Hospital-acquired infection
A hospital-acquired infection, also known as a nosocomial infection (from the Greek nosokomeion, meaning "hospital"), is an infection that is acquired in a hospital or other healthcare facility.[1] To emphasize both hospital and nonhospital settings, it is sometimes instead called a healthcare-associated infection.[2] Such an infection can be acquired in a hospital, nursing home, rehabilitation facility, outpatient clinic, diagnostic laboratory or other clinical settings. A number of dynamic processes can bring contamination into operating rooms and other areas within nosocomial settings. [3][4] Infection is spread to the susceptible patient in the clinical setting by various means. Healthcare 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. In some cases the microorganism originates from the patient's own skin microbiota, becoming opportunistic after surgery or other procedures that compromise the protective skin barrier. Though the patient may have contracted the infection from their own skin, the infection is still considered nosocomial since it develops in the health care setting.[5] Nosocomial infection tends to lack evidence that it was present when the patient entered the healthcare setting, thus meaning it was acquired post-admission.[5][6]
Nosocomial infection
HAI (Healthcare-Associated Infections)
Effects[edit]
During 2002 in the United States, the Centers for Disease Control and Prevention estimated that roughly 1.7 million healthcare-associated infections, from all types of microorganisms, including bacteria and fungi combined, caused or contributed to 99,000 deaths.[7] 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.[8] Nosocomial infections can cause severe pneumonia and infections of the urinary tract, bloodstream and other parts of the body.[9][10] Many types display antimicrobial resistance, which can complicate treatment.[11]
In the UK about 300,000 patients were affected in 2017, and this was estimated to cost the NHS about £1 billion a year.[12]
Cause[edit]
Transmission[edit]
In-dwelling catheters have recently been identified with hospital-acquired infections.[14] To deal with this complication, procedures are used, called intravascular antimicrobial lock therapy, that can reduce infections that are unexposed to blood-borne antibiotics.[15] Introducing antibiotics, including ethanol, into the catheter (without flushing it into the bloodstream) reduces the formation of biofilms.[13]
Treatment[edit]
Two of the bacteria species most likely to infect patients are the Gram-positive strains of methicillin-resistant Staphylococcus aureus, and Gram-negative Acinetobacter baumannii. While antibiotic drugs to treat diseases caused by methicillin-resistant Staphylococcus aureus are available, few effective drugs are available for Acinetobacter. Acinetobacter bacteria are evolving and becoming immune to antibiotics, so in many cases, polymyxin-type antibacterials need to be used. "In many respects it's far worse than MRSA", said a specialist at Case Western Reserve University.[47]
Another growing disease, especially prevalent in New York City hospitals, is the drug-resistant, Gram-negative Klebsiella pneumoniae. An estimated more than 20% of the Klebsiella infections in Brooklyn hospitals "are now resistant to virtually all modern antibiotics, and those supergerms are now spreading worldwide."[47]
The bacteria, classified as Gram-negative because of their color on the Gram stain, can cause severe pneumonia and infections of the urinary tract, bloodstream, and other parts of the body. Their cell structures make them more difficult to attack with antibiotics than Gram-positive organisms like methicillin-resistant Staphylococcus aureus. In some cases, antibiotic resistance is spreading to Gram-negative bacteria that can infect people outside the hospital. "For gram-positives we need better drugs; for gram-negatives we need any drugs", said Brad Spellberg, an infectious-disease specialist at Harbor–UCLA Medical Center, and the author of Rising Plague, a book about drug-resistant pathogens.[47]
Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection and accounts for approximately one-fourth of all infections in the intensive care unit (ICU).[48] HAP, or nosocomial pneumonia, is a lower respiratory infection that was not incubating at the time of hospital admission and that presents clinically two or more days after hospitalization.[49] Ventilator-associated pneumonia (VAP) is defined as HAP in patients receiving mechanical ventilation. The incidence of VAP is 10–30% among patients who require mechanical ventilation for >48 h.[50] A standard treatment protocol is based on accurate diagnosis definitions, microbiological confirmation of VAP, and the administration of imipenem plus ciprofloxacin as initial empirical antibiotic treatment.[51]
One-third of nosocomial infections are considered preventable. The CDC estimates 687,000 people in the United States were infected by hospital-acquired infections in 2015, resulting in 72,000 deaths.[52] The most common nosocomial infections are of the urinary tract, surgical site and various pneumonias.[7]
An alternative treatment targeting localised infections is the use of irradiation by ultraviolet C.[53]
