Posted on 24th Sep 2024 06:25:39 PM Medicine
Introduction
A nosocomial infection also called "hospital acquired infection" can be defined as: An infection acquired in hospital by a patient who was admitted for a reason other than that infection (Ducel; 1995). An infection occurring in a patient in a hospital or other health care facility in whom the infection was not present or incubating at the time of admission. This includes infections acquired in the hospital but appearing after discharge, and also occupational infections among staff of the facility (Benenson;1995). Patient care is provided in facilities which range from highly equipped clinics and technologically advanced university hospitals to front-line units with only basic facilities. Despite progress in public health and hospital care, infections continue to develop in hospitalized patients, and may also affect hospital staff. Many factors promote infection among hospitalized patients: decreased immunity among patients; the increasing variety of medical procedures and invasive techniques creating potential routes of infection; and the transmission of drug-resistant bacteria among crowded hospital populations, where poor infection control practices may facilitate transmission.
1.1 Frequency of infection
Nosocomial infections occur worldwide and affect both developed and resource-poor countries. Infections acquired in health care settings are among the major causes of death and increased morbidity among hospitalized patients. They are a significant burden both for the patient and for public health. A prevalence survey conducted under the auspices of WHO in 55 hospitals of 14 countries representing 4 WHO Regions (Europe, Eastern Mediterranean, South-East Asia and Western Pacific) showed an average of 8.7% of hospital patients had nosocomial infections. At any time, over 1.4 million people worldwide suffer from infectious complications acquired in hospital (Tikhomirov;1987). The highest frequencies of nosocomial infections were reported from hospitals in the Eastern Mediterranean and South-East Asia Regions (11.8 and 10.0% respectively), with a prevalence of 7.7 and 9.0% respectively in the European and Western Pacific Regions (Mayon-White;1991). The most frequent nosocomial infections are infections of surgical wounds, urinary tract infections and lower respiratory tract infections. The WHO study, and others, have also shown that the highest prevalence of nosocomial infections occurs in intensive care units and in acute surgical and orthopaedic wards. Infection rates are higher among patients with increased susceptibility because of old age, underlying disease, or chemotherapy.
1.2 Impact of nosocomial infections
Hospital-acquired infections add to functional disability and emotional stress of the patient and may, in some cases, lead to disabling conditions that reduce the quality of life. Nosocomial infections are also one of the leading causes of death (Ponce-de-Leon;1991). The economic costs are considerable (Plowman,1999; Wenzel,1995). The increased length of stay for infected patients is the greatest contributor to cost (Pittet , Taraara , Wenzel,1994; Kirkland et al,1999; Wakefield et al.,1988). One study (Wakefiel et al.,1993) showed that the overall increase in the duration of hospitalization for patients with surgical wound infections was 8.2 days, ranging from 3 days for gynaecology to 9.9 for general surgery and 19.8 for orthopaedic surgery. Prolonged stay not only increases direct costs to patients or payers but also indirect costs due to lost work. The increased use of drugs, the need for isolation, and the use of additional laboratory and other diagnostic studies also contribute to costs. Hospital-acquired infections add to the imbalance between resource allocation for primary and secondary health care by diverting scarce funds to the management of potentially preventable conditions. The advancing age of patients admitted to health care settings, the greater prevalence of chronic diseases among admitted patients, and the increased use of diagnostic and therapeutic procedures which affect the host defences will provide continuing pressure on nosocomial infections in the future.
Organisms causing nosocomial infections can be transmitted to the community through discharged patients, staff, and visitors. If organisms are multiresistant, they may cause significant disease in the community.
1.3 Factors influencing the development of nosocomial infections
1.3.1 The microbial agent
The patient is exposed to a variety of microorganisms during hospitalization. Contact between thepatient and a microorganism does not by itself necessarily result in the development of clinical disease — other factors influence the nature and frequency of nosocomial infections. The likelihood of exposure leading to infection depends partly on the characteristicsn of the microorganisms, including resistance to antimicrobial agents, intrinsic virulence, and amount (inoculum) of infective material. Many different bacteria, viruses, fungi and parasites may cause nosocomial infections. Infections may be caused by a microorganism acquired from another person in the hospital (cross infection) or may be caused by the patient’s own flora (endogenous infection). Some organisms may be acquired from an inanimate object or substances recently contaminated from another human source (environmental infection). Before the introduction of basic hygienic practices and antibiotics into medical practice, most hospital infections were due to pathogens of external origin (foodborne and airborne diseases, gas gangrene, tetanus, etc.) or were caused by microorganisms not present in the normal flora of the patients (e.g. diphtheria, tuberculosis). Progress in the antibiotic treatment of bacterial infections has considerably reduced mortality from many infectious diseases. Most infections acquired in hospital today are caused by microorganisms which are common in the general population, in whom they cause no or milder disease than among hospital patients (Staphylococcus aureus, coagulase-negative staphylococci, enterococci, Enterobacteriaceae).
1.3.2 Patient susceptibility
Important patient factors influencing acquisition of infection include age, immune status, underlying disease, and diagnostic and therapeutic interventions. The extremes of life — infancy and old age — are associated with a decreased resistance to infection. Patients with chronic disease such as malignant tumours, leukaemia, diabetes mellitus, renal failure, or the acquired immunodeficiency syndrome (AIDS) have an increased susceptibility to infections with opportunistic pathogens. The latter are infections with organism(s) that are normally innocuous, e.g. part of the normal bacterial flora in the human, but may become pathogenic when the body’s immunological defences are compromised. Immunosuppressive drugs or irradiation may lower resistance to infection. Injuries to skin or mucous membranes bypass natural defence mechanisms. Malnutrition is also a risk. Many modern diagnostic and therapeutic procedures, such as biopsies, endoscopic examinations, catheterization, intubation/ventilation and suction and surgical procedures increase the risk of infection. Contaminated objects or substances may be introduced directly into tissues or normally sterile sites such as the urinary tract and the lower respiratory tract.
1.3.3 Environmental factors
Health care settings are an environment where both infected persons and persons at increased risk of infection congregate. Patients with infections or carriers of pathogenic microorganisms admitted tohospital are potential sources of infection for patients and staff. Patients who become infected in the hospital are a further source of infection. Crowded conditions within the hospital, frequent transfers of patients from one unit to another, and concentration of patients highly susceptible to infection in one area (e.g. newborn infants, burn patients, intensive care) all contribute to the development of nosocomial infections. Microbial flora may contaminateobjects, devices, and materials which subsequently contact susceptible body sites of patients. In addition, new infections associated with bacteria such as waterborne bacteria (atypical mycobacteria) and/or viruses and parasites continue to be identified.
1.3.4 Bacterial resistance
Many patients receive antimicrobial drugs. Through selection and exchange of genetic resistance elements, antibiotics promote the emergence of multidrugresistant strains of bacteria; microorganisms in the normal human flora sensitive to the given drug are suppressed, while resistant strains persist and may become endemic in the hospital. The widespread use of antimicrobials for therapy or prophylaxis (including topical) is the major determinant of resistance. Antimicrobial agents are, in some cases, becoming less effective because of resistance. As an antimicrobial agent becomes widely used, bacteria resistant to this drug eventually emerge and may spread in the health care setting. Many strains of pneumococci, staphylococci, enterococci, and tuberculosis are currently resistant to most or all antimicrobials which were once effective. Multiresistant Klebsiella and Pseudomonas aeruginosa are prevalent in many hospitals. This problem is particularly critical in developing countries where more expensive second-line antibiotics may not be available or affordable (Atlanta& Georgia,1990).
Nosocomial infections are widespread. They are important contributors to morbidity and mortality. They will become even more important as a public health problem with increasing economic and human impact because of:
· Increasing numbers and crowding of people.
· More frequent impaired immunity (age, illness, treatments).
· New microorganisms.
· Increasing bacterial resistance to antibiotics (Ducel, 1995).
2. Types of nosocomial infections
Like any infectious condition, nosocomial infections can be bacterial, viral, fungal, or even parasitic. The most common pathogens include staphylococci (especially staphylococcus aureus), pseudomonas, and Escherichia coli. However, various newer pathogens are becoming more important. Fungal conditions, mainly from candida, comprise approximately 9% of nosocomial infections.
2.1 Fungal nosocomial infections
Several fungi have become more common in nosocomial infections with a rate reported as 3.8 per 1,000 hospital patients (CDC/NNIS). The most common are Candida (mostly Candida albicans), Aspergillus, Fusarium, Trichosporon, and Malassezia. Candidiasis remains the most common type of nosocomial fungal infection, particularly in the immunocompromised. Risk factors for fungal infections include antibiotic treatments, chemotherapy, intravascular catheters, neutropenia, hemodialysis, or prior fungal infection.
2.2 Antibiotic resistance
Many of the pathogens that cause nosocomial infections have a high level of resistance to antibiotic treatments. These emerging pathogens are the most serious concerns, because they are more difficult to treat. Some of the major concerns are methicillin resistant staphylococcus aureus (MRSA), vancomycin-resistant Staphylococcus aureus, and vancomycin-resistant enterococci (VRE).
2.3 Nosocomial Urinary tract infections
Urinary tract infections are the most common nosocomial infections. These infections can be caused by various pathogens such as E. coli, Pseudomonas, or Enterococcus.
2.4 Nosocomial pneumonia
Pneumonia is a common and serious nosocomial infection in the USA. Pneumonia is the second most common nosocomial infection in the United States. Most patients affected are have risk factors such as: mechanical ventilation (high risk), elderly, neonates, severe underlying disease, immunodeficiency, depressed sensorium, cardiopulmonary disease, or recent thoraco-abdominal surgery. Several types of pathogens can infect the respiratory tract and cause nosocomial pneumonia: bacterial pneumonia, Legionnaires' disease, pulmonary aspergillosis, Mycobacterium tuberculosis, and viral pneumonias such as Respiratory Syncytial Virus (RSV) and influenza.
3. Microorganisms
Many different pathogens may cause nosocomial infections. The infecting organisms vary among different patient populations, different health care settings, different facilities, and different countries. Bacteria These are the most common nosocomial pathogens. A distinction may be made between: _ Commensal bacteria found in normal flora of healthy humans. These have a significant protective role by preventing colonization by pathogenic microorganisms. Some commensal bacteria may cause infection if the natural host is compromised. For example, cutaneous coagulasenegative staphylococci cause intravascular line infection and intestinal Escherichia coli are the most common cause of urinary infection. _ Pathogenic bacteria have greater virulence, and cause infections (sporadic or epidemic) regardless of host status. For example: — Anaerobic Gram-positive rods (e.g. Clostridium) cause gangrene. — Gram-positive bacteria: Staphylococcus aureus (cutaneous bacteria that colonize the skin and nose of both hospital staff and patients) cause a wide variety of lung, bone, heart and bloodstream infections and are frequently resistant to antibiotics; beta-haemolytic streptococci are also important. — Gram-negative bacteria: Enterobacteriacae (e.g. Escherichia coli, Proteus, Klebsiella, Enterobacter, Serratia marcescens), may colonize sites when the host defences are compromised (catheter insertion, bladder catheter, cannula insertion) and cause serious infections (surgical site, lung, bacteraemia, peritoneum infection). They may also be highly resistant. — Gram-negative organisms such as Pseudomonas spp. are often isolated in water and damp areas. They may colonize the digestive tract of hospitalized patients. — Selected other bacteria are a unique risk in hospitals. For instance, Legionella species may cause pneumonia (sporadic or endemic) through inhalation of aerosols containing contaminated water (air conditioning, showers, therapeutic aerosols).
3.1 Viruses
There is the possibility of nosocomial transmission of many viruses, including the hepatitis B and C viruses (transfusions, dialysis, injections, endoscopy), respiratory syncytial virus (RSV), rotavirus, and enteroviruses (transmitted by hand-to-mouth contact and via the faecal-oral route). Other viruses such as cytomegalovirus, HIV, Ebola, influenza viruses, herpes simplex virus, and varicella-zoster virus, may also be transmitted.
3.2 Parasites and fungi
Some parasites (e.g. Giardia lamblia) are transmitted easily among adults or children. Many fungi and other parasites are opportunistic organisms and cause infections during extended antibiotic treatment and severe immunosuppression (Candida albicans, Aspergillus spp., Cryptococcus neoformans, Cryptosporidium).
These are a major cause of systemic infections among immunocompromised patients. Environmental contamination by airborne organisms such as Aspergillus spp. which originate in dust and soil is also a concern, especially during hospital construction. Sarcoptes scabies (scabies) is an ectoparasite which has repeatedly caused outbreaks in health care facilities.
4. Modes of Transmission
The principal avenues of transmission of hospital-acquired infections are contact, droplet, airborne and common-vehicle.
Contact transmission is the most common and most preventable means of transmission. Contact transmission can be divided into direct and indirect contact.
· Direct contact involves body surface to body surface contact with a physical transfer of microorganisms.
· Indirect contact (cross-contamination) involves body surface contact with a contaminated intermediate object.
· Washing and drying hands can help reduce transmission via common contact surfaces.
Proper hand hygiene, before and after contact, eliminates or significantly reduces the possibility of infection transmission.
Droplet transmission occurs when droplets containing microorganisms from an infected person are propelled through the air and land on the mouth, eyes, or nose of another person. Droplets are generated primarily when a person is coughing, sneezing, or talking. Droplets do not remain suspended in the air and should not be confused with airborne transmissions.
Airborne transmission results when a droplet containing microorganisms evaporates and remains suspended in the air for a long time. Airborne transmission also occurs with dust particles containing infectious agents. If working in close contact (3 feet or less), cover nose, mouth and eyes, if possible.
Common vehicle transmission refers to contaminated items such as food, water, medications, devices, and equipment.
5. Controlling infection
Spread of infection can be controlled and reduced by:
· Strict hospital infection control procedures and policies
· Correct and frequent hand washing by all hospital staff and patients
· Cautious use of antibiotic medication.
5.1 Reduction of risk of nosocomial infections
If you are going to hospital, there are things you can do before admission and in hospital that will help reduce the chance of you getting an infection.
Before admission follow these steps before you go to hospital:
· Stop smoking - smoking can interfere with healing processes. It also damages the airways, which can make lung infections more likely.
· Maintain a healthy weight - people who are overweight are more prone to infection.
· Inform your doctor of all existing or recent illness - a cold or the flu can lead to a chest infection, so let your doctor or the hospital staff know if you are not well.
· Manage diabetes - if you are a diabetic, make sure that your blood sugar levels are under control.
5.2 During stay
Some things that can help reduce the chance of infection while you are in hospital include:
· Make sure that you wash your hands properly, especially after using the toilet. Remind hospital staff to do the same before and after they attend to you.
· Let your nurse know if the site around the needle is not clean and dry if you have an IV drip.
· Tell your nurse if the dressings are not clean, dry and attached around any wounds you may have.
· Let your nurse know if tubes or catheters feel displaced.
· Do your deep breathing exercises - the staff will instruct you. This is very important because they can help prevent a chest infection.
· Ask relatives or friends who have colds or are unwell not to visit.
5.3 What to expect if get an infection
If you do acquire an infection in hospital, other procedures and practices (apart from antibiotic treatment) may be put in place to stop the spread of infection to other patients. Depending on the type of infection, these might include:
· Isolation in a single room
· Being put last on the operation surgery list
· Being nursed by staff wearing gloves and gowns.
5.4 Where to get help
· Hospital infection control department
· Nursing staff
· Doctor
5.5 Things to remember
· There are things you can do before and during your stay in hospital that will help reduce the chance of you getting an infection.
· Common types of hospital-acquired infections are chest infections, wound infections, urinary infections and bloodstream infections.
· Some people are more susceptible to hospital infections than others.
6. Risk factors of Hospital infections
6.1 Infections due to the community and the patients
· Illness to the patient
· Longer stay in hospital
· Longer recovery time
· Costs associated with a longer stay in hospital and longer recovery time.
6.2 More risk people than others
· Very young people - premature babies and very sick children
· Very old people - the frail and the elderly
· Those with medical conditions - such as diabetes
· People with defective immunity - people with diseases that compromise their immune system or people who are being treated with chemotherapy or steroids.
6.3 Other risk factors that may increase acquiring HAI
· Length of stay - a long hospital stay can increase the risk: for example, admission for complex or multiple illnesses.
· Operations and surgical procedures - the length and type of surgery can also impact.
· Hand washing techniques - inadequate hand washing by hospital staff and patients may increase your risk.
· Antibiotics - overuse of antibiotics can lead to resistant bacteria, which means that antibiotics become less effective.
· Equipment - invasive procedures can introduce infection into the body: for example, procedures that require the use of equipment such as urinary catheters, IV drips and infusions, respiratory equipment and drain tubes.
· Wounds - wounds, incisions (surgical cuts), burns and ulcers are all prone to infection.
6.4 High-risk areas
Some areas of the hospital are more likely to have infection, such as intensive care units (ICU) and high dependency units (HDU).
7. Prevention of nosocomial infections
Prevention of nosocomial infections requires an integrated, monitored, programme which includes the following key components: limiting transmission of organisms between patients in direct patient care through
· Adequate handwashing and glove use, and appropriate aseptic practice , isolation strategies, sterilization and disinfection practices, and laundry.
· Controlling environmental risks for infection.
· Protecting patients with appropriate use of prophylactic antimicrobials, nutrition, and vaccinations.
· Limiting the risk of endogenous infections by minimizing invasive procedures, and promoting optimal antimicrobial use.
· Surveillance of infections, identifying and controlling outbreaks.
· Prevention of infection in staff members.
· Enhancing staff patient care practices, and continuing staff education.
Infection control is the responsibility of all health care professionals — doctors, nurses, therapists, pharmacists, engineers and others.
7.1 Risk stratification (Underwood & Pirwitz,1998).
Acquisition of nosocomial infection is determined by both patient factors, such as degree of immunocompromise, and interventions performed which increase risk. The level of patient care practice may differ for patient groups at different risk of acquisition of infection. A risk assessment will be helpful to categorize patients and plan infection control interventions.
7.2 Reducing person-to-person transmission
The importance of hands in the transmission of hospital infections has been well demonstrated (Larson,1988), and can be minimized with appropriate hand hygiene (Larson,1995; Health Canada,1998). Compliance with handwashing, however, is frequently suboptimal. This is due to a variety of reasons, including: lack of appropriate accessible equipment, high staff-to-patient ratios, allergies to handwashing products, insufficient knowledge of staff about risks and procedures, too long a duration recommended for washing, and the time required.
7.3 Personal hygiene
All staff must maintain good personal hygiene. Nails must be clean and kept short. False nails should not be worn. Hair must be worn short or pinned up. Beard and moustaches must be kept trimmed short and clean.
7.3.1 Clothing
Staff can normally wear a personal uniform or street clothes covered by a white coat. In special areas such as burn or intensive care units, uniform trousers and a short-sleeved gown are required for men and women. In other units, women may wear a shortsleeved dress. The working outfit must be made of a material easy to wash and decontaminate. If possible, a clean outfit should be worn each day. An outfit must be changed after exposure to blood or if it becomes wet through excessive sweating or other fluid exposure.
Shoes: In aseptic units and in operating rooms, staff must wear dedicated shoes, which must be easy to clean.
Caps: In aseptic units, operating rooms, or performing selected invasive procedures, staff must wear caps or hoods which completely cover the hair.
Masks (Pratt et al., 2001): for filtration are an effective barrier against microorganisms.
· Masks are used in various situations; mask requirements differ for different purposes.
· Patient protection: staff wears masks to work in the operating room, to care for immuno-compromised patients, to puncture body cavities. A surgical mask is sufficient.
· Staff protection: staff must wear masks when caring for patients with airborne infections, or when performing bronchoscopies or similar examination. A high-efficiency mask is recommended.
· Patients with infections which may be transmitted by the airborne route must use surgical masks when outside their isolation room.
Gloves (Pratt et al., 2001): Gloves are used for:
· Patient protection: staff wear sterile gloves for surgery, care for immunocompromised patients, invasive procedures which enter body cavities.
· Non-sterile gloves should be worn for all patient contacts where hands are likely to be contaminated, or for any mucous membrane contact.
· Staff wears non-sterile gloves to care for patients with communicable disease transmitted by contact, to perform bronchoscopies or similar examinations.
· Hands must be washed when gloves are removed or changed.
· Disposable gloves should not be reused.
· Latex or polyvinyl-chloride are the materials most frequently used for gloves.
7.3.2 Safe injection practices
To prevent transmission of infections between patients with injections:
· Eliminate unnecessary injections.
· Use sterile needle and syringe.
· Use disposable needle and syringes, if possible.
· Prevent contamination of medications.
7.3.3 Preventing transmission from the environment
To minimize the transmission of microorganisms from equipment and the environment, adequate methods for cleaning, disinfecting and sterilizing must be in place. Written policies and procedures which are updated on a regular basis must be developed for each facility.
7.3.3.1 Cleaning of the hospital environment (Health Canada,1998; Pratt et al.,2001; Ducel et al.,1979)
· Routine cleaning is necessary to ensure a hospital environment which is visibly clean, and free from dust and soil.
· Ninety per cent of microorganisms are present within “visible dirt”, and the purpose of routine cleaning is to eliminate this dirt. Neither soap nor detergents have antimicrobial activity, and the cleaning process depends essentially on mechanical action.
· There must be policies specifying the frequency of cleaning and cleaning agents used for walls, floors, windows, beds, curtains, screens, fixtures, furniture, baths and toilets, and all reused medical devices.
· Methods must be appropriate for the likelihood of contamination, and necessary level of asepsis.
7.3.3.2 Use of hot/superheated water
An alternative to disinfection for environmental cleaning for some objects is hot water. Disinfection with hot water-
Temperature Duration
1. Sanitary equipment 80 0C 45–60 seconds
2. Cooking utensils 80 0C 1 minute
3. Linen 70 0C 25 minutes
95 0C 10 minutes
7.3.3.3 Disinfection of patient equipment
Disinfection removes microorganisms without complete sterilization to prevent transmission of organisms between patients. Disinfection procedures must (Health Canada, 1998; Association of Operating Room Nurses,1994; Rutala,1996): These levels of disinfection are attained by using the appropriate chemical product in the manner appropriate for the desired level of disinfection.
7.4 Prevention of common endemic nosocomial infections
The four most common nosocomial infections are urinary tract infections, surgical wound infections, pneumonia, and primary bloodstream infection. Each of these is associated with an invasive medical device or invasive procedure. Specific policies and practices to minimize these infections must be established, reviewed and updated regularly,
7.4.1 Urinary tract infections (UTI)
Urinary tract infections are the most frequent nosocomial infections (Kunin,1997); 80% of these infections are associated with an indwelling urethral catheter . Interventions effective in preventing nosocomial urinary infection include (Pratt et al.,2001; Falkiner,1993):
· Avoiding urethral catheterization unless there is a compelling indicationlimiting the duration of drainage, if catheterization is necessary
· Maintaining appropriate aseptic practice during urinary catheter insertion and other invasive urological procedures (e.g. cystoscopy, urodynamic testing, cystography)
· Hygienic handwash or rub prior to insertion and following catheter or drainage bag manipulation
· Sterile gloves for insertion
· Perineal cleaning with an antiseptic solution prior to insertion
· Non-traumatic urethral insertion using an appropriate lubricant
· Maintaining a closed drainage system. Other practices which are recommended, but not proven to decrease infection include:
· Maintaining good patient hydration
· Appropriate perineal hygiene for patients with
· Catheters
· Appropriate staff training in catheter insertion andcare maintaining unobstructed drainage of the bladder to the collection bag, with the bag below the level of the bladder.
Generally, the smallest diameter catheter should be used. Catheter material (latex, silicone) does not influence infection rates.
7.4.2 Surgical wound infections (surgical site infections)
Factors which influence the frequency of surgical wound infection include (Mangram et al.,1999; Cruse & Ford,1980; Pittet & Ducel,1994; Garibaldi et al.,1988):
· Surgical technique
· Extent of endogenous contamination of the wound at surgery (e.g. clean, clean-contaminated)
· Duration of operation
· Underlying patient status
· Operating room environment
· Organisms shed by the operating room team.
· Operating room environment
· Operating room staff
· Handwashing
· Operating room attire
· Operating room activitiy
· Pre-intervention preparation of the patient
· Antimicrobial prophylaxis
· Surgical wound surveillance
7.4.3 Nosocomial respiratory infections ( Tablan et al.,1994)
· Ventilator-associated pneumonia in the intensive care unit
· Medical units, surgical units
· Neurological patients with tracheostomy (with or without ventilation)
7.4.4 Infections associated with intravascular lines
· Peripheral vascular catheters
· Central vascular catheters
· Central vascular totally implanted catheters
8. Environment
The discussion of the environment will include building features, ventilation, water, food and wastes. Housekeeping and equipment.
8.1 Buildings
Health services — including public and private hospital services — must meet quality standards (ISO 9000 and ISO 14000 series) . It is recognized that older facilities, and facilities in developing countries, may not be able to achieve these standards. However, the principles underlying these standards should be kept in mind for local planning and, where possible, renovations should attempt to achieve standards.
· Planning for construction or renovation (Limacher,American Institute of Architects,2001)
· Architectural segregation
· Traffic flow (Ducel,1993)
· Materials
8.2 Air
8.2.1 Airborne contamination and transmission
Infection may be transmitted over short distances by large droplets, and at longer distances by droplet nuclei generated by coughing and sneezing (Knight,1973). Droplet nuclei remain airborne for long periods, may disseminate widely in an environment such as a hospital ward or an operating room, and can be acquired by (and infect) patients directly, or indirectly through contaminated medical devices. Housekeeping activity such as sweeping, using dry dust mops or cloths, or shaking out linen, can aerosolize particles that may contain microorganisms. Similarly, Legionella pneumophila, the organism responsible for legionellosis (Legionnaires’ disease; Pontiac fever), can become airborne during the evaporation of water droplets from air conditioning cooling towers or with aerosolization in patient showers, and subsequently may be inhaled by patients at risk of infection. The number of organisms present in room air will depend on the number of people occupying the room, the amount of activity, and the rate of air exchange. Bacteria recovered from air samples usually consist of Gram-positive cocci originating from the skin. They can reach large numbers if dispersed from an infected lesion, particularly an infected exfoliative skin lesion. However, since the contaminated skin scales are relatively heavy, they do not remain suspended in the air for long. Gram-negative bacteria are usually found in the air only when associated with aerosols from contaminated fluids, and tend to die on drying. Droplets projected from the infected upper respiratory tract may contain a wide variety of microrganisms, including viruses, and many infections can be spread by this route (i.e. respiratory viruses, influenza, measles, chickenpox, tuberculosis). In most cases, these are spread by large droplets, and an infective dose will rarely move more than a few feet from the source patient. Varicella-zoster (chickenpox), tuberculosis, and a few other agents, however, may be transmitted over large distances in droplet nuclei.
8.2.2 Ventilation
Fresh filtered air, appropriately circulated, will dilute and remove airborne bacterial contamination. It also eliminates smells. Desirable ventilation rates, expressed in air changes per hour, vary with the purpose of a particular area (Guide Uniclima). High-risk hospital areas (operating rooms, nurseries, intensive care units, oncology, and burn units) should have air with minimal bacterial contamination.
8.2.3 Operating theatres
Modern operating rooms which meet current air standards are virtually free of particles larger than 0.5 nm (including bacteria) when no people are in the room. Activity of operating room personnel is the main source of airborne bacteria, which originate primarily from the skin of individuals in the room. The number of airborne bacteria depends on number of factors. Conventional operating rooms are ventilated with 20 to 25 changes per hour of high-efficiency filtered air delivered in a vertical flow. High-efficiency particulate air (HEPA) systems remove bacteria larger than 0.5 to 5 nm in diameter and are used to obtain downstream bacteria-free air. The operating room is usually under positive pressure relative to the surrounding corridors, to minimize inflow of air into the room.
8.2.4 Ultra-clean air
For minimizing airborne particles, air must be circulated into the room with a velocity of at least 0.25 m/sec through a high-efficiency particulate air (HEPA) filter, which excludes particulate matter of defined size. If particles 0.3 microns in diameter and larger are removed, the air entering the room will be essentially clean and free of bacterial contaminants.
8.3 Water
The physical, chemical and bacteriological characteristics of water used in health care institutions must meet local regulations. The institution is responsible for the quality of water once it enters the building. For specific uses, water taken from a public network must often be treated for medical use (physical or chemical treatment). Criteria for drinkingwater are usually not adequate for medical uses of water.
8.3.1 Drinking-water
Drinking-water should be safe for oral ingestion. National norms and international recommendations define appropriate criteria for clean drinking-water. Unless adequate treatment is provided, faecal contamination may be sufficient to cause infection through food preparation, washing, the general care of patients, and even through steam or aerosol inhalation (Legionella pneumophila). Even water that conforms to accepted criteria may carry potentially pathogenic microorganisms. Organisms present in tap water have frequently been implicated in nosocomial infections
8.3.2 Baths
Baths can be used either for hygiene (patients, babies) or for specific purposes of care (burns, rehabilitation in swimming pools, lithotripsy). The main infectious agent in baths is Pseudomonas aeruginosa (Pollack,1995). It may cause folliculitis (generally benign), external otitis, which can become severe under certain conditions (diabetes, immunosuppression), and wound infections. Baths can also transmit other pathogens (Legionella, atypical mycobacteria — with swimming pool granuloma, enterobacteria such as Citrobacter freundii). Viral infections may also be transmitted in communal baths (Molluscum contagiosum, papillomavirus) through contact with contaminated surfaces. Parasitic infections such as cryptosporidiosis, giardiasis, and amoebiasis, and mycoses, especially Candida, may also be transmitted.
8.3.3 Pharmaceutical (medical) water
There are physical, chemical, bacteriological, and biological parameters which must be met for water used for medical purposes.
8.3.4 Microbiological monitoring
Regulations for water analysis (at the national level for drinking-water, in the Pharmacopoeia for pharmaceutical waters) define criteria, levels of impurities, and techniques for monitoring. For water use for which regulations are not available, parameters should be appropriate for the planned use and therequirements of users (including risk factors for patients). Methods used for monitoring must suit the use. Bacteriological, medical and biochemical methods are not necessarily adapted to environmental analyses, and may lead to falsely reassuring conclusions.
8.4 Food
Quality and quantity of food are key factors for patient convalescence. Ensuring safe food is an important service delivery in health care.
8.4.1 Agents of food poisoning and food borne infections
Bacterial food poisoning (acute gastroenteritis) is an infection or intoxication manifested by abdominal pain and diarrhoea, with or without vomiting or fever. The onset of symptoms may range from less than one to more than 48 hours after eating contaminated food. Usually, large numbers of organisms actively growing in food are required to initiate symptoms of infection or intoxication. Water, milk, and solid foods are all vehicles for transmission.
8.4.2 Factors contributing to food poisoning
The frequency of foodborne illness is increasing. This may be due to increasing complexity in modern food handling, particularly in mass-catering, as well as increasing importation of potentially contaminated food products from other countries. For individuals to develop food poisoning, the number of organisms in food must be of a sufficient level. There must also be adequate nutrients, moisture, and warmth for multiplication of organisms, or toxin production to occur between preparation and consumption of the food. Many inappropriate food handling practices permit contamination, survival and growth of infecting bacteria.
8.4.3 Prevention of food poisoning
Hospital policy, and rigorously adhered to maintain a clean work area, Separate raw and cooked food to avoid crosscontamination, use appropriate cooking techniques and follow recommendations to prevent growth of microorganisms in food.
8.5 Handling, storage and transportation of health care waste
All waste disposal practices must meet local regulations. The following practices are recommended as a general guide for safety and economic reasons, health care institutions, must organize a selective collection ofhospital waste, differentiating between medical, waste, general waste and some specific wastes, (sharp instruments, highly infectious waste, cytoxic waste). General health care waste may be disposed in the stream of domestic refuse.
9. Preventing infections of staff
Health care workers are at risk of acquiring infection through occupational exposure (CDC,1998&1996). Hospital employees can also transmit infections to patients and other employees. Thus, a programme must be in place to prevent and manage infections in hospital staff. Employees’ health should be reviewed at recruitment, including immunization history and previous exposures to communicable diseases (e.g. tuberculosis) and immune status. Some previous infections (e.g. varicella-zoster virus may be assessed by serological tests.
Immunizations recommended for staff include: hepatitis A and B, yearly influenza, measles, mumps, rubella, tetanus, diphtheria. Immunization against varicella may be considered in specific cases.
The Mantoux skin test will document a previous tuberculosis infection and must be obtained as a baseline. Specific postexposure policies must be developed, and compliance ensured for: human immunodeficiency virus (HIV), hepatitis A virus, hepatitis B virus, hepatitis C virus, Neisseria meningitidis, Mycobacterium tuberculosis, varicella-zoster virus, hepatitis E virus, Corynebacterium diphtheriae, Bordetella pertussis, and rabies.
10. General objectives
Assessment of nurse’s knowledge and practice to prevent and control regarding nosocomial infections in general ward at Rajshahi Medical College Hospital (RMCH).
10.1 Specific objectives
- To assess the nurse’s knowledge a practice regarding nosocomial infections.
- To assess the nurse’s knowledge about the spread of the nosocomial infections.
- To assess the nurse’s knowledge about the risk factors of the nosocomial infections.
- To assess the nurse’s knowledge & practice about the prevention and control of the nosocomial infections.
CONTENTS
Abstract
CHAPTER 1: INTRODUCTION
1.1 Frequency of infection
1.2 Impact of nosocomial infections
1.3 Factors influencing the development of nosocomial infections
2 Types of nosocomial infections
2.1 Fungal nosocomial infections
2.2 Antibiotic resistance
2.3 Nosocomial Urinary tract infections
2.4 Nosocomial pneumonia
3 Microorganisms
3.1 Viruses
3.2 Parasites and fungi
4 Modes of Transmission
5 Controlling infection
5.1 Reduction of risk of nosocomial infections
5.2 During stay
5.3 What to expect if get an infection
5.4 Where to get help
5.5 Things to remember
6 Risk factors of Hospital infections
6.1 Infections due to the community and the patients
6.2 More risk people than others
6.3 Other risk factors that may increase acquiring HAI
6.4 High-risk areas
7 Prevention of nosocomial infections
7.1 Risk stratification
7.2 Reducing person-to-person transmission
7.3 Personal hygiene
7.4 Prevention of common endemic nosocomial infections
8 Environment
8.1 Buildings
8.2 Air
8.3 Water
8.4 Food
8.5 Handling, storage and transportation of health care waste
9 Preventing infections of staff
10 General objectives
10.1 Specific objectives
CHAPTER 2: REVIEW OF LITERATURE
1.1 Nosocomial Infections: An overview
1.2 Nosocomial infection surveillance and control in human healthcare
CHAPTER 3: MATERIALS AND METHODS
1.1 Design of the study
1.2 Setting, population and sample
1.3 Instrumentation
1.4 Data collection procedure
CHAPTER 4: RESULTS
1.1 Demographic information on nurses
1.2 Knowledge & Practice related question to the nurse
CHAPTER 5: DISCUSSIONS
CHAPTER 6: CONCLUSION
CHAPTER 7: REFERENCES
CHAPTER 8: APPENDIX
Appendix I
Appendix II
Appendix III
LIST OF TABLES
Table-1 Demographic information for nurses
Table-2 Knowledge and practice related question for nurses
Table-2.1 Significant difference knowledge of the respondent
Table-2.2 Significant difference practice of the respondent
LIST OF FIGURES
Figure-1 Significant difference knowledge of the respondent
Figure-2 Significant difference practice of the respondent
Thesis, Assessment, Nurses, Knowledge, Practice, Prevent, Control, Regarding, Nosocomial, Infection, General, Ward, Rajshahi, Nursing, College, Medical, Hospital, RMCH
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