Bed bugs do not transmit MRSA. Although there have been reports of persons developing methicillin resistant Staphylococcus aureus (MRSA) infections, such as boils or abscesses associated with bed bug bites, it turns out the bed bugs really weren't directly at fault. Rather, the cases of MRSA infections associated with bed bug bites are actually an example of scratching leading to minor skin trauma and subsequent secondary bacterial infections. In these cases, people who are carriers of MRSA scratch at the itchy bite sites and provide a port of entry for the MRSA (which was already present on their skin) to get in and under the skin and cause the secondary infection. While it can be blamed for some other bed bug symptoms like itching and red welts, the bed bug cannot be blamed for the infection.
Jump up ^ Johann Friedrich Wolff; Johann Philip Wolff. "According to Scopoli's 2nd work (loc. cit.), found in Carniola and adjoining regions. According to Linnaeus' second work on exotic insects (loc. cit.), before the era of health, already in Europe, seldom observed in England before 1670". Icones Cimicum descriptionibus illustratae. p. 127. Retrieved 1 December 2016. fourth fascicle (1804)
The size of bed bug bites varies with a number of different factors. Bed bugs inject an anti-coagulant along with their saliva when they pierce the skin to take a blood meal. This anti-coagulant is mostly responsible for how a person reacts to the bite and determines the size of the bug’s bite. Since people will have various sensitivities to the bed bug’s bite, the size of the bite will vary, as well. Another factor that influences the size of a bed bug reaction is the number of times a person is bitten. Bite reactions of people bitten many times are also variable, and their response may be either more or less intense as the number of bites increases.