CLINICAL LAB SCIENEC

CHAPTER 6: INTRODUCTION TO INFECTION CONTROL 119
might have eclipsed anything experienced previously, including that of bubonic
plague in the 15th century.
Most larger hospitals have comprehensive microbiology departments that are
able to identify and provide information for the initiation of adequate treatments
for a number of virulent pathogens. The five basic categories of microorganisms
are bacterial, viral, parasitic, rickettsial (a specialized bacterium of increasing
prevalence) , and fungal organisms. There are a few others, including subviral
particles called prions, (the source of the well-publicized “mad cow disease”). In
the case of rickettsial infections, the causative organism is usually transmitted by
a tick vector or carrier. Newer and less well-defined organisms other than these
five categories will doubtless be discovered.
The administration of antibiotics that are specific for only certain bacteria
is of little value in treating many bacterial organisms. Some broad-spectrum
antibiotics will indiscriminately destroy most bacterial strains, including normal
flora. This presents an opportunity for potentially harmful organisms to
take the place of the normal flora. Also, most respiratory infections such as the
common cold are caused by viruses against which antibiotics will do nothing
or may even exacerbate the growth of the virus. The wholesale prescribing of
antibiotics without identifying the presence of a pathogen has led to the rise
of many bacteria that are resistant to almost every antibiotic currently in use.
Many infections that are difficult to treat arise in patients who are hospitalized
and have contract ed an antibiotic-resistant organisms while in the facility.
Major sources of hospital-acquired infections (termed nosocomial infections
and iatrogenic infections) are caused by organisms that gain entry into and
colonize the body through the introduction of medical devices used for various
treatments.
With the proliferation of new medical procedures, some of an elective nature,
the rise in infections by resistant strains may cause a local epidemic within a
health care facility. In a number of cases, the Infection Control Committee will
trace certain strains of bacteria to a single physician, to instruments, or to other
health care workers. Protecting oneself against these dangerous organisms is
paramount, and most disease prevention efforts are focused toward teaching
the health care worker protection against a whole host of organisms. Infection
by bloodborne and airborne pathogens other than HIV, HBV , and TB, as well
as by environmental organisms, must be prevented through the use of precautions
designed to protect both the worker and the patient. Economy and efficiency
dictate that effective and conscientious efforts be pursued to avoid either
the health care professional, the student, or a patient from being infected. These
efforts will pay dividends in lowering our health care costs as a nation, as well
as preventing needless suffering and inconvenience.
To protect workers and employees against infection by HIV, HBV, or TB, the
infection control program of each medical facility and each educational institution
classifies job positions by potential for exposure. These levels of potential
risk range from Category I through Category III, with Category I including
workers at most risk, and Category III representing health care workers with
little risk of exposure. Although literally thousands of organisms are capable
of causing serious infections in humans, only two major organisms associated
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