Surgical Site 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?
What is the best way to control the MRSA infection in the ward?
Most common catheter related blood stream infection is
What is the term for bacteria that are actively dividing and have invaded the wound surface in the context of surgical site infection?
Drugs of choice for MRSA in skin and soft tissue infections are:
Most common injection site infection in spinal anaesthesia
A young 28-year-old male was operated for duodenal ulcer perforation peritonitis. After having recovered well for five days, he developed high fever with chills and symptoms of toxemia. He developed right shoulder tip pain and intractable hiccoughs. The most likely diagnosis is :
On the 4th postoperative day of laparotomy, a patient presents with bleeding and oozing from the wound. Management is:
An otherwise healthy patient who has just received a prosthetic aortic valve develops postoperative fever. Blood cultures are done and she is placed on broad-spectrum antibiotics. Two days later she is still febrile and clinically deteriorating. Which of the following organisms is the most probable etiologic agent?
Which infection commonly spreads to newborns through caregivers?
Surgical Site 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: What is the best way to control the MRSA infection in the ward?
- A. Fumigation of ward frequently
- B. Washing hand before and after attending patients (Correct Answer)
- C. Wearing masks during invasive procedures in ICU
- D. Vancomycin given empirically to all the patients
Explanation: **Washing hand before and after attending patients** - **Hand hygiene** is the single most effective measure in preventing the transmission of **healthcare-associated infections**, including **MRSA**. - **Healthcare workers' hands** are the primary vehicle for spreading pathogens from one patient to another. *Fumigation of ward frequently* - **Fumigation** is generally not recommended for routine infection control and has limited efficacy against resistant organisms like **MRSA** in this context. - It does not address the primary mode of transmission, which is direct contact via **contaminated hands** or surfaces. *Wearing masks during invasive procedures in ICU is important.* - While important for preventing infections during **invasive procedures** and protecting against **aerosolized pathogens**, masks are not the primary strategy for controlling the spread of **MRSA** in routine ward settings. - **MRSA transmission** is predominantly contact-based, not airborne. *Vancomycin given empirically to all the patients* - **Empirical broad-spectrum antibiotic use** for all patients is a significant driver of **antibiotic resistance**, including **MRSA**. - It should be reserved for patients with suspected or confirmed **MRSA infections** based on clinical criteria and culture results, not as a general preventive measure.
Question 3: Most common catheter related blood stream infection is
- A. Candida
- B. Coagulase negative staphylococci (Correct Answer)
- C. Coagulase positive staphylococci
- D. Gram negative organisms
Explanation: ***Coagulase negative staphylococci*** - **Coagulase-negative staphylococci** (CoNS), such as *Staphylococcus epidermidis*, are the most common cause of catheter-related bloodstream infections (CRBSIs). - These bacteria colonize the skin and can easily contaminate the insertion site, forming **biofilms** on the catheter surface. *Candida* - While *Candida* species can cause CRBSIs, especially in immunocompromised patients or those on broad-spectrum antibiotics, they are less common than coagulase-negative staphylococci. - **Fungal infections** often require different antimicrobial treatments than bacterial infections. *Coagulase positive staphylococci* - **Coagulase-positive staphylococci**, primarily *Staphylococcus aureus*, are significant causes of CRBSIs, known for their virulence and ability to cause severe infections. - However, they are still **less frequently isolated** in CRBSIs than coagulase-negative staphylococci. *Gram negative organisms* - **Gram-negative bacteria**, such as *Klebsiella*, *Pseudomonas*, and *Escherichia coli*, can cause CRBSIs, particularly in critically ill patients or those with urinary tract infections. - While important, they are not the **most common** cause of CRBSIs compared to staphylococci.
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: Drugs of choice for MRSA in skin and soft tissue infections are:
- A. Clindamycin, Vancomycin
- B. Vancomycin, Linezolid (Correct Answer)
- C. Vancomycin, Teicoplanin
- D. Dicloxacillin, Vancomycin
Explanation: ***Vancomycin, Linezolid*** - **Vancomycin** is a cornerstone for treating **MRSA** infections, particularly severe ones, due to its efficacy against resistant staphylococci. - **Linezolid** is an alternative for **MRSA** infections, especially in cases of vancomycin resistance or intolerance, and offers good oral bioavailability. *Clindamycin, Vancomycin* - While **vancomycin** is correct, **clindamycin** has varying efficacy against **MRSA** and high rates of inducible resistance, making it less reliable as a primary drug of choice. - Clindamycin's use for MRSA often requires initial susceptibility testing, including a **D-test**, to rule out inducible clindamycin resistance. *Vancomycin, Teicoplanin* - **Vancomycin** is a primary **MRSA** drug, but **teicoplanin** is largely used in Europe and is structurally similar to vancomycin, often reserved for cases where vancomycin is not tolerated or preferred. - While effective, **teicoplanin** is not as universally recognized as a first-line option alongside vancomycin in all regions. *Dicloxacillin, Vancomycin* - **Vancomycin** is appropriate, but **dicloxacillin** is an **anti-staphylococcal penicillin** and is not effective against **MRSA** (Methicillin-Resistant Staphylococcus aureus) because MRSA, by definition, is resistant to all beta-lactam antibiotics. - Dicloxacillin is mainly used for **MSSA** (Methicillin-Sensitive Staphylococcus aureus) infections.
Question 6: Most common injection site infection in spinal anaesthesia
- A. Bacteroides
- B. Staphylococcus (Correct Answer)
- C. Pseudomonas
- D. Streptococcus
Explanation: **Staphylococcus** - **_Staphylococcus_** species, particularly methicillin-sensitive _Staphylococcus aureus_ (MSSA) and methicillin-resistant _Staphylococcus aureus_ (MRSA), are the **most common culprits** in post-procedural infections like those following spinal anesthesia due to their presence on the skin. - These bacteria can cause various infections, from **superficial cellulitis** at the injection site to more serious complications like **meningitis** or an **epidural abscess**. *Bacteroides* - **_Bacteroides_** species are **anaerobic bacteria** commonly found in the gut flora, making them less likely to cause skin-puncture infections unless there is bowel injury or contamination. - While they can cause serious infections, they are **not typically associated** with superficial skin contamination leading to spinal anesthesia infections. *Pseudomonas* - **_Pseudomonas aeruginosa_** is known for causing opportunistic infections, especially in healthcare settings and in contact with water sources, but it is **not the most common cause** of injection site infections following spinal procedures. - Infections with **_Pseudomonas_** often present with a distinctive **grape-like odor** and a blue-green pus, which is not the typical presentation for initial injection site infections. *Streptococcus* - **_Streptococcus_** species can cause skin infections, but they are generally **less common than _Staphylococcus_** in injection site infections after spinal anesthesia. - While **Group A _Streptococcus_** can cause severe skin and soft tissue infections, it typically presents with **rapidly spreading cellulitis** rather than focal injection site issues.
Question 7: A young 28-year-old male was operated for duodenal ulcer perforation peritonitis. After having recovered well for five days, he developed high fever with chills and symptoms of toxemia. He developed right shoulder tip pain and intractable hiccoughs. The most likely diagnosis is :
- A. Subphrenic abscess (Correct Answer)
- B. Right lobe liver abscess
- C. Surgical site infection
- D. Postoperative peritonitis
Explanation: ***Subphrenic abscess*** - The development of **high fever with chills**, **toxemia**, **right shoulder tip pain**, and **intractable hiccups** following a duodenal ulcer perforation repair strongly suggests a subphrenic abscess. - **Diaphragmatic irritation** by the abscess causes referred shoulder pain (due to phrenic nerve irritation) and hiccups. *Right lobe liver abscess* - While a liver abscess can cause fever and chills, **shoulder tip pain** and **hiccups** are less typical compared to a subphrenic abscess, unless the abscess is very superficial and irritating the diaphragm. - A liver abscess often presents with **right upper quadrant pain** and hepatomegaly, which are not mentioned. *Surgical site infection* - A surgical site infection would typically manifest with **localized pain**, **redness**, **swelling**, and possibly **pus discharge** at the incision site, rather than referred shoulder pain or intractable hiccups. - While it can cause fever and toxemia, the specific constellation of symptoms points away from a superficial wound infection. *Postoperative peritonitis* - Postoperative peritonitis would present with more generalized **abdominal pain**, **distension**, **tenderness**, and potentially signs of evolving **sepsis** or **organ dysfunction**. - While it can cause fever and toxemia, the distinct symptoms of **shoulder tip pain** and **hiccups** are less characteristic of diffuse peritonitis.
Question 8: On the 4th postoperative day of laparotomy, a patient presents with bleeding and oozing from the wound. Management is:
- A. be
- B. Start broad-spectrum antibiotics for wound infection
- C. Check coagulation profile and correct any coagulopathy (Correct Answer)
- D. Immediate re-exploration under general anesthesia
- E. Apply tight abdominal binder and observe
Explanation: ***Correct Option: Check coagulation profile and correct any coagulopathy*** - **Postoperative bleeding and oozing on day 4** most commonly indicates a **coagulation abnormality** - The priority is to investigate with **PT/INR, aPTT, platelet count, and bleeding time** - Common causes include **anticoagulant therapy, vitamin K deficiency, liver dysfunction, or DIC** - Management involves **correcting the underlying coagulopathy** with fresh frozen plasma, vitamin K, platelet transfusion, or specific factor replacement as indicated - Local measures like pressure dressing and wound packing are adjunctive *Incorrect Option: Immediate re-exploration under general anesthesia* - Re-exploration is indicated for **major intra-abdominal bleeding or hemodynamic instability**, not for wound oozing - Wound bleeding on day 4 is typically managed conservatively unless there is **evidence of significant hematoma or active vessel bleeding** - Immediate surgery would be premature without first assessing coagulation status *Incorrect Option: Apply tight abdominal binder and observe* - A tight binder can provide **local compression** but does not address the underlying cause of bleeding - **Observation alone is inadequate** without investigating the coagulation status - This approach risks missing a correctable coagulopathy and allowing continued blood loss *Incorrect Option: Start broad-spectrum antibiotics for wound infection* - While **wound infection** can cause bleeding (due to tissue inflammation and vessel erosion), this typically presents with other signs like **fever, purulent discharge, erythema, and warmth** - **Oozing and bleeding alone** on day 4 is more suggestive of coagulopathy than infection - Antibiotics would be indicated if infection is confirmed, but investigating coagulation is the priority
Question 9: An otherwise healthy patient who has just received a prosthetic aortic valve develops postoperative fever. Blood cultures are done and she is placed on broad-spectrum antibiotics. Two days later she is still febrile and clinically deteriorating. Which of the following organisms is the most probable etiologic agent?
- A. Nocardia asteroides
- B. Actinomyces israelii
- C. Histoplasma capsulatum
- D. Candida albicans (Correct Answer)
Explanation: ***Candida albicans*** - *Candida albicans* is a common cause of **early prosthetic valve endocarditis**, especially in patients with prolonged hospitalization, broad-spectrum antibiotic use, or central venous catheters [1]. - The patient's clinical deterioration despite broad-spectrum antibacterial antibiotics suggests a **fungal etiology**, as bacteria are typically covered by such therapy [2]. *Nocardia asteroides* - *Nocardia asteroides* typically causes **pulmonary or cutaneous infections** in immunocompromised individuals, less commonly endocarditis. - It would usually respond to specific antibiotics like **trimethoprim-sulfamethoxazole**, and its presentation as prosthetic valve endocarditis is rare. *Actinomyces israelii* - *Actinomyces israelii* causes **actinomycosis**, characterized by chronic, slowly progressive infections with abscesses and draining sinuses, often following oral or abdominal trauma. - While it can cause endocarditis, it is less common in the context of acute prosthetic valve infection and would likely present with a more indolent course. *Histoplasma capsulatum* - *Histoplasma capsulatum* is a **dimorphic fungus** endemic to the Ohio and Mississippi River valleys, primarily causing pulmonary infections. - Disseminated histoplasmosis with endocarditis is rare and typically occurs in immunocompromised patients, not usually in an otherwise healthy individual post-surgery.
Question 10: Which infection commonly spreads to newborns through caregivers?
- A. Candida parapsilosis (Correct Answer)
- B. Candida albicans
- C. Candida tropicalis
- D. Candida glabrata
Explanation: ***Candida parapsilosis*** - This species is a well-known cause of **nosocomial bloodstream infections** in neonates, particularly in **premature infants** and those with central venous catheters. It is often spread via the hands of **healthcare workers**. - Its ability to form **biofilms on medical devices** (like catheters) further facilitates its transmission and makes it a significant infectious agent in neonatal intensive care units (NICUs). *Candida albicans* - While *Candida albicans* is the **most common Candida species** causing infections in humans, including superficial and invasive candidiasis in neonates, its transmission is less frequently linked to direct caregiver spread in the context of outbreaks compared to *C. parapsilosis*. - Neonatal *C. albicans* infections are often acquired **vertically from the mother** or through endogenous gut colonization. *Candida tropicalis* - *Candida tropicalis* can cause **invasive candidiasis**, especially in immunocompromised patients, but it is less frequently implicated in **outbreaks** attributed to hand-to-patient transmission by caregivers in NICUs than *C. parapsilosis*. - It is often associated with **neutropenia** and broad-spectrum antibiotic use. *Candida glabrata* - *Candida glabrata* is a significant pathogen, particularly in adults and immunocompromised individuals, known for its **fluconazole resistance**. - While it can cause bloodstream infections, it is not typically recognized as a primary cause of **caregiver-spread outbreaks** in newborns to the same extent as *C. parapsilosis*.
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