784. Efficiency of Quaternary Ammonium Disinfectants against SARS-CoV-2 and Coronavirus 229E

Background The recent pandemic of CoVid19 has increased our need to assess the impact of disinfectants on the inactivation of human coronaviruses. The goals of this study were 1) quantify the disinfection of SARS-CoV-2 and human coronavirus 229 inactivations by various quaternary ammonium formulations, and 2) demonstrate the impact of disinfectants on preventing fomite-to-finger transfer of coronaviruses. Methods We compared the inactivation of both SARS-Covid -2 and coronavirus 229E suspended in 5% fetal calf sera and dried on both metal and plastic surfaces. In addition, studies were conducted with a silinated quaternary ammonium compound that left a residual on the surface. Studies were also conducted on the finger transfer of coronavirus from various surfaces. The virus was allowed to dry on the surface for 30 minutes, then a transfer was conducted by placing the finger pad directly onto the contaminated surface. The finger was tested for the virus. The study was then repeated with virus-contaminated porcelain surfaces that were sprayed with a quaternary product or placed on a surface with a quaternary ammonium compound that left a residual. Results Several readily available quaternary ammonium formulations were evaluated and proved to be effective with greater than a 99.9% reduction in titer after drying on both metal and plastic surfaces. In addition, a silinated quaternary ammonium compound that left a residual on the surface was capable of inactivating SARS-CoV-2 for at least seven days after application. Studies on the finger transfer of coronavirus from various surfaces showed that the amount of virus transfer to the finger varied from 0.46 to 49.0% depending upon the surface. Little or no virus transfer occurred from treated surfaces compared to the untreated controls. In addition, coronavirus 229E appears to be a good model for use in disinfection assessments for SARS-CoV-2. Conclusion Our results demonstrate that various quaternary ammonium disinfectant formulations are effective against human coronaviruses. Finger transfer tests showed that transmission of coronavirus from surfaces can be prevented, reducing the risk of fomite transmission. Coronavirus 229E appears to be a good model for use in disinfection assessments for SARS-CoV-2. Disclosures Charles P. Gerba, Ph.D., Allied Biosciences (Grant/Research Support)Behr (Grant/Research Support)Corning Inc. (Grant/Research Support)PPG (Grant/Research Support)Procter and Gamble (Other Financial or Material Support, donation)Rickett and Coleman (Grant/Research Support)

Genitourinary Tissue Engineering: Reconstruction and Research Models

Tissue engineering is an emerging field of research that initially aimed to produce 3D tissues to bypass the lack of adequate tissues for the repair or replacement of deficient organs. The basis of tissue engineering protocols is to create scaffolds, which can have a synthetic or natural origin, seeded or not with cells. At the same time, more and more studies have indicated the low clinic translation rate of research realised using standard cell culture conditions, i.e., cells on plastic surfaces or using animal models that are too different from humans. New models are needed to mimic the 3D organisation of tissue and the cells themselves and the interaction between cells and the extracellular matrix. In this regard, urology and gynaecology fields are of particular interest. The urethra and vagina can be sites suffering from many pathologies without currently adequate treatment options. Due to the specific organisation of the human urethral/bladder and vaginal epithelium, current research models remain poorly representative. In this review, the anatomy, the current pathologies, and the treatments will be described before focusing on producing tissues and research models using tissue engineering. An emphasis is made on the self-assembly approach, which allows tissue production without the need for biomaterials.

Evaluation of stability and inactivation methods of SARS-CoV-2 in context of laboratory settings

The novel coronavirus SARS-CoV-2 is the causative agent of the acute respiratory disease COVID-19, which has become a global concern due to its rapid spread. Laboratory work with SARS-CoV-2 in a laboratory setting was rated to biosafety level 3 (BSL-3) biocontainment level. However, certain research applications in particular in molecular biology require incomplete denaturation of the proteins, which might cause safety issues handling contaminated samples. In this study, we evaluated lysis buffers that are commonly used in molecular biological laboratories for their ability to inactivate SARS-CoV-2. In addition, viral stability in cell culture media at 4 °C and on display glass and plastic surfaces used in laboratory environment was analyzed. Furthermore, we evaluated chemical and non-chemical inactivation methods including heat inactivation, UV-C light, addition of ethanol, acetone-methanol, and PFA, which might be used as a subsequent inactivation step in the case of insufficient inactivation. We infected susceptible Caco-2 and Vero cells with pre-treated SARS-CoV-2 and determined the tissue culture infection dose 50 (TCID50) using crystal violet staining and microscopy. In addition, lysates of infected cells and virus containing supernatant were subjected to RT-qPCR analysis. We have found that guanidine thiocyanate and most of the tested detergent containing lysis buffers were effective in inactivation of SARS-CoV-2, however, the M-PER lysis buffer containing a proprietary detergent failed to inactivate the virus. In conclusion, careful evaluation of the used inactivation methods is required especially for non-denaturing buffers. Additional inactivation steps might be necessary before removal of lysed viral samples from BSL-3.

Understanding the Fundamental Basis for Biofilm Formation on Plastic Surfaces: Role of Conditioning Films

Graphical AbstractThe formation and composition of conditioning films.

Sampling efficiency of Candida auris from healthcare surfaces: culture and nonculture detection methods

Sponges and swabs were evaluated for their ability to recover Candida auris dried 1 hour on steel and plastic surfaces. Culture recovery ranged from <0.1% (sponges) to 8.4% (swabs), and cells detected with an esterase activity assay revealed >50% recovery (swabs), indicating that cells may enter a viable but nonculturable state.

Persistence of SARS-CoV-2 in deceased patients and safe handling of infected bodies

This article analyzes the literature on SARS-CoV-2 persistence in the corpses of patients infected with COVID-19, possible routes of viral transmission from the bodies and biosafety measures to prevent the spread of the infection. SARS-CoV-2 persists for quite long in the tissues and bodily fluids of decedents with COVID-19 and on various surfaces. The longest viability of the virus is on stainless steel and plastic surfaces that come in contact with the infected body. Autopsies on decedents with COVID-19 must be performed at specially conditioned facilities. Medical and forensic pathologists and other mortuary workers must adhere to stringent biosafety requirements.

Self-Assembling Quaternary Ammonium Sulfonamide Antimicrobials

A series of novel sulfonamide based quaternary ammonium (QUAT’s) antimicrobials containing a variety of chemical anchors R-SO2-NH-(CH2)3-N(CH3)2-(CH2)3-Y (where R = alkyl or aryl and Y = organosilane (Si(OMe)3), organophosphorus (P(O)(OR1)) and benzophenone (-OC6H4-C(O)-C6H5)) were used to immobilize them on different substrates. Sulfonamide organosilane QUAT’s were immobilized on to textiles substrates, whereas benzophenone QUAT’s were used to exclusively coat plastic surfaces (polyethylene (PE), and polyvinylchloride (PVC)), and organophosphorus QUAT’s were prepared for testing on metal surfaces (stainless steel). The covalently attached antimicrobial coatings were found to kill gram +ve and -ve bacteria on contact, hindering their attachment and colonization without any leachate. The partially water soluble sulfonamide QUAT’s presented are readily prepared, easy to apply and are relatively inexpensive. Textile samples were prepared by immersion in a MeOH:H2O (30:70) solution of organosilane QUAT’s followed by curing/drying at room temperature for 2 – 24 hours. Plastic samples were prepared by electrospraying an EtOH:H2O (10:90) solution containing benzophenone QUAT’s followed by UV curing using for 2 – 5 minutes. All samples showed a 100% reduction (107– 106 cells) of viable Arthrobacter, S. aureus, and E.coli after 3 hours of contact time and maintained their activity over 24 hours versus the control (untreated) samples.

Self-Assembling Quaternary Ammonium Sulfonamide Antimicrobials

A series of novel sulfonamide based quaternary ammonium (QUAT’s) antimicrobials containing a variety of chemical anchors R-SO2-NH-(CH2)3-N(CH3)2-(CH2)3-Y (where R = alkyl or aryl and Y = organosilane (Si(OMe)3), organophosphorus (P(O)(OR1)) and benzophenone (-OC6H4-C(O)-C6H5)) were used to immobilize them on different substrates. Sulfonamide organosilane QUAT’s were immobilized on to textiles substrates, whereas benzophenone QUAT’s were used to exclusively coat plastic surfaces (polyethylene (PE), and polyvinylchloride (PVC)), and organophosphorus QUAT’s were prepared for testing on metal surfaces (stainless steel). The covalently attached antimicrobial coatings were found to kill gram +ve and -ve bacteria on contact, hindering their attachment and colonization without any leachate. The partially water soluble sulfonamide QUAT’s presented are readily prepared, easy to apply and are relatively inexpensive. Textile samples were prepared by immersion in a MeOH:H2O (30:70) solution of organosilane QUAT’s followed by curing/drying at room temperature for 2 – 24 hours. Plastic samples were prepared by electrospraying an EtOH:H2O (10:90) solution containing benzophenone QUAT’s followed by UV curing using for 2 – 5 minutes. All samples showed a 100% reduction (107– 106 cells) of viable Arthrobacter, S. aureus, and E.coli after 3 hours of contact time and maintained their activity over 24 hours versus the control (untreated) samples.