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Martien W Borgdorff

Publications and source records attributed to Martien W Borgdorff.

At least 19 recordsLinked to original sources
PubMed2006

Antituberculosis drug resistance in the south of Vietnam: prevalence and trends.

BACKGROUND: There is limited evidence that the DOTS (directly observed therapy, short course) strategy for tuberculosis (TB) control can contain the emergence and spread of drug resistance in the absence of second-line treatment. We compared drug-resistance levels between 1996 and 2001 in the south of Vietnam, an area with a well-functioning DOTS program. METHODS: Sputum specimens were collected from consecutively diagnosed patients with smear-positive TB at 40 randomly selected public TB clinics. Mycobacterium tuberculosis isolates were tested for susceptibility to first-line drugs. RESULTS: Among 888 new patients in 2001, resistance to any drug was observed in 238 (26.3%), resistance to isoniazid was observed in 154 (16.6%), resistance to rifampin was observed in 22 (2.0%), resistance to ethambutol was observed in 12 (1.1%), resistance to streptomycin was observed in 173 (19.4%), and resistance to both isoniazid and rifampicin (multidrug resistance [MDR]) was observed in 20 (1.8% [95% confidence interval, 1.0%-3.3%]). Among 136 previously treated patients in 2001, any resistance was observed in 89 (62.9%), and MDR was observed in 35 (23.2%). The prevalence of any drug resistance and of streptomycin resistance among new patients had decreased significantly (P<.01) since 1996; there was no increase in the prevalence of MDR. CONCLUSION: The prevalence of drug resistance decreased despite high initial levels of resistance to isoniazid and streptomycin and despite the absence of second-line treatment. Therefore, a DOTS program can contain drug-resistant TB in this setting.

Adolescent↗
PubMed2006

Tuberculin skin testing in patients with HIV infection: limited benefit of reduced cutoff values.

BACKGROUND: When determining eligibility for isoniazid preventive therapy of human immunodeficiency virus (HIV)-infected patients, the cutoff value of the tuberculin skin test (TST) is often reduced from an induration of 10 mm in diameter to one of 5 mm in diameter to compensate for loss of sensitivity. The effectiveness of this reduction depends on the underlying mechanism: a gradual decrease in skin test responsiveness with decreasing immunocompetence or an all-or-nothing switch to complete anergy. No published studies have assessed this directly in patients with tuberculosis. METHODS: We performed a cross-sectional study of TST responses and HIV infection among patients with sputum smear-positive pulmonary tuberculosis in 6 hospitals in Tanzania. Skin test anergy was defined as a TST reaction < or =2 mm in diameter. RESULTS: Of 991 patients with complete results, 451 (45.5%) had HIV infection. Anergy was observed in 111 (24.6%) of 451 HIV-infected patients and 18 (3.3%) of 540 HIV-uninfected patients (P<.001). The reaction size distributions among nonanergic HIV-infected and uninfected patients showed a limited difference (mean diameter +/- standard deviation, 15.9 +/- 5.0 mm and 16.8 +/- 3.8 mm, respectively; P=.048). The sensitivity of the TST among HIV-uninfected patients was 91.1% at a cutoff value of 10 mm and 95.2% at a cutoff value of 5 mm. The sensitivity of the TST among HIV-infected patients was 64.3% at a cutoff value of 10 mm and 71.2% at a cutoff value of 5 mm; the sensitivity of the TST was 67.6% and 74.5%, respectively, after adjustment for tuberculosis-specific anergy. CONCLUSION: In subjects with tuberculosis disease and HIV infection, loss of TST sensitivity is predominantly attributable to anergy (i.e., an all-or-nothing phenomenon). The decrease in the proportion of false-negative TST results obtained by reducing the cutoff value from 10 mm to 5 mm is limited.

Adolescent↗
PubMed2006

The impact of the HIV epidemic on tuberculosis transmission in Tanzania.

OBJECTIVE: To assess the impact of the HIV epidemic on tuberculosis transmission in Tanzania by estimating the trend in annual risk of tuberculosis infection (ARTI) over the period 1983-2003. DESIGN: Tuberculin survey among school children aged 6-14 years, randomly selected by cluster sampling. METHODS: Primary outcome was the ARTI among children without a BCG vaccination scar. To obtain time trends, data were reanalysed from three previous surveys carried out at intervals of 5 years since 1983, using identical methods and definitions. RESULTS: Of 96,226 children included in the analysis (74% of those enrolled), 10,239 (11%) had no BCG scar. The ARTI was 0.68% (95% confidence interval 0.55-0.81). Despite a doubling of notification rates of smear-positive tuberculosis since 1983, this represents an average annual decline since the first survey of 2.7% (P < 0.001). The declining trend in ARTI was observed in 17 of 20 regions, with no association between this trend and region-specific prevalence of HIV infection among patients with tuberculosis (P = 0.575). A similar decline in ARTI was observed among children with a BCG scar and for various ways of estimating the prevalence of tuberculosis infection from the distribution of skin test reactions. CONCLUSION: Despite substantial increases in tuberculosis incidence, the overall population-level effect of the HIV epidemic on tuberculosis transmission in Tanzania has been limited. This suggests that in the presence of a strong control programme, the HIV epidemic has limited impact on tuberculosis transmission.

AIDS-Related Opportunistic Infections↗
PubMed2006

Finding patients eligible for antiretroviral therapy using TB services as entry point for HIV treatment.

OBJECTIVE: To estimate the proportion of antiretroviral therapy (ART) eligible adults (15-49 years) with tuberculosis potentially identifiable through tuberculosis services using a CD4 count below 350 cells/mm3 as cut-off value for ART initiation. METHODS: Using TB notification rate data, HIV seroprevalence data, and estimates of the size of the adult population (15-49 years) in 18 sub-Saharan African countries with an HIV seroprevalence of > 5%, calculations of the number of ART eligible adults with tuberculosis presenting to tuberculosis services were made. Assumptions were made on the tuberculosis notification rates in the age-group 15-49 years, the HIV-infected population with a CD4 count below 350 cells/mm3 and the relative risk of developing tuberculosis, and average duration from HIV infection to death. The probability of having a CD4+ count below 350 cells/mm3 given a diagnosis of tuberculosis was estimated using Bayes' theorem, and estimates of the number of patients with a CD4 count below 350 cells/mm3 identifiable through tuberculosis were made. The number needed to screen to identify one ART eligible patient through tuberculosis services was estimated for each country. RESULTS: ART eligible adults with tuberculosis potentially identifiable through tuberculosis services in the 18 countries ranged from 2% to 18% of the total HIV-infected adult population with a CD4+ count below 350 cells/mm3 and would average 10% of all such HIV patients. The number needed to screen to identify ART eligible patients through tuberculosis services ranged from 1.4 to 4.2, against 8.6 to 65.4 if adults aged 15-49 are randomly screened for low CD4 counts. CONCLUSION: Tuberculosis services are an important entry point for identifying ART eligible patients. Given that dually infected patients identified through tuberculosis services contributed to 10% of the HIV-infected adult population with a CD4 cell count below 350 cells/mm3 in the 18 sub-Saharan African countries, major efforts are required beyond the tuberculosis services in detecting patients that should benefit from ART. However, the low number needed to screen gives opportunity to use tuberculosis services in AIDS control and ART scaling-up programmes.

Adolescent↗
PubMed2006

Prospects for advancing tuberculosis control efforts through novel therapies.

BACKGROUND: Development of new, effective, and affordable tuberculosis (TB) therapies has been identified as a critical priority for global TB control. As new candidates emerge from the global TB drug pipeline, the potential impacts of novel, shorter regimens on TB incidence and mortality have not yet been examined. METHODS AND FINDINGS: We used a mathematical model of TB to evaluate the expected benefits of shortening the duration of effective chemotherapy for active pulmonary TB. First, we considered general relationships between treatment duration and TB dynamics. Next, as a specific example, we calibrated the model to reflect the current situation in the South-East Asia region. We found that even with continued and rapid progress in scaling up the World Health Organization's DOTS strategy of directly observed, short-course chemotherapy, the benefits of reducing treatment duration would be substantial. Compared to a baseline of continuing DOTS coverage at current levels, and with currently available tools, a 2-mo regimen introduced by 2012 could prevent around 20% (range 13%-28%) of new cases and 25% (range 19%-29%) of TB deaths in South-East Asia between 2012 and 2030. If effective treatment with existing drugs expands rapidly, overall incremental benefits of shorter regimens would be lower, but would remain considerable (13% [range 8%-19%] and 19% [range 15%-23%] reductions in incidence and mortality, respectively, between 2012 and 2030). A ten-year delay in the introduction of new drugs would erase nearly three-fourths of the total expected benefits in this region through 2030. CONCLUSIONS: The introduction of new, shorter treatment regimens could dramatically accelerate the reductions in TB incidence and mortality that are expected under current regimens-with up to 2- or 3-fold increases in rates of decline if shorter regimens are accompanied by enhanced case detection. Continued progress in reducing the global TB burden will require a balanced approach to pursuing new technologies while promoting wider implementation of proven strategies.

Antitubercular Agents↗
PubMed2006

Extrapulmonary tuberculosis by nationality, The Netherlands, 1993-2001.

This study describes the epidemiology of extrapulmonary tuberculosis (TB) in the Netherlands from 1993 through 2001. We assessed whether the increasing numbers of inhabitants with a non-Western ethnic background had an effect on the number of extrapulmonary patients. We used data from the Netherlands Tuberculosis Register and included all cases of TB diagnosed in the Netherlands between January 1, 1993, and December 31, 2001. Information on age, sex, nationality, year of diagnosis, culture result, anatomic location of the site of disease, and HIV status was retrieved from the register. Of 13,258 patients with TB, 8216 (62%) had pulmonary TB, and 5042 (38%) had extrapulmonary TB. Non-Dutch nationals were more likely to have most types of extrapulmonary TB. The growth of the number of inhabitants with a non-Western ethnic background in the Netherlands explains the proportional growth of extrapulmonary TB. Physicians need to be aware of the changing clinical picture of TB.

AIDS-Related Opportunistic Infections↗
PubMed2005

Rate of reinfection tuberculosis after successful treatment is higher than rate of new tuberculosis.

RATIONALE: In a high-tuberculosis (TB) incidence area of Cape Town, South Africa, there is a very high rate of unexplained recurrent TB. The incidence of new bacteriologically confirmed disease in the area is 313 per 100,000 individuals. OBJECTIVE: To estimate the rate of recurrent TB attributable to reinfection after successful treatment. METHODS: All patients with reported TB in the area between 1993 and 1998 were followed up to 2001 for disease needing retreatment (recurrences). Patients who were multi-drug-resistant or who had treatment failure, were transferred, or died during treatment were excluded. Analysis was restricted to patients for whom DNA fingerprinting of their Mycobacterium tuberculosis isolates was obtained. Reinfection TB was defined as a recurrent TB episode in which the strains of the separate episodes differed by more than four bands. MEASUREMENTS AND MAIN RESULTS: 612 of 897 (68%) patients had a DNA fingerprint available at enrollment. Median duration of follow-up was 5.2 years. Recurrent TB occurred in 108 of 612 (18%) patients, of whom 61 of 447 (14%) experienced recurrence after successful treatment, and 47 of 165 (28%) experience recurrence after default. Of the 108 patients with recurrent TB, 68 (63%) had a DNA fingerprint in the second episode. Among these patients, 24 of 31 (77%) recurrences after successful treatment and 4 of 37 (11%) recurrences after default were attributable to reinfection. The reinfection disease rate after successful treatment was estimated at 2.2 per 100 person-years. CONCLUSIONS: The age-adjusted incidence rate of TB attributable to reinfection after successful treatment was four times that of new TB. People who had TB once are at a strongly increased risk of developing TB when reinfected.

Adolescent↗
PubMed2005

Tuberculosis elimination in the Netherlands.

This study assessed progress towards tuberculosis (TB) elimination in the Netherlands by using DNA fingerprinting. Mycobacterium tuberculosis strains were defined as new if the IS6110 restriction fragment length polymorphism pattern had not been observed in any other patient during the previous 2 years. Other cases were defined as clustered and attributed to recent transmission. In the period 1995-2002, the incidence of TB with new strains was stable among non-Dutch residents and declined among the Dutch. However, the decline among the Dutch was restricted to those >or=65 years of age. Moreover, the average number of secondary cases per new strain did not change significantly over time. We conclude that the decline of TB in the Netherlands over the past decade was mainly the result of a cohort effect: older birth cohorts with high infection prevalence were replaced by those with lower infection prevalence. Under current epidemiologic conditions and control efforts, TB may not be eliminated.

Adult↗
PubMed2004

Proportion of tuberculosis transmission that takes place in households in a high-incidence area.

The prevalence of infection among household contacts of people with tuberculosis is high. This information frequently guides active case finding. We analysed DNA fingerprints of Mycobacterium tuberculosis from 765 tuberculosis patients in Ravensmead and Uitsig, adjacent suburbs of Cape Town, South Africa. In 129 households in which DNA fingerprints were available for more than one patient, we identified 313 patients, of whom 145 (46%) had a fingerprint pattern matching that of another member of the household. The proportion of transmission in the community that took place in the household was 19%, and therefore, in this high-incidence area, tuberculosis transmission occurs mainly outside the household.

Adult↗
PubMed2004

Mycobacterium tuberculosis, Beijing genotype strains not associated with radiological presentation of pulmonary tuberculosis.

Mycobacterium tuberculosis strains of the Beijing genotype have been involved in various outbreaks of multidrug-resistant tuberculosis. Some studies suggest that the infection with the Beijing genotype is associated with a different host immune response. Since this might also lead to a different chest X-ray (CXR) presentation, we compared CXRs of patients with pulmonary tuberculosis, 33 of whom were infected with the Beijing genotype and 76 with other genotypes. No significant differences were detected. We conclude that the Beijing genotype is not associated with a different CXR presentation.

Adult↗
PubMed2004

Transmission of tuberculosis in a high incidence urban community in South Africa.

BACKGROUND: The objective of this study was to identify risk factors for ongoing community transmission of tuberculosis (TB) in two densely populated urban communities with a high incidence rate of TB in Cape Town, South Africa. METHODS: Between 1993 and 1998 DNA fingerprints of mycobacterial isolates from TB patients were determined by restriction fragment length polymorphism (RFLP). Cases whose isolates shared identical fingerprint patterns were considered to belong to the same cluster and to be attributable to ongoing community transmission. RESULTS: The average annual notification rate of new smear positive TB was 238/100000. In all, 1023/1526 reported patients were culture positive, and RFLP was available for 768 (75%) of the isolates from these patients. Since some patients experienced more than one infection during the study period, 797 cases were included in the analysis. Of the cases, 575/797 (72%) were clustered. Smear-positive cases and those who were retreated after default were more likely to be clustered than smear-negative and new cases, respectively. Patients from Uitsig were more often part of large clusters than were patients from Ravensmead. Age, sex, year of diagnosis, and outcome of disease were not risk factors for clustering, nor for being the first case in a cluster, although various analytical approaches were used. CONCLUSIONS: The incidence and proportion of cases that are clustered in this area are higher than reported elsewhere. An overwhelming majority of TB cases in this area is attributed to ongoing community transmission, and only very few to reactivation. This may explain the lack of demographic risk factors for clustering.

Adolescent↗
PubMed2004

Transposition rates of Mycobacterium tuberculosis IS6110 restriction fragment length polymorphism patterns.

To determine the rate at which IS6110 restriction fragment length polymorphism (RFLP) patterns in Mycobacterium tuberculosis change over time, we applied a smooth nonparametric survival model to several data sets, including data from previous publications on the rate of change. The results strongly suggest a simple parametric model, with an instantaneous change at time zero and essentially a zero rate of change thereafter. Our interpretation of the results is that at the time of collection of the first isolate, more than one strain is present. We speculate that the selection of mutant strains is most likely during rapid growth, revival of the dormant bacteria, and/or adaptation to a new host. The parameter most accurately describing changing RFLP patterns is the proportion of isolates with band changes, rather than the half-life or the rate of change.

DNA Transposable Elements↗
PubMed2004

High incidence of pulmonary tuberculosis persists a decade after immigration, The Netherlands.

Incidence rates of pulmonary tuberculosis among immigrants from high incidence countries remain high for at least a decade after immigration into the Netherlands. Possible explanations are reactivation of old infections and infection transmitted after immigration. Control policies should be determined on the basis of the as-yet unknown main causes of the persistent high incidence.

Adolescent↗
PubMed2004

New measurable indicator for tuberculosis case detection.

The World Health Organization's goal for tuberculosis (TB) control is to detect 70% of new, smear-positive TB cases and cure 85% of these cases. The case detection rate is the number of reported cases per 100,000 persons per year divided by the estimated incidence rate per 100,000 per year. TB incidence is uncertain and not measured but estimated; therefore, the case detection rate is uncertain. This article proposes a new indicator to assess case detection: the patient diagnostic rate. The patient diagnostic rate is the rate at which prevalent cases are detected by control programs and can be measured as the number of reported cases per 100,000 persons per year divided by the prevalence per 100,000. Prevalence can be measured directly through national prevalence surveys. Conducting prevalence surveys at 5- to 10-year intervals would allow countries with high rates of disease to determine their case detection performance by using the patient diagnostic rate and determine the effect of control measures.

Global Health↗