Hospital Infections


"Hospital infections are the most serious and common complication in the health care.
Are defined the infection occurred during hospitalization, or after discharge of the patient, but are neither present nor incubating upon the patient’s admission to the hospital. Are the effect of the progressive introduction of new health technologies, that if on one hand guarantee the survival in patients at high risk of infections, on the other allow the entry of microorganisms even in normally sterile body parts. Another crucial element to consider is the coming out of bacterial strains resistant to antibiotics, given the widespread use of these drugs as a prophylactic or therapeutic purpose.

In recent years, health care has undergone profound changes. While in the past hospitals were the place where took place the majority of care interventions, since the nineties are increased both patients hospitalized in serious condition (therefore at high risk of hospital infection), that the places of care outside the hospital (assisted healthcare residences for the elderly, home care, outpatient care). Hence the need to expand the concept of hospital infections to that of health care and social care associated infection (HAI).

Risk factors

People at risk of contracting a HAI are first of all the patients and, less frequently, the hospital staff, the assistants volunteers, the students and the trainees. Among the conditions that increase the susceptibility to infection there are:

  • Age (infants, elders)
  • Other infections or strong concomitant disorders (cancer, immune deficiency, diabetes, anaemia, heart disease, kidney failure)
  • Malnutrition
  • Trauma, burns
  • Alteration of the state of consciousness
  • Transplantation of organ.

Transmission mode

Here are the main transmission mechanisms of HAI:

  • direct contact between a healthy person and infected one, especially through hands
  • contact through droplets emitted in the act of the cough or sneeze from an infected person to a susceptible who is less than 50 cm
  • indirect contact through a contaminated vehicle (for example endoscopes or surgical instruments)
  • infection transmission to several people at the same time, through a common contaminated vehicle (food, blood, infusion liquids, disinfectants , etc.)
  • by air, by micro-organisms that survive in the air and are transmitted at a distance.

Type of infections

About 80% of all hospital infections covers four main locations: the urinary tract, the surgical wounds, the respiratory system, the systemic infections (sepsis, bacteremia). The most frequent are the urinary infections, which alone account for 35-40% of all hospital infections. However, in the last fifteen years we are witnessing to a decline in this type of infections (together with those of the surgical wound) and to an increase in bacteremia and pneumonia.

The increase in systemic infections is the consequence of a gradual increase of the specific risk factors, in particular the abundant use of antibiotics and of vascular catheterisms.

As for the involved microorganisms, they vary in time. Until the beginning of the eighties, hospital infections were due mainly to gram-negative bacteria (eg. E.coli and Klebsiella pneumoniae). Then, by the effect of antibiotic pressure and the increased use of health centers of plastic material, are increased the infections caused by gram-positive (especially Enterococci and Staphylococcus epidermidis) and those from fungi (especially Candida), while decreased those incurred by gram -negative.


The resistance to antibiotics

Among the gram-positive bacteria, those with increased resistance to antibiotics are Methicillin-resistant Staphylococcus aureus (-oxacillina), pneumococci resistant to beta-lactam and multi-resistant, the vancomycin-resistant enterococci. Among the gram-negative bacteria, the main resistance are the spread-spectrum beta-lactamases at spread-spectrum in Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, the high-level resistance to cephalosporins of third generation among species of Enterobacter and Citrobacter freundii, the multi-resistance observed in Pseudomonas aeruginosa, Acinetobacter and Stenotrophomonas maltophilia.


In addition, since 1988 have been reported in the United States numerous outbreaks of multidrug resistant tuberculosis in the hospital among HIV-positive patients. In the nineties similar reports have also been reported in Europe (Italy, Great Britain, France, Spain) all share a high lethality (72-90%) , from a short interval between exposure and development of the disease and between diagnosis and death . The multidrug resistant tuberculosis represents a significant risk to health care workers." (source:


  • Approximately 4.5 million cases
  • 37,000 dead
  • 16 million extra days of hospital stay
  • 7 billion euro in direct costs