Infectious Agent Transmission Flashcards

A patient with suspected pulmonary tuberculosis is admitted to an acute care hospital. Which of the following combinations of precautions is MOST appropriate to prevent the transmission of this infectious agent?

Answer: Airborne Precautions, including the use of an N95 respirator and placement in an airborne infection isolation room (AIIR).

Tuberculosis is transmitted via the airborne route, through small droplet nuclei that can remain suspended in the air for extended periods. Therefore, Airborne Precautions are required. This includes placing the patient in an airborne infection isolation room (AIIR), which is a negative pressure room, and requiring healthcare personnel to wear a fit-tested N95 or higher-level respirator.

An Infection Preventionist is investigating a cluster of C. difficile infections on a medical unit. Which of the following represents the primary mode of transmission for this pathogen in a healthcare setting?

Answer: Indirect contact transmission via contaminated surfaces and hands of healthcare workers.

Clostridioides difficile (C. difficile) spores can survive for long periods on environmental surfaces and are not effectively killed by alcohol-based hand rubs. The primary mode of transmission is through indirect contact, where healthcare workers' hands become contaminated from the patient's environment or equipment and then transmit the spores to other patients.

Which component of the chain of infection is broken by ensuring patients with influenza wear a surgical mask when being transported outside of their room?

Answer: Portal of Exit

The chain of infection consists of six links: the infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. By having a patient with influenza wear a mask, the intervention is controlling the dispersal of infectious droplets from the respiratory tract (the portal of exit), thereby breaking the chain at that point.

A healthcare worker is caring for a patient with confirmed influenza. According to CDC guidelines, Droplet Precautions should be implemented. This includes which of the following practices?

Answer: Wearing a surgical mask when working within 3-6 feet of the patient.

Droplet Precautions are for pathogens transmitted by respiratory droplets generated by coughing, sneezing, or talking. These droplets travel short distances (typically 3-6 feet). Therefore, wearing a surgical mask is required for close contact. An N95 respirator is for airborne pathogens, and a special air handling room like a negative-pressure AIIR (not positive-pressure) is for airborne precautions.

Which of the following scenarios describes vector-borne transmission of an infectious agent?

Answer: A person develops Lyme disease after being bitten by an infected tick.

Vector-borne transmission involves the transfer of an infectious agent by a living organism, such as an insect or animal. Lyme disease is a classic example, transmitted to humans through the bite of an infected tick. The other options describe bloodborne, common vehicle (fomite), and indirect contact transmission, respectively.

To interrupt the transmission of pathogens, the 'portal of entry' in the chain of infection must be protected. Which of the following is a key strategy for protecting this link?

Answer: Performing meticulous wound care and maintaining intact skin.

The portal of entry is the path by which a pathogen enters a new host. Portals can include mucous membranes, non-intact skin (like wounds or surgical incisions), and the respiratory tract. Performing proper wound care and maintaining the integrity of a patient's skin directly protects a common portal of entry. While other options are important infection control measures, they address different links in the chain (infectious agent, mode of transmission, and infectious agent identification).