IntroductionSuspected urinary tract infection (UTI) ranks among the most common reasons for antibiotic use in nursing homes. However, diagnosing UTI in this setting is challenging because UTI often presents with non-specific symptomatology. Moreover asymptomatic bacteriuria is common in elderly, which complicates attribution of causality to detection of bacteria in urine. These diagnostic challenges contribute to overuse of antibiotics and emergence of antimicrobial resistance in nursing homes. Given the diagnostic challenges, there is a need for point-of-care (POC) diagnostic tests to support clinical rules for diagnosing UTI. Procalcitonin (PCT) and C reactive protein (CRP) are inflammatory blood markers that have been proven useful to support diagnosis and monitoring of (bacterial) respiratory tract infections and sepsis. While limited studies suggest their usefulness in supporting UTI diagnosis, their utility has not been studied in elderly populations for this purpose.Methods and analysisIn a 24-month matched prospective study, ‘PROGRESS’ will assess and compare the sensitivity of rapid POC measurements of blood CRP and PCT levels to support clinical rules for diagnosing UTI in nursing home residents. The primary outcome measure is sensitivity of the POC tests to identify patients with true UTI based on the predefined definition, as derived from receiver operating curves.Ethics and disseminationThis study will be conducted in accordance with Good Clinical Practice guidelines and the principles of the Declaration of Helsinki. The study protocol is approved by the Medical Ethical Committee of Amsterdam UMC location VUmc with reference number 2017.350 and National Central Committee on Research involving Human Subjects with reference number NL62067.029.17.Trial registration numberNTR6467.

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Background: The importance of protein glycosylation in regulating lipid metabolism is becoming increasingly apparent. We set out to further investigate this by studying patients with type I congenital disorders of glycosylation (CDGs) with defective N-glycosylation. Methods: We studied 29 patients with the 2 most prevalent types of type I CDG, ALG6 (asparagine-linked glycosylation protein 6)–deficiency CDG and PMM2 (phosphomannomutase 2)–deficiency CDG, and 23 first- and second-degree relatives with a heterozygous mutation and measured plasma cholesterol levels. Low-density lipoprotein (LDL) metabolism was studied in 3 cell models—gene silencing in HepG2 cells, patient fibroblasts, and patient hepatocyte-like cells derived from induced pluripotent stem cells—by measuring apolipoprotein B production and secretion, LDL receptor expression and membrane abundance, and LDL particle uptake. Furthermore, SREBP2 (sterol regulatory element-binding protein 2) protein expression and activation and endoplasmic reticulum stress markers were studied. Results: We report hypobetalipoproteinemia (LDL cholesterol [LDL-C] and apolipoprotein B below the fifth percentile) in a large cohort of patients with type I CDG (mean age, 9 years), together with reduced LDL-C and apolipoprotein B in clinically unaffected heterozygous relatives (mean age, 46 years), compared with 2 separate sets of age- and sex-matched control subjects. ALG6 and PMM2 deficiency led to markedly increased LDL uptake as a result of increased cell surface LDL receptor abundance. Mechanistically, this outcome was driven by increased SREBP2 protein expression accompanied by amplified target gene expression, resulting in higher LDL receptor protein levels. Endoplasmic reticulum stress was not found to be a major mediator. Conclusions: Our study establishes N-glycosylation as an important regulator of LDL metabolism. Given that LDL-C was also reduced in a group of clinically unaffected heterozygotes, we propose that increasing LDL receptor–mediated cholesterol clearance by targeting N-glycosylation in the LDL pathway may represent a novel therapeutic strategy to reduce LDL-C and cardiovascular disease.

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Background Diagnosing urinary tract infections (UTI) in nursing home residents is complex, as specific urinary symptoms are often absent and asymptomatic bacteriuria (ASB) is prevalent. The aim of this study was to assess the sensitivity of blood C-reactive protein (CRP) and procalcitonin (PCT) measured by Point-of-Care tests (PoCT) to diagnose UTI in this setting. Methods Elderly residents (≥ 65 years old) with a suspected UTI were recruited from psychogeriatric, somatic, or rehabilitation wards, in the thirteen participating nursing homes. CRP and PCT were tested simultaneously in the same study participants. To assess the sensitivities, a stringent definition of ‘true’ UTI was used including the presence of symptoms, urinary leucocytes, positive urine culture and symptom resolution during antibiotic treatment covering isolated uropathogen(s). The original sample size was 440 suspected UTI episodes, to detect a clinically relevant sensitivity of at least 65%, calculated for the matched analysis approach comparing both PoCT. Results After enrolment of 302 episodes (68.6% of the planned sample size) an unplanned and funder-mandated interim analysis was done, resulting in premature discontinuation of the study for futility. For 247 of 266 eligible episodes all mandatory items required for the ‘true’ UTI definition (92.9%) were available. In total, 49 episodes fulfilled our stringent UTI definition (19.8%). The sensitivities of CRP (cut-off 6.5 mg/L) and PCT (cut-off 0.025 ng/mL) were 52.3% (36.7-67.5%, 95%-CI) and 37.0% (23.2-52.5%, 95%-CI) respectively. Conclusion Our results indicate that CRP and PCT are not suitable to distinguish UTI and ASB in nursing home residents. Trial registration Netherlands Trial Registry NL6293

Background: Bacteria produce volatile organic compounds (VOCs) during growth, which can be detected by colorimetric sensor arrays (CSAs). The SpecifAST® system (Specific Diagnostics) employs this technique to enable antibiotic susceptibility testing (AST) directly from blood cultures without prior subculture of isolates. The aim of this study was to compare the SpecifAST® AST results and analysis time to the VITEK®2 (bioMérieux) system. Methods: In a 12-month single site prospective study, remnants of clinical positive monomicrobial blood cultures were combined with a series of antibiotic concentrations. Volatile emission was monitored at 37 °C via CSAs. Minimal Inhibitory Concentrations (MICs) of seven antimicrobial agents for Enterobacterales, Staphylococcus, and Enterococcus spp. were compared to VITEK®2 AST results. MICs were interpreted according to EUCAST clinical breakpoints. Performance was assessed by calculating agreement and discrepancy rates. Results: In total, 96 positive blood cultures containing Enterobacterales, Staphylococcus, and Enterococcus spp. were tested (269 bug–drug combinations). The categorical agreement of the SpecifAST® system compared to the VITEK®2 system was 100% and 91% for Gram-negatives and Gram-positives, respectively. Errors among Gram-positives were from coagulase-negative staphylococci. Overall results were available in 3.1 h (±0.9 h) after growth detection without the need for subculture steps. Conclusion: The AST results based on VOC detection are promising and warrant further evaluation in studies with a larger sample of bacterial species and antimicrobials.

Background Diagnosing urinary tract infections (UTI) in nursing home residents is complex, due to frequent non-specific symptomatology and asymptomatic bacteriuria. The objective of this study was to explore health care professionals’ perceptions of the proposed use of inflammatory marker Point-Of-Care Testing (POCT) in this respect. Methods We conducted a qualitative inquiry (2018–2019) alongside the multicenter PROGRESS study (NL6293), which assessed the sensitivity of C-reactive protein and procalcitonin POCT in UTI. We used semi-structured face-to-face interviews. The participants were physicians (n = 12) and nurses (n = 6) from 13 nursing homes in the Netherlands. Most respondents were not familiar with inflammatory marker POCT, while some used POCT for respiratory tract infections. Both the interview guide and the analysis of the interview transcripts were based on the Consolidated Framework for Implementation Research. Results All respondents acknowledged that sufficiently sensitive POCT could decrease diagnostic uncertainty to some extent in residents presenting with non-specific symptoms. They primarily thought that negative test results would rule out UTI and justify withholding antibiotic treatment. Secondly, they described how positive test results could rule in UTI and justify antimicrobial treatment. However, most respondents also expected new diagnostic uncertainties to arise. Firstly, in case of negative test results, they were not sure how to deal with residents’ persisting non-specific symptoms. Secondly, in case of positive test results, they feared overlooking infections other than UTI. These new uncertainties could lead to inappropriate antibiotics use. Therefore, POCT was thought to create a false sense of confidence. Conclusions Our study suggests that inflammatory marker POCT will only improve UTI management in nursing homes to some extent. To realize the expected added value, any implementation of POCT requires thorough guidance to ensure appropriate use. Developing UTI markers with high negative and positive predictive values may offer greater potential to improve UTI management in nursing homes.

The appropriate use of microbiological investigations is an important cornerstone of antibiotic stewardship programmes, but receives relatively limited attention. This study aimed to identify influencing factors in performing microbiological diagnostic tests and to assess the need for a clinical guideline. We performed a qualitative (focus group) and quantitative (online questionnaire survey) study among medical specialists and residents to identify physicians’ considerations in performing microbiological diagnostic tests and to assess the need for a diagnostic guideline. The questionnaire consisted of 14 statements, divided into three categories: knowledge, influencing factors and presence of guidelines. The questionnaire was sent to physicians of the departments of internal medicine, intensive care, paediatrics and pulmonology in five hospitals in the Netherlands. Sub-analyses for medical specialists versus residents and for paediatric versus non-paediatric departments were performed. We included 187 completed questionnaires in our analyses. The physicians reported having adequate knowledge on methods, time-to-result and accuracy, but inadequate knowledge on costs of the tests. Patients’ clinical condition, comorbidity, local guidelines and accuracy of tests were appraised as the four most important influencing factors to perform tests. Over 70% (132/187) of physicians reported being interested in a guideline for microbiological diagnostic testing. Fifteen physicians (8.0%) provided additional comments. This study identifies the influencing factors to microbiological testing and shows the demand for a clinical guideline among physicians. Importance Microbiological diagnostic tests are an important cornerstone within antibiotic stewardship programmes [ 1 – 5 ]. These programmes aim to ameliorate the appropriate use of antibiotics and thus improve clinical outcomes of infectious diseases, whilst reducing the emergence of antimicrobial resistance [ 6 ]. However, inappropriate microbiological testing is a widely recognised problem [ 7 – 12 ], and influencing factors to testing have not been studied in the past. Our research shows the demand for a clinical guideline among physicians, and it identifies their influencing factors to testing. These results can be used to create a clinical guideline for microbiological diagnostic testing, thus supporting antibiotic stewardship programmes and reducing antimicrobial resistance.