Infectious resistance, definition

Initially, it was assumed that the HlV-1 population is infinite, evolution is deterministic, and antiretroviral resistance development is definite (Coffin 1995). However, our research amongst others has demonstrated that the effective population size, defined as the average number of HIV variants that produces infectious progeny is relatively small (Leigh Brown 1997 Leigh Brown and Richman 1997 Nijhnis et al. 1998). This can be explained because the majority of virus particles that are produced harbor deleterious mutations resulting in noninfectious virus. Also limited target cell availability and inactivation of potentially infectious viruses by the host... 

Patients are, for the most part, in a debilitated state in the hospital [12], and many of the nosocomial infectious agents, particularly bacteria, are antibiotic-resistant, even multiantibiotic-resistant. The microorganisms causing disease in patients who are admitted for diagnosed infectious disease are, by definition, virulent [13]. Hence, the spread of nosocomial infection in the hospital setting is a serious and ongoing problem. 

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