Assessment of chemical disinfectants against human immunodeficiency virus: overcoming the problem of cytotoxicity and the evaluation of selected actives

Efficient inactivation of pseudotyped HIV-based lentiviral vectors and infectious HIV

Lentiviral vectors and lentiviruses are important tools for basic and applied biomedical research. Yet, biosafety regulations from legal authorities have to be fulfilled when transferring BSL-2 to -3 vectors/viruses to facilities with lower biosafety level. Here, we (re-)evaluated different chemical and thermal approaches to inactivate vesicular stomatitis virus G-protein (VSV-G) pseudotyped lentiviral vectors and either wildtype or VSV-G pseudotyped human immunodeficiency viruses (HIV). Aldehydes, detergents and alcohols were as effective as thermal inactivation procedures to efficiently inactivate purified lentiviral vectors and replication-competent HIV. In addition, no residual infectivity was detected when inactivating HIV-infected TZM-bl reporter cells with selected detergents and aldehydes. Thus, our established inactivation protocols can be used by other laboratories working with lentiviral vectors or infectious lentiviruses and provide a template for viruses with similar physicochemical properties.

[Clinical experience with the hygienic reprocessing of rigid endoscopes lacking a working channel with reference to practicability in clinical routine]

BACKGROUND

Contaminated medical products may be vectors for infections. A safe disinfection method for the optical instruments used by ENT specialists is undoubtedly needed. So far, a standard method that sufficiently covers the risk of infection for patients and medical staff alike, while serving the need of practicability in daily routine, has not been established.

PATIENTS AND METHODS

In the ENT departments of the Mannheim and Kaiserslautern hospitals, a study on the practicability of disinfection rigid optical instruments lacking working channels was conducted using cleaning and disinfection automats. A total of 735 patients were examined (Hopkins 30 degrees and 70 degrees) and the endoscopes subsequently sterilized using a cleaning and disinfection automat.

RESULTS

Each cleaning cycle took about 40 min. Examining 70-100 patients a day, a minimum of eight 70 degrees Hopkins endoscopes would be needed.

CONCLUSION

The sterilization of medical products such as endoscopes is the best practice, but certain hindrances, such as loss of time and costs involved, complicate its general application.

Antimicrobial activity of a new intact skin antisepsis formulation

Different antiseptic formulations have shown limitations when applied to disinfecting intact skin, notably short-term tolerability and/or efficacy. The purpose of this study was optimizing a new antiseptic formulation specifically targeted at intact skin disinfection and evaluating its in vitro microbicidal activity and in vivo efficacy.

METHODS

The biocidal properties of the antiseptic solution containing 0.5% chloramine-T diluted in 50% isopropyl alcohol (Cloral; Eurospital SpA Trieste, Italy) were measured in vitro versus gram-positive-, gram-negative-, and acid-alcohol-resistant germs and fungi with standard suspension tests in the presence of fetal bovine serum. Virus-inhibiting activity was evaluated in vitro against human cytomegalovirus, herpes simplex virus, poliovirus, hepatitis B virus, and hepatitis C virus. Tests used different methods for the different biologic and in vitro replication capacity of these human viruses. Lastly, Cloral tolerability and skin colonization retardation efficacy after disinfection were studied in vivo.

RESULTS

The antiseptic under review showed fast and sustained antimicrobial activity. The efficacy of Cloral against clinically important bacterial and viral pathogens and fungi was highlighted under the experimental conditions described in this article. Finally, microbial regrowth lag and no side effects were documented in vivo after disinfection of 11 volunteers.

CONCLUSIONS

A stable chloramine-T solution in isopropyl alcohol may be suggested for intact skin antisepsis.

Efficacy and kinetics of glycerol inactivation of HIV-1 in split skin grafts

Allogeneic split skin grafts are used widely in the treatment of burns. The relative simplicity of glycerol preservation of skin suggests it will be used increasingly in areas of high HIV-1 seroprevalence. The ability of glycerol preservation to inactivate HIV-1 present in skin graft infected in vitro was determined using a macrophage tropic strain HIV-1 as a cell-free virus suspension, within infected PBMCs, or within in vitro HIV-1 infected fresh cadaveric split skin. Different temperatures and concentrations of glycerol were used and infectivity determined by coculture with mitogen activated peripheral blood mononuclear cells (PBMCs) and measurement of reverse transcriptase activity after 7-10 days. Cell-free HIV-1 was inactivated within 30 min at 4 degrees C in glycerol concentrations of 70% or higher. During similar exposure cell- or skin-associated HIV-1 titer was reduced but not eliminated with 70% and 85% glycerol at 4 degrees C. HIV-1 was recovered consistently from skin stored in 85% glycerol at 4 degrees C for up to 72 hr but virus isolation was infrequent after storage for more than 5 days. At 20 degrees C or 37 degrees C, 70% or 85% glycerol could inactivate cell- or skin-associated HIV-1 within 8 hr. The initial glycerolization procedures and the storage at 4 degrees C eliminated effectively HIV-1 from skin.