Nosocomial infection

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Nosocomial infection
Classification and external resources
ICD-10 Y95.

Nosocomial infections (pronounced /ˌnɔ.sə.ˈkɜʊ.mi.əl/, nos-uh-KOH-mee-uhl), are infections that are a result of treatment in a hospital or a healthcare service unit. Infections are considered nosocomial if they first appear 48 hours or more after hospital admission or within 30 days after discharge.[citation needed] Nosocomial comes from the Greek word nosokomeion (νοσοκομείον) meaning hospital (nosos = disease, komeo = to take care of). This type of infection is also known as a hospital-acquired infection (or, in generic terms, healthcare-associated infection).

In the United States, the Centers for Disease Control and Prevention estimates that roughly 1.7 million hospital-associated infections, from all types of bacteria combined, cause or contribute to 99,000 deaths each year.[1] 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 are difficult to attack with antibiotics, and antibiotic resistance is spreading to Gram-negative bacteria that can infect people outside the hospital.[1]

Nosocomial infections are commonly transmitted when hospital officials become complacent and personnel do not practice correct hygiene regularly. Also, increased use of outpatient treatment means that people who are hospitalized are more ill and have more weakened immune systems than may have been true in the past. Moreover, some medical procedures bypass the body's natural protective barriers. Since medical staff move from patient to patient, the staff themselves serve as a means for spreading pathogens.

Hospitals have sanitation protocols regarding uniforms, equipment sterilization, washing, and other preventative measures. Thorough hand washing and/or use of alcohol rubs by all medical personnel before and after each patient contact is one of the most effective ways to combat nosocomial infections.[2] More careful use of antimicrobial agents, such as antibiotics, is also considered vital.[3]

Despite sanitation protocol, patients cannot be entirely isolated from infectious agents. Furthermore, patients are often prescribed antibiotics and other antimicrobial drugs to help treat illness; this may increase the selection pressure for the emergence of resistant strains.

Epidemiology

Categories and treatment

Among the categories of bacteria most known to infect patients are the category MRSA, Gram-positive bacteria and Helicobacter, which is Gram-negative. While there are antibiotic drugs that can treat diseases caused by Gram-positive MRSA, there are currently few effective drugs for Acinetobacter. However, Acinetobacter germs are evolving and becoming immune to existing antibiotics. "In many respects it’s far worse than MRSA," said a specialist at Case Western Reserve University.[1]

Another growing disease, especially prevalent in New York City hospitals, is the drug-resistant Gram-negative germ, Klebsiella pneumoniae. It is estimated that more than 20 percent of the Klebsiella infections in Brooklyn hospitals "are now resistant to virtually all modern antibiotics. And those supergerms are now spreading worldwide."[1]

The bacteria, classified as Gram-negative because of their reaction to the Gram stain test, can cause severe pneumonia and infections of the urinary tract, bloodstream, and other parts of the body. Their cell structure makes them more difficult to attack with antibiotics than Gram-positive organisms like MRSA. 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 Dr. Brad Spellberg, an infectious-disease specialist at Harbor-UCLA Medical Center, and the author of Rising Plague, a book about drug-resistant pathogens.[1]

One-third of nosocomial infections are considered preventable. Ms. magazine reports that as many as 92 percent of deaths from hospital infections could be prevented.[4] The most common nosocomial infections are of the urinary tract, surgical site and various pneumonias.[5]

Country estimates

The methods used differ from country to country (definitions used, type of nosocomial infections covered, health units surveyed, inclusion or exclusion of imported infections, etc.), so that international comparisons of nosocomial infection rates should be made with the utmost care.

United States: The Centers for Disease Control and Prevention (CDC) estimates that roughly 1.7 million hospital-associated infections, from all types of bacteria combined, cause or contribute to 99,000 deaths each year.[1] Other estimates indicate that 10%, or 2 million, patients a year become infected, with the annual cost ranging from $4.5 billion to $11 billion.

France: estimates ranged from 6.7% in 1990 to 7.4% (patients may have several infections).[6] At national level, prevalence among patients in health care facilities was 6.7% in 1996,[7] 5.9% in 2001[8] and 5.0% in 2006.[9] The rates for nosocomial infections were 7.6% in 1996, 6.4% in 2001 and 5.4% in 2006.

In 2006, the most common infection sites were urinary tract infections (30,3 %), pneumopathy (14,7 %), infections of surgery site (14,2 %). infections of the skin and mucous membrane (10,2 %), other respiratory infections (6,8%) and bacterial infections / blood poisoning (6,4 %).[10] The rates among adult patients in intensive care were 13,5% in 2004, 14,6% in 2005, 14,1% in 2006 and 14.4% in 2007.[11]

It has also been estimated that nosocomial infections make patients stay in the hospital 4-5 additional days. Around 2004-2005, about 9,000 people died each year with a nosocomial infection, of which about 4,200 would have survived without this infection.[12]

Italy: since 2000, estimates show that about 6.7 % infection rate, i.e. between 450,000 and 700,000 patients, which caused between 4,500 and 7,000 deaths.[13] A survey in Lombardy gave a rate of 4.9% of patients in 2000.[14]

United Kingdom: estimates of 10% infection rate,[15] with 8.2% estimated in 2006.[16]

Switzerland: estimates range between 2 and 14%.[17] A national survey gave a rate of 7.2% in 2004.[18]

Finland: estimated at 8.5% of patients in 2005[19]

Transmission

The drug-resistant Gram-negative germs for the most part threaten only hospitalized patients whose immune systems are weak. The germs can survive for a long time on surfaces in the hospital and enter the body through wounds, catheters, and ventilators.[1]

Main routes of transmission
Route Description
Contact transmission the most important and frequent mode of transmission of nosocomial infections.
Droplet transmission occurs when droplets are generated from the source person mainly during coughing, sneezing, and talking, and during the performance of certain procedures such as bronchoscopy. Transmission occurs when droplets containing germs from the infected person are propelled a short distance through the air and deposited on the host's body.
Airborne transmission occurs by dissemination of either airborne droplet nuclei (small-particle residue {5 µm or smaller in size} of evaporated droplets containing microorganisms that remain suspended in the air for long periods of time) or dust particles containing the infectious agent. Microorganisms carried in this manner can be dispersed widely by air currents and may become inhaled by a susceptible host within the same room or over a longer distance from the source patient, depending on environmental factors; therefore, special air handling and ventilation are required to prevent airborne transmission. Microorganisms transmitted by airborne transmission include Legionella, Mycobacterium tuberculosis and the rubeola and varicella viruses.
Common vehicle transmission applies to microorganisms transmitted to the host by contaminated items such as food, water, medications, devices, and equipment.
Vector borne transmission occurs when vectors such as mosquitoes, flies, rats, and other vermin transmit microorganisms.

Contact transmission is divided into two subgroups: direct-contact transmission and indirect-contact transmission.

Routes of contact transmission
Route Description
Direct-contact transmission involves a direct body surface-to-body surface contact and physical transfer of microorganisms between a susceptible host and an infected or colonized person, such as occurs when a person turns a patient, gives a patient a bath, or performs other patient-care activities that require direct personal contact. Direct-contact transmission also can occur between two patients, with one serving as the source of the infectious microorganisms and the other as a susceptible host.
Indirect-contact transmission involves contact of a susceptible host with a contaminated intermediate object, usually inanimate, such as contaminated instruments, needles, or dressings, or contaminated gloves that are not changed between patients. In addition, the improper use of saline flush syringes, vials, and bags has been implicated in disease transmission in the US, even when healthcare workers had access to gloves, disposable needles, intravenous devices, and flushes.[20]

Risk factors

Factors predisposing a patient to infection can broadly be divided into three areas:

  • People in hospitals are usually already in a poor state of health, impairing their defense against bacteria – advanced age or premature birth along with immunodeficiency (due to drugs, illness, or irradiation) present a general risk, while other diseases can present specific risks - for instance, chronic obstructive pulmonary disease can increase chances of respiratory tract infection.
  • Invasive devices, for instance intubation tubes, catheters, surgical drains, and tracheostomy tubes all bypass the body’s natural lines of defence against pathogens and provide an easy route for infection. Patients already colonised on admission are instantly put at greater risk when they undergo an invasive procedure.
  • A patient’s treatment itself can leave them vulnerable to infection – immunosuppression and antacid treatment undermine the body’s defences, while antimicrobial therapy (removing competitive flora and only leaving resistant organisms) and recurrent blood transfusions have also been identified as risk factors.

Prevention

Isolation

Isolation precautions are designed to prevent transmission of microorganisms by common routes in hospitals. Because agent and host factors are more difficult to control, interruption of transfer of microorganisms is directed primarily at transmission.

Handwashing and gloving

Handwashing frequently is called the single most important measure to reduce the risks of transmitting skin microorganisms from one person to another or from one site to another on the same patient. Washing hands as promptly and thoroughly as possible between patient contacts and after contact with blood, body fluids, secretions, excretions, and equipment or articles contaminated by them is an important component of infection control and isolation precautions.

Although handwashing may seem like a simple process, it is often performed incorrectly. Healthcare settings must continuously remind practitioners and visitors on the proper procedure in washing their hands to comply with responsible handwashing. Simple programs such as Henry the Hand, and the use of handwashing signals can assist healthcare facilities in the prevention of nosocomial infections.

All visitors must follow the same procedures as hospital staff to adequately control the spread of infections. Visitors and healthcare personnel are equally to blame in transmitting infections. Moreover, multidrug-resistant infections can leave the hospital and become part of the community flora if we do not take steps to stop this transmission.

In addition to handwashing, gloves play an important role in reducing the risks of transmission of microorganisms. Gloves are worn for three important reasons in hospitals. First, gloves are worn to provide a protective barrier and to prevent gross contamination of the hands when touching blood, body fluids, secretions, excretions, mucous membranes, and nonintact skin. In the USA, the Occupational Safety and Health Administration has mandated wearing gloves to reduce the risk of bloodborne pathogen infecition.[21] Second, gloves are worn to reduce the likelihood that microorganisms present on the hands of personnel will be transmitted to patients during invasive or other patient-care procedures that involve touching a patient's mucous membranes and nonintact skin. Third, gloves are worn to reduce the likelihood that hands of personnel contaminated with microorganisms from a patient or a fomite can transmit these microorganisms to another patient. In this situation, gloves must be changed between patient contacts, and hands should be washed after gloves are removed.

Wearing gloves does not replace the need for handwashing, because gloves may have small, non-apparent defects or may be torn during use, and hands can become contaminated during removal of gloves. Failure to change gloves between patient contacts is an infection control hazard.

Surface sanitation

Sanitizing surfaces is an often overlooked, yet critical component of breaking the cycle of infection in health care environments. Modern sanitizing methods such as NAV-CO2 have been effective against gastroenteritis, MRSA, and influenza. Use of hydrogen peroxide vapor has been clinically proven to reduce infection rates and risk of acquisition. Hydrogen peroxide is effective against endospore-forming bacteria, such as Clostridium difficile, where alcohol has been shown to be ineffective.[22]

Aprons

Wearing an apron during patient care reduces the risk of infection.[citation needed] The apron should either be disposable or be used only when caring for a specific patient.

Mitigation

The most effective technique of controlling nosocomial infection is to strategically implement QA/QC measures to the health care sectors and evidence-based management can be a feasible approach. For those VAP/HAP diseases (ventilator-associated pneumonia, hospital-acquired pneumonia), controlling and monitoring hospital indoor air quality needs to be on agenda in management [23] whereas for nosocomial rotavirus infection, a hand hygiene protocol has to be enforced.[24][25][26] Other areas that the management needs to be covered include

Known diseases

See also

References

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Health science · Medicine · Medical specialities · Intensive care medicine / Critical care medicine and Critical care nursing
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External causes of morbidity and mortality (V-Y, E)
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Adverse drug reaction/
drug eruption
antibiotics: Penicillin drug reaction · Sulfonamide hypersensitivity syndrome · Urticarial erythema multiforme · Adverse effects of fluoroquinolones

hormones: Steroid acne · Steroid folliculitis

chemotherapy: Chemotherapy-induced acral erythema · Chemotherapy-induced hyperpigmentation · Scleroderma-like reaction to taxanes · Hydroxyurea dermopathy · Exudative hyponychial dermatitis

blood: Anticoagulant-induced skin necrosis · Warfarin necrosis · Vitamin K reaction · Texier's disease

anticonvulsant: Anticonvulsant hypersensitivity syndrome

water-balance/acid-base: Allopurinol hypersensitivity syndrome

pulmonary: Leukotriene receptor antagonist-associated Churg–Strauss syndrome

vaccine: Eczema vaccinatum

other specified agents: Adverse reaction to biologic agents · Adverse reaction to cytokines · Bromoderma · Halogenoderma · Iododerma · Red man syndrome · Methotrexate-induced papular eruption

unspecified agent: Acute generalized exanthematous pustulosis · Bullous drug reaction · Drug-induced acne · Drug-induced angioedema · Drug-related gingival hyperplasia · Drug-induced lichenoid reaction · Drug-induced lupus erythematosus · Drug-induced nail changes · Drug-induced pigmentation · Drug-induced pseudolymphoma · Drug-induced urticaria · Fixed drug reaction · Stevens–Johnson syndrome · Injection site reaction · Linear IgA bullous dermatosis · Toxic epidermal necrolysis · HIV disease-related drug reaction · Photosensitive drug reaction · Serum sickness-like reaction
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Ballistic trauma · Nosocomial infection
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zh:院內感染
  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Pollack, Andrew. "Rising Threat of Infections Unfazed by Antibiotics" New York Times, Feb. 27, 2010
  2. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  3. ↑ Lautenbach E (2001). "Chapter 14. Impact of Changes in Antibiotic Use Practices on Nosocomial Infections and Antimicrobial Resistance—Clostridium difficile and Vancomycin-resistant Enterococcus (VRE)". In Markowitz AJ. Making Health Care Safer: A Critical Analysis of Patient Safety Practices. Agency for Healthcare Research and Quality. 
  4. ↑ Ricks, Delthia (2007). "Germ Warfare". Ms. Magazine: 43–5. 
  5. ↑ Klevens RM, Edwards JR, Richards CL; et al. (2007). "Estimating health care-associated infections and deaths in U.S. hospitals, 2002". Public Health Rep. 122 (2): 160–6. PMC 1820440 Freely accessible. PMID 17357358. 
  6. ↑ Quenon JL, Gottot S, Duneton P, Lariven S, Carlet J, Régnier B, Brücker G. Enquête nationale de prévalence des infections nosocomiales en France : Hôpital Propre (octobre 1990). BEH n° 39/1993.
  7. ↑ Comité technique des infections nosocomiales (CTIN), Cellule infections nosocomiales, CClin Est, CClin Ouest, CClin Paris-Nord, CClin Sud-Est, CClin Sud-Ouest, avec la participation de 830 établissements de santé. Enquête nationale de prévalence des infections nosocomiales,1996, BEH n° 36/1997, 2 sept. 1997, 4 pp.. Résumé.
  8. ↑ Lepoutre A, Branger B, Garreau N, Boulétreau A, Ayzac L, Carbonne A, Maugat S, Gayet S, Hommel C, Parneix P, Tran B pour le Réseau d’alerte, d’investigation et de surveillance des infections nosocomiales (Raisin). Deuxième enquête nationale de prévalence des infections nosocomiales, France, 2001, Surveillance nationale des maladies infectieuses, 2001-2003. Institut de veille sanitaire, sept. 2005, 11 pp. Résumé.
  9. ↑ Institut de veille sanitaire Enquête nationale de prévalence des infections nosocomiales, France, juin 2006, Volume 1 – Méthodes, résultats, perspectives, mars 2009, ii + 81 pp. Volume 2 – Annexes, mars 2009, ii + 91 pp. Synthèse des résultats, Mars 2009, 11 pp.
  10. ↑ Ibid, Vol. 1, Tableau 31, p. 24.
  11. ↑ Réseau REA-Raisin « Surveillance des infections nosocomiales en réanimation adulte. France, résultats 2007 », Institut de veille sanitaire, Sept. 2009, ii + 60 pp.
  12. ↑ Vasselle, Alain « Rapport sur la politique de lutte contre les infections nosocomiales », Office parlementaire d'évaluation des politiques de santé, juin 2006, 290 pp. (III.5. Quelle est l’estimation de la mortalité attribuable aux IN ?).
  13. ↑ L'Italie scandalisée par "l'hôpital de l'horreur", Éric Jozsef, Libération, January 17, 2007
    français :
  14. ↑ Liziolia A, Privitera G, Alliata E, Antonietta Banfi EM, Boselli L, Panceri ML, Perna MC, Porretta AD, Santini MG, Carreri V. Prevalence of nosocomial infections in Italy: result from the Lombardy survey in 2000. J Hosp Infect 2003;54:141-8.
  15. ↑ Aodhán S Breathnacha, Nosocomial infections, Medicine, 2005: 33, 22-26
  16. ↑ Press release for The Third Prevalence Survey of Healthcare-associated Infections in Acute Hospitals. Hospital Infection Society, Londres, 27/10/06.
  17. ↑ Facts sheet - Swiss Hand Hygiene Campaign. (.doc)
  18. ↑ Sax H, Pittet D pour le comité de rédaction de Swiss-NOSO et le réseau Swiss-NOSO Surveillance. Résultats de l’enquête nationale de prévalence des infections nosocomiales de 2004 (snip04). Swiss-NOSO 2005;12(1):1-4.
  19. ↑ Lyytikainen O, Kanerva M, Agthe N, Mottonen T and the Finish Prevalence Survey Study Group. National Prevalence Survey on Nosocomial Infections in Finnish Acute Care Hospitals, 2005. 10th Epiet Scientific Seminar. Mahon, Menorca, Spain, 13–15 October 2005 [Poster].
  20. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  21. ↑ http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=16265&p_table=FEDERAL_REGISTER
  22. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  23. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  24. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  25. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  26. ↑ Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
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