Outcome of treatment of MDR-TB or drug-resistant patients treated with bedaquiline and delamanid: Results from a large global cohort

The World Health Organization (WHO) recommends countries introduce new anti-TB drugs in the treatment of multidrug-resistant tuberculosis. The aim of the study is to prospectively evaluate the effectiveness of bedaquiline (and/or delamanid)- containing regimens in a large cohort of consecutive TB patients treated globally. This observational, prospective study is based on data collected and provided by Global Tuberculosis Network (GTN) centres and analysed twice a year. All consecutive patients (including children/adolescents) treated with bedaquiline and/or delamanid were enrolled, and managed according to WHO and national guidelines. Overall, 52 centres from 29 countries/regions in all continents reported 883 patients as of January 31st 2021, 24/29 countries/regions providing data on 100% of their consecutive patients (10-80% in the remaining 5 countries). The drug-resistance pattern of the patients was severe (>30% with extensively drug-resistant -TB; median number of resistant drugs 5 (3-7) in the overall cohort and 6 (4-8) among patients with a final outcome). For the patients with a final outcome (477/883, 54.0%) the median (IQR) number of months of anti-TB treatment was 18 (13-23) (in days 553 (385-678)). The proportion of patients achieving sputum smear and culture conversion ranged from 93.4% and 92.8% respectively (whole cohort) to 89.3% and 88.8% respectively (patients with a final outcome), a median (IQR) time to sputum smear and culture conversion of 58 (30-90) days for the whole cohort and 60 (30-100) for patients with a final outcome and, respectively, of 55 (30-90) and 60 (30-90) days for culture conversion. Of 383 patients treated with bedaquiline but not delamanid, 284 (74.2%) achieved treatment success, while 25 (6.5%) died, 11 (2.9%) failed and 63 (16.5%) were lost to follow-up.

Pharmacokinetics of rifampicin in adult TB patients and healthy volunteers: a systematic review and meta-analysis

Objectives

The objectives of this study were to explore inter-study heterogeneity in the pharmacokinetics (PK) of orally administered rifampicin, to derive summary estimates of rifampicin PK parameters at standard dosages and to compare these with summary estimates for higher dosages.

Methods

A systematic search was performed for studies of rifampicin PK published in the English language up to May 2017. Data describing the C_max and AUC were extracted. Meta-analysis provided summary estimates for PK parameter estimates at standard rifampicin dosages. Heterogeneity was assessed by estimation of the I² statistic and visual inspection of forest plots. Summary AUC estimates at standard and higher dosages were compared graphically and contextualized using preclinical pharmacodynamic (PD) data.

Results

Substantial heterogeneity in PK parameters was evident and upheld in meta-regression. Treatment duration had a significant impact on the summary estimates for rifampicin PK parameters, with C_max 8.98 mg/L (SEM 2.19) after a single dose and 5.79 mg/L (SEM 2.14) at steady-state dosing, and AUC 72.56 mg·h/L (SEM 2.60) and 38.73 mg·h/L (SEM 4.33) after single and steady-state dosing, respectively. Rifampicin dosages of at least 25 mg/kg are required to achieve plasma PK/PD targets defined in preclinical studies.

Conclusions

Vast inter-study heterogeneity exists in rifampicin PK parameter estimates. This is not explained by the available modifying variables. The recommended dosage of rifampicin should be increased to improve efficacy. This study provides an important point of reference for understanding rifampicin PK at standard dosages as efforts to explore higher dosing strategies continue in this field.

Ebola, fragile health systems and tuberculosis care: a call for pre-emptive action and operational research

The Ebola outbreak that started in late 2013 is by far the largest and most sustained in history. It occurred in a part of the world where pre-existing health systems were already fragile, and these deteriorated further during the epidemic due to a large number of health worker deaths; temporary or permanent closure of health facilities; non-payment of health workers; intrinsic fear of contracting or being stigmatised by Ebola among the population, which negatively influenced health-seeking behaviour; enforced quarantine of Ebola-affected communities, restricting the access of vulnerable individuals to health facilities; and late response by the international community. There are also reports of drug and consumable stockouts due to deficiencies in the procurement and supply chain as a result of overriding Ebola-related priorities. Providing tuberculosis (TB) care and achieving favourable treatment outcomes require a fully functioning health system, accurate patient tracking and high patient adherence to treatment. Furthermore, as Ebola is easily transmitted through body fluids, the use of needles-essential for TB diagnosis and treatment-needs to be avoided during an outbreak. We highlight ways in which a sustained Ebola outbreak could jeopardise TB activities and suggest pre-emptive preventive measures while awaiting operational research evidence.

Highly successful treatment outcome of multidrug-resistant tuberculosis in the Netherlands, 2000-2009

SETTING

Resistance to the two key anti-tuberculosis drugs isoniazid and rifampicin is a characteristic of multidrug-resistant tuberculosis (MDR-TB). MDR-TB is a scourge requiring toxic, prolonged treatment and is associated with poor outcomes. The Netherlands is a country with a long-standing, integrated, well-resourced TB service where all patients are offered culture-confirmed diagnosis by a central reference laboratory.

OBJECTIVE

To assess the treatment outcomes of MDR-TB patients over a period of 10 years in The Netherlands.

DESIGN

Demographic, clinical and microbiological features of all patients with MDR-TB who started treatment in 2000-2009 in the Netherlands were analysed from national registry and patient records.

RESULTS

Characteristics of the 113 MDR-TB patients were as follows: male/female ratio 1.57, 96% foreign born, median age 29 years, 96 (85%) pulmonary TB, 56 (50%) smear-positive, 14 (12%) human immunodeficiency virus (HIV) co-infected. Of the 104 (92%) patients who started MDR-TB treatment, 86% had a successful outcome using a median of six active drugs; eight underwent pulmonary surgery. HIV negativity was associated with successful outcome (adjusted OR 2.1, 95%CI 1.1-3.8).

CONCLUSION

High success rates for MDR-TB treatment were achieved with close collaboration of all stakeholders, reaching the targets set for drug-susceptible TB. HIV remained an independent risk factor for unsuccessful treatment outcome.

An African woman with pulmonary cavities: TB or not TB?

Cavitary lung lesions in patients from developing countries are mostly caused by tuberculosis (TB). However, when TB cannot be confirmed, a primary lung abscess caused by anaerobic bacteria from the mouth should be considered, especially in patients with poor dentition. We present a case of a Sudanese woman with a cavitary lung lesion and severe gingivitis. Bulleidia extructa was isolated as a single pathogen from the pulmonary cavity.

Rapid diagnosis of pyrazinamide-resistant multidrug-resistant tuberculosis using a molecular-based diagnostic algorithm

There is an urgent need for rapid and accurate diagnosis of pyrazinamide-resistant multidrug-resistant tuberculosis (MDR-TB). No diagnostic algorithm has been validated in this population. We hypothesized that pncA sequencing added to rpoB mutation analysis can accurately identify patients with pyrazinamide-resistant MDR-TB. We identified from the Dutch national database (2007-11) patients with a positive Mycobacterium tuberculosis culture containing a mutation in the rpoB gene. In these cases, we prospectively sequenced the pncA gene. Results from the rpoB and pncA mutation analysis (pncA added to rpoB) were compared with phenotypic susceptibility testing results to rifampicin, isoniazid and pyrazinamide (reference standard) using the Mycobacterial Growth Indicator Tube 960 system. We included 83 clinical M. tuberculosis isolates containing rpoB mutations in the primary analysis. Rifampicin resistance was seen in 72 isolates (87%), isoniazid resistance in 73 isolates (88%) and MDR-TB in 65 isolates (78%). Phenotypic reference testing identified pyrazinamide-resistant MDR-TB in 31 isolates (48%). Sensitivity of pncA sequencing added to rpoB mutation analysis for detecting pyrazinamide-resistant MDR-TB was 96.8%, the specificity was 94.2%, the positive predictive value was 90.9%, the negative predictive value was 98.0%, the positive likelihood was 16.8 and the negative likelihood was 0.03. In conclusion, pyrazinamide-resistant MDR-TB can be accurately detected using pncA sequencing added to rpoB mutation analysis. We propose to include pncA sequencing in every isolate with an rpoB mutation, allowing for stratification of MDR-TB treatment according to pyrazinamide susceptibility.

Population pharmacokinetics and limited sampling strategy for first-line tuberculosis drugs and moxifloxacin

Therapeutic drug monitoring (TDM) of tuberculosis (TB) drugs currently focuses on peak plasma concentrations, yet total exposure [area under the 24-h concentration-time curve (AUC₀₋₂₄)] is probably most relevant to the efficacy of these drugs. We therefore assessed population AUC₀₋₂₄ data for all four first-line TB drugs (rifampicin, isoniazid, pyrazinamide and ethambutol) as well as moxifloxacin and developed limited sampling strategies to estimate AUC₀₋₂₄ values conveniently. AUC₀₋₂₄ and other pharmacokinetic (PK) parameters were determined following intensive PK sampling in two Dutch TB referral centres. Best subset selection multiple linear regression was performed to derive limited sampling equations. Median percentage prediction error and median absolute percentage prediction error were calculated via jackknife analysis to evaluate bias and imprecision of the predictions. Geometric mean AUC₀₋₂₄ values for rifampicin, isoniazid, pyrazinamide, ethambutol and moxifloxacin were 41.1, 15.2, 380, 25.5 and 33.6 hmg/L, respectively. Limited sampling at various fixed sampling points enabled an accurate and precise prediction of AUC₀₋₂₄ values of all drugs separately and simultaneously. In the absence of clinically validated target values for AUC₀₋₂₄, average AUC₀₋₂₄ values can be used as reference values in TDM. Limited sampling of AUC₀₋₂₄ is feasible in many settings and allows for TDM to be performed at a larger scale.

Mycobacterium genavense in the Netherlands: an opportunistic pathogen in HIV and non-HIV immunocompromised patients. An observational study in 14 cases

Mycobacterium genavense is an opportunistic non-tuberculous mycobacterium previously mostly associated with HIV-infected patients with CD4 counts below 100/μL. In this retrospective observational study of medical charts we studied all Dutch patients in whom M. genavense was detected between January 2002 and January 2010. Of the 14 patients identified, 13 (93%) showed clinically relevant M. genavense disease. All patients with M. genavense disease were severely immunocompromised, including HIV-infected patients, solid organ transplant recipients, those with chronic steroid use in combination with other immune modulating drugs, recipients of chemotherapy for non-Hodgkin lymphoma, and those with immunodeficiency syndromes. Two patients had non-disseminated pulmonary M. genavense disease. Of the 12 patients treated, eight (75%) showed a favourable outcome. Four patients died in this study, three despite treatment for M. genavense disease. We conclude that M. genavense is a clinically relevant pathogen in severely immunocompromised patients that causes predominantly disseminated disease with serious morbidity and mortality. M. genavense is increasingly seen among non-HIV immunocompromised patients.

Low-level rifampicin-resistant Mycobacterium tuberculosis strains raise a new therapeutic challenge

In an outbreak of multidrug-resistant tuberculosis, the outbreak strain had an Asp516Tyr rpoB gene mutation. Phenotypically, low-level rifampicin (RMP) resistance (minimum inhibitory concentration [MIC] 1-2 mg/l) was observed. Based on drug susceptibility test results, three patients were treated with 12-15 month rifabutin-based regimens and one with a 12-month RMP-based regimen. We retrospectively performed pharmacokinetic calculations to assess the potential for RMP treatment, from which we conclude that MICs for RMP up to 1 μg/ml may be safely overcome by applying 20 mg/kg RMP doses in treatment regimens.

Xpert MTB/RIF®, a novel automated polymerase chain reaction-based tool for the diagnosis of tuberculosis

There is an urgent need for new point of care tests for tuberculosis (TB). Xpert MTB/RIF® is a real-time polymerase chain reaction-based system that detects Mycobacterium tuberculosis DNA and rifampicin (RMP) resistance modulating mutations directly from clinical samples in 2 h. The sensitivity for detecting M. tuberculosis in culture-positive samples was 93.8% (60/64) and exceeded smear microscopy (40/64, 62.5%). The specificity for detecting M. tuberculosis was 92.0% (23/25) and for RMP resistance it was 100% (8/8). The test is simple to conduct and requires basic sputum handling facilities only. These characteristics render it a promising close-to-patient test for TB in various settings.

Re-analysis of 178 previously unidentifiable Mycobacterium isolates in the Netherlands in 1999-2007

Nontuberculous mycobacteria (NTM) that cannot be identified to the species level by reverse line blot hybridization assays and sequencing of the 16S rRNA gene comprise a challenge for reference laboratories. However, the number of 16S rRNA gene sequences added to online public databases is growing rapidly, as is the number of Mycobacterium species. Therefore, we re-analysed 178 Mycobacterium isolates with 53 previously unmatched 16S rRNA gene sequences, submitted to our national reference laboratory in 1999–2007. All sequences were again compared with the GenBank database sequences and the isolates were re-identified using two commercially available identification kits, targeting separate genetic loci. Ninety-three out of 178 isolates (52%) with 20 different 16S rRNA gene sequences could be assigned to validly published species. The two reverse line blot assays provided false identifications for three recently described species and 22 discrepancies were recorded in the identification results between the two reverse line blot assays. Identification by reverse line blot assays underestimates the genetic heterogeneity among NTM. This heterogeneity can be clinically relevant because particular sub-groupings of species can cause specific disease types. Therefore, sequence-based identification is preferable, at least at the reference laboratory level, although the exact targets needed for clinically useful results remain to be established. The number of NTM species in the environment is probably so high that unidentifiable clinical isolates should be given a separate species status only if this is clinically meaningful.

Serum 25-hydroxy-vitamin D3 concentrations increase during tuberculosis treatment in Tanzania

SETTING

Vitamin D deficiency is associated with susceptibility to active tuberculosis (TB) in many settings. In vitro studies and studies on human volunteers showed that two of the first-line anti-tuberculosis drugs, isoniazid and rifampicin, reduce 25-hydroxy vitamin D (25[OH]D) concentrations.

OBJECTIVE

To study changes in vitamin D status during treatment of Tanzanian hospitalised patients with pulmonary TB (PTB).

DESIGN

We compared serum 25[OH]D concentrations in 81 Tanzanian PTB patients before and after 2 months of treatment.

RESULTS

Median serum 25[OH]D concentrations increased from 91 nmol/l at baseline to 101 nmol/l after 2 months of TB treatment (median increase 6.0 nmol/l, IQR -0.7-25.0, P = 0.001). Median serum parathyroid hormone concentrations increased from 1.6 to 2.0 pmol/l (median increase 0.46, IQR -0.2-1.1, P < 0.001).

CONCLUSION

25[OH]D serum concentrations increased during the first 2 months of TB treatment in 81 PTB patients in northern Tanzania. Improved dietary intake and increased sunlight exposure may have contributed to the increased 25[OH]D concentrations.

The changing pattern of clinical Mycobacterium avium isolation in the Netherlands

SETTING

National Mycobacteria Reference Laboratory, The Netherlands.

OBJECTIVE

To assess the role of factors other than laboratory improvements in the increasing frequency of isolation of non-tuberculous mycobacteria (NTM) in the Netherlands; laboratory improvements are often considered key factors in this increase.

DESIGN

Laboratory database study. All clinically isolated NTM referred to the national reference laboratory between January 2000 and January 2007 were retrieved from the laboratory database and categorised by species, patient age group and sample origin. Data were compared with national demographic data.

RESULTS

Clinical Mycobacterium avium isolates accounted for most of the increase in referred NTM. The number of respiratory M. avium samples in patients aged >40 years increased over time. This age group increased in size during the study. In this age group, the prevalence of chronic obstructive pulmonary disease (COPD) increased during the study period. M. avium isolation from lymph nodes in children remained stable, whereas extra-pulmonary M. avium isolation in the middle age group, including human immunodeficiency virus associated bloodstream isolates, decreased.

CONCLUSIONS

The increasing NTM notification in the Netherlands is unlikely to have been a result of laboratory improvements alone: the ageing population with an increasing prevalence of COPD is likely as important. Environmental characteristics may specifically favour M.avium.

Surgical treatment of non-tuberculous mycobacterial lung disease: strike in time

SETTING

The Netherlands.

OBJECTIVE

To describe our experiences with the adjunctive role and benefits of surgery for lung disease due to non-tuberculous mycobacteria (NTM), specifically addressing its indications and timing.

DESIGN

Retrospective medical file review of eight patients who underwent surgical treatment for NTM lung disease in the period January 2000 to January 2009, and review of the available literature.

RESULTS

Therapy-resistant cavitary NTM disease was the most frequent indication for surgery; two patients underwent pneumonectomy for an infected destroyed lung. Mycobacterium avium was the most common causative agent. Surgery resulted in culture conversion in seven patients; one patient died 2 months after pneumonectomy. No relapses have been noted in the other seven after an average of 19 months of follow-up.

CONCLUSIONS

Adjunctive surgical treatment for NTM lung disease yields encouraging results, similar to previously published case series. Careful patient selection, based on extent and type of disease as well as on cardiopulmonary fitness, is important. Potential benefits of surgery should be considered for every individual patient in whom NTM lung disease is diagnosed and re-evaluated after 6 months of treatment. Where possible, surgery should be pursued and conducted in a timely fashion.

Community vs. facility-based directly observed treatment for tuberculosis in Tanzania's Kilimanjaro Region

SETTING

Kilimanjaro Region, northern Tanzania.

OBJECTIVE

To assess the effect of the introduction of the patient-centred tuberculosis treatment (PCT) approach-which allows tuberculosis (TB) patients to choose between community and facility-based directly observed treatment (DOT)-on treatment outcomes, and to analyse factors that contribute to opting for community DOT.

DESIGN

Retrospective analysis of treatment outcomes of TB patients registered in the Kilimanjaro Region in 2007, differentiating between patients under community vs. facility-based DOT and taking into account demographic factors, disease classification, TB diagnosis and human immunodeficiency virus (HIV) status.

RESULTS

Data from 2769 TB patients were analysed. Treatment success rates were respectively 81% and 70% in patients under community vs. facility-based DOT (P < 0.001). Cure rates were respectively 73% and 72% in smear-positive pulmonary TB patients under community vs. facility-based DOT (P = 0.62). Women, children, patients residing in districts other than Hai, patients with newly diagnosed TB and patients with smear-negative pulmonary TB were most likely to be under community DOT.

CONCLUSION

The PCT approach was shown to be effective in terms of treatment outcomes. Treatment success rates were higher in patients who opted for community DOT than in patients who chose facility-based DOT (all cases), and were similar in smear-positive pulmonary TB patients under community or facility-based DOT.

Proposal to elevate Mycobacterium avium complex ITS sequevar MAC-Q to Mycobacterium vulneris sp. nov

The Mycobacterium avium complex (MAC) consists of four recognized species, Mycobacterium avium, Mycobacterium colombiense, Mycobacterium intracellulare and Mycobacterium chimaera, and a variety of other strains that may be members of undescribed taxa. We report on two isolates of a scotochromogenic, slowly growing, non-tuberculous Mycobacterium species within the M. avium complex from a lymph node and an infected wound after a dogbite of separate patients in The Netherlands. The extrapulmonary infections in immunocompetent patients suggested a high level of virulence. These isolates were characterized by a unique nucleotide sequence in the 16S rRNA gene, 99% similar to Mycobacterium colombiense, and the MAC-Q 16S-23S internal transcribed spacer (ITS) sequence. Sequence analyses of the hsp65 gene revealed 97% similarity to M. avium. The rpoB gene sequence was 98% similar to M. colombiense. Phenotypically, the scotochromogenicity, positive semi-quantitative catalase and heat-stable catalase tests, negative tellurite reductase and urease tests and susceptibility to hydroxylamine and oleic acid set these isolates apart from related species. High-performance liquid chromatography analysis of cell-wall mycolic acid content revealed a unique pattern, related to that of M. avium and M. colombiense. Together, these findings supported a separate species status within the Mycobacterium avium complex. We propose elevation of scotochromogenic M. avium complex strains sharing this 16S gene and MAC-Q ITS sequence to separate species status, for which the name Mycobacterium vulneris sp. nov. is proposed. The type strain is NLA000700772T (=DSM 45247T=CIP 109859T).

Clinical relevance of non-tuberculous mycobacteria isolated in the Nijmegen-Arnhem region, The Netherlands

BACKGROUND

The frequency of clinical isolation of non-tuberculous mycobacteria (NTM) in the Netherlands is increasing, but its clinical relevance is often uncertain.

OBJECTIVE

To assess the frequency and clinical relevance of isolation of NTM in four associated hospitals in a single region in the Netherlands.

METHODS

Medical files of all patients from whom NTM were isolated between January 1999 and January 2005 were reviewed retrospectively. Diagnostic criteria for non-tuberculous mycobacterial disease published by the American Thoracic Society (ATS) were used to determine clinical relevance.

RESULTS

232 patients were found, from whom NTM were isolated from the respiratory tract in 91% of cases. Patients were mostly white men, with an average age of 60 years and pre-existing pulmonary disease. Fifty-three of 212 patients (25%) with pulmonary isolates met the ATS diagnostic criteria for pulmonary NTM disease; this percentage differed by species. Most patients were treated with rifampicin, ethambutol and clarithromycin. Treatment outcome for pulmonary NTM disease was suboptimal but differed by species: overall, improvement was seen in 67% of treated patients, but in only 50% of those with pulmonary M avium disease. Lymphadenitis was the most common extrapulmonary disease type.

CONCLUSIONS

Twenty-five per cent of all patients with pulmonary NTM isolates met the ATS criteria. Clinical relevance differs by species. NTM isolation increases over time. Species distribution differs from that of neighbouring countries and the M avium complex isolates have traits different from those reported in the USA. Adherence to diagnostic and treatment guidelines can be improved.

Aetiology and presentation of HIV/AIDS-associated pulmonary infections in patients presenting for bronchoscopy at a referral hospital in northern Tanzania

OBJECTIVES

To determine the aetiological agents of pulmonary infections in HIV-infected Tanzanians and to correlate the causative agents with clinical, radiographic features, and mortality.

DESIGN

A prospective study.

SETTING

Kilimanjaro Christian Medical Centre (KCMC), Tanzania.

SUBJECTS

Bronchoalveolar lavage fluid (BAL) were obtained from 120 HIV infected patients with pulmonary infections. BAL for causative agents was analysed and correlated with clinical and radiographic features, and one-month outcome.

RESULTS

Causative agents were identified in 71 (59.2%) patients and in 16 of these patients, multiple agents were found. Common bacteria were identified in 35 (29.2%) patients, Mycobacterium tuberculosis in 28 (23.3%), Human Herpes Virus 8 (HHV8) in 12 (10%), Pneumocystis jiroveci in nine (7.5%) and fungi in five (4.2%) patients. Median CD4 T cell count of the patients with identified causes was 47 cells/microl (IQR 14-91) and in the 49 patients with undetermined aetiology was 100 cells/ microl (IQR 36-188; p = 0.01). Micronodular chest radiographic lesions were associated with presence of M. tuberculosis (p = 0.002). The one-month mortality was 20 (16.7%). The highest mortality was associated with HHV8 (41.7%) and M. tuberculosis (32.1%). Mortality in patients with undetermined aetiology was 11.3%. No death occurred in patients with PCP.

CONCLUSION

In this population of severely immunosuppressed HIV-infected patients with pulmonary infection a variety of causative agents was identified. Micronodular radiographic lesions were indicative of TB. High mortality was associated with M. tuberculosis or HHV8. No death occurred in patients with P. jiroveci infection.

Second-line drug resistance in multidrug-resistant tuberculosis cases of various origins in the Netherlands

SETTING

The Netherlands.

OBJECTIVE

To investigate the frequency of resistance to second-line drugs among multidrug-resistant tuberculosis (MDR-TB) cases and its correlation with patients' geographic origin.

DESIGN

Retrospective laboratory database study of multidrug-resistant Mycobacterium tuberculosis complex strains isolated in the Netherlands between January 1993 and October 2007.

RESULTS

We found 153 patients with MDR-TB, of whom 18 (12%) were native Dutch. Complete second-line drug susceptibility testing was performed for 131 MDR-TB patients. Resistance to second-line drugs was noted in primary samples of 28 (21%) MDR-TB patients. Resistance to a single second-line drug was most frequent (24/28 [86%]; 9 to prothionamide [PTH], 6 to para-aminosalicylic acid, 4 to amikacin [AMK], 4 to ciprofloxacin and 1 to cycloserine). Four MDR-TB patients had strains resistant to multiple second-line drugs; two were extensively drug-resistant M. bovis. In MDR-TB patients of European and Central Asian origin, resistance to second-line drugs was most frequent and involved the widest range of drugs. PTH resistance was frequent among African and American MDR-TB patients, while AMK resistance was frequent among South-East Asians.

CONCLUSION

Resistance to second-line drugs is infrequent among MDR-TB patients in the Netherlands. Most second-line drug resistance is recorded among immigrants, with substantial differences in second-line drug resistance in MDR-TB patients originating from different geographical areas.

The rising incidence and clinical relevance of Mycobacterium malmoense: a review of the literature

The incidence of Mycobacterium malmoense infections compared to other non-tuberculous mycobacteria (NTM) has increased since 1980, especially in northern Europe. Based on various epidemiological and clinical reports outside northern Europe, there is a wide distribution of these infections. Infections with M. malmoense cause pulmonary disease comparable with tuberculosis (TB). The main extra-pulmonary disease type is paediatric cervical lymphadenitis. M. malmoense isolates are clinically significant in about 70-80% of patients. Like other NTM infections, M. malmoense is often found in patients with chronic obstructive pulmonary disease (COPD) and may cause serious morbidity and mortality when inadequately treated. The best treatment consists of a 2-year regimen with rifampicin and ethambutol. The literature on infections with M. malmoense is reviewed with respect to epidemiology, clinical presentation, treatment and outcome.

[Characteristics and treatment of tuberculosis patients in Dekkerswald, 2000-2005]

OBJECTIVE

To describe the patient population in Dekkerswald, Nijmegen, one of two tuberculosis (TB) centres in The Netherlands.

DESIGN

Descriptive, retrospective study.

METHOD

Examination of medical records for all TB patients hospitalised between 2000 and 2005, including demographic, social, clinical and follow-up data.

RESULTS

Data from 166 patients were analysed. Tertiary referrals accounted for 98% of all hospitalisations. Most patients (68%) were referred for clinical reasons, and 32% were referred for social reasons. Drug resistance was encountered in 23% of patients; 9% had multidrug-resistant TB. Ten percent of patients were seropositive for HIV. Toxicity and side-effects of treatment often led to changes in treatment (40%). Patients had pulmonary TB (59%), extrapulmonary TB (23%) or both (17%). Overall, 141 patients (85%) completed treatment. The TB-related mortality rate was 5%.

CONCLUSION

In Dekkerswald, there is a selected patient population that is characterised by drug-resistance, comorbidity, side-effects, extrapulmonary disease and social issues. Due to the low prevalence of TB in The Netherlands, knowledge and experience regarding complex types of TB are limited. Centralisation of patient care is important to preserve and optimise this expertise.

Short communication: Antituberculosis drug-induced hepatotoxicity is unexpectedly low in HIV-infected pulmonary tuberculosis patients in Malawi

The proportion of patients with antituberculosis drug-induced hepatotoxicity (ATDH) was unexpectedly low during a trial on cotrimoxazole prophylaxis in Malawian HIV-positive pulmonary tuberculosis patients. About 2% of the patients developed grade 2 or 3 hepatotoxicity during tuberculosis (TB) treatment, according to WHO definitions. Data on ATDH in sub-Saharan Africa are limited. Although the numbers are not very strong, our trial and other papers suggest that ATDH is uncommon in this region. These findings are encouraging in that hepatotoxicity may cause less problem than expected, especially in the light of combined HIV/TB treatment, where drug toxicity is a major cause of treatment interruption.

Pharmacokinetics of adjusted-dose lopinavir-ritonavir combined with rifampin in healthy volunteers

Coadministration of lopinavir-ritonavir, an antiretroviral protease inhibitor, at the standard dose (400/100 mg twice a day [BID]) with the antituberculous agent rifampin is contraindicated because of a significant pharmacokinetic interaction due to induction of cytochrome P450 3A by rifampin. In the present study, two adjusted-dose regimens of lopinavir-ritonavir were tested in combination with rifampin. Thirty-two healthy subjects participated in a randomized, two-arm, open-label, multiple-dose, within-subject controlled study. All subjects were treated with lopinavir-ritonavir at 400/100 mg BID from days 1 to 15. From days 16 to 24, the subjects in arm 1 received lopinavir-ritonavir at 800/200 mg BID in a dose titration, and the subjects in arm 2 received lopinavir-ritonavir at 400/400 mg BID in a dose titration. Rifampin was given at 600 mg once daily to all subjects from days 11 to 24. The multiple-dose pharmacokinetics of lopinavir, ritonavir, and rifampin were assessed. Twelve of 32 subjects withdrew from the study. For nine subjects lopinavir-ritonavir combined with rifampin resulted in liver enzyme level elevations. Pharmacokinetic data for 19 subjects were evaluable. Geometric mean ratios for the lopinavir minimum concentration in serum and the maximum concentration in serum (C(max)) on day 24 versus that on day 10 were 0.43 (90% confidence interval [CI], 0.19 to 0.96) and 1.02 (90% CI, 0.85 to 1.23), respectively, for arm 1 (n = 10) and 1.03 (90% CI, 0.68 to 1.56) and 0.93 (90% CI, 0.81 to 1.07), respectively, for arm 2 (n = 9). Ritonavir exposure increased from days 10 to 24 in both arms. The geometric mean C(max) of rifampin was 13.5 mg/liter (day 24) and was similar between the two arms. Adjusted-dose regimens of lopinavir-ritonavir in combination with therapeutic drug monitoring and monitoring of liver function may allow concomitant use of rifampin.

[Tuberculosis and HIV coinfection in three patients: the possibilities for simultaneous treatment]

Three patients received simultaneous treatment for tuberculosis and HIV: a 23-year-old woman and a 33-year-old man who were asylum seekers from Africa and a 45-year-old woman who was an intravenous drug addict. During the treatment with antiretroviral and anti-tuberculous drugs, several problems arose: drug interactions (between rifampicine and protease inhibitors/non-nucleoside reverse transcriptase inhibitors), side effects, non-compliance and immune reconstitution reactions. These problems were solved either by temporary withdrawal of the medication or by substituting other drugs. There are a number of possible treatment strategies that minimise the risks. Despite the potential problems, in patients with advanced HIV infection, antiretroviral treatment should not be delayed until after the end of the tuberculosis treatment.

Opsonic phagocytosis of Streptococcus pneumoniae by alveolar macrophages is not impaired in human immunodeficiency virus-infected Malawian adults

Streptococcus pneumoniae is a major cause of pneumonia, bacteremia, and meningitis, especially among adults infected with the human immunodeficiency virus (HIV). Alveolar macrophages (AMs) are critical components of cellular defense against bacterial infection and are both infected and affected by HIV. In this study, AMs obtained at bronchoscopy from 44 Malawian adults (24 HIV positive and 20 HIV negative) were exposed in vitro to opsonized S. pneumoniae and coagulase-negative staphylococci. AMs from HIV-positive and -negative volunteers showed no significant difference in binding to or internalization of either S. pneumoniae or coagulase-negative staphylococci. In HIV-positive subjects, the presence of detectable HIV in lung fluid was not associated with AM impairment. AMs from HIV-infected adults did not exhibit impaired pneumococcal phagocytosis in the assay used. This suggests that an alternative mechanism of susceptibility is operating in these individuals.

Gender differences in relation to sputum submission and smear-positive pulmonary tuberculosis in Malawi

OBJECTIVE

To examine gender differences in sputum submission and sputum smear positivity.

METHODS

Laboratory registers in all diagnostic units in eight districts in Malawi were examined for the years 1995 and 1996.

RESULTS

During a 12-month period (averaged between 1995 and 1996), 26,624 new TB suspects submitted sputum samples, 3282 of which (12.3%) were smear-positive. Significantly more males submitted sputum (52%) compared with females (48%), and significantly more males (53%) were smear-positive compared with females (47%, P < 0.05). Rates of sputum submission per 100,000 adults were also significantly higher for males (1203) than females (1032).

CONCLUSION

In Malawi, fewer females are submitting sputum samples and are being diagnosed with smear-positive TB compared with males.

Care seeking behaviour and diagnostic processes in patients with smear-positive pulmonary tuberculosis in Malawi

SETTING

Government hospitals in five districts in Malawi.

OBJECTIVE

To determine care seeking behaviour and diagnostic processes in patients newly diagnosed with smear-positive pulmonary tuberculosis (PTB).

DESIGN

Structured questionnaires completed by interview between January to September 1998.

RESULTS

During the study period 1,518 patients were registered with PTB, of whom 1,099 (72%) were interviewed. The median delay between onset of cough and diagnosis was 8 weeks. There was a variable pattern of care seeking behaviour, with 70% of patients initially visiting a place of orthodox medical care and 30% visiting traditional healers, grocery shops, etc. Of these, 867 (79%) patients had one or more subsequent contacts for help, with these visits targeted more to orthodox medical care. At all stages, antibiotics resulted in symptomatic improvement in up to 40% of cases. There was a median time of 7 weeks between cough and first submission of sputum specimens. Almost all patients received sputum smear results after a median length of 4 days; 474 (43%) of patients were only aware of their diagnosis at the time of receiving smear results, this observation being significantly associated with lack of schooling and not knowing another person with TB.

CONCLUSION

More needs to be done to educate communities and non-orthodox care providers about the diagnosis and treatment of TB.

Viability of stored sputum specimens for smear microscopy and culture

A laboratory study was performed to determine how long sputum specimens from smear-positive tuberculosis patients can be stored at room temperature or in the refrigerator and retain a positive acid-fast bacilli (AFB) smear or a positive mycobacterial culture. Sputum samples from 30 patients were examined up to 4 weeks and samples from 13 patients examined up to 8 weeks. Provided samples had not dried out, all sputum smears remained AFB positive up to 4 and 8 weeks. In both patient groups, at 4 weeks 37-39% of specimens at room temperature grew mycobacteria compared with 54-67% of specimens stored in the refrigerator. These results have implications for tuberculosis programme policy.

The diagnosis of smear-negative pulmonary tuberculosis: the practice of sputum smear examination in Malawi

SETTING

Forty hospitals in Malawi (3 central, 22 district and 15 mission) performing smear microscopy and registering tuberculosis patients.

OBJECTIVE

To determine, in patients aged 15 years or above, 1) the proportion with smear-negative pulmonary tuberculosis (PTB) who had sputum smears examined, 2) the number of sputum smears examined per patient, and 3) the proportion of patients registered with smear-positive and smear-negative PTB.

DESIGN

Data collection during three 6-month periods, from January 1997 to June 1998, using tuberculosis registers, laboratory sputum registers and quarterly reports.

RESULTS

Of 6301 smear-negative PTB patients, 84% had sputum smears examined, the rate increasing from 76% in January-June 1997, to 85% in July-December 1997, to 89% in January-June 1998. Of patients who submitted sputum (where the number of smears was recorded), 99% had two or more smears examined and 93% had three smears examined. In district and mission hospitals performance improved over time, while in central hospitals results were more variable. During the same 18-month period 21 422 patients aged 15 years or more were registered with PTB: 59% with smear-positive PTB and 41% with smear-negative PTB; this pattern was similar in each 6-month period.

CONCLUSION

The study suggests that it is reasonable to aim for a target of 90% or more of smear-negative PTB patients having sputum smears examined.

Treatment outcome of patients with smear-negative and smear-positive pulmonary tuberculosis in the National Tuberculosis Control Programme, Malawi

National tuberculosis control programmes (NTPs) in sub-Saharan Africa do not routinely record or report treatment outcome data on smear-negative pulmonary tuberculosis (PTB) patients. Twelve-month treatment outcome on patients with smear-negative PTB registered in all district and mission hospitals in Malawi during the year 1995 was collected, and was compared with 8-month treatment outcome in smear-positive PTB patients registered during the same period. Of 4240 patients with smear-negative PTB, 35% completed treatment, 25% died, 9% defaulted and 7% were transferred to another district with no treatment outcome results available. In 24% of patients treatment cards were lost and treatment outcome was unknown. These results were significantly inferior to those obtained in 4003 patients with smear-positive PTB in whom 72% completed treatment, 20% died, 4% defaulted, 2% were transferred and 1% had positive smears at the end of treatment. These differences between patients with smear-negative and smear-positive PTB were similar when analysed by sex and by most age-groups. Higher mortality rates in patients with smear-negative PTB are probably attributable to advanced HIV-related immunosuppression, and higher default and treatment unknown rates probably reflect the lack of attention paid by TB programme staff to this group of patients. As a result of this country-wide study the Malawi NTP has started to record routinely the treatment outcomes of smear-negative TB patients and has set treatment completion targets of 50% or higher for this group of patients.

True status of smear-positive pulmonary tuberculosis defaulters in Malawi

The article reports the results of a study to determine the true outcome of 8 months of treatment received by smear-positive pulmonary tuberculosis (PTB) patients who had been registered as defaulters in the Queen Elizabeth Central Hospital (QECH) and Mlambe Mission Hospital (MMH), Blantyre, Malawi. The treatment outcomes were documented from the tuberculosis registers of all patients registered between 1 October 1994 and 30 September 1995. The true treatment outcome for patients who had been registered as defaulters was determined by making personal inquiries at the treatment units and the residences of patients or relatives and, in a few cases, by writing to the appropriate postal address. Interviews were carried out with patients who had defaulted and were still alive and with matched, fully compliant PTB patients who had successfully completed the treatment to determine the factors associated with defaulter status. Of the 1099 patients, 126 (11.5%) had been registered as defaulters, and the true treatment outcome was determined for 101 (80%) of the latter; only 22 were true defaulters, 31 had completed the treatment, 31 had died during the treatment period, and 17 had left the area. A total of 8 of the 22 true defaulters were still alive and were compared with the compliant patients. Two significant characteristics were associated with the defaulters; they were unmarried; and they did not know the correct duration of antituberculosis treatment. Many of the smear-positive tuberculosis patients who had been registered as defaulters in the Blantyre district were found to have different treatment outcomes, without defaulting. The quality of reporting in the health facilities must therefore be improved in order to exclude individuals who are not true defaulters.

Tuberculosis in health care workers in Malawi

Although sub-Saharan Africa has the highest rates of tuberculosis (TB) and human immunodeficiency virus (HIV) infection in the world, the rates of TB amongst its health care workers (HCWs) are poorly documented. We therefore conducted a country-wide investigation. All district/government and mission hospitals in Malawi that diagnose and care for TB patients were visited in order to obtain information on hospital-based HCWs and their incidence of TB in 1996. Hospital TB case loads, country-wide TB notification numbers and national population estimates for 1996 were obtained, which enabled TB case notification rates to be calculated. In 1996, 108 (3.6%) of 3042 HCWs from 40 hospitals were registered and treated for TB: 22 with smear-positive pulmonary TB (PTB), 40 with smear-negative PTB and 46 with extrapulmonary TB. The overall case fatality rate was 24%. Compared with the adult general population aged > or = 15 years, the relative risk [95% confidence interval (CI)] in HCWs of all types of TB was 11.9 [9.8-14.4], of smear-positive PTB 5.9 [3.9-9.0], of smear-negative PTB 13.0 [9.5-17.7] and of extrapulmonary TB 18.4 [13.8-24.6], P < 0.05. The 1996 hospital TB case load ranged from 29 to 915: there were no cases of TB in HCWs in hospitals whose case load was < or = 100 patients, while the TB case rate among HCWs was similar in hospitals with annual case loads of 101-300 or > 300. The annual risk of TB was high among all categories of HCW, especially clinical officers. This study shows a high rate of TB in HCWs in Malawi, and emphasizes the need for practical and affordable control measures for the protection of HCWs from TB in low-income countries.

Management of pulmonary tuberculosis suspects with negative sputum smears and normal or minimally abnormal chest radiographs in resource-poor settings

SETTING

Queen Elizabeth Central Hospital, Blantyre, Malawi.

OBJECTIVES

1) To determine the proportion of pulmonary tuberculosis (PTB) suspects with negative sputum smears and a normal/minimally abnormal chest radiograph (CXR) who are culture-positive for Mycobacterium tuberculosis, and 2) to determine how many develop smear or radiographic evidence of PTB (TB CXR) during follow-up.

METHODS

PTB suspects with negative sputum smears and a normal/minimally abnormal CXR were given a second course of antibiotics and followed up at 3-week intervals over 3 months with repeat sputum smears and chest radiography.

RESULTS

Of 79 patients (38 men and 41 women, mean age 33 years) with negative smears and a normal/minimally abnormal CXR, 16 (21%) were culture-positive for M. tuberculosis. Of 15 culture-positive patients who were alive and attended follow-up, seven (47%) developed a TB-CXR by 3 months. Of 41 culture-negative patients who were alive and attended follow-up, 13 (32%) developed a TB-CXR, including one patient who became sputum smear-positive. TB-CXRs were found only in patients with a cough.

CONCLUSION

TB suspects with negative smears and normal/minimally abnormal CXRs in high human immunodeficiency virus (HIV) prevalent countries should be given a second course of antibiotics. If cough improves, patients can be advised not to return for further follow-up. If cough continues, patients should return for further follow-up with sputum smear examination and chest radiography. Approximately 50% of those who have culture-positive PTB will develop a TB-CXR by 3 months and can be identified if radiographic facilities are available.

No effects of high-dose omeprazole in patients with severe airway hyperresponsiveness and (a)symptomatic gastro-oesophageal reflux

Acid gastro-oesophageal reflux may aggravate respiratory symptoms in patients with asthma and chronic obstructive pulmonary disease (COPD) by increasing airway hyperresponsiveness through vagally-mediated pathways. We wanted to determine whether elimination of acid reflux could improve symptoms in such patients. In a randomized, double-blind, placebo-controlled study, 36 allergic and nonallergic subjects (17 males and 19 females, mean age 52 yrs), with airway obstruction and severe airway hyperresponsiveness despite maintenance treatment with an inhaled corticosteroid and with increased acid gastro-oesophageal reflux, were treated either with omeprazole, 40 mg b.i.d., or placebo for 3 months. Primary endpoints were: airway hyperresponsiveness, as determined by the provocative concentration of methacholine producing a 20% fall in forced expiratory volume in one second (PC20); and airway obstruction. Secondary endpoints were: peak expiratory flow variability; reversibility to inhaled ipratropium bromide as a parameter of vagal activity; asthma symptoms scores; and medication used. Reflux was measured by 24 h ambulatory intraoesophageal pH measurement. Omeprazole, 40 mg b.i.d., for 3 months had no beneficial effect on any of the pulmonary parameters, despite its profound effect on acid reflux and improvement of reflux symptoms scores, compared to placebo. The results of this study do not support a role for intensive antireflux therapy to improve pulmonary symptoms and function in patients with asthma and chronic obstructive pulmonary disease, who have severe airway hyperresponsiveness despite maintenance treatment with inhaled corticosteroids.

Prevalence of tuberculosis in TB suspects with short duration of cough

The prevalence of pulmonary tuberculosis (PTB) in patients with short duration of cough was determined. Ninety-eight adult out-patients (60 men, 38 women; mean age 32 years) at Queen Elizabeth Central Hospital, Blantyre, Malawi, who had cough for 1-3 weeks which was unresponsive to a course of antibiotics, were successfully screened by microscopy and culture of 2 or 3 sputum specimens and chest radiography; 34 (35%) had PTB. Ten patients were sputum smear-positive and 24 were smear-negative and culture-positive. There was no difference in age, gender or clinical features of general illness, respiratory disease and HIV-related disease between patients with PTB and those with no evidence of PTB. Nine patients (26%) with microbiologically confirmed tuberculosis (TB) had chest radiograph abnormalities consistent with TB, compared with 5 (8%) of patients with no microbiological evidence of TB. Certain classes of patients with a short history of cough would benefit from PTB screening strategies with the emphasis on sputum examination rather than chest radiography, which is unreliable in such patients. The classes include (i) patients with other features of TB whose cough has not improved with antibiotic therapy, (ii) seriously ill patients, and (iii) patients in high risk institutions such as prisons and refugee camps.

Traditional healers and pulmonary tuberculosis in Malawi

SETTING

Queen Elizabeth Central Hospital (QECH) and Blantyre district, Malawi.

OBJECTIVE

To investigate the use that tuberculosis (TB) patients in Malawi make of traditional healers and traditional medicine.

DESIGN

A questionnaire study was carried out on 89 smear-positive pulmonary TB patients admitted to QECH. Seven traditional healers in Blantyre were also interviewed about their knowledge, attitudes and practice of patients whom they considered to have TB.

RESULTS

Of the 89 patients, 33 (37%) visited a traditional healer before seeking regular medical care. Patients spent a median length of 4 weeks with the traditional healer. During this time, 24 patients did not improve or deteriorated while on traditional treatment. No patient was referred to the medical services by the traditional healer. All traditional healers claimed to know about TB. Four said they would refer a patient to hospital if their treatment was not curative. In 1995, six traditional healers claimed to have cured 116 patients with TB.

CONCLUSION

It is important to involve traditional healers in the educational activities of the National TB Control Programme. These healers need to be taught to recognise and refer patients with TB, whom they should not treat, but at the same time be encouraged to administer safe treatments for conditions which are more amenable to their practice.

Case finding for pulmonary tuberculosis, Queen Elizabeth Central Hospital, Blantyre, Malawi

SETTING

Queen Elizabeth Central Hospital, Malawi.

OBJECTIVE

To evaluate the investigation of patients with cough who attend out-patient services and the adherence to recommended diagnostic protocols.

DESIGN

Two operational studies in 1995: 1) an audit of management of patients presenting to non-fee-paying out-patient services (OPD) with cough, and 2) an audit of the laboratory sputum register and the OPD cough register. The annual number of out-patient attendances was also recorded.

RESULTS

Of 2381 patients seen by OPD medical assistants, 438 (18.4%) complained of cough: 303 for < 3 weeks and 135 for > or = 3 weeks. Sputum smear examinations were requested in 97 patients, 79 (58.5%) with long duration and 18 (5.9%) with short duration of cough. Between May and December 1995, of the 1668 OPD patients who had sputum results in the laboratory register, 1392 (83%) had sputum results in the cough register. Of patients listed in the cough register, 98% collected their sputum smear results. In 1995, there were 395,439 OPD attendances; data extrapolation suggests that about 15,000 patients should have had sputum examined instead of the 2337 listed in the laboratory register.

CONCLUSION

A large burden is imposed on out-patient services by patients with cough. Despite recommended protocols, this investigation suggests deficiencies in case detection which require further study.