Detection of adeno- and lentiviral (HIV1) contaminations on laboratory surfaces as a tool for the surveillance of biosafety standards.

AIMS: As a biosafety laboratory, we survey the handling of adenovirus type 5 (Ad5) and HIV1-derived lentivirus in contained-use facilities in Switzerland to identify insufficiencies of the safety precautions taken by the laboratories. METHODS AND RESULTS: In the past 9 years, we took 430 swab samples from various types of surfaces in research laboratories. Samples were examined for Ad5 contaminations by real-time PCR and infectivity assay or for the presence of lentivirus (HIV1) nucleic acids by real-time (RT) PCR. Samples collected from centrifuges did not only contain Ad5 DNA more frequently but also exhibited higher numbers of Ad5 and lentiviral (HIV1) DNA copies than swabs from any other area of sampling. Five of ten samples containing infectious Ad5 particles or lentivirus (HIV1) RNA were found in samples taken from centrifuges. Ad5 contamination rates were higher in the tube holder and lower on the inner wall of the rotor chamber in centrifuges that were fitted with aerosol tight covers compared to centrifuges without covers. CONCLUSIONS: Our results allowed the comparison of hygiene standards of different laboratories and lead to the identification of centrifuges as hotspots for contaminations. SIGNIFICANCE AND IMPACT OF THE STUDY: Based on our results, we propose to use the collected data as a tool for rating future swab results. Furthermore, the amount of Ad5 and HIV1-derived lentivirus DNA could serve as an indicator of the level of good laboratory practice in contained-use laboratories handling these viral vectors.

Contaminations of laboratory surfaces with Staphylococcus aureus are affected by the carrier status of laboratory staff.

AIM: As a biosafety laboratory, we take samples from surfaces in microbiological laboratories to survey the handling of micro-organisms. Whereas contaminations with other micro-organisms were rare, Staphylococcus aureus was found in the working environment of many laboratories. As 20-60% of the healthy population are carriers of S. aureus we wanted to asses the effect of carriers on our sampling results. METHODS AND RESULTS: Nasal swabs of staff members in nonmicrobiological laboratories and offices as well as surface samples from their personal work environment were taken and analysed for S. aureus DNA. In addition S. aureus strains were isolated using S. aureus-specific agar plates and analysed by randomly amplified polymorphic DNA (RAPD)-PCR and multilocus sequence typing (MLST). Our data show that contaminations with S. aureus in nonmicrobiological environments are common with 29% of the surface samples containing S. aureus DNA. In the working environment of carriers, the number of contaminations was significantly increased compared to the environment of noncarriers. CONCLUSION: The carrier status of staff members significantly affects the number of contaminations on laboratory surfaces. Therefore, even in the absence of intentional handling of S. aureus, contaminations can be detected on a substantial amount of surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: Sampling procedures need to be adapted based on these results with respect to the locations where samples are taken and the threshold for significant contaminations. Because of its wide distribution, S. aureus can serve as a marker for hygienic standards in laboratories.