangrene. - Its pathogenic mechanisms involve **toxins A and B** which cause colonic inflammation and damage, distinct from the tissue destruction and gas production seen in gas gangrene. *Clostridium sporogenes* - *Clostridium sporogenes* is an anaerobic bacterium that can produce **gas** and contribute to **tissue necrosis** in mixed infections, including gas gangrene. - While not one of the most common causes, it possesses enzymatic capabilities that can degrade tissues and support the anaerobic environment characteristic of gas gangrene. *Clostridium septicum* - *Clostridium septicum* is a significant cause of **spontaneous gas gangrene**, especially in patients with **hematological malignancies** or **colonic pathologies**. - It is highly invasive and can rapidly spread through tissues, producing potent toxins that lead to extensive myonecrosis and gas formation. *Clostridium bifermentans* - *Clostridium bifermentans* is one of the less common species of *Clostridium* that can cause **gas gangrene**, particularly in **polymicrobial infections**. - It is capable of producing **proteolytic enzymes** that contribute to tissue destruction and the characteristic foul-smelling discharge associated with clostridial myonecrosis.
Question 4: What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?
- A. Contamination
- B. Colonization
- C. Local infection
- D. Infection (Correct Answer)
Explanation: ***Infection*** - This term precisely describes bacteria that are **actively dividing** and have **invaded the host tissue**, causing a clinical infection with tissue damage and host immune response. - In surgical site infections, this represents the stage where microorganisms have overcome host defenses and are causing disease. - This is the standard terminology used in surgical literature to describe the progression from contamination to active disease. *Contamination* - **Contamination** refers to the presence of microorganisms on a surface or in a wound without active proliferation or host response. - It's an early stage where bacteria are present but not yet multiplying or causing disease. *Colonization* - **Colonization** indicates that microorganisms are replicating on the host surface or in a wound without tissue invasion or causing an immune response. - Unlike infection, colonization does not involve invasion of tissue or clinical signs of disease. *Local infection* - While this describes an infection confined to a particular anatomical area, it is a descriptor of the **location** rather than the **process** described in the question. - The question asks specifically about the term for dividing and invading bacteria, which is simply "infection" - the word "local" adds information about location but doesn't define the fundamental process.
Question 5: Which of the following statements about burns is NOT true?
- A. Pseudomonas is a common infection in burn wounds.
- B. Cephalosporins are not the drug of choice for burn management.
- C. Moist dressings are beneficial for burn care. (Correct Answer)
- D. Toxic shock syndrome is uncommon in burn patients.
Explanation: ***Moist dressings are beneficial for burn care.*** - This statement is **NOT true** in the traditional sense being implied here. - While **modern wound care** does favor maintaining a moist wound environment for many wound types, **burn management** specifically uses **topical antimicrobial agents** (like silver sulfadiazine, mafenide acetate) rather than simple "moist dressings." - Traditional moist dressings without antimicrobial properties can actually **increase infection risk** in burns. - The key principle is **antimicrobial coverage**, not just maintaining moisture. *Pseudomonas is a common infection in burn wounds.* - **Pseudomonas aeruginosa** is indeed one of the most common and serious pathogens in burn wounds. - It thrives in the moist, protein-rich environment of burn injuries and is notoriously difficult to treat due to antibiotic resistance. - Pseudomonas infection significantly increases morbidity and mortality in burn patients. *Cephalosporins are not the drug of choice for burn management.* - This statement is **TRUE**. - **Topical antimicrobials** (silver sulfadiazine, mafenide acetate, silver-impregnated dressings) are the primary agents for burn wound management. - Systemic antibiotics, including cephalosporins, are **not used prophylactically** and are reserved for documented infections. - When systemic treatment is needed, it is **culture-guided**, and for Pseudomonas coverage, anti-pseudomonal agents are preferred. *Toxic shock syndrome is uncommon in burn patients.* - **Toxic Shock Syndrome (TSS)** from *Staphylococcus aureus* or *Streptococcus pyogenes* is indeed a **rare but serious complication** in burn patients. - While burns create a susceptible environment for bacterial colonization, TSS remains uncommon compared to other infectious complications.
Question 6: What is the most common cause of postoperative fever within 24 hours?
- A. Sepsis
- B. Deep vein thrombosis
- C. Atelectasis (Correct Answer)
- D. Wound infection
Explanation: ***Atelectasis*** - **Atelectasis** is the most common cause of **postoperative fever** within the **first 24-48 hours** after surgery. - It results from the collapse of a portion of the lung, usually due to shallow breathing and reduced sigh reflexes under anesthesia, leading to **inflammation** and a mild fever. *Sepsis* - **Sepsis** is a systemic inflammatory response to infection and typically presents with a **high fever**, **tachycardia**, and **hypotension**. - While serious, it is rare for sepsis to manifest as the *most common cause* of fever within the first 24 hours, usually requiring more time for bacterial growth and systemic spread. *Deep vein thrombosis* - **Deep vein thrombosis (DVT)** typically causes fever *later* in the postoperative course, often **3-7 days after surgery**, and is characterized by leg pain, swelling, and redness. - Fever associated with DVT is usually due to the inflammatory response to the clot itself or a resulting **pulmonary embolism**, not an immediate post-operative complication. *Wound infection* - **Wound infections** usually develop **4-7 days postoperatively**, as this timeframe is needed for bacterial proliferation and the inflammatory response to become clinically apparent. - Early fevers (<24 hours) are rarely due to wound infection unless there is significant contamination during surgery, which is uncommon.
Question 7: What is the most common cause of postoperative fever on the first postoperative day?
- A. Atelectasis (Correct Answer)
- B. Wound infection
- C. Pulmonary embolism
- D. UTI
Explanation: ***Atelectasis*** - **Atelectasis** is the most common cause of fever on the **first postoperative day** due to the collapse of lung alveoli, leading to impaired gas exchange. - It is frequently caused by **anesthesia, pain, and immobility** reducing deep breaths and coughing. *Wound infection* - **Wound infections** typically manifest later, generally around **3 to 7 days post-surgery**, as bacterial growth and inflammation require more time. - While it can cause fever, it is unlikely to be the cause within the **first 24-48 hours**. *Pulmonary embolism* - A **pulmonary embolism** is a serious complication, but fever is not its primary or most common early symptom; instead, patients often present with **dyspnea, tachypnea, and chest pain.** - Although it can occur, it's generally less frequent on the **first postoperative day** compared to atelectasis. *UTI* - **Urinary tract infections (UTIs)** usually develop a few days after surgery, often associated with **catheterization**, and present with dysuria, frequency, and suprapubic pain. - While fever can occur with a UTI, it is rarely the cause of fever within the **first 24 hours** after surgery.
Question 8: In a female with appendicitis in pregnancy the treatment of choice is:
- A. Continue pregnancy with medical Rx
- B. Surgery after delivery
- C. Surgery at earliest (Correct Answer)
- D. Abortion with appendectomy
Explanation: ***Surgery at earliest*** - **Prompt surgical intervention** is crucial for appendicitis in pregnancy to prevent complications such as perforation, peritonitis, and maternal or fetal morbidity and mortality. - Delaying surgery increases the risk of rupture, which can be devastating for both the mother and the fetus. *Continue pregnancy with medical Rx* - **Medical management (antibiotics alone)** is generally ineffective for acute appendicitis in pregnant women and carries a high risk of progression to perforation. - This approach would expose the mother and fetus to serious complications, including sepsis and preterm labor, without addressing the underlying surgical pathology. *Surgery after delivery* - Delaying surgery until after delivery is unsafe and potentially fatal, as **appendiceal rupture could occur at any time** during pregnancy. - The risk of **perforation, peritonitis, and subsequent complications** is too high to justify waiting. *Abortion with appendectomy* - **Therapeutic abortion** is not indicated for uncomplicated appendicitis in pregnancy and does not improve the maternal prognosis for the appendicitis itself. - The focus is on treating the underlying medical condition (appendicitis) while preserving the pregnancy, if possible.
Question 9: Which type of retractor is shown in the image?
- A. Morris retractor (Correct Answer)
- B. Czerny retractor
- C. Richardson retractor
- D. Lower lid retractor
Explanation: ***Morris retractor (Correct Answer)*** - The image displays a **Morris retractor**, characterized by its slightly curved blade and often a single, broad blade or sometimes two blades for wider retraction. - It is a type of **hand-held retractor**, commonly used in general surgery, orthopedic surgery, and some deep abdominal procedures to retract skin, subcutaneous tissue, and muscle. *Czerny retractor (Incorrect)* - A Czerny retractor typically has **two L-shaped blades** that can be of different lengths, allowing fine adjustment for delicate tissue retraction. - It is often seen in **more superficial surgeries** and less for deep muscle retraction. *Richardson retractor (Incorrect)* - A Richardson retractor usually has a **single, right-angled blade** that is L-shaped, and the handle is often wider for a better grip. - It is also a **hand-held retractor** frequently used for medium depth retraction in various surgical fields. *Lower lid retractor (Incorrect)* - A lower lid retractor is specifically designed for **ophthalmic surgery**, used to gently hold down the lower eyelid. - It has a very **small, delicate, and often curved or spoon-shaped blade** suitable for the delicate tissues around the eye, which is clearly not what is depicted in the image.
Question 10: Which type of surgery is laparoscopic cholecystectomy classified as?
- A. Clean contaminated (Correct Answer)
- B. Dirty
- C. Contaminated
- D. Clean
Explanation: ***Clean contaminated*** - This classification applies to surgeries that involve a **viscus** (e.g., gallbladder, gastrointestinal tract, respiratory tract) but with **no unusual contamination** encountered. - While the gallbladder contains bile, which harbors bacteria, in an uncomplicated laparoscopic cholecystectomy, spillage is controlled, and there's no pre-existing infection. *Dirty* - This category is reserved for procedures performed in the presence of **established infection**, such as an abdominal abscess or perforated viscus with gross spillage. - There is evidence of **pus** or a **perforated hollow viscus** encountered during the operation. *Contaminated* - This classification is used when there is a **major break in sterile technique** or a significant spillage from the gastrointestinal contents or infected bile. - It also includes procedures where **acute, non-purulent inflammation** is encountered, or an open, traumatic wound is less than 4 hours old. *Clean* - These are procedures in which there is **no inflammation**, the gastrointestinal, genitourinary, or respiratory tracts are **not entered**, and there is no break in aseptic technique. - Examples include breast biopsies, hernia repairs without bowel resection, and thyroidectomies.
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