Sputum Mycobacterium tuberculosis mRNA as a Marker of Bacteriologic Clearance in Response to Antituberculosis Therapy▿

mRNA is a marker of cell viability. Quantifying Mycobacterium tuberculosis mRNA in sputum is a promising tool for monitoring response to antituberculosis therapy and evaluating the efficacy of individual drugs. mRNA levels were measured in sputum specimens from patients with tuberculosis (TB) receiving monotherapy in an early bactericidal activity study of fluoroquinolones and in those receiving a standard rifampin-based regimen in an interleukin-2 (IL-2) trial. In the early bactericidal activity study, sputum for quantitative culture and mRNA analysis was collected for 2 days before and daily during 7 days of study drug administration. In the IL-2 trial, sputum was collected for quantitative culture, Bactec 460 liquid culture, and mRNA analysis throughout the intensive treatment phase. RNA was isolated from digested sputum and tested in quantitative reverse transcription-PCR assays for several gene targets. mRNA for the glyoxylate cycle enzyme isocitrate lyase declined at similar rates in patients receiving isoniazid, gatifloxicin, levofloxacin, and moxifloxacin monotherapy. Isocitrate lyase mRNA correlated highly with CFU in sputum prior to therapy and during 7 days of monotherapy in all treatment arms. Isocitrate lyase mRNA was detectable in sputum of culture-positive TB patients receiving a rifampin-based regimen for 1 month. At 2 months, sputum for isocitrate mRNA correlated more closely with growth in liquid culture than did growth on solid culture medium. Data suggest that isocitrate lyase mRNA is a reliable marker of M. tuberculosis viability

An immunopathologic study of the bovine prepuce

The prepuces of 83 slaughtered bulls with macroscopically normal reproductive tracts were examined. Some bulls had been vaccinated on several occasions against Campylobacter fetus. Mean concentrations of intrapreputial immunoglobulins (Ig) in 27 bulls were IgG1--1.8 plus or minus 5.2; IgA--0.16 plus or minus 0.15; and IgM--0.24 plus or minus 0.24 mg/ml. High concentrations of IgG2 in some bulls precluded precise estimation but mean concentration was in excess of 11.0 mg/ml (range 0 to 20+ mg/ml). Mean prevalences of class specific, immunoperoxidase-labelled plasma cells in the preputial dermis of 35 bulls were IgG--39.0 plus or minus 9.3; IgA--16.6 plus or minus 6.6; and IgM--2.2 plus or minus 1.8 labelled cells/100 nuclei. The prevalence of IgG labelled cells in the preputial dermis was, however, negatively correlated with the concentration of intrapreputial IgG (IgG1 + IgG2). Except for an apparently lower intrapreputial Ig concentration in 14 Trichomonas foetus-infected bulls than in negative ones, there were no correlations between intrapreputial immunoglobulin concentration, histological findings, and age, infection, or vaccination status of the bulls