Using (1,3)-β-D-glucan concentrations in serum to monitor the response of azole therapy in patients with eumycetoma caused by Madurella mycetomatis

INTRODUCTION

(1,3)-β-D-glucan is a panfungal biomarker secreted by many fungi, including Madurella mycetomatis, the main causative agent of eumycetoma. Previously we demonstrated that (1,3)-β-D-glucan was present in serum of patients with eumycetoma. However, the use of (1,3)-β-D-glucan to monitor treatment responses in patients with eumycetoma has not been evaluated.

MATERIALS AND METHODS

In this study, we measured (1,3)-β-D-glucan concentrations in serum with the WAKO (1,3)-β-D-glucan assay in 104 patients with eumycetoma treated with either 400 mg itraconazole daily, or 200 mg or 300 mg fosravuconazole weekly. Serial serum (1,3)-β-D-glucan concentrations were measured at seven different timepoints. Any correlation between initial and final (1,3)-β-D-glucan concentrations and clinical outcome was evaluated.

RESULTS

The concentration of (1,3)-β-D-glucan was obtained in a total of 654 serum samples. Before treatment, the average (1,3)-β-D-glucan concentration was 22.86 pg/mL. During the first 6 months of treatment, this concentration remained stable. (1,3)-β-D-glucan concentrations significantly dropped after surgery to 8.56 pg/mL. After treatment was stopped, there was clinical evidence of recurrence in 18 patients. Seven of these 18 patients had a (1,3)-β-D-glucan concentration above the 5.5 pg/mL cut-off value for positivity, while in the remaining 11 patients, (1,3)-β-D-glucan concentrations were below the cut-off value. This resulted in a sensitivity of 38.9% and specificity of 75.0%. A correlation between lesion size and (1,3)-β-D-glucan concentration was noted.

CONCLUSION

Although in general (1,3)-β-D-glucan concentrations can be measured in the serum of patients with eumycetoma during treatment, a sharp decrease in β-glucan concentration was only noted after surgery and not during or after antimicrobial treatment. (1,3)-β-D-glucan concentrations were not predictive for recurrence and seem to have no value in determining treatment response to azoles in patients with eumycetoma.

The combination of manogepix and itraconazole is synergistic and inhibits the growth of Madurella mycetomatis in vitro but not in vivo

Mycetoma is a neglected tropical disease commonly caused by the fungus Madurella mycetomatis. Standard treatment consists of extensive treatment with itraconazole in combination with surgical excision of the infected tissue, but has a low success rate. To improve treatment outcomes, novel treatment strategies are needed. Here, we determined the potential of manogepix, a novel antifungal agent that targets the GPI-anchor biosynthesis pathway by inhibition of the GWT1 enzyme. Manogepix was evaluated by determining the minimal inhibitory concentrations (MICs) according to the CLSI-based in vitro susceptibility assay for 22 M. mycetomatis strains and by in silico protein comparison of the target protein. The synergy between manogepix and itraconazole was determined using a checkerboard assay. The efficacy of clinically relevant dosages was assessed in an in vivo grain model in Galleria mellonella larvae. MICs for manogepix ranged from <0.008 to >8 mg/l and 16/22 M. mycetomatis strains had an MIC ≥4 mg/ml. Differences in MICs were not related to differences observed in the GWT1 protein sequence. For 70% of the tested isolates, synergism was found between manogepix and itraconazole in vitro. In vivo, enhanced survival was not observed upon admission of 8.6 mg/kg manogepix, nor in combination treatment with 5.7 mg/kg itraconazole. MICs of manogepix were high, but the in vitro antifungal activity of itraconazole was enhanced in combination therapy. However, no efficacy of manogepix was found in an in vivo grain model using clinically relevant dosages. Therefore, the therapeutic potential of manogepix in mycetoma caused by M. mycetomatis seems limited.

Perceptions of Rapid Antiretroviral Therapy Initiation Among Participants of The Netherlands Cohort Study on Acute HIV Infection

Starting antiretroviral therapy (ART) same-day, or as soon as possible after HIV diagnosis is advised in guidelines worldwide. Especially during acute HIV infection (AHI), rapid ART start may be more urgent because of a higher risk of transmission or symptoms of acute retroviral syndrome. During this phase, rapid ART start may have additional benefits for viral reservoir size and host immunity. We explored perceptions of rapid ART start among participants of The Netherlands Cohort Study on Acute HIV infection (NOVA study), who started ART rapidly after diagnosis of AHI. We conducted 20 in-depth qualitative interviews with NOVA study participants between October and December 2018. Data were analyzed thematically, using inductive and iterative coding techniques. Roughly half of the participants stated they felt well-informed about the importance of (rapid) ART. Starting ART rapidly was perceived positively by almost all participants, mostly because of the expected benefits on their health, and to prevent HIV transmission. Rapid ART start was seen as a way to cope with the diagnosis. However, a more negative perception was that rapid ART start confronted participants with their diagnosis, when they were still adjusting to a new situation. Our results show that among people diagnosed during AHI, rapid ART is well-accepted. These results should be encouraging to HIV care providers who encounter people with AHI in their clinical practice and to researchers who carry out cure-related studies, in which early ART is often included. The Clinical Trial Registration number is NCT05728996.

Integrated analysis of viral blips, residual viremia, and associated factors in people with HIV: Results from a retrospective cohort study

The etiology of viral blips is not yet fully elucidated. One of the hypotheses is that blips reflect variations in residual viremia (RV) near the detectability threshold. In this study, we evaluated whether RV is associated with viral blips and which factors are associated with RV. All treatment regimens in 2010-2020 consisting of two nucleos(-t)ide reverse transcriptase inhibitors and one anchor (integrase strand transfer inhibitor [INSTI], non-nucleoside reverse transcriptase inhibitor [NNRTI], or protease inhibitor [PI]) in people with HIV (PWH) were evaluated for RV (detectable viremia <50 cp/mL) and blips (isolated viral loads [VLs] 50-499 cp/mL between measurements <50 cp/mL). All medical records were reviewed and regimens in which a VL ≥ 50 cp/mL was deemed to result from non-adherence (based on the documented conclusion by the treating physician) were excluded. Factors associated with blips and RV were identified using generalized linear mixed models. In total, 24 518 VLs from 1658 PWH were analyzed. VLs were measured during INSTI- (n = 5119; 20.9%), PI- (n = 8935; 36.4%), and NNRTI-use (n = 10 464; 42.7%). VLs were categorized as blips in 1.4% (n = 332). The 24,186 non-blip VLs were RNAneg (no RV) (n = 15 326; 63.4%), 1-19 cp/mL (n = 6318; 26.1%), 20-49 cp/mL (n = 1620; 6.7%), or <50 cp/mL with an unknown RV level (n = 922; 3.8%). In 193/1658 PWH (11.6%), the RV level was RNAneg in all VLs assessed. RV 1-19 cp/mL and 20-49 cp/mL (vs. RNAneg ) were significantly associated with subsequent viral blips (respective odds ratio 2.66 and 4.90 [95% confidence intervals: 1.98-3.58 and 3.41-7.04]). Zenith VL and use of PIs (vs. INSTIs/NNRTIs) were associated with higher RV and blip odds. This large cohort study showed that blips were associated with higher preceding RV. Both the anchor type and factors previously linked to the latent viral reservoir were associated with RV, suggesting blips having a multifactorial origin.

Seasonality of antimicrobial use in Dutch food-producing animals

Due to globally increasing antimicrobial resistance (AMR), it is pivotal to understand factors contributing to antimicrobial use (AMU) to enable development and implementation of AMR-reducing interventions. Therefore, we explored seasonal variations of systemic AMU in food-producing animals in the Netherlands. Dutch surveillance data from January 2013 to December 2018 from cattle, pig, and broiler farms were used. AMU was expressed as the number of Defined Daily Dosages Animal per month (DDDA/animal-month) per farm by animal sector, antimicrobial line (first, second, and third), antimicrobial class, and farm type. Seasonality of AMU was analyzed using Generalized Additive Models (GAMs) with DDDA/animal-month as outcome variable, and year and month as independent variables. Year and month were modelled as smooth terms represented with penalized regression splines.Significant seasonality of AMU was found in the cattle and pig sectors, but not in broilers. Significant seasonality of AMU was found mainly for first-line antimicrobials. In the cattle sector, a significant increase during winter was found for the use of amphenicols (an increase of 23.8%) and long-acting macrolides (an increase of 3.4%). In the pig sector, seasonality of AMU was found for pleuromutilins (p < 0.001) with an increase of 20% in October-November. The seasonality of pleuromutilins was stronger in sows/piglets (an increase of 47%) than in fattening pigs (16% increase). Only in fattening pigs, the use of amphenicols showed a significant seasonality with an increase of 11% during winter (P < 0.001). AMU in cattle and pig sectors shows seasonal variations likely caused by seasonality of diseases. In broilers, no AMU seasonality was observed, possibly due to the controlled environment in Dutch farms. In the context of the one health concept, future studies are necessary to explore whether this seasonality is present in other populations and whether it has implications for antimicrobial resistance in humans through the food chain.

The efficacy and tolerability of latency-reversing agents in reactivating the HIV-1 reservoir in clinical studies: a systematic review

Introduction

Understanding the clinical potency of latency-reversing agents (LRAs) on the HIV-1 reservoir is useful to deploy future strategies. This systematic review evaluated the effects of LRAs in human intervention studies.

Methods

A literature search was performed using medical databases focusing on studies with adults living with HIV-1 receiving LRAs. Eligibility criteria required participants from prospective clinical studies, a studied compound hypothesised as LRA, and reactivation or tolerability assessments. Relevant demographical data, LRA reactivation capacity, reservoir size, and adverse events were extracted. A study quality assessment with analysis of bias was performed by RoB 2 and ROBINS-I tools. The primary endpoints were HIV-1 reservoir reactivation after LRA treatment quantified by cell-associated unspliced HIV-1 RNA, and LRA tolerability defined by adverse events. Secondary outcomes were reservoir size and the effect of LRAs on analytical treatment interruption (ATI) duration.

Results

After excluding duplicates, 5182 publications were screened. In total 45 publications fulfilled eligibility criteria including 26 intervention studies and 16 randomised trials. The risk of bias was evaluated as high. Chromatin modulators were the main investigated LRA class in 24 studies. Participants were mostly males (90.1%). Where reported, HIV-1 subtype B was most frequently observed. Reactivation after LRA treatment occurred in 78% of studies and was observed with nearly all chromatin modulators. When measured, reactivation mostly occurred within 24 h after treatment initiation. Combination LRA strategies have been infrequently studied and were without synergistic reactivation. Adverse events, where reported, were mostly low grade, yet occurred frequently. Seven studies had individuals who discontinued LRAs for related adverse events. The reservoir size was assessed by HIV-1 DNA in 80% of studies. A small decrease in reservoir was observed in three studies on immune checkpoint inhibitors and the histone deacetylase inhibitors romidepsin and chidamide. No clear effect of LRAs on ATI duration was observed.

Conclusion

This systematic review provides a summary of the reactivation of LRAs used in current clinical trials whilst highlighting the importance of pharmacovigilance. Highly heterogeneous study designs and underrepresentation of relevant patient groups are to be considered when interpreting these results. The observed reactivation did not lead to cure or a significant reduction in the size of the reservoir. Finding more effective LRAs by including well-designed studies are needed to define the required reactivation level to reduce the HIV-1 reservoir.

A Falciformispora senegalensis grain model in Galleria mellonella larvae

Eumycetoma is a subcutaneous implantation mycosis often found in the foot. One of the hallmarks of eumycetoma is the formation of grains. These grains are either black or white, and the consistency and morphology differs per causative agent. The two most common causative agents of black-grain eumycetoma are Madurella mycetomatis and Falciformispora senegalensis. Since grains cannot be formed in vitro, in vivo models are needed to study grain formation. Here, we used the invertebrate Galleria mellonella to establish an in vivo grain model for F. senegalensis. Three different F. senegalensis strains were selected, and four different inocula were used to infect G. mellonella larvae, ranging from 0.04 mg/larvae to 10 mg/larvae. Larval survival was monitored for 10 days. Grain formation was studied macroscopically and histologically. The efficacy of antifungal therapy was determined for itraconazole, amphotericin B, and terbinafine. A concentration of 10 mg F. senegalensis per larva was lethal for the majority of the larvae within 10 days. At this inoculum, grains were formed within 24 h after infection. The grains produced in the larvae resembled those formed in human patients. Amphotericin B given at 1 mg/kg 4 h, 28 h, and 52 h after infection prolonged larval survival. No enhanced survival was noted for itraconazole or terbinafine. In conclusion, we developed a F. senegalensis grain model in G. mellonella larvae in which grains were formed that were similar to those formed in patients. This model can be used to monitor grain formation over time and study antifungal efficacy.

Nitrofurantoin for the treatment of uncomplicated urinary tract infection in female patients: the impact of dosing regimen, age, and renal function on drug exposure

PURPOSE

The aim of this study is to determine nitrofurantoin exposure in female patients with different age and renal function with complaints of an uncomplicated UTI. Also the nitrofurantoin exposure in relation to the dosage regimen will be studied.

METHODS

Eight general practitioners (GP) participated in the study and included 38 patients with symptoms of an uncomplicated UTI, treated either with a dose of 50 mg q6h or 100 mg q12h, upon the discretion of the GP. Nitrofurantoin exposure was quantified in the patient's 24-h urine samples by UHPLC-UV and the area under the curve was calculated.

RESULTS

The 38 patients provided a range of 2-17 urine samples. The urine nitrofurantoin exposure was 1028 mg h/L for the patients receiving 50 mg q6h and 1036 mg h/L for those treated with 100 mg q12h (p = 0.97) and was not affected by age and eGFR (p = 0.64 and p = 0.34, respectively).

CONCLUSION

The data obtained do not support the discouragement of nitrofurantoin use in the elderly and in patients with impaired renal function. Since only a small number of patients were included, a larger study with more patients is warranted to evaluate nitrofurantoin exposure and adverse effects.

Baseline TGF-β correlates with protection after immunization with Plasmodium falciparum sporozoites in the Controlled Human Malaria Infection model

BACKGROUND

Here we assessed a possible relationship between baseline TGF-β concentrations and acquisition of sterile immunity after Plasmodium falciparum sporozoite immunization.

METHODS

TGF-β concentrations were determined in samples of 65 malaria-naive volunteers in 4 studies either prior to and after challenge infection, or prior to and after first immunizing infection under chemoprophylaxis with P. falciparum sporozoites.

RESULTS

High baseline TGF-β concentrations were associated with rapid acquisition of sterile protection (p=0.028).

CONCLUSION

Baseline TGF-β concentrations predict the efficiency of acquisition of sterile immunity following sporozoite immunisation and may represent a steady-state regulatory mechanism to keep in check immune systems with a low threshold for activation.

Antibiotic prescription patterns and non-clinical factors influencing antibiotic use by Ecuadorian veterinarians working on cattle and poultry farms: A cross-sectional study

Understanding antibiotic prescription patterns and non-clinical factors influencing antibiotic use is essential for implementing strategies to promote appropriate antibiotic use. There is, however, limited research exploring these issues with Ecuadorian veterinarians. Therefore, a questionnaire was developed and applied cross-sectionally to veterinarians (n = 173) from two professional organizations to explore the antibiotic prescription patterns and non-clinical factors (e.g., attitudes and perceptions) influencing antibiotic use, and to identify strategies to reduce antibiotic use. The response rate was 78.4%. Responses were compared between veterinarians working mainly on cattle and poultry farms using Mann-Whitney U tests. The most important attitudes, beliefs and perceptions towards antimicrobial resistance (AMR) and antibiotic use were identified with the Relative Importance Index (RII). Veterinarians showed high awareness of AMR and its implications for public health, as well as the necessity of reducing antibiotic use. However, some veterinarians appear to underestimate the potential contribution of veterinary antibiotic use on AMR in humans. Veterinarians self-reported high prescription (> 20%) of antibiotics for cattle and poultry that are critically important for human medicine, such as 3rd and 4th generation cephalosporins, polymyxins and quinolones. Further, antibiotic therapy was not tailored to disease type. Cattle and poultry veterinarians perceived similar barriers to increasing antibiotic stewardship including: poor biosecurity measures, animal confinement, low feed quality, farmers' behaviors (such as stopping antibiotic treatment, storing antibiotics on farms, buying antibiotics in veterinary supply stores), and sales agents' roles as non-professional prescribers of antibiotics. Overall, veterinarians were broadly supportive (>90%) of most strategies to promote appropriate antibiotic use. They saw more merit in improving biosecurity of farms and implementing educational programs for farmers and veterinarians. This study provides insight into the complexity of antibiotic use on Ecuadorian farms and the need for holistic strategies in a One Health context, to achieve antibiotic stewardship.

Wako β-D-glucan assay can be used to measure serum β-D-glucan in Sudanese patients to aid with diagnosis of eumycetoma caused by Madurella mycetomatis

BACKGROUND

Eumycetoma is a neglected tropical infection of the subcutaneous tissue commonly caused by the fungus Madurella mycetomatis. Previously, we demonstrated that β-D-glucan was present in the serum of eumycetoma patients.

OBJECTIVE

To compare the performance of the recently approved easy-to-use Wako β-D-glucan assay to that of the Fungitell assay in eumycetoma patients.

METHODS

Using sera obtained from 41 eumycetoma, 12 actinomycetoma and 29 healthy endemic controls, we measured the β-glucan serum concentrations using the Wako assay and compared the performance to that of the Fungitell assay.

RESULTS

With the Fungitell assay, median β-glucan serum concentrations of 208, 70 and 27 pg/ml were obtained for the 41 eumycetoma patients, the 12 actinomycetoma patients and the 29 healthy endemic controls, respectively. With the Wako assay these concentrations were 14.45, 11.57 and 2.5 pg/ml, respectively. We demonstrated that when using the optimized cut-off value (5.5 pg/ml) for the Wako assay, the Wako and Fungitell assays had comparable performance in terms of sensitivity and specificity.

CONCLUSION

The Wako assay is comparable to the Fungitell assay for measurement of serum β-glucan in mycetoma patients and hence can be used in combination with current diagnostic tools. However, this test should be used in combination with other tests to differentiate actinomycetoma from eumycetoma.

The BAF complex inhibitor pyrimethamine reverses HIV-1 latency in people with HIV-1 on antiretroviral therapy

Reactivation of the latent HIV-1 reservoir is a first step toward triggering reservoir decay. Here, we investigated the impact of the BAF complex inhibitor pyrimethamine on the reservoir of people living with HIV-1 (PLWH). Twenty-eight PLWH on suppressive antiretroviral therapy were randomized (1:1:1:1 ratio) to receive pyrimethamine, valproic acid, both, or no intervention for 14 days. The primary end point was change in cell-associated unspliced (CA US) HIV-1 RNA at days 0 and 14. We observed a rapid, modest, and significant increase in (CA US) HIV-1 RNA in response to pyrimethamine exposure, which persisted throughout treatment and follow-up. Valproic acid treatment alone did not increase (CA US) HIV-1 RNA or augment the effect of pyrimethamine. Pyrimethamine treatment did not result in a reduction in the size of the inducible reservoir. These data demonstrate that the licensed drug pyrimethamine can be repurposed as a BAF complex inhibitor to reverse HIV-1 latency in vivo in PLWH, substantiating its potential advancement in clinical studies.

Using a Madurella mycetomatis-specific PCR on grains obtained via non-invasive fine-needle aspirated material is more accurate than cytology

BACKGROUND

Eumycetoma is a chronic subcutaneous inflammatory fungal infection most often caused by the fungus Madurella mycetomatis. Using a species-specific PCR on DNA directly isolated from grains is currently the most reliable method for species identification. However, so far, PCR has been performed on grains obtained through deep-seated surgical biopsies, which are invasive procedures. Grains can also be obtained via ultrasound-guided fine-needle aspiration (US-FNA). Here we determined the diagnostic performance of species-specific PCRs performed on samples obtained through US-FNA.

METHODS

From 63 patients, US-FNA was performed to obtain eumycetoma grains; 34 patients also underwent a deep-seated biopsy. From the grains, DNA was isolated, and one pan-fungal and two M. mycetomatis-specific PCRs were performed. The sensitivity and specificity were determined.

RESULTS

Of the 63 patients who underwent US-FNA, 78% (49/63) had evidence of eumycetoma based on cytology and 93.7% (59/63) based on species-specific PCRs. In the 34 patients for whom surgical biopsies were performed as well, 31 patients had a positive PCR for M. mycetomatis when DNA was isolated from the deep-seated biopsy, and 30 had a positive PCR when DNA was obtained from the US-FNA material. This resulted in a 96.8% sensitivity, and 100% specificity with 97.1% diagnostic accuracy for PCR performed on US-FNA.

CONCLUSION

PCR performed on the US-FNA material has a similar sensitivity and specificity as PCR performed on deep-seated biopsies. Therefore, when using PCR, a deep-seated biopsy may not be necessary to obtain grains.

Exposure and virologic outcomes of dolutegravir combined with ritonavir boosted darunavir in treatment-naïve individuals enrolled in the Netherlands Cohort Study on Acute HIV infection (NOVA)

To the authors' knowledge, there is currently no literature or guidance recommendation regarding whether the dose of dolutegravir (DTG) should be increased when co-administered with darunavir/ritonavir (DRV/r) in patients with acute human immunodeficiency virus infection (AHI). This study assessed the pharmacokinetics (PK) of twice-daily (BID) DTG and once-daily (QD) DRV/r, and compared this with DTG QD without DRV/r in patients with AHI. Forty-six participants initiated antiretroviral therapy within <24 h of enrolment: DTG 50 mg BID, DRV/r 800/100 mg QD, and two nucleoside reverse transcriptase inhibitors (NRTIs) for 4 weeks (Phase I); and DTG 50 mg QD with two NRTIs thereafter (Phase II: reference). Total DTG trough concentration (C_trough) and area under the concentration-time profile of 0-24 h (AUC_0-24h) were predicted using a population PK model. DTG glucuronidation metabolic ratio (MR) and DTG free fraction were determined and compared per treatment phase using geometric mean ratio (GMR) and 90% confidence interval (CI). Participants had a predicted geometric mean steady-state DTG C_trough of 2.83 [coefficient of variation (CV%) 30.3%] mg/L (Phase I) and 1.28 (CV% 52.4%) mg/L (Phase II), with GMR of 2.20 (90% CI 1.90-2.55). Total exposure during DTG BID increased but did not double [AUC_0-24h GMR 1.65 (90% CI 1.50-1.81) h.mg/L]. DTG glucuronidation MR increased by approximately 29% during Phase I. DTG C_trough was above in-vivo EC₉₀ (0.32 mg/L) during both phases, except in one participant during Phase I. At Week 8, 84% of participants had viral loads ≤40 copies/mL. The drug-drug interaction between DTG (BID) and DRV/r (QD) was due to induced glucuronidation, and is not clinically relevant in patients with AHI.

Comparing the performance of the common used eumycetoma diagnostic tests

OBJECTIVES

Mycetoma is a neglected tropical implantation disease caused by 70 different infectious agents. Identifying the causative organism to the species level is essential for appropriate patient management. Ultrasound, histopathology, culture and two species-specific PCRs are most the commonly used methods for species identification in endemic regions. The aim of this study was to compare the diagnostic performance of these commonly used assays using sequencing of barcoding genes as the gold standard.

METHODS

This descriptive cross-sectional study was conducted at the Mycetoma Research Centre, University of Khartoum, Sudan. It included 222 patients suspected of fungal mycetoma caused by Madurella mycetomatis.

RESULTS

154 (69.3%) were correctly identified by ultrasound, histology, culture and both species-specific PCRs. In 60 patients, at least one of the diagnostic tests failed to identify M. mycetomatis. Five patients had no evidence of eumycetoma, and for three, only the ultrasound was indicative of mycetoma. The two species-specific PCRs were the most sensitive and specific methods, followed by culture and histology. Ultrasound was the least specific as it only allowed differentiation between actinomycetoma and eumycetoma. The time to result was 9.38 minutes for ultrasound, 3.76 hours for PCR, 8.5 days for histopathology and 21 days for grain culturing.

CONCLUSION

Currently, PCR directly on DNA isolated from grains is the most rapid and reliable diagnostic tool to identify M. mycetomatis eumycetoma.

Microcalorimetry: A Novel Application to Measure In Vitro Phage Susceptibility of Staphylococcus aureus in Human Serum

Infections involving antibiotic resistant Staphylococcus aureus (S. aureus) represent a major challenge to successful treatment. Further, although bacteriophages (phages) could be an alternative to antibiotics, there exists a lack of correlation in phage susceptibility results between conventional in vitro and in vivo assays. This discrepancy may hinder the potential implementation of bacteriophage therapy. In this study, the susceptibility of twelve S. aureus strains to three commercial phage cocktails and two single phages was assessed. These S. aureus strains (including ten clinical isolates, five of which were methicillin-resistant) were compared using four assays: the spot test, efficiency of plating (EOP), the optical density assay (all in culture media) and microcalorimetry in human serum. In the spot test, EOP and optical density assay, all cocktails and single phages lysed both methicillin susceptible and methicillin resistant S. aureus strains. However, there was an absence of phage-mediated lysis in high concentrations of human serum as measured using microcalorimetry. As this microcalorimetry-based assay more closely resembles in vivo conditions, we propose that microcalorimetry could be included as a useful addition to conventional assays, thereby facilitating more accurate predictions of the in vivo susceptibility of S. aureus to phages during phage selection for therapeutic purposes.

The 2000HIV study: Design, multi-omics methods and participant characteristics

Background

Even during long-term combination antiretroviral therapy (cART), people living with HIV (PLHIV) have a dysregulated immune system, characterized by persistent immune activation, accelerated immune ageing and increased risk of non-AIDS comorbidities. A multi-omics approach is applied to a large cohort of PLHIV to understand pathways underlying these dysregulations in order to identify new biomarkers and novel genetically validated therapeutic drugs targets.

Methods

The 2000HIV study is a prospective longitudinal cohort study of PLHIV on cART. In addition, untreated HIV spontaneous controllers were recruited. In-depth multi-omics characterization will be performed, including genomics, epigenomics, transcriptomics, proteomics, metabolomics and metagenomics, functional immunological assays and extensive immunophenotyping. Furthermore, the latent viral reservoir will be assessed through cell associated HIV-1 RNA and DNA, and full-length individual proviral sequencing on a subset. Clinical measurements include an ECG, carotid intima-media thickness and plaque measurement, hepatic steatosis and fibrosis measurement as well as psychological symptoms and recreational drug questionnaires. Additionally, considering the developing pandemic, COVID-19 history and vaccination was recorded. Participants return for a two-year follow-up visit. The 2000HIV study consists of a discovery and validation cohort collected at separate sites to immediately validate any finding in an independent cohort.

Results

Overall, 1895 PLHIV from four sites were included for analysis, 1559 in the discovery and 336 in the validation cohort. The study population was representative of a Western European HIV population, including 288 (15.2%) cis-women, 463 (24.4%) non-whites, and 1360 (71.8%) MSM (Men who have Sex with Men). Extreme phenotypes included 114 spontaneous controllers, 81 rapid progressors and 162 immunological non-responders. According to the Framingham score 321 (16.9%) had a cardiovascular risk of >20% in the next 10 years. COVID-19 infection was documented in 234 (12.3%) participants and 474 (25.0%) individuals had received a COVID-19 vaccine.

Conclusion

The 2000HIV study established a cohort of 1895 PLHIV that employs multi-omics to discover new biological pathways and biomarkers to unravel non-AIDS comorbidities, extreme phenotypes and the latent viral reservoir that impact the health of PLHIV. The ultimate goal is to contribute to a more personalized approach to the best standard of care and a potential cure for PLHIV.

Epidemiological cut-off values for itraconazole and ravuconazole for Madurella mycetomatis, the most common causative agent of mycetoma

BACKGROUND

Eumycetoma is a neglected tropical disease. It is a chronic inflammatory subcutaneous infection characterised by painless swellings which produce grains. It is currently treated with a combination of itraconazole and surgery. In an ongoing clinical study, the efficacy of fosravuconazole, the prodrug of ravuconazole, is being investigated. For both itraconazole and ravuconazole, no clinical breakpoints or epidemiological cut-off values (ECV) to guide treatment are currently available.

OBJECTIVE

To determine tentative ECVs for itraconazole and ravuconazole in Madurella mycetomatis, the main causative agent of eumycetoma.

MATERIALS AND METHODS

Minimal inhibitory concentrations (MICs) for itraconazole and ravuconazole were determined in 131 genetically diverse clinical M. mycetomatis isolates with the modified CLSI M38 broth microdilution method. The MIC distributions were established and used to determine ECVs with the ECOFFinder software. CYP51A sequences were sequenced to determine whether mutations occurred in this azole target gene, and comparisons were made between the different CYP51A variants and the MIC distributions.

RESULTS

The MICs ranged from 0.008 to 1 mg/L for itraconazole and from 0.002 to 0.125 mg/L for ravuconazole. The M. mycetomatis ECV for itraconazole was 1 mg/L and for ravuconazole 0.064 mg/L. In the wild-type population, two CYP51A variants were found for M. mycetomatis, which differed in one amino acid at position 499 (S499G). The MIC distributions for itraconazole and ravuconazole were similar between the two variants. No mutations linked to decreased susceptibility were found.

CONCLUSION

The proposed M. mycetomatis ECV for itraconazole is 1 mg/L and for ravuconazole 0.064 mg/L.

Development and validation of a resazurin assay for in vitro susceptibility testing of Actinomadura madurae: a common causative agent of actinomycetoma

OBJECTIVES

Actinomycetoma is a chronic granulomatous disease affecting skin, subcutaneous tissue, fascia, muscle and bones. With increasing resistance against commonly used treatment regimens, susceptibility testing is urgently needed.

METHODS

We developed an in vitro susceptibility assay for Actinomadura madurae, one of the common causative agents of actinomycetoma, employing resazurin for endpoint reading. Using this assay, reproducible MICs were determined for the most commonly used antibacterial agents for actinomycetoma treatment. The tested antibacterial agents included trimethoprim/sulfamethoxazole, amikacin, streptomycin, amoxicillin, ceftriaxone, gentamicin, ciprofloxacin, doxycycline, imipenem, linezolid, penicillin G and rifampicin.

RESULTS

Following the clinical breakpoints as stated by CLSI, 100% of the tested strains were susceptible to trimethoprim/sulfamethoxazole (MIC 0.03/0.59-1/19 mg/L), amikacin (MIC 0.0078-0.25 mg/L), doxycycline (MIC <0.25-1 mg/L) and linezolid (MIC <0.25-2 mg/L), 90% to ciprofloxacin (MIC <0.25-2 mg/L), 80% to ceftriaxone (MIC <0.5 to >64 mg/L) and imipenem (MIC <0.25-32 mg/L) and only 20% to amoxicillin (MIC <0.5 to >64 mg/L) and rifampicin (MIC 0.5 to >32 mg/L).

CONCLUSIONS

Determinations of MICs by visual readings of colour changes versus spectrophotometric readings were comparable. This convenient visual reading has the advantage of feasible implementation in endemic settings.

S4.5c Using serum beta-glucan measurements and sequencing of the Madurella mycetomatis azole target gene to predict therapeutic outcome during azole treatment in human mycetoma

 

S4.5 Mycetoma Clinical Trial on fosravuconazole treatment in eumycetoma– Top Line Results, September 22, 2022, 10:30 AM - 12:00 PM

Objectives

Eumycetoma is a neglected tropical disease characterized by large subcutaneous swellings and the formation of grains and most commonly caused by Madurella mycetomatis. The currently recommended therapy is a combination of antifungal therapy with an azole and surgery. Itraconazole is the current recommended drug and fosravuconazole, the pro-drug of ravuconzole, is currently clinically investigated. At the moment, there are no epidemiological cut-off values (ECV) for M. mycetomatis for either of these drugs or rapid diagnostic tests which can predict the therapeutic outcome of these treatments. Therefore, in this study, we determined the ECV for these drugs and determined whether there was a correlation between minimal inhibitory concentration (MIC) and the DNA sequence of the azole target gene CYP51A. We also assessed beta-glucan concentrations in the serum of mycetoma patients during treatment to establish whether any of these values were predictive for therapeutic outcomes.

Methods

In order to determine the ECV for M. mycetomatis, MIC distributions for itraconazole and ravuconazole were determined in genetically diverse clinical M. mycetomatis isolates using the ECOFFinder software. CYP51A sequences were sequenced and comparisons were made between the different CYP51A variants and the MIC distributions. Beta-glucan concentrations were measured in serum with the WAKO beta-glucan assay. Time points analyzed were 0, 22, 85, 176, 267, 358, and 455 days after the start of treatment.

Results

For M. mycetomatis the MICs ranged from 0.008 to 1 mg/l for itraconazole and from 0.002 to 0.125 mg/l for ravuconazole. The M. mycetomatis ECV for itraconazole was 1 mg/l and for ravuconazole 0.064 mg/l. In the wild-type population, two CYP51A variants were found for M. mycetomatis, which differed in one amino acid at position 499. The MIC distributions for itraconazole and ravuconazole were similar between the two variants. No mutations linked to decreased susceptibility were found. Before the start of treatment, beta-glucan concentrations ranged from below the detection limit to 217.9 pg/ml. Of these patients, 61.2% had a beta-glucan concentration above 7 pg/ml, the recommended cut-off value for positivity by the manufacturer, 72.8% had a beta-glucan concentration above 5.5 pg/ml, the recommended cut-off value for M. mycetomatis. During the first months of azole treatment, the beta-glucan concentrations remained relatively stable. After surgery, a sharp decrease in beta-glucan concentration in serum was noted. At the end of the observation period, only 13 patients had a beta-glucan concentration above 7 pg/ml and 14 above 5.5 pg/ml. Of these patients, for only 3, there was clinical evidence of a recurrence. For the remaining 4 patients with clinical evidence of a recurrence, the beta-glucan concentration was below the cut-off value for positivity.

Conclusion

In conclusion, so far there was no link established with the initial in vitro susceptibility and failure or success of the treatment therapy. Beta-glucan levels, in general, remained high during azole treatment, and a sharp drop in beta-glucan concentration in serum was only noted after surgery. A positive beta-glucan concentration at the end of the treatment was not indicative of a recurrence.

S4.5d Comparing the diagnostic performance of the commonly used eumycetoma diagnostic tests using sequencing of the internally transcribed spacer region as the gold standard

S4.5 Mycetoma Clinical Trial on fosravuconazole treatment in eumycetoma– Top Line Results, September 22, 2022, 10:30 AM - 12:00 PM

 

Objectives

Mycetoma is a neglected tropical implantation disease caused by 70 different infectious agents. Identifying the causative organism to the species level is essential for appropriate patient management. Ultrasound, histopathology, culture, and two species-specific PCRs are most the commonly used methods for species identification in endemic regions. The aim of this study was to compare the diagnostic performance of these commonly used assays using sequencing of barcoding genes as the gold standard.

Methods

This descriptive cross-sectional study was conducted at the Mycetoma Research Centre, University of Khartoum, Sudan. It included 222 patients suspected of fungal mycetoma caused by Madurella mycetomatis.

Results

In total 154 (69.3%) were correctly identified by ultrasound, histology, culture, and both species-specific PCRs. In 60 patients, at least one of the diagnostic tests failed to identify M. mycetomatis. A total of five patients had no evidence of eumycetoma, and for three, only the ultrasound was indicative of mycetoma. The two species-specific PCRs were the most sensitive and specific methods, followed by culture and histology. Ultrasound was the least specific as it only allowed differentiation between actinomycetoma and eumycetoma. The time to result was 9.38 minutes for ultrasound, 3.76 h for PCR, 8.5 days for histopathology, and 21 days for grain culturing.

Conclusion

Currently, PCR directly on DNA isolated from grains is the most rapid and reliable diagnostic tool to identify M. mycetomatis eumycetoma.

P445 Clinical evaluation of the performance of the most commonly used eumycetoma diagnostic tests using sequencing of the internally transcribed spacer region as the golden standard

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PM

 

Objective

Mycetoma is a neglected tropical skin disease, caused by 70 different causative agents. For most of the causative agents, molecular identification is the only reliable method to identify the species level. In practice, ultrasound, histopathology, culturing, and species-specific PCRs are most commonly used for species identification. However, the performance of these different tests was not validated using molecular identification by sequencing barcoding genes.

Methods

In this study, we validated the performance of the most commonly used diagnostic tools including culture, histopathology, Ultrasound and two species-specific PCR for Madurella mycetomatis on 222 patients suspected of fungal mycetoma by M. mycetomatis; the sensitivity, specificity, and accuracy of each method was calculated.

Results

From the 222 patients, 154 (69.3%) were correctly identified by ultrasound, histology, culture, and both species-specific PCRs. For five patients all tests were negative and for three only the ultrasound was indicative of mycetoma. For the other 60 patients, at least one of the assays was negative for M. mycetomatis. The two species-specific PCRs were the most sensitive and specific, followed by culture and histology. Ultrasound was the least specific as it only allows to differentiate between actinomycetoma and eumycetoma. However, with ultrasound, an identification could be obtained in 9.38 min. PCR took 3.76 h, histology 8.5 days, and culturing 21 days.

Conclusion

We concluded that PCR directly on DNA isolated from grains is the most rapid and reliable diagnostic tool to identify M. mycetomatis from eumycetoma grains to use species-specific PCRs. In order to shorten the time to identification of other causative agents, the focus should be on developing more molecular assays for those species.

Adherence to and usefulness of the national treatment guideline for urinary tract infections (UTI) in a risk area

Background

To optimize antibiotic treatment and decrease antibiotic resistance, national treatment guidelines are available for urinary tract infections (UTIs) in general practice. The usefulness of these guidelines in risk areas for antimicrobial resistance such as cross border regions or areas with dense agriculture, is unknown.

Methods

Midstream urine samples from women with symptoms of acute UTI visiting general practitioners (GPs) in the Westland area, a dense agriculture area, were microbiologically analysed, and patient characteristics, symptoms, previous and present antibiotic treatment were collected. The National Nivel data were used as reference for antibiotic resistance.

Results

Of 310 women with symptoms of uncomplicated UTI, 247 (80%) had a culture proven E. coli UTI. Empirical antibiotic therapy was prescribed to 148 patients (48%) in total; in 7% of women with a negative and 52% with a positive urine culture. Having more than one symptom was associated with the prescription of antibiotics; travel history or previous antibiotic use for UTI were not. The isolated uropathogens were susceptible to the empiric antibiotic therapy in 98% of patients. Resistance to co-amoxiclav was higher (22%) than reported in the national data of 2004 (12%), 2009 (13%) and 2014 (9%), as was the prevalence of extended spectrum β-lactamase (ESBL): 3.4% in our study versus 0.1%, 1% and 2.2% in the national data respectively.

Conclusion

The presence of environmental and socio-demographic risk factors for antibiotic resistance did not influence the empiric choice nor susceptibility for antibiotics advised by the national guidelines in women with uncomplicated UTI.

Isothermal microcalorimetry versus checkerboard assay to evaluate in vitro synergism of meropenem-amikacin and meropenem-colistin combinations against multidrug-resistant Gram-negative pathogens

OBJECTIVES

To evaluate the activity of meropenem-amikacin and meropenem-colistin combinations with checkerboard broth microdilution (CKBM) compared to isothermal microcalorimetry (ITMC) assays against a multicentric collection of multidrug-resistant Gram-negative (MDR-GN) clinical isolates, to compare the Fractional inhibitory concentration index (FICI) and time to results of CKBM and ITMC assays.

METHODS

A collection of 333 MDR-GNs showing reduced susceptibility to meropenem (121 Klebsiella pneumoniae, 14 Escherichia coli, 130 Pseudomonas aeruginosa and 68 Acinetobacter baumannii) isolated from different centres (Florence, Madrid, Rotterdam, and Stockholm) was included in the study. The antimicrobial activity of selected combinations was evaluated with CKBM and ITMC. FICI results were interpreted as synergistic/additive and indifferent for values ≤0.5/0.5<x≤1 and >1, respectively. WGS data in a subset of strains was used to evaluate their clonality.

RESULTS

A total of 254 and 286 strains were tested with meropenem-colistin and meropenem-amikacin combinations with ITMC and CKBM, respectively. Synergism/additive effects were observed with 46 strains (20 K. pneumoniae, 4 E. coli, 22 P. aeruginosa) and 20 strains (3 K. pneumoniae, 11 P. aeruginosa and 6 A. baumannii) with meropenem-amikacin and meropenem-colistin combination, respectively, with CKBM. ITMC showed a good concordance with CKBM with 89.5% and 92.2% of cases interpreted within the same FICI category for meropenem-amikacin and meropenem-colistin combinations, respectively. Most of the synergism/additivity effects were detected within 6 hours by ITMC.

CONCLUSIONS

ITMC showed a very good concordance with CKBM against a large collection of MDR-GN and could be implemented for the rapid evaluation of in vitro activity of antimicrobial combinations.

Madurella mycetomatis grains within a eumycetoma lesion are clonal

Eumycetoma is a neglected tropical infection of the subcutaneous tissue, characterized by tumor-like lesions and most commonly caused by the fungus Madurella mycetomatis. In the tissue, M. mycetomatis organizes itself in grains, and within a single lesion, thousands of grains can be present. The current hypothesis is that all these grains originate from a single causative agent, however, this hypothesis was never proven. Here, we used our recently developed MmySTR assay, a highly discriminative typing method, to determine the genotypes of multiple grains within a single lesion. Multiple grains from surgical lesions obtained from 11 patients were isolated and genotyped using the MmySTR panel. Within a single lesion, all tested grains shared the same genotype. Only in one single grain from one patient, a difference of one repeat unit in one MmySTR marker was noted relative to the other grains from that patient. We conclude that within these lesions the grains originate from a single clone and that the inherent unstable nature of the microsatellite markers may lead to small genotypic differences.

Ultrasound-guided Fine Needle Aspiration Cytology significantly improved mycetoma diagnosis

Background

Ultrasound (US)‐guided fine‐needle aspiration cytology (US‐FNAC) has improved the diagnosis of many malignancies, infections and other diseases as it is safe, simple, quick and accurate. In mycetoma, it is assumed that this technique may have a better diagnostic yield than the conventional FNAC as it can accurately identify the optimal site for the aspiration.

Objective

To compare the diagnostic yield of conventional FNAC with US‐FNAC.

Methods

This descriptive cross‐sectional hospital‐based study included 80 patients with clinically suspected mycetoma.

Results

Of the 80 patients included, 35 proved to have actinomycetoma, and 37 had eumycetoma based on surgical biopsies, histopathological examination and the culture of grains. Eight patients appeared to have no mycetoma. For actinomycetoma diagnosis, the US‐guided FNAC improved sensitivity to 97% and negative predictive value (NPV) to 83% compared to the conventional FNAC, which had 63% sensitivity; and NPV of 28%. No improvement was found for specificity. For eumycetoma, the conventional FNAC had 86.5% sensitivity, 100% specificity, 100% PPV and 37.5% NPV. The US‐FNAC for the diagnosis of eumycetoma had 100% sensitivity and specificity.

Conclusions and relevance

The obtained results showed that US‐FNAC is better than the conventional FNAC with lower false‐negative results. It can accurately distinguish between the two types of mycetoma, allowing rapid initiation of proper treatment. The technique can be used in rural areas with low resources and for epidemiological surveys as a quick screening tool for patients suspected of mycetoma.

Using Targeted Liquid Chromatography-Tandem Mass Spectrometry to Rapidly Detect β-Lactam, Aminoglycoside, and Fluoroquinolone Resistance Mechanisms in Blood Cultures Growing E. coli or K. pneumoniae

New and rapid antimicrobial susceptibility/resistance testing methods are required for bacteria from positive blood cultures. In this study, a multiplex-targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed and validated for the detection of β-lactam, aminoglycoside, and fluoroquinolone resistance mechanisms in blood cultures growing Escherichia coli or Klebsiella pneumoniae complex. Selected targets were the β-lactamases SHV, TEM, OXA-1-like, CTX-M-1-like, CMY-2-like, chromosomal E. coli AmpC (cAmpC), OXA-48-like, NDM, VIM, and KPC; the aminoglycoside-modifying enzymes AAC(3)-Ia, AAC(3)-II, AAC(3)-IV, AAC(3)-VI, AAC(6′)-Ib, ANT(2′′)-I, and APH(3′)-VI; the 16S-RMTases ArmA, RmtB, RmtC, and RmtF; the quinolone resistance mechanisms QnrA, QnrB, AAC(6′)-Ib-cr; the wildtype quinolone resistance determining region of GyrA; and the E. coli porins OmpC and OmpF. The developed assay was evaluated using 100 prospectively collected positive blood cultures, and 148 negative blood culture samples spiked with isolates previously collected from blood cultures or isolates carrying less prevalent resistance mechanisms. The time to result was approximately 3 h. LC-MS/MS results were compared with whole-genome sequencing and antimicrobial susceptibility testing results. Overall, there was a high agreement between LC-MS/MS results and whole-genome sequencing results. In addition, the majority of susceptible and non-susceptible phenotypes were correctly predicted based on LC-MS/MS results. Exceptions were the predictions for ciprofloxacin and amoxicillin/clavulanic acid that matched with the phenotype in 85.9 and 63.7% of the isolates, respectively. Targeted LC-MS/MS based on parallel reaction monitoring can be applied for the rapid and accurate detection of various resistance mechanisms in blood cultures growing E. coli or K. pneumoniae complex.

Identifying novel drugs with new modes of action for neglected tropical fungal skin diseases (fungal skinNTDs) using an Open Source Drug discovery approach

INTRODUCTION

The three fungal skin neglected tropical diseases (NTD) mycetoma, chromoblastomycosis and sporotrichosis currently lack prioritization and support to establish drug discovery programs in search for novel treatment options. This has made the efforts to identify novel drugs for these skinNTDs fragmented.

AREAS COVERED

To help escalate the discovery of novel drugs to treat these fungal skinNTDs, the authors have prepared an overview of the compounds with activity against fungal skinNTDs by analyzing data from individual drug discovery studies including those performed on the Medicines for Malaria Venture (MMV) open access boxes.

EXPERT OPINION

The authors were unable to identify studies in which causative agents of all three skinNTDs were included, indicating that an integrated approach is currently lacking. From the currently available data, the azoles and iodoquinol were the only compounds with activity against causative agents from the three different fungal skinNTDs. Fungal melanin inhibition enhanced the activity of antifungal agents. For mycetoma, the fenarimols, aminothiazoles and benzimidazole carbamates are currently being investigated in the MycetOS initiative. To come to a more integrated approach to identify drugs active against all three fungal skinNTDs, compounds made in the MycetOS initiative could also be explored for chromoblastomycosis and sporotrichosis.

The development and implementation of a guideline-based clinical decision support system to improve empirical antibiotic prescribing

Background

To describe and evaluate a clinical decision support system (CDSS) for empirical antibiotic therapy using a systematic framework.

Methods

A reporting framework for behavior change intervention implementation was used, which includes several domains: development, evaluation and implementation. Within the development domain a description is given of the engagement of stakeholders, a rationale for how the CDSS may influence antibiotic prescribing and a detailed outline of how the system was developed. Within the evaluation domain a technical validation is performed and the interaction between potential users and the CDSS is analyzed. Within the domain of implementation a description is given on how the CDSS was tested in the real world and the strategies that were used for implementation and adoption of the CDSS.

Results

Development: a CDSS was developed, with the involvement of stakeholders, to assist empirical antibiotic prescribing by physicians. Evaluation: Technical problems were determined during the validation process and corrected in a new CDSS version. A usability study was performed to assess problems in the system-user interaction. Implementation: In 114 patients the antibiotic advice that was generated by the CDSS was followed. For 54 patients the recommendations were not adhered to.

Conclusions

This study describes the development and validation of a CDSS for empirical antibiotic therapy and shows the usefulness of the systematic framework for reporting CDSS interventions. In addition it shows that CDSS recommendations are not always adhered to which is associated with incorrect use of the system.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-022-01860-3.

Eumycetoma Causative Agents are Inhibited in vitro by Luliconazole, Lanoconazole and Ravuconazole

Introduction

Eumycetoma is a subcutaneous mutilating disease that can be caused by many different fungi. Current treatment consists of prolonged itraconazole administration in combination with surgery. In many centres, due to their slow growth rate, the treatment for eumycetoma is often started before the causative agent is identified. This harbours the risk that the causative fungus is not susceptible to the given empirical therapy. In the open‐source drug program MycetOS, ravuconazole and luliconazole were promising antifungal agents that were able to inhibit the growth of Madurella mycetomatis, the most common causative agent of mycetoma. However, it is currently not known whether these drugs inhibit the growth of other eumycetoma causative agents.

Materials and methods

Here, we determined the in vitro activity of luliconazole, lanoconazole and ravuconazole against commonly encountered eumycetoma causative agents. MICs were determined for lanoconazole, luliconazole and ravuconazole against 37 fungal isolates which included Madurella species, Falciformispora senegalensis, Medicopsis romeroi and Trematosphaeria grisea and compared to those of itraconazole.

Results

Ravuconazole, luliconazole and lanoconazole showed high activity against all eumycetoma causative agents tested with median minimal inhibitory concentrations (MICs) ranging from 0.008–2 µg/ml, 0.001–0.064 µg/ml and 0.001–0.064 µg/ml, respectively. Even Ma. fahalii and Me. romeroi, which are not inhibited in growth by itraconazole at a concentration of 4 µg/ml, were inhibited by these azoles.

Conclusion

The commonly encountered eumycetoma causative agents are inhibited by lanoconazole, luliconazole and ravuconazole. These drugs are promising candidates for further evaluation as potential treatment for eumycetoma.

Predictive performance of comorbidity for 30-day and 1-year mortality in patients with bloodstream infection visiting the emergency department: a retrospective cohort study

OBJECTIVES

To investigate whether the Charlson Comorbidity Index (CCI) predicted short-term and long-term mortality in patients with a bloodstream infection visiting the emergency department (ED) and compare it to the often-validated National Early Warning Score (NEWS).

DESIGN

A retrospective cohort study.

SETTING

A tertiary hospital in the Netherlands.

PARTICIPANTS

Adult patients attending the ED with a blood culture-proven infection between 2012 and 2017 were included. We collected the comorbidities from the CCI and the vital signs from the NEWS.

MAIN OUTCOMES

Short-term mortality (30-day) and long-term mortality (1 year). We assessed the predictive performance by discrimination, expressed as the area under the curve (AUC).

RESULTS

We included 1039 patients with a blood culture-proven infection. Mortality was 10.4% within 30 days and 27.8% within 1 year. On average patients had two comorbidities (ranging from 0 to 6). Highly prevalent comorbidities were malignancy (30.2%) and diabetes mellitus (20.5%). The predictive performance of the CCI was highest for 1-year mortality (AUC 0.696 (95%CI) (0.660 to 0.732)) and better compared with the NEWS (AUC (95% CI) 0.594 (0.555 to 0.632)). For prediction of 30-day mortality, the NEWS was superior (AUC (95% CI) 0.706 (0.656 to 0.756)) to the comorbidities of the CCI (AUC (95% CI) 0.568 (0.507 to 0.628)).

CONCLUSIONS

We found that presenting comorbidity (ie, the CCI) is most useful to prognosticate long-term outcome in patients with bloodstream infection in the ED. Short-term mortality is more accurately predicted by deviating vital signs (ie, the NEWS).

Liquid Chromatography-Tandem Mass Spectrometry Analysis Demonstrates a Decrease in Porins and Increase in CMY-2 β-Lactamases in Escherichia coli Exposed to Increasing Concentrations of Meropenem

While Extended-Spectrum β-Lactamases (ESBL) and AmpC β-lactamases barely degrade carbapenem antibiotics, they are able to bind carbapenems and prevent them from interacting with penicillin-binding proteins, thereby inhibiting their activity. Further, it has been shown that Enterobacterales can become resistant to carbapenems when high concentrations of ESBL and AmpC β-lactamases are present in the bacterial cell in combination with a decreased influx of antibiotics (due to a decrease in porins and outer-membrane permeability). In this study, a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed for the detection of the Escherichia coli porins OmpC and OmpF, its chromosomal AmpC β-lactamase, and the plasmid-mediated CMY-2 β-lactamase. BlaCMY–2–like positive E. coli isolates were cultured in the presence of increasing concentrations of meropenem, and resistant mutants were analyzed using the developed LC-MS/MS assay, Western blotting, and whole genome sequencing. In five strains that became meropenem resistant, a decrease in OmpC and/or OmpF (caused by premature stop codons or gene interruptions) was the first event toward meropenem resistance. In four of these strains, an additional increase in MICs was caused by an increase in CMY-2 production, and in one strain this was most likely caused by an increase in CTX-M-15 production. The LC-MS/MS assay developed proved to be suitable for the (semi-)quantitative analysis of CMY-2-like β-lactamases and porins within 4 h. Targeted LC-MS/MS could have additional clinical value in the early detection of non-carbapenemase-producing carbapenem-resistant E. coli.

Real time monitoring of Staphylococcus aureus biofilm sensitivity towards antibiotics with isothermal microcalorimetry

Biofilm-associated infections with Staphylococcus aureus are difficult to treat even after administration of antibiotics that according to the standard susceptibility assays are effective. Currently, the assays used in the clinical laboratories to determine the sensitivity of S. aureus towards antibiotics are not representing the behaviour of biofilm-associated S. aureus, since these assays are performed on planktonic bacteria. In research settings, microcalorimetry has been used for antibiotic susceptibility studies. Therefore, in this study we investigated if we can use isothermal microcalorimetry to monitor the response of biofilm towards antibiotic treatment in real-time. We developed a reproducible method to generate biofilm in an isothermal microcalorimeter setup. Using this system, the sensitivity of 5 methicillin-sensitive S. aureus (MSSA) and 5 methicillin-resistant S. aureus (MRSA) strains from different genetic lineages were determined towards: flucloxacillin, cefuroxime, cefotaxime, gentamicin, rifampicin, vancomycin, levofloxacin, clindamycin, erythromycin, linezolid, fusidic acid, co-trimoxazole, and doxycycline. In contrast to conventional assays, our calorimetry-based biofilm susceptibility assay showed that S. aureus biofilms, regardless MSSA or MRSA, can survive the exposure to the maximum serum concentration of all tested antibiotics. The only treatment with a single antibiotic showing a significant reduction in biofilm survival was rifampicin, yet in 20% of the strains, emerging antibiotic resistance was observed. Furthermore, the combination of rifampicin with flucloxacillin, vancomycin or levofloxacin was able to prevent S. aureus biofilm from becoming resistant to rifampicin. Isothermal microcalorimetry allows real-time monitoring of the sensitivity of S. aureus biofilms towards antibiotics in a fast and reliable way.

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log₁₀ increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence.

Screening the pandemic response box identified benzimidazole carbamates, Olorofim and ravuconazole as promising drug candidates for the treatment of eumycetoma

Eumycetoma is a chronic subcutaneous neglected tropical disease that can be caused by more than 40 different fungal causative agents. The most common causative agents produce black grains and belong to the fungal orders Sordariales and Pleosporales. The current antifungal agents used to treat eumycetoma are itraconazole or terbinafine, however, their cure rates are low. To find novel drugs for eumycetoma, we screened 400 diverse drug-like molecules from the Pandemic Response Box against common eumycetoma causative agents as part of the Open Source Mycetoma initiative (MycetOS). 26 compounds were able to inhibit the growth of Madurella mycetomatis, Madurella pseudomycetomatis and Madurella tropicana, 26 compounds inhibited Falciformispora senegalensis and seven inhibited growth of Medicopsis romeroi in vitro. Four compounds were able to inhibit the growth of all five species of fungi tested. They are the benzimidazole carbamates fenbendazole and carbendazim, the 8-aminoquinolone derivative tafenoquine and MMV1578570. Minimal inhibitory concentrations were then determined for the compounds active against M. mycetomatis. Compounds showing potent activity in vitro were further tested in vivo. Fenbendazole, MMV1782387, ravuconazole and olorofim were able to significantly prolong Galleria mellonella larvae survival and are promising candidates to explore in mycetoma treatment and to also serve as scaffolds for medicinal chemistry optimisation in the search for novel antifungals to treat eumycetoma.

OUP accepted manuscript

Eumycetoma is a neglected tropical disease, and Madurella mycetomatis, the most common causative agent of this disease forms black grains in hosts. Melanin was discovered to be one of the constituents in grains. Melanins are hydrophobic, macromolecular pigments formed by oxidative polymerisation of phenolic or indolic compounds. M. mycetomatis was previously known to produce DHN-melanin and pyomelanin in vitro. These melanin was also discovered to decrease M. mycetomatis’s susceptibility to antifungals itraconazole and ketoconazole in vitro. These findings, however, have not been confirmed in vivo. To discover the melanin biosynthesis pathways used by M. mycetomatis in vivo and to determine if inhibiting melanin production would increase M. mycetomatis's susceptibility to itraconazole, inhibitors targeting DHN-, DOPA- and pyomelanin were used. Treatment with DHN-melanin inhibitors tricyclazole, carpropamid, fenoxanil and DOPA-melanin inhibitor glyphosate in M. mycetomatis infected Galleria mellonella larvae resulted in presence of non-melanized grains. Our finding suggested that M. mycetomatis is able to produce DOPA-melanin in vivo. Inhibiting DHN-melanin with carpropamid in combination with the antifungal itraconazole also significantly increased larvae survival. Our results suggested that combination treatment of antifungals and melanin inhibitors can be an alternative treatment strategy that can be further explored. Since the common black-grain eumycetoma causing agents uses similar melanin biosynthesis pathways, this strategy may be applied to them and other eumycetoma causative agents.

The association of body temperature with antibiotic therapy and mortality in patients attending the emergency department with suspected infection

BACKGROUND AND IMPORTANCE

Previous studies found that septic patients with normothermia have higher mortality than patients with fever. We hypothesize that antibiotic therapy is less frequently initiated if infectious patients present with normothermia to the emergency department (ED).

OBJECTIVES

To examine the association of body temperature with the initiation of antibiotic therapy in patients attending the ED with suspected and proven infection. Additionally, the association of temperature with 30-day mortality was assessed.

DESIGN, SETTINGS AND PARTICIPANTS

We conducted a retrospective cohort study between 2012 and 2016 at a tertiary university hospital. Adult patients attending the ED with a blood culture taken (i.e. suspected infection) and a positive blood culture (i.e. proven bacteremia) were included.

EXPOSURE

Tympanic temperature at arrival was categorized as hypothermia (<36.1°C), normothermia (36.1-38.0°C) or hyperthermia (>38.0°C).

OUTCOME MEASURES AND ANALYSIS

Primary outcome was the initiation of antibiotic therapy. A secondary outcome was 30-day mortality. Multivariable logistic regression was used to control for covariates.

MAIN RESULTS

Of 5997 patients with a suspected infection, 45.8% had normothermia, 44.6% hyperthermia and 5.6% hypothermia. Patients with hyperthermia received more often antibiotic therapy (53.5%) compared to normothermic patients (27.6%, adjusted odds ratio [95% confidence interval], 2.59 [2.27-2.95]). Patients with hyperthermia had lower mortality (4.7%) than those with normothermia (7.4%, adjusted odds ratio [95% confidence interval], 0.50 [0.39-0.64]). Sensitivity analyses in patients with proven bacteremia (n = 934) showed similar results.

CONCLUSION

Normothermia in patients presenting with infection was associated with receiving less antibiotic therapy in the ED compared to presentations with hyperthermia. Moreover, normothermia was associated with a higher mortality risk than hyperthermia.

Cohort profile: the Netherlands Cohort Study on Acute HIV infection (NOVA), a prospective cohort study of people with acute or early HIV infection who immediately initiate HIV treatment

PURPOSE

Initiation of combination antiretroviral therapy (cART) during acute or early HIV-infection (AEHI) limits the size of the viral reservoir and preserves immune function. This renders individuals who started cART during AEHI promising participants in HIV-cure trials. Therefore, we established a multicentre prospective cohort study in the Netherlands that enrols people with AEHI. In anticipation of future cure trials, we will longitudinally investigate the properties of the viral reservoir size and HIV-specific immune responses among cohort participants.

PARTICIPANTS

Participants immediately initiate intensified cART: dolutegravir, emtricitabine/tenofovir and darunavir/ritonavir (DRV/r). After 4 weeks, once baseline resistance data are available, DRV/r is discontinued. Three study groups are assembled based on the preparedness of individuals to participate in the extensiveness of sampling. Participants accepting immediate treatment and follow-up but declining additional sampling are included in study group 1 ('standard') and routine diagnostic procedures are performed. Participants willing to undergo blood, leukapheresis and semen sampling are included in study group 2 ('less invasive'). In study group 3 ('extended'), additional tissue (gut-associated lymphoid tissue, peripheral lymph node) and cerebrospinal fluid sampling are performed.

FINDINGS TO DATE

Between 2015 and 2020, 140 individuals with AEHI have been enrolled at nine study sites. At enrolment, median age was 36 (IQR 28-47) years, and 134 (95.7%) participants were men. Distribution of Fiebig stages was as follows: Fiebig I, 3 (2.1%); II, 20 (14.3%); III, 7 (5.0%); IV, 49 (35.0%); V, 39 (27.9%); VI, 22 (15.7%). Median plasma HIV RNA was 5.9 (IQR 4.7-6.7) log10 copies/mL and CD4 count 510 (IQR 370-700) cells/mm3. Median time from cART initiation to viral suppression was 8.0 (IQR 4.0-16.0) weeks.

FUTURE PLANS

The Netherlands Cohort Study on Acute HIV infection remains open for participant enrolment and for additional sites to join the network. This cohort provides a unique nationwide platform for conducting future in-depth virological, immunological, host genetic and interventional studies investigating HIV-cure strategies.

Quality of life among people living with HIV in England and the Netherlands: a population-based study

Background

HIV is now considered a chronic condition, and people living with HIV, when treated, have a similar life expectancy as compared to the general population. Consequently, improving and ensuring a good health-related quality of life (HrQoL) among people living with HIV (people living with HIV) is increasingly important and has risen on the global agenda in recent years. A 'fourth 90' as 90% of people with viral load suppression have a good HrQoL should therefore be adopted alongside the other 90-90-90 targets. This study aims to report the progress on HrQoL as the 'fourth 90' and compare against the general population in the Netherlands and England.

Methods

In the Netherlands, individuals attending the HIV outpatient clinic of a tertiary hospital were asked to complete the EQ-5D-5L from June 2016 until December 2018. In England, individuals attending one of 73 HIV outpatient clinics were randomly sampled to complete the Positive Voices survey, which included the EQ-5D-5L, from January to September 2017. HrQoL scores were combined with demographic data and compared to general population data.

Findings

The EQ-5D-5L was filled-out by 895 people living with HIV in the NL and 4,137 in England. HrQoL_utility was 0·85 among Dutch and 0·83 among English people living with HIV. This equated to 98% and 94% of the general population HrQoL_utility in the Netherlands and England, respectively. Of the EQ-5D domains, anxiety/depression was mostly affected, with one-third in Dutch (35%) and almost half (47%) of English people living with HIV reporting symptoms. This was higher compared to their respective general populations (21% NL and 31% England).

Interpretation

Overall, HrQoL_utility for people living with HIV was high in both countries and highly comparable to the general populations Nevertheless, there should be an increased focus on anxiety and depression in the people living with HIV population The EQ-5D-5L proved an easy HrQoL measurement tool and identified areas for improvement by social and behavioural interventions.

Funding

The study received funding (unrestricted grants) from: Gilead sciences, ViiV Healthcare, MSD, and Jansen pharmaceuticals.

COVID outcome prediction in the emergency department (COPE): using retrospective Dutch hospital data to develop simple and valid models for predicting mortality and need for intensive care unit admission in patients who present at the emergency department with suspected COVID-19

OBJECTIVES

Develop simple and valid models for predicting mortality and need for intensive care unit (ICU) admission in patients who present at the emergency department (ED) with suspected COVID-19.

DESIGN

Retrospective.

SETTING

Secondary care in four large Dutch hospitals.

PARTICIPANTS

Patients who presented at the ED and were admitted to hospital with suspected COVID-19. We used 5831 first-wave patients who presented between March and August 2020 for model development and 3252 second-wave patients who presented between September and December 2020 for model validation.

OUTCOME MEASURES

We developed separate logistic regression models for in-hospital death and for need for ICU admission, both within 28 days after hospital admission. Based on prior literature, we considered quickly and objectively obtainable patient characteristics, vital parameters and blood test values as predictors. We assessed model performance by the area under the receiver operating characteristic curve (AUC) and by calibration plots.

RESULTS

Of 5831 first-wave patients, 629 (10.8%) died within 28 days after admission. ICU admission was fully recorded for 2633 first-wave patients in 2 hospitals, with 214 (8.1%) ICU admissions within 28 days. A simple model-COVID outcome prediction in the emergency department (COPE)-with age, respiratory rate, C reactive protein, lactate dehydrogenase, albumin and urea captured most of the ability to predict death. COPE was well calibrated and showed good discrimination for mortality in second-wave patients (AUC in four hospitals: 0.82 (95% CI 0.78 to 0.86); 0.82 (95% CI 0.74 to 0.90); 0.79 (95% CI 0.70 to 0.88); 0.83 (95% CI 0.79 to 0.86)). COPE was also able to identify patients at high risk of needing ICU admission in second-wave patients (AUC in two hospitals: 0.84 (95% CI 0.78 to 0.90); 0.81 (95% CI 0.66 to 0.95)).

CONCLUSIONS

COPE is a simple tool that is well able to predict mortality and need for ICU admission in patients who present to the ED with suspected COVID-19 and may help patients and doctors in decision making.

The dolutegravir/valproic acid drug-drug interaction is primarily based on protein displacement

OBJECTIVES

The dolutegravir/valproic acid drug-drug interaction (DDI) is suggested to be caused by protein displacement. Here, we assess the underlying mechanism.

METHODS

Participants in a randomized controlled trial investigating valproic acid as an HIV latency reversing agent were recruited in a predefined pharmacokinetic substudy if they were on once-daily 50 mg dolutegravir-containing combination ART (cART) for >12 months with a plasma HIV-RNA <50 copies/mL (trial registration: ClinicalTrials.gov NCT03525730). Participants were randomized to receive 30 mg/kg/day valproic acid orally (divided into two equal doses) for 14 days or not. Total and unbound dolutegravir concentrations were measured on day 0 (before intake of valproic acid and 6 h after intake of valproic acid) and on days 1, 7, 14 and 42. Intra- and inter-subject dolutegravir concentrations and geometric means (GMs) were evaluated.

RESULTS

Six of 10 participants on dolutegravir were randomized to receive valproic acid. During 14 days of valproic acid treatment, the GM total dolutegravir concentration decreased sharply from 1.36 mg/L on day 0 to 0.85, 0.31 and 0.20 mg/L on days 0, 1, 7 and 14, respectively, while total dolutegravir concentrations in the controls remained comparable during the same period: 1.27-1.49 mg/L. We observed a parallel increase in unbound dolutegravir fractions ranging from 0.39% to 0.58% during valproic acid administration, compared with 0.25% to 0.28% without valproic acid. Unbound dolutegravir concentrations were above the established in vitro EC90 value for unbound dolutegravir in 85% of the tested samples.

CONCLUSIONS

This study confirms protein displacement as the main mechanism for this DDI, although additional mechanisms might be involved too. If dolutegravir is taken with food, this DDI is probably not clinically relevant.

Effective antimicrobial combination in vivo treatment predicted with microcalorimetry screening

Objectives

The worldwide emergence of antibiotic resistance calls for effective exploitation of existing antibiotics. Antibiotic combinations with different modes of action can synergize for successful treatment. In the present study, we used microcalorimetry screening to identify synergistic combination treatments against clinical MDR isolates. The synergistic effects were validated in a murine infection model.

Methods

The synergy of meropenem combined with colistin, rifampicin or amikacin was tested on 12 isolates (1 Escherichia coli, 5 Klebsiella pneumoniae, 3 Pseudomonas aeruginosa and 3 Acinetobacter baumannii) in an isothermal microcalorimeter measuring metabolic activity. One A. baumannii strain was tested with two individual pairings of antibiotic combinations. The microcalorimetric data were used to predict in vivo efficacy in a murine peritonitis/sepsis model. NMRI mice were inoculated intraperitoneally and after 1 h treated with saline, drug X, drug Y or X+Y. Bacterial load was determined by cfu in peritoneal fluid and blood after 4 h.

Results

In vitro, of the 13 combinations tested on the 12 strains, 3 of them exhibited a synergistic reduction in MIC (23% n = 3/13), 5 showed an additive effect (38.5% n = 5/13) and 5 had indifferent or antagonistic effects (38.5% n = 5/13). There was a significant correlation (P = 0.024) between microcalorimetry-screening FIC index values and the log reduction in peritoneal fluid from mice that underwent combination treatment compared with the most effective mono treatment. No such correlation could be found between chequerboard and in vivo results (P = 0.16).

Conclusions

These data support microcalorimetic metabolic readout to predict additive or synergistic effects of combination treatment of MDR infections within hours.

Madurella mycetomatis, the main causative agent of eumycetoma, is highly susceptible to olorofim

Objectives

Eumycetoma is currently treated with a combination of itraconazole therapy and surgery, with limited success. Recently, olorofim, the lead candidate of the orotomides, a novel class of antifungal agents, entered a Phase II trial for the treatment of invasive fungal infections. Here we determined the activity of olorofim against Madurella mycetomatis, the main causative agent of eumycetoma.

Methods

Activity of olorofim against M. mycetomatis was determined by in silico comparison of the target gene, dihydroorotate dehydrogenase (DHODH), and in vitro susceptibility testing. We also investigated the in vitro interaction between olorofim and itraconazole against M. mycetomatis.

Results

M. mycetomatis and Aspergillus fumigatus share six out of seven predicted binding residues in their DHODH DNA sequence, predicting susceptibility to olorofim. Olorofim demonstrated excellent potency against M. mycetomatis in vivo with MICs ranging from 0.004 to 0.125 mg/L and an MIC₉₀ of 0.063 mg/L. Olorofim MICs were mostly one dilution step lower than the itraconazole MICs. In vitro interaction studies demonstrated that olorofim and itraconazole work indifferently when combined.

Conclusions

We demonstrated olorofim has potent in vitro activity against M. mycetomatis and should be further evaluated in vivo as a treatment option for this disease.

Trends, seasonality and the association between outpatient antibiotic use and antimicrobial resistance among urinary bacteria in the Netherlands

OBJECTIVES

To determine trends, seasonality and the association between community antibiotic use and antimicrobial resistance (AMR) in Escherichia coli and Klebsiella pneumoniae in urinary tract infections.

METHODS

We analysed Dutch national databases from January 2008 to December 2016 regarding antibiotic use and AMR for nitrofurantoin, trimethoprim, fosfomycin and ciprofloxacin. Antibiotic use was expressed as DDD/1000 inhabitant-days (DID) and AMR was expressed as the percentage of resistance from total tested isolates. Temporal trends and seasonality were analysed with autoregressive integrated moving average (ARIMA) models. Each antibiotic use-resistance combination was cross-correlated with a linear regression of the ARIMA residuals.

RESULTS

The trends of DID increased for ciprofloxacin, fosfomycin and nitrofurantoin, but decreased for trimethoprim. Similar trends were found in E. coli and K. pneumoniae resistance to the same antibiotics, except for K. pneumoniae resistance to ciprofloxacin, which decreased. Resistance levels peaked in winter/spring, whereas antibiotic use peaked in summer/autumn. In univariate analysis, the strongest and most significant cross-correlations were approximately 0.20, and had a time delay of 3-6 months between changes in antibiotic use and changes in resistance. In multivariate analysis, significant effects of nitrofurantoin use and ciprofloxacin use on resistance to these antibiotics were found in E. coli and K. pneumoniae, respectively. There was a significant association of nitrofurantoin use with trimethoprim resistance in K. pneumoniae after adjusting for trimethoprim use.

CONCLUSIONS

We found a relatively low use of antibiotics and resistance levels over a 9 year period. Although the correlations were weak, variations in antibiotic use for these four antibiotics were associated with subsequent variations in AMR in urinary pathogens.

Melanin production in coelomycetous agents of black grain eumycetoma

Background

Eumycetoma is a fungal infection characterised by the formation of black grains by causative agents. The melanin biosynthetic pathways used by the most common causative agents of black-grain mycetoma are unknown and unravelling them could identify potential new therapeutic targets.

Method

Melanin biosynthetic pathways in the causative fungi were identified by the use of specific melanin inhibitors.

Results

In Trematosphaeria grisea and Falciformispora tompkinsii, 1,8-dihydroxynaphthalene (DHN)-melanin synthesis was inhibited, while DHN-, 3,4-dihydroxyphenylalanine (DOPA)- and pyo-melanin were inhibited in Medicopsis romeroi and Falciformispora senegalensis.

Conclusion

Our data suggest that Me. romeroi and F. senegalensis synthesise DHN-, DOPA- and pyo-melanin, while T. grisea and F. tompkinsii only synthesise DHN-melanin.

Prevalence of and risk factors for extended-spectrum beta-lactamase genes carriership in a population-based cohort of middle-aged and elderly

INTRODUCTION

Increasing resistance to beta-lactam antibiotics is an alarming development worldwide. Fecal carriership of TEM, SHV, CTX-M and CMY was studied in a community-dwelling population of middle-aged and elderly individuals.

PATIENTS AND METHODS

Feces was obtained from individuals of the Rotterdam Study. Carriership of the TEM, SHV, CTX-M and CMY genes was determined using real-time polymerase chain reaction (qPCR). Possible associations were investigated between carriership of these genes and several risk factors, such as the use of antimicrobial drugs, diabetes mellitus, protein pump inhibitor (PPI) use, travelling, the composition of the gut microbiota, and intake of certain foods.

RESULTS

The most prevalent gene was TEM (53.0%), followed by SHV (18.4%), CTX-M (5.4%) and CMY (3.6%). Use of penicillins with extended spectrum was associated with TEM carriership, whereas use of macrolides and lincosamides was associated with TEM and SHV carriership. Interestingly, use of PPIs was associated with a higher prevalence of carriership of TEM, SHV and CMY (TEM: odds ratio [OR] 1.34; 95% confidence interval [CI] 1.05-1.77; SHV: OR 2.17; 95%CI 1.55-2.87; CMY: OR 2.26; 95%CI 1.23-4.11). Furthermore, associations were found between the richness and composition of the gut microbiota and TEM and SHV carriership.

CONCLUSIONS

The prevalence of carriership of TEM was substantial, but the prevalence of carriership of the extended-spectrum β-lactamase gene, CTX-M and the AmpC β-lactamase gene, CMY was relatively low in this community-dwelling, population-based cohort. The composition of the microbiota might play a role in the retention of resistance genes, but future studies are necessary to further elucidate this relationship.

Significant impact of COVID-19 on HIV care in hospitals affecting the first pillar of the HIV care continuum

During COVID-19 lockdown, the in-hospital number of HIV indicator conditions decreased disproportionally compared to other non-COVID-19 diseases which was accompanied by reduced HIV testing rates, number and proportion of positive HIV tests, and new HIV referrals with more late presentation after lockdown cessation, indicating a significantly impacted HIV care continuum.

Transmission of NS5A-Inhibitor Resistance-Associated Substitutions Among Men Who Have Sex With Men Recently Infected with Hepatitis C Virus Genotype 1a

The transmission of direct-acting antiviral resistance-associated substitutions (RAS) could hamper hepatitis C virus (HCV) cure rates and elimination efforts. A phylogenetic analysis of 87 men who have sex with men recently infected with HCV genotype 1a placed one-third (28/87) in a large cluster, in which 96% harbored NS5A M28V RAS.

Paracetamol modulates biofilm formation in Staphylococcus aureus clonal complex 8 strains

Staphylococcus aureus biofilms are a major problem in modern healthcare due to their resistance to immune system defenses and antibiotic treatments. Certain analgesic agents are able to modulate S. aureus biofilm formation, but currently no evidence exists if paracetamol, often combined with antibiotic treatment, also has this effect. Therefore, we aimed to investigate if paracetamol can modulate S. aureus biofilm formation. Considering that certain regulatory pathways for biofilm formation and virulence factor production by S. aureus are linked, we further investigated the effect of paracetamol on immune modulator production. The in vitro biofilm mass of 21 S. aureus strains from 9 genetic backgrounds was measured in the presence of paracetamol. Based on biofilm mass quantity, we further investigated paracetamol-induced biofilm alterations using a bacterial viability assay combined with N-Acetylglucosamine staining. Isothermal microcalorimetry was used to monitor the effect of paracetamol on bacterial metabolism within biofilms and green fluorescent protein (GFP) promoter fusion technology for transcription of staphylococcal complement inhibitor (SCIN). Clinically relevant concentrations of paracetamol enhanced biofilm formation particularly among strains belonging to clonal complex 8 (CC8), but had minimal effect on S. aureus planktonic growth. The increase of biofilm mass can be attributed to the marked increase of N-Acetylglucosamine containing components of the extracellular matrix, presumably polysaccharide intercellular adhesion. Biofilms of RN6390A (CC8) showed a significant increase in the immune modulator SCIN transcription during co-incubation with low concentrations of paracetamol. Our data indicate that paracetamol can enhance biofilm formation. The clinical relevance needs to be further investigated.