Development of a SARS-CoV-2 Total Antibody Assay and the Dynamics of Antibody Response over Time in Hospitalized and Nonhospitalized Patients with COVID-19.

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2 infections often cause only mild disease that may evoke relatively low Ab titers compared with patients admitted to hospitals. Generally, total Ab bridging assays combine good sensitivity with high specificity. Therefore, we developed sensitive total Ab bridging assays for detection of SARS-CoV-2 Abs to the receptor-binding domain (RBD) and nucleocapsid protein in addition to conventional isotype-specific assays. Ab kinetics was assessed in PCR-confirmed, hospitalized coronavirus disease 2019 (COVID-19) patients (n = 41) and three populations of patients with COVID-19 symptoms not requiring hospital admission: PCR-confirmed convalescent plasmapheresis donors (n = 182), PCR-confirmed hospital care workers (n = 47), and a group of longitudinally sampled symptomatic individuals highly suspect of COVID-19 (n = 14). In nonhospitalized patients, the Ab response to RBD is weaker but follows similar kinetics, as has been observed in hospitalized patients. Across populations, the RBD bridging assay identified most patients correctly as seropositive. In 11/14 of the COVID-19-suspect cases, seroconversion in the RBD bridging assay could be demonstrated before day 12; nucleocapsid protein Abs emerged less consistently. Furthermore, we demonstrated the feasibility of finger-prick sampling for Ab detection against SARS-CoV-2 using these assays. In conclusion, the developed bridging assays reliably detect SARS-CoV-2 Abs in hospitalized and nonhospitalized patients and are therefore well suited to conduct seroprevalence studies.

Culturing periprosthetic tissue in blood culture bottles results in isolation of additional microorganisms.

Despite low sensitivity, culture of periprosthetic tissue (PPT) specimens on agars and in broths has traditionally been used for the detection of causative microorganisms in patients suspected for prosthetic joint infection (PJI). The aim of this study was to evaluate the added diagnostic value of culturing PPT in blood culture bottles (BCB) over the conventional combination of standard agar and broth alone. This prospective cohort study was conducted over a 12-month period and included consecutive patients undergoing revision arthroplasty. Overall, 113 episodes from 90 subjects were studied; 45 subjects (50.0%) met the Infectious Diseases Society of America (IDSA) criteria for PJI, of whom the majority (75.6%) had an acute infection. Sensitivity and specificity of culture were assessed using IDSA criteria for PJI as gold standard. Although the increase in sensitivity from 84.44 (CI 70.54; 93.51) to 93.33% (81.73; 98.60) was not significant, added diagnostic value of culturing PPT in BCBs was demonstrated by the significantly higher number of detected pathogens in culture sets with BCBs compared to culture without BCBs (61 pathogens in conventional set versus 89 when BCBs were included for 57 PJI episodes, P = <0.0001). In 17 (29.8%) episodes, microorganisms were cultured from BCBs only, and in 9 (52.9%) of these episodes, virulent pathogens were found. This study demonstrates that PPT culture in BCBs leads to isolation of additional microorganisms, both virulent and low-virulent, which were not cultured with use of agars and broths alone. Isolation of additional causative microorganisms has serious consequences for the treatment strategy in PJI.

The role of systemic antibiotics in acquiring respiratory tract colonization with gram-negative bacteria in intensive care patients: a nested cohort study.

OBJECTIVE: Colonization of the respiratory tract with Gram-negative bacteria in intensive care patients increases the risk of subsequent infections. Application of systemic antibiotics may prevent colonization with Gram-negative bacteria, but this effect has never been quantified. The objective of this study was to determine associations between systemic antibiotic use and acquisition of respiratory tract colonization with Gram-negative bacteria in ICUs. DESIGN: A nested cohort study. SETTING: A university hospital and a teaching hospital. PATIENTS: Patients with ICU stay of more than 48 hours and absence of respiratory tract colonization with Gram-negative bacteria on ICU admission. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Acquisition was determined through protocolized surveillance. Associations were investigated with Cox regression models with antibiotics as a time-dependent covariate. In all, 250 of 481 patients (52%) acquired respiratory tract colonization with Gram-negative bacteria after a median of 5 days (interquartile range, 3-8 d) (acquisition rate, 77.1/1,000 patient-days at risk). Antibiotic exposure during ICU admission was present in 78% and 72% of the patients with and without acquired Gram-negative bacteria colonization, respectively. In Kaplan-Meier curve analysis, the median times to acquisition of Gram-negative bacteria were 9 days (95% CI, 7.9-10.1) and 6 days (95% CI, 4.8-7.2) in patients receiving and not receiving antibiotics, respectively. In time varying Cox regression analysis, however, the association between acquired colonization and systemic antibiotics was not statistically significant (hazard ratio, 0.90; 95% CI, 0.70-1.16). CONCLUSIONS: Among patients not colonized with Gram-negative bacteria in the respiratory tract at admission to ICU, systemic antibiotics during ICU stay were not associated with a reduction in acquisition of Gram-negative bacteria carriage in the respiratory tract during the ICU stay.

Report of two in situ reconstructions with a saphenous spiral vein graft of Coxiella burnetii-infected aneurysms of the abdominal aorta.

Coxiella burnetii is a rare cause of vascular infections. Yet, Q fever is endemic in the southern part of The Netherlands. This report describes two patients--from the southern part of The Netherlands--with infected aneurysms of the abdominal aorta caused by Coxiella burnetii. Both patients underwent surgical debridement, in situ reconstruction with a great saphenous vein spiral graft, and a transmesenteric omentumplasty. One patient fully recovered, while the other died due to ischemic complications. A multidisciplinary work-up approach to treat infected abdominal aneurysms is proposed, including adequate surgical treatment and long-term antibiotic administration.

A pseudo-outbreak of MRSA due to laboratory contamination related to MRSA carriage of a laboratory staff member.

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is a major burden for hospitals globally. However, in the Netherlands, the MRSA prevalence is relatively low due to the 'search and destroy' policy. Routine multiple-locus variable-number of tandem repeat analysis (MLVA) of MRSA isolates supports outbreak detection. However, whole genome multiple locus sequence typing (wgMLST) is superior to MLVA in identifying (pseudo-)outbreaks with MRSA. The present study describes a pseudo-outbreak of MRSA at the bacteriology laboratory of a large Dutch teaching hospital. METHODS: All staff members of the bacteriology laboratory of the Elisabeth-TweeSteden hospital were screened for MRSA carriage, after a laboratory contamination with MRSA was suspected. Clonal relatedness between the index isolate and the MRSA isolates from laboratory staff members and all previous MRSA isolates from the Elisabeth-TweeSteden hospital with the same MLVA-type as the index case was examined based on wgMLST using whole genome sequencing. RESULTS: One of the staff members was identified as the probable source of the laboratory contamination, because of carriage of a MRSA possessing the same MLVA-type as the index case. Eleven other isolates with the same molecular characteristics were found in the database, of which seven were retrospectively suspected of contamination. Clonal relatedness was found between ten isolates, including the isolate found in the staff member and the MRSA found in the index patient with a maximum of eleven alleles difference. All isolates were epidemiologically linked through the laboratory staff member, who had worked on all these cultures. CONCLUSIONS: The present study describes a MRSA pseudo-outbreak over a 2.5-year period due to laboratory contamination caused by a MRSA carrying laboratory staff member involving nine patients. In case of unexpected bacteriological findings, the possibility of a laboratory contamination should be considered.

Diagnostic value of respiratory virus detection in symptomatic children using real-time PCR.

BACKGROUND: Acute respiratory tract infections are an important public health problem. Sensitive and rapid diagnostic techniques have been developed and are used in daily clinical practice. Here we evaluate the clinical relevance of detecting 20 common respiratory pathogens by molecular methods in a general pediatric clinic. METHODS: Nasopharynx samples of children < 18 years of age with respiratory symptoms referred to a general pediatric clinic were tested for the presence of 19 viruses and Mycoplasma pneumoniae, using real-time polymerase chain reaction. RESULTS: Of 177 patients included in this retrospective study, 73% were positive for at least one virus. Respiratory syncytial virus (36.6%) and human rhinovirus (24%) were most frequently detected. Patients in whom a respiratory virus or Mycoplasma pneumoniae was detected, were younger (6 versus 24 months; p < 0.001) and more often hospitalized (116 versus 34; p = 0.001) than patients in whom no respiratory pathogen was detected. Also they were more likely to present with feeding problems, dyspnea, rhinorrhea and wheezing (all p < 0.05) than patients without a respiratory pathogen.In the majority of cases, clinicians did not change their antibiotic management after detecting a viral respiratory pathogen. No difference in mean Ct value was found between patients with one respiratory pathogen and those with >1 respiratory pathogen (30.5 versus 31.2; p = 0.573). CONCLUSION: Routine testing of common respiratory pathogens could lead to a better understanding of their role in disease in children with respiratory symptoms.

Effect of open and closed endotracheal suctioning on cross-transmission with Gram-negative bacteria: a prospective crossover study.

OBJECTIVE: Cross-transmission of Gram-negative bacteria increases the likelihood of acquisition of infections and emergence of antibiotic resistance in intensive care units. Respiratory tracts of mechanically ventilated patients are frequently colonized with Gram-negative bacteria and endotracheal suctioning may facilitate cross-transmission. It is unknown whether closed suction systems, as compared with open suction systems, prevent cross-transmission. The objective was to determine whether closed suction systems, as compared with open suction systems, reduce the incidence of cross-transmission of Gram-negative bacteria in intensive care units. DESIGN: We performed a prospective crossover study in which both systems were tested unitwide in four intensive care units. SETTING: Two intensive care units from a university hospital and two from a teaching hospital participated in the trial between January 2007 and February 2008. PATIENTS: All patients admitted to the intensive care unit for >24 hrs were included. INTERVENTION: Closed suction systems and open suction systems were used for all patients requiring mechanical ventilation during 6-month clusters with the order of systems randomized per intensive care unit. MEASUREMENTS AND MAIN RESULTS: Acquisition and cross-transmission rates of selected Gram-negative bacteria were determined through extensive microbiological surveillance and genotyping. Among 1,110 patients (585 with closed suction systems and 525 with open suction systems), acquisition for selected Gram-negative bacteria was 35.5 and 32.5 per 1,000 patient-days at risk during closed suction period and open suction period, respectively (adjusted hazard ratio, 1.14; 95% confidence interval, 0.9-1.4). During closed suction period, adjusted hazard ratios for acquisition were 0.66 (95% confidence interval, 0.45-0.97) for Pseudomonas aeruginosa and 2.03 (95% confidence interval, 1.15-3.57) for Acinetobacter species; acquisition rates of other pathogens did not differ significantly. Adjusted hazard ratios for cross-transmission during closed suction period 0.9 (0.4-1.9) for P. aeruginosa, 6.7 (1.5-30.1) for Acinetobacter, and 0.3 (0.03-2.7) for Enterobacter species. Overall cross-transmission rates were 5.9 (closed suction systems) and 4.7 (open suction systems) per 1,000 patient-days at risk. CONCLUSION: Closed suction systems failed to reduce cross-transmission and acquisition rates of the most relevant Gram-negative bacteria in intensive care unit patients.

Antibiotic exposure and resistance development in Pseudomonas aeruginosa and Enterobacter species in intensive care units.

OBJECTIVES: We quantified the association between antibiotic exposure and acquisition of antibiotic resistance in Pseudomonas aeruginosa and Enterobacter species in intensive care unit patients. DESIGN: Prospective cohort study. SETTING AND PATIENTS: In 1,201 patients, respiratory tract colonization was determined through regular screening on admission, twice weekly, and on discharge. Primary outcome was the acquisition of antibiotic resistance in previous antibiotic sensitive P. aeruginosa and Enterobacter species, with acquisition attributable to cross-transmission excluded based on genotyping and epidemiologic linkage. Cox regression analysis, adjusted for covariates, was performed to calculate hazard ratios of patients exposed to antibiotics compared to patients not exposed to antibiotics. MEASUREMENTS AND MAIN RESULTS: In total, 194 and 171 patients were colonized with P. aeruginosa and Enterobacter species, respectively. Two or more cultures per episode were available for 126 and 108 patients. For P. aeruginosa, ceftazidime exposure was associated with 6.3 acquired antibiotic resistance events per 100 days of exposure, whereas incidence rates were lower for ciprofloxacin, meropenem, and piperacillin-tazobactam. In multivariate analysis, meropenem, ciprofloxacin, and ceftazidime were significantly associated with risk of resistance development in P. aeruginosa (adjusted hazard ratio, 11.1; 95% confidence interval, 2.4-51.5 for meropenem; adjusted hazard ratio, 4.1; 95% confidence interval, 1.1-16.2 for ciprofloxacin; adjusted hazard ratio, 2.5; 95% confidence interval, 1.1-5.5 for ceftazidime). For Enterobacter, ceftriaxone and ciprofloxacin exposure were associated with most antibiotic resistance acquisitions. No significant associations were found in multivariate analysis. CONCLUSIONS: Meropenem exposure is associated with the highest risk of resistance development in P. aeruginosa. Increasing carbapenem use attributable to emergence of Gram-negative bacteria producing extended-spectrum ß-lactamases will enhance antibiotic resistance in P. aeruginosa.

Within-patient plasmid dynamics in Klebsiella pneumoniae during an outbreak of a carbapenemase-producing Klebsiella pneumoniae.

INTRODUCTION: Knowledge of within-patient dynamics of resistance plasmids during outbreaks is important for understanding the persistence and transmission of plasmid-mediated antimicrobial resistance. During an outbreak of a Klebsiella pneumoniae carbapenemase-producing (KPC) K. pneumoniae, the plasmid and chromosomal dynamics of K. pneumoniae within-patients were investigated. METHODS: During the outbreak, all K. pneumoniae isolates of colonized or infected patients were collected, regardless of their susceptibility pattern. A selection of isolates was short-read and long-read sequenced. A hybrid assembly of the short-and long-read sequence data was performed. Plasmid contigs were extracted from the hybrid assembly, annotated, and within patient plasmid comparisons were performed. RESULTS: Fifteen K. pneumoniae isolates of six patients were short-read whole-genome sequenced. Whole-genome multi-locus sequence typing revealed a maximum of 4 allele differences between the sequenced isolates. Within patients 1 and 2 the resistance gene- and plasmid replicon-content did differ between the isolates sequenced. Long-read sequencing and hybrid assembly of 4 isolates revealed loss of the entire KPC-gene containing plasmid in the isolates of patient 2 and a recombination event between the plasmids in the isolates of patient 1. This resulted in two different KPC-gene containing plasmids being simultaneously present during the outbreak. CONCLUSION: During a hospital outbreak of a KPC-producing K. pneumoniae isolate, plasmid loss of the KPC-gene carrying plasmid and plasmid recombination was detected within the isolates from two patients. When investigating outbreaks, one should be aware that plasmid transmission can occur and the possibility of within- and between-patient plasmid variation needs to be considered.

[COVID-19: patient zero in the Netherlands]. / COVID-19: patiënt nul in Nederland.

BACKGROUND: Since December 2019, the world is captivated by SARS-CoV-2, a new coronavirus that shows a lot of similaritieswith previous coronaviruses such as SARS and MERS. Although it was initially seen mainly in China and the surrounding countries, now it also reached Europe, where a large region in northern Italy, in particular, encountered many infections. CASE DESCRIPTION: Here we describe the first Dutch patient with COVID-19, a 56-year-old man whose infection appeared to be related to a trip to Northern Italy one week before presentation. In the days that followed, the brother of the patient with whom he had traveled, his wife and daughter also tested positive. CONCLUSION: At the moment much is still unclear and it is particularly important to quickly identify patients with an increased risk of complications and to prevent unrestrained spread in the Netherlands.

Prevalence and Clinical Presentation of Health Care Workers With Symptoms of Coronavirus Disease 2019 in 2 Dutch Hospitals During an Early Phase of the Pandemic.

Importance: On February 27, 2020, the first patient with coronavirus disease 2019 (COVID-19) was reported in the Netherlands. During the following weeks, at 2 Dutch teaching hospitals, 9 health care workers (HCWs) received a diagnosis of COVID-19, 8 of whom had no history of travel to China or northern Italy, raising the question of whether undetected community circulation was occurring. Objective: To determine the prevalence and clinical presentation of COVID-19 among HCWs with self-reported fever or respiratory symptoms. Design, Setting, and Participants: This cross-sectional study was performed in 2 teaching hospitals in the southern part of the Netherlands in March 2020, during the early phase of the COVID-19 pandemic. Health care workers employed in the participating hospitals who experienced fever or respiratory symptoms were asked to voluntarily participate in a screening for infection with the severe acute respiratory syndrome coronavirus 2. Data analysis was performed in March 2020. Main Outcomes and Measures: The prevalence of severe acute respiratory syndrome coronavirus 2 infection was determined by semiquantitative real-time reverse transcriptase-polymerase chain reaction on oropharyngeal samples. Structured interviews were conducted to document symptoms for all HCWs with confirmed COVID-19. Results: Of 9705 HCWs employed (1722 male [18%]), 1353 (14%) reported fever or respiratory symptoms and were tested. Of those, 86 HCWs (6%) were infected with severe acute respiratory syndrome coronavirus 2 (median age, 49 years [range, 22-66 years]; 15 [17%] male), representing 1% of all HCWs employed. Most HCWs experienced mild disease, and only 46 (53%) reported fever. Eighty HCWs (93%) met a case definition of fever and/or coughing and/or shortness of breath. Only 3 (3%) of the HCWs identified through the screening had a history of travel to China or northern Italy, and 3 (3%) reported having been exposed to an inpatient with a known diagnosis of COVID-19 before the onset of symptoms. Conclusions and Relevance: Within 2 weeks after the first Dutch case was detected, a substantial proportion of HCWs with self-reported fever or respiratory symptoms were infected with severe acute respiratory syndrome coronavirus 2, likely as a result of acquisition of the virus in the community during the early phase of local spread. The high prevalence of mild clinical presentations, frequently not including fever, suggests that the currently recommended case definition for suspected COVID-19 should be used less stringently.

The burden of bacteremic and non-bacteremic Gram-negative infections: A prospective multicenter cohort study in a low-resistance country.

Objectives There is a global increase in infections caused by Gram-negative bacteria. The majority of research is on bacteremic Gram-negative infections (GNI), leaving a knowledge gap on the burden of non-bacteremic GNI. Our aim is to describe characteristics and determine the burden of bacteremic and non-bacteremic GNI in hospitalized patients in the Netherlands. Methods We conducted a prospective cohort study of patients in eight hospitals with microbiologically confirmed GNI, between June 2013 and November 2015. In each hospital the first five adults meeting the eligibility criteria per week were enrolled. We estimated the national incidence and mortality of GNI by combining the cohort data with a national surveillance database for antimicrobial resistance. Results 1,954 patients with GNI were included of which 758 (39%) were bloodstream infections (BSI). 243 GNI (12%) involved multi-drug resistant pathogens. 30-day mortality rate was 11.1% (n = 217) Estimated national incidences of non-bacteremic GNI and bacteremic GNI in hospitalized adults were 74 (95% CI 58 - 89) and 86 (95% CI 72-100) per 100,000 person years, yielding estimated annual numbers of 30-day all-cause mortality deaths of 1,528 (95% CI 1,102-1,954) for bacteremic and 982 (95% CI 688 - 1,276) for non-bacteremic GNI. Conclusion GNI form a large mortality burden in a low-resistance country. A third of the associated mortality occurs after non-bacteremic GNI.

Attributable mortality of antibiotic resistance in gram-negative infections in the Netherlands: a parallel matched cohort study.

OBJECTIVES: Antibiotic resistance in Gram-negative bacteria has been associated with increased mortality. This was demonstrated mostly for third-generation cephalosporin-resistant (3GC-R) Enterobacterales bacteraemia in international studies. Yet, the burden of resistance specifically in the Netherlands and created by all types of Gram-negative infection has not been quantified. We therefore investigated the attributable mortality of antibiotic resistance in Gram-negative infections in the Netherlands. METHODS: In eight hospitals, a sample of Gram-negative infections was identified between 2013 and 2016, and separated into resistant and susceptible infection cohorts. Both cohorts were matched 1:1 to non-infected control patients on hospital, length of stay at infection onset, and age. In this parallel matched cohort set-up, 30-day mortality was compared between infected and non-infected patients. The impact of resistance was then assessed by dividing the two separate risk ratios (RRs) for mortality attributable to Gram-negative infection. RESULTS: We identified 1954 Gram-negative infections, of which 1190 (61%) involved Escherichia coli, 210 (11%) Pseudomonas aeruginosa, and 758 (39%) bacteraemia. Resistant Gram-negatives caused 243 infections (12%; 189 (78%) 3GC-R Enterobacterales, nine (4%) multidrug-resistant P. aeruginosa, no carbapenemase-producing Enterobacterales). Subsequently, we matched 1941 non-infected controls. After adjustment, point estimates for RRs comparing mortality between infections and controls were similarly higher than 1 in case of resistant infections and susceptible infections (1.42 (95% confidence interval 0.66-3.09) and 1.32 (1.06-1.65), respectively). By dividing these, the RR reflecting attributable mortality of resistance was calculated as 1.08 (0.48-2.41). CONCLUSIONS: In the Netherlands, antibiotic resistance did not increase 30-day mortality in Gram-negative infections.

COVID-19 in health-care workers in three hospitals in the south of the Netherlands: a cross-sectional study.

BACKGROUND: 10 days after the first reported case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the Netherlands (on Feb 27, 2020), 55 (4%) of 1497 health-care workers in nine hospitals located in the south of the Netherlands had tested positive for SARS-CoV-2 RNA. We aimed to gain insight in possible sources of infection in health-care workers. METHODS: We did a cross-sectional study at three of the nine hospitals located in the south of the Netherlands. We screened health-care workers at the participating hospitals for SARS-CoV-2 infection, based on clinical symptoms (fever or mild respiratory symptoms) in the 10 days before screening. We obtained epidemiological data through structured interviews with health-care workers and combined this information with data from whole-genome sequencing of SARS-CoV-2 in clinical samples taken from health-care workers and patients. We did an in-depth analysis of sources and modes of transmission of SARS-CoV-2 in health-care workers and patients. FINDINGS: Between March 2 and March 12, 2020, 1796 (15%) of 12 022 health-care workers were screened, of whom 96 (5%) tested positive for SARS-CoV-2. We obtained complete and near-complete genome sequences from 50 health-care workers and ten patients. Most sequences were grouped in three clusters, with two clusters showing local circulation within the region. The noted patterns were consistent with multiple introductions into the hospitals through community-acquired infections and local amplification in the community. INTERPRETATION: Although direct transmission in the hospitals cannot be ruled out, our data do not support widespread nosocomial transmission as the source of infection in patients or health-care workers. FUNDING: EU Horizon 2020 (RECoVer, VEO, and the European Joint Programme One Health METASTAVA), and the National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Contact precautions in single-bed or multiple-bed rooms for patients with extended-spectrum ß-lactamase-producing Enterobacteriaceae in Dutch hospitals: a cluster-randomised, crossover, non-inferiority study.

BACKGROUND: Use of single-bed rooms for control of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae is under debate; the added value when applying contact precautions has not been shown. We aimed to assess whether an isolation strategy of contact precautions in a multiple-bed room was non-inferior to a strategy of contact precautions in a single-bed room for preventing transmission of ESBL-producing Enterobacteriaceae. METHODS: We did a cluster-randomised, crossover, non-inferiority study on medical and surgical wards of 16 Dutch hospitals. During two consecutive study periods, either contact precautions in a single-bed room or contact precautions in a multiple-bed room were applied as the preferred isolation strategy for patients with ESBL-producing Enterobacteriaceae cultured from a routine clinical sample (index patients). Eligible index patients were aged 18 years or older, had no strict indication for barrier precautions in a single-bed room, had a culture result reported within 7 days of culture and before discharge, and had no wardmate known to be colonised or infected with an ESBL-producing Enterobacteriaceae isolate of the same bacterial species with a similar antibiogram. Hospitals were randomly assigned in a 1:1 ratio by computer to one of two sequences of isolation strategies, stratified by university or non-university hospital. Allocation was masked for laboratory technicians who assessed the outcomes but not for patients, treating doctors, and infection-control practitioners enrolling index patients. The primary outcome was transmission of ESBL-producing Enterobacteriaceae to wardmates, which was defined as rectal carriage of an ESBL-producing Enterobacteriaceae isolate that was clonally related to the index patient's isolate in at least one wardmate. The primary analysis was done in the per-protocol population, which included patients who were adherent to the assigned room type. A 10% non-inferiority margin for the risk difference was used to assess non-inferiority. This study is registered with Nederlands Trialregister, NTR2799. FINDINGS: 16 hospitals were randomised, eight to each sequence of isolation strategies. All hospitals randomised to the sequence single-bed room then multiple-bed room and five of eight hospitals randomised to the sequence multiple-bed room then single-bed room completed both study periods and were analysed. From April 24, 2011, to Feb 27, 2014, 1652 index patients and 12 875 wardmates were assessed for eligibility. Of those, 693 index patients and 9527 wardmates were enrolled and 463 index patients and 7093 wardmates were included in the per-protocol population. Transmission of ESBL-producing Enterobacteriaceae to at least one wardmate was identified for 11 (4%) of 275 index patients during the single-bed room strategy period and for 14 (7%) of 188 index patients during the multiple-bed room strategy period (crude risk difference 3·4%, 90% CI -0·3 to 7·1). INTERPRETATION: For patients with ESBL-producing Enterobacteriaceae cultured from a routine clinical sample, an isolation strategy of contact precautions in a multiple-bed room was non-inferior to a strategy of contact precautions in a single-bed room for preventing transmission of ESBL-producing Enterobacteriaceae. Non-inferiority of the multiple-bed room strategy might change the current single-bed room preference for isolation of patients with ESBL-producing Enterobacteriaceae and, thus, broaden infection-control options for ESBL-producing Enterobacteriaceae in daily clinical practice. FUNDING: Netherlands Organisation for Health Research and Development.

Shortening the incubation time for antimicrobial susceptibility testing by disk diffusion for Enterobacteriaceae: how short can it be and are the results accurate?

The standard incubation time for antimicrobial susceptibility testing (AST) by disk diffusion is primarily based on laboratory working hours rather than growth and kill characteristics of bacteria. Faster AST results could result in better patient outcomes and reduced costs by initiating earlier appropriate therapy. The earliest possible reading moment for disk diffusion using established disk zone diameter breakpoints for Enterobacteriaceae was determined with a special focus on the accuracy of the results. A total of 88 Enterobacteriaceae challenge isolates, including isolates with specific resistance mechanisms such as extended-spectrum ß-lactamase (ESBL), were subjected to disk diffusion with 15 antibiotics. Hourly images were automatically produced by an incubator/camera combination from 1 h to 20 h. Disk zones were plotted over time for all combinations. Essential and categorical agreement rates using the final reading after 20 h of incubation as a reference were calculated for every hour. In total, 1320 antibiotic-micro-organism combinations were tested. Clear growth with readable inhibition zones was visible after 6 h of incubation for the majority (95.8%) of plates and after 7 h for all incubated plates. However, zone sizes changed significantly after those time points for a number of strains. After 10 h of incubation, minor, major and very major error rates were 1.6% (n = 21), 0.2% (n = 1) and 0.7% (n = 4), respectively. The results of this study clearly indicate that early reading of inhibition zones to 10 h after incubation is feasible and accurate and thus may save significantly on turnaround time.

Shortening the incubation time for the combination disk diffusion extended-spectrum ß-lactamase (ESBL) confirmation test: how far can we go?

The combination disk diffusion extended-spectrum ß-lactamase (ESBL) confirmation test (CDT) is used for the confirmation of ESBL production in Enterobacteriaceae and usually takes 16-20 h to results. In this study, we searched for the shortest possible incubation time without a reduction in reliability. A total of 125 ESBL screening-positive isolates were subjected to CDT and were molecularly characterised by microarray. Inhibition zones were read every hour over 6-18 h of incubation. Concordance between earlier and 18-h readings was calculated for each hour. Results were validated on 224 isolates during routine clinical practice. For the initial 125 isolates, concordance (Cohen's κ) between the 6-h and 18-h readings was 0.88 [95% confidence interval (CI) 0.78-0.96; P <0.001]. The earliest time point for full concordance with the 18-h reading was 10 h. Validation of the 10-h reading for 224 clinical isolates resulted in a concordance of 0.99 (95% CI 0.98-1.0) between the 10-h and 18-h readings. Overall concordance on all 349 isolates was 0.99 (95% CI 0.97-1.0). Reading after 10 h of incubation has an excellent correlation with results after 18 h of incubation. This can significantly reduce the turnaround time for ESBL detection in laboratories with long opening hours or providing a 24/7 service. Consequently, there is a potential for implementing infection control measures up to 8 h earlier.

[Meningitis after a mouse bite]. / Meningitis na muizenbeet.

BACKGROUND: Infection with the lymphocytic choriomeningitis virus is a human zoonosis caused by a rodent-borne arenavirus and is often seen in autumn and winter when mice retreat into houses. Infection in humans is acquired after inhalation of aerosols or direct contact with excreta of an infected rodent. CASE DESCRIPTION: A 37-year-old woman was referred to St. Elisabeth hospital in Tilburg, Netherlands, complaining of severe progressive headache, nausea and vomiting. Three weeks before presentation a mouse had bitten her finger. On neurological examination there were no abnormalities. Cerebrospinal fluid investigations indicated viral meningitis. Immunofluorescence serological testing confirmed the diagnosis of lymphocytic choriomeningitis. CONCLUSION: Infection by lymphocytic choriomeningitis virus after contact with rodents can cause viral meningitis. The acquired form of the disease is known to be self-limiting in immunocompetent patients.

Viral and bacterial aetiology of community-acquired pneumonia in adults.

BACKGROUND: Modern molecular techniques reveal new information on the role of respiratory viruses in community-acquired pneumonia. In this study, we tried to determine the prevalence of respiratory viruses and bacteria in patients with community-acquired pneumonia who were admitted to the hospital. METHODS: Between April 2008 and April 2009, 408 adult patients (aged between 20 and 94 years) with community-acquired pneumonia were tested for the presence of respiratory pathogens using bacterial cultures, real-time PCR for viruses and bacteria, urinary antigen testing for Legionella and Pneumococci and serology for the presence of viral and bacterial pathogens. RESULTS: Pathogens were identified in 263 (64·5%) of the 408 patients. The most common single organisms in these 263 patients were Streptococcus pneumoniae (22·8%), Coxiella burnetii (6·8%) and influenza A virus (3·8%). Of the 263 patients detected with pathogens, 117 (44·5%) patients were positive for one or more viral pathogens. Of these 117 patients, 52 (44·4%) had no bacterial pathogen. Multiple virus infections (≥2) were found in 16 patients. CONCLUSION: In conclusion, respiratory viruses are frequently found in patients with CAP and may therefore play an important role in the aetiology of this disease.

Recent emergence of Staphylococcus aureus clonal complex 398 in human blood cultures.

BACKGROUND: Recently, a clone of MRSA with clonal complex 398 (CC398) has emerged that is related to an extensive reservoir in animals, especially pigs and veal calves. It has been reported previously that methicillin-susceptible variants of CC398 circulate among humans at low frequency, and these have been isolated in a few cases of bloodstream infections (BSI). The purpose of this study was to determine the prevalence of S. aureus CC398 in blood cultures taken from patients in a geographic area with a high density of pigs. METHODOLOGY/PRINCIPAL FINDINGS: In total, 612 consecutive episodes of S. aureus BSI diagnosed before and during the emergence of CC398 were included. Three strains (2 MSSA and 1 MRSA) that were isolated from bacteremic patients between 2010-2011 were positive in a CC398 specific PCR. There was a marked increase in prevalence of S. aureus CC398 BSI isolated between 2010-2011 compared to the combined collections that were isolated between 1996-1998 and 2002-2005 (3/157, 1.9% vs. 0/455, 0.0%; p = 0.017). CONCLUSIONS/SIGNIFICANCE: In conclusion, in an area with a relative high density of pigs, S. aureus CC398 was found as a cause of BSI in humans only recently. This indicates that S. aureus CC398 is able to cause invasive infections in humans and that the prevalence is rising. Careful monitoring of the evolution and epidemiology of S. aureus CC398 in animals and humans is therefore important.