Nosocomial infection


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Nosocomial infection

  1. 1. Nosocomial infection Nosocomial infection Classification and external resources Contaminated surfaces increase cross-transmission ICD-10 Y95 Look up nosocomial in Wiktionary, the free dictionary.A nosocomial infection (nos-oh-koh-mi-al), also known as a hospital-acquired infection orHAI, is an infection whose development is favoured by a hospital environment, such as oneacquired by a patient during a hospital visit or one developing among hospital staff. Suchinfections include fungal and bacterial infections and are aggravated by the reduced resistanceof individual patients.[1]In the United States, the Centers for Disease Control and Prevention estimate that roughly 1.7million hospital-associated infections, from all types of microorganisms, including bacteria,combined, cause or contribute to 99,000 deaths each year.[2] In Europe, where hospitalsurveys have been conducted, the category of Gram-negative infections are estimated toaccount for two-thirds of the 25,000 deaths each year. Nosocomial infections can cause severepneumonia and infections of the urinary tract, bloodstream and other parts of the body. Manytypes are difficult to attack with antibiotics, and antibiotic resistance is spreading to Gram-negative bacteria that can infect people outside the hospital.[2]Known nosocomial infections Ventilator associated pneumonia (VAP) Staphylococcus aureus Methicillin resistant Staphylococcus aureus (MRSA)
  2. 2. Candida albicans Pseudomonas aeruginosa Acinetobacter baumannii Stenotrophomonas maltophilia Clostridium difficile Tuberculosis Urinary tract infection Hospital-acquired pneumonia (HAP) Gastroenteritis Vancomycin-resistant Enterococcus (VRE) Legionnaires diseaseEpidemiology This paragraph needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2012)Nosocomial infections are commonly transmitted when hospital officials become complacentand personnel do not practice correct hygiene regularly. Also, increased use of outpatienttreatment means that people who are hospitalized are more ill[clarification needed] and have moreweakened immune systems[clarification needed] than may have been true in the past. Moreover,some medical procedures bypass the bodys natural protective barriers. Since medical staffmove from patient to patient, the staff themselves serve as a means for spreading pathogens.Essentially, the staff act as vectors.Categories and treatmentAmong 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 antibioticdrugs that can treat diseases caused by Gram-positive MRSA, there are currently feweffective drugs for Acinetobacter. However, Acinetobacter germs are evolving and becomingimmune to existing antibiotics. "In many respects it‟s far worse than MRSA," said a specialistat Case Western Reserve University.[2]Another growing disease, especially prevalent in New York City hospitals, is the drug-resistant Gram-negative germ, Klebsiella pneumoniae. An estimated more than 20 percent ofthe Klebsiella infections in Brooklyn hospitals "are now resistant to virtually all modernantibiotics. And those supergerms are now spreading worldwide."[2]The bacteria, classified as Gram-negative because of their reaction to the Gram stain test, cancause severe pneumonia and infections of the urinary tract, bloodstream, and other parts of thebody. 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 needbetter 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 bookabout drug-resistant pathogens.[2]
  3. 3. One-third of nosocomial infections are considered preventable. The CDC estimates 2 millionpeople in the United States are infected annually by hospital-acquired infections, resulting in20,000 deaths.[3] The most common nosocomial infections are of the urinary tract, surgicalsite and various pneumonias.[4]Country estimatesThe methods used differ from country to country (definitions used, type of nosocomialinfections covered, health units surveyed, inclusion or exclusion of imported infections, etc.),so that international comparisons of nosocomial infection rates should be made with theutmost care.United States: The Centers for Disease Control and Prevention (CDC) estimates that roughly1.7 million hospital-associated infections, from all types of bacteria combined, cause orcontribute to 99,000 deaths each year.[2] 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.In the USA the most frequent type of infection hospitalwide is urinary tract infection (36%),followed by surgical site infection (20%), bloodstream infection (BSI), and pneumonia (both11%).[2]France: estimates ranged from 6.7% in 1990 to 7.4% (patients may have severalinfections).[5] At national level, prevalence among patients in health care facilities was 6.7%in 1996,[6] 5.9% in 2001[7] and 5.0% in 2006.[8] 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%).[9] The rates among adult patients in intensive care were 13,5% in 2004, 14,6% in2005, 14,1% in 2006 and 14.4% in 2007.[10]It has also been estimated that nosocomial infections make patients stay in the hospital 4-5additional days. Around 2004-2005, about 9,000 people died each year with a nosocomialinfection, of which about 4,200 would have survived without this infection.[11]Italy: since 2000, estimates show that about 6.7% infection rate, i.e. between 450,000 and700,000 patients, which caused between 4,500 and 7,000 deaths.[12] A survey in Lombardygave a rate of 4.9% of patients in 2000.[13]United Kingdom: estimates of 10% infection rate,[14] with 8.2% estimated in 2006.[15]Switzerland: estimates range between 2 and 14%.[16] A national survey gave a rate of 7.2% in2004.[17]Finland: estimated at 8.5% of patients in 2005[18]Transmission
  4. 4. The drug-resistant Gram-negative germs for the most part threaten only hospitalized patientswhose immune systems are weak. The germs can survive for a long time on surfaces in thehospital and enter the body through wounds, catheters, and ventilators.[2] Main routes of transmission Route DescriptionContact the most important and frequent mode of transmission of nosocomialtransmission infections. occurs when droplets are generated from the source person mainly during coughing, sneezing, and talking, and during the performance of certainDroplet procedures such as bronchoscopy. Transmission occurs when dropletstransmission containing germs from the infected person are propelled a short distance through the air and deposited on the hosts body. 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 thisAirborne manner can be dispersed widely by air currents and may become inhaled by atransmission 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 applies to microorganisms transmitted to the host by contaminated itemsvehicle such as food, water, medications, devices, and equipment.transmissionVector borne occurs when vectors such as mosquitoes, flies, rats, and other vermintransmission transmit microorganisms.Contact transmission is divided into two subgroups: direct-contact transmission and indirect-contact transmission. Routes of contact transmission Route Description 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, orDirect-contact performs other patient-care activities that require direct personal contact.transmission 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. involves contact of a susceptible host with a contaminated intermediate object, usually inanimate, such as contaminated instruments, needles, orIndirect-contact dressings, or contaminated gloves that are not changed between patients. Intransmission 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.[19]
  5. 5. Risk factorsFactors 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.PreventionHospitals have sanitation protocols regarding uniforms, equipment sterilization, washing, andother preventative measures. Thorough hand washing and/or use of alcohol rubs by allmedical personnel before and after each patient contact is one of the most effective ways tocombat nosocomial infections.[20] More careful use of antimicrobial agents, such asantibiotics, is also considered vital.[21]Despite sanitation protocol, patients cannot be entirely isolated from infectious agents.Furthermore, patients are often prescribed antibiotics and other antimicrobial drugs to helptreat illness; this may increase the selection pressure for the emergence of resistant strains.SterilizationSterilization goes further than just sanitizing. Sterilizing kills all microorganisms onequipment and surfaces through exposure to chemicals, ionizing radiation, dry heat, or steamunder pressure.IsolationIsolation precautions are designed to prevent transmission of microorganisms by commonroutes in hospitals. Because agent and host factors are more difficult to control, interruption oftransfer of microorganisms is directed primarily at transmission.Handwashing and glovingHandwashing frequently is called the single most important measure to reduce the risks oftransmitting skin microorganisms from one person to another or from one site to another onthe same patient. Washing hands as promptly and thoroughly as possible between patientcontacts and after contact with blood, body fluids, secretions, excretions, and equipment orarticles contaminated by them is an important component of infection control and isolation
  6. 6. precautions. The spread of nosocomial infections, among immunocompromised patients isconnected with Health Care Workers hand contamination in almost 40% of cases and it is areal challenging problem in the modern hospitals. The best way for Health Care Workers toovercome this problem is acting right hand hygiene procedures, this is why the WHOlaunched in 2005 the GLOBAL Patient Safety Challenge.[22] Two categories of microorganisms can be present on Health Care Workers hands: transient flora and resident flora.The first one is represented by the micro organisms taken by Health Care Workers from theenvironment, and the bacteria in it are capable of surviving on the human skin and sometimesto grow. The second group on the other hand, is represented by the permanent microorganisms that lived on the skin surface (on the stratum corneum or immediately under it).They are capable of surviving on the human skin and to grow freely on it. They have lowpathogenicity and infection rate, and they create a kind of protection from the colonizationfrom other more pathogenic bacteria. The skin of Health Care Workers is colonized by 3.9 x104 – 4.6 x 106 cfu / cm2. The micro organisms creating the resident flora are:Staphylococcus epidermidis, Staphylococcus hominis, Microccoci, Propionibacterium,Corynebacterium, Dermobacterium, Pitosporum, while in the transitional could be foundStaphylococcus aureus, Klebsiella pneumoniae, Acinetobacter spp, Enterobacter spp andCandida spp. The goal of hand hygiene is to eliminate the transient flora with a careful andproper performance of hand wash, using different kind of soap, from the normal one to theantiseptic, and alcohol based gel. The main problems found in the practice of hand hygiene isconnected 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 rub, because ofits faster application compared to a correct hand washing.[23]Although handwashing may seem like a simple process, it is often performed incorrectly.Healthcare settings must continuously remind practitioners and visitors on the properprocedure in washing their hands to comply with responsible handwashing. Simple programssuch as Henry the Hand, and the use of handwashing signals can assist healthcare facilities inthe prevention of nosocomial infections.All visitors must follow the same procedures as hospital staff to adequately control the spreadof infections. Visitors and healthcare personnel are equally to blame in transmittinginfections.[citation needed] Moreover, multidrug-resistant infections can leave the hospital andbecome part of the community flora if steps are not taken to stop this transmission.In addition to handwashing, gloves play an important role in reducing the risks oftransmission 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 thehands when touching blood, body fluids, secretions, excretions, mucous membranes, andnonintact skin. In the USA, the Occupational Safety and Health Administration has mandatedwearing gloves to reduce the risk of bloodborne pathogen infection.[24] Second, gloves areworn to reduce the likelihood that microorganisms present on the hands of personnel will betransmitted to patients during invasive or other patient-care procedures that involve touching apatients mucous membranes and nonintact skin. Third, gloves are worn to reduce thelikelihood that hands of personnel contaminated with microorganisms from a patient or afomite can transmit these microorganisms to another patient. In this situation, gloves must bechanged 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
  7. 7. removal of gloves. Failure to change gloves between patient contacts is an infection controlhazard.Surface sanitationSanitizing surfaces is an often overlooked, yet crucial component of breaking the cycle ofinfection in health care environments. Modern sanitizing methods such as NAV-CO2 havebeen effective against gastroenteritis, MRSA, and influenza. Use of hydrogen peroxide vaporhas been clinically proven to reduce infection rates and risk of acquisition. Hydrogen peroxideis effective against endospore-forming bacteria, such as Clostridium difficile, where alcoholhas been shown to be ineffective.[25]Antimicrobial surfacesMicroorganisms are known to survive on inanimate „touch‟ surfaces for extended periods oftime.[26] This can be especially troublesome in hospital environments where patients withimmunodeficiencies are at enhanced risk for contracting nosocomial infections.Touch surfaces commonly found in hospital rooms, such as bed rails, call buttons, touchplates, chairs, door handles, light switches, grab rails, intravenous poles, dispensers (alcoholgel, paper towel, soap), dressing trolleys, and counter and table tops are known to becontaminated with Staphylococcus, Methicillin-resistant Staphylococcus aureus (MRSA), oneof the most virulent strains of antibiotic-resistant bacteria and Vancomycin-resistantEnterococcus (VRE).[27] Objects in closest proximity to patients have the highest levels ofstaphylococcus, MRSA, and VRE. This is why touch surfaces in hospital rooms can serve assources, or reservoirs, for the spread of bacteria from the hands of healthcare workers andvisitors to patients.Main article: Antimicrobial copper touch surfacesMain article: Antimicrobial properties of copperCopper alloy surfaces have intrinsic properties to destroy a wide range of microorganisms. Inthe interest of protecting public health, especially in heathcare environments with theirsusceptible patient populations, an abundance of peer-reviewed antimicrobial efficacy studieshave been and continue to be conducted around the world regarding copper‟s efficacy todestroy E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA),Staphylococcus, Clostridium difficile, influenza A virus, adenovirus, and fungi.[28]Much of this antimicrobial efficacy work has been or is currently being conducted at theUniversity of Southampton and Northumbria University (United Kingdom), University ofStellenbosch (South Africa), Panjab University (India), University of Chile (Chile), KitasatoUniversity (Japan), the Instituto do Mar[29] and University of Coimbra (Portugal), and theUniversity of Nebraska and Arizona State University (U.S.A.). A summary of theantimicrobial copper touch surfaces clinical trials to date is available[30]In 2007, U.S. Department of Defense‟s Telemedicine and Advanced Technologies ResearchCenter (TATRC) began to study the antimicrobial properties of copper alloys in a multi-siteclinical hospital trial conducted at the Memorial Sloan-Kettering Cancer Center (New YorkCity), the Medical University of South Carolina, and the Ralph H. Johnson VA Medical
  8. 8. Center (South Carolina).[31] Commonly-touched items, such as bed rails, over-the-bed traytables, chair arms, nurses call buttons, IV poles, etc. were retrofitted with antimicrobialcopper alloys in certain patient rooms (i.e., the “coppered” rooms) in the Intensive Care Unit(ICU). Early results disclosed in 2011 indicate that the coppered rooms demonstrated a 97%reduction in surface pathogens versus the non-coppered rooms. This reduction is the samelevel achieved by “terminal” cleaning regimens conducted after patients vacate their rooms.Furthermore, of critical importance to health care professionals, the preliminary resultsindicated that patients in the coppered ICU rooms had a 40.4% lower risk of contracting ahospital acquired infection versus patients in non-coppered ICU rooms.[32][33][34] The U.S.Department of Defense investigation contract, which is ongoing, will also evaluate theeffectiveness of copper alloy touch surfaces to prevent the transfer of microbes to patients andthe transfer of microbes from patients to touch surfaces, as well as the potential efficacy ofcopper-alloy based components to improve indoor air quality.In the U.S., the Environmental Protection Agency regulates the registration of antimicrobialproducts. After extensive antimicrobial testing according to the Agency‟s stringent testprotocols, 355 copper alloys, including many brasses, were found to kill more than 99.9% ofmethicillin-resistant Staphylococcus aureus (MRSA), E. coli O157:H7, Pseudomonasaeruginosa, Staphylococcus aureus, Enterobacter aerogenes, and vancomycin-resistantEnterococci (VRE) within two hours of contact.[35][36] Normal tarnishing was found to notimpair antimicrobial effectiveness.On February 29, 2008, the United States Environmental Protection Agency (EPA) granted itsfirst registrations of five different groups of copper alloys as “antimicrobial materials” withpublic health benefits.[37] The registrations granted antimicrobial copper as "a supplement toand not a substitute for standard infection control practices." Subsequent registrationapprovals of additional copper alloys have been granted. The results of the EPA-supervisedantimicrobial studies, demonstrating coppers strong antimicrobial efficacies across a widerange of alloys, have been published.[38] These copper alloys are the only solid surfacematerials to be granted “antimicrobial public health claims” status by EPA.The EPA registrations state that laboratory testing has shown that when cleaned regularly: Antimicrobial Copper Alloys continuously reduce bacterial contamination, achieving 99.9% reduction within two hours of exposure. Antimicrobial Copper Alloy surfaces kill greater than 99.9% of Gram-negative and Gram- positive bacteria within two hours of exposure. Antimicrobial Copper Alloy surfaces deliver continuous and ongoing antibacterial action, remaining effective in killing greater than 99% of bacteria within two hours. Antimicrobial Copper Alloys surfaces kill greater than 99.9% of bacteria within two hours, and continue to kill 99% of bacteria even after repeated contamination. Antimicrobial Copper Alloys surfaces help inhibit the buildup and growth of bacteria within two hours of exposure between routine cleaning and sanitizing steps. Testing demonstrates effective antibacterial activity against Staphylococcus aureus, Enterobacter aerogenes, Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli O157:H7, and Pseudomonas aeruginosaThe registrations state that “antimicrobial copper alloys may be used in hospitals, otherhealthcare facilities, and various public, commercial and residential buildings.” A list ofantimicrobial copper products approved by the EPA is available.[39]
  9. 9. ApronsWearing an apron during patient care reduces the risk of infection.[citation needed] The apronshould either be disposable or be used only when caring for a specific patient. MitigationThe most effective technique of controlling nosocomial infection is to strategically implementQA/QC measures to the health care sectors and evidence-based management can be a feasibleapproach. For those VAP/HAP diseases (ventilator-associated pneumonia, hospital-acquiredpneumonia), controlling and monitoring hospital indoor air quality needs to be on agenda inmanagement[40] whereas for nosocomial rotavirus infection, a hand hygiene protocol has to beenforced.[41][42][43] Other areas that the management needs to be covered include ambulancetransport.[citation needed]