Ozone as an alternative decontamination process for N95 facemask and biosafety gowns.

COVID-19 pandemic created a global shortage of medical protective equipment. Here, we considered ozone (O3) a disinfectant alternative due to its potent oxidative activity against biological macromolecules. The O3 decontamination assays were done using SARS-CoV-2 obtained from patients to produce artificial contamination of N95 masks and biosecurity gowns. The quantification of SARS-CoV-2 was performed before and after exposing the samples to different ozone gas concentrations for times between 5 and 30 min. Viral loads as a function of the O3 exposure time were estimated from the data obtained by the RT-PCR technique. The genetic material of the virus was no longer detected for any tested concentrations after 15 min of O3 exposure, which means a disinfection Concentration-Time above 144 ppm min. Vibrational spectroscopies were used to follow the modifications of the polymeric fibers after the O3 treatment. The results indicate that the N95 masks could be safely reused after decontamination with treatments of 15 min at the established O3 doses for a maximum of 6 cycles.

Human leukocyte antigen typing in tuberculous rheumatism: Poncet's disease.

SETTING: Tuberculous rheumatism (Poncet's disease) is a reactive polyarthropathy associated with extra-pulmonary and pulmonary tuberculosis (TB) without evidence of mycobacterial infection of the involved joints. As all patients with TB do not present with this peculiar clinical feature, a genetic susceptibility is suspected. OBJECTIVE: To determine the major histocompatibility complex (MHC) class I and II alleles in Mexican mestizo patients with Poncet's disease. DESIGN: In this case-control study of 16 Mexican mestizo patients diagnosed with Poncet's disease and 99 ethnically matched healthy controls, high resolution human leukocyte antigen (HLA) typing was performed for HLA-A, B, DR and DQ by polymerase chain reaction. HLA-DRB1 and HLA-DQB1 subtypes were performed by sequence-specific oligonucleotide probe hybridization. RESULTS: A significantly increased frequency of HLA-B27 (corrected P = 0.01) and DQB1*0301 (corrected P = 0.0009) alleles and decreased frequency of HLA-DQB1*0302 (corrected P = 0.00001) were identified in patients compared to healthy controls. CONCLUSION: These data suggest that genes located within the MHC may play a role in the susceptibility to Poncet's disease in patients diagnosed with TB.