Publications

Fungicidal efficacy of alcoholic disinfectants

M. Sc. Christin Becker and Dr. rer. nat. Steffen Salzmann, Schülke&Mayr
Lisa Struve, bactologicum
Dr. rer. nat. Dustin Kurka
Dr. rer. nat. Daniela Prasse
Dr. rer. nat. Lars Paßvogeland
Dr. rer. nat. Esther Steigleder, Schülke&Mayr
Prof. Dr. rer. nat. Katrin Steinhauer bactologicum and Kiel University of Applied Sciences

Abstract

To be used as disinfectants in Europe, biocidal products such as alcoholic disinfectants are regulated by the EU’s Biocidal Product Regulation (BPR) EU No. 528/2012. Due to varying lengths of authorization procedures under the BPR, EN (European Norm) methods may change during the evaluation of BPR product authorizations, which may result in different antimicrobial efficacy claims for identical formulations such as 70 % (v/v) propan-2-ol. In this study, we investigated the impact of cultivation of A. brasiliensis established in EN 1650 in 2013 compared to the previous version of EN 1650 on fungicidal efficacy against A. brasiliensis. For this, 70 % (v/v) propan-2-ol and 80 % (v/v) ethanol were used as test formulations. Direct comparison of efficacy data based on differing protocols given in different versions of EN 1650, revealed significant differences for efficacy of 70 % (v/v) propan-2-ol against A. brasiliensis, whereas no significant difference was found for 80 % (v/v) ethanol.

Evaluation of 15-second alcohol-based hand rub efficacy: a multi-laboratory study using a modified EN 1500 protocol

K-M. Roesch^a,b ∙ J. Gebel^a,b ∙ A. Bolten^c ∙ M. Cavalleri^d ∙ B. Christiansenb ∙ F. Droopa ∙ B. Eiltse ∙ M. Exnerb,f ∙ H. Gabrielg ∙ C. Hildebrandt^h ∙ T. Koburger-Janssenⁱ ∙ K. Konrat^j ∙ C.S. Lee^k ∙ J. Lenz^l ∙ H. Martiny^b ∙ M. Meckel^m ∙ N.T. Mutters^a ∙ S. Pahlⁿ ∙ L. Paßvogel^o ∙ C. Schartner^p ∙ F. Seyringer^q ∙ K. Steinhauer^r ∙ L.J. Vecchio^s ∙ L. Vossebein^b,t ∙ A. Wille^u ∙ A. Kramer^b,v,1 ∙ M. Suchomel^b,w,1

Affiliations & Notes

^aInstitute for Hygiene and Public Health, University Hospital Bonn, Bonn, Germany ^bAssociation for Applied Hygiene, Bonn, Germany ^cBODE Chemie GmbH, Hamburg, Germany ^dEurofins Biolab Srl, Part of Eurofins Scientific Inc, Milan, Italy ^eHochschule Albstadt-Sigmaringen, Sigmaringen, Germany ^fUniversity Bonn, Bonn, Germany ^gDr. Brill + Partner GmbH, Hamburg, Germany ^hHygCen Germany GmbH, Schwerin, Germany ⁱHygiene Nord GmbH, Greifswald, Germany ^jRobert Koch-Institute, Hospital Hygiene, Infection Prevention and Control, Berlin, Germany ^kTecolab Sdn Bhd, Kuala Lumpur, Malaysia ^lChemische Fabrik Dr. Weigert GmbH & Co.KG, Hamburg, Germany ^miki - Institut für Krankenhaushygiene & Infektionskontrolle GmbH, Gießen, Germany ⁿEcolab Deutschland GmbH, Monheim, Germany ^oSchülke & Mayr GmbH, Norderstedt, Germany ^pW.H.U. GmbH, Bischofshofen, Austria ^qHydrologische Untersuchungsstelle Salzburg GmbH, Salzburg, Austria ^rbactologicum GmbH, Itzehoe, University of Applied Sciences Kiel, Kiel, Germany ^sChelab srl - Mérieux Nutrisciences, Italy ^tUniversity of Applied Science Niederrhein - Textile Technology, Textile Examinations and Quality Management, Mönchengladbach, Germany ^uInstitut für Hygiene und Umwelt, Freie Und Hansestadt Hamburg, Germany ^vInstitute of Hygiene and Environmental Medicine, University Medicine Greifswald, Germany ^wInstitute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria ¹These authors contributed equally.

Summary

Introduction

Hands are a key vector for pathogen transmission in healthcare, making effective hand antisepsis crucial for infection prevention. According to the European standard EN 1500, the reference method for evaluating hand antiseptics, a minimum rub-in time of 30 s is required. However, observations show healthcare workers typically spend less time on hand antisepsis.

Method

To assess the feasibility of a reduced rub-in time under standardized conditions, the German Association for Applied Hygiene conducted a multi-centre ring trial in 14 laboratories using a modified EN 1500 protocol (15 s, 3 mL of 60% v/v propan-2-ol). In a randomized crossover design, volunteers’ hands were contaminated with Escherichia coli K12 and treated either with the reference (2 × 3 mL/2 × 30 s) or the test protocol (1 x 3 mL/15 s). Microbial reduction was measured and non-inferiority statistically analysed.

Results

The 15-second protocol yielded significantly lower log10 reductions than the reference in 13 out of 14 laboratories but demonstrated consistent reproducibility and satisfactory interlaboratory performance. Challenges in completing the full rub-in technique within 15 s were reported, indicating the need for targeted training.

Conclusion

These findings support the methodological feasibility of a shortened protocol and are consistent with evolving clinical guidelines advocating reduced rub-in times, as well as with real-world practice, where healthcare workers typically spend less than 30 s on hand antisepsis. Nonetheless, any revision of EN 1500 should proceed cautiously to ensure antimicrobial efficacy, emphasizing complete hand coverage and strict adherence to technique.

Enhancing the validity of virucidal activity testing of chemical disinfectants by establishing new reference substances according to EN 14476:2019

Correspondence: Kira-Marie Roesch^1,2
Claudia Hildebrandt ³
Maren Eggers ^1,4
Florian Brill ⁵
Michele Cavalleri ⁶
Jürgen Gebel ^1,2
Birgit Hunsinger ⁷
Sophie Loeffert ⁸
Marvin Rausch ^1,2
Ingeborg Schwebke ^1,9,10
Katrin Steinhauer ¹¹
Martin Exner ¹
Nico T. Mutters ²

¹Association for Applied Hygiene (VAH), Bonn, Germany
²Institute for Hygiene and Public Health. University Hospital Bonn, Bonn, Germany
³HygCen Germany GmbH, Schwerin, Germany
⁴Labor Prof. Dr. G. Enders MVZ GbR, Stuttgart, Germany
⁵Dr. Brill + Partner GmbH, Hamburg, Germany
⁶Eurofins Biolab Srl, Vimodrone, Italy
⁷Laboklin Labor für Klinische Diagnostik GmbH & Co. KG, Bad Kissingen, Germany
⁸Laboratoires Anios – an Ecolab company, Sainghin-en-Mélantois, France
⁹Expert Committee on Virus Disinfection of the German Association for the Control of Viral Diseases (DVV) e. V. and the Society for Virology (GfV) e.V., Heidelberg, Germany
¹⁰University Medicine Greifswald, Institute for Hygiene and Environmental Medicine, Greifswald, Germany
¹¹Bactologicum GmbH, Itzehoe, Germany

Abstract

Introduction: Reference tests are crucial for ensuring the comparability and quality assurance of test results in the field of chemical disinfectant testing. For testing virucidal activity, EN 14476:2019 specifies formaldehyde as reference substance. However, due to toxicological and technical concerns, formaldehyde needs to be replaced with new and more suitable reference substances.

In order to find the replacement, in 2023-24 an international ring trial was conducted by the European Standardization Committee TC 216 WG 1 (chemical disinfectants and antiseptics, working group human medicine) with 17 participating laboratories. The goal was to evaluate the suitability of these substances for optimization of existing standards.

Materials and methods: The study assessed the stability of the test viruses used in the disinfection test – specifically, Modified vaccinia virus Ankara, Adenovirus type 5, Murine Norovirus S99, Minute Virus of Mice, Poliovirus type 1 strain LSc-2ab and Bovine Enterovirus type 1 – to two newly selected reference substances: glutaraldehyde and peracetic acid.

The study tested reproducibility and repeatability based on a predefined test protocol.

Results: The results of the two tested reference substances – glutaraldehyde and peracetic acid – provide new reference substance ranges for relevant test viruses. The findings are incorporated into the revision of the European standards, ensuring the quality assurance of efficacy testing in virucidal testing.

Die Grenzen des Wachstums

Autoren:

Prof. Dr. Katrin Steinhauer, bactologicum GmbH; University of Applied Sciences Kiel; VAAM-Fachgruppe Qualitätsmanagement

Dr. Frank Mertens, VAAM-Fachgruppe Qualitätsmanagement

Korrespondenz:

Frank Mertens | Wacholderhain 10, 48369 Saerbeck | qm@vaam.de

Zusammenfassung
„Mikrobiologie ist eine logarithmische Wissenschaft“. Diese klare Aussage aus der USP weist darauf hin, dass mikrobiologische Prüfungen und Prüfergebnisse deutlich variabler sind als chemische und physikalische Prüfungen. Diese Eigenheiten führen häufig zu Unverständnis bei Chemikern und Pharmazeuten gegenüber Mikrobiologen. In dieser Arbeit soll eine Übersicht zu den mikrobiologischen Ursachen dieser Variabilität gegeben werden und wie diese in den Regelwerken abge- bildet sind. Darauf aufbauend werden etablierte mikrobiologische Limits kritisch betrachtet. Alternative mikrobiologische Methoden sowie qualitative Verfahren zur Identifizierung detektierter Mikroorganismen können kultur-basierte Methoden sinnvoll ergänzen. Dabei sind kritische Beurteilungen der quantitativen und qualitativen Ergebnisse durch erfahrene Experten in der Mikrobiologie unersetzlich.

Validation of Disinfectants in Pharmaceutics based on European Standard Test Methods

Prof. Dr. Katrin Steinhauer^1,2,
Dr. Maren Grütters³

¹bactologicum GmbH, Itzehoe, Germany

²Faculty of Mechanical Engineering, Kiel University of Applied Sciences, Kiel, Germany

³Schülke & Mayr GmbH, Norderstedt, Germany

Abstract
In the production area, especially in areas for the manufacture of pharmaceuticals, it is the task of the companies manufacturing according to GMP to iden- tify contamination risks in the course of production and to implement an effective contamination control strategy (CCS). In this context, cleaning and disinfection processes play a role in addition to the consideration of the manu- facturing process, the spatial conditions, the personnel, and the associated personnel hygiene. In this context, European Norm (EN) methods for determining the effectiveness of disinfectants can be adapted for the validation of disinfectants in the GMP environment. In this way, the required proof of the efficacy of the disinfectants used on the in-house specific surfaces can be demonstrated in a systematic, application-related, and needs-based manner. This includes both the surfaces available on site and the in-house flora, i.e., the specific microorganisms detected at the production site.

Benefits and Limitations of Species Identification

Dr. Frank Mertens^a,
Prof. Dr. Katrin Steinhauer^b,c,

^aVAAM-Fachgruppe Qualitätsmanagement

^bbactologicum GmbH, Itzehoe, Germany

^cFaculty of Mechanical Engineering, University of Applied Sciences, Kiel, Germany

Abstract
Microbial contaminants can have a huge impact on product safety. Thus, microbiological testing is required for many products and production processes. Good production hygiene is of the utmost importance for contamination control of pharmaceutical manufacturing processes for sterile and non-sterile drugs. In Chapter 5.1.4 the European Pharmacopeia suggests microbiological limits for final products. However, for environmental monitoring there are no detailed requirements for specific organisms. The question arises, to what level an isolate from the manufacturing environment should be identified. How beneficial is species identification? Is it always necessary to have a name for an isolated contaminant in production processes? This article discusses the need for identification of microbial contaminants in pharmaceutical production environments, especially in the light of the information required to establish an appropriate disinfection regime. In the context of contamination control and production hygiene measures, the need for unconditional identification using high-tech methods is reflected.

Efficacy of octenidine- and chlorhexidine-based wash-mitts against Candida albicans and Candida auris – a comparative study

F. Gugsch^a, C.K. Tan^a, D.Y. Oh^b, L. Paßvogel^b, K. Steinhauer<sup>ac

a</sup>bactologicum GmbH, Itzehoe, Germany
^bSchülke & Mayr GmbH, Norderstedt, Germany
^cUniversity of Applied Sciences, Kiel, Germany

Summary

Background

Management of outbreaks of the newly emerging pathogen Candida auris may include use of antimicrobial wash-mitts for decolonization. However, currently there is little clinical evidence to support the wide adoption of ‘whole-body decolonization’ as part of the protocol to effectively manage C. auris outbreaks. The aim of this study was to investigate the chemical tolerance of C. auris compared with the surrogate test organism Candida albicans as established in the European Standards (EN).

Methods

Two commercially available antiseptic-impregnated wash-mitts based on either chlorhexidine digluconate (CHG) or octenidine dihydrochloride (OCT) were studied. Comparison of susceptibility of C. auris and C. albicans was investigated based on the standardized test protocol EN 13624. Experiments were conducted using the impregnation liquid squeezed from the wash-mitts at a contact time of 30 s at different concentrations between 0.5% and 97% in the presence of low organic soiling.

Findings

Yeasticidal efficacy according to EN 13624 was found for the OCT wash-mitts at 30 s at ≥10% concentration with C. albicans. In comparison, reduction ≥4 log₁₀ was found at a much lower concentration of ≥1% for both C. auris strains. For the CHG wash-mitts, efficacy against C. albicans was below 2 log₁₀ reduction at 97% concentration within 30 s. Efficacy against the two C. auris strains was around 3 log₁₀ reduction.

Conclusion

Both C. auris strains were found to be significantly more susceptible when compared with C. albicans. Data also demonstrate that not all antiseptic-impregnated wash-mitts are equally effective against C. auris with OCT having a higher efficacy compared with CHG.

Long-Term Biocide Efficacy and Its Effect on a Souring Microbial Community.

Shi X, Oliveira DAF, Holsten L, Steinhauer K, de Rezende JR.

Appl Environ Microbiol. 2021 Aug 11;87(17):e0084221. doi: 10.1128/AEM.00842-21. Epub 2021 Aug 11.

PMID: 34160245
Free PMC article.

Abstract
Reservoir souring, which is the production of H2S mainly by sulfate-reducing microorganisms (SRM) in oil reservoirs, has been a long-standing issue for the oil industry. While biocides have been frequently applied to control biogenic souring, the effects of biocide treatment are usually temporary, and biocides eventually fail. The reasons for biocide failure and the long-term response of the microbial community remain poorly understood. In this study, one-time biocide treatments with glutaraldehyde (GA) and an aldehyde-releasing biocide (ARB) at low (100 ppm) and high (750 ppm) doses were individually applied to a complex SRM community, followed by 1 year of monitoring of the chemical responses and the microbial community succession. The chemical results showed that souring control failed after 7 days at a dose of 100 ppm regardless of the biocide type and lasting souring control for the entire 1-year period was achieved only with ARB at 750 ppm. Microbial community analyses suggested that the high-dose biocide treatments resulted in 1 order of magnitude lower average total microbial abundance and average SRM abundance, compared to the low-dose treatments. The recurrence of souring was associated with reduction of alpha diversity and with long-term microbial community structure changes; therefore, monitoring changes in microbial community metrics may provide early warnings of the failure of a biocide-based souring control program in the field. Furthermore, spore-forming sulfate reducers (Desulfotomaculum and Desulfurispora) were enriched and became dominant in both GA-treated groups, which could cause challenges for the design of long-lasting remedial souring control strategies. IMPORTANCE Reservoir souring is a problem for the oil and gas industry, because H2S corrodes the steel infrastructure, downgrades oil quality, and poses substantial risks to field personnel and the environment. Biocides have been widely applied to remedy souring, but the long-term performance of biocide treatments is hard to predict or to optimize due to limited understanding of the microbial ecology affected by biocide treatment. This study investigates the long-term biocide performance and associated changes in the abundance, diversity, and structure of the souring microbial community, thus advancing the knowledge toward a deeper understanding of the microbial ecology of biocide-treated systems and contributing to the improvement of current biocide-based souring control practices. The study showcases the potential application of incorporating microbial community analyses to forecast souring, and it highlights the long-term consequences of biocide treatment in the microbial communities, with relevance to both operators and regulators.

Virucidal efficacy of different formulations for hand and surface disinfection targeting SARS CoV-2

Steinhauer K, Meister TL, Todt D, Krawczyk A, Paßvogel L, Becker B, Paulmann D, Bischoff B, Eggers M, Pfaender S, Brill FHH, Steinmann E. J Hosp Infect. 2021 Jun;112:27-30. doi: 10.1016/j.jhin.2021.03.015. Epub 2021 Mar 23.
PMID: 33771601
Free PMC article.

Abstract
In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming 'virucidal activity against enveloped viruses' as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming 'virucidal activity against enveloped viruses' based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Improved method for tuberculocidal and mycobactericidal activity testing of disinfectants based on the European Standard EN 14348

Brill FHH, Lenz J, Lach C, Radischat N, Paßvogel L, Goroncy-Bermes P, Gabriel H, Steinmann J, Steinhauer K. J Hosp Infect. 2021 May;111:176-179. doi: 10.1016/j.jhin.2021.02.008. Epub 2021 Feb 11.
PMID: 33582203

Abstract
Safe measurements to prevent the transmission of (multidrug-resistant) mycobacteria such as disinfection are essential in healthcare settings. In Europe chemical disinfectants are tested for their tuberculocidal and mycobactericidal efficacy by the internationally accepted test procedure described in EN 14348. However, especially for amine-based disinfectants, invalid results may occur by this procedure due to insufficient neutralization. In this multi-laboratory study the procedure described in EN 14348 was optimized by a combination of chemical neutralization and membrane filtration in order to obtain a valid and secure method especially for amine-based disinfectants.

Comparison of the in-vitro efficacy of different mouthwash solutions targeting SARS-CoV-2 based on the European Standard EN 14476.

Steinhauer K, Meister TL, Todt D, Krawczyk A, Paßvogel L, Becker B, Paulmann D, Bischoff B, Pfaender S, Brill FHH, Steinmann E. J Hosp Infect. 2021 May;111:180-183. doi: 10.1016/j.jhin.2021.01.031. Epub 2021 Feb 11.
PMID: 33582201
Free PMC article.

Abstract
The outbreak of the SARS-CoV-2 pandemic is triggering a global health emergency alert. Until vaccination becomes available, a bundle of effective preventive measures is desperately needed. Recent research is indicating the relevance of aerosols in the spread of SARS-CoV-2. Thus, in this study commercially available antiseptic mouthwashes based on the active ingredients chlorhexidine digluconate and octenidine dihydrochloride (OCT) were investigated regarding their efficacy against SARS-CoV-2 using the European Standard 14476. Based on the requirement of EN 14476 in which reduction of at least four decimal logarithms (≥4 log10) of viral titre is requested to state efficacy, the OCT-based formulation was found to be effective within a contact time of only 15 s against SARS-CoV-2. Based on this in-vitro data the OCT mouthwash thus constitutes an interesting candidate for future clinical studies to prove its effectiveness in a potential prevention of SARS-CoV-2 transmission by aerosols.

The European tiered approach for virucidal efficacy testing - rationale for rapidly selecting disinfectants against emerging and re-emerging viral diseases.

Eggers M, Schwebke I, Suchomel M, Fotheringham V, Gebel J, Meyer B, Morace G, Roedger HJ, Roques C, Visa P, Steinhauer K. Euro Surveill. 2021 Jan;26(3):2000708. doi: 10.2807/1560-7917.ES.2021.26.3.2000708.
PMID: 33478622
Free PMC article.

Abstract
When facing an emerging virus outbreak such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a quick reaction time is key to control the spread. It takes time to develop antivirals and vaccines, and implement vaccination campaigns. Therefore, preventive measures such as rapid isolation of cases and identification and early quarantine of cases' close contacts-as well as masks, physical distancing, hand hygiene, surface disinfection and air control-are crucial to reduce the risk of transmission. In this context, disinfectants and antiseptics with proven efficacy against the outbreak virus should be used. However, biocidal formulations are quite complex and may include auxiliary substances such as surfactants or emollients in addition to active substances. In order to evaluate disinfectants' efficacy objectively, meaningful efficacy data are needed. Therefore, the European Committee for Standardisation technical committee 216 'Chemical disinfectants and antiseptics' Working Group 1 (medical area) has developed standards for efficacy testing. The European tiered approach grades the virucidal efficacy in three levels, with corresponding marker test viruses. In the case of SARS-CoV-2, disinfectants with proven activity against vaccinia virus, the marker virus for the European claim 'active against enveloped viruses', should be used to ensure effective hygiene procedures to control the pandemic.

Chemical disinfection in healthcare settings: critical aspects for the development of global strategies

Exner M, Bhattacharya S, Gebel J, Goroncy-Bermes P, Hartemann P, Heeg P, Ilschner C, Kramer A, Ling ML, Merkens W, Oltmanns P, Pitten F, Rotter M, Schmithausen RM, Sonntag HG, Steinhauer K, Trautmann M. GMS Hyg Infect Control. 2020 Dec 23;15:Doc36. doi: 10.3205/dgkh000371. eCollection 2020.
PMID: 33520601
Free PMC article.

Abstract Chemical disinfection is an indispensable means of preventing infection. This holds true for healthcare settings, but also for all other settings where transmission of pathogens poses a potential health risk to humans and/or animals. Research on how to ensure effectiveness of disinfectants and the process of disinfection, as well as on when, how and where to implement disinfection precautions is an ongoing challenge requiring an interdisciplinary team effort. The valuable resources of active substances used for disinfection must be used wisely and their interaction with the target organisms and the environment should be evaluated and monitored closely, if we are to reliable reap the benefits of disinfection in future generations. In view of the global threat of communicable diseases and emerging and re-emerging pathogens and multidrug-resistant pathogens, the relevance of chemical disinfection is continually increasing. Although this consensus paper pinpoints crucial aspects for strategies of chemical disinfection in terms of the properties of disinfectant agents and disinfection practices in a particularly vulnerable group and setting, i.e., patients in healthcare settings, it takes a comprehensive, holistic approach to do justice to the complexity of the topic of disinfection.

Efficacy of octenidine- and chlorhexidine-based wash-mitts against Candida albicans and Candida auris – a comparative study

F. Gugsch^a, C.K. Tan^a, D.Y. Oh^b, L. Paßvogel^b, K. Steinhauer<sup>ac

a</sup>bactologicum GmbH, Itzehoe, Germany
^bSchülke & Mayr GmbH, Norderstedt, Germany
^cUniversity of Applied Sciences, Kiel, Germany

Summary

Background

Management of outbreaks of the newly emerging pathogen Candida auris may include use of antimicrobial wash-mitts for decolonization. However, currently there is little clinical evidence to support the wide adoption of ‘whole-body decolonization’ as part of the protocol to effectively manage C. auris outbreaks. The aim of this study was to investigate the chemical tolerance of C. auris compared with the surrogate test organism Candida albicans as established in the European Standards (EN).

Methods

Two commercially available antiseptic-impregnated wash-mitts based on either chlorhexidine digluconate (CHG) or octenidine dihydrochloride (OCT) were studied. Comparison of susceptibility of C. auris and C. albicans was investigated based on the standardized test protocol EN 13624. Experiments were conducted using the impregnation liquid squeezed from the wash-mitts at a contact time of 30 s at different concentrations between 0.5% and 97% in the presence of low organic soiling.

Findings

Yeasticidal efficacy according to EN 13624 was found for the OCT wash-mitts at 30 s at ≥10% concentration with C. albicans. In comparison, reduction ≥4 log₁₀ was found at a much lower concentration of ≥1% for both C. auris strains. For the CHG wash-mitts, efficacy against C. albicans was below 2 log₁₀ reduction at 97% concentration within 30 s. Efficacy against the two C. auris strains was around 3 log₁₀ reduction.

Conclusion

Both C. auris strains were found to be significantly more susceptible when compared with C. albicans. Data also demonstrate that not all antiseptic-impregnated wash-mitts are equally effective against C. auris with OCT having a higher efficacy compared with CHG.

Long-Term Biocide Efficacy and Its Effect on a Souring Microbial Community.

Shi X, Oliveira DAF, Holsten L, Steinhauer K, de Rezende JR.

Appl Environ Microbiol. 2021 Aug 11;87(17):e0084221. doi: 10.1128/AEM.00842-21. Epub 2021 Aug 11.

PMID: 34160245
Free PMC article.

Abstract
Reservoir souring, which is the production of H2S mainly by sulfate-reducing microorganisms (SRM) in oil reservoirs, has been a long-standing issue for the oil industry. While biocides have been frequently applied to control biogenic souring, the effects of biocide treatment are usually temporary, and biocides eventually fail. The reasons for biocide failure and the long-term response of the microbial community remain poorly understood. In this study, one-time biocide treatments with glutaraldehyde (GA) and an aldehyde-releasing biocide (ARB) at low (100 ppm) and high (750 ppm) doses were individually applied to a complex SRM community, followed by 1 year of monitoring of the chemical responses and the microbial community succession. The chemical results showed that souring control failed after 7 days at a dose of 100 ppm regardless of the biocide type and lasting souring control for the entire 1-year period was achieved only with ARB at 750 ppm. Microbial community analyses suggested that the high-dose biocide treatments resulted in 1 order of magnitude lower average total microbial abundance and average SRM abundance, compared to the low-dose treatments. The recurrence of souring was associated with reduction of alpha diversity and with long-term microbial community structure changes; therefore, monitoring changes in microbial community metrics may provide early warnings of the failure of a biocide-based souring control program in the field. Furthermore, spore-forming sulfate reducers (Desulfotomaculum and Desulfurispora) were enriched and became dominant in both GA-treated groups, which could cause challenges for the design of long-lasting remedial souring control strategies. IMPORTANCE Reservoir souring is a problem for the oil and gas industry, because H2S corrodes the steel infrastructure, downgrades oil quality, and poses substantial risks to field personnel and the environment. Biocides have been widely applied to remedy souring, but the long-term performance of biocide treatments is hard to predict or to optimize due to limited understanding of the microbial ecology affected by biocide treatment. This study investigates the long-term biocide performance and associated changes in the abundance, diversity, and structure of the souring microbial community, thus advancing the knowledge toward a deeper understanding of the microbial ecology of biocide-treated systems and contributing to the improvement of current biocide-based souring control practices. The study showcases the potential application of incorporating microbial community analyses to forecast souring, and it highlights the long-term consequences of biocide treatment in the microbial communities, with relevance to both operators and regulators.

Virucidal efficacy of different formulations for hand and surface disinfection targeting SARS CoV-2

Steinhauer K, Meister TL, Todt D, Krawczyk A, Paßvogel L, Becker B, Paulmann D, Bischoff B, Eggers M, Pfaender S, Brill FHH, Steinmann E. J Hosp Infect. 2021 Jun;112:27-30. doi: 10.1016/j.jhin.2021.03.015. Epub 2021 Mar 23.
PMID: 33771601
Free PMC article.

Abstract
In the ongoing SARS CoV-2 pandemic, effective disinfection measures are needed, and guidance based on the methodological framework of the European Committee for Standardization (CEN) may enable the choice of effective disinfectants on an immediate basis. This study aimed to elucidate whether disinfectants claiming 'virucidal activity against enveloped viruses' as specified in the European Standard EN 14476 as well as in the German Association for the Control of Viral Diseases/Robert Koch Institute (DVV/RKI) guideline are effectively inactivating SARS-CoV-2. Two commercially available formulations for surface disinfection and one formulation for hand disinfection were studied regarding their virucidal activity. Based on the data of this study the enveloped SARS-CoV-2 is at least equally susceptible compared to the standard test virus vaccinia used in the EN 14476 and DVV/RKI guidelines. Thus, chemical disinfectants claiming 'virucidal activity against enveloped viruses' based on the EN 14476 and DVV/RKI guidelines will be an effective choice to target enveloped SARS-CoV-2 as a preventive measure.

Improved method for tuberculocidal and mycobactericidal activity testing of disinfectants based on the European Standard EN 14348

Brill FHH, Lenz J, Lach C, Radischat N, Paßvogel L, Goroncy-Bermes P, Gabriel H, Steinmann J, Steinhauer K. J Hosp Infect. 2021 May;111:176-179. doi: 10.1016/j.jhin.2021.02.008. Epub 2021 Feb 11.
PMID: 33582203

Abstract
Safe measurements to prevent the transmission of (multidrug-resistant) mycobacteria such as disinfection are essential in healthcare settings. In Europe chemical disinfectants are tested for their tuberculocidal and mycobactericidal efficacy by the internationally accepted test procedure described in EN 14348. However, especially for amine-based disinfectants, invalid results may occur by this procedure due to insufficient neutralization. In this multi-laboratory study the procedure described in EN 14348 was optimized by a combination of chemical neutralization and membrane filtration in order to obtain a valid and secure method especially for amine-based disinfectants.

Comparison of the in-vitro efficacy of different mouthwash solutions targeting SARS-CoV-2 based on the European Standard EN 14476.

Steinhauer K, Meister TL, Todt D, Krawczyk A, Paßvogel L, Becker B, Paulmann D, Bischoff B, Pfaender S, Brill FHH, Steinmann E. J Hosp Infect. 2021 May;111:180-183. doi: 10.1016/j.jhin.2021.01.031. Epub 2021 Feb 11.
PMID: 33582201
Free PMC article.

Abstract
The outbreak of the SARS-CoV-2 pandemic is triggering a global health emergency alert. Until vaccination becomes available, a bundle of effective preventive measures is desperately needed. Recent research is indicating the relevance of aerosols in the spread of SARS-CoV-2. Thus, in this study commercially available antiseptic mouthwashes based on the active ingredients chlorhexidine digluconate and octenidine dihydrochloride (OCT) were investigated regarding their efficacy against SARS-CoV-2 using the European Standard 14476. Based on the requirement of EN 14476 in which reduction of at least four decimal logarithms (≥4 log10) of viral titre is requested to state efficacy, the OCT-based formulation was found to be effective within a contact time of only 15 s against SARS-CoV-2. Based on this in-vitro data the OCT mouthwash thus constitutes an interesting candidate for future clinical studies to prove its effectiveness in a potential prevention of SARS-CoV-2 transmission by aerosols.

The European tiered approach for virucidal efficacy testing - rationale for rapidly selecting disinfectants against emerging and re-emerging viral diseases.

Eggers M, Schwebke I, Suchomel M, Fotheringham V, Gebel J, Meyer B, Morace G, Roedger HJ, Roques C, Visa P, Steinhauer K. Euro Surveill. 2021 Jan;26(3):2000708. doi: 10.2807/1560-7917.ES.2021.26.3.2000708.
PMID: 33478622
Free PMC article.

Abstract
When facing an emerging virus outbreak such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a quick reaction time is key to control the spread. It takes time to develop antivirals and vaccines, and implement vaccination campaigns. Therefore, preventive measures such as rapid isolation of cases and identification and early quarantine of cases' close contacts-as well as masks, physical distancing, hand hygiene, surface disinfection and air control-are crucial to reduce the risk of transmission. In this context, disinfectants and antiseptics with proven efficacy against the outbreak virus should be used. However, biocidal formulations are quite complex and may include auxiliary substances such as surfactants or emollients in addition to active substances. In order to evaluate disinfectants' efficacy objectively, meaningful efficacy data are needed. Therefore, the European Committee for Standardisation technical committee 216 'Chemical disinfectants and antiseptics' Working Group 1 (medical area) has developed standards for efficacy testing. The European tiered approach grades the virucidal efficacy in three levels, with corresponding marker test viruses. In the case of SARS-CoV-2, disinfectants with proven activity against vaccinia virus, the marker virus for the European claim 'active against enveloped viruses', should be used to ensure effective hygiene procedures to control the pandemic.

Chemical disinfection in healthcare settings: critical aspects for the development of global strategies

Exner M, Bhattacharya S, Gebel J, Goroncy-Bermes P, Hartemann P, Heeg P, Ilschner C, Kramer A, Ling ML, Merkens W, Oltmanns P, Pitten F, Rotter M, Schmithausen RM, Sonntag HG, Steinhauer K, Trautmann M. GMS Hyg Infect Control. 2020 Dec 23;15:Doc36. doi: 10.3205/dgkh000371. eCollection 2020.
PMID: 33520601
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Abstract Chemical disinfection is an indispensable means of preventing infection. This holds true for healthcare settings, but also for all other settings where transmission of pathogens poses a potential health risk to humans and/or animals. Research on how to ensure effectiveness of disinfectants and the process of disinfection, as well as on when, how and where to implement disinfection precautions is an ongoing challenge requiring an interdisciplinary team effort. The valuable resources of active substances used for disinfection must be used wisely and their interaction with the target organisms and the environment should be evaluated and monitored closely, if we are to reliable reap the benefits of disinfection in future generations. In view of the global threat of communicable diseases and emerging and re-emerging pathogens and multidrug-resistant pathogens, the relevance of chemical disinfection is continually increasing. Although this consensus paper pinpoints crucial aspects for strategies of chemical disinfection in terms of the properties of disinfectant agents and disinfection practices in a particularly vulnerable group and setting, i.e., patients in healthcare settings, it takes a comprehensive, holistic approach to do justice to the complexity of the topic of disinfection.