Effect of Automated Telephone Infectious Disease Consultations to Nonacademic Hospitals on 30-Day Mortality Among Patients With Staphylococcus aureus Bacteremia: The SUPPORT Cluster Randomized Clinical Trial

IMPORTANCE

Staphylococcus aureus bacteremia (SAB) is a common and potentially severe infectious disease (ID). Retrospective studies and derived meta-analyses suggest that bedside infectious disease consultation (IDC) for SAB is associated with improved survival; however, such IDCs might not always be possible because of the lack of ID specialists, particularly at nonacademic hospitals.

OBJECTIVES

To investigate whether unsolicited telephone IDCs (triggered by an automated blood stream infection reporting system) to nonacademic hospitals improved 30-day all-cause mortality in patients with SAB.

DESIGN, SETTING, AND PARTICIPANTS

This patient-blinded, multicenter, interventional, cluster randomized, controlled, crossover clinical trial was conducted in 21 rural, nonacademic hospitals in Thuringia, Germany. From July 1, 2016, to December 31, 2018, 1029 blood culture reports were assessed for eligibility. A total of 386 patients were enrolled, whereas 643 patients were not enrolled for the following reasons: death before enrollment (n = 59); palliative care (n = 41); recurrence of SAB (n = 9); discharge from the hospital before enrollment (n = 77); age younger than 18 years (n = 5); duplicate report from a single patient (n = 26); late report (n = 17); blood culture reported during the washout phase (n = 48); and no signed informed consent for other or unknown reasons (n = 361).

INTERVENTIONS

During the ID intervention phase, ID specialists from Jena University Hospital provided unsolicited telephone IDCs to physicians treating patients with SAB. During the control phase, patients were treated according to local standards. Crossover was performed after including 15 patients or, at the latest, 1 year after the first patient was included.

MAIN OUTCOMES AND MEASURES

Thirty-day all-cause mortality.

RESULTS

A total of 386 patients (median [IQR] age, 75 [63-82] years; 261 [67.6%] male) were included, with 177 randomized to the IDC group and 209 to the control group. The 30-day all-cause mortality rate did not differ between the IDC and control groups (relative risk reduction [RRR], 0.12; 95% CI, -2.17 to 0.76; P = .81). No evidence was found of a difference in secondary outcomes, including 90-day mortality (RRR, 0.17; 95% CI, -0.59 to 0.57; P = .62), 90-day recurrence (RRR, 0.10; 95% CI, -2.51 to 0.89; P = .89), and hospital readmission (RRR, 0.04; 95% CI, -0.63 to 0.48; P = .90). Exploratory evidence suggested that indicators of quality of care were potentially realized more often in the IDC group than in the control group (relative quality improvement, 0.16; 95% CI, 0.08-0.26; P = .01).

CONCLUSIONS AND RELEVANCE

In this cluster randomized clinical trial, unsolicited telephone IDC, although potentially enhancing quality of care, did not improve 30-day all-cause mortality in patients with SAB.

TRIAL REGISTRATION

drks.de Identifier: DRKS00010135.

The epidemiology of bloodstream infections and antimicrobial susceptibility patterns in Thuringia, Germany: a five-year prospective, state-wide surveillance study (AlertsNet)

Background

Monitoring pathogens of bloodstream infections (BSI) and their antibiotic susceptibility is important to guide empiric antibiotic treatment strategies and prevention programs.

This study assessed the epidemiology of BSI and antibiotic resistance patterns at the German Federal State of Thuringia longitudinally.

Methods

A surveillance network consisting of 26 hospitals was established to monitor BSIs from 01/2015 to 12/2019. All blood culture results, without restriction of age of patients, of the participating hospitals were reported by the respective microbiological laboratory. A single detection of obligate pathogens and a repeated detection of coagulase-negative staphylococci, Bacillus spp., Corynebacterium spp., Micrococcus spp. and Propionibacterium spp., within 96 h were regarded as a relevant positive blood culture. If one of the aforementioned non-obligate pathogens has been detected only once within 96 h, contamination has been assumed. Logistic regression models were applied to analyse the relationship between resistance, year of BSI and hospital size. Generalized estimating equations were used to address potential clustering.

Results

A total of 343,284 blood cultures (BC) of 82,527 patients were recorded. Overall, 2.8% (n = 9571) of all BCs were classified as contaminated. At least one relevant pathogen was identified in 13.2% (n = 45,346) of BCs. Escherichia coli (25.4%) was the most commonly detected pathogen, followed by Staphylococcus aureus (15.2%), Staphylococcus epidermidis (8.1%) and Klebsiella pneumoniae (4.6%). In S. aureus, we observed a decline of methicillin resistance (MRSA) from 10.4% in 2015 to 2.5% in 2019 (p < 0.001). The rate of vancomycin resistance in Enterococcus faecium (VRE) has increased from 16.7% in 2015 to 26.9% in 2019 (p < 0.001), with a peak in 2018 (42.5%). In addition, we observed an increase of Cefotaxime (3GC) resistance in E. coli from 10.7% in 2015 to 14.5% in 2019 (p = 0.007) whereas 3GC resistance in K. pneumoniae was stable (2015: 9.9%; 2019: 7.4%, p = 0.35). Carbapenem resistance was less than 1% for both pathogens. These patterns were robustly observed across sensitivity analyses.

Conclusions

We observed evidence for a decline in MRSA, an increase in VRE and a very low rate of carbapenem resistance in gram-negative bacteria. 3GC resistance in E. coli increased constantly over time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00997-6.

Study on the utility of a statewide counselling programme for improving mortality outcomes of patients with Staphylococcus aureus bacteraemia in Thuringia (SUPPORT): a study protocol of a cluster-randomised crossover trial

INTRODUCTION

Staphylococcus aureus bacteraemia (SAB) is a frequent infection with high mortality rates. It requires specific diagnostic and therapeutic management such as prolonged intravenous administration of antibiotics and aggressive search for and control of infectious sources. Underestimation of disease severity frequently results in delayed or inappropriate management of patients with SAB leading to increased mortality rates. According to observational studies, patient counselling by infectious disease consultants (IDC) improves survival and reduces the length of hospital stay as well as complication rates. In many countries, IDC are available only in some tertiary hospitals. In this trial, we aim to demonstrate that the outcome of patients with SAB in small and medium size hospitals that do not employ IDC can be improved by unsolicited ID phone counselling. The SUPPORT trial will be the first cluster-randomised controlled multicentre trial addressing this question.

METHODS AND ANALYSIS

SUPPORT is a single-blinded, multicentre interventional, cluster-randomised, controlled crossover trial with a minimum of 15 centres that will include 250 patients with SAB who will receive unsolicited IDC counselling and 250 who will receive standard of care. Reporting of SAB will be conducted by an electronic real-time blood culture registry established for the German Federal state of Thuringia (ALERTSNet) or directly by participating centres in order to minimise time delay before counselling. Mortality, disease course and complications will be monitored for 90 days with 30-day all-cause mortality rates as the primary outcome. Generalised linear mixed modelling will be used to detect the difference between the intervention sequences. We expect improved outcome of patients with SAB after IDC.

ETHICS AND DISSEMINATION

We obtained ethics approval from the Ethics committee of the Jena University Hospital and from the Ethics committee of the State Chamber of Physicians of Thuringia. Results will be published in a peer-reviewed journal and additionally disseminated through public media.

TRIAL REGISTRATION NUMBER

DRKS00010135.

The Thuringian registry for bloodstream infections, antibiotic resistance and the practice of blood culture sampling--AlertsNet

Evidence-based blood culture (BC) testing is of utmost importance for intensive care unit (ICU) patients suspected for sepsis. Knowledge of the aetiological agent and its susceptibility to anti-infective agents enables the clinician to initiate appropriate antimicrobial therapy and guides diagnostic procedures. This has been shown to reduce mortality, ICU stay and antibiotic overuse. Whereas microbiological laboratory practice has been highly standardised, shortfalls in pre-analytic procedures in the ICU have a significant effect on the diagnostic yield. Currently, surveillance data on BC practice lack hospital-, patient- and laboratory-based denominator data. Supporting information on differences in the clinical practice of BC testing, differences in the characteristics of the institution and the case-mix on specific wards, as well as differences in the availability of microbiological laboratories is demanded on a population basis. A population-based survey on BC practice has been established for the German Federal State of Thuringia connecting both hospitals and microbiological laboratories within an electronic registry for immediate enrolment of BC findings (AlertsNet; http://www.alertsnet.de). The registry includes microbiological results and clinical data as well as institutional variables (e.g. case severity indices) from all patients with clinically relevant positive BCs at the participating centres. The main objectives are to sustain and expand a population-based surveillance and warning system for the assessment of diagnosis, risk factors, treatment and outcomes of hospitalised patients and to improve outcomes of patients with bloodstream infections.

Quality of blood culture testing - a survey in intensive care units and microbiological laboratories across four European countries

Introduction

Blood culture (BC) testing before initiation of antimicrobial therapy is recommended as a standard of care in international sepsis guidelines and has been shown to reduce intensive care unit (ICU) stay, antibiotic use, and costs in hospitalized patients. Whereas microbiological laboratory practice has been highly standardized, shortfalls in the preanalytic procedures in the ICU (that is indication, time-to-incubation, blood volume and numbers of BC sets) have a significant effect on the diagnostic yield. The objective of this study was to gain insights into current practices regarding BC testing in intensive care units.

Methods

Qualitative survey, data collection by 138 semi-structured telephone interviews in four European countries (Italy, UK, France and Germany) between September and November 2009 in 79 clinical microbiology laboratories (LABs) and 59 ICUs.

Results

Whereas BC testing is expected to remain the gold standard for sepsis diagnostics in all countries, there are substantial differences regarding preanalytic procedures. The decision to launch BC testing is carried out by physicians vs. ICU nurses in the UK in 92 vs. 8%, in France in 75 vs. 25%, in Italy in 88 vs. 12% and in Germany in 92 vs. 8%. Physicians vs. nurses collect BCs in the UK in 77 vs. 23%, in France in 0 vs. 100%, in Italy in 6 vs. 94% and in Germany in 54 vs. 46%. The mean time from blood collection to incubation in the UK is 2 h, in France 3 h, in Italy 4 h, but 20 h in German remote LABs (2 h in in-house LABs), due to the large number of remote nonresident microbiological laboratories in Germany. There were major differences between the perception of the quality of BC testing between ICUs and LABs. Among German ICU respondents, 62% reported that they have no problems with BC testing, 15% reported time constraints, 15% cost pressure, and only 8% too long time to incubation. However, the corresponding LABs of these German ICUs reported too many false positive results due to preanalytical contaminations (49%), insufficient numbers of incoming BC sets (47%), long transportation time (41%) or cost pressure (18%).

Conclusions

There are considerable differences in the quality of BC testing across European countries. In Germany, time to incubation is a considerable problem due to the increasing number of remote LABs. This is a major issue of concern to physicians aiming to implement sepsis guidelines in the ICUs.

Evidence for a radical mechanism of the dechlorination of chlorinated propenes mediated by the tetrachloroethene reductive dehalogenase of Sulfurospirillum muftivorans

The reductive dehalogenation of chlorinated propenes was studied with the tetrachloroethene reductive dehalogenase purified from Sulfurospirillum multivorans to obtain indications for a radical mechanism of this reaction. When reduced methyl viologen (MV), which is a radical cation, was applied as electron donor for the reduction of different chloropropenes, a significant part of MV could not be rereduced with Ti(III) citrate, indicating that a part of the MV was consumed in a side reaction. Mass spectrometric analysis of assays with MV as electron donor revealed the formation of side products, the masses of which might account for the formation of adducts from a chloropropenyl radical and reduced methyl viologen. With Ti(III) citrate as sole electron donor, 2,3-dichloropropene was reduced and as a side product, 2,5-dichloro-1,5-hexadiene was formed demonstrating that the reductive dechlorination of 2,3-dichloropropene proceeds via a radical reaction mechanism. The results support different dehalogenation mechanisms forthe reductive dechlorination of chloropropenes and halogenated ethenes.

Growth substrate dependent localization of tetrachloroethene reductive dehalogenase in Sulfurospirillum multivorans

Sulfurospirillum multivorans is a dehalorespiring organism, which is able to utilize tetrachloroethene as terminal electron acceptor in an anaerobic respiratory chain. The localization of the tetrachloroethene reductive dehalogenase in dependence on different growth substrates was studied using the freeze-fracture replica immunogold labeling technique. When the cells were grown with pyruvate plus fumarate, a major part of the enzyme was either localized in the cytoplasm or membrane associated facing the cytoplasm. In cells grown on pyruvate or formate as electron donors and tetrachloroethene as electron acceptor, most of the enzyme was detected at the periplasmic side of the cytoplasmic membrane. These results were confirmed by immunoblots of the enzyme with and without the twin arginine leader peptide. Trichloroethene exhibited the same effect on the enzyme localization as tetrachloroethene. The data indicated that the localization of the enzyme was dependent on the electron acceptor utilized.

The operon of

The complete single copy fdh operon (approximately 5.7 kb) encoding the formate dehydrogenase subunits of the gram negative, reductively dehalogenating anaerobe Sulfurospirillum multivorans was sequenced and analyzed. The gene fdhA encoding the catalytically active periplasmic subunit is part of an operon (fdhEABCD) containing additional structural genes. The genes fdhEABCD were cotranscribed as indicated by RT-PCR and primer extension experiments. Two mRNAs for fdhEABCD and fdhABCD were either transcribed independently from two transcription start sites upstream of fdhE and fdhA or might result from posttranscriptional processing of the full-length fdhEABCD mRNA. The operon shows a high degree of similarity to the fdh operons of Campylobacter jejuni and Wolinella succinogenes in terms of architecture and putative cofactor binding motifs of the gene products.

Purification and properties of the formate dehydrogenase and characterization of the fdhA gene of Sulfurospirillum multivorans

The soluble periplasmic subunit of the formate dehydrogenase FdhA of the tetrachloroethene-reducing anaerobe Sulfurospirillum multivorans was purified to apparent homogeneity and the gene ( fdhA) was identified and sequenced. The purified enzyme catalyzed the oxidation of formate with oxidized methyl viologen as electron acceptor at a specific activity of 1683 nkat/mg protein. The apparent molecular mass of the native enzyme was determined by gel filtration to be about 100 kDa, which was confirmed by the fdhA nucleotide sequence. fdhA encodes for a pre-protein that differs from the truncated mature protein by an N-terminal 35-amino-acid signal peptide containing a twin arginine motif. The amino acid sequence of FdhA revealed high sequence similarities to the larger subunits of the formate dehydrogenases of Campylobacter jejuni, Wolinella succinogenes, Escherichia coli (FdhN, FdhH, FdhO), and Methanobacterium formicicum. According to the nucleotide sequence, FdhA harbors one Fe(4)/S(4) cluster and a selenocysteine residue as well as conserved amino acids thought to be involved in the binding of a molybdopterin guanidine dinucleotide cofactor.