Do we need to change catheter-related bloodstream infection surveillance in the Netherlands? A qualitative study among infection prevention professionals.

OBJECTIVES: Catheter-related bloodstream infections (CRBSI) are a common healthcare-associated infection and therefore targeted by surveillance programmes in many countries. Concerns, however, have been voiced regarding the reliability and construct validity of CRBSI surveillance and the connection with the current diagnostic procedures. The aim of this study was to explore the experiences of infection control practitioners (ICPs) and medical professionals with the current CRBSI surveillance in the Netherlands and their suggestions for improvement. DESIGN: Qualitative study using focus group discussions (FGDs) with ICPs and medical professionals separately, followed by semistructured interviews to investigate whether the points raised in the FGDs were recognised and confirmed by the interviewees. Analyses were performed using thematic analyses. SETTING: Basic, teaching and academic hospitals in the Netherlands. PARTICIPANTS: 24 ICPs and 9 medical professionals. RESULTS: Main themes derived from experiences with current surveillance were (1) ICPs' doubt regarding the yield of surveillance given the low incidence of CRBSI, the high workload and IT problems; (2) the experienced lack of leadership and responsibility for recording information needed for surveillance and (3) difficulties with applying and interpreting the CRBSI definition. Suggestions were made to simplify the surveillance protocol, expand the follow-up and surveillance to homecare settings, simplify the definition and customise it for specific patient groups. Participants reported hoping for and counting on automatisation solutions to support future surveillance. CONCLUSIONS: This study reveals several problems with the feasibility and acceptance of the current CRBSI surveillance and proposes several suggestions for improvement. This provides valuable input for future surveillance activities, thereby taking into account automation possibilities.

Limited influence of hospital wastewater on the microbiome and resistome of wastewater in a community sewerage system.

Effluents from wastewater treatment plants (WWTPs) have been proposed to act as point sources of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in the environment. Hospital sewage may contribute to the spread of ARB and ARGs as it contains the feces and urine of hospitalized patients, who are more frequently colonized with multi-drug resistant bacteria than the general population. However, whether hospital sewage noticeably contributes to the quantity and diversity of ARGs in the general sewerage system has not yet been determined.Here, we employed culture-independent techniques, namely 16S rRNA gene sequencing and nanolitre-scale quantitative PCRs, to assess the role of hospital effluent as a point source of ARGs in the sewerage system, through comparing microbiota composition and levels of ARGs in hospital sewage with WWTP influent with and without hospital sewage.Compared to other sites, hospital sewage was richest in human-associated bacteria and contained the highest relative levels of ARGs. Yet, the relative abundance of ARGs was comparable in the influent of WWTPs with and without hospital sewage, suggesting that hospitals do not contribute importantly to the quantity and diversity of ARGs in the investigated sewerage system.

Appendiceal spirochaetosis in children.

BACKGROUND: Acute appendicitis is a surgical emergency in which the appendix is surgically removed to prevent peritonitis due to perforation of the appendix. Depending on age and gender, up to 17% of removed appendices do not show the histopathological changes pathognomonic for acute appendicitis and are called 'pseudo-appendicitis'. Intestinal spirochaetes have been reported in up to 12.3% of these non-inflamed appendices obtained from adults. Although children carry the highest risk for acute appendicitis, not much is known on the prevalence of intestinal spirochaetes in children. The aim of this study was to determine whether there is an association between pseudo-appendicitis and appendiceal spirochaetosis in children. METHODS: Archival appendix specimens from paediatric patients (less than 18 years old) were obtained from two Dutch hospitals (acute appendicitis, n = 63; pseudo-appendicitis, n = 55; control appendices, n = 33) and microscopically analysed by H&E staining and spirochaete-specific immunohistochemistry and Brachyspira species specific real-time PCR. RESULTS: Five out of 142 appendices were found to be positive, all in male patients: one in the acute appendicitis group, two in the pseudo-appendicitis group and two in the control group. CONCLUSION: The results obtained do not provide evidence for a role of Brachyspira species infection in the aetiology of acute appendicitis in children.

New methods to analyse microarray data that partially lack a reference signal.

BACKGROUND: Microarray-based Comparative Genomic Hybridisation (CGH) has been used to assess genetic variability between bacterial strains. Crucial for interpretation of microarray data is the availability of a reference to compare signal intensities to reliably determine presence or divergence each DNA fragment. However, the production of a good reference becomes unfeasible when microarrays are based on pan-genomes.When only a single strain is used as a reference for a multistrain array, the accessory gene pool will be partially represented by reference DNA, although these genes represent the genomic repertoire that can explain differences in virulence, pathogenicity or transmissibility between strains. The lack of a reference makes interpretation of the data for these genes difficult and, if the test signal is low, they are often deleted from the analysis. We aimed to develop novel methods to determine the presence or divergence of genes in a Staphylococcus aureus multistrain PCR product microarray-based CGH approach for which reference DNA was not available for some probes. RESULTS: In this study we have developed 6 new methods to predict divergence and presence of all genes spotted on a multistrain Staphylococcus aureus DNA microarray, published previously, including those gene spots that lack reference signals. When considering specificity and PPV (i.e. the false-positive rate) as the most important criteria for evaluating these methods, the method that defined gene presence based on a signal at least twice as high as the background and higher than the reference signal (method 4) had the best test characteristics. For this method specificity was 100% and 82% for MRSA252 (compared to the GACK method) and all spots (compared to sequence data), respectively, and PPV were 100% and 76% for MRSA252 (compared to the GACK method) and all spots (compared to sequence data), respectively. CONCLUSION: A definition of gene presence based on signal at least twice as high as the background and higher than the reference signal (method 4) had the best test characteristics, allowing the analysis of 6-17% more of the genes not present in the reference strain. This method is recommended to analyse microarray data that partially lack a reference signal.