Association between vancomycin-resistant Enterococci bacteremia and ceftriaxone usage

Improving antimicrobial treatment in terms of antimicrobial stewardship and health costs by an OPAT service

PURPOSE

Outpatient parenteral antimicrobial therapy (OPAT) is a standard for antimicrobial therapy internationally. With this prospective cohort study, we aimed to assess the impact of an OPAT service as part of antimicrobial stewardship (AMS) and evaluate the safety and efficiency of the program while illuminating the financial benefit for the hospital.

METHODS

Socio-demographic data, treatment regimen and outcomes were prospectively recorded for all patients assigned to the program of the OPAT unit of the University Hospital of Zurich between November 2018 and September 2022.

RESULTS

In total, we recorded 303 OPAT assignments of which 260 resulted in effective OPAT episodes. The 260 OPAT episodes were further optimized toward the choice of antimicrobial agent (n = 18) and length of therapy (n = 6). Moreover, OPAT resulted in alteration of patient assessment and care led by AMS strategies in 247 of 260 episodes (95%). While the bed days saved per year increased consistently with time, a total of 3934 in-hospital treatment days were saved amounting to a cost saving of 9,835,000 CHF over 47 months. Adverse events were recorded in 46 cases whilst only two of these have been the reason for readmission during OPAT treatment. Clinical cure was noted in 77% (199/260) and was negatively associated with Charlson Comorbidity Index (CCI; OR per 1 unit higher 0.85 (95% CI 0.78-0.93)).

CONCLUSION

This study demonstrates the impact of an OPAT service in the framework of AMS as well as its benefits for the hospital whilst preserving safety and efficacy for the patient's parenteral antimicrobial treatment.

Antibiotic use in pediatric acute care hospitals: an analysis of antibiotic consumption data from Germany, 2013-2020

BACKGROUND

Antimicrobial stewardship (AMS) programs are effective tools for improving antibiotic prescription quality. Their implementation requires the regular surveillance of antibiotic consumption at the patient and institutional level. Our study captured and analyzed antibiotic consumption density (ACD) for hospitalized pediatric patients.

METHOD

We collected antibacterial drug consumption data for 2020 from hospital pharmacies at 113 pediatric departments of acute care hospitals in Germany. ACD was calculated as defined daily dose (DDD, WHO/ATC Index 2019) per 100 patient days (pd). In addition, we analyzed the trends in antibiotic use during 2013-2020.

RESULTS

In 2020, median ACD across all participating hospitals was 26.7 DDD/100 pd, (range: 10.1-79.2 DDD/100 pd). It was higher at university vs. non-university hospitals (38.6 vs. 25.2 DDD/100 pd, p < 0.0001). The highest use densities were seen on oncology wards and intensive care units at university hospitals (67.3 vs. 38.4 DDD/100 pd). During 2013-2020, overall ACD declined (- 10%) and cephalosporin prescriptions also decreased (- 36%). In 2020, cephalosporins nevertheless remained the most commonly dispensed class of antibiotics. Interhospital variability in cephalosporin/penicillin ratio was substantial. Antibiotics belonging to WHO AWaRe "Watch" and "Reserve" categories, including broad-spectrum penicillins (+ 31%), linezolid (+ 121%), and glycopeptides (+ 43%), increased over time.

CONCLUSION

Significant heterogeneity in ACD and prescription of different antibiotic classes as well as high prescription rates for cephalosporins and an increased use of reserve antibiotics indicate improvable antibiotic prescribing quality. AMS programs should urgently prioritize these issues to reduce antimicrobial resistance.

Promiscuous, persistent and problematic: insights into current enterococcal genomics to guide therapeutic strategy

Vancomycin-resistant enterococci (VRE) are major opportunistic pathogens and the causative agents of serious diseases, such as urinary tract infections and endocarditis. VRE strains mainly include species of Enterococcus faecium and E. faecalis which can colonise the gastrointestinal tract (GIT) of patients and, following growth and persistence in the gut, can transfer to blood resulting in systemic dissemination in the body. Advancements in genomics have revealed that hospital-associated VRE strains are characterised by increased numbers of mobile genetic elements, higher numbers of antibiotic resistance genes and often lack active CRISPR-Cas systems. Additionally, comparative genomics have increased our understanding of dissemination routes among patients and healthcare workers. Since the efficiency of currently available antibiotics is rapidly declining, new measures to control infection and dissemination of these persistent pathogens are urgently needed. These approaches include combinatory administration of antibiotics, strengthening colonisation resistance of the gut microbiota to reduce VRE proliferation through commensals or probiotic bacteria, or switching to non-antibiotic bacterial killers, such as bacteriophages or bacteriocins. In this review, we discuss the current knowledge of the genomics of VRE isolates and state-of-the-art therapeutic advances against VRE infections.

Hub and Spoke: Next level in regional networks for infection prevention

The threat of multidrug-resistant organisms (MDROs) and antimicrobial resistance (AMR) are real and increasing every day. They affect not only healthcare systems but also communities, causing economic and public health concerns. Governments must take action to tackle AMR and prevent the spread of MDROs and regional hubs have a critical role to play in achieving this outcome. Furthermore, bacteria have no borders, consequently, cooperation networks should be extended between countries as a crucial strategy for achieving the success of infection control. Euregions, which are a specific form of cooperation between local authorities of two or more bordering European countries, can help solve common problems and improve the lives of people living on both sides of the border. Regional collaboration strategies can enhance infection control and build resilience against antimicrobial resistance. This review identifies risk factors and the correct approaches to infection prevention and control, including education and awareness programs for healthcare professionals, appropriate prescribing practices, and infection prevention control measures. These measures can help reduce the incidence of antimicrobial resistance in the region and save lives. It is therefore essential to take concrete actions and foster the creation of more effective regional and cross-border centers to ensure the success of infection control policies and the management of healthcare-associated infections. This work sheds light on the issue of MDRO infections within healthcare settings, while also acknowledging the crucial role of the One Health concept in understanding the broader context of these infections. By recognizing the interdependence of human and animal health and the environment, we can take constructive steps toward mitigating the risks of these infections and promoting better health outcomes for all.

Adaptation and validation of a quantitative vanA/vanB DNA screening assay on a high-throughput PCR system

Vancomycin resistant enterococci (VRE) are a leading cause of ICU-acquired bloodstream infections in Europe. The bacterial load in enteral colonization may be associated with a higher probability of transmission. Here, we aimed to establish a quantitative vanA/vanB DNA real-time PCR assay on a high-throughput system. Limits of detection (LOD), linear range and precision were determined using serial bacterial dilutions. LOD was 46.9 digital copies (dcp)/ml for vanA and 60.8 dcp/ml for vanB. The assay showed excellent linearity between 4.7 × 101 and 3.5 × 105 dcp/ml (vanA) and 6.7 × 102 and 6.7 × 105 dcp/ml (vanB). Sensitivity was 100% for vanA and vanB, with high positive predictive value (PPV) for vanA (100%), but lower PPV for vanB (34.6%) likely due to the presence of vanB DNA positive anerobic bacteria in rectal swabs. Using the assay on enriched VRE broth vanB PPV increased to 87.2%. Quantification revealed median 2.0 × 104 dcp/ml in PCR positive but VRE culture negative samples and median 9.1 × 104 dcp/ml in VRE culture positive patients (maximum: 107 dcp/ml). The automated vanA/B_UTC assay can be used for vanA/vanB detection and quantification in different diagnostic settings and may support future clinical studies assessing the impact of bacterial load on risk of infection and transmission.

Characterization of a Tigecycline-, Linezolid- and Vancomycin-Resistant Clinical Enteroccoccus faecium Isolate, Carrying vanA and vanB Genes

INTRODUCTION

Increasing incidence of Enterococcus faecium resistant to key antimicrobials used in therapy of hospitalized patients is a worrisome phenomenon observed worldwide. Our aim was to characterize a tigecycline-, linezolid- and vancomycin-resistant E. faecium isolate with the vanA and vanB genes, originating from a hematoma of a patient hospitalized in an intensive care unit in Poland.

METHODS

Antimicrobial susceptibility (a broad panel) was tested using gradient tests with predefined antibiotic concentrations. The complete genome sequence was obtained from a mixed assembly of Illumina MiSeq and Oxford Nanopore's MinION reads. The genome was analyzed with appropriate tools available at the Center for Genomic Epidemiology, PubMLST and GenBank. Transferability of oxazolidinone, tigecycline and vancomycin resistance genes was investigated by conjugation, followed by PCR screen of transconjugants for antimicrobial resistance genes and plasmid rep genes characteristic for the donor and genomic sequencing of selected transconjugants.

RESULTS

The isolate was resistant to most antimicrobials tested; susceptibility to daptomycin, erythromycin and chloramphenicol was significantly reduced, and only oritavancin retained the full activity. The isolate represented sequence type 18 (ST18) and carried vanA, vanB, poxtA, fexB, tet(L), tet(M), aac(6')-aph(2''), ant(6)-Ia and ant(6')-Ii. The vanA, poxtA and tet(M) genes located on ~ 40-kb plasmids were transferable by conjugation yielding transconjugants resistant to vancomycin, linezolid and tigecycline. The substitutions in LiaS, putative histidine kinase, SulP, putative sulfate transporter, RpoB and RpoC were potential determinants of an elevated daptomycin MIC. Comparative analyses of the studied isolate with E. faecium isolates from other countries revealed its similarity to ST18 isolates from Ireland and Uganda from human infections.

CONCLUSIONS

We provide the detailed characteristics of the genomic determinants of antimicrobial resistance of a clinical E. faecium demonstrating the concomitant presence of both vanA and vanB and resistance to vancomycin, linezolid, tigecycline and several other compounds and decreased daptomycin susceptibility. This isolate is a striking example of an accumulation of resistance determinants involving various mechanisms by a single hospital strain.

Vancomycin-resistant enterococci (VRE) in hospital settings across European borders: a scoping review comparing the epidemiology in the Netherlands and Germany

The rising prevalence of vancomycin-resistant enterococci (VRE) is a matter of concern in hospital settings across Europe without a distinct geographical pattern. In this scoping review, we compared the epidemiology of vancomycin-resistant Enterococcus spp. in hospitals in the Netherlands and Germany, between 1991 and 2022. We searched PubMed and summarized the national antibiotic resistance surveillance data of the two countries. We included 46 studies and summarized national surveillance data from the NethMap in the Netherlands, the National Antimicrobial Resistance Surveillance database in Germany, and the EARS-Net data. In total, 12 studies were conducted in hospitals in the Netherlands, 32 were conducted in German hospitals, and an additional two studies were conducted in a cross-border setting. The most significant difference between the two countries was that studies in Germany showed an increasing trend in the prevalence of VRE in hospitals, and no such trend was observed in studies in the Netherlands. Furthermore, in both Dutch and German hospitals, it has been revealed that the molecular epidemiology of VREfm has shifted from a predominance of vanA towards vanB over the years. According to national surveillance reports, vancomycin resistance in Enterococcus faecium clinical isolates fluctuates below 1% in Dutch hospitals, whereas it follows an increasing trend in German hospitals (above 20%), as supported by individual studies. This review demonstrates that VRE is more frequently encountered in German than in Dutch hospitals and discusses the underlying factors for the difference in VRE occurrence in these two neighboring countries by comparing differences in healthcare systems, infection prevention control (IPC) guidelines, and antibiotic use in the Netherlands and Germany.

Previous antibiotic therapy as independent risk factor for the presence of vancomycin-resistant enterococci in surgical inpatients. Results from a matched case-control study

BACKGROUND

Investigation of risk factors for the presence of vancomycin-resistant enterococci (VRE) in inpatients on surgical wards and associated intensive care units of a German tertiary care hospital.

METHODS

A single-centre retrospective matched case-control study was performed with surgical inpatients admitted between July 2013 and December 2016. Patients with in-hospital detection of VRE later than 48 h after admission were included and comprised 116 VRE-positive cases and 116 VRE-negative matched controls. VRE isolates of cases were typed by multi-locus sequence typing.

RESULTS

ST117 was identified as the dominant VRE sequence type. Next to length of stay in hospital or on an intensive care unit and previous dialysis the case-control study revealed previous antibiotic therapy as a risk factor for the in-hospital detection of VRE. The antibiotics piperacillin/tazobactam, meropenem, and vancomycin were associated with the highest risks. After taking into account length of stay in hospital as possible confounder other potential contact-related risk factors such as previous sonography, radiology, central venous catheter, and endoscopy were not significant.

CONCLUSIONS

Previous dialysis and previous antibiotic therapy were identified as independent risk factors for the presence of VRE in surgical inpatients.

Treatment of Enterococcus faecalis Infective Endocarditis: A Continuing Challenge

Today, Enterococcus faecalis is one of the main causes of infective endocarditis in the world, generally affecting an elderly and fragile population, with a high mortality rate. Enterococci are partially resistant to many commonly used antimicrobial agents such as penicillin and ampicillin, as well as high-level resistance to most cephalosporins and sometimes carbapenems, because of low-affinity penicillin-binding proteins, that lead to an unacceptable number of therapeutic failures with monotherapy. For many years, the synergistic combination of penicillins and aminoglycosides has been the cornerstone of treatment, but the emergence of strains with high resistance to aminoglycosides led to the search for new alternatives, like dual beta-lactam therapy. The development of multi-drug resistant strains of Enterococcus faecium is a matter of considerable concern due to its probable spread to E. faecalis and have necessitated the search of new guidelines with the combination of daptomycin, fosfomycin or tigecycline. Some of them have scarce clinical experience and others are still under investigation and will be analyzed in this review. In addition, the need for prolonged treatment (6–8 weeks) to avoid relapses has forced to the consideration of other viable options as outpatient parenteral strategies, long-acting administrations with the new lipoglycopeptides (dalbavancin or oritavancin), and sequential oral treatments, which will also be discussed.

Outcomes of Daptomycin Plus Ceftaroline Versus Alternative Therapy for Persistent Methicillin-resistant Staphylococcus aureus (MRSA) Bacteraemia

OBJECTIVES

This study aimed to evaluate both efficacy and safety of combination therapy with daptomycin plus ceftaroline (DAP/CPT) versus alternative therapy in the treatment of persistent methicillin-resistant Staphylococcus aureus bacteraemia (MRSAB).

METHODS

This retrospective, single-centre study investigated adult patients who underwent a change in antibiotic therapy for persistent MRSAB. Daptomycin plus ceftaroline was compared with alternative therapy after initial treatment with vancomycin or DAP monotherapy was modified. The primary outcome was in-hospital mortality, and several secondary efficacy and safety outcomes were evaluated.

RESULTS

A total of 68 patients with persistent MRSAB had initial therapy switched to DAP/CPT (n = 43) or alternative therapy (n = 25). In-hospital mortality was similar with DAP/CPT versus alternative therapy (16.3% vs. 16%; P = 1.0). On average, the total duration of bacteraemia was numerically 1 day less in patients switched to DAP/CPT (11.4 days vs. 12.5 days; P = 0.5). Daptomycin plus ceftaroline was de-escalated in 81% of patients after receiving combination therapy for an average of 12.5 days. Secondary outcomes, including rates of adverse events and emergence of antimicrobial resistance, were similar between the two groups.

CONCLUSIONS

Switching to DAP/CPT after approximately 1 week of persistent MRSA bacteraemia may result in similar clinical outcomes when compared with alternative therapy. Rates of adverse events and emergence of antimicrobial resistance were low without a statistically significant difference observed between DAP/CPT and alternative therapy. These findings, as well as the impact of earlier switch or prolonged treatment with the combination, require further investigation.

Impact of colonization with multidrug-resistant organisms on antibiotic prophylaxis in patients with cirrhosis and variceal bleeding

Background

The efficacy of antibiotic prophylaxis to prevent rebleeding or infection after variceal bleeding in patients with liver cirrhosis colonized with multidrug-resistant organisms (MDROs) is unknown.

Methods

In this retrospective study, patients with liver cirrhosis and endoscopically confirmed variceal bleeding who were treated at a tertiary care center in Germany and were screened for MDROs at the time of bleeding were eligible for inclusion. Efficacy of antibiotic prophylaxis was evaluated in patients stratified according to microbiological susceptibility testing.

Results

From 97 patients, the majority had decompensated liver cirrhosis (median MELD Score 17) and ACLF was present in half of the patients (47.4%). One third of patients were colonized with MDRO at baseline. De-novo infection until day 10 or the combination of de-novo infection or rebleeding were comparable among both groups (p = 0.696 and p = 0.928, log-rank-test). Risk of de-novo infection or rebleeding was not significantly increased in patients who received antibiotic prophylaxis that did not cover the MDRO found upon baseline screening. Acute-on-chronic liver failure at baseline was the strongest and only independent risk factor that was associated with both outcomes (OR 5.52, 95%-CI 1.48–20.61, p = 0.011 and OR 11.5, 95%-CI 2.70–48.62, p<0.001). Neither MDRO colonization at baseline nor covering all detected MDRO with antibiotic prophylaxis (i.e. “adequate” prophylaxis) impacted transplant-free survival. Again, the presence of ACLF was the strongest independent risk factor associated with mortality (OR 9.85, 95%-CI 3.58–27.12, p<0.0001).

Conclusion

In this study, MDRO colonization did not increase the risk of rebleeding, infections nor death, even if antibiotic prophylaxis administered did not cover all MDRO detected at MDRO screening. Patients with ACLF had an increased risk of bleeding, infections and death.

Optimizing antibiotic therapies to reduce the risk of bacterial resistance

The incidence of infections caused by bacteria that are resistant to antibiotics is constantly increasing. In Europe alone, it has been estimated that each year about 33'000 deaths are attributable to such infections. One important driver of antimicrobial resistance is the use and abuse of antibiotics in human medicine. Inappropriate prescribing of antibiotics is still very frequent: up to 50% of all antimicrobials prescribed in humans might be unnecessary and several studies show that at least 50% of antibiotic treatments are inadequate, depending on the setting. Possible strategies to optimize antibiotic use in everyday clinical practice and to reduce the risk of inducing bacterial resistance include: the implementation of rapid microbiological diagnostics for identification and antimicrobial susceptibility testing, the use of inflammation markers to guide initiation and duration of therapies, the reduction of standard durations of antibiotic courses, the individualization of antibiotic therapies and dosing considering pharmacokinetics/pharmacodynamics targets, and avoiding antibiotic classes carrying a higher risk for induction of bacterial resistance. Importantly, measures to improve antibiotic prescribing and antibiotic stewardship programs should focus on facilitating clinical reasoning and improving prescribing environment in order to remove any barriers to good prescribing.

Multidrug-resistant infections in solid organ transplant recipients: a focus on risk factors, prevention and treatment strategies

Solid organ transplantation is the best therapeutic option for patients with end-stage organ disease and, according to the data from international registries, there has been a steady increase in numbers and results. However, post-transplant infections remain a fearsome complication with, in the last decade, an increasing incidence of episodes due to antibiotic-resistant bacteria and opportunistic agents. In this paper, we summarize the most relevant and updated knowledge concerning infections from multidrug-resistant germs in solid organ transplant recipients, focusing on risk factors, treatment and prevention strategies, and antimicrobial pharmacokinetics relevant to this particular population of patients.

Do Inpatient Antimicrobial Stewardship Programs Help Us in the Battle Against Antimicrobial Resistance?

BACKGROUND

Antibiotic stewardship programs (ASPs) have demonstrated success at reducing costs, yet there is limited quality evidence of their effectiveness in reducing infections of high-profile drug-resistant organisms.

METHODS

This retrospective, cohort study included all Kaiser Permanente Southern California (KPSC) members aged ≥18 years hospitalized in 9 KPSC hospitals from 1 January 2008 to 31 December 2016. We measured the impact of staggered ASP implementation on consumption of 18 ASP-targeted antibiotics using generalized linear mixed-effects models. We used multivariable generalized linear mixed-effects models to estimate the adjusted effect of an ASP on rates of infection with drug-resistant organisms. Analyses were adjusted for confounding by time, cluster effects, and patient- and hospital-level characteristics.

RESULTS

We included 765 111 hospitalizations (288 257 pre-ASP, 476 854 post-ASP). By defined daily dose, we found a 6.1% (-7.5% to -4.7%) overall decrease antibiotic use post-ASP; by days of therapy, we detected a 4.3% (-5.4% to -3.1%) decrease in overall use of antibiotics. The number of prescriptions increased post-ASP (1.04 [1.03-1.05]). In adjusted analyses, we detected an overall increase in vancomycin-resistant enterococci infections post-ASP (1.37 [1.10-1.69]). We did not detect a change in the rates of extended-spectrum beta-lactamase, carbapenem-resistant Enterobacteriaceae, and multidrug-resistant Pseudomonas aeruginosa infections post-ASP.

CONCLUSIONS

ASPs with successful reductions in consumption of targeted antibiotics may not see changes in infection rates with antibiotic-resistant organisms in the 2 to 6 years post-implementation. There are likely differing timescales for reversion to susceptibility across organisms and antibiotics, and unintended consequences from compensatory prescribing may occur.

Ceftriaxone versus antistaphylococcal antibiotics for definitive treatment of methicillin-susceptible Staphylococcus aureus infections: a systematic review and meta-analysis

Optimal therapy for methicillin-susceptible Staphylococcus aureus (MSSA) infections is unclear. Current standard of care consists of antistaphylococcal antibiotics (ASAs) such as nafcillin, oxacillin and cefazolin. Ceftriaxone has been evaluated due to its advantage as a once-daily outpatient regimen. However, questions remain regarding its efficacy compared with ASAs. We aimed to conduct a review and synthesis of available literature for outcomes of patients treated with ceftriaxone or ASAs for MSSA infections. We searched Cochrane Central Register of Controlled Trials, Embase Ovid, MEDLINE Ovid, Scopus and Web of Science (1990 to June 2021). Risk of bias for cohort studies was assessed by the Newcastle-Ottawa scale. We pooled risk ratios (RRs) using the DerSimonian-Laird random-effects model for outcomes of those receiving ceftriaxone versus ASAs. Heterogeneity was assessed by the I² index. From 459 identified studies, 7 were included in the quantitative synthesis totalling 1640 patients. Definitive therapy with ceftriaxone was associated with a lower risk of toxicity requiring therapy alteration (RR 0.49, 95% CI 0.27-0.88; I² = 0%). There was no difference in terms of 90-day all-cause mortality (RR 0.93, 95% CI 0.46-1.88; I² = 9%), hospital readmission (RR 0.96, 95% CI 0.57-1.64; I² = 0%) or infection recurrence (RR 1.04, 95% CI 0.63-1.72; I² =0%). Current evidence suggests there is no difference in efficacy between ceftriaxone and ASAs for MSSA infection, with a lower risk of toxicity with ceftriaxone. Within the limitations of available retrospective studies, ceftriaxone is a consideration for definitive therapy of MSSA infection. [Trial registration: PROSPERO ID: CRD42021259086].

Time to abandon ampicillin plus gentamicin in favour of ampicillin plus ceftriaxone in Enterococcus faecalis infective endocarditis? A meta-analysis of comparative trials

Background

Current guidelines recommend either ampicillin plus ceftriaxone (AC) or amoxicillin/ampicillin plus gentamicin (AG) with an equivalent class IB recommendation in Enterococcus faecalis endocarditis. However, previous observational studies suggest that AC might be favourable in terms of adverse events.

Objectives

To investigate whether AC is non-inferior to AG, and if it is associated with less adverse events.

Methods

In June 2021, a systematic literature search using the databases PubMed/MEDLINE, CDSR, CENTRAL, CCAs, EBM Reviews, Web of Science and LILACS was conducted by two independent reviewers. Studies were considered eligible if (P) patients included were ≥ 18 years of age and had IE with E. faecalis, (I) treatment with AC was compared to (C) treatment with AG and (O) outcomes on in-hospital mortality, nephrotoxicity and adverse events requiring drug withdrawal were reported. Odds ratios and 95% confidence intervals were calculated using random-effects models with the Mantel–Haenszel method, the Sidik–Jonkman estimator for τ² and the Hartung–Knapp adjustment.

Results

Treatment with AC was non-inferior to AG, as depicted by no significant differences in-hospital mortality, 3-month mortality, relapses or treatment failure. Furthermore, AC was associated with a lower prevalence of nephrotoxicity (OR 0.45 [0.26–0.77], p = 0.0182) and drug withdrawal due to adverse events (OR 0.11 [0.03–0.46], p = 0.0160) than AG.

Conclusions

Treatment with AC was non-inferior to treatment with AG, and it was associated with a reduced prevalence of nephrotoxicity and drug withdrawal due to adverse events. Thus, combination therapy with AC appears favourable over AG in patients with E. faecalis IE.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01971-3.

Factors associated with vanA VRE acquisition in Cardiothoracic Surgery patients during an acute outbreak

BACKGROUND

There was an acute outbreak of vanA Enterococcus faecium (VREfm) in a tertiary Melbourne teaching hospital between 2015 and 2016 amongst Cardiothoracic Surgery (CTS) ward and Intensive Care Unit (ICU) patients. Prior to this outbreak vanB VRE had been the predominate genotype encountered.

METHODS

A retrospective, matched (1:2), case-control study was conducted on CTS patients between 1 August 2015 and 31 May 2016 admitted to a hospital in Melbourne, during an outbreak of vanA VREfm to identify factors associated with colonisation or infection. Factors assessed included undergoing surgery and type of procedure, exposure to antibiotics and admission to ICU.

RESULTS

During the outbreak, 56 new cases of vanA VREfm out of 802 CTS ward patients were identified. Of these new cases, 52 were included in the case-control analysis, all identified via rectal screening. Cases had significantly longer duration of stay in hospital (p < 0.001) than controls. Multivariable analysis identified exposure to ceftriaxone as an independent factor (OR 4.14, p = 0.018) associated with new vanA VREfm isolates. Other factors such as vancomycin exposure, specific CTS procedures or ICU admission were not identified as independent factors. Ceftriaxone was being used during the outbreak as surgical prophylaxis amongst CTS patients.

CONCLUSION

Ceftriaxone use was associated with an increased risk of CTS patients acquiring vanA VREfm during an acute outbreak. This highlights the overall importance of antibiotic stewardship to minimise hospital-associated multi-drug resistant infections.

Treatment with Ceftriaxone in Complicated Diverticulitis Increases the Incidence of Intra-Abdominal Enterococcus faecium Detection

Background: Complicated diverticulitis of the sigmoid colon typically is treated by resection after initial antibiotic treatment. Third-generation cephalosporins are the drugs of choice but are not effective against enterococci and can induce colonic colonization by Enterococcus faecium within hours. Infections caused by enterococci, especially E. faecium, are difficult to treat but should be considered in the strategic treatment planning of hospital-acquired peritonitis (e.g., anastomotic leakage), especially in immunocompromised patients. Methods: To determine whether the duration of pre-operative ceftriaxone treatment in complicated diverticulitis increases the incidence of intra-abdominal E. faecium detection, we analyzed all patients operated on for diverticulitis of the sigmoid colon in our department between 2008 and 2016. Results: Analyzing 516 resections performed for complicated diverticulitis, we found that E. faecium generally was detected intra-abdominally more often in the group that underwent longer pre-operative ceftriaxone treatment (≥ 4 days). During primary resection, E. faecium was detected in 2.7%, 11.1%, and 37.0% cases in the group undergoing immediate operation, 1-3 days of antibiotic treatment, and ≥4 days of antibiotic treatment, respectively. Enterococcus faecium was detected in 0, 25.0%, and 70.6% of surgical revisions and 28.6%, 14.3%, and 56.0%, respectively, of incisional surgical site infections with identified pathogens. A multivariable analysis discovered anastomotic leakage and antibiotic treatment lasting ≥4 days to be independent risk factors for intra-abdominal isolation of E. faecium. Conclusion: A ceftriaxone treatment ≥4 days led to a higher incidence of intra-abdominal E. faecium. Our data further suggested that empiric coverage of E. faecium in the treatment of hospital-acquired peritonitis could be beneficial after a long duration of ceftriaxone treatment.

Enterococcus faecium: from microbiological insights to practical recommendations for infection control and diagnostics

Early in its evolution, Enterococcus faecium acquired traits that allowed it to become a successful nosocomial pathogen. E. faecium inherent tenacity to build resistance to antibiotics and environmental stressors that allows the species to thrive in hospital environments. The continual wide use of antibiotics in medicine has been an important driver in the evolution of E. faecium becoming a highly proficient hospital pathogen.For successful prevention and reduction of nosocomial infections with vancomycin resistant E. faecium (VREfm), it is essential to focus on reducing VREfm carriage and spread. The aim of this review is to incorporate microbiological insights of E. faecium into practical infection control recommendations, to reduce the spread of hospital-acquired VREfm (carriage and infections). The spread of VREfm can be controlled by intensified cleaning procedures, antibiotic stewardship, rapid screening of VREfm carriage focused on high-risk populations, and identification of transmission routes through accurate detection and typing methods in outbreak situations. Further, for successful management of E. faecium, continual innovation in the fields of diagnostics, treatment, and eradication is necessary.

Four weeks versus six weeks of ampicillin plus ceftriaxone in Enterococcus faecalis native valve endocarditis: A prospective cohort study

Enterococcus faecalis infective endocarditis (EFIE) is a severe disease of increasing incidence. The objective was to analyze whether the outcome of patients with native valve EFIE (NVEFIE) treated with a short course of ampicillin plus ceftriaxone (4wAC) was similar to patients treated according to international guidelines (6wAC). Between January 2008 and June 2018, 1,978 consecutive patients with definite native valve IE were prospectively included in a national registry. Outcomes of patients with NVEFIE treated with 4wAC were compared to those of patients who received 6wAC. Three hundred and twenty-two patients (16.3%) had NVEFIE. One hundred and eighty-three (56.8%) received AC. Thirty-nine patients (21.3%) were treated with 4wAC for four weeks and 70 patients (38.3%) with 6wAC. There were no differences in age or comorbidity. Patients treated 6wAC presented a longer duration of symptoms before diagnosis (21 days, IQR 7-60 days vs. 7 days, IQR 1-22 days; p = 0.002). Six patients presented perivalvular abscess and all of these received 6wAC. Surgery was performed on 14 patients (35.9%) 4wAC and 34 patients (48.6%) 6wAC (p = 0.201). In-hospital mortality, one-year mortality and relapses among 4wAC and 6wAC patients were 10.3% vs. 11.4% (p = 0.851); 17.9% vs. 21.4% (p = 0.682) and 5.1% vs. 4.3% (p = 0.833), respectively. In conclusion, a four-week course of AC may be considered as an alternative regimen in NVEFIE, notably in patients with shorter duration of symptoms and those without perivalvular abscess. These results support the performance of a randomized clinical trial to evaluate the efficacy of this short regimen.

Impact of antimicrobial therapy on the gut microbiome

The gut microbiome is now considered an organ unto itself and plays an important role in health maintenance and recovery from critical illness. The commensal organisms responsible for the framework of the gut microbiome are valuable in protection against disease and various physiological tasks. Critical illness and the associated interventions have a detrimental impact on the microbiome. While antimicrobials are one of the fundamental and often life-saving modalities in septic patients, they can also pave the way for subsequent harm because of the resulting damage to the gut microbiome. Contributing to many of the non-specific signs and symptoms of sepsis, the balance between the overuse of antimicrobials and the clinical need in these situations is often difficult to delineate. Given the potency of antimicrobials utilized to treat septic patients, the effects on the gut microbiome are often rapid and long-lasting, in which case full recovery may never be observed. The overgrowth of opportunistic pathogens is of significant concern as they can lead to infections that become increasingly difficult to treat. Continued research to understand the disturbances within the gut microbiome of critically ill patients and their outcomes is essential to help develop future therapies to circumvent damage to, or restore, the microbiome. In this review, we discuss the impact of the antimicrobials often used for the treatment of sepsis on the gut microbiota.

Epidemiology, treatment and outcomes of bloodstream infection due to vancomycin-resistant enterococci in cancer patients in a vanB endemic setting

Background

Vancomycin-resistant enterococcus (VRE) is an important cause of infection in immunocompromised populations. Few studies have described the characteristics of vanB VRE infection. We sought to describe the epidemiology, treatment and outcomes of VRE bloodstream infections (BSI) in a vanB predominant setting in malignant hematology and oncology patients.

Methods

A retrospective review was performed at two large Australian centres and spanning a 6-year period (2008–2014). Evaluable outcomes were intensive care admission (ICU) within 48 h of BSI, all-cause mortality (7 and 30 days) and length of admission.

Results

Overall, 106 BSI episodes were observed in 96 patients, predominantly Enterococcus faecium vanB (105/106, 99%). Antibiotics were administered for a median of 17 days prior to BSI, and 76/96 (79%) were neutropenic at BSI onset. Of patients screened before BSI onset, 49/72 (68%) were found to be colonised. Treatment included teicoplanin (59), linezolid (6), daptomycin (2) and sequential/multiple agents (21). Mortality at 30-days was 31%. On multivariable analysis, teicoplanin was not associated with mortality at 30 days.

Conclusions

VRE BSI in a vanB endemic setting occurred in the context of substantive prior antibiotic use and was associated with high 30-day mortality. Targeted screening identified 68% to be colonised prior to BSI. Teicoplanin therapy was not associated with poorer outcomes and warrants further study for vanB VRE BSI in cancer populations.

Companion psittacine birds as reservoir of gentamicin and vancomycin-resistant Enterococcus spp

ABSTRACT: Enterococcus are recognized worldwide as significant nosocomial agents that have been continuously envolving to adapt to different niches and acquire resistance to several antibiotic classes. Vancomycin and gentamicin-resistant strains of E. faecalis and E. faecium have been associated with nosocomial human infections. Some epidemiological studies suggest the participation of pets as reservoirs of vancomycin and gentamicin-resistant Enterococcus strains. However, the role of companion birds as reservoirs of these strains has been poorly studied. In this study, 126 psittacine birds were evaluated and 26.9% carried Enterococcus spp., including the species E. faecalis, E. faecium, E. hirae, E. phoeniculicola, E. gallinarum and E. casseliflavus. The antibiotic resistance profile showed four high-level gentamicin-resistance (HLGR) strains. In addition, two strains presented intermediate levels of vancomycin resistance. Resistant strains were isolated from fecal and oropharynx samples of sick and clinically healthy birds, suggesting that psittacine birds may act as reservoirs of HLGR Enterococcus spp. However, sick birds appear to be more implicated in the enterococci transmission than healthy birds.

CRISPR-Cas9-mediated genome editing in vancomycin-resistant Enterococcus faecium

The Gram-positive bacterium Enterococcus faecium is becoming increasingly prevalent as a cause of hospital-acquired, antibiotic-resistant infections. A fundamental part of research into E. faecium biology relies on the ability to generate targeted mutants but this process is currently labour-intensive and time-consuming, taking 4 to 5 weeks per mutant. In this report, we describe a method relying on the high recombination rates of E. faecium and the application of the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-Cas9 genome editing tool to more efficiently generate targeted mutants in the E. faecium chromosome. Using this tool and the multi-drug resistant clinical E. faecium strain E745, we generated a deletion mutant in the lacL gene, which encodes the large subunit of the E. faeciumβ-galactosidase. Blue/white screening using 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) could be used to distinguish between the wild-type and lacL deletion mutant. We also inserted two copies of gfp into the intrinsic E. faecium macrolide resistance gene msrC to generate stable green fluorescent cells. We conclude that CRISPR-Cas9 can be used to generate targeted genome modifications in E. faecium in 3 weeks, with limited hands-on time. This method can potentially be implemented in other Gram-positive bacteria with high intrinsic recombination rates.

A Review of Combination Antimicrobial Therapy for Enterococcus faecalis Bloodstream Infections and Infective Endocarditis

Enterococci, one of the most common causes of hospital-associated infections, are responsible for substantial morbidity and mortality. Enterococcus faecalis, the more common and virulent species, causes serious high-inoculum infections, namely infective endocarditis, that are associated with cardiac surgery and mortality rates that remained unchanged for the last 30 years. The best cures for these infections are observed with combination antibiotic therapy; however, optimal treatment has not been fully elucidated. It is the purpose of this review to highlight treatment options and their limitations, and provide direction for future investigative efforts to aid in the treatment of these severe infections. While ampicillin plus ceftriaxone has emerged as a preferred treatment option, mortality rates continue to be high, and from a safety standpoint, ceftriaxone, unlike other cephalosporins, promotes colonization with vancomycin resistant-enterococci due to high biliary concentrations. More research is needed to improve patient outcomes from this high-mortality disease.

Antimicrobial Treatment of Infective Endocarditis, Caused by Enterococcus Faecalis. RATIONAL PHARMACOTHERAPY IN CARDIOLOGY 2019. [DOI: 10.20996/1819-6446-2019-15-4-586-592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The frequency of infective endocarditis (IE) has increased 3 times over the past 30 years. The incidence of IE morbidity is recorded in all countries of the world and in the Russian Federation more than 40 people per 1 million population get sick. One of the most frequent causative agents of infective endocarditis is Enterococcus faecalis (E. faecalis), which takes the third place in the structure of the frequency of IE pathogens. Enterococcal IE remains a disease with high mortality, despite the emergence of new groups of antibacterial drugs. This review includes the results of studies of the efficacy and safety of various antimicrobial regimens of IE caused by E. faecalis. The analysis of data from foreign and native studies of antimicrobial treatment in patients with infective endocarditis, accompanied by enterococcal bacteremia is presented in the review. The search for literature performed by using medical databases: MEDLINE, EMBASE, eLIBRARY. The current review included studies of the efficacy and safety of antimicrobial treatment. The main antibiotic therapy regimens of IE caused by E. faecalis include 2 beta-lactam antibiotics or a combination of ampicillin and gentamicin, according to the results of 5 found studies. Found antimicrobial regimens significantly did not affect mortality. Data from international registries testify to the efficacy and safety of daptomycin monotherapy for enterococcal endocarditis. Linezolid and daptomycin are the main drugs of treating infective endocarditis caused by vancomycin-resistant enterococci. Native studies report of a high level of resistance of enterococcal strains to beta-lactam antibacterial drugs. The duration of fever, the frequency of surgical heart valves interventions, the duration of bacteremia are not fully represented in each of the studies, and it is difficult to evaluate these factors. Ampicillin+ceftriaxone and ampicillin+gentamicin are the main antimicrobial treatment regimens of enterococcal endocarditis. Efficacy of these regimens is not significantly different. Treatment of IE should be carried out taking into the epidemiological situation and the strain resistance.

Vancomycin-resistant Enterococcus in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation address vancomycin-resistant enterococci (VRE) infections in SOT candidates and recipients. VRE are an important cause of infection and have been named by the CDC as a serious public threat. Typically, a commensal of the gastrointestinal tract, VRE may become pathogenic after abdominal organ manipulation like transplantation. This guideline reviews the microbiology, antimicrobial resistance mechanisms, epidemiology, and clinical manifestations of VRE infection in the context of solid organ transplantation. Treatment regimens including combination therapies and novel investigational agents are also reviewed. Finally, an updated appraisal of infection control measures relevant to VRE infection and colonization is presented.

Efficacy and safety of intravenous ceftriaxone at home versus intravenous flucloxacillin in hospital for children with cellulitis (CHOICE): a single-centre, open-label, randomised, controlled, non-inferiority trial

BACKGROUND

Outpatient parenteral antimicrobial therapy in children is common despite no evidence of its efficacy or safety from clinical trials. We aimed to compare the efficacy and safety of intravenous antibiotic therapy at home with that of standard treatment in hospital for children with moderate to severe cellulitis.

METHODS

The Cellulitis at Home or Inpatient in Children from the Emergency Department (CHOICE) trial was a randomised, controlled, non-inferiority trial in children aged 6 months to 18 years who presented to the emergency department at The Royal Children's Hospital (Melbourne, VIC, Australia) with uncomplicated moderate to severe cellulitis. Participants were randomly assigned to receive either intravenous ceftriaxone (50 mg/kg once daily) at home or intravenous flucloxacillin (50 mg/kg every 6 h) in hospital with web-based randomisation, stratified by age and periorbital cellulitis. The primary outcome was treatment failure, which was defined as no clinical improvement or occurrence of an adverse event, resulting in a change in empiric antibiotics within 48 h of the first dose. Secondary outcomes included adverse events and acquisition of antibiotic-resistant bacteria. Outcomes were assessed in all randomised participants with outcome data (intention-to-treat population) and in all individuals who received treatment as allocated and did not have any major protocol violations (per-protocol population). For home treatment to be non-inferior to hospital treatment, the difference between groups in the proportion of children with treatment failure in the intention-to-treat population had to be less than 15%. This trial is registered with ClinicalTrials.gov, number NCT02334124.

FINDINGS

Between Jan 9, 2015, and June 15, 2017, we screened 1135 children for eligibility, of whom 190 were randomly assigned to receive ceftriaxone at home (n=95) or flucloxacillin in hospital (n=95). The intention-to-treat analysis comprised 188 children (93 in the home group and 95 in the hospital group) because two children in the home group were found to be ineligible after randomisation and were excluded. Treatment failure occurred in two (2%) children in the home group and in seven (7%) children in the hospital group (risk difference -5·2%, 95% CI -11·3 to 0·8, p=0·088). In the per-protocol analysis, treatment failure occurred in one (1%) of 89 children in the home group and in seven (8%) of 91 children in the hospital group (-6·5%, -12·4 to -0·7). Fewer children treated at home than in hospital had an adverse event (two [2%] vs ten [11%]; p=0·048). There was no difference between groups in rates of nasal acquisition of meticillin-resistant Staphylococcus aureus or gastrointestinal acquisition of extended-spectrum β-lactamase-producing bacteria or Clostridium difficile after 3 months.

INTERPRETATION

Home treatment with intravenous ceftriaxone is not inferior to treatment in hospital with intravenous flucloxacillin for children with cellulitis. The standard of care for the intravenous treatment of uncomplicated cellulitis in children should be home or outpatient care when feasible.

FUNDING

The Royal Children's Hospital Foundation and Murdoch Children's Research Institute.

An outbreak of vanA vancomycin-resistant Enterococcus faecium in a hospital with endemic vanB VRE

BACKGROUND

In Australia, vanB vancomycin-resistant Enterococcus faecium (VREfm) has been endemic for over 20 years, but vanA VREfm isolates have rarely been reported.

METHODS

This outbreak report describes an outbreak of vanA VREfm in the intensive care unit (ICU) and cardiothoracic surgery (CTS) wards of a Melbourne hospital in 2015-2016. After the cluster was initially identified in the ICU ward, an active screening programme was implemented. VRE isolates were typed using in silico multi-locus sequence typing. In addition, to screening, enhanced environmental cleaning, chlorhexidine gluconate body washes, and standardisation of the surgical antibiotic prophylaxis regimen were implemented to control the outbreak.

RESULTS

There were 83 new isolates of vanA VREfm recovered from patients in the ICU (n = 31) and CTS (n = 52) wards. Screening identified 78 (94%) of cases. Three patients required treatment for clinical infection with vanA VREfm during the outbreak. The outbreak was polyclonal with 5 different multilocus sequence types carrying the vanA gene (ST17, ST80, ST203, ST252 and ST1421) detected from a subset of isolates (N = 43). The ST17 isolates all carried both the vanA and vanB gene. The intervention bundle resulted in control of the outbreak after 10 months.

CONCLUSION

Geographically, vanA VREfm has previously been uncommon in the region and this outbreak represents a change in local epidemiology. Few VRE outbreaks have been reported in CTS patients. The infection control responses controlled the outbreak within 10-months and may help guide future management of outbreaks.

Surveillance of Antibiotic Use and Resistance in Intensive Care Units (SARI)

BACKGROUND

The project entitled Surveillance of Antibiotic Use and Resistance in Intensive Care Units (SARI) was initiated in Germany in 2000. In this article, we describe developments in antibiotic use and resistance rates in the participating intensive care units over the years 2001-2015.

METHODS

The intensive care units supplied monthly figures on patient days, antibiotic use (in defined daily doses, DDD), and resistance data for 13 pathogens. The density of antibiotic use per 1000 patient days was calculated on the basis of antibiotic use, DDD, and patient days, and the resistance density per 1000 patient days was calculated from the number of resistant pathogens.

RESULTS

In the years 2001-2015, data on 2 920 068 patient days were collected in 77 intensive care units. The average overall antibiotic use rose by 19% over this period, with a marked increase in the density of carbapenem use (from 76 to 250 DDD per 1000 patient days, +230%) and piperacillin-tazobactam use (from 42 to 146 DDD per 1000 patient days, +247%). The proportion of Escherichia coli and Klebsiella pneumoniae isolates that were resistant to third-generation cephalosporins increased markedly initially, then remained stable over the remainder of the observation period. The proportion of methicillin-resistant Staphylococcus aureus was stable over the entire period. The rates of vancomycin resistance among Enterococcus faecium isolates and imipenem resistance among gram-negative pathogens increased from 2.3% to 13.3% and from 0.1% to 0.3%, respectively.

CONCLUSION

The resistance density of gram-negative multiresistant pathogens in the participating intensive care units increased markedly. The rise in imipenem-resistant pathogens arouses particular concern. The increased use of broad-spectrum/reserve antibiotics may well have contributed to this development. Efforts to use antibiotics rationally, e.g., with the support of multidisciplinary "antibiotic stewardship" teams, are therefore vitally important. As participation in SARI is voluntary, these surveillance data cannot be considered representative of Germany as a whole.

Evaluation of ceftriaxone prescriptions in the emergency department of a university hospital: an urgent need for improvement and alternative therapy

To evaluate the relevance of ceftriaxone prescriptions in an emergency department of a university hospital and suggest whenever possible an antibiotic alternative with a lower ecological impact. All ceftriaxone prescriptions in the first complete week of each month during the year 2016, in the emergency department of the Grenoble university hospital, have been analyzed by an IDS referent in antibiotic prescriptions. Ceftriaxone prescription was considered appropriate if justified (an antibiotic must be used), relevant (ceftriaxone is a good choice), and adapted (in terms of dose, route, and period of administration), regardless of a potential antibiotic association, consistent with international recommendations. We considered patient outcome regarding the quality of initial prescription. Additionally, alternatives were suggested for relevant prescriptions. We included 327 patients, of which ceftriaxone prescriptions were not appropriate in 37.6% of cases: 13.5% were not justified, 12.8% not relevant, and 11.3% not adapted. The main factors associated with unjustified prescriptions were urinary, dermatological, and less frequent infection sites (p < 0.001). The main factors associated with irrelevant prescriptions were patients carrying multi-resistant bacteria (p = 0.002) or already following an antibiotic prescription at emergency department admission (p = 0.024). Antibiotic prescriptions were poorly adapted in patients with a creatinine rate over 150 μmol/L (p < 0.001) and septic shocks (p = 0.032). No difference was found concerning the hospital length of stay comparing appropriate initial prescriptions to inappropriate ones. However, alternatives with lower ecological impact were suggested in 55.2% of relevant prescriptions. In emergency departments, it is crucial to preserve ceftriaxone, selecting better indications and considering alternatives.

Vancomycin-resistant enterococcus infection in the hematopoietic stem cell transplant recipient: an overview of epidemiology, management, and prevention

Vancomycin-resistant enterococcus (VRE) is now one of the leading causes of nosocomial infections in the United States. Hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of VRE colonization and infection. VRE has emerged as a major cause of bacteremia in this population, raising important clinical questions regarding the role and impact of VRE colonization and infection in HSCT outcomes as well as the optimal means of prevention and treatment. We review here the published literature and scientific advances addressing these thorny issues and provide a rational framework for their approach.

The effect of antibiotic use on prevalence of nosocomial vancomycin-resistant enterococci- an ecologic study

Background

Vancomycin-resistant enterococci (VRE) are among the most common antimicrobial-resistant pathogens causing nosocomial infections. Although antibiotic use has been identified as a risk factor for VRE, it remains unclear which antimicrobial agents particularly facilitate VRE selection. Here, we assessed whether use of specific antimicrobial agents is independently associated with healthcare-associated (HA) VRE rates in a university hospital setting in Berlin, Germany.

Methods

We conducted the study between January 2014 and December 2015 at the Charité-university hospital of Berlin, Germany. From the hospital pharmacy, we extracted data for all antibacterials for systemic use (anatomical therapeutic chemical (ATC)-classification J01) and calculated ward specific antibiotic consumption in defined daily doses (DDDs) per 100 patient-days (PD). We used the microbiology laboratory database to identify all patients with isolation of invasive or non-invasive VRE and calculated HA-VRE incidence as nosocomial VRE-cases per 100 patients and HA-VRE incidence density as nosocomial VRE-cases per 1000 PD. We defined VRE isolates as hospital-acquired if they were identified three days or later after hospital admission and otherwise as community-acquired (CA-VRE). We performed univariable and multivariable regression analyses to estimate the association of the frequency of HA-VRE per month with antibiotic use and other parameters such as length of stay, type of ward or presence of at least one CA-VRE on ward. In a second analysis, we considered only patients with VRE infections.

Results

We included data from 204,054 patients with 948,380 PD from 61 wards. Overall, 1430 VRE-cases were identified of which 409 (28.6%) were considered hospital-acquired (HA). We found that carbapenem use in the current month and prior-month use of glycopeptides increased the risk for HA-VRE by 1% per 1 DDD/100 PD and 3% per 1 DDD/100 PD, respectively. However, when only VRE from clinical samples were considered, only glycopeptide use showed a statistically significant association. In both models, detection of at least one patient with CA-VRE on a ward in the current month significantly increased the risk of HA-VRE, thereby indicating nosocomial spread of VRE.

Conclusions

Our findings suggest that the risk of HA-VRE is associated with specific antimicrobial agents. Prudent use of these antimicrobial agents might reduce nosocomial VRE rates. That appearance of at least one CA-VRE case on the ward increased the risk of HA-VRE detection highlights the importance of strict hand hygiene practices to interrupt person-to-person transmission of VRE.

Multidrug-Resistant Bacteria in the Community: Trends and Lessons Learned

Multidrug resistant (MDR) bacteria are one of the most important threats to public health. Typically, MDR bacteria are associated with nosocomial infections. However, some MDR bacteria have become prevalent causes of community-acquired infections. The spread of MDR bacteria into the community is a crucial development, and is associated with increased morbidity, mortality, health care costs, and antibiotic use. Factors associated with community dissemination of MDR bacteria overlap but are distinct from those associated with nosocomial spread. Prevention of further community spread of MDR bacteria is of the utmost importance, and requires a multidisciplinary approach involving all stakeholders.

Patient-level analysis of incident vancomycin-resistant enterococci colonization and antibiotic days of therapy

Vancomycin-resistant enterococci (VRE) infections are a public health threat associated with increased patient mortality and healthcare costs. Antibiotic usage, particularly cephalosporins, has been associated with VRE colonization and VRE bloodstream infections (VRE BSI). We examined the relationship between antimicrobial usage and incident VRE colonization at the individual patient level. Prospective, weekly surveillance was undertaken for incident VRE colonization defined by negative admission but positive surveillance swab in a medical intensive care unit over a 17-month period. Antimicrobial exposure was quantified as days of therapy (DOT)/1000 patient-days. Multiple logistic regression was used to analyse incident VRE colonization and antibiotic DOT, controlling for demographic and clinical covariates. Ninety-six percent (1398/1454) of admissions were swabbed within 24 h of intensive care unit (ICU) arrival and of the 380 patients in the ICU long enough for weekly surveillance, 83 (22%) developed incident VRE colonization. Incident colonization was associated in bivariate analysis with male gender, more previous hospital admissions, longer previous hospital stay, and use of cefepime/ceftazidime, fluconazole, azithromycin, and metronidazole (P < 0·05). After controlling for demographic and clinical covariates, metronidazole was the only antibiotic independently associated with incident VRE colonization (odds ratio 2·0, 95% confidence interval 1·2-3·3, P < 0·009). Our findings suggest that risk of incident VRE colonization differs between individual antibiotic agents and support the possibility that antimicrobial stewardship may impact VRE colonization and infection.

Structure and Dimerization of IreB, a Negative Regulator of Cephalosporin Resistance in Enterococcus faecalis

Enterococcus faecalis, a leading cause of hospital-acquired infections, exhibits intrinsic resistance to most cephalosporins, which are antibiotics in the beta-lactam family that target cell-wall biosynthesis. A comprehensive understanding of the underlying genetic and biochemical mechanisms of cephalosporin resistance in E. faecalis is lacking. We previously determined that a transmembrane serine/threonine kinase (IreK) and its cognate phosphatase (IreP) reciprocally regulate cephalosporin resistance in E. faecalis, dependent on the kinase activity of IreK. Other than IreK itself, thus far the only known substrate for reversible phosphorylation by IreK and IreP is IreB, a small protein of unknown function that is well conserved in low-GC Gram-positive bacteria. We previously showed that IreB acts as a negative regulator of cephalosporin resistance in E. faecalis. However, the biochemical mechanism by which IreB modulates cephalosporin resistance remains unknown. As a next step toward an understanding of the mechanism by which IreB regulates resistance, we initiated a structure-function study on IreB. The NMR solution structure of IreB was determined, revealing that IreB adopts a unique fold and forms a dimer in vitro. Dimerization of IreB was confirmed in vivo. Substitutions at the dimer interface impaired IreB function and stability in vivo, indicating that dimerization is functionally important for the biological activity of IreB. Hence, these studies provide new insights into the structure and function of a widely conserved protein of unknown function that is an important regulator of antimicrobial resistance in E. faecalis.

Risk Factors and Outcomes of Vancomycin-Resistant Enterococcus Colonization in Patients on Peritoneal Dialysis: A Single-Center Study in Hong Kong

BACKGROUND

Vancomycin-resistant Enterococcus (VRE) colonization is common among patients with chronic kidney disease. However, data concerning VRE colonization among patients receiving peritoneal dialysis (PD) is lacking. The aim of this study is to evaluate the risk factors and various clinical outcomes for VRE colonization among PD patients.

METHODS

This is a retrospective cohort study of 166 PD patients who were hospitalized between 1 August 2013 and 31 July 2014. They were screened for VRE colonization status during a major VRE outbreak in Hong Kong in 2013 and were then categorized into 2 groups: VRE-positive and VRE-negative. The primary outcome was all-cause mortality while the secondary outcomes included VRE infection, PD-related peritonitis, and length of hospitalization.

RESULTS

Twenty-eight patients (16.9%) belonged to the VRE-positive group. Multivariate analysis showed that previous contact with VRE-positive patients (odds ratio [OR]: 417.86; 95% confidence interval [CI]: 17.21 - 10,147.26, p < 0.01), vancomycin use in previous 3 months (OR: 130.32; 95% CI: 5.35 - 3,176.30, p < 0.01), and old age (OR: 1.13; 95% CI: 1.02 - 1.24, p = 0.02) were the independent risk factors for VRE colonization. Patients in the VRE-positive group had significantly longer length of hospitalization, but there was no significant difference in all-cause mortality and peritonitis-free survival.

CONCLUSION

Vancomycin-resistant Enterococcus colonization is important among hospitalized PD patients. Cautious use of antibiotics and infection control measures are necessary to prevent VRE spreading, especially in high-risk patients.

Emerging trends in antibiotic resistance: Implications for emergency medicine

BACKGROUND

Many bacteria are demonstrating increasing levels of resistance to commonly used antibiotics. While this has implications for the healthcare system as a whole, many patients infected with these resistant organisms will initially present to the emergency department (ED). The purpose of this review is to provide a summary of current trends in infections caused by the most clinically relevant resistant organisms encountered in emergency medicine.

METHODS

Bacteria were selected based on the Centers for Disease Control and Prevention's National Action Plan for Combating Antibiotic Resistant Bacteria, and PubMed database.

RESULTS

The following bacteria were included: methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococci, Escherichia coli, carbapenem-resistant Enterobacteriaceae, Neisseria gonorrhoeae, and Pseudomonas aeruginosa. All have shown increasing rates of resistance to one or more of the antibiotics commonly used to treat them. Increasing rates of antibiotic resistance are associated with worse clinical outcomes and greater healthcare costs.

CONCLUSIONS

Antibiotic resistance is increasing and poses significant a risk to both the patient and public health as a whole. Appropriate choice of initial antibiotic is important in improving clinical outcomes, which is often the role of the ED provider. On a broader level, the ED must also take part in institutional efforts such as Antibiotic Stewardship Programs, which have been shown to decrease costs and rates of infection with resistant organisms. Ultimately, a multifaceted approach will be required to curb the threat of antibiotic-resistant bacteria.

[Antibiotic stewardship: Measures for optimization of antibacterial therapy]

Because the development of resistance is steadily increasing, especially among Gram-negative pathogens and new developments in antibiotics are lacking, a rational antibiotic therapy is necessary now more than ever. A continuing uncritical and non-guideline-conform use of antibiotics leads to selection of multidrug-resistant pathogens, which can colonize patients and as instigators of infections make treatment more difficult. A prerequisite for targeted antibiotic therapy is a critical testing of the suspected infection diagnosis based on a guideline-conform microbiological preanalytical procedure. To promote a guideline-conform antibiotic therapy in hospitals with respect to choice of substance, dosage and duration, in December 2013 so-called antibiotic stewardship (ABS) measures were summarized in a so-called S3-guideline from the Association of the Scientific Medical Societies in Germany (AWMF) under the auspices of the German Society for Infectious Diseases (DGI). With a strategy of targeted antibiotic therapy and infection prevention it is possible to achieve optimum treatment results and to minimize the development of resistance.

Ampicillin in Combination with Ceftaroline, Cefepime, or Ceftriaxone Demonstrates Equivalent Activities in a High-Inoculum Enterococcus faecalis Infection Model

Ampicillin-ceftriaxone combination therapy has become a predominant treatment for serious Enterococcus faecalis infections, such as endocarditis. Unfortunately, ceftriaxone use is associated with future vancomycin-resistant enterococcus colonization. We evaluated E. faecalis in an in vitro pharmacodynamic model against simulated human concentration-time profiles of ampicillin plus ceftaroline, cefepime, ceftriaxone, or gentamicin. Ampicillin-cefepime and ampicillin-ceftaroline demonstrated activities similar to those of ampicillin-ceftriaxone against E. faecalis.

Frequency, risk factors, and outcomes of vancomycin-resistant Enterococcus colonization and infection in patients with newly diagnosed acute leukemia: different patterns in patients with acute myelogenous and acute lymphoblastic leukemia

OBJECTIVE To determine the frequency, risk factors, and outcomes for vancomycin-resistant Enterococcus (VRE) colonization and infection in patients with newly diagnosed acute leukemia. DESIGN Retrospective clinical study with VRE molecular strain typing. SETTING A regional referral center for acute leukemia. PATIENTS Two hundred fourteen consecutive patients with newly diagnosed acute leukemia between 2006 and 2012. METHODS All patients had a culture of first stool and weekly surveillance for VRE. Clinical data were abstracted from the Intermountain Healthcare electronic data warehouse. VRE molecular typing was performed utilizing the semi-automated DiversiLab System. RESULTS The rate of VRE colonization was directly proportional to length of stay and was higher in patients with acute lymphoblastic leukemia. Risk factors associated with colonization include administration of corticosteroids (P=0.004) and carbapenems (P=0.009). Neither a colonized prior room occupant nor an increased unit colonization pressure affected colonization risk. Colonized patients with acute myelogenous leukemia had an increased risk of VRE bloodstream infection (BSI, P=0.002). Other risk factors for VRE BSI include severe neutropenia (P=0.04) and diarrhea (P=0.008). Fifty-eight percent of BSI isolates were identical or related by molecular typing. Eighty-nine percent of bloodstream isolates were identical or related to stool isolates identified by surveillance cultures. VRE BSI was associated with increased costs (P=0.0003) and possibly mortality. CONCLUSIONS VRE colonization has important consequences for patients with acute myelogenous leukemia undergoing induction therapy. For febrile neutropenic patients with acute myelogenous leukemia, use of empirical antibiotic regimens that avoid carbapenems and include VRE coverage may be helpful in decreasing the risks associated with VRE BSI.

A Qualitative Analysis of Implementation of Antimicrobial Stewardship at 3 Academic Hospitals: Understanding the Key Influences on Success

BACKGROUND

Inappropriate use of antimicrobials is linked to the development and spread of drug-resistant pathogens and is associated with increased morbidity, mortality, lengths of hospital stay, and health care costs. "Antimicrobial stewardship" is the umbrella term for an evidence-based knowledge translation strategy involving comprehensive quality improvement activities to optimize the use of antimicrobials, improve patient outcomes, reduce the development of antimicrobial resistance and hospital-acquired infections such as Clostridium difficile, and decrease health care costs.

OBJECTIVE

To assess the perceptions and experiences of antimicrobial stewardship program leaders in terms of clinicians' attitudes toward and behaviours related to antimicrobial prescribing.

METHODS

In this qualitative study, semistructured interviews were conducted with 6 antimicrobial stewards (2 physicians and 4 pharmacists) at 3 academic hospitals between June and August 2013.

RESULTS

The following 3 key themes emerged from the interviews: getting the right people on board, building collegial relationships, and rapidly establishing a track record. The study results elucidated the role and mechanisms that the program leader and other antimicrobial stewards used to influence other clinicians to engage in effective utilization of antimicrobials. The results also highlighted the methods employed by members of the antimicrobial stewardship team to tailor their strategies to the local context and to stakeholders of participating units; to gain credibility by demonstrating the impact of the antimicrobial stewardship program on clinical outcomes and cost; and to engage senior leaders to endorse and invest in the antimicrobial stewardship program, thereby adding to the antimicrobial stewards' credibility and their ability to influence the uptake of effective antimicrobial use.

CONCLUSIONS

Collectively, these results offer insight into processes and mechanisms of influence employed by antimicrobial stewards to enhance antimicrobial use among clinicians, which can in turn inform future implementation of antimicrobial stewardship and strategies for organizational change in hospitals.

The prevention and management of infections due to multidrug resistant organisms in haematology patients

Infections due to resistant and multidrug resistant (MDR) organisms in haematology patients and haematopoietic stem cell transplant recipients are an increasingly complex problem of global concern. We outline the burden of illness and epidemiology of resistant organisms such as gram-negative pathogens, vancomycin-resistant Enterococcus faecium (VRE), and Clostridium difficile in haematology cohorts. Intervention strategies aimed at reducing the impact of these organisms are reviewed: infection prevention programmes, screening and fluoroquinolone prophylaxis. The role of newer therapies (e.g. linezolid, daptomycin and tigecycline) for treatment of resistant and MDR organisms in haematology populations is evaluated, in addition to the mobilization of older agents (e.g. colistin, pristinamycin and fosfomycin) and the potential benefit of combination regimens.

Non-linear significant relationship between use of glycopeptides and isolation of vancomycin-resistant Enterococcus species in a university hospital setting

BACKGROUND

Emergence of colonization and infection with vancomycin-resistant enterococci (VRE) has become a worldwide challenge. To investigate whether the increasing incidence of VRE isolation can be correlated with use of glycopeptides in the hospital setting, we conducted a hospital-wide two-year study in the university hospital of Vienna.

METHODS

Within the period from January 2011 through December 2012 all patients with isolation of invasive or non-invasive VRE were retrospectively included. Specialty-specific data concerning the consumption of vancomycin and teicoplanin, fluoroquinolones and third generation cephalosporins in defined daily doses (DDDs) from June 2010 through May 2012 were extracted from the hospital pharmacy computer system. To assess the relationship between the usage of those antibiotics and the incidence of VRE (VRE-rate per 10 000 patients) a Poisson regression was performed.

FINDINGS

In the study period 266 patients were colonized or infected with VRE. Specialty-specific VRE isolation was as follows: general surgical units (44 patients), bone marrow transplant unit (35 patients), general medical units (33 patients), cardiothoracic surgery (27 patients), nephrology (26 patients), haematooncology (22 patients), gastroenterology (17 patients), urology (17 patients), and the infectious diseases unit (11 patients). Hospital-wide consumption of glycopeptides was higher for teicoplanin than for vancomycin (26 242 versus 8677 DDDs). Specialty-specific VRE incidence significantly increased with the use of glycopeptides, fluoroquinolones or third generation cephalosporins (p < 0.001). The results of the Poisson regression for vancomycin (p = 0.0018) and teicoplanin (p < 0.0001) separately were both highly significant. Spearman's correlation coefficient indicated a strong correlation between the two variables (rho = 0.8).

CONCLUSION

Overall usage of glycopeptides, fluoroquinolones or third generation cephalosporins contributed to the emergence of VRE in the hospital setting.

Residence in Skilled Nursing Facilities Is Associated with Tigecycline Nonsusceptibility in Carbapenem-Resistant Klebsiella pneumoniae

OBJECTIVE

To determine the rates of and risk factors for tigecycline nonsusceptibility among carbapenem-resistant Klebsiella pneumoniae (CRKPs) isolated from hospitalized patients.

DESIGN

Multicenter prospective observational study.

SETTING

Acute care hospitals participating in the Consortium on Resistance against Carbapenems in Klebsiella pneumoniae (CRaCKle).

PATIENTS

A cohort of 287 patients who had CRKPs isolated from clinical cultures during hospitalization.

METHODS

For the period from December 24, 2011 to October 1, 2013, the first hospitalization of each patient with a CRKP during which tigecycline susceptibility for the CRKP isolate was determined was included. Clinical data were entered into a centralized database, including data regarding pre-hospital origin. Breakpoints established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) were used to interpret tigecycline susceptibility testing.

RESULTS

Of 287 patients included in the final cohort, 155 (54%) had tigecycline-susceptible CRKPs. Of all index isolates, 81 (28%) were tigecycline-intermediate and 51 (18%) were tigecycline resistant. In multivariate modeling, independent risk factors for tigecycline nonsusceptibility were (1) admission from a skilled nursing facility (OR, 2.51; 95% CI, 1.51-4.21; P=.0004), (2) positive culture within 2 days of admission (OR, 1.82; 95% CI, 1.06-3.15; P=.03), and (3) receipt of tigecycline within 14 days (OR, 4.38, 95% CI, 1.37-17.01, P=.02).

CONCLUSIONS

In hospitalized patients with CRKPs, tigecycline nonsusceptibility was more frequently observed in those admitted from skilled nursing facilities and occurred earlier during hospitalization. Skilled nursing facilities are an important target for interventions to decrease antibacterial resistance to antibiotics of last resort for treatment of CRKPs.

Antibiotic stewardship programmes in intensive care units: Why, how, and where are they leading us

Antibiotic usage and increasing antimicrobial resistance (AMR) mount significant challenges to patient safety and management of the critically ill on intensive care units (ICU). Antibiotic stewardship programmes (ASPs) aim to optimise appropriate antibiotic treatment whilst minimising antibiotic resistance. Different models of ASP in intensive care setting, include “standard” control of antibiotic prescribing such as “de-escalation strategies”through to interventional approaches utilising biomarker-guided antibiotic prescribing. A systematic review of outcomes related studies for ASPs in an ICU setting was conducted. Forty three studies were identified from MEDLINE between 1996 and 2014. Of 34 non-protocolised studies, [1 randomised control trial (RCT), 22 observational and 11 case series], 29 (85%) were positive with respect to one or more outcome: These were the key outcome of reduced antibiotic use, or ICU length of stay, antibiotic resistance, or prescribing cost burden. Limitations of non-standard antibiotic initiation triggers, patient and antibiotic selection bias or baseline demographic variance were identified. All 9 protocolised studies were RCTs, of which 8 were procalcitonin (PCT) guided antibiotic stop/start interventions. Five studies addressed antibiotic escalation, 3 de-escalation and 1 addressed both. Six studies reported positive outcomes for reduced antibiotic use, ICU length of stay or antibiotic resistance. PCT based ASPs are effective as antibiotic-stop (de-escalation) triggers, but not as an escalation trigger alone. PCT has also been effective in reducing antibiotic usage without worsening morbidity or mortality in ventilator associated pulmonary infection. No study has demonstrated survival benefit of ASP. Ongoing challenges to infectious disease management, reported by the World Health Organisation global report 2014, are high AMR to newer antibiotics, and regional knowledge gaps in AMR surveillance. Improved AMR surveillance data, identifying core aspects of successful ASPs that are transferable, and further well-conducted trials will be necessary if ASPs are to be an effective platform for delivering desired patient outcomes and safety through best antibiotic policy.

Factors influencing ceftriaxone use in community-acquired pneumonia: Emergency doctors' perspectives

OBJECTIVE

To explore the perceptions of ED doctors regarding the use of ceftriaxone in patients with community-acquired pneumonia (CAP).

METHODS

Face-to-face interviews were conducted with ED doctors in an Australian tertiary public hospital. A semi-structured interview method was used for collecting data and a framework analysis approach utilised to identify emerging themes regarding the influences on ED prescribers when using ceftriaxone for CAP.

RESULTS

Eight interviews were performed (two consultants, four registrars and two residents). Five main themes emerged as influencing decisions regarding the selection of ceftriaxone for patients with CAP: (i) clinical intuition versus structured evaluation of severity; (ii) clinical uncertainty; (iii) prior experience; (iv) source of guidance; and (v) prescribing etiquette.

CONCLUSION

As most cases of CAP are initially diagnosed and treated empirically in the ED, any interventions that aim to decrease inappropriate use of ceftriaxone for CAP should address the factors identified here that influence ED doctors' prescribing decisions.