Affiliations: Denver, CO
Dr. Sbarbaro is Professor of Medicine and Preventive Medicine, University of Colorado Health Sciences Center, Denver, CO.
Correspondence to: John A. Sbarbaro, MD, MPH, FCCP, Professor of Medicine and Preventive Medicine, 4200 E Ninth Ave, Denver, CO 80262
In 1992, Michael Iseman observed that: “As the epidemic
tide of tuberculosis recedes from the shores of America, small
tidepools of disease remain behind; pools populated by immigrants, the
elderly, and the immunocompromised.”1 The report by
Narita and colleagues in this issue of CHEST (see page 343)
gives us some insight into the impact of these tidepools on our
During the 43 months of their study (January 1, 1994, through July 31,
1997), 5,516 cases of active tuberculosis were identified in Florida,
keeping it among the top six states in the United States reporting the
highest annual rates of newly diagnosed tuberculosis
cases.2 By law, Florida requires all laboratories to
report positive cultures, thereby giving credence to the completeness
of these data.
While this number of new tuberculosis cases initially appears large, in
reality, when annualized against Florida’s total population of 14 to
14.5 million, the actual percentage of tuberculosis cases in the
population is stunningly low, ranging between 0.013% and 0.01%, a
percentage that should hardly generate attention much less any
significant concern.2 Simply stated, approximately one
case of new active tuberculosis per 10,000 Floridians was detected
during each year. Then why did CHEST determine that it was
important to publish this report that focuses on an even smaller number
of the cases, only 81 of the 5,516?
The answer is found in the “Results” section of the report by
Narita et al. All 81 patients received diagnoses of multidrug-resistant
(MDR) tuberculosis, which is defined as being resistant to both
isoniazid and rifampin. Forty-three of these patients (53%) had
accumulated their resistant organisms over a prolonged period of
treatment. We tactfully define this as “acquired” resistance
(ie, acquired through a combination of inadequate
professional care and unpredictable patient behavior; the result, of
course, being the selection and survival of resistant organisms that
were allowed to progressively mutate and flourish over time).
Of more concern is the fact that 38 patients from this group (47%;
nearly one half) had no history of prior treatment and developed their
disease as a result of exposure to an individual with MDR pulmonary
disease, again demonstrating that the old belief that drug-resistant
organisms are not as contagious as fully sensitive tubercle bacilli
was, and is, wrong.3
This becomes important in the light of our rediscovery of truths that
over recent years have been replaced by myths, which unfortunately have
acquired the legitimacy of facts through oft-repeated proclamations by
authoritative sources. For example, physicians often are told that
smear-negative tuberculosis patients are “not contagious,” a
rationale based on the reality that these individuals expel fewer
organisms than do smear-positive patients.
For those few persons unfamiliar with the definition of“
smear-positive,” that determination is made after carefully
examining 100 high-power microscopic fields over a 5- to 10-min period.
If a single tubercle bacillus is identified, the patient’s sputum
contains > 10,000 bacilli/mL and is smear-positive. While
smear-negative individuals do expel fewer bacilli, there has never been
a factual basis to believe that they are not contagious. Behr et
al4 have demonstrated quite convincingly that
smear-negative patients are one fifth (20%) as infectious as
Similarly, many physicians have come to believe that extensive exposure
is necessary to spread the disease. Again, this is not true.
Transmission is dependent not only on the time of exposure, but is
affected by sputum consistency, cough frequency, and, perhaps most
importantly, the environment shared by the patient and contacts. In
1995, the Centers for Disease Control and Prevention5
reported transmission to eight students in < 5 h of exposure.
When one considers that an adult tuberculosis patient has an average of
20 identifiable contacts plus those he or she exposes through casual
contact, even this very small number of MDR patients becomes of vital
importance to the community. It must be recalled that prior to the
advent of chemotherapy, two thirds of those patients with active
pulmonary tuberculosis were dead within a 5-year period. MDR
tuberculosis reopens the possibility of a fearful return to that era,
an apprehension that is validated by the authors’ findings that 32%
of the 81 MDR patients died during treatment.
It is for this reason that the treatment results of this
study are important. Despite a higher rate of social risk and HIV
infection, the mortality rate of 18% in the hospitalized
group was lower than the 26% mortality rate among patients treated on
an outpatient basis in the community. Similarly, only 48% of the
community group completed treatment despite the fact that outpatient
treatment was ensured through the use of directly observed therapy.
Seventy-nine percent of those admitted to the specialized inpatient
tuberculosis treatment facility at Holley Hospital completed therapy.
However, at what cost to society? Three to four days in a hospital can
cost as much as a year of outpatient care, even when that care is
directly administered. The average duration of inpatient care at Holley
Hospital was 270 days at a cost that easily surpassed $150,000 per
These are important findings for those involved in public policy
development. MDR tuberculosis represents a failure of physicians, of
public health officials, and of government. The message is clear: in
the face of an escalating rate of MDR tuberculosis throughout the world
and of the easy movement of diseased individuals between countries and
continents, it is essential that the United States, always a country of
immigrants, support and maintain its few remaining specialized centers
of tuberculosis treatment and research.
It is equally important that all physician organizations, especially
the American College of Chest Physicians, recognize that every
physician becomes a public health official when encountering a
tuberculosis patient and that every physician thereby assumes an
obligation to ensure that treatment is thorough and complete.
Unfortunately, a few academic centers continue to promulgate the belief
that since everyone with tuberculosis desires to regain their health,
everyone therefore will adhere to treatment if it is provided within a
well-functioning health system.6–7 Despite the presence of
multiple studies that repeatedly have proven this assumption to be
false and a world literature replete with reports of the success of
directly observed therapy, these centers contend that there is no firm
evidence demonstrating that directly observed therapy is both effective
and essential in the treatment of tuberculosis.
It is time for physician organizations from all parts of the
international community to reject such folly and firmly endorse
directly observed therapy as the professional standard of care. And as
a corollary standard, as soon as a patient is identified as not
adhering to treatment appointments and cannot be induced to cooperate
with directly observed therapy (even when provided with a range of
social supports), public health officials should immediately direct
that patient into a specialized tuberculosis treatment center. If we
fully and appropriately treat all patients during their first encounter
with tuberculosis, including the use of specialized facilities where
necessary, the risk and the fear of MDR tuberculosis can fade into
The alternative is to stand by and watch as the tidepools described by
Iseman slowly enlarge and perhaps return as a flood tide.
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