Final answer:
Iatrogenic diseases, pre-existing conditions, and immune factors contribute to nosocomial infections in hospitals.
Step-by-step explanation:
Iatrogenic diseases, or diseases contracted as a result of medical procedures, can cause nosocomial infections. Factors contributing to the prevalence and severity of nosocomial diseases include the presence of pathogens in hospitals, transmission through improperly sterilized equipment or unclean hands, weakened immune systems of patients, and the use of antibiotics that can select for drug-resistant bacteria.
Pathogenicity of microorganisms is influenced by both virulence factors of the microbe and the immune defenses of the individual. Pre-existing conditions, environmental factors, and genetic immune factors may make some individuals more susceptible to infections. A better understanding of these interactions can help identify at-risk individuals and improve prophylactic interventions.