An infection caused by an organism existing within the host, prior to the start of infection is:

IGNOU PB Bsc Nsg.Entrance-2026

Applied Microbiology & Infection control

Easy

Appeared in: IGNOU PB Bsc Nsg.Entrance-2026

Explanation

An endogenous infection is caused by microorganisms that are already part of the host's own body, often referred to as normal flora.
The question specifies the infection is from an 'organism existing within the host' before the infection began, which is the definition of an endogenous source.
This typically happens when the host's immune defenses are weakened or when the normal flora is translocated to a sterile site in the body, allowing it to cause disease.
A common example is a urinary tract infection (UTI) caused by Escherichia coli, which normally resides in the patient's own gastrointestinal tract.

Option B: This is incorrect because an exogenous infection originates from a source outside the body, such as another person or a contaminated object, which is the opposite of what the question describes.
Option C: This is incorrect because 'sub-clinical' describes the severity or presentation of an infection (i.e., without symptoms), not the origin of the pathogen.
Option D: This is incorrect because a 'mixed infection' refers to being infected with multiple types of pathogens simultaneously, which describes the composition of the infectious agents, not their source.

Clinical Relevance

Nursing practice connection: Knowing Classification of Infections by Source helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the source of infection is vital for nursing practice as it dictates the type of prevention strategies needed.
For endogenous infections, nursing interventions focus on maintaining the host's defenses and preventing the translocation of normal flora. This includes promoting good perineal hygiene, ensuring proper urinary catheter care, and advocating for judicious antibiotic use.
For exogenous infections, the focus is on breaking the chain of transmission through strict hand hygiene, use of personal protective equipment (PPE), and environmental disinfection.

How to Approach the Question

First, carefully read the question and identify the key defining phrase: 'organism existing within the host'.
Recognize that this phrase points to the source or origin of the infectious agent.
Evaluate each option based on its definition in the context of infection sources.
The prefix 'endo-' means 'within' or 'internal'. 'Endogenous' therefore means originating from within the body.
The prefix 'exo-' means 'outside' or 'external'. 'Exogenous' means originating from outside the body.
Match the key phrase 'existing within the host' to the definition of 'Endogenous'.

Concept Tested & Keywords

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E6 Nursing Fundamentals Taylor p. 167-169

E6 Nursing Fundamentals Potter Perry 12e Part 2 p. 221-223