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

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.

SARS-CoV-2 outbreak investigation in a German meat processing plant

We describe a multifactorial investigation of a SARS-CoV-2 outbreak in a large meat processing complex in Germany. Infection event timing, spatial, climate and ventilation conditions in the processing plant, sharing of living quarters and transport, and viral genome sequences were analyzed. Our results suggest that a single index case transmitted SARS-CoV-2 to co-workers over distances of more than 8 m, within a confined work area in which air is constantly recirculated and cooled. Viral genome sequencing shows that all cases share a set of mutations representing a novel sub-branch in the SARS-CoV-2 C20 clade. We identified the same set of mutations in samples collected in the time period between this initial infection cluster and a subsequent outbreak within the same factory, with the largest number of confirmed SARS-CoV-2 cases in a German meat processing facility reported so far. Our results indicate climate conditions, fresh air exchange rates, and airflow as factors that can promote efficient spread of SARS-CoV-2 via long distances and provide insights into possible requirements for pandemic mitigation strategies in industrial workplace settings.

SARS-CoV-2 outbreak investigation in a German meat processing plant

We describe a multifactorial investigation of a SARS-CoV-2 outbreak in a large meat processing complex in Germany. Infection event timing, spatial, climate and ventilation conditions in the processing plant, sharing of living quarters and transport, and viral genome sequences were analyzed. Our results suggest that a single index case transmitted SARS-CoV-2 to co-workers over distances of more than 8 m, within a confined work area in which air is constantly recirculated and cooled. Viral genome sequencing shows that all cases share a set of mutations representing a novel sub-branch in the SARS-CoV-2 C20 clade. We identified the same set of mutations in samples collected in the time period between this initial infection cluster and a subsequent outbreak within the same factory, with the largest number of confirmed SARS-CoV-2 cases in a German meat processing facility reported so far. Our results indicate climate conditions, fresh air exchange rates, and airflow as factors that can promote efficient spread of SARS-CoV-2 via long distances and provide insights into possible requirements for pandemic mitigation strategies in industrial workplace settings.

Bacteria isolated from hospital, municipal and slaughterhouse wastewaters show characteristic, different resistance profiles

Multidrug-resistant bacteria cause difficult-to-treat infections and pose a risk for modern medicine. Sources of multidrug-resistant bacteria include hospital, municipal and slaughterhouse wastewaters. In this study, bacteria with resistance to 3rd generation cephalosporins were isolated from all three wastewater biotopes, including a maximum care hospital, municipal wastewaters collected separately from a city and small rural towns and the wastewaters of two pig and two poultry slaughterhouses. The resistance profiles of all isolates against clinically relevant antibiotics (including β-lactams like carbapenems, the quinolone ciprofloxacin, colistin, and trimethoprim/sulfamethoxazole) were determined at the same laboratory. The bacteria were classified according to their risk to human health using clinical criteria, with an emphasis on producers of carbapenemases, since carbapenems are prescribed for hospitalized patients with infections with multi-drug resistant bacteria. The results showed that bacteria that pose the highest risk, i. e., bacteria resistant to all β-lactams including carbapenems and ciprofloxacin, were mainly disseminated by hospitals and were present only in low amounts in municipal wastewater. The isolates from hospital wastewater also showed the highest rates of resistance against antibiotics used for treatment of carbapenemase producers and some isolates were susceptible to only one antibiotic substance. In accordance with these results, qPCR of resistance genes showed that 90% of the daily load of carbapenemase genes entering the municipal wastewater treatment plant was supplied by the clinically influenced wastewater, which constituted approximately 6% of the wastewater at this sampling point. Likewise, the signature of the clinical wastewater was still visible in the resistance profiles of the bacteria isolated at the entry into the wastewater treatment plant. Carbapenemase producers were not detected in slaughterhouse wastewater, but strains harboring the colistin resistance gene mcr-1 could be isolated. Resistances against orally available antibiotics like ciprofloxacin and trimethoprim/sulfamethoxazole were widespread in strains from all three wastewaters.

Infection fatality rate of SARS-CoV2 in a super-spreading event in Germany

A SARS-CoV2 super-spreading event occurred during carnival in a small town in Germany. Due to the rapidly imposed lockdown and its relatively closed community, this town was seen as an ideal model to investigate the infection fatality rate (IFR). Here, a 7-day seroepidemiological observational study was performed to collect information and biomaterials from a random, household-based study population. The number of infections was determined by IgG analyses and PCR testing. We found that of the 919 individuals with evaluable infection status, 15.5% (95% CI:[12.3%; 19.0%]) were infected. This is a fivefold higher rate than the reported cases for this community (3.1%). 22.2% of all infected individuals were asymptomatic. The estimated IFR was 0.36% (95% CI:[0.29%; 0.45%]) for the community and 0.35% [0.28%; 0.45%] when age-standardized to the population of the community. Participation in carnival increased both infection rate (21.3% versus 9.5%, p < 0.001) and number of symptoms (estimated relative mean increase 1.6, p = 0.007). While the infection rate here is not representative for Germany, the IFR is useful to estimate the consequences of the pandemic in places with similar healthcare systems and population characteristics. Whether the super-spreading event not only increases the infection rate but also affects the IFR requires further investigation.

Measures to maintain regular operations and prevent outbreaks of SARS-CoV-2 in childcare facilities or schools under pandemic conditions and co-circulation of other respiratory pathogens

After the lockdown and the end of the summer holidays, day-cares and schools need to be reopened and (despite the continued circulation of the new coronavirus SARS-CoV-2) kept open. The need for opening up arises from the right of children to education, participation, support and care. This is possible if appropriate hygiene measures are implemented and community transmission remains stable. In addition, the safety of educators, teachers and carers must be a priority and needs to be addressed by appropriate measures. Finally, the needs of families must also be taken into account. The following document describes in detail how these objectives can be achieved.

Impact of surface disinfection with hydrogen peroxide on the prevalence of vancomycin-resistant enterococci (VRE) in hospital wards

Objective: Vancomycin-resistant enterococci (VRE) are of major concern in infection control. Although broad infection control actions to check VRE have been implemented, VRE remain part of daily infection prevention in clinical settings. Cleaning procedures in the inanimate ward environment might play a key role in controlling VRE. In order to optimize infection control management at University Hospital Frankfurt, Germany (UHF), this study evaluates the impact of H₂O₂-containing cleaning wipes compared to Glucoprotamin containing wipes on VRE prevalence in intensive care wards.

Methods: Retrospective analyses were conducted of the VRE prevalence on environmental materials obtained from three intensive care units (ICU) at UHF for 17 months prior to (T1) and during the 25 months after (T2) the implementation of H₂O₂-containing cleaning wipes from January 2016 to June 2019. The bactericidal power of the two disinfectants against VRE was compared using the 4-field test according to EN 16615 (2015).

Results: At T1 and T2, n=666 and n=710 environmental samples, respectively, were obtained. At T1, 24.2% (n=161/666; 95% confidence interval: 21.0–27.6) and at T2, 6.9% (n=49/710; 5.1–9.0) samples were positive for VRE. In vitro disinfectant testing did not reveal any superiority of H₂O₂ over glucoprotamin. No effect on the VRE prevalence in patients’ rectal screening materials was observed.

Conclusion: Though Glucoprotamin and H₂O₂ were in vitro equally effective against VRE, the prevalence of VRE in ICU environment at UHF decreased after implementation of H₂O₂-containig wipes. This might be due to multiple factors, of which we consider the impact of the Hawthorne effect to be the strongest. Success of infection control strategies might depend on the compliance of the persons critically involved. Transparent information on infection control strategies is suggested to increase compliance and should therefore be considered both in daily infection control and outbreak management.

Children and adolescents in the CoVid-19 pandemic: Schools and daycare centers are to be opened again without restrictions. The protection of teachers, educators, carers and parents and the general hygiene rules do not conflict with this

In the opinion of the medical societies of hygiene and pediatrics undersigning the present statement, the analyses published to date regarding transmission of SARS-CoV-2 and the course of CoVid-19 show that children play a much less significant role in the spread of the virus than do adults.

According to the findings available to date, not only do children and adolescents less frequently fall ill with CoVid-19, they also generally become less severely ill than do adults. The vast majority of infections in children and adolescents are asymptomatic or oligosymptomatic. Even the first analyses from China demonstrated that children and adolescents play a subordinate role in the transmission of the virus – not only to other children and adolescents, but also to adults.

Taking into account regional infection rates and available resources, daycare centers, kindergartens and elementary schools promptly should be reopened. For children, this should be possible without excessive restrictions, such as clustering into very small groups, implementation of barrier precautions, maintaining appropriate distance from others or wearing masks. A factor more decisive than individual group size is the issue of sustaining the constancy of respective group members and the avoidance of intermixing. Children can be taught basic rules of hygiene such as handwashing and careful hygiene behavior when coming into contact with others during mealtimes and/or when using sanitary facilities. Independent of the prevention measures implemented for children and adolescents, the protection of teachers, educators and caregivers is crucial, (e.g., the maintenance of appropriate distance from others, use of medical masks, situation-dependent hand disinfection, when necessary, supported by regular pool testing). Children over the age of 10 and adolescents up to school graduation age are more capable of actively understanding and conforming to specific hygiene rules. For this group, maintaining appropriate distance from others (1.5 meters), wearing a mouth-and-nose protection (whenever they are not sitting in their assigned classroom seats) and consistent education regarding the basic rules of infection prevention may provide increased options for normalizing teaching activities. Children and adolescents suspected of infection with SARS-CoV-2 should be tested immediately in order to either confirm or rule out such an infection. Evidence of individual infections in children or students must not automatically lead to the closure of the entire daycare center or school. A detailed analysis of the chain of infection is a prerequisite for a balanced approach to infection control. The opening of schools and children’s facilities should be accompanied by specifically structured, model surveillance studies that further clarify outstanding questions about infectious disease events and hygiene control. These prospective, concomitant examinations will be essential for the purpose of evaluating and verifying the effectiveness of the required hygiene measures.

Test methods for surface disinfection: comparison of the Wiperator ASTM standard E2967-15 and the 4-field test EN 16615

Aim: Two test methods for surface disinfection (phase 2, step 2) – the Wiperator method (ASTM standard E2967-15) and the 4-field test (EN 16615) – were compared using a disinfectant solution based on quaternary ammonium compounds and a ready-to-use alcohol-based wipe. As test organisms, Staphylococcusaureus and Pseudomonasaeruginosa were used.

Results: While the 4-field test is a manual method and better reflects the process in practice, with the Wiperator, the wiping process is better controlled because it is an automated procedure. A comparison of the effects of both methods on the target log₁₀-reduction of S. aureus and P. aeruginosa indicates a statistically significant difference between the two test methods (Mann-Whitney U-Test. S. aureus: 0 (U_min)<4 (U_crit); n₁=8, n₂=8, p=0.001; 2-sided. P. aeruginosa: 24 (U_min)<26 (U_crit); n₁=11, n₂=10, p=0.025, 2-sided). In addition, the results indicate that the wipe used has a major influence on the success of the disinfection process.

Discussion: Both methods are suitable for efficacy studies of surface disinfectants, yet they differ in some aspects. Additionally our data indicate a statistically significant difference between the two test methods.

Conclusion: Efficiency testing of surface disinfection is a complex process that depends on many different parameters. Since the 4-field test better reflects the practice, it makes sense to stick to this test procedure, taking into account that the EN 16615 was approved by CEN TC 216 in 2015 after method validation ring trials.

Questionnaire based evaluation of the motivation of surgically treated patients to participate in preventative hygiene measures

Background: Nosocomial infections caused by antibiotic-resistant pathogens demonstrate the continued need for preventive hygiene management strategies. Information and training of patients in their personal hygiene is a current requirement of the German Society for Hospital Hygiene, and is recommended by the Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention beim Robert-Koch Institut, KRINKO) at the Robert Koch Institute.

Aim: The aim of this study was to evaluate patients’ existing knowledge of hygiene and their motivation to actively participate in preventive hygiene measures.

Methods: This study included 445 inpatients at the Polyclinic for Surgery of University Hospital Bonn. Subjects were interviewed over a 6-month period using a questionnaire comprising 21 questions on the topic of hygiene.

Results: The majority of patients rated their subjective level of knowledge as intermediate (41%), 25% as poor and 35% as high. The respondents rated the active inclusion of patients in hygiene practices as highly relevant, and were willing to actively contribute to infection prevention, whereby the patients considered hand washing and hand disinfection in particular as important starting points. 78% of the respondents wanted more information on hygiene, particularly on wound and food hygiene. Targeted hygiene education provided by hospital staff had a positive effect on the patients’ subjective level of information, as well as on their confidence in physicians and nursing staff. Previous information via television or radio had a negative impact on the patients’ subjective information level and on their confidence in hospital staff.

Conclusion: Most surgically treated patients are motivated to actively contribute to preventive hygiene measures. This represents an additional and important option for applying hospital hygiene more effectively and, above all, closer to the patient. Information and education should preferably be performed by healthcare professionals.

Association between antibiotic residues, antibiotic resistant bacteria and antibiotic resistance genes in anthropogenic wastewater - An evaluation of clinical influences

The high use of antibiotics in human and veterinary medicine has led to a wide spread of antibiotics and antimicrobial resistance into the environment. In recent years, various studies have shown that antibiotic residues, resistant bacteria and resistance genes, occur in aquatic environments and that clinical wastewater seems to be a hot spot for the environmental spread of antibiotic resistance. Here a representative statistical analysis of various sampling points is presented, containing different proportions of clinically influenced wastewater. The statistical analysis contains the calculation of the odds ratios for any combination of antibiotics with resistant bacteria or resistance genes, respectively. The results were screened for an increased probability of detecting resistant bacteria, or resistance genes, with the simultaneous presence of antibiotic residues. Positive associated sets were then compared, with regards to the detected median concentration, at the investigated sampling points. All results show that the sampling points with the highest proportion of clinical wastewater always form a distinct cluster concerning resistance. The results shown in this study lead to the assumption that ciprofloxacin is a good indicator of the presence of multidrug resistant P. aeruginosa and extended spectrum β-lactamase (ESBL)-producing Klebsiella spec., Enterobacter spec. and Citrobacter spec., as it positively relates with both parameters. Furthermore, a precise relationship between carbapenemase genes and meropenem, regarding the respective sampling sites, could be obtained. These results highlight the role of clinical wastewater for the dissemination and development of multidrug resistance.

Air quality in the operating room: Surgical site infections, HVAC systems and discipline - position paper of the German Society of Hospital Hygiene (DGKH)

In recent years, there has been an ongoing discussion about the value of laminar airflow (LAF=low turbulence displacement ventilation) in the operating room for prevention of surgical site infections (SSI). Some publications, e.g., from the WHO, issued the demand to no longer build LAF ceilings in operating rooms. The present statement deals critically with this position and justifies the use of LAF ceilings in different ways: Many of the papers cited by the WHO and others for the case against LAF do not provide reliable data.The remaining studies which might be used for answering the question give quite different results, also in favor of LAF.The size of the LAF ceiling in many studies is not given or mostly too small in comparison to actual technical requirements.LAF in different countries can mean quite different techniques (e.g., the US in comparison to Germany) so that the results of studies that do not take this into account may not be comparable.LAF has positive effects in terms of reducing particulate and bacterial load, associated with increased airflow in the surgical working area. A reduction of carcinogenic substances in the air may also be assumed, which would increase workers' safety. Thus, this paper recommends building LAF ceilings in the future as well, depending on the operations intended. Further, this paper gives an overview of possible reasons for surgical site infections and highlights the importance of discipline in the operating theatre.

[Personal preconditions for the prevention of nosocomial infections-guidelines of the German Commission for Hospital Hygiene and Infection Prevention (KRINKO), federal state hygiene regulations in Germany, and compliance by hospitals in Frankfurt am Main]

According to the amendment of the Infection Protection Act (2011), § 23, 8, all federal states in Germany had to pass their own hospital hygiene regulations, in which the need for hygiene specialists in a hospital is defined.This publication explains in its first part the differences between the nationwide Commission for Hospital Hygiene and Infection Prevention (KRINKO) regulations and the hygiene regulations of the different federal states (Hesse, Bavaria, etc.). All federal states - with the exception of Hesse (Hessian Hygiene Regulation, HHygVO) - refer to the relevant expert recommendations of KRINKO.In a second part of this publication, we highlight differences between KRINKO and HHygVO with the example of hospitals in the city of Frankfurt. In 2017, all Frankfurt hospitals had the necessary hygiene specialists (authorized hygiene practitioners, infection control nurses, authorized hygiene care nurses). However, the need for hospital hygienists could not be met, because there is an insufficient number of physician specialists for hospital hygiene available in Germany.The hospitals cannot solve this problem on their own - a political, superordinate decision and regulation must be made, i. e. by regulation and financial support for the advanced training of post-graduate physicians in hygiene. This is important since only experienced hospital hygienists can instruct or supervise hygiene specialists-in-training.

Interlaboratory reproducibility of a test method following 4-field test methodology to evaluate the susceptibility of Clostridium difficile spores

BACKGROUND

Sporicidal surface disinfection is recommended to control transmission of Clostridium difficile in healthcare facilities. EN 17126 provides a method to determine the sporicidal activity in suspension and has been approved as a European standard. In addition, a sporicidal surface test has been proposed.

AIM

To determine the interlaboratory reproducibility of a test method for evaluating the susceptibility of a C. difficile spore preparation to a biocidal formulation following the 4-field test (EN 16615 methodology).

METHODS

Nine laboratories participated. C. difficile NCTC 13366 spores were used. Glutaraldehyde (1% and 6%; 15 min) and peracetic acid (PAA; 0.01% and 0.04%; 15 min) were used to determine the spores' susceptibility in suspension in triplicate.

FINDINGS

One-percent glutaraldehyde revealed a mean decimal log₁₀ reduction of 1.03 with variable results in the nine laboratories (0.37-1.49) and a reproducibility of 0.38. The effect of 6% glutaraldehyde was stronger (mean: 2.05; range: 0.96-4.29; reproducibility: 0.86). PAA revealed similar results. An exemplary biocidal formulation based on 5% PAA was used at 0.5% (non-effective concentration) and 4% (effective concentration) to determine the sporicidal efficacy (4-field test) under clean conditions in triplicate with a contact time of 15 min. When used at 0.5% it demonstrated an overall log₁₀ reduction of 2.68 (range: 2.35-3.57) and at 4% of 4.61 (range: 3.82-5.71). The residual contamination on the three primarily uncontaminated test fields was <50 cfu/25 cm² in one out of nine laboratories (0.5%) and in seven out of nine laboratories (4%).

CONCLUSION

The interlaboratory reproducibility seems to be robust.

[Facial necrosis caused by orthopoxvirus : Differential diagnosis and dermatohistopathological correlation of infectious facial ulcers]

This article reports the remarkable course of a facial ulcer in a patient receiving prednisolone for Crohn's disease. Based on the initially unclear origin of the ulcer the patient received a triple anti-infective treatment (antiviral, antibiotic, antimycotic) but the lesion showed a rapid progression. An orthopoxvirus infection could be verified later by extensive diagnostics and relevant differential diagnoses could be ruled out. Extensive necrotic changes were observed in the first weeks resulting in cicatricial healing after months. Human cowpox infections have been repeatedly reported in Germany and are a relevant zoonosis. Cats and rodents are main carriers. The differential diagnoses include infections caused by other bacterial, mycobacterial, mycotic and parasitic agents that are thoroughly discussed here both clinically and histopathologically. Especially cutaneous leishmaniasis must be named as the incidence is continuously rising. With inadequate treatment infectious facial ulcers may give rise to life-threatening complications and extensive disfiguring scarring, therefore treatment must be initiated in a timely manner.

Antibiotic resistant bacteria and resistance genes in biofilms in clinical wastewater networks

Increasing isolation rates of resistant bacteria in the last years require identification of potential infection reservoirs in healthcare facilities. Especially the clinical wastewater network represents a potential source of antibiotic resistant bacteria. In this work, the siphons of the sanitary installations from 18 hospital rooms of two German hospitals were examined for antibiotic resistant bacteria and antibiotic residues including siphons of showers and washbasins and toilets in sanitary units of psychosomatic, haemato-oncological, and rehabilitation wards. In addition, in seven rooms of the haemato-oncological ward, the effect of 24 h of stagnation on the antibiotic concentrations and MDR (multi-drug-resistant) bacteria in biofilms was evaluated. Whereas no antibiotic residues were found in the psychosomatic ward, potential selective concentrations of piperacillin, meropenem and ciprofloxacin were detected at a rehabilitation ward and ciprofloxacin and trimethoprim were present at a haemato-oncology ward. Antibiotic resistant bacteria were isolated from the siphons of all wards, however in the psychosomatic ward, only one MDR strain with resistance to piperacillin, third generation cephalosporins and quinolones (3MRGN) was detected. In contrast, the other two wards yielded 11 carbapenemase producing MDR isolates and 15 3MRGN strains. The isolates from the haemato-oncological ward belonged mostly to two specific rare sequence types (ST) (P. aeruginosa ST823 and Enterobacter cloacae complex ST167). In conclusion, clinical wastewater systems represent a reservoir for multi-drug-resistant bacteria. Consequently, preventive and intervention measures should not start at the wastewater treatment in the treatment plant, but already in the immediate surroundings of the patient, in order to minimize the infection potential.

Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review

Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.

Isopropanol at 60% and at 70% are effective against 'isopropanol-tolerant' Enterococcus faecium

The bactericidal activity of isopropanol was determined against Enterococcus faecium ATCC 6057, ST 796 (isopropanol-tolerant strain) and Enterococcus hirae ATCC 10541 (EN 13727). Isopropanol at 60% and 70% were effective (≥5.38 log₁₀-reduction) in 15 s against all strains but 23% isopropanol was not (<0.99 log₁₀-reduction in ≤15 min). Isopropanol at 70% was tested against E. faecium in the four-field test. Eight millilitres was not effective enough in 1 min (<5 log₁₀-reduction), whilst 16 mL was effective (≥5.85 log₁₀-reduction). Healthcare workers can be reassured that 60% and 70% isopropanol with an appropriate volume are effective against E. faecium.

The occurrence of antimicrobial substances in toilet, sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference. To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02 μg·L^-1 to a maximum of 79 mg·L^-1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.

Lelliottia aquatilis sp. nov., isolated from drinking water

Five beige-pigmented, oxidase-negative bacterial isolates, 6331-17^T, 6332-17, 6333-17, 6334-17 and 9827-07, isolated either from a drinking water storage reservoir or drinking water in 2006 and 2017 in Germany, were examined in detail applying by a polyphasic taxonomic approach. Cells of the isolates were rod-shaped and Gram-stain-negative. Comparison of the 16S rRNA gene sequences of these five isolates showed highest sequence similarities to Lelliottia amnigena (99.98 %) and Lelliottia nimipressuralis (99.99 %). Multilocus sequence analyses based on concatenated partial rpoB, gyrB, infB and atpD sequences confirmed the clustering of these isolates with Lelliottia species, but also revealed a clear distinction to the closest related type strains. Analysis of the genome sequences of these isolates indicated >70 % in silico DNA-DNA hybridization and high average nucleotide identities between strains. Nevertheless, they showed only <70 and <95 % similarity to the type strains of these two Lelliottia species. The fatty acid profiles of these isolates were very similar and consisted of the major fatty acids C16:0, C17 : 0cyclo, C15 : 0iso 2-OH/C16 : 1ω7c and C18 : 1ω7c. In addition, physiological/biochemical tests revealed high phenotypic similarity to each other. These cumulative data indicate that these isolates represent a novel Lelliottia species, for which the name Lelliottia aquatilis sp. nov. is proposed, with strain 6331-17^T (=CCM 8846^T=CIP 111609^T=LMG 30560^T) as the type strain.