Re: Nosocomial Infections

Nosocomial infection
From Wikipedia, the free encyclopedia


Nosocomial infections are infections which are a result of treatment
in a hospital or a healthcare service unit, but secondary to the
patient's original condition. Infections are considered nosocomial if
they first appear 48 hours or more after hospital admission or within
30 days after discharge. 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. The most common nosocomial infections are of the
urinary tract, and various pneumonias.

Nosocomial infections are even more alarming in the 21st century as
antibiotic resistance spreads. Reasons why nosocomial infections are
so common include:

Hospitals house large numbers of people who are sick and whose immune
systems are often in a weakened state;
Increased use of outpatient treatment means that people who are in the
hospital are sicker on average;
Medical staff move from patient to patient, providing a way for
pathogens to spread;
Many medical procedures bypass the body's natural protective
barriers;
Routine use of anti-microbial agents in hospitals creates selection
pressure for the emergence of resistant strains.[citation needed]
Thorough hand washing and/or use of alcohol rubs by all medical
personnel before each patient contact is one of the most effective
ways to combat nosocomial infections. More careful use of anti-
microbial agents, such as antibiotics, is also considered vital.
[citation needed]


[edit] Epidemiology
In the United States, it has been estimated that as many as one
hospital patient in ten acquires a nosocomial infection, or 2 million
patients a year. Estimates of the annual cost range from $4.5 billion
to $11 billion and up. Nosocomial infections contributed to 88,000
deaths in the U.S. in 1995. One third of nosocomial infections are
considered preventable. Ms. magazine reports that as many as 90
percent of deaths from hospital infections could be prevented. [1]

In France, the prevalence is 6.87%[2], to 7.5%[3] (some patients are
infected twice) :

Urinary tract infection: 40%;
infection of the skin and mucous membrane: 10.8%;
infections of surgery site: 10.3%;
pneumopathy: 10%.
A ratio of 5 to 19% hospitalized patients are infected, and up to 30%
in intensive care units. The patients must stay in the hospital 4-5
additional days. About 9,000 people die with a nosocomial infection,
but about 4,200 would have not died without this infection.

In Italy, in the 2000's, about 6.7 % of hospitalized patients were
infected, i.e. between 450,000 and 700,000 patients, which caused
between 4,500 and 7,000 deaths.[4]

In Switzerland, extrapolations assume about 70'000 hospitalised
patients are affected by nosocomial infections (between 2 and 14% of
hospitalized patients).[5] [6]


[edit] Transmission
Microorganisms are transmitted in hospitals by several routes, and the
same microorganism may be transmitted by more than one route. There
are five main routes of transmission -- contact, droplet, airborne,
common vehicle, and vectorborne.

Contact transmission, the most important and frequent mode of
transmission of nosocomial infections, is divided into two subgroups:
direct-contact transmission and indirect-contact transmission.
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. Additionally, the
improper use of saline flush syringes, vials, and bags have been
implicated in disease transmission in the US, even when healthcare
workers had access to gloves, disposable needles, intravenous devices,
and flushes.[7]
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 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.

[edit] Predisposition to infection
Factors predisposing a patient to infection can broadly be divided
into four 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 IR
radiation) 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.

[edit] Prevention

[edit] 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.


[edit] Handwashing and gloving
Handwashing frequently is called the single most important measure to
reduce the risks of transmitting 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 measure, it is often not
used or hand washing is performed incorrectly. Healthcare settings
must continually remind practitioners and visitors to wash their hands
thoroughly. Simple programs, for example - "Henry The Hand", can be
used to help healthcare facilities prevent nosocomial infections. All
visitors must follow the same procedures as hospital staff for
infections to be adequately controlled. Visitors and healthcare
personnel are equally important in transmitting infections. Moreover,
multi-drug resistant infections can leave the hospital and become part
of the community flora if we dont 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; the wearing of gloves in specified
circumstances to reduce the risk of exposures to bloodborne pathogens
is mandated by the OSHA Bloodborne Pathogens final rule. 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.

Examples of nosocomial infections include Methicillin Resistant
Staphylococcus aureus (MRSA) and Acinetobacter baumanni.


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


[edit] Birth
Proponents of home birth often cite the benefit of avoiding nosocomial
infection by avoiding hospital delivery.


[edit] Known diseases
Ventilator associated pneumonia
Staphylococcus aureus
Methicillin-resistant Staphylococcus aureus
HIV/AIDS
Pseudomonas aeruginosa
Acinetobacter baumannii
Stenotrophomonas maltophilia
Clostridium difficile
Tuberculosis
Urinary tract infection
Hospital-acquired pneumonia
Gastroenteritis

[edit] Mitigation
The most effective of controlling Nosocomial infection is to
strategically implementing QA / QC measures to the health care sectors
and evidence-based management can be a feasible approach. For those
VAP/HAP diseases, controlling and monitoring hospital indoor air
quality needs to be on agenda in management [8] whereas for Nosocomial
rotavirus infection, a hand hygiene protocol has to be enforced [9],
[10],[11].


[edit] References
^ Ricks, Delthia. "Germ Warfare." Ms. Magazine. Spring 2007. pp
43-45.
^ enquête nationale de prévalence 2001
^ Quelle est la prévalence de ces infections ?
^ L'Italie scandalisée par « l'hôpital de l'horreur », Éric Jozsef,
Libération, 15 janvier 2007
^ http://www.edi.admin.ch/dokumentation/00613/00614/?lang=de&msg-id=2532
^ http://www.swisshandhygiene.ch/swisshandhygiene/presse/_b/contentFiles/301006_Facts_sheet_F.doc
^ (July 2005) "Nosocomial malaria and saline flush". Emerging
Infectious Diseases [serial on the Internet] 11 (7). Centers for
Disease Control and Prevention.
^ Leung, Michael; Alan H. S. Chan (2006). "Control and management of
hospital indoor air quality <internet>".
^ Chan, Pei-Chun et al. (2007). "Control of an Outbreak of Pandrug-
Resistant Acinetobacter baumannii Colonization and Infection in a
Neonatal Intensive Care Unit <internet>".
^ Josie, L. et al. (2006). "Pilot study to evaluate 3 hygiene
protocols on the reduction of bacterial load on the hands of
veterinary staff performing routine equine physical examinations
<internet>".
^ Katz, Jonathan D. (2004). "Hand washing and hand disinfection: more
than your mother taught you <internet>".

[edit] See also
Iatrogenesis, a disease or complication caused by medical treatment
Infectious disease
Infection control
Sterilization (surgical procedure)
Cleanroom
Sporadic infection

External links
Abedon, Stephen T. (98-05-09). Nosocomial Infections: Supplemental
Lecture.
Retrieved from "http://en.wikipedia.org/wiki/Nosocomial_infection";

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