Mardjan Arvand

Background: In 2013, a global outbreak of Mycobacterium chimaera infections due to contaminated heater-cooler units emerged. This ongoing problem has highlighted the question of whether disinfection recommendations for medical devices containing water circuits are adequate for preventing contamination and possible recontamination by nontuberculous mycobacteria. The formation of biofilms in such devices exacerbates the problem. This study aimed to assess the efficacy of disinfectants on biofilms and suspensions of the M. chimaera strain ZUERICH-1, and to compare it with two unrelated M. chimaera strains obtained from different sources. Methods: Disinfection efficacy testing for biofilm was performed using a Bead Assay for Biofilms and for bacteria in suspension according to the European Standard EN 14348. Three different disinfectants, glutaraldehyde, sodium hypochlorite and peracetic acid, were assessed. M. chimaera ZUERICH-1, two genetically unrelated M. chimaera isolates and M. avium subsp. avium ATCC 15769, which is included in European standards for disinfectant testing on mycobacteria, were analyzed. The biofilms’ structure and composition were analyzed by chemical and molecular techniques and advanced imaging methods. Results: We found that peracetic acid and glutaraldehyde in standard concentrations were able to effectively inactivate (≥ 4 log ₁₀ reduction) suspended bacteria of all three strains, but chlorine failed in all cases. Formation of biofilm generally enhanced the tolerance of M. chimaera to disinfectants. Peracetic acid in standard concentration could not effectively inactivate biofilms of M. chimaera ZUERICH-1, but was effective against biofilms of the other M. chimaera strains tested. Similarly, glutaraldehyde in standard concentration could not inactivate biofilm of ZUERICH-1. Biomass analysis showed higher amounts of extracellular matrix of ZUERICH-1 when compared to the other two strains. Conclusions: The data suggest that current standard disinfection recommendations do not ensure sustained inhibition of M. chimaera when embedded in biofilm. Additional measures are needed to prevent nosocomial transmission of M. chimaera through contaminated heater-cooler units.

There is a growing interest in the implementation of people-centered components within outbreak preparedness and response plans and their resulting governance. Information on this topic still remains scarce, in particular in settings like Guinea, West Africa. We draw from 21 qualitative interviews with healthcare workers in the context of COVID-19 from the Faranah Regional Hospital in Guinea to explore pandemic preparedness and response adherence as well as its corresponding senses of vulnerability and risk, information sources, perceived information reliability, associated rumors and previous outbreak experiences. To achieve a broader analysis, we make use of the “therapeutic landscape” concept which conceives health provision as a process constructed through practices, beliefs and experiences. A theme articulated across interviews was an overabundance of information, which caused confusion mainly due to rumors and a lack of trust in the country’s health system. Initial fear gradually diminished due to the disease’s low mortality rate in the country. HCWs described preparedness enforcement in the city of Faranah that started strong but lightened overtime. This waning of enforcement marked a difference between the city and the hospital. HCWs appraised the first positive case declaration in the city as the most significant moment, followed by a strong community reaction hindering the pandemic governance. We conclude that preparedness and response plans need to better socially situate their interventions and devote more structural efforts into incorporating the social landscapes of a disease and an outbreak. Incorporation of these social landscapes facilitates understanding of operational barriers to their people-centered approaches. Responses should therefore comprehend 1) hospitals as applying different pandemic understandings transcending biomedical and scientific orders and 2) HCWs as portraying shifting pre-existing identities leading to marked in-/out-group distinctions directly influencing healthcare, risk perception as well as information and rumors management.

Background: Clostridioides difficile infections (CDI) present significant health risks and are among the most important nosocomial infections. Ribotype (RT) 027 poses a particular risk due to its proposed “hypervirulence”. Traditionally, C. difficile isolates are characterized using PCR-ribotyping. More recently, whole genome sequence (WGS) analysis is increasingly used, which may provide a higher discriminatory power. This study aimed to assess the distribution of different C. difficile RTs in hospitals in the Berlin-Brandenburg area, and to analyse the heterogeneity within isolates of different ribotypes using WGS. Methods: Between February 2020 and November 2021, stool samples from patients with laboratory-confirmed CDI were collected from 22 hospitals (approximately 13,900 beds) in Berlin and Brandenburg. Toxigenic isolates (n = 476) were further characterized by ribotyping, antibiotic susceptibility testing, toxinotyping, and core genome multilocus sequence typing (cgMLST). Results: Sixty-five different RTs were detected, with RT014 (16.1%), RT027 (12.8%), and RT001 (7.6%) being the most prevalent. RT027 isolates exhibited resistance to several antibiotics. Further, cgMLST analysis revealed very close genetic relatedness between RT027 isolates despite being epidemiologically unrelated. Similar findings of a monomorphic population were observed for RT078 isolates. In contrast, other RTs showed a heterogenic population structure. Conclusions: This study provides first insights into the distribution of C. difficile genotypes, corresponding antimicrobial resistance, and clonal relatedness using cgMLST, highlighting RT027 as the second most common genotype for the studied area. For the monomorphic RT027 and RT078 populations, new definitions of clonal relatedness might be necessary.

Zusammenfassung: Die Vermeidung der Weiterverbreitung der Erkrankung ist ein wesentliches Ziel in der Betreuung und Behandlung von Tuberkulose. Für die Infektionsprävention von besonderer Bedeutung sind neben der frühzeitigen Diagnose und effektiven Therapien eine Isolierung ansteckungsfähiger Patientinnen und Patienten und adäquate Hygienemaßnahmen. Die vorliegenden Empfehlungen ersetzen die bisherigen Empfehlungen „Infektionsprävention bei Tuberkulose“ aus dem Jahre 2012 und berücksichtigen die aktuellen nationalen und internationalen Empfehlungen und neue wissenschaftlichen Erkenntnisse. Nach einer Beschreibung der Infektion und der Übertragungswege werden die notwendigen Präventions- und Hygienemaßnahmen in Gesundheitseinrichtungen umfangreich dargestellt. Seit der letzten Überarbeitung der Empfehlungen zur Infektionsprävention wurden internationale Empfehlungen und die KRINKO-Empfehlung zur Beendigung der Isolierung geändert. In Übereinstimmung hiermit kann unter bestimmten Voraussetzungen bei sensibler Tuberkulose eine Entisolierung in Gesundheitseinrichtungen nach 14 Tagen ohne Berücksichtigung der Sputumbefunde erfolgen. Im zweiten Teil der Empfehlungen werden ausführlich die Maßnahmen in speziellen Situationen und Bereichen, wie Arztpraxen, Krankentransport und Pflegeeinrichtungen, erläutert. Hier wurden die Empfehlungen zum Atemschutz vereinfacht, für Personal wird eine FFP2-Maske nun generell als ausreichend erachtet.

Salmonella enterica is a causative pathogen of Salmonellosis, a zoonosis causing global disease and financial losses every year. Pigs may be carriers of Salmonella and contribute to the spread to humans and food products. Salmonella may persist as biofilms. Biofilms are bacterial aggregates embedded in a self-produced matrix and are known to withstand disinfectants. We studied the effect of glutaraldehyde and peracetic acid, two active substances frequently used in disinfectant formulations in the pig industry, on representative biofilm-residing wild-type Salmonella collected from pig housings in the United Kingdom (UK). We screened biofilm production of strains using the microtiter plate (MTP) assay and Congo Red Coomassie Blue (CRCB) agar method. Previously published stainless-steel coupon (SSCA), polyvinylchloride coupon (PCA), and glass bead (GBA) assays were used for disinfection studies. The mean reduction in the tested wild-type strains met the criterion of ≥4 log₁₀ CFU at a disinfectant concentration of 0.05% with SSCA and GBA, and 0.005% with PCA for peracetic acid, along with 0.5% for glutaraldehyde with all three assays on the mean. At these concentrations, both tested disinfectants are suitable for disinfection of pig housings against Salmonella. When evaluating the efficacy of disinfectants, biofilms should be included, as higher disinfectant concentrations are necessary compared to planktonic bacteria.

Within the European Union, Salmonella is frequently reported in food and feed products. A major route of transmission is upon contact with contaminated surfaces. In nature, bacteria such as Salmonella are often encountered in biofilms, where they are protected against antibiotics and disinfectants. Therefore, the removal and inactivation of biofilms is essential to ensure hygienic conditions. Currently, recommendations for disinfectant usage are based on results of efficacy testing against planktonic bacteria. There are no biofilm-specific standards for the efficacy testing of disinfectants against Salmonella. Here, we assessed three models for disinfectant efficacy testing on Salmonella Typhimurium biofilms. Achievable bacterial counts per biofilm, repeatability, and intra-laboratory reproducibility were analyzed. Biofilms of two Salmonella strains were grown on different surfaces and treated with glutaraldehyde or peracetic acid. Disinfectant efficacy was compared with results for planktonic Salmonella. All methods resulted in highly repeatable cell numbers per biofilm, with one assay showing variations of less than 1 log₁₀ CFU in all experiments for both strains tested. Disinfectant concentrations required to inactivate biofilms were higher compared to planktonic cells. Differences were found between the biofilm methods regarding maximal achievable cell numbers, repeatability, and intra-laboratory reproducibility of results, which may be used to identify the most appropriate method in relation to application context. Developing a standardized protocol for testing disinfectant efficacy on biofilms will help identify conditions that are effective against biofilms.

(1) Background: Clostridioides difficile infections (CDI) have increased worldwide, and the disease is one of the most common healthcare-associated infections (HAI). This study aimed to evaluate the molecular epidemiology of C. difficile, the clinical outcome, and the time of initiation of specific hygiene measures in patients with CDI in a large tertiary-care hospital in Brandenburg. (2) Methods: Faecal samples and data from hospitalised patients diagnosed with CDI were analysed from October 2016 to October 2017. The pathogens were isolated, identified as toxigenic C. difficile, and subsequently subtyped using PCR ribotyping and whole genome sequencing (WGS). Data regarding specific hygiene measures for handling CDI patients were collected. (3) Results: 92.1% of cases could be classified as healthcare-associated (HA)-CDI. The recurrence rate within 30 and 90 days after CDI diagnosis was 15.7% and 18.6%, and the mortality rate was 21.4% and 41.4%, respectively. The most frequent ribotypes (RT) were RT027 (31.3%), RT014 (18.2%), and RT005 (14.1%). Analysis of WGS data using cgMLST showed that all RT027 isolates were closely related; they were assigned to two subclusters. Single-room isolation or barrier measures were implemented in 95.7% patients. (4) Conclusions: These data show that RT027 is regionally predominant, thus highlighting the importance of specific hygiene measures to prevent and control CDI and the need to improve molecular surveillance of C. difficile at the local and national level.

Zusammenfassung: Hintergrund und Ziel: Die wichtige Rolle der Maßnahmen zur Infektionsprävention und -kontrolle in Langzeitpflegeeinrichtungen ist im Kontext der aktuellen SARS-CoV-2-Pandemie besonders deutlich geworden. Um eine verlässliche Datenbasis zu nosokomialen Infektionen und Antibiotikaanwendung zu gewinnen, hat das European Centre for Disease Prevention and Control (ECDC) 2016–2017 die dritte Punkt-Prävalenz-Erhebung in europäischen Langzeitpflegeeinrichtungen (HALT-3) initiiert. Material und Methoden: In Deutschland nahmen 131 Einrichtungen mit 10.565 Bewohnern teil. An einem Stichtag 2016 wurden die Anzahl von nosokomialen Infektionen, die Antibiotikaanwendung sowie Pflegecharakteristika und Risikofaktoren der Bewohner erhoben. Infektionen wurden symptombasiert anhand von Algorithmen entsprechend der McGeer-Surveillance-Definitionen für Pflegeeinrichtungen erfasst. Ergebnisse: Bei 177 Bewohnern wurde eine nosokomiale Infektion dokumentiert, was einer Prävalenz von 1,7 % (95 %-KI: 1,3–2,1) entspricht und im europäischen Vergleich (Mittelwert 3,9 %) ein eher niedriger Wert ist. Harnwegsinfektionen waren mit knapp 50 % die häufigsten Infektionen, gefolgt von Atemwegs‑, Haut- und Weichgewebeinfektionen. Die häufigsten Indikationen für eine Antibiotikaanwendung entsprechen den erfassten Infektionen. Bei 143 Bewohnern wurde eine Antibiotikaanwendung dokumentiert (Prävalenz 1,4 %, 95 %-KI: 1,1–1,7). Auffällig war der hohe Einsatz von Fluorchinolonen mit über 20 % aller Verordnungen. Diskussion: Der Aufbau einer einrichtungsbasierten Surveillance von nosokomialen Infektionen und Antibiotikaanwendung könnte zusammen mit der Zurverfügungstellung von spezifisch auf die geriatrische Population zugeschnittenen Leitlinien zur Verbesserung der Infektionsprävention und zum rationaleren Einsatz von Antibiotika beitragen sowie die Qualität und Sicherheit in der Pflege erhöhen.

Background: The approval of ethanol by the Biocidal Products Regulation has been under evaluation since 2007. This follows concern over alcohol uptake from ethanol-based hand rubs (EBHR). If ethanol is classified as carcinogenic, mutagenic, or reprotoxic by the European Chemicals Agency (ECHA), then this would affect infection prevention and control practices. Aim: A review was performed to prove that ethanol is toxicological uncritical and indispensable for hand antisepsis because of its unique activity against non-enveloped viruses and thus the resulting lack of alternatives. Therefore, the following main points are analyzed: The effectiveness of ethanol in hand hygiene, the evidence of ethanol at blood/tissue levels through hand hygiene in healthcare, and the evidence of toxicity of different blood/tissue ethanol levels and the non-comparability with alcoholic consumption and industrial exposure. Results: EBHR are essential for preventing infections caused by non-enveloped viruses, especially in healthcare, nursing homes, food industry and other areas. Propanols are effective against enveloped viruses as opposed to non-enveloped viruses but there are no other alternatives for virucidal hand antisepsis. Long-term ingestion of ethanol in the form of alcoholic beverages can cause tumours. However, lifetime exposure to ethanol from occupational exposure < 500 ppm does not significantly contribute to the cancer risk. Mutagenic effects were observed only at doses within the toxic range in animal studies. While reprotoxicity is linked with abuse of alcoholic beverages, there is no epidemiological evidence for this from EBHR use in healthcare facilities or from products containing ethanol in non-healthcare settings. Conclusion: The body of evidence shows EBHRs have strong efficacy in killing non-enveloped viruses, whereas 1-propanol and 2-propanol do not kill non-enveloped viruses, that pose significant risk of infection. Ethanol absorbed through the skin during hand hygiene is similar to consumption of beverages with hidden ethanol content (< 0.5% v/v), such as apple juice or kefir. There is no risk of carcinogenicity, mutagenicity or reprotoxicity from repeated use of EBHR. Hence, the WHO Task Force strongly recommend retaining ethanol as an essential constituent in hand rubs for healthcare.