Introduction/objective With the CoLab score and/or the viability polymerase chain reaction (v-PCR) test, one can determine sooner than currently possible when a COVID-19 patient can be de-isolated. The CoLab score detects host response (blood), v-PCR test intact SARS-CoV-2 particles (nasopharyngeal swab). We investigated a potential implementation of these tests in the ICU. Design/setting Based on interviews in two Dutch hospitals, a FRAM model was built to visualize the process of clinical use of both tests. MIDI questionnaire (implementation), and mini-HTA tool (effects/costs) served as research framework. Results Work processes fit well within the current care (ICU, laboratories, IT). Correct determination of blood parameters and representativeness of the swab are crucial. Optimal interdisciplinary collaboration, knowledge of benefits of timely de-isolation, and validity are relevant for implementation. De-isolation improves ICU workflow and quality of care. Expected gains are fewer days in isolation and cost savings from reduced use of disposable protective material. Healthcare staff welcomes the potential of these tests. However, constantly changing conditions due to virus mutations, emergence of other viruses, (not present at the beginning of the pandemic when the tests were validated), relatively quick changes in patient types and numbers of ICU hospitalized patients during a pandemic, impact test validity and the need for implementation. Conclusions Both tools can be implemented in the ICU with minor requirements. Timely de-isolation improves quality of care and brings cost savings. The need for implementation now is questionable. Regular validation remains a challenge due to ever-changing circumstances.

ABSTRACT Current laboratory protocols for periprosthetic joint infections (PJIs) involve a standard 10- to 14-day incubation period. However, recent evidence indicates considerable variability in the time to diagnosis (TTD) between acute and chronic PJIs. TTD is also influenced by the employed culture media and sample types. Enriched liquid media, such as broths and blood culture bottles, along with sonication fluid culture, are commonly used, though their incremental benefit for PJI diagnosis remains debated. We retrospectively analyzed 187 confirmed hip and knee PJIs, each with at least three intraoperative samples. Comparison of TTD among early acute ( n = 68), late acute ( n = 52), and late chronic ( n = 67) PJIs revealed a significant difference, particularly between late acute and late chronic infections ( P < 0.004). Early acute and late acute PJIs were diagnosed within 5 days in 97.1% and 98.1% of cases, respectively, contrasting with 14 days required for 97.1% of late chronic PJIs. Enriched liquid media significantly improved species detection, especially in polymicrobial and anaerobic infections. Pediatric and anaerobic blood culture bottles demonstrated superior efficacy over thioglycolate broths for diagnostic confirmation. Sonication fluid culture was essential for confirming diagnoses in 17.6% of cases. Our findings highlight that clinical presentation, rather than time since primary arthroplasty, should guide incubation duration: both early acute and late acute PJIs can be diagnosed within 5 days. Medical microbiology laboratories should consider shorter incubation times for acute PJIs to optimize diagnostic efficiency. The use of blood culture bottles and sonication fluid culture proves invaluable for accurate PJI diagnosis. IMPORTANCE While molecular techniques are becoming increasingly employed, culture remains the gold standard for diagnosing periprosthetic joint infections. However, guidance for laboratory protocols is limited and highly variable. This article aims to increase diagnostic efficiency by providing concrete recommendations for medical microbiology laboratories.

IntroductionProsthetic joint infections (PJI) affect 1-3% of prosthetic joint replacements, frequently linked to biofilm formation on implant surfaces. PJIs account for 13.0-31.3% of all revision surgeries. As treatment is not always successful, prevention remains critical. Currently, silver based antimicrobial coatings are justified in select high-risk arthroplasty cases, restricted to metal surfaces. An antibacterial silver multilayer coating (SML) has been developed for implant materials: titanium alloy (Ti) and cobalt-chromium-molybdenum alloy (CoCr), often used in hip or knee prostheses. The SML coating is intended for revision implants, which are often required due to infection related implant failure. This study investigates the antibacterial performance of the SML coating across different surfaces and implant materials, using multiple bacterial strains not previously investigated to this extent.MethodsAntibacterial efficacy of the SML coating was assessed by quantifying colony forming units (CFU) reduction on Ti6Al4V and Co28Cr6M discs with three different surfaces (polished and two grades of corundum blasted (CB)). In vitro standardized testing followed ISO 22196, JIS Z-2801, and ASTM E-2180 standards using American Type Culture Collection (ATCC) strains Pseudomonas aeruginosa ATCC15442, Staphylococcus aureus ATCC6538p, Staphylococcus epidermidis ATCC35984, Pseudomonas aeruginosa ATCC15442, and Escherichia coli ATCC8739. Two groups were tested: non-SML-coated samples and SML-coated samples. After 24 hours incubation in viscous nutrient broth at 37°C, viable bacteria were quantified per disc after sonication in neutralizing broth and CFU enumeration.ResultsAcross all materials and strains, the SML coating achieved >99.2% and >0.9-4.0 CFU log10 reduction in viable bacteria compared to the non-SML-coated controls. Material-dependent effects were observed for each of the bacterial species analyzed. S. aureus and E. coli exhibited more CFUs on Ti than on CoCr. The CoCr CB surface yielded the lowest level of bacterial growth for P. aeruginosa ATCC15442, whereas S. epidermidis colonized the Ti CB surface more extensively.Discussion and conclusionThese findings demonstrate a thorough and broad-spectrum antibacterial activity of the SML coating across diverse implant materials and surface textures. Future studies will focus on testing clinical PJI isolates in both in vitro and in vivo models to further evaluate the translational potential of the SML coating for prevention of bacterial colonization in joint arthroplasty.

Home-based sexual health care (including self-sampling testing) could reduce barriers to clinic-based testing. This study systematically evaluated the implementation of home-based sexual health care ('Limburg4Zero') among men who have sex with men (MSM) in a mixed urban-rural region of the Netherlands. We systematically assessed implementation outcomes (contextual domains, population reached, effectiveness, adoption by health care providers (HCP), implementation fidelity, and maintenance) using the practical, robust implementation and sustainability model. We used a mixed-methods research design that combined survey and in-depth interview data from our priority population (MSM) and implementers with insights from our community advisory board and field notes from monthly meetings with the implementers. Of 1076 requested tests, 906 MSM received a (self-sampling STI/HIV) test kit and sexual health information. Most participants (median age 31) had a university or college degree and had a Western ethnicity. The return rate for laboratory testing was 67%. Home-based care participants more often never tested HIV before (39%) compared to STI clinic attendees (28%). Adoption by HCP was highly acceptable, although perceived pragmatic and technical challenges were experienced. Key elements of the home-based care service were implemented as designed, with co-created adjustments for optimization during the implementation. Maintaining the innovation in the long term was desirable, although future recommendations for efficient continuation should be considered. Implementation of home-based sexual health care has demonstrably increased care accessibility for MSM who had never previously been tested. Therefore, a systematic approach is crucial to foster the impact of home-based sexual health care.

Objectives:In the Netherlands, tuberculosis (TB) screening is mandatory for migrants from high incidence countries (>200 cases/100,000). These regions often have elevated rates of hepatitis B (HBV), hepatitis C (HCV) and HIV. The INTEGREAT-study assessed the feasibility and acceptability of integrating point-of-care testing (POCT) for these infections into existing TB screening, in line with UN Sustainable Development Goals. Study design:A mixed-methods study design was used. Methods:This study offered POCT using finger-prick blood and a brief medical history questionnaire during the public health TB screening. Quantitative data were analysed descriptively. Qualitative data from four focus groups with healthcare workers evaluating implementation were deductively and inductively coded. Results:Of 293 eligible individuals, 231 (78.8 %) participated. Participants (51.1 % male, mean age 31.9 years) originated from India (27.7 %), South Africa (24.7 %), Pakistan (7.4 %), and other countries (40.2 %). Three participants (1.3 %) tested positive for HIV or HBV and were referred to care if appropriate. Most participants (90 %) preferred finger-prick POCT over venipuncture. Focus groups highlighted the importance of a clear protocol and skilled staff for successful implementation. Conclusions:This study demonstrated the feasibility and acceptability of integrating POCT into TB screening, although the number of infections was low. Careful follow-up remains essential to ensure effective care.

Intensive care unit (ICU) patients with COVID-19 are isolated until two subsequent SARS-CoV-2 PCR tests have become negative. The question is whether the viral RNA detected here represents intact or compromised viral particles. A viability PCR method detects only intact infectious viruses and disregards RNA from incomplete non-infectious viruses or RNA remnants. We hypothesize that the time to a negative PCR is shorter using the viability PCR compared to conventional SARS-CoV-2 PCR. Patients admitted to the ICU in the Maastricht University Medical Center within an ongoing prospective cohort were included, and respiratory samples were collected three times weekly. Samples were aliquoted for viability PCR into two aliquots, one of which was treated with propidium monoazide (PMA) to eliminate incomplete viruses. The PMA-untreated sample corresponded to the traditional SARS-CoV-2 PCR used in routine diagnostics. A mean time difference between viability and conventional PCR was estimated, assuming a negative binomial distribution. One hundred two ICU patients were included in the analysis. The time to a negative PCR test result differed significantly between viability PCR and conventional PCR (Paired Prentice-Wilcoxon test P-value = 0.0001). On average, the first negative viability PCR test result occurred 2.4 days (95% CI 1.5-4.2) before the first negative conventional PCR test result. The application of a viability PCR technique for SARS-CoV-2 provided an earlier indication of the absence of intact virus, suggesting reduced infectivity, potentially enabling earlier de-isolation of ICU patients. IMPORTANCE:This study demonstrated that, within patients, on average, viability PCR became negative 2.4 days earlier than conventional PCR, indicating that viability PCR could potentially assist in de-isolating patients 2.4 days earlier. Future use of this assay could thus aid in improving routine COVID-19 diagnostics and prognostics related to the timing of de-isolation. Additionally, future development of a similar approach for other respiratory viruses could be of interest.

Undetected chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections can lead to cirrhosis and liver cancer. Syrian migrants are the largest non-European migrant group in the Netherlands with HBV and HCV prevalence rates above 2%. This study aimed to reach Syrian migrants for HBV and HCV testing using point-of-care tests (POCT). A multifaceted strategy was employed to reach Syrian migrants aged ≥16 years from two Dutch municipalities for free-of-charge HBsAg and anti-HCV POCT using finger prick blood at the regional Public Health Service. All were personally invited by the Public Health Service by postal mail, based on municipal registry data. Respondents' medical history data were analysed descriptively and data on age, sex, and municipality were compared with non-participating invitees, using Pearson's Chi-square test. Of the study population (N = 832), 32.3% (n = 269) attended the testing. The mean age of participants was 36 years (range 16-70), 59.1% were men, and 66.5% were unemployed. Non-participation was higher in the younger age groups (<30 years) (p < .001). The POCT using finger prick blood was well received. None tested HBsAg or anti-HCV positive. With approximately one-third of participation, this study demonstrated relatively high reach of Syrian migrants for testing, compared to studies with similar recruitment methods. However, while the reach could be considered successful, testing failed to demonstrate new infection in this key population. Thereby, other methods may be preferred to identify new HBV and HCV infections, such as opportunistic testing within existing care processes.

ABSTRACT Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). Commonly used methods for both clinical diagnosis of SARS-CoV-2 infection and management of infected patients involve the detection of viral RNA, but the presence of infectious virus particles is unknown. Viability PCR (v-PCR) uses a photoreactive dye to bind non-infectious RNA, ideally resulting in the detection of RNA only from intact virions. This study aimed to develop and validate a rapid v-PCR assay for distinguishing intact and compromised SARS-CoV-2. Propidium monoazide (PMAxx) was used as a photoreactive dye. Mixtures with decreasing percentages of intact SARS-CoV-2 (from 100% to 0%) were prepared from SARS-CoV-2 virus stock and a clinical sample. Each sample was divided into a PMAxx-treated part and a non-PMAxx-treated part. Reverse transcription-PCR (RT-PCR) using an in-house developed SARS-CoV-2 viability assay was then applied to both sample sets. The difference in intact SARS-CoV-2 was determined by subtracting the cycle threshold ( Ct ) value of the PMAxx-treated sample from the non-PMAxx-treated sample. Mixtures with decreasing concentrations of intact SARS-CoV-2 showed increasingly lower delta Ct values as the percentage of intact SARS-CoV-2 decreased, as expected. This relationship was observed in both high and low viral load samples prepared from cultured SARS-CoV-2 virus stock, as well as for a clinical sample prepared directly from a SARS-CoV-2 positive nasopharyngeal swab. In this study, a rapid v-PCR assay has been validated that can distinguish intact from compromised SARS-CoV-2. The presence of intact virus particles, as determined by v-PCR, may indicate SARS-CoV-2 infectiousness. IMPORTANCE This study developed a novel method that can help determine whether someone who has been diagnosed with coronavirus disease 2019 (COVID-19) is still capable of spreading the virus to others. Current tests only detect the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA, but cannot tell whether the particles are still intact and can thus infect cells. The researchers used a dye that selectively blocks the detection of damaged virions and free RNA. They showed that this viability PCR reliably distinguishes intact SARS-CoV-2 capable of infecting from damaged SARS-CoV-2 or free RNA in both cultured virus samples and a clinical sample. Being able to quickly assess contagiousness has important implications for contact tracing and safely ending isolation precautions. This viability PCR technique provides a simple way to obtain valuable information, beyond just positive or negative test results, about the actual risk someone poses of transmitting SARS-CoV-2 through the air or surfaces they come into contact with.

OBJECTIVES:The present study examines the temporal association between the changes in SARS-CoV-2 viral load during infection and whether the CoLab-score can facilitate de-isolation. METHODS:Nasal swabs and blood samples were collected from ICU-admitted SARS-CoV-2 positive patients at Maastricht UMC+ from March 25, 2020 to October 1, 2021. The CoLab-score was calculated based on 10 blood parameters and age and can range from -43 to 6. Three mixed effects analyses compared patient categories based on initial PCR Ct values (low; Ct≤20, mid; 20>Ct≤30, high; Ct>30), serial PCR Ct values to CoLab-scores over time, and the association between within-patient delta Ct values and CoLab-scores. RESULTS:In 324 patients, the median Ct was 33, and the median CoLab-score was -1.78. Mid (n=110) and low (n=41) Ct-categories had higher CoLab-scores over time (+0.60 points, 95 % CI; 0.04-1.17, and +0.28 points, 95 % CI -0.49 to 1.04) compared to the high Ct (n=87) category. Over time, higher serial Ct values were associated with lower serial CoLab-scores, decreasing by -0.07 points (95 % CI; -0.11 to -0.02) per day. Increasing delta Ct values were associated with a decreasing delta CoLab-score of -0.12 (95 % CI; -0.23; -0.01). CONCLUSIONS:The study found an association between lower viral load on admission and reduced CoLab-score. Additionally, a decrease in viral load over time was associated with a decrease in CoLab-score. Therefore, the CoLab-score may make patient de-isolation an option based on the CoLab-score.

With the emergence of highly transmissible variants of concern, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still poses a global threat of coronavirus disease 2019 (COVID-19) resurgence. Cellular responses to novel variants are more robustly maintained than humoral responses, and therefore, cellular responses are of interest in assessing immune protection against severe disease in the population. We aimed to assess cellular responses to SARS-CoV-2 at the population level. IFNγ (interferon γ) responses to wild-type SARS-CoV-2 were analyzed using an ELISpot assay in vaccine-naive individuals with different humoral responses: Ig (IgM and/or IgG) seronegative (n = 90) and seropositive (n = 181) with low (<300 U/mL) or high (≥300 U/mL) humoral responses to the spike receptor binding domain (anti-S-RBD). Among the seropositive participants, 71.3% (129/181) were IFNγ ELISpot positive, compared to 15.6% (14/90) among the seronegative participants. Common COVID-19 symptoms such as fever and ageusia were associated with IFNγ ELISpot positivity in seropositive participants, whereas no participant characteristics were associated with IFNγ ELISpot positivity in seronegative participants. Fever and/or dyspnea and anti-S-RBD levels were associated with higher IFNγ responses. Symptoms of more severe disease and higher anti-S-RBD responses were associated with higher IFNγ responses. A significant proportion (15.6%) of seronegative participants had a positive IFNγ ELISpot. Assessment of cellular responses may improve estimates of the immune response to SARS-CoV-2 in the general population. IMPORTANCE:Data on adaptive cellular immunity are of interest to define immune protection against severe acute respiratory syndrome coronavirus 2 in a population, which is important for decision-making on booster-vaccination strategies. This study provides data on associations between participant characteristics and cellular immune responses in vaccine-naive individuals with different humoral responses.

IntroductionCross-border mobility (CBM) to visit social network members or for everyday activities is an important part of daily life for citizens in border regions, including the Meuse-Rhine Euroregion (EMR: neighboring regions from the Netherlands, Belgium, and Germany). We assessed changes in CBM during the COVID-19 pandemic and how participants experienced border restrictions.MethodsImpact of COVID-19 on the EMR’ is a longitudinal study using comparative cross-border data collection. In 2021, a random sample of the EMR-population was invited for participation in online surveys to assess current and pre-pandemic CBM. Changes in CBM, experience of border restrictions, and associated factors were analyzed using multinomial and multivariable logistic regression analysis.ResultsPre-pandemic, 82% of all 3,543 participants reported any CBM: 31% for social contacts and 79% for everyday activities. Among these, 26% decreased social CBM and 35% decreased CBM for everyday activities by autumn 2021. Negative experience of border restrictions was reported by 45% of participants with pre-pandemic CBM, and was higher (p < 0.05) in Dutch participants (compared to Belgian; aOR= 1.4), cross-border [work] commuters (aOR= 2.2), participants with cross-border social networks of friends, family or acquaintances (aOR= 1.3), and those finding the measures ‘limit group size’ (aOR= 1.5) and ‘minimalize travel’ (aOR= 2.0) difficult to adhere to and finding ‘minimalize travel’ (aOR= 1.6) useless.DiscussionCBM for social contacts and everyday activities was substantial in EMR-citizens, but decreased during the pandemic. Border restrictions were valued as negative by a considerable portion of EMR-citizens, especially when having family or friends across the border. When designing future pandemic control strategies, policy makers should account for the negative impact of CBM restrictions on their citizens.

BACKGROUND:Home-based sampling could create accessible testing opportunities for men who have sex with men (MSM) who use pre-exposure prophylaxis (PrEP). Blood collection is required for the most reliable laboratory results for HIV and syphilis testing. An innovative blood collection method (Tasso+) creates a vacuum and semi-automatically collects larger volumes of blood from the upper arm. This study aimed to assess acceptability and feasibility of this device among PrEP-using MSM and the performance of blood collection. METHODS:Between August 2022 and January 2023, 47 MSM were recruited during their routine PrEP consultations at a Dutch Centre for Sexual Health. Participants tested the method directly after consultation, and an online questionnaire determined acceptability and feasibility. Blood and residual serum volumes were measured after sampling and after HIV and syphilis testing. RESULTS:Of the participants, 87% had a positive attitude toward use of the device, and 77% would use it again for self-sampling at home. Participants rated the use of the blood collection device as easy (96%). On average, 536 μL whole blood (244 μL serum) was collected. All samples were tested for HIV and syphilis, and most samples had sufficient blood for routine HIV (91%) and syphilis testing (89%). Most samples (85%) had 220 μL residual blood, sufficient for further testing (e.g., confirmation). CONCLUSIONS:Blood self-sampling with a method that creates a vacuum from the upper arm is highly acceptable by users and performs well in blood collection for multiple tests. This method has promising potential for use in home-based sexual health care for PrEP-using MSM.

BackgroundBorder measures were implemented in many countries as infection prevention measures to interrupt between-country COVID-19 transmission. Border closings impact border region residents, as their professional and social lives are often intertwined across national borders. We studied whether crossing borders to visit family/friends in neighbouring countries (cross-border mobility) was associated with SARS-CoV-2 seroprevalence in Dutch Euregional residents.MethodsSARS-CoV-2 serostatus (negative/positive) was assessed (pre-vaccination) using laboratory testing to determine previous infection. Visiting Belgian or German family/friends in February-March 2020 was questioned. The association between cross-border mobility and seroprevalence was tested using logistic regression analysis, adjusted for previously identified exposure factors.ResultsIn 9,996 participants, 36.8% (n=3,677) reported cross-border family/friends. Of these, one-third (n=1,306) visited their cross-border family/friends in February-March 2020. Multivariable analyses revealed no positive association between cross-border mobility and seropositivity, for both participants living in a border municipality (ORfamily/friends not visited=0.90 [95% CI:0.78-1.04], ORfamily/friends visited=0.88 [95% CI:0.73-1.05]), and for participants not living in a border municipality (ORfamily/friends not visited=0.91 [95% CI:0.72-1.16], ORfamily/friends visited=0.62 [95% CI:0.41-0.94]).ConclusionsThis study provided no evidence of cross-border mobility as an important exposure factor for SARS-CoV-2. The results of our unique real-world study suggest that cross-border mobility did not substantially contribute to cross-border SARS-CoV-2 transmission in the Netherlands.

The CoLab score was developed and externally validated to rule out COVID-19 among suspected patients presenting at the emergency department. We hypothesized a within-patient decrease in the CoLab score over time in an intensive care unit (ICU) cohort. Such a decrease would create the opportunity to potentially rule out the need for isolation when the infection is overcome. Using linear mixed-effects models, data from the Maastricht Intensive Care COVID (MaastrICCht) cohort were used to investigate the association between time and the CoLab score. Models were adjusted for sex, APACHE II score, ICU mortality, and daily SOFA score. The CoLab score decreased by 0.30 points per day (95% CI − 0.33 to − 0.27), independent of sex, APACHE II, and Mortality. With increasing SOFA score over time, the CoLab score decreased more strongly (− 0.01 (95% CI − 0.01 to − 0.01) additional decrease per one-point increase in SOFA score.) The CoLab score decreased in ICU patients on mechanical ventilation for COVID-19, with a one-point reduction per three days, independent of sex, APACHE II, and ICU mortality, and somewhat stronger with increasing multi-organ failure over time. This suggests that the CoLab score would decrease below a threshold where COVID-19 can be excluded.