Aim: To select a polyethylene-degrading micro-organism and to study the factors affecting its biodegrading activity. Methods and Results: A thermophilic bacterium Brevibaccillus borstelensis strain 707 (isolated from soil) utilized branched low-density polyethylene as the sole carbon source and degraded it. Incubation of polyethylene with B. borstelensis (30 days, 50°C) reduced its gravimetric and molecular weights by 11 and 30% respectively. Brevibaccillus borstelensis also degraded polyethylene in the presence of mannitol. Biodegradation of u.v. photo-oxidized polyethylene increased with increasing irradiation time. Fourier Transform Infra-Red (FTIR) analysis of photooxidized polyethylene revealed a reduction in carbonyl groups after incubation with the bacteria. Conclusions: This study demonstrates that polyethylene -considered to be inert -can be biodegraded if the right microbial strain is isolated. Enrichment culture methods were effective for isolating a thermophilic bacterium capable of utilizing polyethylene as the sole carbon and energy source. Maximal biodegradation was obtained in combination with photo-oxidation, which showed that carbonyl residues formed by photo-oxidation play a role in biodegradation. Brevibaccillus borstelensis also degraded the CH 2 backbone of nonirradiated polyethylene. Significance and Impact of the Study: Biodegradation of polyethylene by a single bacterial strain contributes to our understanding of the process and the factors affecting polyethylene biodegradation.

The objective of this study was to determine the population pharmacokinetic parameters of levofloxacin, gatifloxacin, and moxifloxacin following multiple oral doses. Twenty-nine patients with tuberculosis at the University Hospital in Vitória, Brazil, participated. Subjects received multiple doses of one drug (levofloxacin, 1,000 mg daily, or gatifloxacin or moxifloxacin, 400 mg daily) as part of a 7-day study of early bactericidal activity. Serum samples were collected over 24 h after the fifth dose and assayed using validated highperformance liquid chromatography assays. Concentration-time data were analyzed using noncompartmental, compartmental, and population methods. The three drugs were well tolerated. Levofloxacin produced the highest maximum plasma concentrations (median, 15.55 g/ml; gatifloxacin, 4.75 g/ml; moxifloxacin, 6.13 g/ml), largest volume of distribution (median, 81 liters; gatifloxacin, 79 liters; moxifloxacin, 63 liters), and longest elimination half-life (median, 7.4 h; gatifloxacin, 5.0 h; moxifloxacin, 6.5 h). A one-compartment model, with or without weight as a covariate, adequately described the data. Postmodeling simulations using median population parameter estimates closely approximated the median values from the original data. Area under the concentration-time curve/MIC ratios for free drug were high. All three quinolones showed favorable pharmacokinetic and pharmacodynamic indices, with the most favorable results in this population being seen with levofloxacin at the comparative doses used.Fluoroquinolones are bactericidal against Mycobacterium tuberculosis and are employed as second-line agents for the treatment of tuberculosis (TB) in cases of patient intolerance or mycobacterial resistance (multidrug-resistant TB) (1, 15). Increasingly, these drugs are being evaluated as first-line agents for newly diagnosed, drug-susceptible TB (2, 9). The pharmacokinetics (PK) of levofloxacin, gatifloxacin, and moxifloxacin have been characterized in healthy volunteers and in several clinical settings, including a previous PK study of ofloxacin (the racemic mixture that includes levofloxacin) in patients with TB (4, 9, 16).In our previous report, we described the early bactericidal activity of isoniazid, levofloxacin, gatifloxacin, and moxifloxacin in patients with TB (9). In this study, we further explored the PK of these fluoroquinolones in TB patients and developed structural models of their behavior, and this report provides population PK parameter estimates that can be used in simulations of these three quinolones in TB patients. MATERIALS AND METHODSStudy design. HIV-uninfected 18-to 65-year-old Brazilian adults with newly diagnosed smear-positive TB who weighed more than 75% of their ideal body weight and who had relatively normal hematologic, renal, and hepatic function were eligible (9). The institutional review boards of the Universidade Federal do Espírito Santo and Case Western Reserve University approved the protocol. Patients gave written informed consent.Patients were randomized ...

We examined sputum bacterial loads in adults with newly diagnosed tuberculosis using quantitative culture and time-until-positive (DTP) culture in BACTEC 460. Patients with cavitary disease had higher CFU levels than those without cavities and shorter DTPs. Within radiographic strata of moderately and far advanced tuberculosis, higher CFU counts were associated with cavitary disease.

Rationale: Cavitary disease and delayed culture conversion have been associated with relapse. Combining patient characteristics and measures of bacteriologic response might allow treatment shortening with current drugs in some patients. Objectives: To assess whether treatment could be shortened from 6 to 4 months in patients with noncavitary tuberculosis whose sputum cultures converted to negative after 2 months. Methods: This study was a randomized, open-label equivalence trial. HIV-uninfected adults with noncavitary tuberculosis were treated daily with isoniazid, rifampin, pyrazinamide, and ethambutol for 2 months, followed by 2 months of isoniazid and rifampin. After 4 months, patients with drug-susceptible TB whose sputum cultures on solid media were negative after 8 weeks of treatment were randomly assigned to continue treatment for 2 more months or to stop treatment. Patients were followed for relapse for 30 months after beginning treatment. Measurements and Main Results: Enrollment was stopped by the safety monitoring committee after 394 patients were enrolled due to apparent increased risk for relapse in the 4-month arm. A total of 370 patients were eligible for per protocol analysis. Thirteen patients in the 4-month arm relapsed, compared with three subjects in the 6-month arm (7.0 vs. 1.6%; risk difference, 0.054; 95% confidence interval with Hauck-Anderson correction, 0.01-0.10). Conclusion: Shortening treatment from 6 to 4 months in adults with noncavitary disease and culture conversion after 2 months using current drugs resulted in a greater relapse rate. The combination of noncavitary disease and 2-month culture conversion was insufficient to identify patients with decreased risk for relapse.

A particular strain of M. abscessus ssp. massiliense was associated with a prolonged epidemic of postsurgical infections in seven Brazilian states, suggesting that this strain may be distributed in Brazilian territory and better adapted to cause surgical-site infections.