MDR TB Commentary
by Alan Cantwell MD and Dr. Lawrence
Broxmeyer MD
6-3-7
In view of the continuing media stories regarding the killer TB and the 31-year
old Atlanta man accused of spreading it via airplane travel, Dr Broxmeyer and I
would like to add some comments/research to the controversy.
Thanks,
Alan Cantwell MD
Lawrence Broxmeyer MD is a New York internist who writes frequently on issues
pertaining to tuberculosis. His recent paper "Diabetes mellitus, TB, and the
mycobacteria", as well as other publications, are available on-line at the
medamerica.org website. Alan Cantwell MD is a retired dermatologist who has
written extensively on TB- related bacteria in cancer and AIDS. Some of his
publications can be found at the joimr.org website.
Drug-Resistant TB And The New
Global HysteriaSurrounding XDR TB
A review of the medical literature clearly shows that multi-drug resistant (MDR)
tuberculosis (TB) and extensively drug-resistant (XDR) TB has been increasing in
number for the past several decades. It is undoubtedly a more common problem
than previously recognized.
It is also well accepted than TB is more frequent in the immigrant population
than in the native born American population. For example, a TB study sponsored
by the CDC in Los Angeles County during 1992-1994 concluded that foreign-born
immigrants comprised 64% of all reported cases. Half were born in Mexico or in
Central America. Screening procedures at that time also identified a large
proportion of cases among recently arrived South-east Asians.
During the 1990s, multi-drug-resistant (MDR) tuberculosis, defined as resistance
to at least isoniazid and rifampin, emerged as a threat to TB control, both in
the United States and worldwide.
A CDC report in 2006 concluded that 4% of the multi-drug resistant (MDR) TB
isolates in the US were extensively drug resistant (XDR). In Latvia, Europe, XDR
isolates comprised 19% of the MDR isolates; and in South Korea XDR strains were
15% of the isolates.
The "extreme type" of XDR TB is certainly not rare. Many people carry TB
bacteria; and TB bacteria mutate - and with bacterial mutations comes inevitable
drug resistance.
Why is the CDC and the media making such a big deal about one case XDR TB
discovered in a healthy-looking young white male lawyer from Atlanta when MDR
and XTB cases are widespread worldwide?
Why pick on this poor guy when a spot of his lung was detected by X-rays 5
months earlier, and he was placed on anti-TB antibiotics for more than two weeks
before he took his now infamous plane trip to Europe.
Until this Atlanta lawyer was made the media Poster Boy for TB, few people
thought about or cared about an epidemic of TB. When the current media obsession
with "killer" TB subsides, one can only hope that some sanity is restored to the
realities of modern TB.
Lawrence Broxmeyer MD
www.medamericaresearch.org
Alan Cantwell MD
www.ariesrisingpress.com
References and Summaries:
N Engl J Med. 1996 Apr 11;334(15):933-8. Links
Comment in:
N Engl J Med. 1996 Apr 11;334(15):981-2.
N Engl J Med. 1996 Aug 29;335(9):675; author reply 675-6.
Transmission of multidrug-resistant Mycobacterium tuberculosis during a long
airplane flight.
Kenyon TA,
Valway SE,
Ihle WW,
Onorato IM,
Castro KG.
Epidemiology Program Office, National Center for HIV, STD, and TB Prevention,
Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
BACKGROUND. In April 1994, a passenger with infectious multi-drug resistant
tuberculosis traveled on commercial-airline flights from Honolulu to Chicago and
from Chicago to Baltimore and returned one month later. We sought to determine
whether she had infected any of her contacts on this extensive trip. METHODS.
Passengers and crew were identified from airline records and were notified of
their exposure, asked to complete a questionnaire, and screened by tuberculin
skin tests. RESULTS. Of the 925 people on the airplanes, 802 (86.7 percent)
responded. All 11 contacts with positive tuberculin skin tests who were on the
April flights and 2 of 3 contacts with positive tests who were on the
Baltimore-to-Chicago flight in May had other risk factors for tuberculosis. More
contacts on the final, 8.75-hour flight from Chicago to Honolulu had positive
skin tests than those on the other three flights (6 percent, as compared with
2.3, 3.8, and 2.8 percent). Of 15 contacts with positive tests on the May flight
from Chicago to Honolulu, 6 (4 with skin-test conversion) had no other risk
factors; all 6 had sat in the same section of the plane as the index patient
(P=0.001). Passengers seated within two rows of the index patient were more
likely to have positive tuberculin skin tests than those in the rest of the
section (4 of 13, or 30.8 percent, vs. 2 of 55, or 3.6 percent; rate ratio, 8.5;
95 percent confidence interval, 1.7 to 41.3; P=0.01). CONCLUSIONS. The
transmission of Mycobacterium tuberculosis that we describe aboard a commercial
aircraft involved a highly infectious passenger, a long flight, and close
proximity of contacts to the index patient.
PMID: 8596593 [PubMed - indexed for MEDLINE]
Tuber Lung Dis. 1996 Dec;77(6):524-30. Links
Tuberculosis among foreign-born persons in Los Angeles County, 1992-1994.
Zuber PL,
Knowles LS,
Binkin NJ,
Tipple MA,
Davidson PT.
Division of Tuberculosis Elimination, Centers for Disease Control and
Prevention, Atlanta, GA 30333, USA.
OBJECTIVES: To describe the epidemiology of foreign-born tuberculosis (TB) cases
in Los Angeles County and to evaluate current TB screening and follow-up of
immigrants and refugees (I&R) to the USA. DESIGN: Retrospective analysis of the
Los Angeles County TB registry between October 1992 and December 1994. We
matched all cases who entered the USA during fiscal year 1993 (FY93) with a
database from the tracking system of I&R with suspected TB. RESULTS:
Foreign-born persons accounted for 64% of all reported TB cases. Half were born
in Mexico or Central America. Standardized incidence rates were 3-5 times higher
than those of US- born persons for Mexicans and Central Americans, 6-7 times
higher for North-east Asians, and 10-15 times higher for South-east Asians.
Among foreign-born cases who arrived during FY93, 5% of the Mexicans and Central
Americans, 48% of the North-east Asians and 67% of the South-east Asians were
registered by the tracking system. CONCLUSION: Mexicans and Central Americans
accounted for the majority of cases but had a lower incidence of TB than Asians.
The current screening procedures identify a large proportion of cases among
recently arrived South-east Asians, but contribute little to the control of TB
among Mexicans and Central Americans.
PMID: 9039445 [PubMed - indexed for MEDLINE]
MMWR Morb Mortal Wkly Rep. 2006 Mar 24;55(11):301-5.? Links
Emergence of Mycobacterium tuberculosis with extensive resistance to second-line
drugs--worldwide, 2000-2004.
Centers for Disease Control and Prevention (CDC).
During the 1990s, multidrug-resistant (MDR) tuberculosis (TB), defined as
resistance to at least isoniazid and rifampin, emerged as a threat to TB
control, both in the United States and worldwide. MDR TB treatment requires the
use of second-line drugs (SLDs) that are less effective, more toxic, and
costlier than first-line isoniazid- and rifampin-based regimens. In 2000, the
Stop TB Partnership's Green Light Committee was created to increase access to
SLDs worldwide while ensuring their proper use to prevent increased drug
resistance. While assisting MDR TB treatment programs worldwide, the committee
encountered reports of multiple cases of TB with resistance to virtually all
SLDs. To assess the frequency and distribution of extensively drug-resistant (XDR)
TB cases, CDC and the World Health Organization (WHO) surveyed an international
network of TB laboratories. This report summarizes the results of that survey,
which determined that, during 2000-2004, of 17,690 TB isolates, 20% were MDR and
2% were XDR. In addition, population-based data on drug susceptibility of TB
isolates were obtained from the United States (for 1993-2004), Latvia (for
2000-2002), and South Korea (for 2004), where 4%, 19%, and 15% of MDR TB cases,
respectively, were XDR. XDR TB has emerged worldwide as a threat to public
health and TB control, raising concerns of a future epidemic of virtually
untreatable TB. New anti- TB drug regimens, better diagnostic tests, and
international standards for SLD-susceptibility testing are needed for effective
detection and treatment of drug-resistant TB.
PMID: 16557213 [PubMed - indexed for MEDLINE]