Nosocomial (Hospital-Acquired) Infections

 Affecting over 2 million patients in hospitals across the US every year

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Nosocomial (Hospital-Acquired) Infections Introduction  Background Causes Sources/Methods Of Transmission Person-to-Person Airborne Surgery Hospital Instruments What Is Being Done Now? Research Prevention Conclusion References

 

Introduction 

 

A nosocomial infection is one that is acquired during a patient's stay at a hospital or other healthcare facility.  This type of infection is also known as a Hospital-Acquired Infection. For an infection to be defined as such there should be no evidence of the infection being present at the time of admission.  Additionally, it must be manifested as a clinical disease, not a colonization which indicates the presence of microorganisms but without any adverse effects on the host.  Nosocomial infections are a major source of morbidity and mortality and in the United States, it is estimated that over 2 million patients develop these infections every year. (Ricks, 2007). Patients have an unusually high risk of developing infections for multiple reasons. These include their tendency to be immunocompromised due to any already present disease conditions or due to any type of invasive procedures, such as surgery or insertion of catheters and intubation tubes.  Patients are also at a high risk of developing resistance to antibiotic treatments due to the prevalence of drug-resistant pathogens in hospital environments.  Staphylococcus aureus and Enterococci are two of the leading causes of nosocomial infections and also have prevalent antibiotic resistant strains: Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Enterococci (VRE).  (Coia et al, 2006). These, in addition to other nosocomial infections such as hospital-acquired pneumonia and Escherichia coli infections, have led to an estimated $4.5 billion annual economic burden as a result of extended hospital stays, extra charges, and additional treatments. (Emori and Gaynes, 2002). Extra cost of NI varies between $1,000-4,500, with a mean $1,800 , but in pediatric patients especially in neonatal units extra costs over $10,000 are reported. (Nevzat, 2003).

 

Background

 

The term nosocomial infection derives from nosos, which is the Greek word for disease and komeo, which means to take care of. Nosocomial infections have existed as long as there have been hospitals. Hungarian physician Ignaz Semmelweis may have been the first to investigate the possibility when he noticed a connection between the high death rate of hospitalized patients and the exposure of patients to infectious microorganisms in 1847. Semmelweis noted the high rate of death from puerperal fever in women who gave birth at the Vienna General Hospital. Moreover, the high death rate was confined to a ward at which medical residents were present. Another ward, staffed only by midwives who did not interact with other areas of the hospital, had a much lower death rate. When the residents were made to wash their hands in a disinfectant solution prior to entering the ward, the death rate declined dramatically. At about the same time, the British surgeon Joseph Lister was investigating the importance of sterile conditions in hospitals. His use of phenolic solutions to clean surgical wounds helped lessen the spread of microorganisms to patients in hospitals. Lister also required surgeons to wear rubber gloves and freshly laundered operating gowns for surgery. His revelation that infections could be transferred from the surgeon to the patient was the beginning of hospital protocols to prevent infections, which has culminated in today's observance of sterile or near-sterile conditions in the operating theatre. (Wikipedia, 2008). 

Causes

Approximately one third of nosocomial infections are preventable. (Emori and Gaynes, 2002). The rate of nosocomial infections has increased for multiple reasons:

• Increasing antibiotic use leads to greater levels of antibiotic resistance in many bacteria. This makes the bacteria harder to treat and more durable, leading to greater spread.

• Sloppy hygiene by health care personnel, especially in the ICU where protocols might be sacrificed to increase the speed of responses to medical emergencies.

• Increase in the number of more vulnerable individuals, such as the elderly and immuno-compromised individuals (such as those living with HIV/AIDS). These patients are more susceptible to catching infections, and the increasing number of these patients has led to greater rates of infection.

• Older hospitals that need renovations. These cause greater levels of dust and debris in the hospital, possible leading to the spread of fungi and increased infections.

• Increase in the quality of hospitals leads to shorter stay times for less sick people. This means a greater number of more seriously ill patients, who are also more vulnerable to infections.

 

Recent studies have found that the rate of nosocomial infections in the U.S. has either remained steady or slightly increased over the last several years, while it has fallen in other countries. (Emori and Gaynes, 2002). This may be related to the differences in hospital information release policies in the U.S. Most states require their hospitals to collect data on nosocomial infections, yet allow them to keep that information private. In England, the British National Health Service requires hospitals to post that data where their patients can see it, as well as publishing them in the newspaper. This helps bring attention to the issue, and can force the hospitals to improve their conditions. Legislation has recently been developed in the U.S. in response to increased publicity for these infections, as well as due to the involvement of consumer advocacy organizations. (Edmond and Bearman, 2007). 

 

 

Person-to-Person

 

Contact transmission is the most common and most significant cause of nosocomial infections. There are two forms of contact transmission: direct-contact and indirect-contact. Direct-contact transmission is based on direct body surface contact between an infected or colonized person and an at-risk host. Direct-contact transmission thus involves the direct physical transfer of microorganisms from one person to another person. This can occur when any medical staff member performs an action that requires direct personal contact with the patient. Direct-contact transmission can also occur between two patients. Hospitals have strict rules to prevent the transmission of microorganisms. When medical personnel fail to follow these protocols when performing direct patient care, infection is morel likely to occur. A study conducted by Columbia University at New York Presbyterian Hospital found that patients who were handled by medical personnel with artificial fingernails had an increased rate of infection. As hospital size and number of personnel increase, so does the risk of infection. A study done by the CDC showed that patients in hospitals with 500+ beds were twice as likely to become infected as patients in smaller hospitals. (Emori and Gaynes, 2002).

 

 

Airborne

 

Although many nosocomial infections are associated with person-to-person contact, it has been estimated that airborne transmission of bacteria contributes to an estimated 10-20% hospital-acquired infections.  Airborne transmission refers to infections which are contracted from microorganisms which have become airborne, usually from coughing, sneezing or some other form of aerosolization. However, it can equally apply to dust particles and skin cells carrying pathogenic microorganisms. Fungal spores are also widely spread via the airborne route.  Droplet particles expelled through forms of aerosolization are small, settle slowly, and remain suspended in the air for a considerable period of time.  Given this long suspension time, particles can be carried long distances by currents and thus can be distributed widely throughout hospital buildings depending on ventilation conditions within healthcare facilities. (Emori and Gaynes, 2002).

 

 

Surgery

 

According to the Center for Disease Control’s (CDC) National Nosocomial Infections Surveillance (NNIS), surgical site infections (SSI’s) are the third most frequently reported nosocomial infection, accounting for 14%-16% of all nosocomial infections among hospitalized patients.  According to the NNIS, SSI’s are classified as being either incisional or organ/space, which involves any part of the anatomy other than incised body wall layers, that was opened or manipulated during an operation.  The most frequently isolated pathogens are Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus spp., and Escherichia coli.  An increasing proportion of SSI’s are caused by antibicrobial-resistant pathogens such as methicillin-resistant S. aureus (MRSA), which may reflect increasing numbers of severely ill and immunocompromised surgical patients and the impact of widespread use of broad-spectrum antimicrobial agents.  (Coia et al, 2006). Additionally, outbreaks or clusters of SSI’s have been caused by unusual pathogens that have been traced to contaminated adhesive dressings, elastic bandages, colonized surgical personnel, tap water, or contaminated disinfectant solutions.  The following are patient and operation characteristics that may influence the risk of SSI development: patient, age, nutritional status, diabetes, smoking, obesity, coexistent infections at a remote body site, colonization with microorganisms, altered immune response, length of preoperative stay, operation, duration of surgical scrub, skin antisepsis, preoperative shaving, preoperative skin prep, duration of operation, antimicrobial prophylaxis (very brief course of an antimicrobial agent initiated just before an operation begins), operative room ventilation, inadequate sterilization of instruments, foreign material in the surgical site, surgical drains, surgical technique, poor hemostasis (stoppage of bleeding), and tissue trauma. (Mangram et al, 1999).

 

 

Hospital Instruments

 

 

 

What Is Being Done Now?

 

Research

 

An important part of fighting hospital acquired infections is continuing research in the field, as well as increasing awareness about that research. Since 1980, the Journal of Hospital Infection has published studies and articles concerning nosocomial infections, and is one of the premier sources of information on the topic. Because of the vast and complex nature of hospital healthcare, there are a great number of worth-while research opportunities. Recent studies conducted include research on the contribution of hospitals beds to infection (Creamer and Humphreys, 2008), using bioinformatics to identify and learn more about infection causing pathogens (Cliff et al, 2008), and collecting statistics over time to determine important trends. (Thompson, 2008). These studies all focus on one individual part of the complex system of nosocomial infections. It's imperative to learn more about these infections, and to share that information with others. Being knowledgeable about these infections and aware of their causes and consequences are crucial to avoiding them. Conducting and presenting research is an essential part of decreasing the risk of nosocomial infections.

 

 

Prevention

 

In order to prevent further spread of these infections, hospitals have created strict policies. Special steps have been brought into common usage specifically to combat nosocomial infections. (Coia et al, 2006). These steps include:

1. Special wards for patients with highly contagious diseases, including isolated ventilation systems.
2. Increasing the number of hand washing stations around the hospital to encourage frequent hand washing especially between patients.  
3. Increasing the distance between patients
4. Avoiding the extensive use of antibiotics, as this can cause immunosuppression and increase the chances of getting an nosocomial infection. (Ferraresso, 2005).
5. Designing hospitals so that all areas are easy to clean and disinfect
6. Discontinuing possible use of single-use disposable items. 
7. Practice proper disinfection and sterile procedure in the operating room and with all medical instruments
8. Continued investigation into non-invasive surgeries and procedures
9. General awareness that prevention of nosocomial infection requires constant personal surveillance
10. Active oversight within the hospital

 

 

Conclusion

 

By further research, education, and awareness, the risk of nosocomial infections can be greatly reduced. It is important for all patients and health care workers to be informed and attentive, as it is part of their responsibility to help prevent these infections. Infection control programs are the center of all activities in decreasing the prevalence of nosocomial infections. An effective infection control program can greatly benefit both patients and health care workers, and release considerable health care resources for alternative use, thus saving both money and lives.

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References

 

 

Cliff PR, Sandoe JAT, Heritage J, and Barton RC. Use of multilocus sequence typing for the investigation of colonization by Candida albicans in intensive care unit patients. Journal of Hospital Infection. 2008. 69(1): 24-32.

 

Coia JE, Duckworth GJ, Edwards DI, Farrington M, Fry C, Humphreys H, Mallaghan C, and Tucker DR. Guidelines for the control and prevention of meticillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities. Journal of Hospital Infection. 2006. 63S: S1-S44.

 

Creamer E and Humphreys H. The contribution of beds to healthcare-associated infection: the importance of adequate decontamination. Journal of Hospital Infection. 2008. 69(1): 8-23.

 

Edmond MB and Bearman GML. Mandatory public reporting in the USA: an example to follow?” Journal of Hospital Infection. 2007. 65(2): 182-188.  

Emori TG and Gaynes RP. An overview of nosocomial infections, including the role of the microbiology laboratory.Clinical Microbiology Reviews. 1993. 6(4): 428-442. Guidelines for the Prevention of Intravascular Catheter-Related Infections. Center for Disease Control Morbidity and Mortality Weekly Report. 2002. 51(RR-10).

 

Ferraresso M, and Berardinelli L. Nosocomial infection in kidney transplant recipients: A retrospective analysis of a single-center experience. Transplantation Proceedings. 2005. 37 (6): 2495-2496.

 

Mangram AJ, Horan TC, Pearson ML, Silver LC and Jarvis WR. Guideline for Prevention of Surgical Site Infection. American Journal of Infection Control. 1999. 27(2): 97-134.

 

Nevzat YA. Socioeconomic burden of nosocomial infections. Indian Journal of Medical Sciences. 2003. 57(10): 450-456

 

Ricks D. Germ Warfare. Ms. Magazine. Spring 2007. 43-45.

 

Thompson DS. Estimates of the rate of acquisition of bacteraemia and associated excess mortality in a general intensive care unit: a 10 year study. Journal of Hospital Infection. 2008. 69(1): 56-61.

Wikipedia contributors. Nosocomial infection. Wikipedia, The Free Encyclopedia. 2008. Available at: http://en.wikipedia.org/w/index.php?title=Nosocomial_infection&oldid=210363611. Accessed May 5, 2008. 

Wilson SJ, Everts RJ, Kirkland KB, and Sexton DJ. A pseudo-outbreak of aureobasidium lower respiratory tract infections caused by reuse of "single use" stopcocks during bronchoscopy. Presented at the 37th Annual Meeting of the Infectious Diseases Society of America; Philadelphia, Pa; November 18-21, 1999. Session 34, Abstract 20.