Nosocomial infections, hospital acquired infections, are an on-going concern to healthcare professionals. These infections are one of the major causes of death in hospitalised patients and are a significant burden on not only the patient’s and the public’s health (as organisms causing nosocomial infections can be transmitted to the community through discharged patients, staff and visitors) but also the economy. A nosocomial infection is an infection acquired at least 72 hours after being admitted into hospital for any reason other than the infection or one which develops amongst hospital staff.
Infections are also identified as nosocomial if they appear in a patient within 30 days after their discharge from hospital. Non nosocomial infections, community acquired infections, are infections acquired anywhere other than the hospital. The most common places where non nosocomial infections occur are schools, day care centres and sports facilities. They are spread through skin to skin contact, cuts and grazes, overcrowding and poor hygiene. The illnesses or infections can be the same, for example, pneumonia or gastroenteritis but it is the setting that they are contracted in which differentiate the two infections.
Nosocomial infections occur worldwide and affect both wealthy, developed countries as well as the poorer ones with scarce resources. A survey conducted by the World Health Organisation in 55 hospitals across Europe, the Eastern Mediterranean, South East Asia and the Western Pacific shows an average of 8. 7% of hospital patients have a nosocomial infection. At any one time, over 1. 4million people have a hospital acquired infection. According to a report published by The National Audit Office in the United Kingdom, there are at least 100,000 hospital acquired infections per year at a cost to the NHS of hundreds of millions of pounds.
The result of acquiring an infection could be an extended stay in hospital, increased use of drugs for further treatment as well as the possibility of isolation and additional laboratory or other diagnostic studies. This all adds to the imbalance between resource allocation for primary and secondary healthcare by diverting scarce funds to the management of potentially preventable conditions. Figures in 2011 from the NHS Information Centre show that the number of patients picking up life threatening infections has doubled over 2 years. Poor hygiene on wards is thought to be responsible for this increase.
Infection experts warn that some of the most serious nosocomial infections are becoming ‘hyper resistant’ to antibiotics. A large majority of hospital patients are treated with antimicrobial drugs and this promotes the emergence of multi drug resistant strains of bacteria. Antibiotics are becoming less effective because of this resistance. As they are more commonly used, bacteria resistant to the treatments emerge. Many strains of pneumococcal, staphylococci and tuberculosis are currently resistant to almost all antibiotics which were once effective.
Multi resistant Klebsiella, which causes pneumonia and meningitis and pseudomonas aeruginosa, which can cause severe tissue damage or septic shock, are now extremely prevalent in many hospitals. Some people are more susceptible to hospital acquired infections due to various reasons. The elderly are frailer already because of their age and impaired immune functions due to anatomic changes as they get older. Old age is associated with a decreased immune system, this is known as immunosenescence.
Michelle Mitchell, charity director of Age UK, reports that people over the age of 60 are 88% more likely to pick up a hospital acquired infection. People receiving chemotherapy are at an increased risk when their white blood cell count is low. White blood cells are the body’s main defence against infection so when they are at a low level, patients are immunocompromised and more susceptible to acquire an infection. Those with underlying health problems are more likely to suffer severe consequences from nosocomial infections and may find it much more difficult to recover.
Many factors promote hospital acquired infections including decreased immunity amongst the patients, an increasing variety of medical procedures and invasive techniques which create potential routes for the infections and the transmission of drug-resistant bacteria. With the ever growing populations of UK hospitals meaning crowded wards, poor infection control practices may facilitate the transmission of bacteria. The environmental factor is an important one as both infected patients and those with an increased risk of infection congregate in hospital wards.
As patients are transferred from one unit to another and patients who are highly susceptible are in one area e. g. intensive care, burns units etc, the risks of transferring the infection are increased. There are several modes of transmission for nosocomial infections and the most frequent are; exogenous – cross-infection from one person to another either patients or staff, endogenous – from patients own skin, airborne – coughing, sneezing, respiratory equipment or air-conditioning and contact transmission – contaminated hands or equipment, contaminated ‘sharps’ injury.
The most frequent nosocomial infections are of surgical wounds, urinary tract and lower respiratory tract. Urinary infections are the most common, the World Health Organisation survey shows that as many as 80% of infections are linked to the use of bladder catheters. Intravenous catheters are thought to be responsible for many nosocomial infections. The insertion of a needle or canula causes a break in the body’s natural defences and leaves the patient vulnerable to infection if not done properly or without the use of disinfection.
Surgical site infections are not as common but are also frequent. These infections are usually acquired during the operation itself, either from the medical equipment, the air or the staff (exogenously) or from the flora on the patient’s own skin (endogenously). There are also other potential sites of infections in patients such as skin and tissue infections from burns, ulcers or open wounds which encourage bacterial colonisation; infections of the reproductive organs such as endometriosis following childbirth and also gastroenteritis.
This is the most common nosocomial infection in children where rotavirus is the main pathogen. In adults, the major cause of nosocomial gastroenteritis is clostridium difficile. Bacteria are the most common nosocomial infections in hospitalised patients. For example, clostridium, which are anaerobic Gram-positive rods causing gangrene. Clostridium difficile infection is a bacterial infection which affects the digestive system. This nosocomial infection affects patients differently with symptoms ranging from mild to severe.
Sufferers experience diarrhoea, high temperatures above 38c and painful stomach cramps. The most serious condition it can cause is toxic mega colon, a severe swelling of the bowel caused by a build up of gas and it is life threatening. Gram-positive bacteria cause a wide variety of lung, bone, blood and heart infections, such as Staphylococcus aureus, and are often resistant to antibiotics. MRSA, methicillin resistant staphylococcus aureus, is known as a hospital ‘superbug’ and is resistant to a number of widely used antibiotics which makes it harder to treat than other bacterial infections.
Enterobacteriacae, Escherichia coli, Proteus and Klebsiella bacteria can all cause serious infections in the areas where catheters or canulas are inserted and are also highly resistant. Many other bacteria also pose a risk in hospitals, for example Legionella which causes pneumonia. Viruses, such as hepatitis B and C are transmitted through transfusions, dialysis or injections and Rotavirus through hand to mouth contact; all increase the possibility of nosocomial infections. Parasites and fungi are easily transmitted amongst hospitalised patients.
When a patients normal defence mechanisms are low or they have lower resistance than normal due to illnesses such as HIV or cancer, these parasites and fungi can cause infections. Examples include Candida albicans, Cryptosporidium and Aspergillus. Sarcoptes scabies is a parasite which has caused numerous outbreaks of nosocomial infections. The responsibility for preventing nosocomial infections lies with all the individuals and services which provide healthcare. A high occurrence of infection could be evidence of a poor quality of delivery in the health service.
Every hospital in the UK must have policies in place to ensure the control and prevention of infection. Every health care setting, especially hospitals, must have comprehensive policies in place to control and prevent nosocomial infections, as well as programmes of training for staff. These policies should include information about the removal of sources of infections by treatment and decontamination processes and information about preventing transfer by hand hygiene techniques, aseptic procedures and, where appropriate, isolation.
Good hand hygiene is an important part of controlling and preventing infections as hands can very easily transfer micro-organisms. Regular and thorough hand washing remains the most crucial intervention in infection control in both nosocomial and non nosocomial cases. Gloves can aid in the reduction of nosocomial infections but should be used to supplement hand washing, not replace it. It is obvious that excellent infection control is essential but due to the complex nature of infections, it isn’t always easy to achieve it.
There are several barriers which can hinder effective practice such as poor knowledge, inadequate facilities or time pressures on staff. These infections are worth controlling in terms of benefits in mortality rates, duration of patients stays in hospital and cost to the NHS and economy as a whole. What is needed is constant monitoring and attention by healthcare workers to what are basic measures.
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