Infectious Agent Transmission Flashcards

An infection preventionist notes MRSA transmission persisting despite contact precautions. Which environmental factor should be investigated FIRST?

Answer: Adequacy of terminal room cleaning and disinfection practices

MRSA survives on environmental surfaces for extended periods; inadequate terminal cleaning is a common cause of ongoing contact transmission despite isolation precautions.

The concept of 'infectious dose' in transmission refers to:

Answer: The minimum number of pathogenic organisms needed to establish infection in a host

Infectious dose is the minimum number of organisms required to successfully establish infection in a susceptible host, and varies widely among different pathogens.

Hepatitis B virus (HBV) transmission in healthcare settings is MOST efficiently prevented by:

Answer: Vaccination of healthcare workers and use of standard precautions

HBV vaccination provides the most effective protection, and standard precautions (treating all blood/body fluids as infectious) prevent occupational exposure.

Which scenario represents vertical transmission of an infectious agent?

Answer: HIV transmission from a mother to her infant during delivery

Vertical transmission refers to pathogen transfer from parent to offspring, including transplacental, perinatal (during delivery), or breastfeeding transmission.

A hospital implements universal gloving for all patient contact. Which unintended consequence is MOST concerning for infection prevention?

Answer: Decreased hand hygiene compliance due to false sense of security

Universal gloving can create a false sense of security, leading to reduced hand hygiene compliance, which paradoxically increases transmission risk when gloves are not changed between patients.

Epiglottitis caused by Haemophilus influenzae type b (Hib) is transmitted primarily via which route?

Answer: Respiratory droplets from the nasopharynx of colonized or infected persons

Hib is transmitted via respiratory droplets from the nasopharyngeal secretions of colonized or infected individuals, requiring droplet precautions.

In outbreak investigation, the attack rate is most useful for:

Answer: Measuring the proportion of exposed individuals who develop illness, helping identify the source

The attack rate (number ill / number exposed × 100) helps identify the exposure source by comparing rates among those with different exposures during an outbreak.