The term hospital infection, hospital-acquired infection, or nosocomial infection is applied to infections occurring in hospitalized patients who were neither infected nor were in incubation at the time of their admission to the hospital.
Approximately, 5% of hospitalized patients experience a nosocomial infection. Nosocomial infection represents an important public health problem in developing countries, as in developed ones today, and as a major cause of high morbidity, mortality, and economic consequences in hospitalized patients.
Factors Affecting Hospital-Acquired Infection
Hospitalized patients: Susceptible hospitalized patients are one of many factors responsible for hospital-acquired infections. This is because most patients admitted in wards have impaired immunity either as a part of their preexisting disease processes or, in some instances, due to the treatment they have received in the hospital. They are therefore highly susceptible to infection.
Hospital environment: The hospital environment harbors a higher load of microorganisms due to the multitudes of infected patients visiting the hospital. These organisms manage to infect the susceptible hosts through the medium of fomites in certain cases and through human carriers in others. Contamination of food, water, and in a few cases air has also been implicated in outbreaks of hospital infections.
Antibiotics resistance: The infectious agents present in the hospital environment also possess the dubious distinction of being more difficult to treat as they are usually resistant to a range of drugs which are used commonly. The initial resistant strains of bacteria are present in large numbers due to the constant selection pressure exerted because of the necessary antibiotic usage inside the hospitals and these then spread, replacing the other strains in the hospital.
Diagnostic or therapeutic procedures: Diagnostic or therapeutic interventions, such as insertion of intravenous or urethral catheters, may introduce infection to susceptible patients and cause iatrogenic infections. There is a good chance that hospital infections are caused by the patient’s own flora as many invasive procedures are carried out within the hospitals, which exposes them to this risk.
Transfusion: Transfusion of blood, blood products, and intravenous fluids, if not properly screened, may transmit blood-borne pathogens to the recipient hospitalized patients.