November 27, 2019, 9:36 707

hospital-acquired infection (HAI), also known as a nosocomial infection, is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a health care–associated infection (HAI or HCAI). This type an infection can be acquired in hospital, nursing home, rehabilitation facility, outpatient clinic, or other clinical settings. Infection is spread to the patient in the clinical setting by various ways. Health care staff also spread infection, in addition to contaminated equipment, bed linens, or air droplets. The infection can originate from the outside environment, another infected patient, staff that may be infected, or in some cases, the source of the infection cannot be determined. Hospital infection may be exogenous or endogenous in origin. The exogenous source may be another person in the hospital (cross-infection) or a contaminated item of equipment or building service (environmental infection). A high proportion of clinically apparent hospital infections are endogenous (self-infection), the infecting organism being derived from the patient's own skin, gastrointestinal or upper respiratory flora.

Most infections acquired in hospital are caused by micro-organisms that are commonly present as commensals in the general population. Thus, contact with micro-organisms is seldom the sole or main event predisposing to infection. Various risk factors, alone or in combination, influence the frequency and nature of hospital infection. In comparing rates of HAI it is important to be aware of the frequencies of risk factors such as age, drug treatment or preexisting diseases in the population surveyed as well as the medical or surgical procedures used.

Every year, 3.5 million Europeans contract an infection while in hospital and 2.5 million die or are seriously debilitated as a result. In the United States, the Centers for Disease Control and Prevention estimated roughly 1.7 million hospital-associated infections, from all types of microorganisms, inclu­ding bacteria and fungi combined, cause or contribute to 99,000 deaths each year. In Europe, where hospital surveys have been conducted, the category of gram-negative infections are estimated to account for two-thirds of the 25,000 deaths each year. Nosocomial infections can cause severe pneumonia and in­fec­tions of the urinary tract, bloodstream and other parts of the body. Many types dis­play antimicrobial resistance, which can complicate treatment.

Modern healthcare employs many types of invasive devices and procedures to treat patients and to help them recover. Infections can be associated with the devices used in medical procedures, such as catheters or ventilators.  These healthcare-associated infections (HAIs) include central line-associated bloodstream infections, catheter-associated urinary tract infections, and ventilator-associated pneumonia. Infections may also occur at surgery sites, known as surgical site infections.


Below are types of HAI

  • Hospital-acquired pneumonia
  • Ventilator-associated pneumonia
  • Urinary tract infection
  • Gastroenteritis
  • Puerperal fever
  • Central line-associated blood stream infection


Below are the microorganisms which cause HAI

  • Staphylococcus aureus
  • Methicillin resistant Staphylococcus aureus
  • Candida albicans
  • Pseudomonas aeruginosa
  • Acinetobacter baumannii
  • Stenotrophomonas maltophilia
  • Clostridium difficile
  • Escherichia coli
  • Tuberculosis
  • Vancomycin-resistant Enterococcus
  • Legionnaires' disease


In-dwelling catheters have recently been identified with hospital acquired infections. To deal with this complication procedures are used, called intravascular antimicrobial lock therapy that can reduce infections that are unexposed to blood-borne antibiotics. Introducing antibiotics, including ethanol, into the catheter (without flushing it into the bloodstream) reduces the formation of biofilms.

The prevention of hospital-acquired infection depends on the continuous and concerted efforts of all those who design, administer, and work in hospitals. Microbiologists - whose training and experience should have made them familiar with the causes of communicable disease and the sources and routes of transmission of pathogenic micro-organisms - should play a leading part in these activities. Their traditional role in hospitals has been to examine specimens from individual patients for the purpose of identifying the microbial cause of diseases and to give advice about appropriate chemotherapy in the light of their findings. To function effectively in the preventive field, however, their activities must be extended in several directions.






By Aliyev F.