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The author offers insights on a study published within the issue which examined the link between methicillin-resistant Staphylococcus aureus (MRSA) screening frequency and nosocomial MRSA incidence in hospitals in Germany. Topics discussed include the morbidity and mortality associated with MRSA, the contribution of MRSA hospital admission screening to the decline in MRSA prevalence among patients, and the measurement of MRSA infection risk during hospitalization.

Purpose: Staphylococcus aureus bacteremia (SAB) is associated with a 90-day mortality of 28-34%. Many SAB-patients (7.8-39%) have a secondary S. aureus bacteriuria (SABU) mainly without symptoms of a urinary tract infection. Due to high morbidity and mortality, there is an interest in rapid detection of S. aureus bacteremia. Here, we compared a rapid nucleic acid amplification test (NAAT) with conventional culture to detect S. aureus in urine and to identify cases with increased risk for SAB., Methods: In a cross-sectional study, we assessed urine samples (mid-stream, clean catch and catheter urine) of patients with SAB and bacteremia other than SAB (non-SAB). Urine samples were collected ± 3 days to the collection of the positive blood culture and were cultured on a set of selective and non-selective agar plates. NAAT was performed using a commercial test (Xpert ® SA Nasal Complete G3, Cepheid) from a sterile swab soaked in urine., Results: We included samples from 100 patients (68% male, median age: 67.4 years) with SAB and 20 patients (75% male, median age: 65.84 years) with non-SAB. The sensitivity of detecting SAB from urine samples was 47% (specificity: 90%) for NAAT, when applying a Ct-value of ≤ 37.4 for positive results. Urine culture had a sensitivity of 25% and a specificity of 95%. Molecular and culture methods showed a moderate agreement (80%, Cohens kappa: 0.55)., Conclusion: NAAT from urine has a higher sensitivity than culture in patients with SAB and could potentially identify cases with increased risk for SAB. Future studies should investigate whether this characteristic could translate into a clinical benefit through rapid detection of SAB., (© 2024. The Author(s).)

Malaria rapid diagnostic tests (RDTs), which detect Plasmodium falciparum (Pf)-specific histidine-rich protein-2 (HRP2), have increasing importance for the diagnosis and control of malaria, especially also in regions where routine diagnosis by microscopy is not available. HRP2-based RDTs have a similar sensitivity to expert microscopy, but their reported low specificity can lead to high false positivity rates, particularly in high-endemic areas. Despite the widespread use of RDTs, models investigating the dynamics of HRP2 clearance following Pf treatment focus rather on short-term clearance of the protein. The goal of this observational cohort study was to determine the long-term kinetic of HRP2-levels in peripheral blood after treatment of uncomplicated malaria cases with Pf mono-infection using a 3-day course of artesunate/amodiaquine. HRP2 levels were quantified at enrollment and on days 1, 2, 3, 5, 7, 12, 17, 22, and 28 post-treatment initiation. The findings reveal an unexpectedly prolonged clearance of HRP2 after parasite clearance from capillary blood. Terminal HRP2 half-life was estimated to be 9 days after parasite clearance using a pharmacokinetic two-compartmental elimination model. These results provide evidence that HRP2 clearance has generally been underestimated, as the antigen remains detectable in capillary blood for up to 28 days following successful treatment, influencing RDT-based assessment following a malaria treatment for weeks. A better understanding of the HRP2 clearance dynamics is critical for guiding the diagnosis of malaria when relying on RDTs., Importance: Detecting Plasmodium falciparum , the parasite responsible for the severest form of malaria, typically involves microscopy, polymerase chain reaction (PCR), or rapid diagnostic tests (RDTs) targeting the histidine-rich protein 2 or 3 (HRP2/3). While microscopy and PCR quickly turn negative after the infection is cleared, HRP2 remains detectable for a prolonged period. The exact duration of HRP2 persistence had not been well defined. Our study in Gabon tracked HRP2 levels over 4 weeks, resulting in a new model for antigen clearance. We discovered that a two-compartment model accurately predicts HRP2 levels, revealing an initial rapid reduction followed by a much slower elimination phase that can take several weeks. These findings are crucial for interpreting RDT results, as lingering HRP2 can lead to false positives, impacting malaria diagnosis and treatment decisions., Competing Interests: The authors declare no conflict of interest.

The Panton-Valentine leukocidin (PVL) of Staphylococcus aureus is associated with necrotizing infections. After binding to complement 5a receptor (C5aR/CD88) and CD45 it causes cytolysis in polymorphonuclear neutrophils (PMNs) as well as inflammasome activation in monocytes. The objective of this study was to test if (ant)agonists of C5aR and CD45 can attenuate the effect of PVL on PMNs and monocytes. We tested the effect of various concentrations of six C5aR (ant)agonists (avacopan, BM213, DF2593A, JPE-1375, PMX205 and W-54011) and one CD45 antagonist (NQ301) to attenuate the cytotoxic effect of PVL on human PMNs and monocytes in vitro. Shifts in the half-maximal effective concentration (EC 50 ) of PVL to achieve a cytotoxic effect on PMNs and modulation of inflammatory cytokine response from monocytes were determined by flow cytometry and IL-1β detection. Pre-treatment of PMNs with avacopan, PMX205 and W-54,011 resulted in 3.6- to 4.3-fold shifts in the EC 50 for PVL and were able to suppress IL-1β secretion by human monocytes in the presence of PVL. BM213, DF2593A and NQ301 were unable to change the susceptibility of PMNs towards PVL or reduce inflammasome activation in monocytes. Avacopan, PMX205 and W-54,011 showed protection against PVL-induced cytotoxicity and suppressed IL-1β secretion by monocytes. Clinical studies are needed to prove whether these substances can be used therapeutically as repurposed drugs., (© 2024. The Author(s).)

Background: The detection of causative pathogens plays a crucial role in the diagnosis and targeted treatment of periprosthetic joint infections (PJI). While there have been improvements in analytic methods in the past, pre-analytical procedures have not yet been sufficiently investigated. The objective of this study was to compare the culture yield of four different pre-analytical procedures., Methods: Patients with perioperative diagnosis of PJI were included in a single center cross-sectional study (2021-2022). Tissue samples (n = 20) of each patient were randomly and equally distributed to each of the four study arms. Tissue samples were either send to the laboratory without culture medium (group A) or were transported in thioglycolate medium immediately after sampling at three different temperatures (room temperature, 4 °C, 37° for 24 h; group B-D). Culture media were investigated for growth on days 1, 3, 7, 12, 14. All organisms, the number of positive samples and the time to positivity were recorded and compared between the study arms. Single positive cultures were considered as contamination., Results: In total, 71 patients were included. The proportions of culture negative samples (10-15%) and polymicrobial infections (51-54%) were comparable between the four arms. Seven patients (10%) were culture-negative in group A, but showed growth in thioglycolate media (group B-D). Furthermore, 13% of patients showed growth in all groups, but additional organisms were cultured in thioglycolate. There was growth beyond day 7 of culturing only in thioglycolate, but not in group A. A storage temperature of 4 °C showed a longer time to positivity compared to the other groups (p < 0.001)., Conclusions: Pre-analytical storage of tissue samples in thioglycolate broth did not improve the culture yield and did not detect additional cases of infection compared to the standard (pre-analytical storage in sterile containers). However, including a thioglycolate medium to the sampling algorithm reduced the rate of culture-negative infections and helped to identify additional organisms., (© 2024. The Author(s).)

Introduction. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) specifies the agar depth (4±0.5 mm) when performing antimicrobial susceptibility testing (AST). Since the infrastructure to produce standardized agar may be lacking in settings with limited resources, we wanted to examine to what extent variation in agar depth affects the inhibition zone diameters of quality control (QC) strains and AST of clinical isolates. Methods. The inhibition zone diameters on Mueller-Hinton II agar with different depths (2-6 mm) were tested for various QC strain-antimicrobial agent combinations using Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 29213. The relationship between zone diameters at different agar depths and MICs was investigated for 35 clinical isolates ( E. coli , Klebsiella pneumoniae , S. aureus and P. aeruginosa ) from Sierra Leone using MICs as the reference. Results. The inhibition zone diameters were within the acceptance ranges as defined by the EUCAST for the majority of QC strains and antimicrobials, independent of the agar depth. At extreme agar depths, inhibition zones were more frequently out of range. The accuracy of AST varied for clinical isolates at different agar depths for categorical agreement (85.8-94.6%), major error rate (0.4-2.1%) and very major error rate (VME: 3.3-12.5%). Conclusions. Even if the QC strains were in the acceptance range at different agar depths, this does not rule out unacceptably high VME rates (>3%) in clinical isolates.

We evaluated the Nugent score against a multiplex real-time PCR (reference) for diagnosing bacterial vaginosis (BV) in 140 pregnant women. The Nugent score had a sensitivity of 60 %, a specificity of 81 % and a negative predictive value of 92 % - therefore a tool to rule out BV in pregnant women., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

We present a patient who suffered an agricultural rollover trauma and developed a fracture-associated tissue infection caused by Mycobacterium smegmatis. Since cases are rare, treatment of infections with M. smegmatis requires an interprofessional approach and the combination of surgery and adjunctive antimicrobial treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Seasonal increase of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus A/B (Flu A/B), and respiratory syncytial virus (RSV) require rapid diagnostic test methods for the management of respiratory tract infections. In this study, we compared the diagnostic accuracy of Savanna RVP4 (RVP4, QuidelOrtho) with Xpert Xpress Plus SARS-CoV-2/Flu/RSV (Xpert, Cepheid). Nasopharyngeal swabs from patients treated at a tertiary care hospital (Germany) were tested for SARS-CoV-2, Flu A/B, and RSV by RVP4 to assess diagnostic accuracy (reference standard: Xpert). The intra and inter assay precision of Ct-values was assessed by repeated test in triplicates (on day 1) and duplicates (days 2-3). All patients with a physician's order for a multiplex test for SARS-CoV-2, Flu, and RSV test were included. Duplicate swabs from the same patient, samples with a total volume ≤1 mL, or inappropriate shipment/storage were excluded. In total, 229 swabs were included between September 2023 and February 2024. The concordance between both tests was 96.5% (SARS-CoV-2), 98.7% (Flu A), and 99.6% (RSV). Flu B was not detected by both tests. The RVP4 test had a sensitivity of 85%-95% and a specificity of 100% for the detection of SARS-CoV-2, Flu A, and RSV. The intra and inter assay precision of Ct-values from RVP4 was 3% and 2% (SARS-CoV-2), 5% and 4% (Flu A), and 0% and 3% (RSV), respectively. The Savanna RVP4 has a favorable diagnostic accuracy for the detection of SARS-CoV-2, Flu A, and RSV., Importance: We assessed the diagnostic accuracy of a new point-of-care test for the rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus A/B (Flu A/B), and respiratory syncytial virus (RSV). The new test has a concordance with the reference standard of 96.5% (SARS-CoV-2), 98.7% (Flu A), and 99.1% (RSV). The sensitivity of 85%-95% and specificity of 100% for the detection of SARS-CoV-2, Flu A, and RSV is comparable with similar nucleic acid amplification-based point of care tests but at lower costs., Competing Interests: The authors declare no conflict of interest.

To have an impact on the mortality of bloodstream infections, microbiological diagnostics of blood cultures (BC) should provide first results within 12 h. Here, we show how a decentralized BC incubation connected to the central BC incubators via a browser-based application significantly reduces turnaround times., Competing Interests: Declaration of Competing Interest All authors report no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of mortality due to bacterial antimicrobial resistance. While S. aureus is common in skin and soft tissue infections (SSTI) in Africa, data on MRSA rates are scarce and reports vary widely across the continent (5%-80%). In this study, we describe the proportion of MRSA causing SSTI in Lambaréné, Gabon, over an 11-year period., Methods: We retrospectively analyzed data from 953 bacterial specimens collected from inpatients and outpatients with SSTI at the Albert Schweitzer Hospital, Lambaréné, Gabon, between 2009 and 2019. We determined temporal changes in the prevalence of MRSA and identified risk factors for SSTI with MRSA., Results: 68% of all specimens with bacterial growth yielded S. aureus (n = 499/731), of which 7% (36/497) with antimicrobial susceptibility testing were identified as MRSA. Age above 18 years, admission to the surgical ward, and deep-seated infections were significantly associated with MRSA as the causative agent. After an initial decline from 7% in 2009, there was a marked increase in the proportion of MRSA among all S. aureus from SSTI from 3 to 20% between 2012 and 2019. The resistance rate to erythromycin was significantly higher in MRSA than in methicillin-susceptible S. aureus (73% vs. 10%), and clindamycin resistance was detected exclusively in MRSA isolates (8%)., Conclusion: The increasing proportion of MRSA causing SSTI over the 11-year period contrasts with many European countries where MRSA is on decline. Continuous surveillance of MRSA lineages in the hospital and community along with antibiotic stewardship programs could address the increasing trend of MRSA., (© 2024. The Author(s).)

Background: Long-term immunity following yellow fever vaccination remains controversial. We aimed to summarise the literature regarding the long-term protection (≥10 years) conveyed by a single dose of yellow fever vaccination., Methods: In this systematic review and meta-analysis, we searched 11 databases from database inception to Aug 24, 2023. We included cohort and cross-sectional studies reporting immunogenicity outcomes for children or adults who received a single dose of yellow fever vaccination 10 or more years ago. Case series and single case reports were excluded. Participants who received more than one dose of yellow fever vaccination before measurement of the outcome were excluded. Identified records were reviewed by two independent reviewers. The primary outcome of the meta-analysis was the pooled seroprotection rate. Risk of bias was assessed with the Risk Of Bias In Non-randomized Studies of Interventions tool, and the Joanna Briggs Institute tool for analytical cross-sectional studies. Studies of moderate or good quality that reported seroprotection were included for random-effects meta-analysis and stratified by endemicity and specific risk groups. The study was registered with PROSPERO, CRD42023384087., Findings: Of the 7363 articles identified by our search, 39 were eligible for inclusion for systematic review. These studies comprised 2895 individuals vaccinated 10-60 years ago. 20 studies were included in the meta-analysis. Pooled seroprotection rates were 94% (95% CI 86-99) among healthy adults in a non-endemic setting (mostly travellers) and 76% (65-85) in an endemic setting (all Brazilian studies). The pooled seroprotection rate was 47% (35-60) in children (aged 9-23 months at time of vaccination) and 61% (38-82) in people living with HIV. Reported criteria for seroprotection were highly heterogeneous., Interpretation: The gathered evidence suggests that a single dose of yellow fever vaccination provides lifelong protection in travellers. However, in people living with HIV and children (younger than 2 years), booster doses might still be required because lower proportions of vaccinees were seroprotected 10 or more years post-vaccination. Lower observed seroprotection rates among residents of endemic areas were partly explained by the use of a higher cutoff for seroprotection that was applied in Brazil. Studies from sub-Saharan Africa were scarce and of low quality; thus no conclusions could be drawn for this region., Funding: None., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: Antibacterial prophylaxis in children and adolescents undergoing allogeneic hematopoietic cell transplantation (HCT) is controversial and not recommended by international guidelines. We analyzed relevant posttransplant outcomes following discontinuation of antibacterial prophylaxis at a major European pediatric transplant center., Methods: The single-center retrospective audit included all pediatric allogeneic HCT patients (pts) transplanted between 2011 and 2020 before (≤2014) and after (≥2015) stopping routine antibacterial prophylaxis with penicillin, metronidazole, and ciprofloxacin upon start of the conditioning regimen. The primary endpoint was overall survival until the first hospital discharge. Secondary endpoints included the occurrence of fever; bacterial infections; and cumulative days with antibacterial agents until discharge., Results: A total of 257 HCT procedures were performed in 249 pts (median age: 10 years, range, 0.2-22.5) for leukemia/lymphoma (n = 150) and nonmalignant disorders (n = 107). Of these, 104 procedures were performed before (cohort 1) and 153 after (cohort 2) stopping prophylaxis. Overall survival until discharge was 90.4% in cohort 1 and 96.1% in cohort 2 (p = .06). No differences were observed in the occurrence of fever (92.3 vs. 94.1%; p = .57) and bacterial infections (34.6 vs. 25.5%; p = .11). The median number of days on antibacterial agents was significantly lower in cohort 2 (39 vs. 34; p = .002). Detection rates of resistant organisms were overall low., Conclusion: In this single-center audit, the stop of routine antibacterial prophylaxis had no effect on the occurrence of fever, bacterial infections, resistant organisms, and GVHD. Overall antibiotic use was significantly reduced, and survival was noninferior to the historical control cohort., (© 2023 The Authors. Transplant Infectious Disease published by Wiley Periodicals LLC.)

Easy access to antimicrobial resistance data and meaningful visualization is essential to guide the empirical antimicrobial treatment and to promote the rational use of antimicrobial agents. Currently available solutions are commonly externally hosted, centralized systems. However, there is a need for close monitoring by local analysis tools. To fill this gap, we developed GEFAAR-a generic framework for the analysis of antimicrobial resistance data. Following the example of the German Robert Koch Institute (RKI), an interactive web-application is provided to determine basic pathogen and resistance statistics. In addition to the RKI's externally maintained database, our application provides a generic framework to import tabular data and to analyze them safely in a local environment. Moreover, our application offers an intuitive web-based user interface to visualize resistance trend analysis as well as advanced cluster analyses on species- or clinic/unit level to generate alerts of potential transmission events., (© 2023. Springer Nature Limited.)

Wildlife can be a reservoir and source of zoonotic pathogens for humans. For instance, pangolins were considered one of the potential animal reservoirs of SARS-CoV-2. The aim of this study was to assess the prevalence of antimicrobial-resistant species (e.g., extended-spectrum β-lactamase [ESBL]-producing Enterobacterales ) and Staphylococcus aureus-related complex and to describe the bacterial community in wild Gabonese pangolins. The pharyngeal colonization of pangolins sold in Gabon ( n  = 89, 2021 to 2022) was analyzed using culture media selective for ESBL-producing Enterobacterales , S. aureus-related complex, Gram-positive bacteria and nonfermenters. Phylogenetic analyses of ESBL-producing Enterobacterales was done using core-genome multilocus sequence typing (cgMLST) and compared with publicly available genomes. Patterns of cooccurring species were detected by network analysis. Of the 439 bacterial isolates, the majority of species belonged to the genus Pseudomonas ( n  = 170), followed by Stenotrophomonas ( n  = 113) and Achromobacter ( n  = 37). Three Klebsiella pneumoniae isolates and one Escherichia coli isolate were ESBL-producers, which clustered with human isolates from Nigeria (MLST sequence type 1788 [ST1788]) and Gabon (ST38), respectively. Network analysis revealed a frequent cooccurrence of Stenotrophomonas maltophilia with Pseudomonas putida and Pseudomonas aeruginosa. In conclusion, pangolins can be colonized with human-related ESBL-producing K. pneumoniae and E. coli. Unlike in other African wildlife, S. aureus-related complex was not detected in pangolins. IMPORTANCE There is an ongoing debate if pangolins are a relevant reservoir for viruses such as SARS-CoV-2. Here, we wanted to know if African pangolins are colonized with bacteria that are relevant for human health. A wildlife reservoir of antimicrobial resistance would be of medical relevance in regions were consumption of so-called bushmeat is common. In 89 pangolins, we found three ESBL-producing Klebsiella pneumoniae strains and one ESBL-producing Escherichia coli strains, which were closely related to isolates from humans in Africa. This points toward either a transmission between pangolins and humans or a common source from which both humans and pangolins became colonized., Competing Interests: The authors declare no conflict of interest.

The detection of nucleic acids as specific markers of infectious diseases is commonly implemented in molecular biology laboratories. The translation of these benchtop assays to a lab-on-a-chip format demands huge efforts of integration and automation. The present work is motivated by a strong requirement often posed by molecular assays that combine isothermal amplification and CRISPR/Cas-based detection: after amplification, a 2-8 microliter aliquot of the reaction products must be taken for the subsequent reaction. In order to fulfill this technical problem, we have designed and prototyped a microfluidic device that is able to meter and aliquot in the required range during the stepped assay. The operation is achieved by integrating a porous material that retains the desired amount of liquid after removing the excess reaction products, an innovative solution that avoids valving and external actuation. The prototypes were calibrated and experimentally tested to demonstrate the overall performance (general fluidics, metering, aliquoting, mixing and reaction). The proposed aliquoting method is fully compatible with additional functions, such as sample concentration or reagent storage, and could be further employed in alternative applications beyond molecular diagnosis.

Chagas disease (CD) affects about 7 million people worldwide, presents a large prevalence in Latin America, and is growing in the rest of the world, where congenital CD is the main mode of transmission. Point-of-care testing (POCT) methods are increasingly required to ease early diagnostics and increase treatment success. This work presents the development and validation of a smartphone-integrated ELISA-based POCT system for the detection of both chronic and congenital CD. Expensive and bulky equipment used for ELISA in conventional laboratories was replaced as follows. A miniaturized device was fabricated for incubation of commercial ELISA plates, achieving ∼±1 °C uniformity and stability. The ELISA plate reader was replaced by smartphone camera and image processing, comprising algorithms to account for variability sources and spatial light non-uniformity; thus, additional hardware like a dark-box is not required. The agreement between samples classified with this novel reading method vs. ELISA plate reader was found to be 99.7% and 95.4% for chronic and congenital CD, respectively. Furthermore, a smartphone application was designed and implemented to guide the user during the assay, provide connectivity, and access databases, facilitating patient monitoring and health-policy making. The whole system is aimed to be used as a practical diagnostic tool in primary health care settings, as well as to facilitate patients' follow-up to provide better treatment. Concerning the technology itself, the proposed POCT platform is versatile enough to be readily adapted for the detection of other infectious diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Staphylococcus aureus bacteremia (SAB) is associated with a high mortality rate. The clinical outcome of SAB patients highly depends on early diagnosis, adequate antibiotic therapy and source control. In the context of the COVID-19 pandemic, the health care system faced additional organizational challenges and the question arose whether structured screening and triaging for COVID-19 and shifting resources influence the management of SAB. Patients ( n = 115) with SAB were enrolled in a retrospective comparative study with historical controls (March 2019-February 2021). The quality of SAB therapy was assessed with a point score, which included correct choice of antibiotic, adequate dosage of antibiotic, sufficient duration of therapy, early start of therapy after receipt of findings, focus search and taking control blood cultures 3-4 days after starting adequate antibiotic therapy. The quality of treatment before and after the onset of the COVID-19 pandemic were compared. No significant differences in the total score points were found between the pre-COVID-19 and COVID-19 cohort. All quality indicators, except the correct duration of antibiotic therapy, showed no significant differences in both cohorts. Furthermore, there were no significant differences in the outcome between both cohorts. The treatment quality of SAB therapy was comparable before and during the COVID-19 pandemic.

Background: Chronic wounds are frequently colonized or infected with multiple bacterial or fungal species, which can both promote or inhibit each other. Network analyses are helpful to understand the interplay of these species in polymicrobial infections. Our aim was to analyse the network of bacterial and fungal species in chronic wounds., Methods: Swabs (n = 163) from chronic wound infections (Masanga, Sierra Leone, 2019-2020) were screened for bacterial and fungal species using non-selective agars. Some of these wounds were suspected but not confirmed Buruli ulcer. Species identification was done with MALDI-TOF mass spectrometry. Network analysis was performed to investigate co-occurrence of different species within one patient. All species with n ≥ 10 isolates were taken into account., Results: Of the 163 patients, 156 had a positive wound culture (median of three different species per patient; range 1-7). Pseudomonas aeruginosa (n = 75) was the dominating species with frequent co-detections of Klebsiella pneumoniae (21 cases; OR = 1.36, 95%CI: 0.63-2.96, p = 0.47), Staphylococcus aureus (14 cases; OR = 1.06, 95%CI: 0.44-2.55, p = 1) and Proteus mirabilis (13 cases; OR = 0.84, 95%CI: 0.35-1.99, p = 0.69)., Conclusion: The culturome of chronic wounds in Sierra Leonean patients is highly diverse and characterized by the co-occurrence of P. aeruginosa, K. pneumoniae and S. aureus., (© 2023. The Author(s).)

Background: Bacterial infections are a major complication for patients undergoing allogeneic hematopoietic stem cell transplantation (HCT). Therefore, protective isolation is considered crucial to prevent nosocomial infections in this population. Here, the impact of intensified contact precautions on environmental contamination and the occurrence of bloodstream infections (BSI) in patients on a HCT unit were compared between two contact precaution measures., Methods: A 2-year retrospective observational study was performed. In the first year, strict contact precaution measures were applied (i.e., protective isolation, the use of sterile personal protective equipment (PPE) by healthcare workers and visitors and sterilization of linen and objects that entered the patient's room). After one year, contact precautions were reduced (i.e., no use of sterile PPE, no sterilization of linen and objects that entered the patient's room). Environmental contamination in randomly selected patient rooms was monitored by sampling six standardized environmental sites in the respective patient treatment units. In a before-and-after study, the number of BSI episodes of those patients, who were accommodated in the monitored rooms was compared., Results: In total, 181 treatment units were monitored. No significant difference in the contamination of anterooms and patient's rooms between both groups was found. A total of 168 patients were followed for the occurrence of BSI during the entire study period (before: 84 patients, after: 84 patients). The total count of patients with BSI episodes showed a higher incidence in the period with reduced contact precautions (30/84 vs. 17/84, p = 0.039). The cause of this increasing number of BSI can be traced back to BSI episodes with common commensal bacteria (17/84 vs. 5/84, p = 0.011)., Conclusions: The implementation of maximal barrier measures did not reduce the bacterial contamination of the patients' environment. The impact on the patients' outcomes remain controversial. Further research is needed to investigate the impact of infection prevention measures on the clinical outcome of patients undergoing HCT., (© 2023. The Author(s).)

We aimed to investigate whether a selective pre-PCR enrichment step improves test performance of RIDA®GENE EHEC/EPEC to detect diarrheagenic Escherichia coli from stool samples. Each of the 250 stool samples was analyzed for the presence of stx1/2 and eae both with and without pre-PCR enrichment in selective broth. In comparison to a reference method, sensitivities for stx1/2 and eae with and without pre-PCR enrichment were 84% (95%CI 70-93) and 89% (stx1/2, 95%CI 76-96), and 71% (95%CI 58-81) and 72% (eae, 95%CI 60-82), respectively. Specificity exceeded 97% for both methods and target genes. In summary, pre-PCR broth enrichment did not improve test performance., Competing Interests: Declaration of Interest The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Bacteria can be associated with male infertility. Antibacterial substances (e.g., zinc-containing proteins, antimicrobial peptides) in ejaculates might impair the growth of bacteria in culture. We therefore wanted to test if removing antibacterial substances by washing the ejaculate could improve the detection of bacteria in culture. All ejaculates from patients ≥18 years old, which were obtained for routine diagnostics to assess male infertility were included in this study (no exclusion criteria were applied). Test samples were diluted with 2 mL sterile 0.45% saline, vortexed, and centrifuged (5 min; 7.5 ×  g ). After the removal of 2 mL of the supernatant and resuspension, 10 μL of the pellet was used for aerobic and anaerobic culture. Control samples were cultured identically but without washing. Species identification was done with matrix-assisted laser desorption ionization-time of flight mass spectrometry. A total of 186 samples were included. The data set was stratified into five groups (Gram-negative rods [GNR], anaerobes [AN], Enterococcus spp. [EC], coagulase-negative staphylococci [CNS], and viridans streptococci [VS]). Compared to the control arm, the test arm revealed significant lower proportions for CNS (59.1% versus 44.6%, P < 0.01) and VS (53.8% versus 41.9%, P = 0.03). Similarly, slightly lower proportions of GNR (16.1% versus 15.1%, P = 0.89), AN (19.9% versus 17.2%, P = 0.5), and EC (25.3% versus 23.1%, P = 0.63) were observed. The medians of CFU were lower in test samples compared to the control samples (6.5 × 10 3 versus 2.5 × 10 3 , P < 0.01) for any bacterial growth. Lower colony counts were also observed for individual bacterial groups. In conclusion, preculture washing of ejaculates results in a decrease in total bacteria count and culture-positive samples. IMPORTANCE This study compares two methods for processing ejaculate samples from men undergoing investigations for infertility. The method of sample washing and centrifugation was compared to the standard method of direct inoculation and culture. The study hypothesis was that preprocessing of samples may increase bacterial yield by removing bactericidal substances from semen. However, we found that washing ejaculate samples before microbiological culture did not improve the detection of bacteria and led to a reduction in colony counts.

Competing Interests: Declaration of competing interest All authors declare no conflict of interest.

Population-based studies of Staphylococcus aureus contribute to understanding the epidemiology of S. aureus infection. We enrolled surgical inpatients admitted to an African tertiary-care hospital in order to prospectively analyze the nosocomial impact of S. aureus . Data collection included an active sampling of the anterior nares and infectious foci within 48 h after admission and subsequently when clinically indicated. All S. aureus isolates were spa and agr genotyped. Possession of Panton-Valentine leukocidin (PVL) and other toxin genes was determined. We analyzed antibiotic susceptibility profiles by VITEK 2 systems and verified methicillin-resistant S. aureus (MRSA) by mecA/C PCR. Among 325 patients, 15.4% carried methicillin-susceptible S. aureus (MSSA) at admission, while 3.7% carried MRSA. The incidence densities of nosocomial infections due to MSSA and MRSA were 35.4 and 6.2 infections per 10,000 patient-days, respectively. Among all 47 nosocomial infections, skin and soft-tissue (40.4%) and bones or joints' (25.5%) infections predominated. Six (12.7%) infection-related S. aureus isolates harbored PVL genes including two (4.2%) MRSA: overall, seventeen (36.2%) isolates carried pyrogenic toxin superantigens or other toxin genes. This study illustrates the considerable nosocomial impact of S. aureus in a Nigerian University hospital. Furthermore, they indicate a need for effective approaches to curtail nosocomial acquisition of multidrug-resistant S. aureus .

Background: The prevalence of Staphylococcus aureus isolates carrying the Panton-Valentine leukocidin (PVL) gene is higher in Africa (≈50%) compared to Europe (< 5%). The study aimed to measure anti-PVL-antibodies in Africans and Germans in a multi-center study and to test whether detected antibodies can neutralize the cytotoxic effect of PVL on polymorphonuclear leukocytes (PMNs)., Methods: Sera from asymptomatic Africans (n = 22, Nigeria, Gabon) and Caucasians (n = 22, Germany) were used to quantify antibody titers against PVL and α-hemolysin (in arbitrary units [AU]) by ELISA. PMNs from one African and German donor were exposed to 5 nM recombinant PVL to measure the neutralizing effect of serial dilutions of pooled sera from African and Caucasian participants, or donor sera at 0.625 and 2.5% (v/v)., Results: Anti-PVL-antibodies were significantly higher in Africans than in Germans (1.9 vs. 0.7 AU, p < 0.0001). The pooled sera from the study participants neutralized the cytotoxic effect of PVL on African and German PMNs in a dose dependent manner. Also, neutralization of PVL on PMNs from the African and German donors had a stronger effect with African sera (half-maximal inhibitory concentration (IC 50 ) = 0.27 and 0.47%, respectively) compared to Caucasian sera (IC 50  = 3.51 and 3.59% respectively)., Conclusion: Africans have higher levels of neutralizing anti-PVL-antibodies. It remains unclear if or at what level these antibodies protect against PVL-related diseases., (© 2022. The Author(s).)

Background: Capnocytophaga canimorsus, a Gram-negative rod, belongs to the Flavobacteriaceae family and colonizes the oropharynx of dogs and cats. Infections with C. canimorsus are rare and can induce a systemic infection with a severe course of the disease. So far, only five case reports of C. canimorsus infections associated with Waterhouse-Friderichsen Syndrome (WFS) have been reported with only two of the patients having a history of splenectomy., Case Presentation: Here, we report a fatal case of WFS due to C. canimorsus bacteremia and mycetal superinfection in a 61-year-old female asplenic patient. Despite extensive therapy including mechanical ventilation, antibiotic coverage with meropenem, systemic corticosteroids medication, vasopressor therapy, continuous renal replacement therapy, therapeutic plasma exchange, multiple transfusions of blood products and implantation of a veno-arterial extracorporeal membrane oxygenation the patient died 10 days after a dog bite. The autopsy showed bilateral hemorrhagic necrosis of the adrenal cortex and septic embolism to heart, kidneys, and liver. Diagnosis of C. canimorsus was prolonged due to the fastidious growth of the bacteria., Conclusions: The occurrence of a severe sepsis after dog bite should always urge the attending physician to consider C. canimorsus as the disease-causing pathogen. A therapeutic regimen covering C. canimorsus such as aminopenicillins or carbapenems should be chosen. However, despite maximum therapy, the prognosis of C. canimorsus-induced septic shock remains very poor. Asplenic or otherwise immunocompromised patients are at higher risk for a severe course of disease and should avoid exposure to dogs and cats and consider antibiotic prophylaxis after animal bite., (© 2022. The Author(s).)

Purpose: Chronic wounds are frequently caused by, or super-infected with, a broad spectrum of bacteria. To guide treatment, healthcare providers need to know the bacterial spectrum and antimicrobial resistance rates to be anticipated. As these data are largely missing for Sierra Leone, we performed a microbiological study on chronic wound infections., Methods: Wound swabs were analysed for bacteria using culture-based methods. Antimicrobial susceptibility testing was done with Vitek2® automated system and EUCAST clinical breakpoints. Selected resistance phenotypes were confirmed by molecular methods (e.g. mecA/C) and genotyping., Results: Of 163 included patients, 156 (95.7%) had a positive wound culture. Pseudomonas aeruginosa (n = 75), Klebsiella pneumoniae (n = 42), Proteus mirabilis (n = 31), Staphylococcus aureus-related complex (n = 31) were predominant. Among Gram-negative rods, resistance rates were high for piperacillin/tazobactam (3-67%), cefotaxime (19-71%), and ciprofloxacin (13-60%). Among isolates of the S. aureus-related complex, 55% were methicillin resistant (CC8, PVL-negative)., Conclusion: The high antimicrobial resistance rates in bacteria from chronic wounds strongly speaks against the use of empirical systemic antibiotic therapy if patients do not show signs of systemic infections, and supports the strategy of local wound care., (© 2022. The Author(s).)

Background: Antimicrobial stewardship (AMS) programmes can improve the use of antimicrobial agents. However, there is limited experience in the implementation of such programmes in low- and middle-income countries (LMICs)., Objectives: To assess the effect of AMS measures in south-east Liberia on the quality of antimicrobial use in three regional hospitals., Methods: A bundle of three measures (local treatment guideline, training and regular AMS ward rounds) was implemented and quality indicators of antimicrobial use (i.e. correct compounds, dosage and duration) were assessed in a case series before and after AMS ward rounds. Primary endpoints were (i) adherence to the local treatment guideline; (ii) completeness of the microbiological diagnostics (according to the treatment guideline); and (iii) clinical outcome. The secondary endpoint was reduction in ceftriaxone use., Results: The majority of patients had skin and soft tissue infections ( n  = 108) followed by surgical site infections ( n  = 72), pneumonia ( n  = 64), urinary tract infection ( n  = 48) and meningitis ( n  = 18). After the AMS ward rounds, adherence to the local guideline improved for the selection of antimicrobial agents (from 34.5% to 61.0%, P  < 0.0005), dosage (from 15.2% to 36.5%, P  < 0.0005) and duration (from 13.2% to 31.0%, P  < 0.0005). In total, 79.7% of patients (247/310) had samples sent for microbiological analysis. Overall, 92.3% of patients improved on Day 3 (286/310). The proportion of patients receiving ceftriaxone was significantly reduced after the AMS ward rounds from 51.3% to 14.2% ( P  < 0.0005)., Conclusions: AMS measures can improve the quality of antimicrobial use in LMICs. However, long-term engagement is necessary to make AMS programmes in LMICs sustainable., (© The Author(s) 2022. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)

The integration of smartphones and microfluidics is nowadays the best possible route to achieve effective point-of-need testing (PONT), a concept increasingly demanded in the fields of human health, agriculture, food safety, and environmental monitoring. Nevertheless, efforts are still required to integrally seize all the advantages of smartphones, as well as to share the developments in easily adoptable formats. For this purpose, here we present the free platform appuente that was designed for the easy integration of microfluidic chips, smartphones, and the cloud. It includes a mobile app for end users, which provides chip identification and tracking, guidance and control, processing, smart-imaging, result reporting and cloud and Internet of Things (IoT) integration. The platform also includes a web app for PONT developers, to easily customize their mobile apps and manage the data of administered tests. Three application examples were used to validate appuente: a dummy grayscale detector that mimics quantitative colorimetric tests, a root elongation assay for pesticide toxicity assessment, and a lateral flow immunoassay for leptospirosis detection. The platform openly offers fast prototyping of smartphone apps to the wide community of lab-on-a-chip developers, and also serves as a friendly framework for new techniques, IoT integration and further capabilities. Exploiting these advantages will certainly help to enlarge the use of PONT with real-time connectivity in the near future., (© 2022. The Author(s).)

The phylogenetic tree of the Staphylococcus aureus complex consists of several distinct clades and the majority of human and veterinary S. aureus isolates form one large clade. In addition, two divergent clades have recently been described as separate species. One was named Staphylococcus argenteus , due to the lack of the "golden" pigment staphyloxanthin. The second one is S. schweitzeri , found in humans and animals from Central and West Africa. In late 2021, two additional species, S. roterodami and S. singaporensis , have been described from clinical samples from Southeast Asia. In the present study, isolates and their genome sequences from wild Straw-coloured fruit bats ( Eidolon helvum ) and a Diamond firetail ( Stagonopleura guttata , an estrildid finch) kept in a German aviary are described. The isolates possessed staphyloxanthin genes and were closer related to S. argenteus and S. schweitzeri than to S. aureus . Phylogenetic analysis revealed that they were nearly identical to both, S. roterodami and S. singaporensis . We propose considering the study isolates, the recently described S. roterodami and S. singaporensis as well as some Chinese strains with MLST profiles stored in the PubMLST database as different clonal complexes within one new species. According to the principle of priority we propose it should be named S. roterodami . This species is more widespread than previously believed, being observed in West Africa, Southeast Asia and Southern China. It has a zoonotic connection to bats and has been shown to be capable of causing skin and soft tissue infections in humans. It is positive for staphyloxanthin, and it could be mis-identified as S. aureus (or S. argenteus ) using routine procedures. However, it can be identified based on distinct MLST alleles, and " S. aureus " sequence types ST2470, ST3135, ST3952, ST3960, ST3961, ST3963, ST3965, ST3980, ST4014, ST4075, ST4076, ST4185, ST4326, ST4569, ST6105, ST6106, ST6107, ST6108, ST6109, ST6999 and ST7342 belong to this species., Competing Interests: DG is employed by a company, Illumina, but he performed experiments for this study before commencing this employment. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Monecke, Schaumburg, Shittu, Schwarz, Mühldorfer, Brandt, Braun, Collatz, Diezel, Gawlik, Hanke, Hotzel, Müller, Reinicke, Feßler and Ehricht.)

Burkholderia cepacia complex (Bcc) in airways of patients with cystic fibrosis (CF) is associated with an increased morbidity and mortality. A huge range of intrinsic antimicrobial resistances challenges the treatment of Bcc infections. The aim was to assess the susceptibility of Bcc to ceftazidime/avibactam and standard drugs for the treatment for CF patients and to determine the respective genomic determinants of resistance. Bcc isolates ( n  = 64) from a prospective multicenter study of CF airway pathogens (2004-2020, Germany) were subjected to broth microdilution and minimal inhibitory concentrations were interpreted with European Committee on Antimicrobial Susceptibility Testing and Clinical & Laboratory Standards Institute breakpoints. A synergism between aztreonam and avibactam was tested using ceftazidime/avibactam disks with or without aztreonam. Plasmids and chromosomes of all isolates were screened for antimicrobial resistance genes. The highest susceptibility rate was detected for trimethoprim/sulfamethoxazole (83%), followed by ceftazidime/avibactam (78%), ceftazidime (53%), levofloxacin (39%) and meropenem (27%). The median inhibition zone diameters of ceftazidime-avibactam and ceftazidime/avibactam plus aztreonam were equal. This was in line with the absence of known class B metallo-β-lactamases in any of the isolates. The majority of isolates carried bla penA (98%) and bla ampC (86%). Trimethoprim/sulfamethoxazole and ceftazidime/avibactam showed high susceptibility rates. Aztreonam in combination with ceftazidime/avibactam had no synergistic effect in our Bcc isolates.

The Staphylococcus aureus -related complex is formed by the Staphylococcus aureus , Staphylococcus schweitzeri , Staphylococcus argenteus , Staphylococcus roterodami and Staphylococcus singaporensis . Within this complex, S. schweitzeri is the only species mainly found in African wildlife, but it is rarely detected as a colonizer in humans or as a contaminant of fomites. The few detections in humans are most likely spillover events after contact with wildlife. However, since S. schweitzeri can be misidentified as S. aureus using culture-based routine techniques, it is likely that S. schweitzeri is under-reported in humans. The low number of isolates in humans, though, is consistent with the fact that the pathogen has typical animal adaptation characteristics (e.g., growth kinetics, lack of immune evasion cluster and antimicrobial resistance); however, evidence from selected in vitro assays (e.g., host cell invasion, cell activation, cytotoxicity) indicate that S. schweitzeri might be as virulent as S. aureus . In this case, contact with animals colonized with S. schweitzeri could constitute a risk for zoonotic infections. With respect to antimicrobial resistance, all described isolates were found to be susceptible to all antibiotics tested, and so far no data on the development of spontaneous resistance or the acquisition of resistance genes such the mecA / mecC cassette are available. In summary, general knowledge about this pathogen, specifically on the potential threat it may incur to human and animal health, is still very poor. In this review article, we compile the present state of scientific research, and identify the knowledge gaps that need to be filled in order to reliably assess S. schweitzeri as an organism with global One Health implications.

We describe the identification of a methicillin-resistant, high-level mupirocin-resistant Staphylococcus argenteus . The isolate (1801221) was characterized as t6675-ST2250-SCC mec IVc, and whole-genome sequencing revealed that the isolate possessed two plasmids. One plasmid (34,870 bp), designated p1&#95;1801221 with rep23 , harboured the mupirocin resistance ( mupA ) gene. The second plasmid (20,644 bp), assigned as p2&#95;1801221 with rep5a and rep16 , carried the resistance determinants for penicillin ( blaZ ) and cadmium ( cadD ). Phylogenetic analysis revealed that the isolate clustered with the European ST2250 lineage. The overall high similarity of both plasmids in S. argenteus with published DNA sequences of Staphylococcus aureus plasmids strongly suggests an interspecies transfer. The pathogenic potential, community and nosocomial spread, and acquisition of antibiotic resistance gene determinants, including the mupA gene by S. argenteus , highlight its clinical significance and the need for its correct identification., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Shittu, Layer-Nicolaou, Strommenger, Nguyen, Bletz, Mellmann and Schaumburg.)

Background: Africa is challenged by the emergence of antimicrobial resistance (AMR). In order to improve patient management and to optimise approaches to curb the spread of antimicrobial resistance, we examined knowledge and perceptions of AMR and antibiotics prescription practices of HCW (healthcare workers) in Lambaréné, Gabon., Methods: We conducted a self-administered, questionnaire-based survey in HCW at the regional referral hospital, a medical research centre, and peripheral health care facilities. The proportions of correct responses to questions were determined and compared between physicians and nurses using Fisher's Exact test., Results: A total of 47 HCW took part in the survey. Of those, 64% (30/47) recognised antibiotic resistance as a major public health issue in Gabon, but only 14/47 (30%) recognised it as a problem in their health facility. Of note, 37/47 (79%) recognised excessive use of antibiotics without microbiological confirmation in case of infection, and buying antibiotics without a prescription, as possible cause of antimicrobial resistance. Some HCW (28%; 13/47) reported having prescribed antibiotics because the patients asked for them; and a total of 15/47 (32%) responded that antibiotics could help patients recover faster when added to malaria treatment. Compared to nurses, most of the physicians recognised that excessive use of antibiotics without microbiological confirmation of infection could contribute to AMR spread (18/19 (95%) vs 19/28 (68%); p = 0.028)., Conclusion: Most HCW recognised AMR as public health issue. However, a quarter of the participants did not know about the causes fostering the emergence of antimicrobial resistance. There is a need to perform regular HCW training in antimicrobial prescription, and to set up an antimicrobial stewardship program., (© 2022. The Author(s).)

Several methods to isolate monocytes from whole blood have been previously published, with different advantages and disadvantages. For the purpose of cytokine release assessment upon external stimulation, the use of monocyte preparations consisting of non-activated cells is prerequisite. Affinity-isolated monocyte preparations from peripheral blood mononuclear cells (PBMCs), obtained via positive or negative selection using magnetic beads, released pro-inflammatory cytokines such as TNF-α and IL-6 even without adding external stimuli, hindering any assessment of an effect of bacterial lipoproteins on cell stimulation. Hence, the cell preparation protocol was modified by adding a quiescence step on repellent surface culture plates, dampening any monocyte pre-activation. This protocol now provides a robust method to prepare silent yet fully activatable, pure monocyte populations for further use in stimulus-elicited activation experiments.

Vancomycin-resistant enterococci (VRE) pose a public health challenge worldwide. While VRE bloodstream infections (VREBI) increase in Germany and Europe, population-based molecular data are scarce. We aimed to analyze the molecular epidemiology, demographic aspects, and geographical distribution of VREBI in the German Federal State of North-Rhine-Westphalia (NRW), located in the German-Dutch-Belgian border area, representing over 20% of Germany's population. VREBI isolates were collected from hospitals across NRW between 2016 and 2019. Demographic data were gathered and anonymized upon sample collection. Multilocus sequence typing (MLST) and identification of glycopeptide resistance were carried out. Epidemiological analysis and geographical mapping were performed. Single VREBI isolates from 755 patients were analyzed. In total, 38.9% were female, and 80.0% were aged ≥ 60 years. The VREBI incidence per 100,000 inhabitants nearly tripled, from 0.52 (2016) to 1.48 (2019), particularly in male patients aged ≥ 50 years. The proportion of vanB reached 83% ( n = 202/243) in 2018, overtaking vanA as the predominant glycopeptide resistance determinant, detected in close relation with ST117 isolates. The proportion of MLST sequence type (ST) 117 peaked in 2018, at 78.2% ( n = 190/243). The major role of these emerging strains in invasive infections in central Europe requires novel strategies for their diagnosis, treatment, and prevention.

Background: Deficits in global oral health care are paramount, and complications of odontogenic infections constitute a considerable global health problem, particularly in low-income countries. A high mortality rate has been observed for patients who have been admitted with complicated odontogenic infections to our facilities in Tonkolili District, Sierra Leone, although exact data have not been published yet. Data regarding who in this region is at risk and why are lacking., Objective: The Dental Abscess Study (DELAY) aims to prospectively investigate morbidity and mortality from complicated dental abscesses and to analyze patients' characteristics and microbial findings to examine predisposing factors for poor outcomes. In particular, the incidence and the clinical and microbial characteristics of complicated odontogenic infections, as well as the sociodemographic data and comorbidities of affected patients, will be studied to develop improved management algorithms based on circumstance-specific factors., Methods: Patients who present with complicated dental infections requiring hospital admission in Masanga Hospital or Lion Heart Medical Centre will be consecutively selected for possible inclusion in the study (starting on September 4, 2021) over a study period of 1 year, and individual routine follow-ups will be conducted at least 3 months after discharge. The results of standardized questionnaires will be obtained, and clinical measurements as well as medical photos will be taken. Standard laboratory tests (eg, full blood count and HIV status tests) will be performed, and pus specimens will be examined. Local treatment guidelines will be adhered to, and data on medical and surgical treatment as well as data on outcomes will be collected. The study results will be reported according to the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) criteria. Routine follow-ups will take place at 1 and 3 months postdischarge., Results: The DELAY protocol was endorsed by the Masanga Medical Research Unit's Scientific Review Committee on June 16, 2021, and ethical approval was granted on July 5, 2021, by the Sierra Leone National Ethics Committee. The funding of the budgeted study costs was approved by Dental Health International Netherlands in August 2021. The projected start date of data collection was September 4, 2021, and the study period will most likely last for 1 year. As such, data collection is expected to be complete in November 2022., Conclusions: The aim of our prospective observational cohort study is to gain more knowledge about complicated odontogenic infections in Tonkolili District, Sierra Leone, to further improve treatment strategies., International Registered Report Identifier (irrid): DERR1-10.2196/33677., (©Hanna M J L Hazenberg, Jan Henk Dubbink, Issa Sesay, Tom Versteege, Hassan Bangura, Louise K Hoevenaars, Abdul M Falama, Heleen M Koudijs, Rosa Roemers, Emmanuel B Bache, Emil F Kelling, Frieder Schaumburg, Fred K L Spijkervet, Martin P Grobusch. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 13.12.2021.)

To evaluate potential pathomechanisms in the induction of infective endocarditis (IE), 34 Staphylococcus aureus ( S. aureus ) isolates, collected from patients with S. aureus endocarditis and from healthy individuals were investigated both in vitro and in vivo. S. aureus isolates were tested in vitro for their cytotoxicity, invasion and the association with platelets. Virulence factor expression profiles and cellular response were additionally investigated and tested for correlation with the ability of S. aureus to induce vegetations on the aortic valves in vivo . In an animal model of IE valvular conspicuity was assessed by in vivo magnetic resonance imaging at 9.4 T, histology and enrichment gene expression analysis. All S. aureus isolates tested in vivo caused a reliable infection and inflammation of the aortic valves, but could not be differentiated and categorized according to the measured in vitro virulence profiles and cytotoxicity. Results from in vitro assays did not correlate with the severity of IE. However, the isolates differed substantially in the activation and inhibition of pathways connected to the extracellular matrix and inflammatory response. Thus, comprehensive approaches of host-pathogen interactions and corresponding immune pathways are needed for the evaluation of the pathogenic capacity of bacteria. An improved understanding of the interaction between virulence factors and immune response in S. aureus infective endocarditis would offer novel possibilities for the development of therapeutic strategies and specific diagnostic imaging markers.

Objectives: Many laboratories do not perform antimicrobial susceptibility testing (AST) for all consecutive isolates of the same species from one patient. The objective of this study was to assess how often changes in antimicrobial susceptibility patterns (cASP) occur in such isolates., Methods: AST was performed for all isolates of defined species obtained from clinical routine (2015-2018) without restrictions for consecutive or sequential isolates of one patient. Occurrence of cASP and time between the first sampling date and first cASP were determined by combining antibiograms from all specimens and after stratification into species and specimens., Results: A total of 35 473 AST results were included (range 2-71 per case). Combining pathogens and specimens, 1991 cASP occurred in 1269/8502 (14.9%) of all cases after a median time until cASP of 5 days (range 0-364). Of these, 628/1991 (31.5%) occurred on the day of first sampling (predominantly due to phenotypic variants in the same specimen). Excluding isolates with differing AST pattern on the first day of sampling, the median time until cASP was 12 days (range 1-364). Stratification into species and specimen revealed a large variance of the median time until cASP (e.g. in Escherichia coli: 5 days; range 1-48 for blood cultures or 16 days; 1-364 for urine)., Discussion: Using routine microbiological data in a large tertiary hospital, cASP occurs occasionally. The time to perform subsequent AST to detect cASP depends on the species and type of specimen. Other studies are needed to evaluate whether ideal time intervals applicable beyond local settings can be defined., (Copyright © 2021 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)