Nosocomial infection

Note: Don't read this and panic about your gallbladder surgery next week.

What happens most of the time is that a humidifier or thermometer becomes contaminated and passed on to another patient. The odds of this happening are slim, thanks to new regulations and safety precautions. You're not going to get plague from the guy in the next room, there are air HEPA filters to stop that. This phrase is used more for doctors and nurses who touch an infected needle or catch a cold from a patient. While a patient treated for a broken rib may get pneumonia, the odds are very very low.

The main subject of Robin Cook's book Contagion

Also known as Hospital-acquired Infection.

Cross-infection occuring between patients or hospital personnel to patient, presents a constant hazard and occurs in about 5% of hospital admissions (about 2 million people per year in the US) causing an estimated 20,000 deaths.

The cause is partly due to the prevalence of diseased patients, but is mainly due to the presence of pathogenic microorganisms which are selected by the hospital environment.

Hospitals are especially hazardous for several reasons:

1. Patients may have compromised immunity, weakening their ability to fight off infection
2. Hospitals must treat patients who are infected with virulent pathogens some of which may be highly contagious
3. Patients are often crowded together in rooms and wards
4. Hospital personnel (doctors, nurses etc.) move between patients increasing the probability of a transfer of pathogens
5. Hospital procedures (venepuncture, catheterization, biopsy etc.) carry a risk of introducing pathogens to a patient
6. Newborn babies are especially susceptible to certain infections because they lack a developed immune system
7. Surgery presents a major hazard, as not only are highly suscepible parts of the body open to contamination, but the stress of surgical procedures often diminish a patient's ability to fight off infection
8. Some drugs, especially those used to treat cancer or those used before and after organ transplants, suppress the immune system of the patient
9. Antibiotic use carries the risk of selecting for antibiotic-resistant pathogens

Major types of Nosocomial Infection

• Urinary tract 41%
• Surgical 18%
• Respiratory 16%
• Septicaemia 7%
• Skin infections 6%
• Other 12%

Bacterial pathogens most often associated with nosocomial infections

• Escherichia coli
• Pseudomonas aeruginosa
• Enterococcus faecalis
• Staphylococcus aureus
• Candida albicans

Two approaches to controlling nosocomial infection have been remarkably successful.

1. The Centers for Disease Control and Prevention's 1987 "Universal Blood and Body Fluid Precautions"
2. Hepatitis B vaccination

Under the universal precautions, all body fluids are treated as if they are potential sources of HIV, Hepatitis B, or other blood-bourne pathogens. The precautions recommend the use of gloves and other protective barriers as well as the careful handling and disposal of used needles and other sharps.

Statistics demonstrate the impact of these two infection control measures. A 1990 study by the CDC found that cases of Hepatitis B amongst healthcare workers between 1982 and 1988 dropped 75%.