Infections related to health care are a major public health problem in Spain, Europe and worldwide. They cause an increase in hospital stays, long-term disability, greater resistance of microorganisms to antimicrobials, additional costs both for the patient himself and for the health system, and unnecessary deaths. The patient is exposed to a wide variety of microorganisms during hospitalization. The potential for exposure leading to infection depends, in part, on the characteristics of the microorganisms, including antimicrobial resistance, intrinsic virulence, and the amount of infectious material (inoculum). The problem of greatest clinical importance is the trend of increasing bacterial resistance, becoming a health threat of great magnitude worldwide, since it causes a decrease in the safety of healing processes and causes an increase in morbidity and mortality. The incidence of bacterial resistance is also related to the prescription and consumption of antimicrobials. The main objective of this bibliographic review is to analyze the current microbiological trends of the microorganisms that cause nosocomial infections.
Key words: nosocomial infections, microorganisms, antimicrobial resistance.