Evolution of microbial aerosol behaviour in heating, ventilating and air-conditioning systems--quantification of Staphylococcus epidermidis and Penicillium oxalicum viability

The aim of this study was to develop an experimental set-up and a methodology to uniformly contaminate several filter samples with high concentrations of cultivable bacteria and fungi. An experimental set-up allows contaminating simultaneously up to four filters for range of velocities representative of heating, ventilating and air-conditioning systems. The test aerosol was composed of a microbial consortium of one bacterium (Staphylococcus epidermidis) and one fungus (Penicillium oxalicum) and aerosol generation was performed in wet conditions. Firstly, the experimental set-up was validated in regards to homogeneity of the air flows. The bioaerosol was also characterized in terms of number and particle size distribution using two particle counters: optical particle counter Grimm 1.109 (optical diameters) and TSI APS 3321 (aerodynamic diameters). Moreover, stabilities of the number of particles generated were measured. Finally, concentrations of cultivable microorganisms were measured with BioSamplers (SKC) downstream of the four filters.

Evolution of microbial aerosol behaviour in heating, ventilating and air-conditioning systems--quantification of Staphylococcus epidermidis and Penicillium oxalicum viability

The aim of this study was to develop an experimental set-up and a methodology to uniformly contaminate several filter samples with high concentrations of cultivable bacteria and fungi. An experimental set-up allows contaminating simultaneously up to four filters for range of velocities representative of heating, ventilating and air-conditioning systems. The test aerosol was composed of a microbial consortium of one bacterium (Staphylococcus epidermidis) and one fungus (Penicillium oxalicum) and aerosol generation was performed in wet conditions. Firstly, the experimental set-up was validated in regards to homogeneity of the air flows. The bioaerosol was also characterized in terms of the number and particle size distribution using two particle counters: optical particle counter Grimm 1.109 (optical diameters) and TSI APS 3321 (aerodynamic diameters). Moreover, stabilities of the number of particles generated were measured. Finally, concentrations of cultivable microorganisms were measured with BioSamplers SKC downstream of the four filters.

[Prospective study of effectiveness. Reoperation (re-TUR) in superficial bladder carcinoma]

To assess the rate of residual cancer after transurethral resection (TUR) of superficial bladder cancer, a prospective study was carried out. All patients with transitional cell cancer (TCC) stage pTa-pT1 underwent a repeat TUR (ReTUR) within 6-8 weeks. Sites and rates of tumors found during ReTUR were documented as well as the morbidity of the ReTUR. Of a total of 192 TUR, superficial TCC was found in 124 cases; 83 underwent ReTUR according to the study protocol. Residual tumor was detected in 27% of pTa and 53% of pT1 tumors. Worsening of grading or T stage was found in 8%. Of the tumors detected by ReTUR, 81% were localized at the site of the first TUR. In this prospective study, residual tumor formation was detected in a high percentage. Routine ReTUR is therefore recommended in superficial bladder cancer except solitary pTaGI lesions.