The Impact of Clinical Factors and SARS-CoV-2 Variants on Antibody Production in Vaccinated German Healthcare Professionals Infected Either with the Delta or the Omicron Variant

BACKGROUND

The aim of the rapid introduction of vaccines during the COVID-19 pandemic was a reduction in SARS-CoV-2 transmission and a less frequent occurrence of severe COVID-19 courses. Thus, we evaluated COVID-19 severity in vaccinated individuals to examine variant-specific symptom characteristics and their clinical impact on the serological immune response.

METHODS

A total of 185 individuals previously vaccinated against and infected with the SARS-CoV-2 Delta (B.1.617.2) or Omicron (BA.4 and BA.5) variant, were enrolled for anti-SARS-CoV-2 anti-N- and anti-RBD/S1-Ig level detection. A structured survey regarding medical history was conducted.

RESULTS

In 99.5 percent of cases, outpatient treatment was satisfactory. Specific symptoms associated with variants included ageusia and anosmia in patients with Delta infections and throat pain in Omicron infections. Among Delta-infected individuals with specific symptoms, significantly higher levels of anti-N antibodies were observed.

CONCLUSION

Our study identified variant-specific differences in the amount of SARS-CoV-2 antibody production and COVID-19 symptoms. Despite this, vaccinated individuals with Omicron or Delta infections generally experienced mild disease courses. Additionally, asymptomatic individuals exhibit lower anti-SARS-CoV-2 antibody levels, indicating a clinical correlation between disease-specific antibodies and distinct symptoms, particularly in the case of the Delta variant. In follow-up studies, exploring post-COVID syndrome and focusing on cognitive symptoms in the acute phase of Omicron infections is crucial as it has the potential to longitudinally impact the lives of those affected.

Outbreak of SARS-CoV-2 in a geriatric acute-care ward during summer 2023: current aspects of infection control in the postpandemic period

Aim

Management of a SARS-CoV-2 outbreak in geriatric patients, taking into account the transition to the post-pandemic period.

Methods

PCR tests were conducted to identify the scale of infection during the outbreak; no new patients were admitted to the ward until the availability of the PCR results. Based on the results and individual risk assessment, three cohorts were formed and treated as recommended by the RKI. After terminating the admissions stop, new admissions received PCR screening. Contact patients were retested on days 3 and 5. Employees carried out self-monitoring, and if symptoms developed, an antigen test was performed.

Results

Nine of the 11 PCR-positive patients (6m, 5f), median age 85 years, were immunized. Eight patients were symptomatic, ten received antiviral therapy and two required intensive care. Three symptomatic employees had a positive antigen test. Patients without direct contact to the positive cases who initially tested negative and the 16 new admissions with a negative PCR test did not contract COVID-19. Outbreak management ended after 15 days without deaths from COVID-19.

Conclusion

During the outbreak, PCR screening, the temporary stop in new admission until the availability of PCR results, and the risk-adapted cohorting of patients supplemented by consistent PCR tests of new admissions formed the basis for successful outbreak management. Treatment can be made possible despite high vulnerability. Close symptom monitoring and rapid implementation of measures reduce the risk. Repeated PCRs of direct-contact patients on day 3 can warrant pre-emptive antiviral therapy despite being asymptomatic; testing on day 5 makes it possible to shorten preventive isolation measures. The use of protective masks and self-monitoring by employees are fundamental to preventing further infections.

Forecasting local hospital bed demand for COVID-19 using on-request simulations

Accurate forecasting of hospital bed demand is crucial during infectious disease epidemics to avoid overwhelming healthcare facilities. To address this, we developed an intuitive online tool for individual hospitals to forecast COVID-19 bed demand. The tool utilizes local data, including incidence, vaccination, and bed occupancy data, at customizable geographical resolutions. Users can specify their hospital's catchment area and adjust the initial number of COVID-19 occupied beds. We assessed the model's performance by forecasting ICU bed occupancy for several university hospitals and regions in Germany. The model achieves optimal results when the selected catchment area aligns with the hospital's local catchment. While expanding the catchment area reduces accuracy, it improves precision. However, forecasting performance diminishes during epidemic turning points. Incorporating variants of concern slightly decreases precision around turning points but does not significantly impact overall bed occupancy results. Our study highlights the significance of using local data for epidemic forecasts. Forecasts based on the hospital's specific catchment area outperform those relying on national or state-level data, striking a better balance between accuracy and precision. These hospital-specific bed demand forecasts offer valuable insights for hospital planning, such as adjusting elective surgeries to create additional bed capacity promptly.

A case series of severe breakthrough infections observed in nine patients with COVID-19 in a southwestern German university hospital

Purpose

Vaccination is the key element for protection against COVID-19. Increased vaccination breakthroughs raise the question of whether additional prevention is necessary in case of individual risk factors for a severe course with hospitalization or death despite vaccination.

Methods

Since July 13, 2021, there is an extended reporting requirement by German law. We analyzed our hospitalized patients with vaccine breakthrough infection during the first 8 weeks.

Results

Nine of 67 patients (13.4%) hospitalized for COVID-19 (median age 75 years) were fully vaccinated. Five of these patients received intensive care; two patients died. All had received two doses of BNT162b2 vaccines (Pfizer-BioNTech). There was a median of 99 days between complete immunization and symptom onset. All patients suffered from ≥ three comorbidities. Six patients (66.7%) showed a negative Anti-SARS-CoV-2-N titer at the time of vaccine breakthrough, five of these also had Anti-SARS-CoV-2-S titers < 100 U/ml. All determinable cases were Delta variant B.1.617.2.

Conclusion

Advanced age, underlying cardiorespiratory disease, and the Delta variant of SARS-CoV-2 were associated with hospitalization of our patients, suffering from vaccine breakthrough infection. Avoidance of face masks, lack of immunization of close contacts, and travel to high-risk areas have been observed as modifiable behavioural circumstances. Consistent personal protective measures, vaccination of close caregivers, and increased awareness might be effective measures in addition to COVID-19 booster vaccination for patients at a high risk to suffer a severe course of infection.

Antibiotic Stewardship and Therapeutic Drug Monitoring of β-Lactam Antibiotics: Is There a Link? An Opinion Paper

PURPOSE

In critically ill patients, changes in the pharmacokinetics (PK) of β-lactams can lead to significant variations in serum concentrations, with possibly detrimental effects on outcomes. The utilization of individually calculated doses, extended infusion regimen, and therapeutic drug monitoring (TDM)-guided dose adjustments can mitigate the PK changes and help to achieve and attain an individual PK target.

METHODS

We reviewed relevant literature from 2004 to 2021 using 4 search engines (PubMed, Web of Science, Scopus, and Google Scholar). Unpublished clinical data were also examined.

RESULTS

TDM-guided, individualized dosing strategies facilitated PK target attainment and improved patient outcomes. TDM-guided therapy is a core concept of individualized dosing that increases PK target attainment and identifies possible toxic β-lactam concentrations.

CONCLUSIONS

Individualized dosing and TDM facilitate the rational use of β-lactams and are integral for antibiotic stewardship interventions in critical care, affording the optimal exposure of both pathogen and drugs, along with enhanced treatment efficacy and reduced emergence of antimicrobial resistance.

Direct-PCR from rectal swabs and environmental reservoirs: A fast and efficient alternative to detect blaOXA-48 carbapenemase genes in an Enterobacter cloacae outbreak setting

Carbapenemase-producing bacteria are a risk factor in clinical settings worldwide. The aim of the study was to accelerate the time to results during an outbreak situation with bla_OXA-48-positive Enterobacter cloacae by using a real-time multiplex quantitative PCR (qPCR) directly on rectal swab specimens and on wastewater samples to detect carbapenemase-producing bacteria. Thus, we analyzed 681 rectal swabs and 947 environmental samples during a five-month period by qPCR and compared the results to culture screening. The qPCR showed a sensitivity of 100% by testing directly from rectal swabs and was in ten cases more sensitive than the culture-based methods. Environmental screening for bla_OXA-48-carbapenemase genes by qPCR revealed reservoirs of different carbapenemase genes that are potential sources of transmission and might lead to new outbreaks. The rapid identification of patients colonized with those isolates and screening of the hospital environment is essential for earlier patient treatment and eliminating potential sources of nosocomial infections.

Genomic Investigation and Successful Containment of an Intermittent Common Source Outbreak of OXA-48-Producing Enterobacter cloacae Related to Hospital Shower Drains

The hospital environment has been reported as a source of transmission events and outbreaks of carbapenemase-producing Enterobacterales. Interconnected plumbing systems and the microbial diversity in these reservoirs pose a challenge for outbreak investigation and control. A total of 133 clinical and environmental OXA-48-producing Enterobacter cloacae isolates collected between 2015 and 2021 were characterized by whole-genome sequencing (WGS) to investigate a prolonged intermittent outbreak involving 41 patients in the hematological unit. A mock-shower experiment was performed to investigate the possible acquisition route. WGS indicated the hospital water environmental reservoir as the most likely source of the outbreak. The lack of diversity of the blaOXA-48-like harbouring plasmids was a challenge for data interpretation. The detection of blaOXA-48-like-harboring E. cloacae strains in the shower area after the mock-shower experiment provided strong evidence that showering is the most likely route of acquisition. Initially, in 20 out of 38 patient rooms, wastewater traps and drains were contaminated with OXA-48-positive E. cloacae. Continuous decontamination using 25% acetic acid three times weekly was effective in reducing the trap/drain positivity in monthly environmental screening but not in reducing new acquisitions. However, the installation of removable custom-made shower tubs did prevent new acquisitions over a subsequent 12-month observation period. In the present study, continuous decontamination was effective in reducing the bacterial burden in the nosocomial reservoirs but was not sufficient to prevent environment-to-patient transmission in the long term. Construction interventions may be necessary for successful infection prevention and control. IMPORTANCE The hospital water environment can be a reservoir for a multiward outbreak, leading to acquisitions or transmissions of multidrug-resistant organisms in a hospital setting. The majority of Gram-negative bacteria are able to build biofilms and persist in the hospital plumbing system over a long period of time. The elimination of the reservoir is essential to prevent further transmission and spread, but proposed decontamination regimens, e.g., using acetic acid, can only suppress but not fully eliminate the environmental reservoir. In this study, we demonstrated that colonization with multidrug-resistant organisms can be acquired by showering in showers with contaminated water traps and drains. A construction intervention by installing removable and autoclavable shower inserts to avoid sink contact during showering was effective in containing this outbreak and may be a viable alternative infection prevention and control measure in outbreak situations involving contaminated shower drains and water traps.

The Impact of Discontinuing Contact Precautions and Enforcement of Basic Hygiene Measures on Nosocomial Vancomycin-Resistant Enterococcus faecium Transmission

OBJECTIVES

Vancomycin-resistant Enterococcus faecium (VREfm) has emerged as a pathogen of major public health concern. Although definitive evidence is lacking, contact precautions have been a crucial element in infection prevention and control (IPC) strategies designed to limit nosocomial VRE transmissions. This study investigates the effect of discontinuing contact precautions while enforcing basic hygiene measures, including hand hygiene, environmental cleaning, and antiseptic body washing, for VRE patients at ICUs on prevention of nosocomial VRE transmission causing bacteraemia.

METHODS

Contact precaution was discontinued in January 2018. A total of 96 VREfm isolates from 61 ICU patients with VREfm bacteraemia and/or colonization from 8 ICUs in 2016 and 2019 in a tertiary care hospital were characterized by whole genome sequenicng. VRE transmission was investigated using patient movement data and admission screening for reliable identification of nosocomial acquisition.

RESULTS

Discontinuation of contact precautions did not increase VREfm transmission events (8 in 2016 vs 1 in 2019). While the rate of endogenous VREfm was similar in both years (38% vs 31%), the number of non-colonized patients prior to VREfm bacteraemia was 16 (16/29; 55%) in 2019, which was significantly higher than in 2016 (8/32; 25%). The mean incidence density for VREfm bacteraemia was similar for both years; 0.26 versus 0.31 per 1000 patient days in 2016 and 2019, respectively.

CONCLUSION

Our data suggest that discontinuation of contact precaution, while enforcing the basic hygiene measures did not lead to an increase of nosocomial bloodstream infection rates due to transmissions of VREfm in hyperendemic ICU settings.

Assessing the clinical accuracy of a hand hygiene system: Learnings from a validation study

There is a need to establish validation standards that allow for comparison of automated hand hygiene systems. To assess the accuracy of an innovative monitoring tool (Sani nudge), 2 test nurses performed clinical standard tasks while being observed by 2 infection preventionists. Data from the direct observations were compared with data obtained from the hand hygiene system (Sani nudge) using an independent-event approach. We identified 54 true-positive events (100% system accuracy) and 4 true-negative events (100% system accuracy). No false-positive or false-negative events were identified. We found this approach to be feasible and clinically useful to validate hand hygiene systems in the future.

[Evaluation of a SARS-CoV-2 test strategy in a southwestern university hospital at the beginning of the COVID-19 pandemic]

Hintergrund

Zu Beginn der COVID-19-Pandemie in Deutschland veröffentlichte das Robert Koch-Institut (RKI) Orientierungshilfen für eine bedarfsadaptierte und zielgerichtete Teststrategie auf SARS-CoV‑2. In der Universitätsmedizin Mannheim (UMM) wurde von Beginn an eine RKI-konforme Teststrategie, basierend auf den RKI-Orientierungshilfen angewendet. Ziel dieser Arbeit ist es, zu klären, ob sich diese RKI-konforme Teststrategie als lohnenswert erwiesen hat.

Material und Methoden

Es erfolgte eine retrospektive Auswertung aller SARS-CoV-2-Untersuchungen im Zeitraum 26.02.–06.04.2020. Mithilfe der Adressinformationen der getesteten Personen erfolgte zudem eine Geovisualisierung der SARS-CoV-2-Testhäufigkeiten und der positiven Testergebnisse im Stadtgebiet Mannheim.

Ergebnisse

Der Anteil SARS-CoV-2-positiver Befunde bei den diagnostischen Proben (n = 2808) lag durchschnittlich bei 7 %. Ein Mitarbeiterscreening (n = 448) blieb ohne positiven Befund. Es erfolgte lediglich ein nosokomialer SARS-CoV-2-Nachweis, Ausbruchsgeschehen gab es nicht. Die Geovisualisierung zeigte innerhalb des Untersuchungszeitraumes eine Verschiebung der Testhäufigkeiten und der lokalen Häufigkeit positiver SARS-CoV-2-Befunde im Stadtgebiet Mannheim.

Diskussion

Die festgelegte RKI-konforme Teststrategie führte sowohl zu einem stabilen Anteil positiver Ergebnisse als auch zu einer bedarfsadaptierten Anpassung der Testkapazitäten. Dadurch hat sich diese Strategie unter Praxisbedingungen aus infektionshygienischer und -präventiver Sicht als effektiv erwiesen. Geovisualisierungen können dabei helfen, innerhalb eines Stadtgebietes Verschiebungen von Infektionsherden deutlich zu machen, was im Sinne gezielter infektionspräventiver Maßnahmen (z. B. Impfkampagnen) sinnvoll eingesetzt werden kann.

[New antibiotics for severe infections due to multidrug-resistant pathogens : Definitive treatment and escalation]

Multidrug-resistant pathogens often lead to treatment failure of antimicrobial regimens. After a period of imbalance between the occurrence/spread of resistance mechanisms and the development of new substances, some new substances have meanwhile been approved and many more are currently undergoing clinical testing. They are particularly effective against specific resistance mechanisms/pathogens and should be preserved for definitive treatment of an isolated pathogen. In the absence of alternatives reserve antibiotics, such as aztreonam and colistin have experienced a renaissance. They are again used in special infection scenarios and clinically tested in combination with new substances. Despite the introduction and development of new substances the building of resistance will at some time also render these (at least partially) ineffective. Therefore, their implementation must be carried out according to the antibiotic or infectious diseases stewardship.

Soluble intercellular adhesion molecule (ICAM)-1 detects invasive fungal infections in patients following liver transplantation

PURPOSE

Despite antifungal prophylaxis, liver transplanted patients are endangered by invasive fungal infections (IFI). Routinely used microbiological procedures are hallmarked by significant weaknesses, which may lead to a delay in antifungal treatment.

METHODS

Culture-based fungal findings, routinely used biomarkers of infection/inflammation (e.g., procalcitonin or C-reactive protein), as well as corresponding plasma concentrations of soluble Intercellular Adhesion Molecule (ICAM)-1 were analysed in 93 patients during a period of 28 days following liver transplantation (LTX).

RESULTS

Plasmatic sICAM-1 was significantly elevated in patients affected by an IFI within the first 28 days in comparison to fungally colonised or unobtrusive LTX patients. sICAM-1 might therefore be helpful for the identification of IFI patients after LTX (e.g., Receiver Operating Characteristic (ROC)-Area Under the Curve (AUC): 0.714 at 14d after LTX). The diagnostic performance of sICAM-1 was further improved by its combined use with different other IFI biomarkers (e.g., midregional proadrenomedullin).

CONCLUSION

The diagnostic deficiencies of routinely used microbiological procedures for IFI detection in patients after LTX may be reduced by plasmatic sICAM-1 measurements. Clinical Trial Notation. German Clinical Trials Register: DRKS00005480.

Low prevalence of combined linezolid- and vancomycin-resistant Enterococcus faecium from hospital admission screening in an endemic region in Germany

BACKGROUND

The emergence and spread of linezolid and combined linezolid/vancomycin resistance in Enterococcus faecium (LVRE) is a major therapeutic challenge. Due to the unavailability of standardized selective culture media for LVRE screening, the detection of LVRE is laborious and costly. Systematic data on LVRE prevalence are scarce, and therefore, supportive evidence for the correct implementation of preemptive strategies is lacking.

OBJECTIVE

We investigated the prevalence of LVRE in a vancomycin-resistant enterococci (VRE) endemic area in Germany in admission screening of high-risk patients for multidrug-resistant organisms to assess the necessity of LVRE screening.

METHODS

We performed phenotypic testing for linezolid susceptibility in all patients (n = 2572) admitted to our hospital in the months of January, April, July and October 2018 with a positive VRE culture in their rectal admission screening swab. Eight isolates from seven patients with LVRE colonization were characterized by whole genome sequencing.

RESULTS

Twenty-eight percent (712/2572) of screened patients were colonized by VRE. Seventy percent (497/712) of the isolates were available for testing and whole genome sequencing. A total of 1.4% (7/497) of VRE were LVRE, predominantly due to mutations of 23S rRNA. optrA, poxtA or cfr genes were not detected. Patients with LVRE colonization did not develop LVRE infections during their stay.

CONCLUSION

LVRE prevalence was low, and there was no evidence for the dissemination of linezolid resistance genes. Due to the low prevalence and the low risk of infection due to endogenous LVRE, we do not see the immediate necessity to introduce routine LVRE screening in our hospital.

[Urology in the corona-virus pandemic-a guideline 4/20]

Die Corona-Virus-Pandemie stellt die Gesundheitssysteme weltweit vor eine große Herausforderung. Für die Urologie gilt es, den Ausbau der Strukturen zur Behandlung der unter COVID-19 („corona virus disease 2019“) leidenden Patienten bestmöglich zu unterstützen. Gleichzeitig muss es das Ziel sein, eine angemessene gesundheitliche Versorgung von urologischen Notfällen und dringlichen urologischen Behandlungen auch während der Pandemie möglichst zu gewährleisten. Hierzu müssen Patienten individuell priorisiert, alternative Therapiekonzepte erwogen und regionale und überregionale Kooperationen genutzt werden. Den Praxen kommt bei der Versorgung, Sichtung und Koordination urologischer Notfälle eine große Bedeutung zu. Urologische Kliniken müssen sich durch geeignete Maßnahmen wie dem Schaffen eines separaten, entsprechend ausgestatteten Notfalloperationssaals darauf vorbereiten, Notfalloperationen und Interventionen an SARS-CoV-2-positiven Patienten („severe acute respiratory syndrome corona virus 2“) durchzuführen und Hygienemaßnahmen zum Schutz der Mitarbeiter festlegen.

Nasal colonization with Staphylococcus aureus is a risk factor for ventricular assist device infection in the first year after implantation: A prospective, single-centre, cohort study

OBJECTIVES

To assess, whether S. aureus nasal colonization is a risk factor for infections in patients with durable ventricular assist device (VAD).

METHODS

Prospective, single-centre, cohort study (i) ascertaining S. aureus nasal colonization status of patients admitted for VAD-implantation and detecting time to first episode of VAD-specific or -related infection according to International Society for Heart and Lung Transplantation criteria during follow-up and (ii) comparing whole genomes of S. aureus from baseline colonization and later infection.

RESULTS

Among 49 patients (17 colonized, 32 non-colonized), S. aureus VAD-infections occurred with long latency after implantation (inter quartile range 76-217 days), but occurred earlier (log-rank test P = 0.006) and were more common (9/17, 52.9% vs. 4/32, 12.5%, P = 0.005; incidence rates 2.81 vs. 0.61/1000 patient days; incidence rate ratio 4.65, 95% confidence interval 1.30-20.65, P = 0.009) among those nasally colonized with S. aureus before implantation. We found a similar but less pronounced effect of colonization status when analysing its effect on all types of VAD-infections (10/17, 58.8% vs. 7/32, 21.9%, P = 0.01). These findings remained robust when adjusting for potential confounders and restricting the analysis to 'proven infections'. 75% (6/8) of paired S. aureus samples from colonization and VAD-infection showed concordant whole genomes.

CONCLUSIONS

In patients with durable VAD, S. aureus nasal colonization is a source of endogenous infection, often occurring months after device-implantation and affecting mostly the driveline. Hygiene measures interrupting the endogenous route of transmission in VAD-patients colonized with S. aureus long-term may about half the burden of infections and require clinical scrutiny.

Does vancomycin resistance increase mortality in Enterococcus faecium bacteraemia after orthotopic liver transplantation? A retrospective study

BACKGROUND

The relevance of vancomycin resistance in enterococcal blood stream infections (BSI) is still controversial. Aim of this study was to outline the effect of vancomycin resistance of Enterococcus faecium on the outcome of patients with BSI after orthotopic liver transplantation (OLT).

METHODS

The outcome of OLT recipients developing BSI with vancomycin-resistant (VRE) versus vancomycin-susceptible Enterococcus faecium (VSE) was compared based on data extraction from medical records. Multivariate regression analyses identified risk factors for mortality and unfavourable outcomes (defined as death or prolonged intensive care stay) after 30 and 90 days.

RESULTS

Mortality was similar between VRE- (n = 39) and VSE- (n = 138) group after 30 (p = 0.44) or 90 days (p = 0.39). Comparable results occurred regarding unfavourable outcomes. Mean SOFA_Non-GCS score during the 7-day-period before BSI onset was the independent predictor for mortality at both timepoints (HR 1.32; CI 1.14-1.53; and HR 1.18; CI 1.08-1.28). Timely appropriate antibiotic therapy, recent ICU stay and vancomycin resistance did not affect outcome after adjusting for confounders.

CONCLUSION

Vancomycin resistance did not influence outcome among patients with Enterococcus faecium bacteraemia after OLT. Only underlying severity of disease predicted poor outcome among this homogenous patient population.

TRIAL REGISTRATION

This study was registered at the German clinical trials register (DRKS-ID: DRKS00013285).

Multidrug-Resistant Bacteria and Disease Progression in Patients with End-Stage Liver Disease and after Liver Transplantation

BACKGROUND

Multidrug-resistant (MDR) pathogens represent an emerging challenge in end-stage liver disease and in liver transplant recipients.

METHODS

We evaluated the impact of MDR bacteria upon clinical outcomes in patients with end-stage liver disease (n = 777) at the time of enrollment on the liver transplant (LTx) waiting list, after first LTx (n = 645), and after second LTx (n = 128).

RESULTS

Colonization/infection with MDR bacteria was present in 72/777 patients on the waiting list, in 98/645 patients at first LTx, and in 46/128 patients at second LTx. While on the LTx waiting list, the time until first hydropic decompensation (p = 0.021), hepatic encephalopathy (p < 0.001) and hepatorenal syndrome (p < 0.001) was reduced in the presence of MDR bacteria, which remained an independent risk factor of poor survival in multivariate analysis (p < 0.001). Following first and second liver transplant, MDR bacteria were associated with an increased risk of infection-related deaths (first LTx: p < 0.001; second LTx: p = 0.037) and reduced actuarial survival (first LTx: p < 0.001; second LTx: p = 0.046).

CONCLUSIONS

We showed that MDR pathogens are associated with poor outcomes before, after first and after recurrent LTx.

[Diagnostic Approaches in Sepsis - Part 1: General Diagnostic Principles, Focus Identification and Source Control]

Sepsis and septic shock represent medical emergencies with persistently high mortality rates. According to the lately revised Surviving Sepsis Campaign (SSC) guidelines, focus identification/pathogen detection and the initial administration of broad-spectrum antibiotics are to be secluded within one hour after recognition of the symptoms of sepsis. However, there is dispute concerning the so called hour-1 bundle. Being a core aspect of focus identification, imaging modalities mainly depend on the suspected site of infection and the individual patient. Contrast agent-enhanced computed tomography (CT) is the modality usually used in critically ill patients. The microbiological pathogen detection still largely remains culture-based. This emphasizes the significance of microbiological specimen obtained from easily accessible body compartments and at least 2 blood culture sets. If possible, blood cultures should be drawn prior to antibiotic administration. Intraoperatively obtained swabs of otherwise sterile body compartments are of utmost importance with regard to microbiological pathogen detection. Catheters and implanted medical devices (i.e. cardiac pacemakers or defibrillators) suspicious of infection should be explanted and sent in for microbiological workup as soon as possible. All necessary source control measures should be realized as soon as medically possible but at least within 6 - (12) hours after the onset of symptoms. There is no specific biomarker for sepsis so far. Procalcitonin (PCT) and C-reactive protein (CRP) are crucial biomarkers in terms of infectious disease management and guidance of antimicrobial therapy in the ICU. Positive clinical trials showed that biomarkers like the midregional pro-adrenomedullin (MR-proADM) or presepsin might be promising candidates in the diagnosis of sepsis in the future. As an important marker of microcirculatory failure and disrupted cell metabolism, lactate serum concentrations (and lactate-clearance, respectively) are of prognostic value in septic patients.

[Diagnostic Approaches in Sepsis - Part 2: Pathogen Detection]

Despite the dissemination of innovative, molecular biology-based and commercially available devices for pathogen detection, culture-based methods with susceptibility testing remain the key principles for guiding antimicrobial treatment of patients suffering from sepsis or septic shock on the ICU. Culture-based methods are able to facilitate pathogen detection from a diversity of specimen (respiratory secretion, intraoperatively obtained smears, aspirates, and so forth). However, the latency from obtainment of the specimen up to pathogen detection with susceptibility testing is a major disadvantage of culture-based methods in critical illness. Molecular biology-based methods like Polymerase Chain Reaction (PCR) and especially Next-Generation Sequencing (NGS) based methods promise faster pathogen and resistance detection, but are not used in clinical routine yet. With more clinical trials to come, these innovative diagnostic tools may have the potential to lead to a paradigm shift within the context of pathogen identification in sepsis.

Tigecycline in critically ill patients on continuous renal replacement therapy: a population pharmacokinetic study

Background

Tigecycline is a vital antibiotic treatment option for infections caused by multiresistant bacteria in the intensive care unit (ICU). Acute kidney injury (AKI) is a common complication in the ICU requiring continuous renal replacement therapy (CRRT), but pharmacokinetic data for tigecycline in patients receiving CRRT are lacking.

Methods

Eleven patients mainly with intra-abdominal infections receiving either continuous veno-venous hemodialysis (CVVHD, n = 8) or hemodiafiltration (CVVHDF, n = 3) were enrolled, and plasma as well as effluent samples were collected according to a rich sampling schedule. Total and free tigecycline was determined by ultrafiltration and high-performance liquid chromatography (HPLC)-UV. Population pharmacokinetic modeling using NONMEM® 7.4 was used to determine the pharmacokinetic parameters as well as the clearance of CVVHD and CVVHDF. Pharmacokinetic/pharmacodynamic target attainment analyses were performed to explore the potential need for dose adjustments of tigecycline in CRRT.

Results

A two-compartment population pharmacokinetic (PK) model was suitable to simultaneously describe the plasma PK and effluent measurements of tigecycline. Tigecycline dialysability was high, as indicated by the high mean saturation coefficients of 0.79 and 0.90 for CVVHD and CVVHDF, respectively, and in range of the concentration-dependent unbound fraction of tigecycline (45–94%). However, the contribution of CRRT to tigecycline clearance (CL) was only moderate (CL_CVVHD: 1.69 L/h, CL_CVVHDF: 2.71 L/h) in comparison with CL_body (physiological part of the total clearance) of 18.3 L/h. Bilirubin was identified as a covariate on CL_body in our collective, reducing the observed interindividual variability on CL_body from 58.6% to 43.6%. The probability of target attainment under CRRT for abdominal infections was ≥ 0.88 for minimal inhibitory concentration (MIC) values ≤ 0.5 mg/L and similar to patients without AKI.

Conclusions

Despite high dialysability, dialysis clearance displayed only a minor contribution to tigecycline elimination, being in the range of renal elimination in patients without AKI. No dose adjustment of tigecycline seems necessary in CRRT.

Trial registration

EudraCT, 2012–005617-39. Registered on 7 August 2013.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2278-4) contains supplementary material, which is available to authorized users.

Postoperative pancreatic fistula: Microbial growth determines outcome

BACKGROUND

Postoperative pancreatic fistula is a dangerous complication in pancreatic surgery. This study assessed the impact of microbiologic pathogens detected in postoperative pancreatic fistula on clinical outcomes after partial pancreatoduodenectomy and distal pancreatectomy.

METHODS

Microorganisms in postoperative pancreatic fistula were identified by microbiologic analyses from abdominal drains or intraoperative swabs during relaparotomy. Demographic, operative, and microbiologic data, as well as postoperative outcomes were examined.

RESULTS

Of 2,752 patients undergoing partial pancreatoduodenectomy and distal pancreatectomy, 256 patients with clinically relevant postoperative pancreatic fistula (International Study Group of Pancreatic Surgery [ISGPS] grades B and C) were identified (9.3%) and microbiologic cultures were positive in 210 patients (82.0%), with a higher rate after partial pancreatoduodenectomy (95.8%) than after distal pancreatectomy (64.3%; P < .001). Microbiologic spectra differed distinctively between partial pancreatoduodenectomy and distal pancreatectomy. Detection of microorganisms in postoperative pancreatic fistula resulted in a higher morbidity and mortality, including postpancreatectomy hemorrhage (42.4% vs 21.7%; P = .009), sepsis (38.1% vs 6.5%; P < .001), wound infection (30.0% vs 6.5%; P = .001), reoperation (48.1% vs 10.9%; P < .001), hospital stay (median 42 vs 26 days; P < .001), and overall 90-day mortality (19.5% vs 4.3%; P = .013) and was identified as an independent risk factor for sepsis, wound infection, and reoperation in the multivariate analysis.

CONCLUSION

Detection of microorganisms in postoperative pancreatic fistula is frequent after pancreatic resection and indicates a turning point in the development of postoperative pancreatic fistula into a life-threatening condition. Whether early anti-infective therapy in combination with interventional measures or a surgical reintervention are warranted, has yet to be elucidated.

[Bacterial sepsis : Diagnostics and calculated antibiotic therapy]

The mortality of patients with sepsis and septic shock is still unacceptably high. An effective antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed focus and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account for selection of anti-infection treatment. Many pathophysiological alterations influence the pharmacokinetics of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of beta-lactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM but for continuous infusion TDM is basically necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug resistant pathogens (MDR) in the intensive care unit. For effective treatment antibiotic stewardship teams (ABS team) are becoming more established. Interdisciplinary cooperation of the ABS team with infectiologists, microbiologists and clinical pharmacists leads not only to a rational administration of antibiotics but also has a positive influence on the outcome. The gold standards for pathogen detection are still culture-based detection and microbiological resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction (PCR)-based procedures for pathogen identification and resistance determination, are currently only an adjunct to routine sepsis diagnostics due to the limited number of studies, high costs and limited availability. In complicated septic courses with multiple anti-infective treatment or recurrent sepsis, PCR-based procedures can be used in addition to therapy monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation).

Bacterial and viral contamination of breathing circuits after extended use - an aspect of patient safety?

BACKGROUND

In the past, anaesthetic breathing circuits were identified as a source of pathogen transmission. It is still debated, whether breathing circuits combined with breathing system filters can be safely used for more than 1 day. The aim of this study was to evaluate the transmission risk of bacteria and also viruses via breathing circuits after extended use.

METHODS

The inner and outer surface of 102 breathing circuits used for 1 day and of 101 circuits used for 7 days were examined for bacteria and viruses. Additionally, 10 and 20 breathing circuits each were examined after use on patients with pulmonary virus infection and with multidrug-resistant organism (MDRO) colonisation/infection respectively. Bacteria were detected by standard microbiological procedures; PCR techniques were applied for herpes simplex virus, cytomegalovirus, influenza, parainfluenza and respiratory syncytial virus.

RESULTS

Endoluminal bacterial contamination of breathing circuits remained unchanged after 7-day vs. 1-day use (5.9% vs. 7.8%) [CI95%: -0.0886-0.0506, pnon-inferiority 0.0260]. Only outside surface contamination with bacteria belonging to environmental species or human flora increased (16.8 vs. 6.9%) [CI 95%: 0.0118 - 0.1876, pnon-inferiority 0.8660]. Viruses occurred on the patient side, but not in breathing circuits. No MDRO occurred in the 20 circuits after use on patients harbouring such germs.

CONCLUSION

Endoluminal contamination of breathing circuits with bacteria did not increase after extended use. No viruses were detected in the breathing circuits using filters. Based on our results, the extended use of ABC without exceptions appears safe, if a high level of anaesthesia workplace cleaning is secured.

Heart transplantation as salvage therapy for progressive prosthetic valve endocarditis due to methicillin-resistant Staphylococcus epidermidis (MRSE)

Background

Prosthetic valve endocarditis (PVE) has the highest in-hospital mortality among all cases of infective endocarditis (IE), it is estimated at about 40 %. Orthotopic heart transplantation (OHT) as a measure of last resort, may be considered in selected cases where repeated surgical procedures and conservative efforts have failed to eradicate persistent or recurrent IE. Only few clinical data are available regarding this rare indication for OHT, since active IE has traditionally been considered as a contraindication for OHT.

Case presentation

We report on a 55 year old male patient who underwent prosthetic valve replacement with a mechanical valved conduit ten years ago and developed now persistent PVE with severe complications due to methicillin-resistant Staphylococcus epidermidis (MRSE). Repeated surgical procedures and conservative efforts have failed to eradicate the pathogen. Regarding the lack of curative options, salvage OHT was discussed as a measure of last resort. 28 months after the first diagnosis of PVE, the patient was successfully transplanted and is now doing well under close follow-up (6 months post-OHT).

Conclusions

PVE remains a challenging condition regarding diagnosis and treatment. The presented case underscores the urgent need for an integrated and multidisciplinary approach to patients with suspected and definitive IE - especially in PVE. OHT might be a feasible measure of last resort in selected patients with IE. Our case report adds published clinical experience to this rarely performed procedure and consolidates previous findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-016-0505-0) contains supplementary material, which is available to authorized users.

Device-related infections in long-term healthcare facilities: the challenge of prevention

The world is aging and the number of elderly multimorbid patients is steadily increasing. The limited numbers of acute care beds in hospitals, in addition to the need to reduce costs, has led to the introduction of efficient discharge policies, which in turn have increased demand for beds in nursing homes and long-term care facilities (LTCFs). As a consequence, the number of postacute LTCF residents is rising, as is the number of residents requiring complex medical care delivered by use of indwelling medical devices. These devices place patients at a heightened risk for infection. Furthermore, infection control resources in LTCFs are often limited. This article reviews the preventive measures that should be taken in LTCFs to reduce the risk of device-related infections.

Detection of pneumonia associated pathogens using a prototype multiplexed pneumonia test in hospitalized patients with severe pneumonia

Severe pneumonia remains an important cause of morbidity and mortality. Polymerase chain reaction (PCR) has been shown to be more sensitive than current standard microbiological methods – particularly in patients with prior antibiotic treatment – and therefore, may improve the accuracy of microbiological diagnosis for hospitalized patients with pneumonia. Conventional detection techniques and multiplex PCR for 14 typical bacterial pneumonia-associated pathogens were performed on respiratory samples collected from adult hospitalized patients enrolled in a prospective multi-center study. Patients were enrolled from March until September 2012. A total of 739 fresh, native samples were eligible for analysis, of which 75 were sputa, 421 aspirates, and 234 bronchial lavages. 276 pathogens were detected by microbiology for which a valid PCR result was generated (positive or negative detection result by Curetis prototype system). Among these, 120 were identified by the prototype assay, 50 pathogens were not detected. Overall performance of the prototype for pathogen identification was 70.6% sensitivity (95% confidence interval (CI) lower bound: 63.3%, upper bound: 76.9%) and 95.2% specificity (95% CI lower bound: 94.6%, upper bound: 95.7%). Based on the study results, device cut-off settings were adjusted for future series production. The overall performance with the settings of the CE series production devices was 78.7% sensitivity (95% CI lower bound: 72.1%) and 96.6% specificity (95% CI lower bound: 96.1%). Time to result was 5.2 hours (median) for the prototype test and 43.5 h for standard-of-care. The Pneumonia Application provides a rapid and moderately sensitive assay for the detection of pneumonia-causing pathogens with minimal hands-on time.

Trial Registration

Deutsches Register Klinischer Studien (DRKS) DRKS00005684

Population pharmacokinetics and pharmacodynamic evaluation of intravenous and enteral moxifloxacin in surgical intensive care unit patients

OBJECTIVES

To describe the plasma concentration-time profile of moxifloxacin after intravenous and enteral administration in intensive care unit (ICU) patients and to provide a pharmacodynamic (PD) evaluation with regard to pneumonia.

PATIENTS AND METHODS

Twenty-five adult patients from a cardiothoracic/mixed surgical ICU were enrolled. Moxifloxacin was given as a standard dose (400 mg once daily). Therapy was successfully switched to enteral administration on day 5 in 16 patients. A rich data sampling schedule was performed after intravenous (day 4) and enteral (day 8) administration. Moxifloxacin concentrations were analysed by HPLC. A population pharmacokinetic (PK) model was developed using NONMEM VII. Simulated concentration-time profiles were evaluated for their probability of attaining PK/PD target values relevant for community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP).

RESULTS

A linear-elimination two-compartment model described the data adequately. Parameter estimates (coefficient of variation of inter-individual variability) were: absorption rate constant, 1.09/h (135%); enteral bioavailability, 76% (20.0%); central volume of distribution, 55.6 L; peripheral volume of distribution, 59.6 L (15.3%); inter-compartmental clearance, 47.7 L/h; and clearance, 11.3 L/h (23.7%). Both intravenously and enterally administered standard-dose moxifloxacin reliably attained the PK/PD target values for pathogens with MICs ≤ 0.25 mg/L for CAP and ≤ 0.125 mg/L for HAP.

CONCLUSIONS

Drug exposure to moxifloxacin in ICU patients was more variable than in healthy volunteers. The standard dosing provides sufficient drug exposure for treatment of CAP but for HAP it does so only when a highly susceptible pathogen is present. Intravenous/enteral sequential therapy may be considered for cautiously selected cases in ICU patients.

Spontaneous hepatic rupture in amyloidosis - report of a case

In systemic amyloidosis spontaneous rupture of the liver is a rare complication. Here we report on a patient with unrecognized systemic amyloidosis who presented to an outside hospital with unspecific abdominal pain. Under the signs of a hemorrhagic shock, distended abdomen and intraabdominal bleeding a laparotomy was performed. Due to uncontrollable hemorrhage of the ruptured right liver lobe a packing was performed. After being transferred to the reporting institution a CT scan was performed showing a grade IV laceration of the right liver. Therefore a transarterial embolization of the right hepatic artery was carried out. The following day an infection of the abdominal cavity and the abdominal wall with gas-producing bacteria was noticed and a relaparotomy, necrectomy and repacking due to diffuse bleeding were performed. The situation deteriorated and at the second relaparotomy the following day an almost completely necrotic liver was found. The patient deceased the following day. Life-threatening spontaneous liver rupture due to systemic amyloidosis might only successfully be cured by high urgency liver transplantation as presented in the literature. However, in two published cases interventional therapy by embolization of bleeding vessels has saved patients' life.

[Current aspects of sepsis caused by bacterial translocation]

Bacterial translocation has been put forward as a concept to explain sepsis without an infectious focus, but it has been difficult to prove in humans. Dysfunction of the intestinal barrier, which is composed of physical, biochemical and immunological factors, is the pathophysiological prerequisite for bacterial translocation. Recent findings indicate that not only viable bacteria but also pathogen associated molecular patterns may translocate and cause sepsis. Molecular detection methods for bacteria or their components have been developed to address these new concepts, but they have not yet become widely available. Specific therapeutic interventions within the sepsis cascades and signaling pathways of the innate and specific immune system so far have not been successful. Selective oral decontamination (SOD) und selective digestive tract decontamination (SDD) are efficacious prophylactic measures against nosocomial septic complications. An increased incidence of resistant pathogens has not been encountered. The use of probiotics as prophylaxis against septic complications is controversial and has led in some studies to a worse prognosis.

Assessment of hemodynamic efficacy and safety of 6% hydroxyethylstarch 130/0.4 vs. 0.9% NaCl fluid replacement in patients with severe sepsis: the CRYSTMAS study

Introduction

Inadequate initial treatment and delayed hemodynamic stabilization (HDS) may be associated with increased risk of death in severe sepsis patients.

Methods

In order to compare the hemodynamic efficacy and safety of 6% HES 130/0.4 and NaCl 0.9% for HDS in patients with severe sepsis, we designed a prospective, multicenter, active-controlled, double-blind, randomized study in intensive care units.

Results

174 out of 196 patients reached HDS (88 and 86 patients for HES and NaCl, respectively). Significantly less HES was used to reach HDS vs. NaCl (1,379 ±886 ml in the HES group and 1,709 ±1,164 ml in the NaCl group (mean difference = -331± 1,033, 95% CI -640 to -21, P = 0.0185). Time to reach HDS was 11.8 10.1 hours vs. 14.3 ±11.1 hours for HES and NaCl, respectively. Total quantity of study drug infused over four consecutive days, ICU and hospital LOS, and area under the curve of SOFA score were comparable. Acute renal failure occurred in 24 (24.5%) and 19 (20%) patients for HES and NaCl, respectively (P = 0.454). There was no difference between AKIN and RIFLE criteria among groups and no difference in mortality, coagulation, or pruritus up to 90 days after treatment initiation.

Conclusion

Significantly less volume was required to achieve HDS for HES vs. NaCl in the initial phase of fluid resuscitation in severe sepsis patients without any difference for adverse events in both groups.

ClinicalTrials.gov

NCT00464204

Donor heparinization is not a contraindication to liver transplantation even in recipients with acute heparin-induced thrombocytopenia type II: a case report and review of the literature

Heparin-induced thrombocytopenia (HIT) type II is caused by an immune-mediated side effect of heparin anticoagulation resulting in a clotting disorder. In the setting of urgent liver transplantation, the question arises whether a graft from a heparinized donor can be safely transplantated in a recipient with even acute heparin-induced thrombocytopenia type II. We report on a patient with end-stage liver disease and acute HIT II waiting for liver transplantation. Despite the risk of life-threatening complications, an organ procured from a heparinized donor was accepted. Assuming heparin residuals within the graft, the donor organ was flushed backtable with increased amounts of Wisconsin solution. The subsequent transplantation and the postoperative course were uneventful; neither thromboses nor graft dysfunction occurred. Even in acute episode of HIT II with circulating antibodies, a patient may receive an organ from a heparin-treated donor, if adequate precautions during organ preparation are observed.

Cytomegalovirus reactivation and associated outcome of critically ill patients with severe sepsis

INTRODUCTION

Sepsis has been identified as a risk factor for human cytomegalovirus (CMV) reactivation in critically ill patients. However, the contribution of CMV reactivation on morbidity and mortality is still controversial. Therefore, we analyzed the incidence and impact of CMV reactivation on outcome in patients with severe sepsis.

METHODS

In a prospective longitudinal double-blinded observational study, 97 adult nonimmunosuppressed CMV-seropositive patients with new onset of severe sepsis were included. Leukocytes, plasma and tracheal secretions were examined weekly for CMV-DNA by PCR. Tracheal secretions were additionally tested for HSV (Herpes Simplex Virus)-DNA. The influence of CMV-reactivation on the endpoints was analysed by Cox proportional-hazard regression analysis. Time-dependency was evaluated by landmark analysis.

RESULTS

Six out 97 died and five were discharged from the hospital within 72 hours and were excluded of the analysis. CMV reactivation occurred in 35 of the 86 (40.69%) analysed patients. HSV infection occurred in 23 of the 35 (65.7%) CMV reactivators. In 10 patients CMV-plasma-DNAemia appeared with a DNA-content below 600 copies/ml in four cases and a peak amount of 2,830 copies/ml on average. In patients with and without CMV reactivation mortality rates were similar (37.1% vs. 35.3%, P = 0.861), respectively. However, in the multivariate COX regression analyses CMV reactivation was independently associated with increased length of stay in the ICU (30.0, interquartile range 14 to 48 vs. 12.0, interquartile range 7 to 19 days; HR (hazard ratio) 3.365; 95% CI (confidence interval) 1.233 to 9.183, P = 0.018) and in the hospital (33.0, interquartile range 24 to 62 vs. 16.0, interquartile range 10 to 24 days, HR 3.3, 95% CI 1.78 to 6.25, P < 0.001) as well as prolonged mechanical ventilation (22.0, interquartile range 6 to 36 vs. 7.5, interquartile range 5 to 15.5 days; HR 2.6,CI 95% 1.39 to 4.94; P < 0.001) and impaired pulmonary gas exchange (six days, interquartile range 1 to 17, vs. three, interquartile range 1 to 7, days in reactivators vs. non-reactivators, P = 0.038). HSV reactivation proved not to be a risk factor for these adverse effects.

CONCLUSIONS

These data indicate an independent correlation between CMV reactivation and increased morbidity in the well-defined group of nonimmunosuppressed patients with severe sepsis, but CMV reactivation had no impact on mortality in this group with low CMV-DNA plasma levels. Thus, the potential harms and benefits of antiviral treatment have to be weighed cautiously in patients with severe sepsis or septic shock.

Validation criteria for nucleic acid amplification techniques for bacterial infections

Nucleic acid techniques (NATs), such as species-specific and universal polymerase chain reactions (PCRs), are finding ever wider use in the diagnosis of bacterial infection. However, although universal PCR assays, in particular, approach a type of modern Petri dish, they have a number of limitations which restrict their applicability. The sensitivity of universal PCR is lower than that of many species-specific PCRs, and the contamination of samples and PCR reagents with irrelevant DNA from various sources remains a problem. Thus, NATs in general and universal PCR assays in particular require careful validation to be of value for the diagnosis of infection. Validation includes sampling, DNA extraction/isolation, template amplification and visualisation of the results. Furthermore, it implies the establishment of measures of asepsis, the inclusion of positive and negative controls, techniques to optimise the release of DNA from bacterial cells, adequate repetition of the amplification reaction, and routine testing of reagent negative and inhibition controls. Finally, it entails the comparison of results obtained by NATs with those obtained by conventional microbiological methods and matching with clinical evidence of infection. Validation of NATs in clinical diagnosis remains an ongoing challenge. Because of these limitations, NATs can only serve as adjunct tools for the diagnosis of infection in selected cases; they cannot replace conventional culturing techniques.

Emergence of increasing linezolid-resistance in enterococci in a post-outbreak situation with vancomycin-resistant Enterococcus faecium

During 2004 and at the start of 2005 a university hospital in Southwest Germany was affected by an extensive outbreak of vancomycin-resistant Enterococcus faecium (VRE). Although the outbreak was contained, linezolid-resistant enterococci emerged during and after the outbreak as the usage of linezolid became more common. Linezolid resistance was no longer limited to VRE. Nosocomial spread of linezolid-resistant but vancomycin-susceptible E. faecium was detected and these strains also emerged in patients without prior drug exposure. Linezolid should therefore be used with caution and the susceptibility of isolates monitored over time. Isolation precautions and screening of contacts should be considered to avoid spread of resistant isolates.

Antifungal use in intensive care units

OBJECTIVES

To provide benchmarking data on antifungal use in intensive care units (ICUs), to analyse risk factors and to look for correlations with antibiotic use data and structure parameters.

METHODS

Antimicrobial use data for 13 ICUs were obtained from computerized databases from January 2004 through June 2005. Antimicrobial usage density (AD) is expressed as daily defined doses/1000 patient-days. Correlations were calculated by the Spearman correlation or for binomic variables by the two-sided Wilcoxon test. A multivariate regression analysis was performed to identify independent risk factors for the outcome 'antifungal use'.

RESULTS

Mean systemic antifungal drug use was 93.0, the range being between ADs of 18.9 and 232.2. ICUs treating transplant patients had a significantly higher mean antifungal usage at 152.9 compared with ICUs not treating transplant patients where the AD was 46.0. Fluconazole was the most frequently prescribed antifungal (mean AD 69.6) followed by amphotericin B (11.4) and voriconazole (6.2). Antifungal use correlated significantly with the consumption of quinolones, carbapenems and extended-spectrum penicillins, but not with total antibiotic use and not with the type of ICU or university status. In the multivariate linear regression analysis, two parameters, i.e. high quinolone use (P = 0.002) and ICUs which treat transplant patients (P = 0.027), were independent risk factors for a high level of antifungal use.

CONCLUSIONS

Antifungal use was heterogeneous in German ICUs with the mean AD lying at 93. Benchmarking data might provide a useful method for assessing strategies that aim to reduce antifungal use in ICUs. However, data should be stratified for ICUs with and without transplant patients.

[Ventilator-associated pneumonia and multiresistant bacteria]

Ventilator-associated pneumonia remains the most serious nosocomial infection in critically ill patients. Providing appropriate antibiotic therapy promptly is crucial for successful treatment; whereas the diagnostic approach seems to play a minor role. The empirical antibiotic therapy should be guided by the risk for infections due to multiresistant bacteria. For patients at risk a combination therapy, considering local resistance data and formerly applied antibiotic substances, is recommended. Reevaluation and deescalation of antibiotic therapy based on microbiological culture results and discontinuation of antimicrobial treatment after one week is essential for the control of broadspectrum antibiotic use and antibiotic resistance.

Effects of long-term routine use of selective digestive decontamination on antimicrobial resistance

OBJECTIVE

To assess the distribution of bacterial species and antimicrobial resistance in an ICU during long-term use of selective digestive decontamination (SDD) in the context of national reference data.

DESIGN AND SETTING

Five-year prospective observational study in a 24-bed interdisciplinary surgical ICU of a university hospital (study ICU) participating in the project "Surveillance of Antimicrobial Use and Antimicrobial Resistance in German Intensive Care Units" (SARI; reference ICUs).

PATIENTS

Resistance data were obtained from all patients; patients intubated for at least 2 days received SDD (colistin, tobramycin, amphotericin B).

INTERVENTIONS AND MEASUREMENTS

SDD was performed in 1,913 of 7,270 patients. Antimicrobial resistance was examined in 4,597 (study ICU) and 46,346 (reference ICUs) isolates.

RESULTS

Methicillin-resistant Staphylococcus aureus (MRSA) remained stable (2.76 and 2.58 isolates/1000 patient days) in the study ICU; this was below the German average (4.26 isolates/1000 patient days). Aminoglycoside- and betalactam-resistant Gram-negative rods did not increase during SDD use. Aminoglycoside resistance of Pseudomonas aeruginosa was 50% below the mean value of SARI (0.24 vs. 0.52 isolates/1,000 patient days). The relative frequency of enterococci and coagulase-negative staphylococci (CNS) was higher than in the SARI ICUs (23.2% vs. 17.3%, and 25.0% vs. 20.6%, respectively).

CONCLUSION

Routine 5-year-use of SDD was not associated with increased antimicrobial resistance in our ICU with low baseline resistance rates. Vigorous surveillance and control measures to search and destroy MRSA were considered a mandatory component of the SDD program. The relative increase in enterococci and CNS is of concern requiring further investigation.

Hemodynamic evaluation during balloon test occlusion of the sigmoid sinus: clinical and technical considerations

Test occlusion of a patent dural sinus requires careful hemodynamic evaluation. We performed balloon test occlusion of the sigmoid sinus in a patient with an advanced-stage temporal bone malignancy that affected the dominant sigmoid sinus. Before and during the test occlusion, intrasinus pressure was monitored upstream from the balloon via the inner lumen of a double-lumen angioplasty balloon microcatheter. On the basis of the hemodynamic findings, permanent balloon occlusion was carried out without complications.

Effect of comprehensive validation of the template isolation procedure on the reliability of bacteraemia detection by a 16S rRNA gene PCR

The influence of the DNA extraction method on the sensitivity and specificity of bacteraemia detection by a 16S rRNA gene PCR assay was investigated. The detection limit of the assay was 5 fg with purified DNA from Escherichia coli or Staphylococcus aureus, corresponding to one bacterial cell. However, with spiked blood samples, the detection limits were 10(4) and 10(6) CFU/mL, respectively. The sensitivity of the S. aureus assay was improved to the level of the E. coli test with the addition of proteinase K to the commercial DNA extraction kit protocol. Ten (16.6%) of 60 amplification reactions were positive with templates isolated from sterile blood, while PCR reagent controls were negative, thereby indicating contamination during the DNA extraction process. Blood samples were spiked with serial dilutions of E. coli and S. aureus cells, and six PCR results were obtained from three extractions for each blood sample. A classification threshold system was devised, based on the number of positive reactions for each sample. Samples were deemed positive if at least four positive reactions were recorded, making it possible to avoid false-positive results caused by contamination. These results indicate that a comprehensive validation procedure covering all aspects of the assay, including DNA extraction, can improve considerably the validity of PCR assays for bacteraemia, and is a prerequisite for the meaningful detection of bacteraemia by PCR in the clinical setting.