Final answer:
Healthcare-associated Serratia infections are typically spread through contaminated medical equipment, not vector-borne transmission. In a healthcare setting, vectors such as insects or ticks are not the usual mode of transmitting these infections.
Step-by-step explanation:
The most likely mode of transmission for healthcare-associated Serratia infections is not vector-borne but rather through contaminated medical equipment. Such bacteria can be introduced into the environment or a patient's body via devices such as ventilators and through processes like intubation. This type of transmission falls under the category of nosocomial infections, which are acquired within healthcare settings.
Vector-borne transmission involves the spread of pathogens through carriers like insects or ticks, as is the case with diseases such as malaria or Lyme disease. In the healthcare setting, however, vectors are generally not involved with the spread of Serratia; instead, the bacteria are more commonly spread through contact with contaminated surfaces or equipment.