Relapse rates and a 10-year follow-up of a 6-week quadruple drug regimen for multibacillary leprosy.

Between 1989 and 1993, 136 multibacillary leprosy patients received a 6-week treatment regimen consisting of daily rifampicin 600 mg, ofloxacin 400 mg, clofazimine 100 mg and a weekly dose of 100 mg minocycline. A previous analysis after a mean follow-up of 4-7 years revealed a relapse rate of 2%, involving six late (after more than 5 years of follow-up) relapses. During the following years, 12 more relapses appeared during years 8-9 of follow-up. A mean follow-up period of 5 years is insufficient to evaluate treatment regimens in multibacillary leprosy. The present regimen cannot be recommended.

Classification of leprosy cases under field conditions in Bangladesh. I. Usefulness of skin-smear examinations.

In 2 non-governmental organization projects in Bangladesh 244 new leprosy patients were classified in the field according to clinical criteria. Skin smears were taken at 4 standardized sites and at the most active peripheral lesion, where a biopsy was also taken. Comparison of the clinical field classification with the results of the skin smears and biopsies gives a sensitivity of 92.1% for the clinical criteria, but a specificity of only 41.3%. The skin-smear results, on the other hand, have a sensitivity of 88.4% and a specificity of 98.1%. Thus, skin smears may contribute considerably to the operational classification of leprosy patients under field conditions. Quality control of the peripheral laboratory is essential. Appropriate site selection for the smear taking will also contribute to increased performance. Analysis of the skin-smear results suggests that the policy of taking smears at standardized sites should be abandoned in favour of the earlobes and active peripheral lesions.

Classification of leprosy cases under field conditions in Bangladesh. II. Reliability of clinical criteria.

In 2 non-governmental organization projects 244 new leprosy patients in Bangladesh were classified in the field according to clinical criteria i.e. number of skin lesions and number of enlarged nerves. Comparison of these classification results with the results of skin smears and biopsies yielded a sensitivity (for detection of a MB case) of 92.1%, but the 'unconfirmed MB rate' amounted to 52.6%. In order to improve the reliability of the operational classification, several additional clinical criteria were investigated. It was found that neither the presence of anaesthesia in the skin lesions nor the presence of grade 2 disabilities or peripheral anaesthesia or voluntary muscle testing (VMT) impairment contributed to an improved classification. Counting the number of body areas showing signs of leprosy, which had proven very useful in other programmes, did not result in a more reliable classification in the 2 projects in Bangladesh. The presence of clinical signs of lepromatous leprosy, more specifically nodules or diffuse infiltration, could be a useful addition to the classification criteria. If the sensitivity must remain higher than 90%, the lowest 'unconfirmed MB rate' obtainable in Bangladesh, using clinical criteria only, is 46.4%, for a sensitivity of 91.0%. However, the inclusion of skin-smear results in the classification criteria could improve the sensitivity to 96.6% and lower the 'unconfirmed MB rate' to 40.3%. A reduction in MB overclassification will result in more efficient and more cost-effective leprosy control programmes.

A randomized clinical trial of two single-dose treatments for paucibacillary leprosy.

We compared 2 single-dose regimens for the treatment of paucibacillary leprosy in a randomized clinical trial in Zaïre. The regimens were: C2 (rifampicin 40 mg/kg and 1200 mg clofazimine once) and C4 (rifampicin 40 mg/kg, clofazimine 100 mg, DDS 100 mg and ethionamide 500 mg once). An analysis of the results of patients enrolled between May 1987 and December 1988, with a maximum follow-up of 4 years, is presented. A total of 622 patients were enrolled and 14 paucibacillary and 1 multibacillary relapses occurred. The overall paucibacillary relapse rate was 2.4 per 100 person years. This relapse rate was higher for older patients as well as for patients with 3 or more lesions. The probability of cure at 3 years is 0.816 for C2 and 0.823 for C4, the difference not being statistically significant. The probability of cure at 3 years with either regimen is higher for patients with 1 or 2 lesions (0.872) than for patients with 3 or more lesions (0.787), and it is higher for patients with a bacterial index of 0 (0.831) than for patients with a bacterial index of 1 (0.699). These results are compared to other studies. We also discuss the potential of single-dose treatment regimens for paucibacillary leprosy.

Detection of Mycobacterium leprae by the polymerase chain reaction in nasal swabs of leprosy patients and their contacts.

Nose swabs from 4 paucibacillary (PB) and 8 multibacillary (MB) leprosy patients and their contacts were tested for the presence of Mycobacterium leprae by two polymerase chain reactions (PCR); 30% of the samples contained inhibitors for the PCR, 1 of 52 (1.9%) swabs and 13 of 164 (7.9%) swabs were positive for M. leprae among contacts of PB and MB patients, respectively. Since this difference is not significant, and some positives were found among contacts of MB patients treated and cured of their infection, it is concluded that the observed infections are community acquired.

Polymerase chain reaction amplifying DNA coding for species-specific rRNA of Mycobacterium leprae.

The sensitivity of the polymerase chain reaction (PCR) on the DNA coding for the species-specific fragment of 16S rRNA of Mycobacterium leprae studied on mouse foot pad harvests and human skin biopsies varies widely between 1 and 3 x 10(4) organisms. This is probably the result of variations in the proportions of organisms with sufficiently intact DNA suitable for PCR. Preserving human skin biopsies for 3 weeks at an ambient temperature even after boiling for 6 minutes gives rise to a 10-fold decrease in sensitivity. Fixation of tissues in formol 10% or Lowy fixative or preserving in Dubos OAA broth is very harmful to the PCR, mainly due to the enhancement of an inhibitory effect on the PCR reaction. For preservation, the best choice at the moment seems to be alcohol 70%. Sample preparation of five cycles of freeze-boiling is simple and generally more efficient than proteinase K treatment and DNA extraction.

Ambulatory treatment of multibacillary leprosy with a regimen of 8 months duration.

An ambulatory treatment regimen for multibacillary leprosy, of 34 weeks duration composed of 8 weeks daily supervised rifampicin, ethionamide (ETH), dapsone (DDS) and clofazimine (CLO) followed by 26 weeks of unsupervised ETH, DDS and CLO, introduced in 1983 has been evaluated; 268 patients were followed for a mean of 4.4 years and a total of 1188 patient years. The relapse rate was 0.33 per 100 patient years of follow up. The reduction of the duration of the combined administration of RMP + ETH reduced the hepatotoxicity to 1.4%. It is possible that both phases of the regimen studied could still be reduced, however, in the near future ETH will be replaced by alternative bactericidal drugs, avoiding the hepatotoxicity.

Treatment of multibacillary leprosy with a regimen of 13 weeks duration.

In a prospective study 559 multibacillary patients in Zaire were treated for 13 weeks with twice weekly rifampicin (600 mg) and daily ethionamide (500 mg) and dapsone (100 mg), 13-RED, or clofazimine (100 mg), 13-REC. The patients were followed for a total of 1418 person years, mean 3.2 years. The incidence of hepatitis was 3.3%. The incidence of relapses was 0.28 per 100 person years. Relapses were due to drug-sensitive organisms. In patients who received the same drug regimens but with a reduced dosage of ethionamide to 5 mg/k bodyweight, the incidence of hepatitis was significantly lower but the relapse rate was 7.8 per 100 person years of follow-up in the RED group, no relapses were diagnosed in the REC group. It is concluded that by the use of potent antileprosy drugs in suitable combinations and dosages, it will be possible to shorten the duration of antibacterial treatment in multibacillary leprosy to 3 months.

Molecular biology in diagnostic microbiology. PCR on Mycobacterium leprae.

The polymerase chain reaction (PCR) has already produced several hundreds of papers. Alternative procedures for diagnostic purposes based on nucleic acid detection do exist but have until now found less application. Problems with the PCR are discussed. It is proposed that the diagnostic microbiology laboratory has a section devoted to PCR for the diagnosis of diseases whose etiologic agent can "almost not" be cultured such as (for Flanders) Mycoplasma pneumoniae, Chlamydia pneumoniae, Toxoplasma gondii, EB virus and some other agents in particular specimens. In this setting the PCR would only be performed on selected, clinically justified samples, in close collaboration between clinician and microbiologist. PCR will evidently play an important role in research. Illustration is given of PCR applied for the detection Mycobacterium leprae.

Anti-Mycobacterium leprae activity of several quinolones studied in the mouse.

The anti-Mycobacterium leprae activity of several fluoroquinolones (A-56619, A-56620, ofloxacin, fleroxacin, lomefloxacin, temafloxacin, tosufloxacin, and PD-117596) was studied in the mouse. In a dosage of 150 mg/kg administered daily, A-56619 is active and A-56620 is inactive against M. leprae. Ofloxacin administered daily for 2 weeks at 300 mg/kg is bactericidal. The minimal effective dose of PD-117596, lomefloxacin and temafloxacin is less than 37.5 mg/kg. When administered at 300 mg/kg at monthly intervals temafloxacin, PD-117596, and ofloxacin are bacteriostatic; while fleroxacin and lomefloxacin are bactericidal. Tosufloxacin is less active than the other quinolones included in the present study.

A controlled therapeutic trial in paucibacillary leprosy comparing a single dose of rifampicin with a single dose of rifampicin followed by one year of daily dapsone. The Collaborative Study Group for the Treatment of Leprosy in Zaire.

The cure rates of two treatment regimens in PB leprosy were compared in a prospective randomized trial: treatment U consisting of a single dose of rifampicin 40 mg/K bodyweight, and treatment A of rifampicin 1500 mg in a single dose, followed by one year of daily dapsone 100 mg. In patients with a BI = 0, the cure rates evaluated on the basis of histopathology of skin biopsies, were identical for the two regimens but in patients with a BI = 1, cure and relapse rates were unacceptable. For this reason and particularly the need to separate patients on the basis of the BI in skin biopsies, the single dose regimen does not appear to be suited for wide-scale application.