Antibacterial and Disinfecting Effects of Standardised Tea Extracts on More than 100 Clinical Isolates of Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) infections are still a major problem in hospitals. The excellent safety profile, accessibility and anti-infective activity of tea extracts make them promising agents for the treatment of infected wounds. To investigate the possibility of sterilising MRSA-infected surfaces, including skin with tea extracts, we determined the MICs for different extracts from green and black tea (Camellia sinensis), including epigallocatechin gallate (EGCG), on a large number of clinical isolates of MRSA, selected to represent a high genetic diversity. The extracts were prepared to achieve the maximal extraction of EGCG from tea and were used as stable lyophilisate with a defined EGCG content. All extracts showed a complete inhibition of cell growth at a concentration of approx. 80 µg/mL of EGCG after a contact time of 24 h. Time-kill plots were recorded for the extract with the highest amount of EGCG. The reduction factor (RF) was 5 after a contact time of 240 min. EGCG and tea extracts showed an RF of 2 in methicillin-sensitive S. aureus. Extracts from green and black tea showed lower MICs than an aqueous solution with the same concentration of pure EGCG. To the best of our knowledge, we are the first to show a reduction of 99.999% of clinically isolated MRSA by green tea extract within 4 h.

Characteristics and mechanisms to control a COVID-19 outbreak on a leukemia and stem cell transplantation unit.

Immunosuppressed patients like patients with leukemia or lymphoma, but also patients after autologous or allogeneic stem cell transplantation are at particular risk for an infection with COVID-19. We describe a COVID-19 outbreak on our leukemia and stem cell transplantation unit (LSCT-Unit) originating from a patient with newly diagnosed acute myeloid leukemia. The patient was treated with intensive induction chemotherapy and we characterize the subsequent outbreak of COVID-19 on a LSCT-Unit. We describe the characteristics of the 36 contacts among the medical team, the results of their PCR and antibody tests and clinical aspects and features of infected employees. Of these 36 close contacts, 9 employees of the LSCT-Unit were infected and were tested positive by PCR and/or antibody-testing. 8/9 of them were symptomatic, 3/9 with severe, 5/9 with mild symptoms, and one person without symptoms. Due to stringent hygiene measures, the outbreak did not lead to infections of other patients despite ongoing clinical work. Moreover, we demonstrate that incubation period and clinical course of a COVID-19 infection in an immunosuppressed patient could be unusual compared to that of immunocompetent patients. Consistent PCR and antibody testing are helpful to understand, control, and prevent outbreaks. For the safety of health-care workers and patients alike, all employees wore FFP2 masks and were trained to adhere to several further safety guidelines. The implementation of rigorous hygiene measures is the key to controlling an outbreak and preventing infections of other patients.

Thirty years of VRE in Germany - "expect the unexpected": The view from the National Reference Centre for Staphylococci and Enterococci.

Enterococci are commensals of the intestinal tract of many animals and humans. Of the various known and still unnamed new enterococcal species, only isolates of Enterococcus faecium and Enterococcus faecalis have received increased medical and public health attention. According to textbook knowledge, the majority of infections are caused by E. faecalis. In recent decades, the number of enterococcal infections has increased, with the increase being exclusively associated with a rising number of nosocomial E. faecium infections. This increase has been accompanied by the dissemination of certain hospital-acquired strain variants and an alarming progress in the development of antibiotic resistance namely vancomycin resistance. With this review we focus on a description of the specific situation of vancomycin resistance among clinical E. faecium isolates in Germany over the past 30 years. The present review describes three VRE episodes in Germany, each of which is framed by the beginning and end of the respective decade. The first episode is specified by the first appearance of VRE in 1990 and a country-wide spread of specific vanA-type VRE strains (ST117/CT24) until the late 1990s. The second decade was initially marked by regional clusters and VRE outbreaks in hospitals in South-Western Germany in 2004 and 2005, mainly caused by vanA-type VRE of ST203. Against the background of a certain "basic level" of VRE prevalence throughout Germany, an early shift from the vanA genotype to the vanB genotype in clinical isolates already occurred at the end of the 2000s without much notice. With the beginning of the third decade in 2010, VRE rates in Germany have permanently increased, first in some federal states and soon after country-wide. Besides an increase in VRE prevalence, this decade was marked by a sharp increase in vanB-type resistance and a dominance of a few, novel strain variants like ST192 and later on ST117 (CT71, CT469) and ST80 (CT1065). The largest VRE outbreak, which involved about 2,900 patients and lasted over three years, was caused by a novel and until that time, unknown strain type of ST80/CT1013 (vanB). Across all periods, VRE outbreaks were mainly oligoclonal and strain types varied over space (hospital wards) and time. The spread of VRE strains obviously respects political borders; for instance, both vancomycin-variable enterococci which were highly prevalent in Denmark and ST796 VRE which successfully disseminated in Australia and Switzerland, were still completely absent among German hospital patients, until to date.

[Costs associated with multiresistant bacteria in neurorehabilitation]. / Mehrkosten durch multiresistente Erreger in der Neurorehabilitation.

BACKGROUND AND OBJECTIVES: The number of patients with multiresistant bacteria (MRB) in rehabilitation facilities is increasing. The increasing costs of hygienic isolation measures reduce resources available for core rehabilitation services. In addition to the existing lack of care, patients with MRB are at further risk of being given lower priority for admission to rehabilitation facilities. Therefore, the Hygiene Commission of the German Society for Neurorehabilitation (DGNR) attempted to quantify the overall risk for deterioration of rehabilitation care due to the financial burden of MRB. MATERIALS AND METHODS: To analyze the added costs associated with the rehabilitation of patients with MBR, the DGNR Hygiene Commission identified criteria for a cost assessment. Direct (consumables, personnel and miscellaneous costs) and indirect costs of loss of opportunity were evaluated in seven neurorehabilitation centers in different states across Germany. RESULTS: On average, hygienic isolation measures amounted to direct costs of 144 € per day (47 € consumables, 92 € personnel, 5 € for other costs such as extra transportation expenditure) and indirect costs of 274 €, totaling 418 € per patient with MRB per day. Given that approximately 10% of patients had MRB, the added costs of hygienic isolation measures equaled about one tenth of the overall budget of a rehabilitation center and can be expected to rise with the increasing numbers of patients with MRB. CONCLUSIONS: Admission of patients carrying MRB to neurorehabilitation centers triggers added costs that critically diminish the overall capacity for centers to provide their core rehabilitation services.

Molecular characterisation of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli isolates from hospital and ambulatory patients in Germany.

The increase of Escherichia coli producing extended-spectrum ß-lactamases (ESBL) in hospitals and their emergence as intestinal colonisers of healthy humans is of concern. Transmission ways and the extent of spread of distinct E. coli clones or ESBL genes among humans and animals via the food chain or the environment is a matter of debate. In this study we determined ESBL genotypes in E. coli isolates (n=233) resistant to 3rd generation cephalosporins from hospitals and medical practices using PCR and sequencing. Bacterial strain typing was performed by PCR-based phylogrouping, multilocus sequence typing (MLST) and a ST131-specific PCR. Results showed that CTX-M-15 (50.4%), CTX-M-1 (28.4%) and CTX-M-14 (5.6%) were the most common ESBL types. Especially, CTX-M-15 was associated with E. coli ST131 of phylogenetic group B2, which was the dominant sequence type among our isolates (35.8%). MLST typing revealed 40 different sequence types (STs), with ST131, ST410, ST10 and ST38 as the most prevalent ones. Our findings give an overview of the current distribution of ESBL-producing E. coli isolates from humans in Germany. E. coli O25b:H4-ST131 was confirmed to be the most common clone, which is known for its successful dissemination worldwide. Although heterogeneity among the isolates was found, several successful clones previously described in animals (ST410, ST10) also occurred in our isolate collection. Further detailed investigations of ESBL-producing isolates from different habitats are needed to evaluate possible transfer ways.

Cross-border comparison of the Dutch and German guidelines on multidrug-resistant Gram-negative microorganisms.

BACKGROUND: In all European countries, hospital-acquired infections caused by Gram-negative multidrug-resistant microorganisms (GN-MDRO) are a major health threat, as these pathogens cannot be adequately treated anymore, or the start of effective antibiotic treatment is delayed. The efforts to limit the selection and spread of GN-MDRO remains a problem in cross-border healthcare, as the national guidelines on hygiene standards applicable for patients colonized or infected with GN-MDRO in hospitals are not harmonized between European countries. METHODS: In order to point out the similarities and differences in the national guidelines of Germany and The Netherlands regarding GN-MDRO, guidelines were compared and an expert workshop was organized by the INTERREG IVa project EurSafety Health-net. RESULTS: Both guidelines divide the Gram-negative organisms into subgroups based on bacterial species and antibiotic susceptibility patterns in order to define multidrug-resistant variants of these bacteria. However, the Dutch guideline defines that GN-MDRO Enterobacteriaceae requires testing for certain mechanisms causing antibiotic resistance, whereas the German guideline makes use of a newly created classification scheme, based on phenotypic characterization. Besides diagnostic issues, the main difference between the Dutch and German guideline is the divergent evaluation of ESBL-producing Enterobacteriaceae. Special hygiene measures are required for all patients with ESBL-producing Enterobacteriaceae in The Netherlands, whereas the German guideline recommends special precautions only for those cases in which patients are colonized or infected with strains showing co-resistance to ciprofloxacin ("3MRGN"). CONCLUSIONS: The usage of consistent terminology and harmonized diagnostic procedures would improve the possibilities for infection prevention, treatment and patient safety. Prevention of severe non-treatable infections and outbreaks due to MDRO, caused by an increased population seeking medical treatment abroad together with an increased number of highly susceptible individuals demands gathering of regional data, and data comparable between the two sides of the Dutch-German border. The necessity to cooperate multidisciplinary and across borders is required to prevent a post-antibiotic era - in which common infections and minor injuries may lead to death.

Complete Nucleotide Sequence of a Citrobacter freundii Plasmid Carrying KPC-2 in a Unique Genetic Environment.

The complete and annotated nucleotide sequence of a 54,036-bp plasmid harboring a blaKPC-2 gene that is clonally present in Citrobacter isolates from different species is presented. The plasmid belongs to incompatibility group N (IncN) and harbors the class A carbapenemase KPC-2 in a unique genetic environment.

Comparison of direct cultivation on a selective solid medium, polymerase chain reaction from an enrichment broth, and the BD GeneOhm™ VanR Assay for identification of vancomycin-resistant enterococci in screening specimens.

Fast and reliable diagnostics of vancomycin-resistant enterococci (VRE) is an important prerequisite for containing VRE transmission rates and controlling VRE outbreaks among hospital patients. The BD GeneOhm™ VanR Assay (Becton Dickinson Diagnostics, Erembodegem, Belgium) is a real-time polymerase chain reaction (PCR) assay for screening perianal/rectal samples for the presence of vanA or vanB genes that can be associated with VRE. A set of 51 reference strains (vanA-G genotypes) were correctly identified. Performance of the assay was evaluated and compared with culture-based methods and subsequent PCR analysis in 2 university hospitals with a different VRE prevalence. A total of 1786 samples were analyzed. With the use of the BD GeneOhm™ VanR Assay, 88 of 102 vanA-positive specimens, 62 of 67 vanB-positive specimens, 3 of 4 vanA- and vanB-positive specimens, and 1403 of 1613 negative specimens were correctly identified. The overall sensitivity was 93.1%; the specificity was 87.0% mainly due to false-positive vanB results. Results did not differ between study institutions.

Evidence-based spectrum of antimicrobial activity for disinfection of bronchoscopes.

UNLABELLED: Processing of bronchoscopes after a physical examination has to eliminate all micro-organisms that could have contaminated the endoscope and that may harm the following patient. The aim of this analysis is to define those micro-organisms that may contaminate the bronchoscope during the examination and that may cause disease in other patients. METHODS: Research of literature and analysis of laboratory data. RESULTS: During the passage of the respiratory tract the bronchoscope will be contaminated by the physiological flora of oral cavity, nasopharynx, trachea, bronchi, and pulmonary tissues. Whilst the oral cavity, the nasopharynx and the pharynx are the habitat for a great variety of bacteria the lower respiratory tract is virtually free of micro-organisms. However, in ventilated patients trachea and bronchi can become colonized as the result of bypassing the cleansing effect of the ciliated epithelium. In addition all agents that can cause bronchitis or pneumonia in immunocompromised or otherwise healthy individuals are potential contaminants of bronchoscopes. These microorganisms include bacteria, mycobacteria, yeasts and moulds, enveloped and non-enveloped viruses and rarely parasites. The bronchoscopic procedure can result in epithelial injury with subsequent bleeding. Therefore, all blood-borne pathogens, e.g. HIV or HBV are also potential contaminants of the bronchoscope. There are several reports of transmission of micro-organisms due to incomplete or faulty cleaning and disinfection procedures of bronchoscopes. These incidents include nearly all classes of micro-organisms but not parasites or viruses. However, the incubation period of viruses can be long and the association between bronchoscopy and infection may be obscure. Endospore forming micro-organisms and parasites are not part of the normal flora of the respiratory tract and may rarely cause disease, usually only in severely immunocompromised patients, but transmission of such organisms by bronchoscopy has never been reported. CONCLUSION: The antimicrobial activity of the disinfection process, including chemical disinfectants for endoscopes has to include bacteria, fungi and viruses. Sporicidal activity may be only warranted in specific patient populations, i.e. after bronchoscopy of suspected anthrax patients or before examination of severely immunocompromised patients.

Staphylococcus aureus-induced plasmacytoid dendritic cell activation is based on an IgG-mediated memory response.

Type I IFNs represent a major antimicrobial defense mechanism due to their property of enhancing immune responses by priming both innate and adaptive immune cells. Plasmacytoid dendritic cells (pDC) are the major source of type I IFN in the human body and represent innate immune cells involved in first-line defense against invading pathogens. Although pDC activation has been extensively studied upon stimulation with synthetic TLR ligands, viruses, and intracellular bacteria, there is only scarce information on extracellular bacteria. In this study we show that the triggering of human pDC-derived IFN-alpha secretion by Staphylococcus aureus is independent of TLR2 and specific for coagulase-positive staphylococci. Specificity of the pDC response to S. aureus is independent of the bacterial virulence factors protein A and alpha-toxin but is mediated by Ag-specific IgG and CD32. S. aureus-induced pDC activation can be blocked by inhibitory DNA oligonucleotides and chloroquine, suggesting that engagement of TLR7/9 by bacterial nucleic acids after CD32-mediated uptake of these compounds may play a central role in this process. Altogether, we propose that in marked contrast to nonselective TLR2-dependent activation of most innate immune cells, pDC activation by S. aureus represents an Ag-specific memory response since it requires the presence of class-switched immunoglobulins.

Staphylococcus aureus in dermatology outpatients with special emphasis on community-associated methicillin-resistant strains.

Methicillin-resistant Staphylococcus aureus (MRSA) emerged as a community-associated pathogen (CA-MRSA) in the past 6 years. This prospective study investigated dermatology outpatients with inflammatory skin diseases, leg ulcers, and skin infections for Panton-Valentine leukocidin (PVL)-positive S. aureus, often associated with deep skin infection. In case of PVL positivity, molecular typing and PCR demonstration of resistance genes were performed. Out of 248 patients, 130 carried S. aureus, 24 being lukS-PV lukF-PV positive. Eighteen were MRSA, 11 of them belonging to the multilocus sequence typing clonal complex (CC)5, 1 to CC45, and 2/18 to CC8. Out of 18 patients, 4 were CA-MRSA containing lukS-PV lukF-PV as an important trait of CA-MRSA. Out of four CA-MRSA isolates, two were of type ST080 containing far-1 coding for fusidic acid (FUS) resistance and two were FUS sensitive (ST152 and ST001). The FUS-sensitive CA-MRSA, which corresponded to the CA-MRSA of ST001 from the United States, was detected in Germany for the first time, indicating that dermatologists are first in line to detect CA-MRSA. In contrast to CA-MRSA from other continents, far-1-coded FUS resistance represents a typical marker for the widespread CA-MRSA ST080 in Europe, especially in Germany. The significant risk factor for the acquisition of CA-MRSA was visits to foreign countries and/or professional or private contacts with foreigners.

Tigecycline for the treatment of patients with severe sepsis or septic shock: a drug use evaluation in a surgical intensive care unit.

OBJECTIVES: Adequate antimicrobial therapy is crucial for the survival of critically ill patients with severe nosocomial infections. Tigecycline, the first available agent in the new class of glycylcyclines, is active against multiresistant gram-positive and gram-negative bacteria. The aim of this observational, retrospective evaluation was to assess tigecycline use patterns in a surgical intensive care unit (SICU) of a tertiary care centre. METHODS: Data from 70 patients receiving tigecycline in the SICU were analysed. We reviewed tigecycline use in terms of demographic data and co-morbidities, disease severity, clinical indication, microbiology, therapy regimens and mortality. A logistic regression analysis was performed to identify prognostic factors for mortality. RESULTS: The majority of patients had co-morbidities such as cancer (51%) or renal replacement therapy (57%). The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score of patients at admission was 27. Intra-abdominal infection was most frequently diagnosed (50% of patients); intra-abdominal infection and pneumonia were diagnosed in 14%. Methicillin-resistant Staphylococcus aureus was found in 16% of patients (colonization; infection: 6%) and vancomycin-resistant enterococci in 27% (colonization; infection: 21%). The mean duration of tigecycline therapy was 9 +/- 4 days; 76% of patients received tigecycline in combination, with 64% being treated second line. APACHE score and renal replacement were identified as predictive factors for mortality. SICU mortality was 30%. CONCLUSIONS: Tigecycline treatment of critically ill SICU patients with severe sepsis or septic shock appeared to result in remarkably low mortality. Tigecycline may be an important treatment option for septic patients with infections resistant to other available agents.

Genetic diversity of Legionella pneumophila in hospital water systems.

It has been shown that different patients who had acquired legionellosis in a hospital setting were infected with the same strain even years apart. However, there are no longitudinal data describing the molecular epidemiology of Legionella pneumophila strains that contaminate a water system. This raised the question if there are any shifts of L. pneumophila strains over time, or after carrying out control measures. Using genotyping on a large collection of isolates, we investigated in a retrospective study the distribution of L. pneumophila serogroups and PFGE types in six different hospitals of the University of Heidelberg between 1991 and 2001. A total of 2012 water samples were drawn for routine testing and for evaluation of control measures, 747 samples were positive for L. pneumophila. Serogroups were determined by latex agglutination or by direct fluorescence assay; and 515 L. pneumophila isolates from water systems and six from patients underwent PFGE typing after SfiI-restriction. We identified seven serogroups and 19 genotypes among the water isolates. Each hospital had one to four predominating PFGE types that were stable over the investigation period. The oldest buildings in hospitals 4 and 5 (built 1876 and 1907) had more types than the newest one (built 1986). In all hospitals PFGE types were identified that could be found only sporadically. Although each hospital had its own warm water supply, we identified types that could be found in more than one hospital. However, there was no overlap of types in buildings that were fed from different wells. Infrequently occurring nosocomial legionellosis (n=3) were only caused by predominant strains. Contamination of water supplies seemed to be dominated by stable genotypes, even after various control measures. Additional genotypes could be isolated sporadically, however, their pathogenetic relevance seemed to be questionable.

Longitudinal study of the molecular epidemiology of methicillin-resistant Staphylococcus aureus at a university hospital.

Surveillance for methicillin-resistant Staphylococcus aureus (MRSA) at the University Hospital of Heidelberg revealed an increase in the numbers of newly detected MRSA isolates in recent years. We conducted a study to assess the dynamics of the changes in the MRSA population. Pulsed-field gel electrophoresis (PFGE) typing of MRSA isolates from all patients at the University Hospital of Heidelberg collected between 1993 and 2004 was performed. The microbiology database contained 1,807 entries for newly detected MRSA isolates from 1,301 patients. A total of 1,252 isolates were available for PFGE typing. The isolates could be classified into 109 different PFGE types. Most PFGE types (n=70) were detected less than five times and showed no evidence of transmission (sporadic strains). They accounted for 8.7% of all isolates, with few variations in frequency over the time. Thirty-seven PFGE types were clustered by time of detection, and transmission of the strains was likely (local epidemic strains). A total of 37.3% of the isolates belonged to this group of strains. The remaining 54.0% of the isolates belonged to only two further PFGE types (endemic strains). One endemic strain accounted for 5.0% of all isolates in 1994 and 68.2% in 2004. A second endemic strain was detected in 1.1% of all isolates in 1998 but in 12.4% in 2004. Statistical analysis of the associations between the kind of strain (sporadic, local epidemic, or endemic) and the patients' characteristics revealed a significant association for age and mode of acquisition. The remarkable increase in the rate of MRSA detection at the University Hospital of Heidelberg is mainly due to the dissemination of two different strains. Infection control measures seemed sufficient to prevent further transmission of some but not all of the strains.

Infection control in German nursing homes.

Infection control in German nursing homes has become an issue during the past 10 years. The changing demographics and the introduction of the diagnosis-related group reimbursement system, as well as the increasing number of residents who are colonized with methicillin-resistant Staphylococcus aureus, may worsen already-existing infection control problems. The publication of national infection control guidelines for nursing homes that should be implemented and supervised by infection control nurses may increase the standard. However, the lack of responsibility of the caring physicians for the whole population of a nursing home may hinder the process. This article discusses the state of infection control in German nursing homes.

Survival of cephalosporin-resistant enterobacteriaceae on fingers.

Five strains of Enterobacter species (n=4) and Pantoea species (n=1) resistant to third-generation cephalosporins and isolated from clusters of 3-25 premature infants and small children and 5 strains (4 Enterobacter strains and 1 Pantoea strain) with the same resistance pattern that were isolated from 1 premature infant or small child each were inoculated on the fingertips of 10 volunteer study participants to test whether survival on fingertips is correlated with horizontal transmission. Although there was no significant difference in survival between the groups of transmitted and sporadic strains, there were significant differences in bacterial survival between the participants.

Molecular evidence of Pneumocystis transmission in pediatric transplant unit.

We describe an outbreak of Pneumocystis jirovecii pneumonia in a pediatric renal transplant unit, likely attributable to patient-to-patient transmission. Single-strand conformation polymorphism molecular typing showed that 3 affected patients had acquired the same 2 strains of Pneumocystis, which suggests interhuman infection. An infant with mitochondriopathy was the probable index patient.