OBJECTIVES: Highly pathogenic viruses such as Ebola virus are a threat to routine laboratory workers. Inactivation procedures with Triton X-100 0.1% and/or heat are currently recommended, but have unknown effects on the accuracy of serological testing. Furthermore, virus inactivation by Triton X-100 0.1% was shown to be ineffective in serum. This study aimed to demonstrate virus inactivation in serum by Triton X-100 1% and maintained accuracy of serological testing. METHODS: A panel of 19 serological tests was run on patient serum samples after treatment with Triton X-100 1%, 0.1%, and 0.1% + heat inactivation at 60°C for 1h. Mean differences between measurements (bias) were calculated applying the Bland-Altman method. To determine effectiveness of virus inactivation, herpes simplex virus 1 (HSV-1) was spiked into medium containing 90% or 1% serum, and treated with Triton X-100 0.1% or 1%. Infectious titers were then determined on Vero cells. RESULTS: Serological measurements showed good agreement between controls and samples treated with Triton X-100 0.1% and 1%, with an estimated bias of -0.6±9.2% (n=258) and -0.1±18.6% (n=174), respectively. Discordant qualitative results were rare. Conversely, heat inactivation alone, and combined with Triton X-100 0.1% triggered a bias of 17.5±66.4% (n=200) and 37.9±79.8% (n=160), respectively. Triton X-100 1% completely inactivated HSV-1 in 1% and 90% serum while Triton X-100 0.1% failed to do so in 90% serum. CONCLUSIONS: Unlike heat inactivation, Triton X-100 1% enabled accurate serological testing and completely inactivated HSV-1 in serum. This simple method could allow safe routine serological diagnostics in high-risk patients. REFERENCE: Remy MM, et al. Effective chemical virus inactivation of patient serum compatible with accurate serodiagnosis of infections. Clin Microbiol Infect. 2018 Oct 27. pii: S1198-743X(18)30721-3. doi: 10.1016/j.cmi.2018.10.016. ----------------------------------------------------------- Sigue este Blog en Facebook y Twitter Ayúdanos a traducir las fichas de seguridad de microorganismos. www.seguridadbiologica.blogspot.com ----------------------------------------------------------- […]

In Mali, the incidence of tuberculosis (TB) is estimated at 56 cases per 100 000 people, with a prevalence of multidrug-resistant TB in new cases of 1.7% (range, 0.3-3.1%) and in retreatment cases of 17% (range, 4.4-30%). Appropriate biosafety conditions for performing routine TB culture and antimicrobial susceptibility testing have been lacking. In 2015, a biosafety level 3 (BSL3) laboratory set up in a shipping container was donated to the Malian Ministry of Health and Public Hygiene to provide capacity for TB testing. This laboratory is now managed by Malian laboratory staff and is processing samples at the national level. We explain the necessary steps for establishing and running a BSL3 laboratory. Despite the acute need for functioning and sustainable BSL3 laboratories, low- and middle-income countries are faced with a complex process and must overcome many challenges. REFERENCE: Kouriba B, Ouwe Missi Oukem-Boyer O, Traoré B, Touré A, Raskine L, Babin FX. Installing biosafety level 3 containment laboratories in low- and middle-income countries: challenges and prospects from Mali's experience. New Microbes New Infect. 2018 Jun 20;26:S74-S77. doi: 10.1016/j.nmni.2018.05.011. ----------------------------------------------------------- Sigue este Blog en Facebook y Twitter Ayúdanos a traducir las fichas de seguridad de microorganismos. www.seguridadbiologica.blogspot.com ----------------------------------------------------------- […]

BACKGROUND: Biofilms that develop on dry surfaces in the healthcare environment have increased tolerance to disinfectants. We compared the activity of formulated oxidizing disinfectants versus products containing only active ingredients against Staphylococcus aureus dry surface biofilm (DSB). METHODS: DSB was grown in the CDC bioreactor with alternating cycles of hydration and dehydration. Disinfectant efficacy was tested before and after treatment with neutral detergent for 30 seconds and in the presence or absence of standardized soil. Biofilms were treated for 5 minutes with peracetic acid (Surfex and Proxitane), hydrogen peroxide (Oxivir and 6% H2O2 solution) and chlorine (Chlorclean and sodium dichloroisocyanurate [SDIC] tablets). Residual biofilm viability and mass were determined by plate culture and protein assay respectively. FINDINGS: Biofilm viability was reduced by 2.8 Log10 for the chlorine-based products and by 2 Log10 for Proxitane but these products failed to kill any biofilm in the presence of the soil. In contrast, the formulated Surfex completely inactivated biofilm (6.3log10 reduction in titre) in the presence of soil. H2O2 products had little effect against DSB. Biofilm mass removed in the presence and absence of soil was <30% by chlorine and approximately 65% by Surfex. Detergent treatment prior to disinfection had no effect. CONCLUSION: The additives in fully formulated disinfectants can act synergistically with active ingredients and thus increase biofilm killing whilst decreasing the adverse effect of soil. We suggest that purchasing officers seek efficacy testing results and consider whether efficacy testing has been conducted in the presence of biological soil and/or biofilm. REFERENCE: Chowdhury D, et al. The effect of disinfectant formulation and organic soil on the efficacy of oxidising disinfectants against biofilms. J Hosp Infect. 2018 Oct 26. pii: S0195-6701(18)30556-5. doi: 10.1016/j.jhin.2018.10.019. ----------------------------------------------------------- Sigue este Blog en Facebook y Twitter Ayúdanos a traducir las fichas de seguridad de microorganismos. www.seguridadbiologica.blogspot.com ----------------------------------------------------------- […]

Formaldehyde (FA) is a familiar indoor air pollutant found in everything from cosmetics to clothing, but its impact on the middle ear is unknown. This study investigated whether FA causes cytotoxicity, inflammation, or induction of apoptosis in human middle ear epithelial cells (HMEECs). Cell viability was investigated using the trypan blue assay and a cell counting kit (CCK-8) in HMEECs treated with FA for 4 or 24 h. The expression of genes encoding the inflammatory cytokine tumor necrosis factor alpha (TNF-α) and mucin (MUC5AC) was analyzed using RT-PCR. Activation of the apoptosis pathway was determined by measuring mitochondrial membrane potential (MMP), cytochrome oxidase, caspase-9/Mch6/Apaf 3, and Caspase-Glo® 3/7 activities. The CCK-8 assay and trypan blue assay results showed a reduction in cell viability in FA-treated HMEECs. FA also increased the cellular expression of TNF-α and MUC5AC and reduced the activities of MMP and cytochrome oxidase. Caspase-9 activity increased in cells stimulated for 4 h, as well as caspase-3/7 activity in cells stimulated for 24 h. The decreased cell viability, the induction of inflammation and mucin gene expression, and the activation of the apoptosis pathway together indicate a link between environmental FA exposure and the development of otitis media. REFERENCE: Kim SH, et al. Effect of Formaldehyde on Human Middle Ear Epithelial Cells. Biomed Res Int. 2018 Mar 26;2018:6387983. doi: 10.1155/2018/6387983. eCollection 2018. ----------------------------------------------------------- Sigue este Blog en Facebook y Twitter Ayúdanos a traducir las fichas de seguridad de microorganismos. www.seguridadbiologica.blogspot.com ----------------------------------------------------------- […]

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