Biomedical subjects

M W Borgdorff

Publications and source records attributed to M W Borgdorff.

At least 19 recordsLinked to original sources

PubMed2006

Public health impact of isoniazid-resistant Mycobacterium tuberculosis strains with a mutation at amino-acid position 315 of katG: a decade of experience in The Netherlands.

A previous limited study demonstrated that Mycobacterium tuberculosis isolates with a mutation at amino-acid position 315 of katG (Delta315) exhibited high-level resistance to isoniazid and were more frequently resistant to streptomycin. In the present study, isoniazid-resistant M. tuberculosis isolates from 8,332 patients in The Netherlands (1993-2002) were screened for the Delta315 mutation. Isoniazid resistance was found in 592 (7%) isolates, of which 323 (55%) carried Delta315. IS6110 restriction fragment length polymorphism analysis showed that Delta315 isolates occurred in clusters, suggesting recent transmission, at the same frequency as isoniazid-susceptible isolates. In contrast, other isoniazid-resistant isolates clustered significantly less frequently. Delta315 isolates were high-level isoniazid-resistant, streptomycin-resistant and multidrug-resistant significantly more often, and may have a greater impact on public health, than other isoniazid-resistant isolates.

Adolescent↗

PubMed2006

Treatment outcomes by drug resistance and HIV status among tuberculosis patients in Ho Chi Minh City, Vietnam.

OBJECTIVE: To assess the combined effects of drug resistance, HIV infection and treatment regimen on treatment outcomes of smear-positive tuberculosis patients in Ho Chi Minh City, Vietnam. METHODS: A representative sample of patients diagnosed in 1998-2000 in 12 urban districts was offered HIV testing and submitted sputum for Mycobacterium tuberculosis culture and drug susceptibility testing. New patients were treated with 2SHRZ/6HE in nine districts and with 2SHRZ/4RH in three districts. RESULTS: The cure rate was 87% (1240/1430) among new patients compared to only 73% (287/391) among previously treated patients. Failure was associated with multidrug resistance (adjusted odds ratios [aOR] 49.6 and 16.6, respectively) and combined resistance to isoniazid (INH) and streptomycin (SM) (aOR 13.4 and 4.8), but not with HIV infection. New patients had an increased risk of failure on treatment with 2SHRZ/4RH compared to 2SHRZ/6HE if the isolate was resistant to INH and SM (aOR 2.8, P = 0.016). Death during treatment occurred in 15 of 50 HIV-infected patients (30%). Mortality was significantly associated with HIV infection (aOR 29.9), multidrug resistance (aOR 4.7) and other resistance to two or more drugs (aOR 2.1). CONCLUSION: In Vietnam, adaptation of treatment regimens should be considered, and interventions are needed to reduce the high mortality among HIV-infected patients.

AIDS-Related Opportunistic Infections↗

PubMed2006

Drug resistance among smear-positive tuberculosis patients in Ho Chi Minh City, Vietnam.

OBJECTIVES: To assess the pattern of drug resistance among smear-positive tuberculosis (TB) patients in an inner city area in Vietnam. METHODS: A random sample of patients diagnosed by the national TB programme (NTP) were offered HIV testing and submitted sputum for Mycobacterium tuberculosis drug sensitivity testing. RESULTS: Of 1433 isolates from new patients, 360 (25%) were resistant to isoniazid (INH), 57 (4.0%) to rifampicin (RMP), 421 (29%) to streptomycin (SM) and 28 (2.0%) to ethambutol. Among 401 previously treated patients, this was 218 (54%), 109 (27%), 217 (54%) and 26 (7%), respectively. Multidrug resistance (MDR) was observed in 55 (3.8%) new and 102 (25%) previously treated patients. RMP resistance was strongly associated with resistance to INH (OR 46) and INH plus SM (OR 91, P = 0.004). Prevalence of drug resistance tended to decrease with age. Neither any resistance nor MDR was significantly associated with HIV infection. CONCLUSIONS: In this inner city area, levels of drug resistance, in particular of MDR among previously treated patients, are high. This may be related to the use of NTP regimens in the context of highly prevalent combined SM and INH resistance which may favour acquisition of RMP resistance.

Adolescent↗

PubMed2006

Evaluation of sputum smear microscopy in the National Tuberculosis Control Programme in the north of Vietnam.

OBJECTIVE: To assess the yield of sputum smear microscopy and sex differences in the National Tuberculosis Control Programme in the north of Vietnam. METHODS: Review of registers of 30 randomly selected laboratories (26 district, 4 provincial level). RESULTS: The average daily workload per technician was 4.4 examinations in district and 5.3 examinations in provincial laboratories. To find one smear-positive case, 9.7 suspects were examined and 29.3 smears done. The smear-positive rate (mean 10.3%) was higher among men (11.6%) than among women (8.4%, P < 0.001). There were more men than women among tuberculosis (TB) suspects (male:female ratio 1.36, 95%CI 1.19-1.54), but even more so among smear-positive patients (1.89, 95%CI 1.64-2.14), irrespective of specimen quality and number of smears examined. Three smears were examined for 18,055 suspects (61.7%). The incremental gain was 33.5% and 4.9% for the second and third smear examination, respectively; 186 (95%CI 160-221) smears needed to be examined to find one additional case of TB with a third serial examination. CONCLUSION: The diagnostic process seemed generally efficient. The male:female ratios suggest higher TB incidence in men rather than lower access to TB facilities for women. The third smear examination could be omitted.

Adolescent↗

PubMed2006

An evaluation of symptom and chest radiographic screening in tuberculosis prevalence surveys.

SETTING: A tuberculosis (TB) prevalence survey was performed in 2002 in two urban communities in Cape Town, South Africa. The population was 36,334 in 2001, and the TB notification rate was 341 per 100,000 population for new smear-positive TB in 2002. OBJECTIVE: To evaluate the relative contributions of symptom and chest radiographic (CXR) screening in the detection of subjects with smear- and/or culture-positive TB in prevalence surveys. DESIGN: Information on symptoms, CXR abnormalities, sputum smear and culture was gathered from a random cluster sample of 1170 adults (aged > or = 15 years). Smear and/or culture-positive TB was used as the gold standard. RESULTS: Of 1170 adults, 29 had bacteriologically positive TB (smear- and/or culture-positive). The presence of any abnormalities on CXR had the highest sensitivity for detecting subjects with bacteriologically positive TB (0.97, 95%CI 0.90-1.00). Specificity for any abnormalities on CXR was 0.67 (95%CI 0.64-0.70). The specificity of any of five TB-related symptoms was 0.68 (95%CI 0.65-0.71). Individual symptoms had low sensitivities, ranging from 0.10 for fever to 0.54 for cough of > or = 2 weeks. CONCLUSION: In this TB prevalence survey, CXR screening, but not symptom screening, was a sensitive alternative to sputum examination of all participants.

Adolescent↗

PubMed2006

Tuberculosis epidemiology in six provinces of Vietnam after the introduction of the DOTS strategy.

SETTING: Six provinces in Vietnam where the DOTS strategy was introduced in 1989. OBJECTIVE: To assess the impact of improved tuberculosis (TB) control on TB epidemiology in Vietnam. METHODS: Data from the surveillance system in the period 1990-2003 were analysed to assess trends of notification rates and the mean ages of notified cases. Data from repeated tuberculin surveys in the period 1986-2002 were estimated to assess the prevalence of TB infection, the annual risk of infection and its trend using various cut-off points in those with and without bacille Calmette-Guérin (BCG) scar. RESULTS: Age-standardised notification rates in the period 1996-2003 declined significantly, by 2.6% to 5.9% per year, in five provinces. However, in four provinces notification rates in the age group 15-24 years increased significantly, by 4.5% to 13.6% per year, during this period. The mean age of newly diagnosed patients with smear-positive TB increased up to 1995 but decreased thereafter. The annual risk of TB infection showed a significant annual decrease (4.9% per year) in one province in surveys performed between 1986 and 1997, and in two provinces (6.6% and 4.7%) in surveys conducted between 1993 and 2002. CONCLUSION: These data suggest limited impact to date of the DOTS strategy in Vietnam.

Adolescent↗

PubMed2005

Association between smoking and tuberculosis infection: a population survey in a high tuberculosis incidence area.

BACKGROUND: Associations between smoking and tuberculosis disease including death from tuberculosis have been reported, but there are few reports on the influence of smoking on the risk of developing Mycobacterium tuberculosis infection. The aim of this study was to determine the association between smoking and M tuberculosis infection. METHODS: In a cross sectional population survey, data on smoking and tuberculin skin test (TST) results of 2401 adults aged > or =15 years were compared. RESULTS: A total of 1832 (76%) subjects had a positive TST (> or = 10 mm induration). Of 1309 current smokers or ex-smokers, 1070 (82%) had a positive TST. This was significantly higher than for never smokers (unadjusted OR 1.99, 95% confidence interval (CI) 1.62 to 2.45). A positive relationship with pack-years was observed, with those smoking more than 15 pack-years having the highest risk (adjusted OR 1.90, 95% CI 1.28 to 2.81). CONCLUSION: Smoking may increase the risk of M tuberculosis infection.

Adolescent↗

PubMed2005

Tuberculosis infection in children who are contacts of immigrant tuberculosis patients.

The present study aimed to determine what proportion of children who are in close contact with immigrant tuberculosis (TB) patients are infected with Mycobacterium tuberculosis. For 1.5 yrs, 14 municipal health services in The Netherlands collected data from all non-Dutch TB patients and their contacts. Close contacts aged < 16 yrs received a tuberculin skin test (TST). A positive TST was defined as an induration of > or = 10 mm among nonvaccinated children, and > or = 16 mm among bacille Calmette-Guérin-vaccinated children. In total, 244 patients had 359 close contacts aged < 16 yrs. Nine out of the 359 (2.5%) had TB. A TST test was given to 298 out of the 359 (83%). Of the 115 contacts of 44 extrapulmonary TB patients, three (3%) had a positive TST. Of the 186 contacts of 58 positive pulmonary TB patients, 30 (16%) had a positive TST. Contacts of sputum smear-positive patients significantly more often had a positive TST (25%), compared with the contacts of sputum smear-negative patients (7%). Children born abroad significantly more often had a positive TST (20%) than children born in The Netherlands (5%). In conclusion, the prevalence of active tuberculosis and latent tuberculosis infection among children who are close contacts of immigrant tuberculosis patients is high and warrants an expansion of contact investigation.

Adolescent↗

PubMed2005

Establishment and development of the National Tuberculosis Control Programme in Vietnam.

OBJECTIVE: To describe the establishment and development of the National Tuberculosis Control Programme (NTP) of Vietnam. METHODS: Data were obtained from the surveillance system established by the new NTP in 1986 and based on the principles now described as the WHO DOTS strategy. RESULTS: The proportion of districts covered by the NTP increased from 40% in 1986 to almost 100% in 2000. The proportion of communes applying NTP guidelines increased from 18% in 1986 to 99.8% in 2000. The total number of tuberculosis cases notified increased from 8737 in 1986 to 89 792 in 2000. Most of these are new smear-positive cases. Based on WHO estimations of the incidence rate, the proportion of new smear-positive cases detected and put on short-course treatment has been over 70% since 1996. Reported cure rates with short-course chemotherapy are consistently over 85%. CONCLUSIONS: DOTS is feasible in a low-income, high-burden country. The main reasons for success were political commitment, a well-functioning health network, integration of tuberculosis control into the general health service at district level, a continuous supply of drugs and effective external support. Major challenges are long-term financial support, expansion to remote areas and vulnerable groups, definition of the role of the private sector, and future developments of the HIV epidemic and multidrug resistance.

Humans↗

PubMed2005

Tuberculin skin test: estimation of positive and negative predictive values from routine data.

OBJECTIVE: To estimate, using routinely available data, the predictive values of tuberculin testing with 2TU RT23 for detection of latent tuberculosis infection (LTBI) in the Dutch population as a basis for recommendations on cut-off values at various levels of infection prevalence. DESIGN: Smoothed distributions of TST reactions among 312 tuberculosis patients and 2848 healthy non-BCG-vaccinated persons were used to estimate the sensitivity and specificity at various cut-off values. RESULTS: Sensitivity was 98.9% at 5 mm, 95.4% at 10 mm and 79.8% at 15 mm cut-off. Specificity with the corresponding cut-offs was 95.3%, 96.3% and 97.1% before and 98.0%, 98.8% and 99.6% after adjustment for presumed LTBI. At 10 mm, the positive predictive value (PPV) was > 75% if the infection prevalence in the tested population was at least 10%, but strongly declined with lower prevalences. For lower prevalences a cut-off of 15 mm was proposed, as this results in a higher PPV without greatly affecting the negative predictive value. CONCLUSION: Estimation of the predictive values of the TST from routine data can be useful for establishing cut-off values for detection of LTBI in different populations with different tuberculin preparations.

Adult↗

PubMed2005

Development and evaluation of a new chest radiograph reading and recording system for epidemiological surveys of tuberculosis and lung disease.

OBJECTIVE: The development and evaluation of a new chest radiograph reading and recording system (CRRS) for community surveys of tuberculosis (TB) and lung disease. DESIGN: An experienced pulmonologist read 2608 chest X-rays (CXRs) performed as part of a TB prevalence survey using the newly developed CRRS. The kappa (kappa) for inter-reader agreement was calculated after a second reader reported on a stratified random sample of 810 (31%) of the 2608 CXRs. The kappa for intra-reader agreement was calculated from the repeated reporting of a stratified random sample of 104 CXRs. RESULTS: The kappa agreement between the two readers was 0.69 (95%CI 0.64-0.74) for abnormalities consistent with TB and 0.47 (95%CI 0.42-0.53) for any abnormalities. The kappa for intra-reader agreement was 0.90 (95%CI 0.81-0.99) for abnormalities consistent with TB and 0.85 (95%CI 0.74-0.95) for any abnormalities. CONCLUSION: This standardised method for CXR reading and recording provides satisfactory inter- and intra-reader agreement, making it suitable for surveys of TB and other forms of lung disease in the community. Its use will permit comparisons of results obtained in different surveys.

Epidemiologic Methods↗

PubMed2004

Increase of bone and joint tuberculosis in The Netherlands.

There has been an increase in the incidence of bone and joint tuberculosis (BJTB) in The Netherlands and we have carried out an epidemiological study in order to find an explanation for this increase. Data from 1993 to 2000 from The Netherlands Tuberculosis Register (NTR) were used. In 1993 there was a total of 52 patients with BJTB. This figure increased gradually to 80 in 1999 before decreasing to 61 in 2000. There was a total of 12447 patients with tuberculosis; BJTB was found in 532, accounting for 4.3% of all cases and 10.6% of all extrapulmonary cases. Localisation in the spine occurred in 56%. Certain immigrants, in particular from Somalia, were more likely to have BJTB than other immigrants or the native Dutch population. Increased age and female gender were associated with BJTB. Only 15% of BJTB patients also suffered from pulmonary tuberculosis. The usual long delay in the diagnosis of BJTB may be shortened if physicians are more aware of tuberculosis.

Adult↗

PubMed2004

Modeling and correction of digit preference in tuberculin surveys.

SETTING: Human observers generally have a strong tendency to round analog measurements or estimates to 'nice' ending digits, such as 0, 5, or even numbers. This is known as digit preference; it is a well-known phenomenon in frequency distributions of indurations collected in tuberculin surveys. Digit preference can distort estimates of prevalence and other statistical parameters. METHODS: We have developed a statistical model that combines smoothing by penalized likelihood and the transfer of counts from non-preferred to preferred digits, to obtain estimates of: 1) the smooth underlying distribution and 2) the amount of digit preference. RESULTS: To illustrate the validity of the model, it was applied to data from several countries. CONCLUSION: With the proposed model, digit preference can be quantified and frequency distributions of indurations can be corrected for it.

Algorithms↗

PubMed2004

Risk of infection with Mycobacterium tuberculosis in Malawi: national tuberculin survey 1994.

OBJECTIVE: To estimate the annual risk of tuberculosis infection among schoolchildren in Malawi. METHODS: A school survey was conducted in twelve randomly selected districts in Malawi. Children in standard 1-4 and aged 6-11 years were eligible. Tuberculin skin testing was performed according to World Health Organization/International Union Against Tuberculosis and Lung Disease guidelines. RESULTS: Of the 17123 eligible children, 80% were tested. Of those tested 79% were read. The prevalence of infection according to various criteria was 9-12% in children without bacille Calmette-Guerin (BCG) scar. The prevalence of reactions of 10 mm or more was lower in girls than in boys, increased with age, and was higher in those with than in those without BCG scar. The annual risk of infection was estimated to be within the range 0.6-1.4%. CONCLUSION: Annual risk of infection in Malawi was in the order of 1%. This study is expected to provide valuable baseline information for an assessment of the impact of human immunodeficiency virus (HIV) on tuberculosis transmission in Malawi.

Age Distribution↗

PubMed2003

[Research into new methods for diagnosing, treating and preventing tuberculosis].

Tuberculosis control requires improved diagnostics, drugs, and vaccines. Their development is facilitated by progress in immunology, molecular biology, and genomics. In addition to sputum smear and culture, amplification techniques can already be used to diagnose tuberculosis and antigen-detection tests for this purpose are being developed. Molecular typing and DNA microarrays provide new insights in the natural history and transmission of tuberculosis. In addition to established drugs such as rifampicin, isoniazid, pyrazinamide, and ethambutol, a limited number of new drugs have been discovered such as rifampicin derivates and fluorochinolones. Improved screening techniques and insights from genomics may lead to new drugs being discovered. Factors hampering the development and evaluation of new vaccines include problems with extrapolation from animal models, incomplete natural immunity, and limited knowledge about protective immunity. However, new candidate vaccines are being developed and will be tested on humans in the near future.

Animals↗

PubMed2003

The epidemiology of tuberculosis among asylum seekers in The Netherlands: implications for screening.

OBJECTIVE: To identify low-risk groups among asylum seekers in the Netherlands that may be excluded from tuberculosis (TB) screening at entry or during follow-up. METHODS: A retrospective cohort study of medical records of asylum seekers entering the country between January 1994 and March 1997. RESULTS: Medical records were available for 46,424 of the 96,000 asylum seekers (48%) in this period. One hundred and three pulmonary TB cases were diagnosed at entry (prevalence 222/100,000). Risk factors were age >11 years, history of imprisonment and country of origin at war or with TB incidence >100/100,000. During a mean follow-up period of 10 months, 51 pulmonary TB cases were diagnosed (incidence 134/100,000 person-years). Risk factors were age >11 years, old lesions on entry X-ray, and country of origin whose asylum seekers had a prevalence of TB at entry >200/100,000. CONCLUSIONS: We conclude that 1) those with abnormal X-ray at entry should receive preventive therapy after exclusion of active TB, or undergo intensive follow-up, 2) periodic screening is not indicated for immigrants from countries whose asylum seekers have a low prevalence of pulmonary TB at entry, and 3) children <12 years can be excluded from screening.

Adolescent↗

PubMed2003

Exogenous re-infection as a cause of recurrent tuberculosis in a low-incidence area.

SETTING: Surveillance data from the National Tuberculosis Register for the period 1993-1997 complemented with DNA fingerprinting results of Mycobacterium tuberculosis isolates. OBJECTIVE: To estimate the proportion of disease attributable to recent re-infection among Dutch tuberculosis patients with reported tuberculosis infection or disease before 1981. DESIGN: Data from 1,547 Dutch patients diagnosed between 1994 and 1997 in the Netherlands were studied. Cases with reported tuberculosis infection or disease before 1981 were attributed to reactivation if their M. tuberculosis isolate was unclustered based on DNA fingerprinting or if they were the first case in a cluster, and to re-infection if they were clustered, but not as the first case. RESULTS: In total, 183 Dutch tuberculosis patients (12%) had reported tuberculosis infection or disease before 1981. Tuberculosis in 29 of these patients (16%) was attributed to recent re-infection. CONCLUSION: In this setting with a low tuberculosis incidence, approximately one in six new disease episodes among patients with previous tuberculosis infection or disease may be attributable to recent re-infection.

Adolescent↗

PubMed2003

Drug resistance among failure and relapse cases of tuberculosis: is the standard re-treatment regimen adequate?

OBJECTIVE: To determine acquired drug resistance among failure and relapse cases after treatment of new smear-positive tuberculosis. METHODS: A cohort of 2901 patients with new smear-positive tuberculosis was enrolled in Vietnam. Sputum samples were stored at enrolment. Upon failure or relapse, another sputum sample was collected. Both were cultured and underwent drug susceptibility testing and restriction fragment length polymorphism (RFLP) typing. RESULTS: Of 40 failure cases, 17 had multidrug resistance (MDR) at enrolment. At failure, 15 of the 23 (65%) patients without primary MDR had acquired MDR. Of 39 relapse cases and 143 controls, none had primary MDR. CONCLUSION: Primary drug resistance was a strong risk factor for failure and relapse and for acquiring further resistance. As 80% of failure cases had MDR, the standard re-treatment regimen appears inadequate for failure cases in this control programme with a very high cure rate among new cases.

Adolescent↗