A hospital-acquired infection or nosocomial infection is an infection whose development
is favored by a hospital environment, such as one acquired by a patient during a hospital
visit or one developing among hospital staff.
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,
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 are difficult to attack with antibiotics, and antibiotic resistance is spreading to
Gram-negative bacteria that can infect people outside the hospital.
HAI is sometimes expanded as healthcare-associated infection to emphasize that infections can
be correlated with health care in various settings.
Types
Cause Nosocomial infections are commonly transmitted
when hospital officials become complacent and personnel do not practice correct hygiene
regularly.
Also, increased use of outpatient treatment in recent decades means that a greater percentage
of people who are hospitalized today are likely to be seriously ill with more weakened immune
systems than 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.
Essentially, the staff act as vectors.
Transmission The drug-resistant Gram-negative bacteria,
for the most part, threaten only hospitalized patients whose immune systems are weak.
They can survive for a long time on surfaces in the hospital and enter the body through
wounds, catheters, and ventilators.
Contact transmission is divided into two subgroups: direct-contact transmission and indirect-contact
transmission.
Prevention The most effective technique for 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 with ventilator-associated or hospital-acquired pneumonia, controlling and monitoring hospital
indoor air quality needs to be on agenda in management, whereas for nosocomial rotavirus
infection, a hand hygiene protocol has to be enforced.
Other areas needing management include ambulance transport.
To reduce HAIs, the state of Maryland implemented the Maryland Hospital-Acquired Conditions
Program that provides financial rewards and penalties for individual hospitals based on
their ability to avoid HAIs.
An adaptation of the Centers for Medicare & Medicaid Services payment policy causes
poor-performing hospitals to lose up to 3% of their inpatient revenues, whereas hospitals
that are able to avoid HAIs can earn up to 3% in rewards.
During the program’s first 2 years, complication rates fell by 15.26 percent across all hospital-acquired
conditions tracked by the state, from a risk-adjusted complication rate of 2.38 per 1,000 people
in 2009 to a rate of 2.02 in 2011.
The 15.26-percent decline translates into more than $100 million in cost savings for
the health care system in Maryland, with the largest savings coming from avoidance of urinary
tract infections, septicemia and other severe infections, and pneumonia and other lung infections.
If similar results could be achieved nationwide, the Medicare program would save an estimated
$1.3 billion over 2 years, whereas the health care system as a whole would save $5.3 billion.
Hospitals have sanitation protocols regarding uniforms, equipment sterilization, washing,
and other preventive 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.
More careful use of antimicrobial agents, such as antibiotics, is also considered vital.
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.
Sterilization Sterilization goes further than just sanitizing.
It kills all microorganisms on equipment and surfaces through exposure to chemicals, ionizing
radiation, dry heat, or steam under pressure.
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 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.
The spread of nosocomial infections, among immunocompromised patients is connected with
health care workers' hand contamination in almost 40% of cases, and is a challenging
problem in the modern hospitals.
The best way for workers to overcome this problem is conducting correct hand-hygiene
procedures; this is why the WHO launched in 2005 the GLOBAL Patient Safety Challenge.
Two categories of micro-organisms can be present on health care workers' hands: transient flora
and resident flora.
The first is represented by the micro-organisms taken by workers from the environment, and
the bacteria in it are capable of surviving on the human skin and sometimes to grow.
The second group is represented by the permanent micro-organisms living on the skin surface.
They are capable of surviving on the human skin and to grow freely on it.
They have low pathogenicity and infection rate, and they create a kind of protection
from the colonization from other more pathogenic bacteria.
The skin of workers is colonized by 3.9 x 104 – 4.6 x 106 cfu/cm2.
The microbes comprising the resident flora are: Staphylococcus epidermidis, S. hominis,
and Microccocus, Propionibacterium, Corynebacterium, Dermobacterium, and Pitosporum spp., while
in the transitional could be found S. aureus, and Klebsiella pneumoniae, and Acinetobacter,
Enterobacter and Candida spp.
The goal of hand hygiene is to eliminate the transient flora with a careful and proper
performance of hand washing, using different kinds of soap,, and alcohol-based gels.
The main problems found in the practice of hand hygiene is connected with the lack of
available sinks and time-consuming performance of hand washing.
An easy way to resolve this problem could be the use of alcohol-based hand rubs, because
of faster application compared to correct hand washing.
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 steps are not taken to stop this transmission.
It is unclear as of 2014 if nail polish or rings affected surgical would infection rates
as it has not been studied.
Gloves 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, they 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 infections.
Second, gloves are worn to reduce the likelihood 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, they are worn to reduce the likelihood the hands of personnel contaminated with micro-organisms
from a patient or a fomite can be transmitted 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,
inapparent 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 crucial, 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 agents.
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.
Ultraviolet cleaning devices may also be used to disinfect the rooms of patients infected
with Clostridium difficile after discharge.
Antimicrobial surfaces Micro-organisms are known to survive on inanimate
‘touch’ surfaces for extended periods of time.
This can be especially troublesome in hospital environments where patients with immunodeficiencies
are at enhanced risk for contracting nosocomial infections.
Touch surfaces commonly found in hospital rooms, such as bed rails, call buttons, touch
plates, chairs, door handles, light switches, grab rails, intravenous poles, dispensers,
dressing trolleys, and counter and table tops are known to be contaminated with Staphylococcus,
MRSA and vancomycin-resistant Enterococcus.
Objects in closest proximity to patients have the highest levels of MRSA and VRE.
This is why touch surfaces in hospital rooms can serve as sources, or reservoirs, for the
spread of bacteria from the hands of healthcare workers and visitors to patients.
A number of compounds can decrease the risk of bacteria growing on surfaces including:
copper, silver, and germicides.
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.
Treatment Among the categories of bacteria most known
to infect patients are the category MRSA, member of Gram-positive bacteria and Acinetobacter,
which is Gram-negative.
While antibiotic drugs to treat diseases caused by Gram-positive MRSA are available, few effective
drugs are available for Acinetobacter.
Acinetobacter bacteria are evolving and becoming immune to existing 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.
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.
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 structures make 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.
One-third of nosocomial infections are considered preventable.
The CDC estimates 2 million people in the United States are infected annually by hospital-acquired
infections, resulting in 20,000 deaths.
The most common nosocomial infections are of the urinary tract, surgical site and various
pneumonias.
Epidemiology The methods used differ from country to country,
so the international comparisons of nosocomial infection rates should be made with the utmost
care.
United States The Centers for Disease Control and Prevention
estimated roughly 1.7 million hospital-associated infections, from all types of bacteria combined,
cause or contribute to 99,000 deaths each year.
Other estimates indicate 10%, or 2 million, patients a year become infected, with the
annual cost ranging from $4.5 billion to $11 billion.
In the USA, the most frequent type of infection hospitalwide is urinary tract infection, followed
by surgical site infection, and bloodstream infection and pneumonia.
France Estimates ranged from 6.7% in 1990 to 7.4%.
At national level, prevalence among patients in health care facilities was 6.7% in 1996,
5.9% in 2001 and 5.0% in 2006.
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, pneumopathy, infections
of surgery site.
Infections of the skin and mucous membrane, other respiratory infections and bacterial
infections / blood poisoning.
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.
Nosocomial infections are estimated to make patients stay in the hospital four to five
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.
Italy Since 2000, estimates show about a 6.7% infection
rate, i.e. between 450,000 and 700,000 patients, which caused between 4,500 and 7,000 deaths.
A survey in Lombardy gave a rate of 4.9% of patients in 2000.
United Kingdom Estimates show a 10% infection rate, with
8.2% estimated in 2006.
Switzerland Estimates range between 2 and 14%.
A national survey gave a rate of 7.2% in 2004.
Finland Rate were estimated at 8.5% of patients in
2005.
Belgium In Belgium the prevalence of nosocomial infections
is about 6.2%.
Annually about 125 500 patients become infected by a nosocomial infection, resulting in almost
3000 deaths.
The extra costs for the health insurance are estimated to be approximately €400 million/year.
See also Cubicle curtain
Infection control Iatrogenesis
NAV-CO2 Phototherapy
Sanitation Standard Operating Procedures References