Updating the approaches to define susceptibility and resistance to anti-tuberculosis agents: implications for diagnosis and treatment

Approximately 85 000 deaths globally in 2019 were due to drug-resistant tuberculosis (TB), which corresponds to 7% of global deaths attributable to bacterial antimicrobial resistance [1]. Yet concerns have been mounting that drug-resistant TB was being underestimated because the approaches to define susceptibility and resistance to anti-TB agents had not kept up with those used for other major bacterial pathogens [2–9]. Here, we outline the recent, evidence-based initiatives spearheaded by the World Health Organization (WHO) and others to update breakpoints (traditionally referred to as critical concentrations (CCs)) that are used for phenotypic antimicrobial susceptibility testing (AST), also called drug susceptibility testing in the TB literature.

Inappropriately high breakpoints have resulted in systematic false-susceptible AST results to anti-TB drugs. MIC, PK/PD and clinical outcome data should be combined when setting breakpoints to minimise the emergence and spread of antimicrobial resistance. https://bit.ly/3i43wb6

Liquid mycobacterial culture outcomes after different sputum collection techniques before and during treatment

SETTING

Mycobacterial sputum culture is a key diagnostic and research tool.

OBJECTIVE

To compare mycobacterial culture outcomes of three sputum collection methods.

DESIGN

We compared culture results within sets of three sputum samples collected from 18 HIV-infected adult tuberculosis patients at regular intervals up to 84 days after treatment initiation. The first sputum was collected at home and brought to the clinic, where a second and third sputum were consecutively collected under supervision following mouthwash with bottled water and chlorhexidine solution respectively. All sputa were processed for liquid culture in duplicate.

RESULTS

Out of 556 cultures 430 (77.3%), 91 (16.4%) and 35 (6.3%) were positive, negative or contaminated, respectively. The odds of contamination were higher with home collection and with water rinse than with chlorhexidine rinse (OR: 12.5, p < 0.001 and OR: 6.7, p = 0.015). Chlorhexidine rinse increased the odds of a negative culture compared to water rinse (OR: 3.5, p = 0.002). The odds of a positive culture were greater with water rinse than with home collection (OR: 2.5, p = 0.005). Water rinse significantly reduced time to culture positivity.

CONCLUSION

Compared to sputum collected at home, chlorhexidine rinse reduces culture contamination and water rinse increases the rate and viable mycobacterial load of positive cultures.

High-dose rifampicin, moxifloxacin, and SQ109 for treating tuberculosis: a multi-arm, multi-stage randomised controlled trial

BACKGROUND

Tuberculosis is the world's leading infectious disease killer. We aimed to identify shorter, safer drug regimens for the treatment of tuberculosis.

METHODS

We did a randomised controlled, open-label trial with a multi-arm, multi-stage design. The trial was done in seven sites in South Africa and Tanzania, including hospitals, health centres, and clinical trial centres. Patients with newly diagnosed, rifampicin-sensitive, previously untreated pulmonary tuberculosis were randomly assigned in a 1:1:1:1:2 ratio to receive (all orally) either 35 mg/kg rifampicin per day with 15-20 mg/kg ethambutol, 20 mg/kg rifampicin per day with 400 mg moxifloxacin, 20 mg/kg rifampicin per day with 300 mg SQ109, 10 mg/kg rifampicin per day with 300 mg SQ109, or a daily standard control regimen (10 mg/kg rifampicin, 5 mg/kg isoniazid, 25 mg/kg pyrazinamide, and 15-20 mg/kg ethambutol). Experimental treatments were given with oral 5 mg/kg isoniazid and 25 mg/kg pyrazinamide per day for 12 weeks, followed by 14 weeks of 5 mg/kg isoniazid and 10 mg/kg rifampicin per day. Because of the orange discoloration of body fluids with higher doses of rifampicin it was not possible to mask patients and clinicians to treatment allocation. The primary endpoint was time to culture conversion in liquid media within 12 weeks. Patients without evidence of rifampicin resistance on phenotypic test who took at least one dose of study treatment and had one positive culture on liquid or solid media before or within the first 2 weeks of treatment were included in the primary analysis (modified intention to treat). Time-to-event data were analysed using a Cox proportional-hazards regression model and adjusted for minimisation variables. The proportional hazard assumption was tested using Schoelfeld residuals, with threshold p<0·05 for non-proportionality. The trial is registered with ClinicalTrials.gov (NCT01785186).

FINDINGS

Between May 7, 2013, and March 25, 2014, we enrolled and randomly assigned 365 patients to different treatment arms (63 to rifampicin 35 mg/kg, isoniazid, pyrazinamide, and ethambutol; 59 to rifampicin 10 mg/kg, isoniazid, pyrazinamide, SQ109; 57 to rifampicin 20 mg/kg, isoniazid, pyrazinamide, and SQ109; 63 to rifampicin 10 mg/kg, isoniazid, pyrazinamide, and moxifloxacin; and 123 to the control arm). Recruitment was stopped early in the arms containing SQ109 since prespecified efficacy thresholds were not met at the planned interim analysis. Time to stable culture conversion in liquid media was faster in the 35 mg/kg rifampicin group than in the control group (median 48 days vs 62 days, adjusted hazard ratio 1·78; 95% CI 1·22-2·58, p=0·003), but not in other experimental arms. There was no difference in any of the groups in time to culture conversion on solid media. 11 patients had treatment failure or recurrent disease during post-treatment follow-up: one in the 35 mg/kg rifampicin arm and none in the moxifloxacin arm. 45 (12%) of 365 patients reported grade 3-5 adverse events, with similar proportions in each arm.

INTERPRETATION

A dose of 35 mg/kg rifampicin was safe, reduced the time to culture conversion in liquid media, and could be a promising component of future, shorter regimens. Our adaptive trial design was successfully implemented in a multi-centre, high tuberculosis burden setting, and could speed regimen development at reduced cost.

FUNDING

The study was funded by the European and Developing Countries Clinical Trials partnership (EDCTP), the German Ministry for Education and Research (BmBF), and the Medical Research Council UK (MRC).

A dose-ranging trial to optimize the dose of rifampin in the treatment of tuberculosis

RATIONALE

Rifampin at a dose of 10 mg/kg was introduced in 1971 based on pharmacokinetic, toxicity, and cost considerations. Available data in mice and humans showed that an increase in dose may shorten the duration of tuberculosis treatment.

OBJECTIVES

To evaluate the safety and tolerability, the pharmacokinetics, and the extended early bactericidal activity of increasing doses of rifampin.

METHODS

Patients with drug-susceptible tuberculosis were enrolled into a control group of eight patients receiving the standard dose of 10 mg/kg rifampin, followed by consecutive experimental groups with 15 patients each receiving rifampin 20, 25, 30, and 35 mg/kg, respectively, for 14 days. In all patients isoniazid, pyrazinamide, and ethambutol were added in standard doses for the second 7 days of treatment. Safety, pharmacokinetics of rifampin, and fall in bacterial load were assessed.

MEASUREMENTS AND MAIN RESULTS

Grade 1 and 2 adverse events were equally distributed between the five dose groups; there were five grade 3 events of which one was a possibly related hepatotoxicity. Areas under the time-concentration curves and peak serum concentrations of rifampin showed a more than proportional increase with dose. The daily fall in bacterial load over 14 days was 0.176, 0.168, 0.167, 0.265, and 0.261 log10 colony-forming units/ml sputum in the 10, 20, 25, 30, and 35 mg/kg groups, respectively.

CONCLUSIONS

Two weeks of rifampin up to 35 mg/kg was safe and well tolerated. There was a nonlinear increase in exposure to rifampin without an apparent ceiling effect and a greater estimated fall in bacterial load in the higher dosing groups. Clinical trial registered with www.clinicaltrials.gov (NCT 01392911).

Efficiency and safety of the combination of moxifloxacin, pretomanid (PA-824), and pyrazinamide during the first 8 weeks of antituberculosis treatment: a phase 2b, open-label, partly randomised trial in patients with drug-susceptible or drug-resistant pulmonary tuberculosis

BACKGROUND

New antituberculosis regimens are urgently needed to shorten tuberculosis treatment. Following on from favourable assessment in a 2 week study, we investigated a novel regimen for efficacy and safety in drug-susceptible and multidrug-resistant (MDR) tuberculosis during the first 8 weeks of treatment.

METHODS

We did this phase 2b study of bactericidal activity--defined as the decrease in colony forming units (CFUs) of Mycobacterium tuberculosis in the sputum of patients with microscopy smear-positive pulmonary tuberculosis-at eight sites in South Africa and Tanzania. We enrolled treatment-naive patients with drug-susceptible, pulmonary tuberculosis, who were randomly assigned by computer-generated sequences to receive either 8 weeks of moxifloxacin, 100 mg pretomanid (formerly known as PA-824), and pyrazinamide (MPa100Z regimen); moxifloxacin, 200 mg pretomanid, and pyrazinamide (MPa200Z regimen); or the current standard care for drug-susceptible pulmonary tuberculosis, isoniazid, rifampicin, PZA, and ethambutol (HRZE regimen). A group of patients with MDR tuberculosis received MPa200Z (DRMPa200Z group). The primary outcome was bactericidal activity measured by the mean daily rate of reduction in M tuberculosis CFUs per mL overnight sputum collected once a week, with joint Bayesian non-linear mixed-effects regression modelling. We also assessed safety and tolerability by monitoring adverse events. This study is registered with ClinicalTrials.gov, number NCT01498419.

FINDINGS

Between March 24, 2012, and July 26, 2013 we enrolled 207 patients and randomly assigned them to treatment groups; we assigned 60 patients to the MPa100Z regimen, 62 to the MPa200Z regimen, and 59 to the HRZE regimen. We non-randomly assigned 26 patients with drug-resistant tuberculosis to the DRMPa200Z regimen. In patients with drug-susceptible tuberculosis, the bactericidal activity of MPa200Z (n=54) on days 0-56 (0·155, 95% Bayesian credibility interval 0·133-0·178) was significantly greater than for HRZE (n=54, 0·112, 0·093-0·131). DRMPa200Z (n=9) had bactericidal activity of 0·117 (0·070-0·174). The bactericidal activity on days 7-14 was strongly associated with bactericidal activity on days 7-56. Frequencies of adverse events were similar to standard treatment in all groups. The most common adverse event was hyperuricaemia in 59 (29%) patients (17 [28%] patients in MPa100Z group, 17 [27%] patients in MPa200Z group, 17 [29%] patients. in HRZE group, and 8 [31%] patients in DRMPa200Z group). Other common adverse events were nausea in (14 [23%] patients in MPa100Z group, 8 [13%] patients in MPa200Z group, 7 [12%] patients in HRZE group, and 8 [31%] patients in DRMPa200Z group) and vomiting (7 [12%] patients in MPa100Z group, 7 [11%] patients in MPa200Z group, 7 [12%] patients in HRZE group, and 4 [15%] patients in DRMPa200Z group). No on-treatment electrocardiogram occurrences of corrected QT interval more than 500 ms (an indicator of potential of ventricular tachyarrhythmia) were reported. No phenotypic resistance developed to any of the drugs in the regimen.

INTERPRETATION

The combination of moxifloxacin, pretomanid, and pyrazinamide, was safe, well tolerated, and showed superior bactericidal activity in drug-susceptible tuberculosis during 8 weeks of treatment. Results were consistent between drug-susceptible and MDR tuberculosis. This new regimen is ready to enter phase 3 trials in patients with drug-susceptible tuberculosis and MDR-tuberculosis, with the goal of shortening and simplifying treatment.

FUNDING

Global Alliance for TB Drug Development.

Early phase evaluation of SQ109 alone and in combination with rifampicin in pulmonary TB patients

OBJECTIVES

SQ109, an asymmetrical diamine, is a novel anti-TB drug candidate. This first study in patients was done to determine safety, tolerability, pharmacokinetics and bacteriological effect of different doses of SQ109 alone and in combination with rifampicin when administered over 14 days.

PATIENTS AND METHODS

Smear-positive pulmonary TB patients were randomized into six groups of 15 to receive once-daily oral treatment with 75, 150 or 300 mg of SQ109, rifampicin (10 mg/kg body weight), rifampicin plus 150 mg of SQ109, or rifampicin plus 300 mg of SQ109 for 14 days. Patients were hospitalized for supervised treatment, regular clinical, biochemical and electrocardiographic safety assessments, pharmacokinetic profiling and daily overnight sputum collection.

RESULTS

SQ109 was safe and generally well tolerated. Mild to moderate dose-dependent gastrointestinal complaints were the most frequent adverse events. No relevant QT prolongation was noted. Maximum SQ109 plasma concentrations were lower than MICs. Exposure to SQ109 (AUC0-24) increased by drug accumulation upon repeated administration in the SQ109 monotherapy groups. Co-administration of SQ109 150 mg with rifampicin resulted in decreasing SQ109 exposures from day 1 to day 14. A higher (300 mg) dose of SQ109 largely outweighed the evolving inductive effect of rifampicin. The daily fall in log cfu/mL of sputum (95% CI) was 0.093 (0.126-0.059) with rifampicin, 0.133 (0.166-0.100) with rifampicin plus 150 mg of SQ109 and 0.089 (0.121-0.057) with rifampicin plus 300 mg of SQ109. Treatments with SQ109 alone showed no significant activity.

CONCLUSIONS

SQ109 alone or with rifampicin was safe over 14 days. Upon co-administration with rifampicin, 300 mg of SQ109 yielded a higher exposure than the 150 mg dose. SQ109 did not appear to be active alone or to enhance the activity of rifampicin during the 14 days of treatment.

Pre-treatment mycobacterial sputum load influences individual on-treatment measurements

Time to culture positivity (TTP) in liquid medium is now widely available as a measure of viable mycobacterial sputum load. TTP correlates well with and could replace colony-forming unit (CFU) counting in studies of antituberculosis drug effects. We investigated the influence of the pre-treatment mycobacterial sputum load on 4428 CFU measurements obtained within the first 14 days of treatment. Using a prediction model we show that pre-treatment CFU counts contribute 29% to the variation of on-treatment CFU counts and increase the precision of the prediction of on-treatment CFU from TTP by 12%. On the other hand, pre-treatment TTP contributed only 12% to the variation of on-treatment TTP and only added 2% to the prediction of TTP from CFU. We conclude pre-treatment measurements are covariates that can enhance the accuracy of statistical estimates of treatment effects, particularly when measured by CFU counts.

Mycobactericidal activity of sutezolid (PNU-100480) in sputum (EBA) and blood (WBA) of patients with pulmonary tuberculosis

Rationale

Sutezolid (PNU-100480) is a linezolid analog with superior bactericidal activity against Mycobacterium tuberculosis in the hollow fiber, whole blood and mouse models. Like linezolid, it is unaffected by mutations conferring resistance to standard TB drugs. This study of sutezolid is its first in tuberculosis patients.

Methods

Sputum smear positive tuberculosis patients were randomly assigned to sutezolid 600 mg BID (N = 25) or 1200 mg QD (N = 25), or standard 4-drug therapy (N = 9) for the first 14 days of treatment. Effects on mycobacterial burden in sputum (early bactericidal activity or EBA) were monitored as colony counts on agar and time to positivity in automated liquid culture. Bactericidal activity was also measured in ex vivo whole blood cultures (whole blood bactericidal activity or WBA) inoculated with M. tuberculosis H37Rv.

Results

All patients completed assigned treatments and began subsequent standard TB treatment according to protocol. The 90% confidence intervals (CI) for bactericidal activity in sputum over the 14 day interval excluded zero for all treatments and both monitoring methods, as did those for cumulative WBA. There were no treatment-related serious adverse events, premature discontinuations, or dose reductions due to laboratory abnormalities. There was no effect on the QT interval. Seven sutezolid-treated patients (14%) had transient, asymptomatic ALT elevations to 173±34 U/L on day 14 that subsequently normalized promptly; none met Hy's criteria for serious liver injury.

Conclusions

The mycobactericidal activity of sutezolid 600 mg BID or 1200 mg QD was readily detected in sputum and blood. Both schedules were generally safe and well tolerated. Further studies of sutezolid in tuberculosis treatment are warranted.

Trial Registration

ClinicalTrials.gov NCT01225640

Assessment of the sensitivity and specificity of Xpert MTB/RIF assay as an early sputum biomarker of response to tuberculosis treatment

BACKGROUND

An accurate biomarker is urgently needed to monitor the response to treatment in patients with pulmonary tuberculosis. The Xpert MTB/RIF assay is a commercially available real-time PCR that can be used to detect Mycobacterium-tuberculosis-specific DNA sequences in sputum samples. We therefore evaluated this assay with serial sputum samples obtained over 26 weeks from patients undergoing treatment for tuberculosis.

METHODS

We analysed sputum samples from 221 patients with smear-positive tuberculosis enrolled at two sites (Cape Town, South Africa, and Mbeya, Tanzania) of a multicentre randomised clinical trial REMoxTB of antituberculosis treatment on a weekly basis (weeks 0 to 8), then at weeks 12, 17, 22, and 26 after treatment initiation. The Xpert MTB/RIF results over time were compared with the results of standard smear microscopy and culture methods.

FINDINGS

We obtained and analysed 2741 sputum samples from 221 patients. The reduction in positivity rates with Xpert MTB/RIF were slower than those with the standard methods. At week 8, positive results were obtained for 62 (29%) of 212 sputum samples with smear microscopy, 46 (26%) of 175 with solid culture (Löwenstein-Jensen medium), 77 (42%) of 183 with liquid culture (Bactec MGIT960 system), and 174 (84%) of 207 with Xpert MTB/RIF; at 26 weeks, positive results were obtained for ten (5%) of 199, four (3%) of 157, seven (4%) of 169, and 22 (27%) of 83 sputum samples, respectively. The reduction in detection of quantitative M tuberculosis DNA with Xpert MTB/RIF correlated with smear grades (ρ=-0·74; p<0·0001), solid culture grades (ρ=-0·73; p<0·0001), and time to liquid culture positivity (ρ=0·73; p<0·0001). Compared with the combined binary smear and culture results as a reference standard, the Xpert MTB/RIF assay had high sensitivity (97·0%, 95% CI 95·8-97·9), but poor specificity (48·6%, 45·0-52·2).

INTERPRETATION

The poor specificity precludes the use of the Xpert MTB/RIF assay as a biomarker for monitoring tuberculosis treatment, and should not replace standard smear microscopy and culture.

FUNDING

Global Alliance for TB Drug Development, Bill & Melinda Gates Foundation, UK Medical Research Council, German Ministry of Science and Technology.

14-day bactericidal activity of PA-824, bedaquiline, pyrazinamide, and moxifloxacin combinations: a randomised trial

BACKGROUND

New drugs, but also shorter, better-tolerated regimens are needed to tackle the high global burden of tuberculosis complicated by drug resistance and retroviral disease. We investigated new multiple-agent combinations over the first 14 days of treatment to assess their suitability for future development.

METHODS

In this prospective, randomised, early bactericidal activity (EBA) study, treatment-naive, drug-susceptible patients with uncomplicated pulmonary tuberculosis were admitted to hospitals in Cape Town, South Africa, between Oct 7, 2010, and Aug 19, 2011. Patients were randomised centrally by computer-generated randomisation sequence to receive bedaquiline, bedaquiline-pyrazinamide, PA-824-pyrazinamide, bedaquiline-PA-824, PA-824-moxifloxacin-pyrazinamide, or unmasked standard antituberculosis treatment as positive control. The primary outcome was the 14-day EBA assessed in a central laboratory from the daily fall in colony forming units (CFU) of M tuberculosis per mL of sputum in daily overnight sputum collections. Bilinear regression curves were fitted for each group separately and groups compared with ANOVA for ranks, followed by pair-wise comparisons adjusted for multiplicity. Clinical staff were partially masked but laboratory personnel were fully masked. This study is registered, NCT01215851.

FINDINGS

The mean 14-day EBA of PA-824-moxifloxacin-pyrazinamide (n=13; 0·233 [SD 0·128]) was significantly higher than that of bedaquiline (14; 0·061 [0·068]), bedaquiline-pyrazinamide (15; 0·131 [0·102]), bedaquiline-PA-824 (14; 0·114 [0·050]), but not PA-824-pyrazinamide (14; 0·154 [0·040]), and comparable with that of standard treatment (ten; 0·140 [0·094]). Treatments were well tolerated and appeared safe. One patient on PA-824-moxifloxacin-pyrazinamide was withdrawn because of corrected QT interval changes exceeding criteria prespecified in the protocol.

INTERPRETATION

PA-824-moxifloxacin-pyrazinamide is potentially suitable for treating drug-sensitive and multidrug-resistant tuberculosis. Multiagent EBA studies can contribute to reducing the time needed to develop new antituberculosis regimens.

FUNDING

The Global Alliance for TB Drug Development (TB Alliance).

Early bactericidal activity of delamanid (OPC-67683) in smear-positive pulmonary tuberculosis patients

BACKGROUND

Delamanid (OPC-67683) is a novel mycolic acid biosynthesis inhibitor active against Mycobacterium tuberculosis at a low minimum inhibitory concentration.

METHODS

Forty-eight patients with smear-positive tuberculosis (63% male; 54.7 ± 9.9 kg; 30.7 ± 10.8 years) were randomly assigned to receive delamanid 100, 200, 300 or 400 mg daily for 14 days. Colony forming units (cfu) of M. tuberculosis were counted on agar plates from overnight sputum collections to calculate early bactericidal activity (EBA), defined as fall in log(10) cfu/ml sputum/day.

RESULTS

The EBA of delamanid was monophasic and not significantly different between dosages; however, more patients receiving 200 mg (70%) and 300 mg (80%) experienced a response of ≥0.9 log(10) cfu/ml sputum decline over 14 days than those receiving 100 mg (45%) and 400 mg (27%). The average EBA of all dosages combined (0.040 ± 0.056 log(10) cfu/ml sputum/day) was significant from day 2 onward. Delamanid exposure was less than dosage-proportional, reaching a plateau at 300 mg, likely due to dose-limited absorption. Moderate but significant correlation was found between C(max) and EBA, indicating exposure dependence. Delamanid was well tolerated without significant toxicity.

CONCLUSIONS

Delamanid at all dosages was safe, well tolerated and demonstrated significant exposure-dependent EBA over 14 days, supporting further investigation of its pharmacokinetics and anti-tuberculosis activity.

Guideline for the management of chronic obstructive pulmonary disease--2011 update

OBJECTIVE

To revise the South African Guideline for the Management of Chronic Obstructive Pulmonary Disease (COPD) based on emerging research that has informed updated recommendations.

KEY POINTS

(1) Smoking is the major cause of COPD, but exposure to biomass fuels and tuberculosis are important additional factors. (2) Spirometry is essential for the diagnosis and staging of COPD. (3) COPD is either undiagnosed or diagnosed too late, so limiting the benefit of therapeutic interventions; performing spirometry in at-risk individuals will help to establish an early diagnosis. (4) Oral corticosteroids are no longer recommended for maintenance treatment of COPD. (5) A therapeutic trial of oral corticosteroids to distinguish corticosteroid responders from non-responders is no longer recommended. (6) Primary and secondary prevention are the most cost-effective strategies in COPD. Smoking cessation as well as avoidance of other forms of pollution can prevent disease in susceptible individuals and ameliorate progression. Bronchodilators are the mainstay of pharmacotherapy, relieving dyspnoea and improving quality of life. (7) Inhaled corticosteroids are recommended in patients with frequent exacerbations and have a synergistic effect with bronchodilators in improving lung function, quality of life and exacerbation frequency. (8) Acute exacerbations of COPD significantly affect morbidity, health care units and mortality. (9) Antibiotics are only indicated for purulent exacerbations of chronic bronchitis. (10) COPD patients should be encouraged to engage in an active lifestyle and participate in rehabilitation programmes.

OPTIONS

Treatment recommendations are based on the following: annual updates of the Global Obstructive Lung Disease (GOLD), initiative, that provide an evidence-based comprehensive review of management; independent evaluation of the level of evidence in support of some of the new treatment trends; and consideration of factors that influence COPD management in South Africa, including lung co-morbidity and drug availability and cost.

OUTCOME

Holistic management utilising pharmacological and nonpharmacological options are put in perspective.

EVIDENCE

Working groups of clinicians and clinical researchers following detailed literature review, particularly of studies performed in South Africa, and the GOLD guidelines. BENEFITS, HARMS AND COSTS. The guideline pays particular attention to cost-effectiveness in South Africa, and promotes the initial use of less costly options. It promotes smoking cessation and selection of treatment based on objective evidence of benefit. It also rejects a nihilistic or punitive approach, even in those who are unable to break the smoking addiction.

RECOMMENDATIONS

These include primary and secondary prevention; early diagnosis, staging of severity, use of bronchodilators and other forms of treatment, rehabilitation, and treatment of complications. Advice is provided on the management of acute exacerbations and the approach to air travel, prescribing long-term oxygen and lung surgery including lung volume reduction surgery.

VALIDATION

The COPD Working Group comprised experienced pulmonologists representing all university departments in South Africa and some from private practice, and general practitioners. Most contributed to the development of the previous version of the South African guideline. GUIDELINE SPONSOR: The meeting of the Working Group of the South African Thoracic Society was sponsored by an unrestricted educational grant from Boehringer Ingelheim and Glaxo-Smith-Kline.

Time to detection of the growth of Mycobacterium tuberculosis in MGIT 960 for determining the early bactericidal activity of antituberculosis agents

Evaluation of early bactericidal activity (EBA) by the determination of a fall in viable colony-forming units (CFU) of Mycobacterium tuberculosis in sputum is a first step in the clinical study of new antituberculosis agents. The time to detection (TTD) of growth in liquid media is more sensitive and could substitute for CFU counting on solid media. Overnight sputum samples collected during the evaluation of the novel agent TMC207 in comparison to isoniazid and rifampicin were studied. For the determination of CFU, we incubated 10-fold dilutions of homogenized sputum on selective 7H10 agar. The TTD was measured by incubating decontaminated sputum in the BACTEC MGIT 960 system. The fall in bacillary load over 7 days determined by CFU counting closely matched the prolongation of the TTD in the BACTEC MGIT 960 system. The CFU counts correlated significantly with the TTD. While the ranking of agents and different dosages of TMC207 was similar, the highest dose of TMC207 showed markedly better activity when measured by the TTD than CFU counting when compared to the activity of isoniazid. Automated TTD could augment, or, in future, replace, CFU counting to determine sputum bacillary load in EBA clinical trials pending a more formal evaluation of the correlation of the measurements.

Ethionamide cross- and co-resistance in children with isoniazid-resistant tuberculosis

BACKGROUND

Ethionamide (ETH) is a structural analogue of isoniazid (INH). Both are pro-drugs requiring activation by separate and common enzyme pathways, which could lead to co- and/or cross-resistance.

OBJECTIVE

To characterise paediatric INH-resistant mycobacterial isolates to investigate the presence of ETH resistance and mutations in the katG gene and the inhA promoter region.

METHODS

Forty-five INH-resistant and 19 INH-susceptible Mycobacterium tuberculosis control isolates from children from the Western Cape Province, South Africa, were analysed to quantify INH minimal inhibitory concentration, test for ETH resistance and investigate mutations in the katG gene and/or inhA promoter region.

RESULTS

Among 45 INH-resistant children, ETH resistance was present in 19 of 39 (49%). An inhA promoter mutation was identified in 15 (33.3%); 12/14 (86%) of these isolates were also ETH-resistant. Of the 21 isolates with a katG mutation, six (29%) were ETH-resistant. No isolate had both katG and inhA promoter mutations. Nine (20%) isolates had neither inhA promoter nor katG mutations. Of 15 isolates with inhA promoter mutation, 14 (93%) displayed low- or intermediate-level INH resistance. Among the 19 INH-susceptible isolates, ETH resistance was present in 1/18 (6%) and none showed inhA or katG gene mutations.

CONCLUSION

We found a high level of cross- and co-resistance with ETH among INH-resistant M. tuberculosis isolates from children in this geographic area.

The diarylquinoline TMC207 for multidrug-resistant tuberculosis

BACKGROUND

The diarylquinoline TMC207 offers a new mechanism of antituberculosis action by inhibiting mycobacterial ATP synthase. TMC207 potently inhibits drug-sensitive and drug-resistant Mycobacterium tuberculosis in vitro and shows bactericidal activity in patients who have drug-susceptible pulmonary tuberculosis.

METHODS

In the first stage of a two-stage, phase 2, randomized, controlled trial, we randomly assigned 47 patients who had newly diagnosed multidrug-resistant pulmonary tuberculosis to receive either TMC207 (400 mg daily for 2 weeks, followed by 200 mg three times a week for 6 weeks) (23 patients) or placebo (24 patients) in combination with a standard five-drug, second-line antituberculosis regimen. The primary efficacy end point was the conversion of sputum cultures, in liquid broth, from positive to negative.

RESULTS

The addition of TMC207 to standard therapy for multidrug-resistant tuberculosis reduced the time to conversion to a negative sputum culture, as compared with placebo (hazard ratio, 11.8; 95% confidence interval, 2.3 to 61.3; P=0.003 by Cox regression analysis) and increased the proportion of patients with conversion of sputum culture (48% vs. 9%). The mean log(10) count of colony-forming units in the sputum declined more rapidly in the TMC207 group than in the placebo group. No significant differences in average plasma TMC207 concentrations were noted between patients with and those without culture conversion. Most adverse events were mild to moderate, and only nausea occurred significantly more frequently among patients in the TMC207 group than among patients in the placebo group (26% vs. 4%, P=0.04).

CONCLUSIONS

The clinical activity of TMC207 validates ATP synthase as a viable target for the treatment of tuberculosis. (ClinicalTrials.gov number, NCT00449644.)

The role of a positive trigger event in actioning authentic leadership development

Authenticity can best be understood in context, and context implies action (Payne, 1996). For the purpose of this study, leadership in general, and authentic leadership in particular, were explored in terms of the actions of former mayor of New York City, Rudolph Giuliani, who displayed authentic leadership in action during the tragic aftermath of the World Trade Centre attacks. Authentic leadership development tends to be triggered by a negative event (as in the case of 9/11 for Giuliani, for example). Since there is limited knowledge of how a positive event may trigger authentic leadership development, the aim of this study was to explore the potential of Appreciative Inquiry (AI) - an affirmative mode of action research - as a positive trigger event for authentic leadership development. The results indicated that this positive approach to change could indeed be implemented for this purpose.

Early bactericidal activity of high-dose rifampin in patients with pulmonary tuberculosis evidenced by positive sputum smears

We studied the early bactericidal activity of twice the standard dose of rifampin in subjects with pulmonary tuberculosis evidenced by positive smears. The observed mean 2-day activity was almost double that reported at the standard dose. Further studies are warranted to establish whether higher rifampin doses might assist in shortening tuberculosis treatment.

The influence of dose and N-acetyltransferase-2 (NAT2) genotype and phenotype on the pharmacokinetics and pharmacodynamics of isoniazid

OBJECTIVE

This study evaluated the pharmacokinetics of isoniazid (INH) associated with optimal early bactericidal activity (EBA), defined as 90% of the maximum EBA (EBA(90)) and the influence of N-acetyltransferase-2 (NAT2) subtype on the ability of pulmonary tuberculosis (PTB) patients to reach the identified pharmacokinetic values after INH doses ranging from 0.2 to 10-12 mg/kg body weight.

METHODS

INH serum concentrations and NAT2 subtype were determined during four studies of PTB patients in three of whom the EBA of INH was determined. The relationship of EBA to area under the curve (AUC) (AUC(0-infinity)) and 2-h serum concentrations was examined by exponential regression and fitted curves estimated the AUC(0-infinity) and 2-h serum concentrations at which EBA(90) was reached.

RESULTS

EBA(90) was reached at an AUC(0-infinity) of 10.52 microg/ml per hour and 2-h serum concentrations of 2.19 microg/ml. An AUC(0-infinity) of 10.52 microg/ml per hour was reached by all 66 patients receiving a 10-12 mg/kg INH dose and all 21 receiving 6 mg/kg, except 1 of 10 (10%) homozygous fast (FF) acetylators; however, at 5 mg/kg, 4 of 12 (33%) FF and 26 of 27 (96%) heterozygous fast (FS), but all 21 homozygous slow (SS) acetylators did so; and 1 of 3 (33%) FF, 2 of 6 (33%) FS, but all 4 SS acetylators at dose 3 mg/kg. An INH 2-h serum concentration of 2.19 microg/ml was reached by all 66 patients receiving 10-12 mg/kg and all 21 receiving 6 mg/kg, except for 2 (20%) FF acetylators at a dose of 5 mg/kg; however, only 3 (25%) of 12 FF acetylators, but 26 (96%) of 27 FS acetylators, and all 21 SS acetylators reached this concentration; and at a dose of 3 mg/kg, 1 (33%) of 3 FF acetylators, 2 (33%) of 6 FF, but all 4 SS acetylators.

CONCLUSIONS

At a 6 mg/kg dose, all except a minority of FF NAT2 acetylators, achieve an INH AUC(0-infinity) and 2-h INH serum concentrations associated with EBA(90), as did all 4 SS acetylators receiving 3 mg/kg. Any dose reduction below 6 mg/kg body weight will tend to disadvantage a significant proportion of faster acetylators, but, conversely, SS acetylators require only a 3 mg/kg dose to achieve a satisfactory exposure to INH.

Radionuclides in fruit systems: model prediction-experimental data intercomparison study

This paper presents results from an international exercise undertaken to test model predictions against an independent data set for the transfer of radioactivity to fruit. Six models with various structures and complexity participated in this exercise. Predictions from these models were compared against independent experimental measurements on the transfer of 134Cs and 85Sr via leaf-to-fruit and soil-to-fruit in strawberry plants after an acute release. Foliar contamination was carried out through wet deposition on the plant at two different growing stages, anthesis and ripening, while soil contamination was effected at anthesis only. In the case of foliar contamination, predicted values are within the same order of magnitude as the measured values for both radionuclides, while in the case of soil contamination models tend to under-predict by up to three orders of magnitude for 134Cs, while differences for 85Sr are lower. Performance of models against experimental data is discussed together with the lessons learned from this exercise.

Radionuclides in fruit systems: model-model intercomparison study

Modeling is widely used to predict radionuclide distribution following accidental radionuclide releases. Modeling is crucial in emergency response planning and risk communication, and understanding model uncertainty is important not only in conducting analysis consistent with current regulatory guidance, but also in gaining stakeholder and decision-maker trust in the process and confidence in the results. However, while methods for dealing with parameter uncertainty are fairly well developed, an adequate representation of uncertainties associated with models remains rare. This paper addresses uncertainty about a model's structure (i.e., the relevance of simplifying assumptions and mathematical equations) that is seldom addressed in practical applications of environmental modeling. The use of several alternative models to derive a range of model outputs or risks is probably the only available technique to assess consistency in model prediction. Since each independent model requires significant resources for development and calibration, multiple models are not generally applied to the same problem. This study uses results from one such model intercomparison conducted by the Fruits Working Group, which was created under the International Atomic Energy Agency (IAEA) BIOMASS (BIOsphere Modelling and ASSessment) Program. Model-model intercomparisons presented in this study were conducted by the working group for two different scenarios (acute or continuous deposition), one radionuclide ((137)Cs), and three fruit-bearing crops (strawberries, apples, and blackcurrants). The differences between models were as great as five orders of magnitude for short-term predictions following acute radionuclide deposition. For long-term predictions and for the continuous deposition scenario, the differences between models were about two orders of magnitude. The difference between strawberry, apple, and blackcurrant contamination predicted by one model is far less than the difference in prediction of contamination for a single plant species given by different models. This study illustrates the importance of problem formulation and implementation of an analytic-deliberative process in risk characterization.

Monitoring the ingestion of anti-tuberculosis drugs by simple non-invasive methods

This investigation retrospectively assessed inexpensive non-invasive qualitative methods to monitor the ingestion of anti-tuberculosis drugs isoniazid, rifampicin and rifapentine. Results showed that commercial test strips detected the isoniazid metabolites isonicotinic acid and isonicotinylglycine as efficiently as the isonicotinic acid method in 150 urine samples. The presence of rifamycins in urine samples (n=1085) was detected by microbiological assay techniques and the sensitivity compared to the n-butanol extraction colour test in 91 of these specimens. The proportions detected by the two methods were significantly different and the sensitivity of the n-butanol procedure was only 63.8% (95% CL 51.2-76.4%) as compared to that of the superior microbiological method. Final validation (n=691) showed that qualitative assays measure isoniazid and rifamycin ingestion with an efficiency similar to high-performance liquid chromatography. The qualitative procedures may therefore be valuable in clinical trials and in tuberculosis clinics to confirm drug ingestion.

Rethinking undergraduate curricula: A Delphi study of human resource management and industrial and organisational psychology

The aim of this qualitative study is to bring clarity to the confusion about the interconnectedness, similarities and differences between the fields of Human Resource Management (HRM) and Industrial and Organisational Psychology (I&OP), for the purposes of curriculum development. The Delphi technique was used to gather data from 13 participants (five international and eight national). Analysis was done interpretively using Atlas.ti. Results indicate that HRM and I&OP are distinct but interrelated fields of study and can therefore be presented in separate but interrelated undergraduate curricula. Opsomming Die doel van die kwalitatiewestudie is om duidelikheid te verkry oor die verwarring rakende die interverwantskap, ooreenkomste en verskille tussen die velde van Menslike Hulpbronbestuur (MHB) en Bedryfs- en Organisasie Sielkunde vir die doeleindes van kurrikulumontwikkeling. Die Delphi tegniek is gebruik om data van 13 deelnemers (vyf internasionaal en agt nasionaal) te versamel. Ontleding is op ’n interpreterende wyse gedoen deur gebruik te maak van Atlas.ti. Die resultate toon dat MHB en Bedryfs- en Organisasie Sielkunde onderskeibare, maar verbandhoudende studievelde is en daarom aangebied kan word in afsonderlike, maar interverwante voorgraadse kurrikula.

The effect of confidence and method of questioning on eyewitness testimony

Very often eyewitnesses are perceived as being accurate due to the confidence in the accuracy of their own testimony. The confidence displayed by an eyewitness may possibly be increased by the method of questioning used by legal professionals and police. The present study examines the confidence-accuracy relationship and the effect the method of questioning (open-ended versus closed-ended questions) may have on the confidence of eyewitnesses. The sample of 412 respondents consisted of scholars (11 to 14-year-olds), university students, the public and Police College students. A significant relationship between memory accuracy and confidence was found for more than 70% of the questions. Closed-ended questions provided a significantly higher rate of accuracy than open-ended questions. A significantly larger proportion of respondents to the closed-ended questions were more confident about their answers than those who responded to the open-ended questions.

Method of questioning and the accuracy of eyewitness testimony

System variables are integrally part of factors that can be controlled by the legal system to enhance the accuracy of testimony by eyewitnesses. Apart from examining the relationship between questioning as system variable and the accuracy of testimony, the present study furthermore explores the relationship between type of questioning and certain biographical variables (occupation, age, gender and race). To achieve the aim of the study, 412 respondents consisting of 11 to 14-year-olds, university students, the public and Police College students participated and were exposed to open-ended or closed-ended questions. It was found that the participants who responded to the closed-ended questions were significantly more accurate than those who answered the open-ended questions. All the biographical groups, except the public, were more accurate in responding to the closed-ended questions. The scholars obtained the lowest scores (although not always significant) for both the open-ended and closed-ended questions. With respect to age the 18 to 25-year-olds obtained significantly higher scores than the other groups for the closed-ended questions. Whites performed significantly better than blacks in response to the open-ended and closed-ended questions.

Modelling and experimental studies on the transfer of radionuclides to fruit

Although fruit is an important component of the diet, the extent to which it contributes to radiological exposure remains unclear, partially as a consequence of uncertainties in models and data used to assess transfer of radionuclides in the food chain. A Fruits Working Group operated as part of the IAEA BIOMASS (BIOsphere Modelling and ASSessment) programme from 1997 to 2000, with the aim of improving the robustness of the models that are used for radiological assessment. The Group completed a number of modelling and experimental activities including: (i) a review of experimental, field and modelling information on the transfer of radionuclides to fruit; (ii) discussion of recently completed or ongoing experimental studies; (iii) development of a database on the transfer of radionuclides to fruit; (iv) development of a conceptual model for fruit and (v) two model intercomparison studies and a model validation study. The Group achieved significant advances in understanding the processes involved in transfer of radionuclides to fruit. The work demonstrated that further experimental and modelling studies are required to ensure that the current generation of models can be applied to a wide range of scenarios.

Radionuclide migration in forest ecosystems--results of a model validation study

The primary objective of the IAEA's BIOMASS Forest Working Group (FWG) was to bring together experimental radioecologists and modellers to facilitate the exchange of information which could be used to improve our ability to understand and forecast radionuclide transfers within forests. This paper describes a blind model validation exercise which was conducted by the FWG to test nine models which members of the group had developed in response to the need to predict the fate of radiocaesium in forests in Europe after the Chernobyl accident. The outcomes and conclusions of this exercise are summarised. It was concluded that, as a group, the models are capable of providing an envelope of predictions which can be expected to enclose experimental data for radiocaesium contamination in forests over the time scale tested. However, the models are subject to varying degrees of conceptual uncertainty which gives rise to a very high degree of divergence between individual model predictions, particularly when forecasting edible mushroom contamination. Furthermore, the forecasting capability of the models over future decades currently remains untested.

The Influence of Human N-Acetyltransferase Genotype on the Early Bactericidal Activity of Isoniazid

The elimination of isoniazid is subject to the influence of the N-acetyltransferase 2 (NAT2) genotype, and individuals may be homozygotic slow, heterozygotic fast, or homozygotic fast acetylators of isoniazid. The early bactericidal activity (EBA) of an antituberculosis agent can be determined by quantitative culture of Mycobacterium tuberculosis in sputum samples obtained from patients with pulmonary tuberculosis during the first days of treatment. In these studies, the EBA of isoniazid during the first 2 days of treatment was determined for 97 patients with sputum smear-positive pulmonary tuberculosis following isoniazid doses of < or =37.5 mg, 75 mg, 150 mg, 300 mg, and 600 mg. The NAT2 genotype was determined in 70 patients, and the association between EBA and genotype was examined in this subgroup. Similarly, the relationship between EBA and isoniazid serum concentration was evaluated in 87 patients. The mean EBA of isoniazid increased with dose, but it levelled off between doses of 150 mg (mean EBA, 0.572) and 300 mg (mean EBA, 0.553). Significant differences were found in the mean EBA of isoniazid between the homozygous slow acetylator group and the heterozygous fast acetylator group and between the homozygous slow acetylator group and the homozygous fast acetylator group, but not between the heterozygous fast acetylator group and the homozygous fast acetylator group. The EBA appeared to reach a maximum at a 2-h isoniazid concentration of 2-3 microg/mL. These data confirm a significant effect of NAT2 genotype on the EBA of isoniazid over a range of doses.

Critical Competencies To Promote A Customer Service Core Capability In A Human Resources Call Centre

In today’s information-intensive environment customer service is an important aspect that differentiates one organisation from another. This research focuses on those individual competencies which will lead to a customer service core capability in a Human Resources Call Centre. Data was obtained from Call Centre agents (n=18), supervisors (n=3) and customers (n=25) by means of five focus group-, three individual- and 25 telephonic interviews, respectively. The transcendental realism research procedure was applied within a qualitative research paradigm. Ten key competencies were identified by all groups of participants. Opsomming In vandag se inligtings-intensiewe omgewing is kliëntediens ’n belangrike aspek wat organisasies van mekaar onderskei. Hierdie navorsing fokus op welke individuele bevoegdhede tot ’n kliëntedienssleutelbekwaamheid in ’n Menslikehulpbron-oproepsentrum sal lei. Data is van Oproepsentrumagente (n=18), -toesighouers (n=3) en -kliënte (n=25) ingewin deur middel van onderskeidelik vyf fokusgroep-, drie individuele- en 25 telefoniese onderhoude. Die transendentale realisme navorsingsprosedure is binne ’n kwalitatiewe navorsingsparadigma toegepas. Tien sleutelbevoegdhede is deur al drie groepe deelnemers geïdentifiseer.

Early bactericidal activity of antituberculosis agents

The early bactericidal activity (EBA) of an antituberculosis agent is arbitrarily defined as the fall in log(10) colony forming units (cfu) of Mycobacterium tuberculosis per ml sputum per day during the first 2 days of treatment. Determining the EBA is an important preliminary step in the clinical evaluation of an antituberculosis agent. We review the results of eight published studies of the EBA of different antituberculosis agents, the impact of these results on our understanding of the actions of the respective agents, the clinical characteristics and sputum findings of patients included in these studies, and explore sources of variation in the EBA results. Patients in these studies had a mean age of 31-36 years, a mean weight of 50-57 kg, 67% were male and 56% had lung involvement covering an area of more than one lung, and 90% had multicavitary disease. None of these findings were related to EBA in any study. The mean log(10) cfu per ml sputum in the first specimen was 6.474. This was related to radiological extent of disease and cavity size in one study (p < 0.001) and, in the case of isoniazid to EBA with a rise in EBA of 0.094 (95% CL 0.029-0.158) for each tenfold rise in cfu counts/ml sputum. The overall variation in EBA in these studies was 0.0303, that due to laboratory processing of specimens was 0.0011, and due to patient characteristics and sputum sampling 0.0212. The EBA is a reproducible investigation that has contributed significantly to our knowledge of the actions and characteristics of both established and new antituberculosis agents. The greatest source of variation in EBA results appears to be that due to interpatient variation in disease characteristics and sputum sampling.

The effect of violent versus non-violent incidents on eyewitness memory

As South Africans are daily subjected to violent incidents for which they are summoned to testify about in court, months or years after the event in question occurred, it is of importance to determine the effect violence has on memory after an extended period of time. The present study not only aimed to determine the accuracy of short-term and long-term memory after exposure to a violent and non-violent incident, but also the relationship between short-term and long-term memory and different biographical variables (occupation, age, gender and race). Four-hundred-and-seventy-four respondents consisting of university students, the business sector and Police College students participated and were divided into a short-term and long-term memory group. After a five to six week retention period a significant decrease in the accuracy scores for both the violent and non-violent incident occurred. Significant higher average scores for all the biographical groups in the short-term memory group in comparisons with the long-term memory groups were obtained.

The relationship between memory and the recall of specific details

When eyewitnesses are exposed to an event, certain details tend to capture their attention more than other details, which ensures the better recall of the details that were observed. As little research has focussed on the relationship between certain biographical variables (occupation, age, gender, race and retention period) and specific event details, the present study attempts to shed some light on this area. A sample of 295 participants was obtained from 12- to 14-year-olds, university students, the public and Police College students that were divided into a short-term and long-term memory group. The details that were focussed on in the questionnaire were divided into obvious physiognomic, less pronounced physiognomic, clothing, circumstantial, and action-related details. Between the short-term and long-term memory groups it was found that significant differences were indicated for only certain items related to obvious physiognomic details, clothing details, circumstantial evidence and action-related details. For all the different biographical groups significant differences were found for certain items belonging to the different groups of details.

Memory accuracy of a real-life simulated incident

Due to an awareness that both laboratory and real-life research present limitations, the present study attempts to combine the two research approaches, making use of the strengths of both methodologies. A real-life situation was created in a classroom and combined with laboratory conditions to determine the influence of certain variables (occupation, age, gender, race and retention interval) on the accuracy of eyewitness reporting. A total of 295 participants consisting of 12- to 14-year-olds, University students, the public and Police College students were divided into a short- and long-term memory group. The short-term group were assessed immediately after witnessing the incident, while the long-term group were only assessed five to six weeks later. It was found that the effect of passage of time was insubstantial; however, the performance of the short-term group had already been disconcertingly poor. The school children did not perform significantly less well than other occupational groups, and the members of the Police did not perform significantly better than the other groups. No significant differences were found for the different gender and racial groups.

A randomized controlled study of the impact of dietary zinc supplementation in the management of children with protein-energy malnutrition in Lesotho. II: Special investigations

Protein-energy malnutrition (PEM) remains one of the common causes of morbidity and mortality among children throughout the world. The supplementation of 10 mg elemental zinc, as zinc sulphate, was evaluated in the management of PEM in a randomized, controlled, double-blind clinical trial in 300 children, aged 6-60 months (zinc, n = 150; control, n = 150) admitted to the Queen Elizabeth II Hospital, Maseru, Lesotho. Supplementation and follow-up were done for 3 months post-discharge from the hospital. Both the supplemented and the control groups presented with biochemically determined zinc deficiency on presentation. Despite supplementation the treated group only began to show evidence of biochemical increase in serum zinc at 60 days post-discharge from hospital. This may represent the period of replacement of the total body zinc. Zinc deficiency was more severe in those children in the control group that died after admission to hospital than those that survived, suggesting that low serum levels in children with PEM are associated with a poor prognosis. Zinc did not emerge as a predicator of poor prognosis in the supplemented group as very few children died in this group. The supplemented group also made significant gains as far as albumin levels were concerned, which probably reflects rehabilitation of their malnutrition. The associated improvement in haematological parameters has not been described before and may be secondary to the decreased burden of disease in the supplemented group. These findings suggest that not only were significant benefits of zinc supplementation shown for morbidity in mortality of children in Lesotho with PEM, but these trends were also demonstrated on biochemical profiles.

A randomized controlled study of the impact of dietary zinc supplementation in the management of children with protein-energy malnutrition in Lesotho. I: Mortality and morbidity

Protein-energy malnutrition (PEM) remains one of the common causes of morbidity and mortality among children throughout the world. The supplementation of 10 mg elemental zinc, as zinc sulphate, was evaluated in the management of PEM in a randomized, controlled double-blind clinical trial in 300 children, aged 6-60 months (zinc, n = 150; control, n = 150) admitted to the Queen Elizabeth II Hospital, Maseru, Lesotho. Supplementation and follow-up were done for 3 months post-discharge from the hospital. Mortality during hospitalization was significantly lower in the zinc supplemented group (4.7 per cent), compared with 16.7 per cent in the control group. The prevalence of morbidity was significantly higher in the control group at 1, 2, and 3 month's follow-up. In the zinc supplemented group 58 per cent of the children were above the 80th percentile of expected weight-for-age 3 months after discharge, compared with 27.6 per cent in the control group. Dietary zinc supplementation resulted in a significant reduction in diarrhoeal disease, respiratory morbidity, and episodes of clinical anaemia, skin infections, and fever as well as vomiting in children with PEM. These findings suggest that interventions to improve zinc intake in their management may be of benefit to Basotho children in Lesotho with PEM.

The early bactericidal activity of streptomycin

SETTING

Patients with sputum smear-positive, newly diagnosed pulmonary tuberculosis studied at Tygerburg Hospital, Cape Town, for their early response to streptomycin (SM).

OBJECTIVE

To determine the standard early bactericidal activity (EBA), namely the fall in viable counts of tubercle bacilli in 16-hour sputum collections during the first 2 days of treatment with SM.

DESIGN

Patients were randomised to logarithmically spaced daily doses of 7.5, 15 or 30 mg/kg SM. A comparison by standard biological assay methods was then made with previous estimations of the EBA of paromomycin in doses of 7.5 and 15 mg/kg.

RESULTS

An EBA of 0.133 obtained with 30 mg/kg SM differed significantly from zero (P = 0.0009), while the EBAs of 0.043 with 15 mg/kg and -0.025 with 7.5 mg/kg did not so differ. A linear regression equation of EBA = -0.2587 + 0.2627 log10 dose was obtained with significant slope (P = 0.007). Paromomycin was estimated to be 1.745 more potent than SM with wide 95% confidence limits (0.6-28.6), indicating that it cannot be considered more potent than SM.

CONCLUSIONS

The low EBAs show that SM has low, dose-related, bactericidal activity in cavities, consistent with results from clinical trials. If streptomycin-resistant bacilli are present, paromomycin is probably the aminoglycoside of choice.

Children with intellectual disability in rural South Africa: prevalence and associated disability

The objective of the present study was to determine the prevalence of intellectual disability (ID) and its associated disabilities in rural South African children aged 2-9 years. It was undertaken in eight villages in the district of Bushbuckridge, Northern Province, South Africa. A two-phase design was utilized. The first phase involved screening children on a house-to-house basis by interviewing mothers or caregivers using an internationally validated questionnaire for detecting childhood disability in developing countries. The second phase consisted of a paediatric/neurodevelopmental assessment of the children who screened positive. A total of 6692 children were screened; 722 (10.8%) had a paediatric evaluation and 238 children were diagnosed with ID, giving a minimum observed prevalence of 35.6 per 1000 children in this population. The prevalence of severe and mild ID was 0.64 per 1000 and 29.1 per 1000 children, respectively. The male:female ratio of children with ID was 3:2. In the affected children, a congenital aetiology for the ID was determined in 49 subjects (20.6%), an acquired aetiology in 15 (6.3%) and the aetiology was undetermined in 174 children (73.1%). Epilepsy (15.5%) and cerebral palsy (8.4%) were the commonest associated disabilities. The present study represents the first data on the prevalence of ID and associated disabilities in rural South African children. The prevalence of ID was comparable with results from a study performed in one other African country (Zambia) as well as those from other developing countries. The data provide an initial factual insight into ID and its associated disabilities for healthcare, social service and educational policy planners. This study provides a basis for the initiation and development of appropriate and integrated services for the best possible care of individuals affected with these disabilities, and for their possible prevention.

Early bactericidal activity of amoxicillin in combination with clavulanic acid in patients with sputum smear-positive pulmonary tuberculosis

The early bactericidal activity (EBA) of an antituberculosis agent is the rate of decrease in viable colony-forming units (CFU) per milliliter of sputum during the first 2 d of treatment of patients with previously untreated smear-positive pulmonary tuberculosis. The objective of this open randomized study was to evaluate the EBA of the combination of amoxicillin 3 g and clavulanic acid 750 mg. Ten patients with a mean age of 34 y and a mean weight of 56 kg received amoxicillin/clavulanic acid and 5 patients with a mean age of 34 y and a mean weight of 57 kg received no drug. In the patients receiving 1 dose of amoxicillin/clavulanic acid daily for 2 d the mean log10CFU/ml of sputum before treatment was 6.7402 (SD 0.539) and after 2 d of treatment 6.7046 (SD 0.609); the corresponding values in patients receiving no drug were 6.7823 (SD 0.563) and 6.7502 (SD 0.673), respectively. The EBA of 0.018 (SD 0.130) in patients receiving amoxicillin/clavulanic acid did not differ significantly from that of 0.016 (SD 0.069) in patients receiving no drug. It is unlikely that the combination of amoxicillin/clavulanic acid has an important place in the treatment of tuberculosis with the exception of those patients with multidrug-resistant tuberculosis who are otherwise therapeutically destitute.

The early bactericidal activity of a low-clearance liposomal amikacin in pulmonary tuberculosis

The early bactericidal activity (EBA) of a liposomal preparation of amikacin (MiKasome) with a long plasma half-life of 120-200 h was examined in seven patients with newly diagnosed, smear-positive pulmonary tuberculosis. Liposomal amikacin was given in slow iv infusions of 30 mg total amikacin/kg body weight on three successive days. Cfu counts were set up on 16 h sputum collections preceding the first dose and following each dose and were used for calculating the EBA. Despite the high concentrations of total amikacin, >1000 mg/L, obtainable in plasma, no evidence of EBA was obtained. In view of the considerable activity of liposomal amikacin in experimental murine tuberculosis, this finding indicates that liberation of amikacin from the long-life liposomes occurs only in macrophages that are not usually present in the vicinity of the large extracellular clumps of bacilli in the cavity caseum.