Presence of hypervirulence-associated determinants in Klebsiella pneumoniae from hospitalised patients in Germany

BACKGROUND

Klebsiella (K.) pneumoniae is a ubiquitous Gram-negative bacterium and a common coloniser of animals and humans. Today, K. pneumoniae is one of the most persistent nosocomial pathogens worldwide and poses a severe threat/burden to public health by causing urinary tract infections, pneumonia and bloodstream infections. Infections mainly affect immunocompromised individuals and hospitalised patients. In recent years, a new type of K. pneumoniae has emerged associated with community-acquired infections such as pyogenic liver abscess in otherwise healthy individuals and is therefore termed hypervirulent K. pneumoniae (hvKp). The aim of this study was the characterisation of K. pneumoniae isolates with properties of hypervirulence from Germany.

METHODS

A set of 62 potentially hypervirulent K. pneumoniae isolates from human patients was compiled. Inclusion criteria were the presence of at least one determinant that has been previously associated with hypervirulence: (I) clinical manifestation, (II) a positive string test as a marker for hypermucoviscosity, and (III) presence of virulence associated genes rmpA and/or rmpA2 and/or magA. Phenotypic characterisation of the isolates included antimicrobial resistance testing by broth microdilution. Whole genome sequencing (WGS) was performed using Illumina® MiSeq/NextSeq to investigate the genetic repertoire such as multi-locus sequence types (ST), capsule types (K), further virulence associated genes and resistance genes of the collected isolates. For selected isolates long-read sequencing was applied and plasmid sequences with resistance and virulence determinants were compared.

RESULTS

WGS analyses confirmed presence of several signature genes for hvKp. Among them, the most prevalent were the siderophore loci iuc and ybt and the capsule regulator genes rmpA and rmpA2. The most dominant ST among the hvKp isolates were ST395 capsule type K2 and ST395 capsule type K5; both have been described previously and were confirmed by our data as multidrug-resistant (MDR) isolates. ST23 capsule type K1 was the second most abundant ST in this study; this ST has been described as commonly associated with hypervirulence. In general, resistance to beta-lactams caused by the production of extended-spectrum beta-lactamases (ESBL) and carbapenemases was observed frequently in our isolates, confirming the threatening rise of MDR-hvKp strains.

CONCLUSIONS

Our study results show that K. pneumoniae strains that carry several determinants of hypervirulence are present for many years in Germany. The detection of carbapenemase genes and hypervirulence associated genes on the same plasmid is highly problematic and requires intensified screening and molecular surveillance. However, the non-uniform definition of hvKp complicates their detection. Testing for hypermucoviscosity alone is not specific enough to identify hvKp. Thus, we suggest that the classification of hvKp should be applied to isolates that not only fulfil phenotypical criteria (severe clinical manifestations, hypermucoviscosity) but also (I) the presence of at least two virulence loci e.g. iuc and ybt, and (II) the presence of rmpA and/or rmpA2.

Improving leadership skills of infection prevention and control teams by psychological empowerment: study protocol for a cluster randomised controlled trial (IP-POWER)

INTRODUCTION

Infection prevention and control (IPC) teams are routinely confronted with intense emotions in their daily work, as they are involved in many change processes with front-line medical staff, for example, when promoting compliance with basic IPC measures. In addition, they are confronted with challenges due to their role as intermediaries. Based on former research, this study aims to empower IPC teams to promote clinicians' compliance through interventions focusing on the IPC teams' leadership skills.

METHODS AND ANALYSIS

The IP-POWER study (Infection Prevention with head and heart: Psychological empowerment of IPC teams), a multicentre, two-arm, non-blinded, cluster-randomised controlled trial with a parallel waiting control group, is planned to be conducted in Germany as of February to November 2024. A group of 10 voluntary hospitals is going to participate in a multistage intervention programme, including 2 days of intense psychological training; 5 hospitals will be randomly assigned to the waiting control group. After the workshops, there will be a 12-week follow-up period during which the contents learnt within the workshops can be applied and internalised into IPC practice. The proposed outcomes (both self-assessed and other-assessed leadership competencies of IPC team members and their task profiles, perceived workload, motivation to act in order to implement IP measures and goal attainment) are going to be collected with an online questionnaire, followed by an analysis with IBM SPSS (Statistics 29 (or later)) using descriptive analyses and multiple linear regressions. Additionally, as external data sources, hand hygiene compliance rates from the study hospitals' monitoring systems will be analysed using χ² tests.

ETHICS AND DISSEMINATION

This study was reviewed and approved by the ethics committee of the University of Leipzig (184/23-ek; vote from 4 July 2023). Findings will be disseminated via peer-review publications, and national and international conference presentations.

TRIAL REGISTRATION NUMBER

DRKS00031879.

Rectal colonization is predictive for surgical site infections with multidrug-resistant bacteria in abdominal surgery

PURPOSE

Superficial surgical site infections (SSI) are a common complication after abdominal surgery. Additionally, multidrug-resistant organisms (MDRO) have shown an increasing spread in recent years with a growing importance for health care. As there is varying evidence on the importance of MDRO in different surgical fields and countries as causative agents of SSI, we report our findings of MDRO-caused SSI.

METHODS

We assembled an institutional wound register spanning the years 2015-2018 including all patients with abdominal surgery and SSI only, including demographics, procedure-related data, microbiological data from screenings, and body fluid samples. The cohort was examined for the frequency of different MDRO in screenings, body fluids, and wound swabs and assessed for risk factors for MDRO-positive SSI.

RESULTS

A total of 138 out of 494 patients in the register were positive for MDRO, and of those, 61 had an MDRO isolated from their wound, mainly multidrug-resistant Enterobacterales (58.1%) followed by vancomycin-resistant Enterococcus spp. (19.7%). As 73.2% of all MDRO-carrying patients had positive rectal swabs, rectal colonization could be identified as the main risk factor for an SSI caused by a MDRO with an odds ratio (OR) of 4.407 (95% CI 1.782-10.896, p = 0.001). Secondly, a postoperative ICU stay was also associated with an MDRO-positive SSI (OR 3.73; 95% CI 1.397-9.982; p = 0.009).

CONCLUSION

The rectal colonization status with MDRO should be taken into account in abdominal surgery regarding SSI prevention strategies. Trial registration Retrospectively registered in the German register for clinical trials (DRKS) 19th December 2019, registration number DRKS00019058.

[Resource conservation from the perspective of infection prevention]

BACKGROUND

Procedures to prevent surgical site infections require a high input of human, technical and natural resources. This paper explores ways to optimize the use of resources in caring for patients who undergo a surgical procedure without compromising patient safety.

METHODS

Review of the contribution of selected procedures for infection prevention in surgical patients considering current evidence and recommendations by comparing current guidelines and results of clinical trials. Analysis of interventions to implement and increase compliance.

RESULTS

Knowledge of current evidence-based recommendations enables not only the identification of procedures with proven effect on infection prevention but also those that are ineffective and thus dispensable. There is still need for further controlled studies, e.g. on the use of antiseptics, that can confirm the evidence level of preventive procedures. Infection surveillance in combination with process and compliance monitoring by infection prevention specialists with a feedback system to healthcare workers are suitable control instruments for infection control management. In the case of increased infection rates, the implementation of evidence-based recommended measures through tailored bundle interventions is successful. Technical measures to maintain environmental conditions must be included in the control process.

CONCLUSION

The reduction of healthcare-associated infections by implementing tailored interventions of infection prevention measures and elimination of ineffective procedures conserves resources and promotes patient safety.

Compliance assessment regarding the PVC management on normal wards of a university hospital

Objective

The risk of peripheral venous catheter (PVC) infections in inpatients is often underestimated, even if it is lower than that for central venous catheters. Guidelines for the prevention of PVC-associated infections describe the evidence-based management of PVCs. The aims of this study were the development of standardized methods for compliance assessment regarding PVC management and the evaluation of self-reported knowledge and implementations among healthcare providers regarding PVC care.

Method

We developed a checklist based on the recommendation of the Commission of Hospital Hygiene and Infection Prevention at the Robert Koch Institute (KRINKO) Berlin for the standardized evaluation of PVC management. The following parameters were collected and evaluated: condition of the puncture site, condition of the bandage, presence of an extension set, presence of a plug, and documentation. The checklist was applied in 14 normal wards in 2019. After feedback of the ward staff on the results, it was applied again in 2020 in the same wards. For retrospective data analysis, we used a newly developed PVC-quality index. After the second evaluation in 2020, we carried out an anonymous survey among the healthcare providers.

Results

The evaluation of 627 indwelling PVCs showed a significant increase in compliance related to the presence of an extension set (p=0.049) and documentation (p<0.001) in the 2nd year. The quality index increased in 12 out of 14 wards. The participants of the survey were aware of the in-house standard "Prevention of vascular catheter-associated infections", with a mean score of 4.98 on a Likert scale (1=not aware, 7=completely aware). The main barrier to implementation of the preventive measures was the time factor. Survey participants were more aware of PVC placement than PVC care.

Conclusion

The PVC quality index is a valuable tool for the assessment of compliance regarding PVC management in daily practice. Feedback from the ward staff on the results of compliance assessment improves PVC management, but the outcome is very heterogeneous.

Best practice approaches to outpatient management of people living with Parkinson's disease during the COVID-19 pandemic

The prevalence of Parkinson’s disease (PD) is rising, rendering it one of the most common neurodegenerative diseases. Treatment and monitoring of patients require regular specialized in- and outpatient care. Patients with PD are more likely to have a complicated disease course if they become infected with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Regular in-hospital appointments place these patients at risk of exposure to SARS-CoV-2 due to travel and contact with other patients and staff. However, guidelines for the management of outpatients with PD during times of increased risk of infection are currently lacking. These are urgently needed to conduct risk–benefit evaluations to recommend the best medical treatment. This article discusses best practice approaches based on the current literature, as suggested by the multidisciplinary Network of University Medicine (NUM) in Germany. These include measures such as mask-wearing, hand hygiene, social distancing measures, and appropriate testing strategies in outpatient settings, which can minimize the risk of exposure. Furthermore, the urgency of appointments should be considered. Visits of low urgency may be conducted by general practitioners or via telemedicine consultations, whereas in-person presentation is required in case of moderate and high urgency visits. Classification of urgency should be carried out by skilled medical staff, and telemedicine (telephone or video consultations) may be a useful tool in this situation. The currently approved vaccines against SARS-CoV-2 are safe and effective for patients with PD and play a key role in minimizing infection risk for patients with PD.

Tailoring implementation interventions of different order in infection prevention and control: A cascadic logic model (IPC-CASCADE)

Implementation interventions in infection prevention and control (IPC) differ by recipients. The two target groups are healthcare workers directly involved in patient care ("frontline") and IPC professionals as proxy agents, that is, implementation support practitioners. While both types of implementation interventions aim to promote compliance with clinical interventions to prevent healthcare-associated infections (HAI), their tailoring may be vastly different, for example, due to different behavioural outcomes. Additionally, IPC teams, as recipients of empowering tailored interventions, are under-researched. To overcome this gap and improve conceptual clarity, we proposed a cascadic logic model for tailored IPC interventions (IPC-CASCADE). In the model, we distinguished between interventions by IPC professionals targeting clinicians and those targeting IPC professionals (first- and second-order implementation interventions, respectively). Tailoring implies selecting behaviour change techniques matched to prospectively-assessed determinants of either clinician compliance (in first-order interventions) or interventions by IPC professionals for frontline workers (in second-order interventions). This interventional cascade is embedded in the prevailing healthcare system. IPC-CASCADE is horizontally structured over time and vertically structured by hierarchy or leadership roles. IPC-CASCADE aims to highlight the potential of increasing the impact of tailored interventions by IPC professionals for clinicians (to improve their compliance) via tailored interventions for IPC professionals (to improve their work as proxy agents). It underlines the links that IPC professionals define between macro contexts (healthcare and hospitals) and frontline workers in HAI prevention. It is specific, i.e., "tailored" to IPC, and expected to assist implementation science to better conceptualise tailoring.

Characterization of SARS-CoV-2 infection clusters based on integrated genomic surveillance, outbreak analysis and contact tracing in an urban setting

Background

Tracing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission chains is still a major challenge for public health authorities, when incidental contacts are not recalled or are not perceived as potential risk contacts. Viral sequencing can address key questions about SARS-CoV-2 evolution and may support reconstruction of viral transmission networks by integration of molecular epidemiology into classical contact tracing.

Methods

In collaboration with local public health authorities, we set up an integrated system of genomic surveillance in an urban setting, combining a) viral surveillance sequencing, b) genetically based identification of infection clusters in the population, c) integration of public health authority contact tracing data, and d) a user-friendly dashboard application as a central data analysis platform.

Results

Application of the integrated system from August to December 2020 enabled a characterization of viral population structure, analysis of 4 outbreaks at a maximum care hospital, and genetically based identification of 5 putative population infection clusters, all of which were confirmed by contact tracing. The system contributed to the development of improved hospital infection control and prevention measures and enabled the identification of previously unrecognized transmission chains, involving a martial arts gym and establishing a link between the hospital to the local population.

Conclusions

Integrated systems of genomic surveillance could contribute to the monitoring and, potentially, improved management of SARS-CoV-2 transmission in the population.

Long-Term, Low-Frequency Cluster of a German-Imipenemase-1-Producing Enterobacter hormaechei ssp. steigerwaltii ST89 in a Tertiary Care Hospital in Germany

Enterobacter cloacae complex is a common cause of hospital outbreaks. A retrospective and prospective molecular analysis of carbapenem-resistant clinical isolates in a tertiary care center demonstrated an outbreak of a German-imipenemase-1 (GIM-1) metallo-beta-lactamase-producing Enterobacter hormaechei ssp. steigerwaltii affecting 23 patients between 2009 and 2016. Thirty-three isolates were sequence type 89 by conventional multilocus sequence typing (MLST) and displayed a maximum difference of 49 out of 3,643 targets in the ad-hoc core-genome MLST (cgMLST) scheme (SeqSphere+ software; Ridom, Münster, Germany). The relatedness of all isolates was confirmed by further maximum-likelihood phylogeny. One clonal complex of highly related isolates (≤15 allele difference in cgMLST) contained 17 patients, but epidemiological data only suggested five transmission events. The bla_GIM-1-gene was embedded in a class-1-integron (In770) and the Tn21-subgroup transposon Tn6216 (KC511628) on a 25-kb plasmid. Environmental screening detected one colonized sink trap in a service room. The outbreak was self-limited as no further bla_GIM-1-positive E. hormaechei has been isolated since 2016. Routine molecular screening of carbapenem-nonsusceptible gram-negative isolates detected a long-term, low-frequency outbreak of a GIM-1-producing E. hormaechei ssp. steigerwaltii clone. This highlights the necessity of molecular surveillance.

Quantitative bedside testing of troponin T: is it equal to laboratory testing? The Cardiac Reader Troponin T (CARE T) study

The progressive evolution of cardiac marker testing in patients with acute coronary syndromes has extended their role into risk stratification and guidance of therapeutic regimen. To provide utilization of cardiac markers around the clock and facilitate the diagnostic work-up of patients with acute chest pain in the emergency room, a point-of-care system for quantitative troponin T and myoglobin testing in whole blood samples was developed. Aim of this multicenter study was to evaluate bedside quantitative determination of myoglobin and troponin T in chest pain patients in a clinical routine setting. Five hospitals in Germany were contributing to blood sampling and 741 patients were included four hours (median) after onset of cardiac pain. Comparison between the rapid test and the established laboratory-based method showed a sufficient agreement of results with a correlation of r = 0.89 (Y = 0.856x + 0.029) for troponin T and r = 0.912 (Y= +1.145x + 3.457) for myoglobin. Diagnostic sensitivity and prognostic power of the troponin T results obtained in the emergency unit were thoroughly equivalent to the laboratory-based method. The results show that the cardiac reader system represents a promising alternative to central laboratory testing with an accuracy sufficiently for rapid decision making in the emergency room. Myoglobin results in this study did not add supplementary information to the cardiac reader troponin result. However, point-of-care testing of troponin T is advantageous whenever marker results could positively effect initial triage decisions and interventional management choices.

Multicenter evaluation of a fully mechanized soluble transferrin receptor assay on the Hitachi and cobas integra analyzers. the determination of reference ranges

Soluble transferrin receptor (sTfR) is reported to be a reliable marker for the diagnosis of iron deficiency, especially when iron metabolism is influenced by inflammatory disorders such as infection, chronic inflammation and cancer-related anemia. In the present multicenter study the analytical performance of a recently introduced, latex-enhanced immunoturbidimetric assay for the determination of soluble transferrin receptor (Tina quant [a] sTfR, Roche Diagnostics) on different fully mechanized analyzers such as Hitachi 917 and 911, and Cobas Integra 400 and 700 was evaluated. Within-run and between-run imprecision showed good results (CV<5% and <7%, respectively). The assay was found to be linear over a wide measuring range (0.4-35 mg/l). Endogenous substances did not interfere with the test results. Comparison of serum sTfR concentrations with those of heparinized plasma revealed good correlation (r>0.976). Method comparison with an existing fully mechanized method as well as with ELISA tests for sTfR showed very good correlation (r>0.987). Because of the lack of international standardization the results differed from each other up to 2.5-fold. The 95% of serum levels in healthy individuals ranged from 1.9 to 4.4 mg/l (n=427). However, the reference ranges should be reported in a sex-dependent manner, as 2.2-5.0 mg/l for men (n=211) and as 1.9-4.4 mg/l for premenopausal (n=216) and postmenopausal (n=45) women. The Tina quant [a] sTfR assay enables the precise, accurate, rapid and convenient determination of sTfR concentrations for routine clinical chemistry purposes.

A novel keratan sulphate domain preferentially expressed on the large aggregating proteoglycan from human articular cartilage is recognized by the monoclonal antibody 3D12/H7

Monoclonal antibodies (mAbs) were prepared against aggrecan which has been isolated from human articular cartilage and purified by several chromatographic steps. One of these mAbs, the aggrecan-specific mAb 3D12/H7, was selected for further characterization. The data presented indicate that this mAb recognizes a novel domain of keratan sulphate chains from aggrecan: (1) immunochemical staining of aggrecan is abolished by treatment with keratanase/keratanase II, but not with keratanase or chondroitin sulphate lyase AC/ABC; (2) after chemical deglycosylation of aggrecan no staining of the core-protein was observed; (3) different immunochemical reactivity was observed against keratan sulphates from articular cartilage, intervertebral disc and cornea for the mAbs 3D12/H7 and 5D4. For further characterization of the epitope, reduced and 3H-labelled keratan sulphate chains were prepared. In an IEF-gel-shift assay it was shown that the 3H-labelled oligosaccharides obtained after keratanase digestion of reduced and 3H-labelled keratan sulphate chains were recognized by the mAb 3D12/H7. Thus it can be concluded that the mAb 3D12/H7 recognizes an epitope in the linkage region present in, at least some, keratan sulphate chains of the large aggregating proteoglycan from human articular cartilage. Moreover, this domain seems to be expressed preferentially on those keratan sulphate chains which occur in the chondroitin sulphate-rich region of aggrecan, since the antibody does not recognize the keratan sulphate-rich region obtained after combined chondroitinase AC/ABC and trypsin digestion of aggrecan.

Development of enzyme immunoassays specific for keratan sulphate- and core-protein-epitopes of the large aggregating proteoglycan from human articular cartilage

In the course of chronic inflammatory and degenerative joint diseases proteoglycans are degraded by the action of proteases and oxygen radicals. Therefore, proteoglycan fragments, released from cartilage into the peripheral blood, might be useful markers of cartilage degradation. Sensitive enzyme immunoassays are useful for the detection of these proteoglycan fragments in serum. We therefore developed specific monoclonal antibodies against the large aggregating proteoglycan (aggrecan), which has been isolated and purified from human articular cartilage. Two monoclonal antibodies which recognize a novel cartilage-specific epitope on the keratan sulphate chain of aggrecan (mAb 4B3/D10) and an epitope of the core-protein of aggrecan (4G4/A10) were selected for the development of competitive enzyme-immunoassays. These assays allow the sensitive and specific detection of cartilage-derived proteoglycan fragments, not only in synovial fluid but also in serum. They can now be used for the study of inflammatory and degenerative joint diseases.