Microbiology and Infection Control Flashcards

A technician is reprocessing surgical instruments used on a patient with suspected Creutzfeldt-Jakob Disease (CJD). Which of the following microorganisms is the cause of this disease and is known for its extreme resistance to standard sterilization processes?

Answer: Prion

Prions are proteinaceous infectious particles that cause transmissible spongiform encephalopathies (TSEs), like CJD. They are exceptionally resistant to conventional cleaning, disinfection, and sterilization methods, requiring special, extended protocols.

A new sterile processing technician is learning about the classification of bacteria. The supervisor explains that the result of a Gram stain is determined by the composition of the bacterial cell wall. Which of the following correctly describes a key difference between Gram-positive and Gram-negative bacteria?

Answer: Gram-positive bacteria have a thick peptidoglycan layer and lack an outer membrane.

Gram-positive bacteria are characterized by a thick cell wall composed of many layers of peptidoglycan, and they do not have an outer membrane. This structure allows them to retain the crystal violet stain, appearing purple. Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane, which prevents them from retaining the crystal violet, so they are counterstained pink or red.

A healthcare worker touches a contaminated bed rail and then, without performing hand hygiene, touches a patient's intravenous (IV) site, leading to an infection. This scenario is an example of which mode of transmission?

Answer: Indirect contact transmission

Indirect contact transmission occurs when a susceptible host comes into contact with a contaminated inanimate object, known as a fomite. In this case, the bed rail is the fomite that transfers pathogens from a source to the patient via the healthcare worker's hands.

Which of the following environmental factors is essential for the growth and reproduction of virtually all microorganisms and is a key reason why instruments must be thoroughly dried before storage?

Answer: Moisture

Water, or moisture, is a fundamental requirement for microbial life, as it is essential for metabolic functions. Removing moisture by thoroughly drying instruments creates an environment that inhibits the growth of any remaining microorganisms, which is a critical step in preventing contamination during storage.

During the cleaning process, a technician notices a slimy, resistant layer on a complex surgical instrument that has been sitting for several hours before decontamination. This layer, which can protect microorganisms from disinfectants and sterilants, is known as:

Answer: A biofilm

A biofilm is a community of microorganisms that attach to a surface and are encased in a self-produced slimy, extracellular matrix. This matrix protects the embedded microbes, making them highly resistant to cleaning agents, disinfectants, and sterilants, which is why immediate point-of-use treatment and thorough cleaning are critical.

Certain types of bacteria, such as those from the Bacillus and Clostridium genera, can form a highly resistant, dormant structure to survive harsh environmental conditions like heat, chemicals, and desiccation. What is this structure called?

Answer: Spore

Bacterial spores (or endospores) are dormant, tough, non-reproductive structures produced by certain bacteria. They are extremely resistant to sterilization processes and are used as the challenge organism in biological indicators to verify the effectiveness of sterilization cycles.