Introduction: Lymph node tuberculosis (TB) is the leading cause of extrapulmonary tuberculosis and is the most frequently identified type in Aguascalientes, Mexico. Conventional diagnosis has serious limitations for rapid detection of extrapulmonary tuberculosis in clinical samples. Here PCR and modified FISH have been tested as complementary diagnosis methods for extrapulmonary tuberculosis. Methodology: The specific insertion sequence IS6110 for Mycobacterium tuberculosis complex was used to perform PCR and build DNA and PNA FISH probes (20bp). PCR and modified DNA and PNA FISH assays were performed to evaluate 41 lymph node paraffin-embedded tissue samples, in comparison with the histopathology diagnosis, which was considered the gold standard (22 positive and 19 negative). Results: In comparison with histopathology diagnosis PCR showed 62.5 % sensitivity and 77.8 % specificity (χ 2 = 4.583 p< 0.05). Modified DNA FISH showed 71.4% sensitivity and 84.6% specificity (χ 2 = 11.21 p< 0.05). PNA FISH showed 66.7% sensitivity and 60.0% specificity (χ 2 = 2.93 p> 0.05). Ziehl Neelsen stain was positive in only four cases of 22 lymph node samples positive to histopathology. In contrast, PCR and modified DNA FISH were positive in 20 cases of the same group. The negative cases were coincident in all tests. Conclusions: PCR and DNA FISH showed a significant increase in the number of cases detected and also showed higher sensitivity and specificity compared with data reported by traditional methodology. In developing countries, these techniques could help to complement the early diagnosis and timely treatment of extrapulmonary tuberculosis.

Treatment of wastewater containing high phenol concentrations (up to 4,000 mg/l, 1,600 kg/ha.d) in laboratory-scale stabilisation ponds enriched with activated sludge was studied. Phenol was biodegraded efficiently, even when fed as the sole carbon source. At influent concentrations of 1,000, 1,300, 1,600, 1,900, 2,500, 3,000 and 4,000 mg/l of phenol (loading rates of 400, 520, 640, 760, 1,000, 1,200 and 1,600 kg phenol/ha.d), the phenol removal efficiencies were 92, 89, 81, 81, 76, 65 and 22%, respectively. At 4,000 mg/l of phenol, the enriched ponds were significantly inhibited. The maximum phenol removal rate observed was 780 kg/ha.d, which is 7.7 times higher than the maximum value reported for attached-growth waste stabilisation ponds. All along the experiments, the enriched ponds showed removal rates 1.8-20.5 times higher than the values observed in control pond (not enriched). The results suggest that enrichment is an effective method to increase xenobiotic removal rates of stabilisation ponds.

Treatment of wastewater containing phenol using laboratory scale waste stabilisation ponds enriched with activated sludge was studied. After enrichment, the efficiency of these ponds under high phenol loading rates (i.e. up to 408 kg phenol ha(-1) day(-1)) was studied. At phenol loading rates of 6, 52, 312, 636 and 972 COD ha(-1) day(-1), the phenol removal efficiencies were 77, 69, 76, 59 and 52%, respectively. The results suggest that enrichment is an effective potential method to increase the removal capability of facultative ponds, not only or easily biodegradable compounds but also for xenobiotics.

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