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Published Date: 2007-01-24 00:00:00
Subject: PRO/EDR> Tuberculosis, extensively drug-resistant - Canada (ON)
Archive Number: 20070124.0318

TUBERCULOSIS, EXTENSIVELY DRUG-RESISTANT - CANADA (ONTARIO)
***********************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail, a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: Wed 24 Jan 2007
From: Mary Marshall <tropical.forestry@btinternet.com>
Source: Chronicle Herald (Nova Scotia) [edited]
<http://thechronicleherald.ca/Canada/554590.html>

A Toronto hospital is treating several cases of extensively drug
resistant tuberculosis, with one of the patients being held in
isolation under court order, the doctor overseeing the treatment said
Mon 22 Jan 2007.
Public health experts fear the dangerous strain of tuberculosis,
which is susceptible to very few of the anti-tuberculosis medications
normally used to treat TB, is a global health crisis in the making.
Dr. Monica Avendano, the physician in charge of the tuberculosis
service at West Park Healthcare Centre, said since 2004, her unit has
treated 5 or 6 patients with XDR TB, as it is called. All the
patients were either infected abroad or infected by a family member
who picked up the highly resistant strain elsewhere, she said.
"Currently, I am treating 3," said Avendano. "All of them have a
previous history of tuberculosis that was not well managed."
Multi-drug resistant TB and the more difficult extensively drug
resistant TB can arise one of 2 ways. A person with tuberculosis can
fail to take all their medication, as in the case of the "not-well
managed" patients to which Avendano referred. This spotty treatment
allows the bacterium to survive the assault of the drugs and develop
resistance to them. Or a person can be infected by contact with a
person sick with XDR TB. Two of the cases Avendano has treated fall
into this latter category.
"Both of the cases are young women who went to their country of
origin to look after their ailing grandmothers. And the ailing
grandmothers gave them TB. And it was XDR TB," she said.
She did not identify the countries involved. XDR TB has been found in
a number of places, including China, South Africa, and many republics
of the former Soviet Union. It is believed to have spread, still at
low levels, from these jurisdictions to developed countries.
The Public Health Agency of Canada currently doesn't know the scope
of the problem in this country. The last time Canadian TB statistics
were gathered, the provinces and territories were not asked to report
XDR TB cases. The TB statistics for 2006 -- which will be reported
sometime in 2007 -- will include XDR TB figures, agency spokesperson
Alain Desroches said in an e-mail.
Where such cases arise, they are treated in isolation, either with
the consent of the patient or with the help of the courts. "All
provinces and territories will use their public health legislation if
necessary to ensure treatment of XDR TB," said Dr. Edward Ellis,
manager of tuberculosis prevention and control with the public health
agency. "With TB, in my experience, there's never a problem getting a
court order if necessary. And nobody stands there saying: 'Oh, no,
let them go.'"
Avendano said treatment with alternative drug regimes is effective,
but it can take months of in-hospital care. Even then, it's not clear
whether these patients -- who will be required to be seen on an
ongoing basis -- are cured for life. That's because the strain hasn't
been around long enough, and the treatment regime being used is too
new to gauge its long-term efficacy.
[Byline: Helen Branswell]
--
ProMED-mail
<promed@promedmail.org>
[ProMED thanks Mary Marshall for this posting. A relevant discussion
on the XDR problem in tuberculosis can be found at: CDC: Emergence of
_Mycobacterium tuberculosis_ with Extensive Resistance to 2nd-Line
Drugs --- Worldwide, 2000-2004. 2006;55: 301-305. Parts of the report
are found below:
"17 690 isolates from the period 2000-2004 were tested for
susceptibility to at least 3 of the 6 2nd line drugs (SLD) classes.
Of these, 11 939 were from South Korea, of which 1298 (11 percent)
were multidrug-resistant (MDR, defined as resistance to at least
isoniazid and rifampin). From the other Global Supranational TB
Reference Laboratory (SRLs), 2222 (39 percent) of 5751 isolates were MDR.
Of the 3520 MDR isolates, 347 (10 percent) were XDR (defined as cases
in persons with TB whose isolates were resistant to isoniazid and
rifampin and at least 3 of the 6 main classes of SLDs
(aminoglycosides, polypeptides, fluoroquinolones, thioamides,
cycloserine, and para-aminosalicyclic acid), including 200 (15
percent) of 1298 from South Korea and 147 (7 percent) of 2222 from
other SRLs. The drug-susceptibility testing results were tabulated by
year and geographic region (on the basis of the country of origin of
the isolates) (Table 1; for table, see original URL. - Mod.LL).
XDR TB was identified in all regions but was most common in South
Korea (n = 200; 15 percent of all MDR TB isolates) and countries of
eastern Europe/western Asia (Armenia, Azerbaijan, Czech Republic,
Republic of Georgia, and Russia, n = 55; 14 percent of all MDR TB
isolates). The total number and proportion of XDR TB isolates
observed worldwide (excluding South Korea) increased from 14 (5
percent of MDR TB isolates) in 2000 to 34 (7 percent of MDR TB
isolates) in 2004. Year-specific proportions were stratified by
geographic region. Increasing proportions of XDR TB were found among
isolates from countries of eastern Europe/western Asia (n = 5 [9
percent] in 2000; n = 11 [17 percent] in 2003) and the group of
industrialized nations (Australia, Belgium, Canada, France, Germany,
Ireland, Japan, Portugal, Spain, UK, and USA, n = 3 [3 percent] in
2000; n = 25 [11 percent] in 2004).
USA national TB surveillance data included 169 654 patients with
drug-susceptibility testing results. During 1993-2004, a total of
2689 (1.6 percent) MDR TB cases were identified, of which 1814 (67
percent) had results reported for 3 or more SLD classes. Of these, 74
(4.1 percent) had resistance to 3 or more SLD classes and thus met
the criteria for XDR TB. Despite an overall decline in MDR TB
incidence in the USA, the proportion of XDR TB increased slightly,
from 37 (3.9 percent) of 944 cases during 1993-1996 to 20 (4.1
percent) of 489 during 1997-2000, to 17 (4.5 percent) of 381 in
2001-2004 (chi-square test for trend = 0.20; p = 0.66). During
1993-2002, patients with XDR TB were 64 percent more likely to die
during treatment (relative risk [RR] = 1.6; 95 percent confidence
interval [CI] = 1.2-2.2) than patients with MDR TB.
Among 605 MDR TB patients in Latvia who initiated therapy during
2000-2002, 115 (19 percent) had XDR TB. The proportion with XDR TB
increased from 30 (15 percent) of 204 in 2000, to 46 (21 percent) of
215 in 2001, to 39 (21 percent) of 186 in 2002 (chi-square test for
trend = 2.57; p = 0.11). Patients with XDR were 54 percent more
likely to die or have treatment failure (RR = 1.5; CI = 1.1-2.2)."
A map of Ontario, Canada showing the location of Toronto can be found at:
<http://us.i1.yimg.com/us.yimg.com/i/travel/dg/maps/a2/750x750_ontario_m.gif>.
- Mod.LL]

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