This pathogen is the leading cause of hospital-acquired infections and can be difficult to treat:

A) Clostridia.

B) Shigella.

C) Anthrax.

D) Pseudomonas.

D) Pseudomonas

Explanation:

Pseudomonas is the group of gram negative bacteria which are considered opportunistic pathogens. This means that they infect in presence of an already existing ailment like cystic fibrosis. They usually target immuno compromised people.

Normally they are present on soil, water and skin. They are a major cause of hospital acquired infections like sepsis syndrome and ventilator-associated pneumonia. They thrive in moist conditions hence can be found on medical equipment causing cross infections in hospitals. They are resistant to many antibiotics hence the treatment is difficult.