Patient characteristics, presentation, causal microorganisms, and overall mortality in the NatIonal Danish endocarditis stUdieS (NIDUS) registry

BACKGROUND

Most knowledge on infective endocarditis (IE) comes from large IE cohorts that include patients from tertiary hospitals, leading to referral bias and retrospective population-based studies. This highlights the need for a more detailed characterization of IE in unselected patient cohorts.

METHODS

In the National Danish Endocarditis Studies (NIDUS) registry, all hospitalizations in Denmark from 2016 to 2021 with an IE diagnosis were reviewed and validated using electronic medical records (EMR) by healthcare professionals under the supervision of IE experts. Episodes meeting the European Society of Cardiology 2015 modified diagnostic criteria for possible or definite IE were included.

RESULTS

We screened 4390 unique patients, of whom 3557 (81%) were included in the NIDUS registry. Of the 3557 unique patients, 2832 (79.6%) were classified as definite IE and 725 (20.4%) as possible IE. The age was 73.7 years, and most patients were men (68.3%). In total, 689 (19.4%) underwent surgery during hospitalization. The most frequent comorbidities were diabetes (23.7%), heart failure (18.7%), and chronic kidney disease (17.4%). Most patients presented with fever (61.1%), followed by dyspnea (33.0%) and myalgias (27.0%). Sepsis was found in 828 (23.3%) patients, while 378 (10.6%) had signs of embolization at admission. Positive blood cultures were identified in 3191 (89.7%) patients, and the most frequent microbiological etiology was Staphylococcus aureus (31.9%). The in-hospital mortality was 17.3%, and the 1-year mortality rate was 31.3%.

CONCLUSION

The NatIonal Danish endocarditis studies (NIDUS) registry provides comprehensive, granular, and nationwide data on a cohort of patients with infective endocarditis, revealing that when selection is not restricted to tertiary hospitals or voluntary registries, some important differences emerge. Patients with IE are on average older, have a similar burden of comorbidities, and less often undergo surgery. Minimizing selection bias with the use of a national registry provides a clearer picture of IE as it occurs in real-world clinical settings.

Comparative Outcomes of Mitral Valve Repair Versus Replacement in Infective Endocarditis: A 16-Year Meta-Analysis of Time-to-Event Data From Over 4000 Patients

Mitral valve (MV) repair for infective endocarditis (IE) has proven to be a good and safe option, but current trends favor replacement; the available data, in addition, don't allow to reach a general consensus on the preferred first-line approach. The present metanalysis, aimed to compare short- and long-term outcomes between MV repair (MVRep) and MV replacement (MVR) in patients with IE. A search of PubMed was conducted on 30th August 2024, yielding 120 results. (PROSPERO CRD: CRD42023490612). Four additional suitable studies were identified and added from Embase and Medline (via Ovid). Statistical analyses were performed using RStudio, SPSS, and RevMan. Pseudoindividual patient data were extracted from Kaplan-Meier curves by converting the graphical plots into raw data coordinates through WebPlotDigitizer. A total of 21 studies were eligible for inclusion. The 16-year reconstructed analysis revealed that patients undergoing MVRep have higher survival compared to the MVR group (HR: 1.41, 95% Cl: 1.30-1.53, p < 0.001). Moreover, IE recurrence was significantly lower in MVRep (95% CI, RR:0.46, 12 = 41%, p = 0.03). Reoperation rates, however, were similar between MVRep and MVR (95% CI, RR: 0.78, 12 = 0%, p = 0.27). In-hospital mortality was similar between the groups (95% CI, RR:0.40, 12 = 34%, p = 0.07). In conclusion, MV repair should be favored over replacement in IE when there is no evidence of local extension of the infections and if valve leaflets have not degenerated. This approach is associated with improved overall survival and a reduced risk of IE recurrence, making it particularly advantageous for younger patients.

Epidemiological Profile and Mortality of Infective Endocarditis Over the Past Decade: A Systematic Review and Meta-Analysis of 133 Studies

Infective endocarditis (IE) is an increasingly prevalent condition with relatively high mortality, whose epidemiology has become more complex with an aging population, an increased number of comorbidities, and an increasing incidence of health-care associated IE. Epidemiological data on the causative microorganisms of IE, prevalence of involvement of the different cardiac valves, and IE-associated mortality are clinically relevant. Eligible studies were identified through a systematic search of PubMed/MEDLINE database from 2010 to 2020, and a random effects model meta-analysis was conducted. 133 studies comprising 132,584 patients from six continents were included in this systematic review. The most common causative agents were Staphylococci species in 36% of cases, followed by Streptococci species (26%) and Enterococci species (10%). Out of studies that provided further speciation, the predominant species was Staphylococcus aureus with an incidence of 29%, followed by Viridans group Streptococcus (12%). The short-term mortality rate (defined as in-hospital or 30-day mortality) was 17%. The highest mortality was reported in studies from Latin America with a mean mortality rate of 33% and the lowest mortality was reported in studies from Oceania at 13%. The aortic valve was the most commonly affected valve (46%), followed closely by the mitral valve (43%). The prevalence of tricuspid valve IE was 7% and multivalvular IE occurred in 14% of cases. Our study highlights a shift in epidemiological profile of IE over the last decade with S. aureus identified as the most common causative microorganism of IE. PROTOCOL REGISTRATION: PROSPERO CRD42024602342.

Gene expressions of clinical Pseudomonas aeruginosa harboring RND efflux pumps on chromosome and involving a novel integron on a plasmid

The clinical strain of Pseudomonas aeruginosa XM8 harbored multiple RND-type antibiotic efflux pump genes and a novel integron In4881 on its plasmid pXM8-2, rendering it resistant to nearly all conventional antibiotics except colistin. The resistance was primarily attributed to the inactivation of the oprD gene and overexpression of several efflux pump genes, including mexAB-oprM, mexCD-oprJ, oprN-mexFE, and mexXY. In this study, the XM8 strain was comprehensively characterized using various methods. Antimicrobial susceptibility testing was performed using the BioMerieux VITEK2 system and manual double dilution methods. Gene expression levels of efflux pump-related genes were analyzed via quantitative real-time PCR. The bacterial chromosome and plasmid were sequenced using both Illumina and Nanopore platforms, and bioinformatics tools were employed to analyze mobile genetic elements associated with antibiotic resistance. The pXM8-2 plasmid containsed multiple mobile genetic elements, including integrons (In4881, In334, In413) and transposons (Tn3, TnAs1, TnAs3). Notably, In4881 was reported for the first time in this study. The presence of these elements highlights the potential for horizontal gene transfer and further spread of antibiotic resistance. Given the strong resistance profile of the XM8 strain, effective measures should be implemented to prevent the dissemination and prevalence of such multidrug-resistant bacteria.

Modified tree-based selection in hierarchical mixed-effect models with trees: A simulation study and real-data application

Hierarchical mixed-effects models with three trees-3Trees models-are a new advanced statistical learning approach in mixed-effect modeling. These methods utilize the classification and regression trees (CART) algorithm to select the best tree through a backfitting algorithm. However, this algorithm relies on a greedy approach, making the trees prone to overfitting, biased in split selection, and often far from the optimal solution, ultimately affecting model performance. Two novel methods are proposed-3Trees-EvTree and 3Trees-CTree-to address these limitations. The proposed methods are compared with the available methods through several simulation exercises in different settings and real datasets. The simulation study confirms that the 3Trees-EvTree method performs well compared to the previous method in terms of parameter estimation and prediction accuracy under clusMSE and clusPMSE. Meanwhile, the 3Trees-CTree model performs well in low-correlation scenarios and the semilinear function. In addition, the proposed methods also reveal that the results of actual application confirm their superiority over other competing methods. Some highlights of the proposed method are:•3Trees-EvTree and 3Trees-CTree model to improve prediction accuracy and to reduce bias of 3Trees model are presented•MSE, ClusMSE, PMSE, ClusPMSE, and bias criteria are used to evaluate model performance•Applied to estimate and predict household expenditure per capita dataset.

Luteolin inhibits inflammation and M1 macrophage polarization in the treatment of Pseudomonas aeruginosa-induced acute pneumonia through suppressing EGFR/PI3K/AKT/NF-κB and EGFR/ERK/AP-1 signaling pathways

BACKGROUND

The opportunistic pathogen Pseudomonas aeruginosa primarily causes infections in immunocompromised individuals. Luteolin, a natural flavonoid, is widely present in plants, which exerts various pharmacological activities, including anti-inflammatory and antimicrobial activities.

PURPOSE

This study aimed to explore the therapeutic efficacy of luteolin and the underlying molecular mechanisms in treating the P. aeruginosa-induced acute pneumonia.

METHODS

Network pharmacology was utilized to identify the core targets of luteolin for treating acute P. aeruginosa pneumonia. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed to dissect the potential effects of luteolin and the involved signaling pathways. Surface plasmon resonance (SPR) assay and molecular docking were employed for studying the binding affinities of luteolin with the key targets. Furthermore, we applied a mouse model of bacterial pneumonia for assessing the therapeutic effects of luteolin in vivo, and an in vitro infection model for specifically investigating the effects of luteolin on macrophages as well as the underlying mechanisms upon P. aeruginosa infection.

RESULTS

Network pharmacology identified TNF, IL-6, EGFR and AKT1 as the key targets of luteolin for treating acute P. aeruginosa pneumonia. Moreover, as revealed by GO and KEGG enrichment analysis, EGFR, MAPK and PI3K/AKT pathways were the potential pathways regulated the P. aeruginosa-induced inflammatory response. According to the in vivo results, luteolin effectively mitigated the P. aeruginosa-induced acute lung injury through reducing the pulmonary permeability, neutrophil infiltration, proinflammatory cytokine production (IL-1β, IL-6, TNF and MIP-2) and bacterial burden in lung tissues, which led to increased survival rate of mice. Furthermore, the luteolin-treated mice had diminished EGFR, PI3K, AKT, IκBα, NF-κB p65, ERK, c-Jun and c-Fos phosphorylation, down-regulated M1 macrophage marker levels (iNOS, CD86 and IL-1β) but up-regulated M2 macrophage marker levels (Ym1, CD206 and Arg1) in lung tissues. Consistently, the luteolin-pretreated macrophages exhibited reduced phosphorylation of these regulatory proteins, diminished proinflammatory cytokine production, and down-regulated expression of M1 macrophage markers, but up-regulated expression of IL-10 and M2 macrophage markers.

CONCLUSION

luteolin effectively suppressed the inflammatory responses and M1 macrophage polarization through inhibiting EGFR/PI3K/AKT/NF-κB and EGFR/ERK/AP-1 signaling pathways in the treatment of acute P. aeruginosa pneumonia. This study suggests that luteolin could be a promising candidate for development as a therapeutic agent for acute bacterial pneumonia.

Trends of infective endocarditis mortality in young adult population of US: A concerning rise and its association with substance abuse

Background

Substance Abuse (SA) is associated with Infective Endocarditis (IE) morbidity and mortality in the young adult population of the US. However, limited data is available for trends and disparities related to IE mortality and its association with SA in the young adult US population.

Methods

Data from the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research were analyzed from 1999 to 2022 for IE and SA-IE-related mortality in young adults aged 15 to 44 in the US. Age-adjusted mortality rates (AAMR) per 1000,000 people were used to calculate annual percent changes (APC) using Joinpoint regression analysis. Trends were stratified by sex, race/ethnicity, age groups, census region, urbanization classification, and states.

Results

IE caused 22,614 deaths in the young adult population of the US between 1999 and 2022. 7235 (32.0 %) of these deaths were associated with SA. AAMR for IE-associated mortality initially decreased from 6.2 in 1999 to 4.7 in 2010. Following that it increased by almost 3 folds to reach 13.5 in 2020 and 2021. SA-IE followed a similar trend, increasing more than 5 folds from an AAMR of 1.0 in 2010 to 5.4 by 2018. Between 1999 and 2009, 15-22 % of all IE deaths were associated with SA annually, which increased to >40 % for 2016-2022. Men had higher AAMR for IE though women witnessed a bigger jump in SA-associated IE mortality. Non-Hispanic American Indian or Alaskan natives, South region, and rural population had a worse increase.

Conclusions

IE mortality in the young adult population of the US has increased from 2010 onwards with a concerning rise in SA and IE-associated deaths.

Debridement, Antibiotics and Implant Retention: Are all approaches to periprosthetic joint infection equal? Same procedures, different outcomes

BACKGROUND

The reported success rate of debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection varies considerably between studies, despite institutions reporting use of the same procedure. In this narrative review, we aim to delineate the differences between the various DAIR approaches and highlight why they influence the outcome.

OBJECTIVES

We performed a PubMed and internet search investigating the different approaches for DAIR and their associated outcomes.

SOURCES

Twenty-two studies with defined infection criteria, consisting of 50 or more PJI cases and a follow-up of one year or longer were included.

CONTENT

Most studies did not report whether the presence of a sinus tract was a criterion for not performing DAIR, and the use of biofilm-active agents for curative DAIR was only reported in a few studies. The duration of infection as criterion for early postoperative and acute hematogenous infection varied between studies. The epidemiology of host factors and microorganisms, healthcare systems, patient-doctor-interactions and decision-making processes for surgical interventions vary worldwide, and so do the indications for DAIR.

IMPLICATIONS

Studies should precisely declare the indication for DAIR, the variables that influence decision-making for treatment options, the surgical technique applied and the type and duration of antimicrobial therapy. Such an approach will increase the quality of research data and allow the development of recognized subcategories of DAIR.

Shoulder Arthroplasty: Current Evidence and Techniques on Infection Diagnosis and Treatment

The incidence of shoulder arthroplasty is increasing with rapidly expanding indications. Although the procedure is becoming increasingly successful, complications do occur. Prosthetic joint infection of the shoulder (PJIS) is a devastating complication that requires dedicated efforts for diagnosis and eradication. As a supplement to our accompanying article on the topic of PJIS prevention, we review the current approaches to diagnosing and treating PJIS.

Cefazolin is Associated with a Lower Periprosthetic Joint Infection Risk than Alternative Antibiotic Regimens Following Total Hip Arthroplasty

INTRODUCTION

There have been conflicting reports on the risk of periprosthetic joint infection (PJI) with the use of alternative antibiotics to cefazolin following arthroplasty. We leveraged recent data from a nationally representative multi-payer dataset to investigate this question.

METHODS

We queried a healthcare dataset from 2016 to 2022 to identify primary total hip arthroplasties (THAs) using Current Procedural Terminology (CPT) and International Classification of Disease-Procedure Coding System (ICD-PCS) codes (27130, 0SR90xx, 0SRB0xx) with a corresponding osteoarthritis diagnosis (International Classification of Disease-Clinical Modification (ICD-CM): M16). Patient demographics, characteristics, and outcomes were extracted from existing dataset variables. The PJIs were defined using ICD-10 diagnosis codes from the Centers for Medicare & Medicaid Services' procedure-specific complication measure within 90 days of surgery. We compared PJI between patients receiving cefazolin antibiotic prophylaxis and patients who received an alternative antibiotic or cefazolin plus another antibiotic. The association between cefazolin use and PJI was evaluated using multinomial logistic regression. This study included 289,369 primary THA patients from 2016 to 2022. There were 25,164 patients (8.7%) who received a non-cefazolin antibiotic, 200,367 (69.2%) received cefazolin only, and 63,838 (22.1%) received cefazolin plus an alternative antibiotic.

RESULTS

In univariate analysis, there was a significant difference in the rate of 90-day PJI between the non-cefazolin group, cefazolin only, and cefazolin plus other antibiotic group (0.9, 0.5, and 0.5%, respectively, P < 0.001). In a logistic regression analysis that adjusted for age, sex, payer, race, ethnicity, and Elixhauser Comorbidity Index, the use of cefazolin only and cefazolin plus other antibiotic, were associated with reduced risk of 90-day PJI [OR (odds ratio) 0.62, 95% CI (confidence interval) (0.53 to 0.72), P < 0.001] and [OR 0.64, 95% CI (0.54 to 0.76), P < 0.001].

CONCLUSIONS

In this nationally representative multi-payer study using recent data, patients who received antibiotic prophylaxis with cefazolin had lower 90-day rates of PJI compared to those receiving alternative antibiotics during primary total hip arthroplasty.

Construction of a thiophene-based conjugated polymer/TP-PCN S-scheme to enhance visible-light-driven photocatalytic activity: Promotion of wound healing in super-resistant bacterial infections

S-scheme heterojunctions have garnered significant attention in the field of photocatalytic antimicrobials due to their superior charge separation efficiency and higher redox capacity. In this study, an innovative linear conjugated polymer (PCO) was combined with fragmented carbon nitride (TP-PCN) to create PCO/TP-PCN organic-organic S-scheme heterojunctions, which markedly enhanced the photocatalytic antimicrobial performance. The composite (PCO-7/TP-PCN) demonstrated the ability to combat bacterial infections under visible light irradiation, effectively eradicating approximately 2.16 × 107 cfu/ml MRSA within 6 min. This exceptional photocatalytic performance can be attributed to the successful formation of an S-scheme heterojunction between PCO and TP-PCN, as well as the interaction of surface functional groups of PCO-7/TP-PCN with bacteria. Results from UV-Vis-NIR DRS and in situ-XPS experiments indicated a significant enhancement in carrier transport rate through the establishment of a built-in electric field and energy band bending at the interface. In vitro and in vivo experiments further demonstrated that PCO-7/TP-PCN not only exhibited potent antimicrobial activity under visible light irradiation but also promoted angiogenesis to inhibit inflammatory responses. Therefore, it can be concluded that this organic-organic S-scheme heterojunction photocatalyst holds great potential for development as a promising new generation of efficient antimicrobial materials, which could aid in preventing bacterial infection of wounds and ensuring effective wound healing.

Ceftazidime-avibactam plus aztreonam cocktail for the treatment of VIM-producing Pseudomonas aeruginosa infections: good enough to have another?

BACKGROUND

Few active antibiotic options are available to treat MBL-producing Pseudomonas aeruginosa infections, and some of these options are either poorly tolerated or have pharmacokinetic limitations. The use of aztreonam monotherapy for treating MBL-producing P. aeruginosa remains controversial due to the risk of selecting resistant mutants during treatment.

OBJECTIVES

To describe the clinical outcomes of patients treated with ceftazidime-avibactam plus aztreonam for VIM-producing P. aeruginosa infections. The assessed outcomes include clinical success, clinical cure, all-cause mortality at day 28, combination therapy-associated adverse events, infection relapse and microbiological recurrence.

METHODS

This retrospective observational single-centre study was conducted at Clínica Universidad de Navarra, Pamplona, Spain. Eight patients with VIM-producing P. aeruginosa infections were included. Whole-genome sequencing of isolates was performed at Hospital Universitario Son Espases, Palma, Spain.

RESULTS

All isolates were susceptible to aztreonam and aztreonam-avibactam. No resistance mechanisms against these antibiotics were identified through whole-genome sequencing, except in one isolate that overexpressed the MexAB-OprM efflux pump. Clinical success and clinical cure were achieved in seven of eight patients, while all-cause mortality at day 28 was two of eight. Clinical cure was documented for five different infections and three distinct P. aeruginosa clones. No adverse events related to antibiotic therapy were reported, and no infection relapses occurred after treatment. Microbiological recurrence was observed in two cases.

CONCLUSIONS

In our experience, patients with VIM-producing P. aeruginosa infections treated with ceftazidime-avibactam plus aztreonam mostly achieved clinical success. However, given the limited sample size, further research is required to validate these findings.

Antipseudomonal cephalosporins versus piperacillin/tazobactam or carbapenems for the definitive antibiotic treatment of Pseudomonas aeruginosa bacteraemia: new kids on the ICU block?

BACKGROUND

Pseudomonas aeruginosa bloodstream infections (Pa-BSIs) are still a major cause of mortality in ICUs, posing many treatment uncertainties.

METHODS

This multicentre, retrospective study analysed data from 14 Italian hospitals, including all consecutive adults developing Pa-BSI in ICU during 2021-22 and treated with antibiotics for at least 48 h. The primary aim was to identify predictors of 30 day mortality using Cox regression. Results were adjusted with inverse probability of treatment weighting (IPTW) and for immortal time bias.

RESULTS

Overall, 170 patients were included. High-risk BSI (source: lung, intra-abdominal, CNS) occurred in 118 (69%) patients, and 54 (32%) had septic shock. In 37 (22%), 73 (43%), 12 (7%) and 48 (28%) the definitive backbone therapy was piperacillin/tazobactam, carbapenems, colistin or new antipseudomonal cephalosporins (ceftolozane/tazobactam, n = 20; ceftazidime/avibactam, n = 22; cefiderocol, n = 6), respectively. Moreover, 58 (34%) received a second drug as combination therapy. The incidence of 30 day all-cause mortality was 27.6% (47 patients). By Cox regression, Charlson comorbidity index, neutropenia, septic shock and high-risk BSI were independent predictors of 30 day mortality, while previous colonization by P. aeruginosa, use of antipseudomonal cephalosporins as definitive treatment, and combination therapy were shown to be protective. However, after IPTW adjustment, only the protective effect of antipseudomonal cephalosporins was confirmed (adjusted HR = 0.27, 95% CI = 0.10-0.69), but not for combination therapy. Hence, the treatment effect was calculated: antipseudomonal cephalosporins significantly reduced mortality risk [-17% (95% CI = -4% to -30%)], while combination therapy was beneficial only in the case of septic shock [-66% (95% CI = -44% to -88%].

CONCLUSIONS

In ICU, antipseudomonal cephalosporins may be the preferred target therapy for the treatment of Pa-BSI; in addition, initial combination therapy may be protective in the case of septic shock.

Moving Beyond Systemic Inflammatory Response Syndrome and Bacteremia: Are Modern Critical Care Calculators Useful in Predicting Debridement, Antibiotics, and Implant Retention Treatment Outcomes in Periprosthetic Joint Infection?

BACKGROUND

In critically ill periprosthetic joint infection (PJI) patients, surgeons need to balance the need for aggressive, definitive treatment against the health state of a potentially unstable patient. A clear understanding of the association between treatment outcomes and assessment scores for sepsis would benefit clinical decision-making in these urgent cases. The current study evaluates the effect of critical illness on debridement, antibiotics, and implant retention (DAIR) outcomes, as defined by systemic inflammatory response syndrome (SIRS) and, for the first time, by contemporary markers quick sequential organ failure assessment (qSOFA) and Modified Early Warning Score (MEWS).

METHODS

We retrospectively identified 253 patients who underwent DAIR for PJI at a single institution between 2017 and 2021. The SIRS, qSOFA, and MEWS scores were calculated based on variables on admission. A DAIR treatment failure, defined as reoperation or mortality, was measured at 90 days and two years. Univariate analysis was used to determine the association between elevated critical care scores and DAIR failure.

RESULTS

The DAIR treatment success was 59% at two years, with hip procedures and Charlson comorbidity index ≥ one independently associated with higher odds of DAIR failure. There were 43 patients (16%) who presented with SIRS; however, only four (2%) had positive qSOFA scores. Neither SIRS nor qSOFA was predictive of DAIR failure. Only for knees, elevated MEWS scores were predictive of 90-day DAIR failure (P = 0.019).

CONCLUSIONS

Over one in six patients undergoing DAIR for PJI presented with SIRS, while only one in 50 had a positive qSOFA. The SIRS and qSOFA scores were not predictive of DAIR failure. Elevated MEWS scores were associated with DAIR failure at 90 days postoperatively in knee PJIs only and should be confirmed in a larger cohort. Our results suggest that SIRS is not predictive of DAIR outcomes, possibly because it overestimates the proportion of critically ill patients.

Systematic mining and quantification reveal the dominant contribution of non-HLA variations to acute graft-versus-host disease

Human leukocyte antigen (HLA) disparity between donors and recipients is a key determinant triggering intense alloreactivity, leading to a lethal complication, namely, acute graft-versus-host disease (aGVHD), after allogeneic transplantation. Moreover, aGVHD remains a cause of mortality after HLA-matched allogeneic transplantation. Protocols for HLA-haploidentical hematopoietic cell transplantation (haploHCT) have been established successfully and widely applied, further highlighting the urgency of performing panoramic screening of non-HLA variations correlated with aGVHD. On the basis of our time-consecutive large haploHCT cohort (with a homogenous discovery set and an extended confirmatory set), we first delineated the genetic landscape of 1366 samples to quantitatively model aGVHD risk by assessing the contributions of HLA and non-HLA genes together with clinical factors. In addition to identifying multiple loss-of-function (LoF) risk variations in non-HLA coding genes, our data-driven study revealed that non-HLA genetic variations, independent of HLA disparity, contributed the most to the occurrence of aGVHD. This unexpected major effect was verified in an independent cohort that received HLA-identical sibling HCT. Subsequent functional experiments further revealed the roles of a representative non-HLA LoF gene and LoF gene pair in regulating the alloreactivity of primary human T cells. Our findings highlight the importance of non-HLA genetic risk in the new era of transplantation and propose a new direction to explore the immunogenetic mechanism of alloreactivity and to optimize donor selection strategies for allogeneic transplantation.

Addressing carbapenemase-producing extensively drug-resistant Pseudomonas aeruginosa: the potential of cefiderocol and ceftazidime/avibactam plus aztreonam therapy

This study evaluated the activity of cefiderocol and the combination of ceftazidime/avibactam (CZA) plus aztreonam against carbapenemase-producing extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates. Nine clinical XDR P. aeruginosa isolates with different sequence types and class A (GES) or B (VIM, IMP or NDM) carbapenemases were analysed. Time-kill assays assessed bacterial load reduction for each treatment, while chemostat experiments on four isolates validated these findings. All isolates showed resistance to CZA, with four also resistant to aztreonam. Seven isolates were susceptible to cefiderocol, but two displayed borderline susceptibility (MIC 2-4 mg/L). Time-kill assays demonstrated bactericidal activity by cefiderocol in six isolates at 24 h, while CZA plus aztreonam showed bactericidal effects in three isolates and synergistic/additive effects in four isolates. In the chemostat model, cefiderocol and CZA plus aztreonam were bactericidal in all four tested isolates, with cefiderocol showing greater bacterial reduction in three of these isolates. Both cefiderocol and CZA plus aztreonam achieved significant reductions in bacterial counts compared to controls, but there was no significant difference between cefiderocol monotherapy and the combination. Both cefiderocol and CZA plus aztreonam demonstrated activity against XDR P. aeruginosa carrying metallo-β-lactamase (MBL) and/or serine-β-lactamase (SBL) carbapenemases. Cefiderocol was the only consistently effective monotherapy with a bactericidal effect across all tested isolates in the chemostat model.

What is the most effective antibiotic monotherapy for severe Pseudomonas aeruginosa infection? A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVES

Severe infections caused by Pseudomonas aeruginosa are associated with significant morbidity and mortality, particularly in hospitalized and immunocompromised patients. Determining the optimal definitive monotherapy for these infections is critical. The main objective was to compile the evidence of subgroups of patients with Pseudomonas aeruginosa infection from randomized control trials (RCTs) evaluating different definite antipseudomonal monotherapies for severe P. aeruginosa infection.

METHODS

Systematic review and meta-analysis of RCTs that assessed monotherapy with an antipseudomonal drug versus another antipseudomonal for definite treatment, and reported on the subgroup of patients with P. aeruginosa infection. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, LILACS and the reference lists of included trials. Eligibility criteria included RCTs enrolling hospitalized adults (≥18 years) with microbiologically confirmed severe P. aeruginosa infections. Studies were excluded if they included >20% of patients receiving combination therapy or if patients had resistant P. aeruginosa strains at recruitment. Antipseudomonal drugs evaluated included cephalosporins, carbapenems, penicillins, quinolones and aztreonam. The primary outcome was 30-day mortality. Risk of bias was assessed using the Cochrane tool. Results were pooled using fixed-effects and random-effects models as appropriate. Relative risk (RR) and 95% CIs were calculated. Sensitivity analyses and subgroup analyses were performed when data were available.

RESULTS

A total of 76 RCTs and 1681 patients with pseudomonal infection were included. Due to the low number of studies which reported our outcomes of interest, all subgroup analyses were underpowered. No difference in all-cause mortality was found for any direct antibiotic comparison. Higher clinical failure rates of carbapenems versus piperacillin-tazobactam were observed for pneumonia in two RCTs (RR, 2.55; 95% CI, 1.29-5.03; I2 = 0%, n = 2), and higher microbiological failure rates with carbapenems versus other comparators (RR, 1.24; 95% CI, 1.02-1.51; I2 = 0%, n = 23). Patients treated with imipenem were more likely to develop resistance to the study drug versus comparators (RR, 2.33; 95% CI, 1.61-3.38; I2 = 0%, n = 7).

CONCLUSIONS

In this systematic review and meta-analysis of definite antipseudomonal monotherapy for P. aeruginosa infection, we found no evidence of clinical benefit differences among direct antibiotic comparisons, but all subgroup analyses were underpowered to detect significant differences.

Intra-wound vancomycin powder is cost-saving in primary total hip and knee arthroplasty

PURPOSE

This study seeks to explore whether intra-wound vancomycin powder (IVP) is a cost-effective adjunct to standard of care (SOC) in patients undergoing total joint arthroplasty (TJA) from a US payor perspective.

METHODS

A decision-analytic model in the form of a decision tree was developed to compare the cost and outcomes of IVP with those of SOC in preventing periprosthetic joint infections (PJI) in TJA patients. The base case analysis assumes a hypothetical practice with an equal volume (50/50) of THA and TKA procedures in both the IVP + SOC and the SOC arm. Cost and clinical effectiveness data were obtained from published literature. Sensitivity and threshold analyses were used to estimate how changing inputs would impact the cost-effectiveness of IVP.

RESULTS

Deterministic results found that in the base case model, IVP as an adjunct to SOC generates a cost saving of $260.38/patient. In scenario analysis, where THA and TKA procedures were separated, the estimated cost saving was $241.50/patient and $279.27/patient, respectively. Break-even analysis showed that the cost of IVP per patient would need to be $244.82-$282.59, or the PJI relative risk (RR) be approximately 0.99. Probabilistic analysis found IVP + SOC was cost-saving in 99.26% of the 10,000 iterations in the base case model.

CONCLUSION

Applying local vancomycin as an adjunct to SOC in primary TJA is not just cost effective, but cost-saving in reducing PJIs, saving an average of $260.38/patient. Depending on individual institution/practice infection rates and revision surgery costs, local vancomycin administration for primary TJA should be considered.

Secular trends in periprosthetic joint infections following primary hip and knee arthroplasties: A 15-year cohort study from the VINCat Program (2008-2022)

BACKGROUND

The VINCat program, established in Catalonia, Spain, in 2006, is a comprehensive infection prevention program for healthcare-associated infections. This study aims to analyze long-term trends in periprosthetic joint infections (PJI) following primary hip and knee arthroplasties over 15-year period (2008-2022).

METHODS

PJI was defined according to CDC-NHSN criteria and updated in 2016 to incorporate the Musculoskeletal Infection Society classification. Data on PJI following total hip arthroplasty (THA), total knee arthroplasty (TKA), and hip hemiarthroplasty (HHA) were prospectively collected and analyzed across three periods: 2008-2012, 2013-2017, and 2018-2022.

RESULTS

Sixty-seven hospitals participated in the surveillance, reporting 189,063 procedures, including 61,267 THA (median age: 69 years, 47% female), 115,940 TKA (median age: 73 years, 68% female), and 11,856 HHA (median age: 86 years, 73% females). PJI incidence rates for THA were 0.9%, 1.1%, and 1.2% across the three periods (odds ratio (OR):1.14, 95% CI: 0.96-1.35). For TKA, rates were 0.9%, 1.0%, and 0.9% (OR:0.95, 95% CI: 0.83-1.09). The incidence of HHA-PJI declined from 3.4% to 2.3% and 1.8% (OR:0.77, 95% CI:0.58-1.03). Overall, the most common etiology was coagulase negative staphylococci followed by Staphylococcus aureus. PJIs were diagnosed after hospital discharge in 87.1% of THA, 89.6% of TKA, and 73.9% of HHA.

CONCLUSIONS

The incidence of PJI remains low despite an aging population undergoing orthopedic surgery, highlighting the effectiveness of current infection prevention strategies. A robust, long-term surveillance system is crucial for monitoring epidemiological trends and guiding the implementation of evidence-based preventive measures.

The effect of quaternary ammonium compounds (QACs) on quorum sensing and resistance of P. aeruginosa in clinical settings

Pseudomonas aeruginosa, a formidable opportunistic pathogen, is notorious for its ability to form biofilms and produce virulence factors that favor chronic infections, especially in cystic fibrosis patients. The misuse of disinfectants, combined with environmental leakage and biodegradation, has led to widespread exposure of microorganisms to sub-lethal concentrations of disinfectants, particularly quaternary ammonium compounds (QACs). This study investigates the interaction between QACs, specifically ethylbenzalkyl dimethyl ammonium chloride (EBAC), and the quorum sensing (QS) mechanisms governing P. aeruginosa behavior. The results demonstrate that exposure to sub-minimum inhibitory concentrations (sub-MICs) of EBAC not only enhances the biofilm-forming capability of P. aeruginosa isolates but also modulates the expression of crucial QS-regulated genes. Notably, the bacteria exhibit increased production of biofilm-associated virulence factors such as pyocyanin and elastase, and altered antibiotic susceptibility profiles, indicating a shift towards persistent infection phenotypes. These findings reveal that QAC exposure can significantly increase resistance to antibiotics and external stressors like hydrogen peroxide. These results emphasize the need to reassess the efficacy of QACs in clinical disinfection settings, particularly against P. aeruginosa infections, and highlight the potential for unintended consequences of their use regarding bacterial behavior and virulence. This study provides novel insights into the role of QACs in modulating QS-mediated virulence and antibiotic resistance, offering a new perspective on the risks associated with sub-lethal disinfectant exposure.

Septic arthritis - symptoms, diagnosis and new therapy

Septic arthritis (SA) is an infection of one or more joints caused mainly by Staphylococcus aureus, to a lesser extent by streptococci and Gram-negative bacilli. It poses a huge medical problem due to its high mortality rate of 2-15%. Disease symptoms are often vague, resulting in a risk that SA may be diagnosed too late. This shows the urgency of finding a rapid diagnostic method for SA and an effective therapy. Basic treatment of SA including joint drain or empirical antimicrobial therapy does not always provide the desired results. Hence, new therapies are being sought, including the use of antimicrobial peptide or phage therapy.

Comparison of urinary tract-related and catheter-related bloodstream infections in long-term and acute care wards: A retrospective cohort study

BACKGROUND

The characteristics of bloodstream infections in patients admitted to long-term care wards remain unclear. This study examined differences in nosocomial-onset urinary tract-related bloodstream infections (UTRBSIs) and catheter-related bloodstream infections (CRBSIs) between patients admitted to long-term and acute care wards.

METHODS

This retrospective cohort study was conducted at a mixed-care hospital with long-term and acute care wards from April 2015 to March 2024. Patient backgrounds, causative pathogens, antibiotic resistance, and treatment patterns were compared between the two groups.

RESULTS

Among the 252 patients, 108 (42.9 %) were diagnosed with UTRBSIs and 87 (34.5 %) with CRBSIs. In UTRBSIs, the long-term care group had significantly longer hospitalization (721 vs. 16 days, P < 0.001), more frequent use of indwelling urinary catheters (76.7 % vs. 28.6 %, P < 0.001), and higher isolation rates of extended-spectrum β-lactamase-producing Enterobacterales (41.1 % vs. 8.6 %, P < 0.001). Piperacillin/tazobactam and meropenem were significantly more frequently used empirically in the long-term care group. In CRBSIs, the isolation rates of main causative pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) (9.5 % vs. 6.7 %, P = 0.707) and methicillin-resistant coagulase-negative Staphylococcus spp. (40.5 % vs. 48.9 %, P = 0.519), showed no significant differences between the two groups despite differences in patient backgrounds. Anti-MRSA agents were rarely used empirically in both groups (19.0 % vs. 15.6 %, P = 0.779).

CONCLUSIONS

Patients admitted to long-term care wards may require empirical therapy for UTRBSIs targeting drug-resistant Enterobacterales, while for CRBSIs, empirical use of anti-MRSA agents may be considered, similar to patients admitted to acute care wards.

Incidence, case-fatality rates and risk factors of bloodstream infections caused by Escherichia coli, Klebsiella species and Pseudomonas aeruginosa, England, April 2017 to March 2022

BackgroundEscherichia coli, Klebsiella spp. and Pseudomonas aeruginosa are included in the mandatory surveillance of bloodstream infections (BSI) in England.AimWe aimed to investigate the epidemiology of these BSIs in England April 2017-March 2022.MethodsWe extracted data on E. coli, Klebsiella spp. and P. aeruginosa BSI, categorised BSIs as healthcare-associated (HA) or community-associated (CA) and linked to antimicrobial susceptibility and mortality data. We used multivariable logistic regression models to assess predictors of mortality.ResultsThe incidence rate of E. coli BSI was 71.8 per 100,000 population (95% confidence interval (CI): 71.5-72.1), Klebsiella spp. 19.1 (95% CI: 18.9-19.3) and P. aeruginosa 7.6 (95% CI: 7.5-7.7). Most (65,467/104,957) BSI episodes were CA. Case-fatality rate was 14.8% (95% CI: 14.6-14.9) in E. coli, 20.0% (95% CI: 19.6-20.3) in Klebsiella spp. and 25.8% (95% CI: 25.2-26.4) in P. aeruginosa BSI. Urinary tract infection (UTI) was the most reported primary infection for E. coli (56,961/100,834), Klebsiella spp. (9,098/22,827) and P. aeruginosa (3,204/8,484) BSI. Insertion or manipulation of urinary catheters was reported for 26.4% (16,136/61,043) of E. coli, 41.6% (4,470 /10,734) of Klebsiella spp. and 49.0% (2,127/4,341) of P. aeruginosa BSI. The adjusted odds ratio (OR) of death among hospital-onset HA-BSI compared to CA-BSI was 2.0 (95% CI: 1.9-2.2) for E. coli, 2.1 (95% CI: 2.0-2.3) for Klebsiella spp. and 1.7 (95% CI: 1.5-2.0) for P. aeruginosa.ConclusionsAppropriate management of UTIs and urinary catheterisation is essential for reduction of these BSIs.

Dual encapsulation of curcumin and ciprofloxacin in chitosan nanoparticles attenuates Pseudomonas aeruginosa virulence, elastinolytic potential and quorum sensing genes

Pseudomonas aeruginosa is an important human pathogen that is responsible for various human infections and able to develop resistance to a variety of antibiotics. Drug encapsulation may provide sustained and more efficient drug delivery, particularly in case of the drugs with low bioavailability. This study aims to characterize the antivirulence and anti-quorum sensing (QS) properties of curcumin and ciprofloxacin dually encapsulated in chitosan NPs (Cur-Cip-CsNPs). The nanoparticles were synthesized and characterized by SEM, FT-IR, Zeta Potential, and DLS analyses. The antibacterial and antivirulence effects of the Cip-CsNPs, Cur-CsNPs, and Cur-Cip-CsNPs against P. aeruginosa strains were investigated by well diffusion, biofilm and pyocyanin quantification, swarming, swimming, twitching, and proteolytic and elastinolytic activity assays. The mRNA transcript levels of the lasIR and lasAB genes were also determined by real-time PCR. Cur-Cip-CsNPs were more potent antibacterial agents against P. aeruginosa compared with other NPs and inhibited bacterial planktonic growth at 160 mg/mL, reduced biofilm formation by 72.5-86.5 % and pyocyanin levels by 80.2-80.6 %, and significantly inhibited flagellar and fimbrial motility of P. aeruginosa. Furthermore, bacterial proteolysis and elastinolytic activity were reduced more efficiently by Cur-Cip-CsNPs compared with other nanoformulations. The expression of the lasI, lasR, lasA, and lasB was attenuated more efficiently by Cur-Cip-CsNPs compared with Cip-CsNPs and Cur-CsNPs. This study presents an innovative approach to overcome the challenges due to antibiotic resistance and provides a new therapeutic option against P. aeruginosa infections.

Identification and Initial Resuscitation of Critically Unwell Older Patients in the Emergency Department

Identifying and managing critically unwell older patients in emergency departments are challenging for all clinicians. Physiologic changes, multiple comorbidities, and medications often mask or confound serious conditions in older people, and vital signs can be misleading. Because standard triage methods may be inadequate for this population, enhanced triage systems that incorporate frailty assessments and tailored scoring systems are useful. Serial assessments tailored to the patient, biomarkers, and advanced imaging are also important to better detect and manage critical illness in older adults and improve outcomes. Here, the authors discuss diagnosis and management of critically ill older adults.

Pharmacodynamic interaction of apotransferrin and anti-pseudomonal antibiotics against extensively drug-resistant Pseudomonas aeruginosa in a dynamic PK/PD model

OBJECTIVES

The rise of antibiotic resistance in clinical settings poses a major challenge. Apotransferrin has emerged as a potential non-traditional therapy for combating infections, potentially preventing resistance development while enhancing bactericidal effects. This study evaluated the efficacy of apotransferrin combined with antipseudomonal antibiotics against extensively drug-resistant (XDR) Pseudomonas aeruginosa isolates.

METHODS

Twenty XDR P. aeruginosa clinical isolates were evaluated. Different apotransferrin concentrations were tested to determine the optimal in vitro concentration. Time-kill assays assessed the combined effects of apotransferrin with meropenem or ceftolozane/tazobactam (C/T). A chemostat model using four selected isolates validated the most effective combinations and monitored resistance emergence.

RESULTS

Apotransferrin monotherapy did not reduce bacterial load, but its combination with antipseudomonal antibiotics enhanced efficacy. Meropenem activity improved in 10/20 isolates, and C/T activity in 13/20 compared to antibiotic monotherapy. The chemostat model confirmed synergistic interactions between apotransferrin and C/T in two isolates, with additive effects in two others. This combination outperformed the most effective monotherapy in all isolates, with no emergence of new C/T-resistant strains.

CONCLUSIONS

In conclusion, the combination of apotransferrin with C/T demonstrated superior in vitro efficacy against XDR P. aeruginosa isolates compared to either treatment alone. These findings suggest that apotransferrin could be a valuable adjunctive therapy, enhancing the antimicrobial effects of existing antibiotics and potentially extending their clinical utility.

A Clinical Review of Prosthetic Joint Infections

Prosthetic arthroplasties are continuing to increase in the United States. While prosthetic joint infections are a less common adverse event, they can have a devastating impact on the patient as well as have a large economic burden on the health care industry. Prosthetic joint infections can be surgically managed by debridement, antibiotics, and implant retention, 1-stage revisions, 2-stage revisions, resection arthroplasties, arthrodesis, and amputations. Antimicrobial therapy typically includes 4 to 6 weeks of parenteral or highly bioavailable oral agents. Suppressive and chronic oral antimicrobial therapy may be pursued depending on the pathogen, clinical scenario, and retention of the prosthesis.

Pregnancy-related listeriosis in Spain

BACKGROUND

Pregnant women are at high risk of acquiring listeriosis, resulting in severe fetal and neonatal outcomes.

METHODS

All hospitalizations with a listeriosis diagnosis in pregnant women (obstetric listeriosis) and/or newborns (neonatal listeriosis) in Spain from 2000 to 2021 were examined using the National Registry of Hospital Discharges, employing ICD-9 and -10 coding lists.

RESULTS

A total of 540 and 450 hospital admissions for obstetric listeriosis and neonatal listeriosis were identified, respectively, with 146 adverse fetal-neonatal outcomes (miscarriage, fetal loss, stillbirth, and neonatal death). The incidence of obstetric listeriosis, neonatal listeriosis, and adverse fetal-neonatal outcomes (5.7, 4.7, and 1.5 per 100,000 deliveries, respectively) rose significantly from 2000 to 2021. No maternal deaths were recorded among women hospitalized with obstetric listeriosis. However, 9.8 % experienced miscarriage, related to bacteremia (OR=2.46), 6.3 % fetal loss and 5.9 % stillbirths, associated with chorioamnionitis (OR=3.42), which was identified in 77.7 % of 254 deliveries. Overall, 51.1 % of newborns developed sepsis, 58.9 % prematurity, 26.9 % ARDS, and 9.8 % died. ARDS (OR=2.76) and prematurity (OR=5.07) were associated with perinatal death in newborns with listeriosis. Pregnancy-related listeriosis was associated with increased risks of miscarriage (OR=1.75), intrauterine death (OR=17), preterm labor (OR=8.78), fetal distress (OR=2.10), cesarean section (OR=1.68), and stillbirth (OR=23.57).

CONCLUSIONS

Admissions for obstetric listeriosis and neonatal listeriosis in Spain have risen significantly from 2000 to 2021. Pregnancy-related listeriosis has a deleterious impact on fetal and neonatal outcomes, including miscarriages, fetal loss, stillbirth, and neonatal death. Surveillance, prevention, and prompt management of pregnant women with listeriosis and newborns with neonatal infection are warranted.

The Fate of the DAIR, Outcomes after 1 Year: A Large Database Study

Debridement with antibiotics and implant retention (DAIR) is commonly utilized for treatment of prosthetic joint infection (PJI) in total knee arthroplasty (TKA), particularly in cases of acute PJI. Reported success rates of DAIR have been highly variable, but the overall success rate of DAIR cohort studies is approximately 70 to 80%. However, no large database studies have investigated the success rate of DAIR. Therefore, we seek to provide a framework for large-database analysis of PJI interventions and their outcomes and to assess the success rate of DAIR. We queried the MarketScan Database for patients who underwent a DAIR (CPT 27310 and/or CPT 27486) procedure for indication of PJI (ICD-10 T84.53 OR T84.54) between January 1, 2017 and December 31, 2021. We identified reoperations (i.e., stage 1 revision, amputation, or arthrodesis) indicating failure of DAIR. Failure of DAIR treatment was defined by subsequent reoperation. We also identified prescriptions of suppression antibiotics more than 6 months after DAIR. We identified 1,018 patients who underwent a DAIR procedure for PJI. Of these patients, 195 (19.2%) underwent reoperation within 1 year and an additional 178 (17.5%) were prescribed suppressive antibiotics. For 780 patients with a minimum of 2 years of follow-up, 164 (21%) underwent reoperation and an additional 179 (22.9%) were prescribed suppressive antibiotics. Patients with obesity and patients younger than 60 years had significantly higher rates of having reoperation or suppressive antibiotics at 1 year following DAIR. DAIR is a viable option in the treatment of PJI, with an approximately 19% rate of reoperation at 2 years. Our findings are consistent with that of previously published literature.

Measuring the impact of hospitalization for infectious diseases on the quality of life of older patients in four European countries: the AEQUI longitudinal matched cohort study (2020-2023)

OBJECTIVES

To evaluate the impact of hospitalization for infectious diseases on the Health-Related Quality of life (HRQOL), multidimensional frailty, and functioning of older patients, we conducted a longitudinal matched cohort study in four European countries.

METHODS

HRQOL, frailty, and functioning were assessed using validated questionnaires at inclusion, at discharge, and up to 6 months later in patients aged over 65 years hospitalized for severe acute respiratory or bloodstream infections, and matched controls hospitalized for non-infectious conditions. Comparative analyses employed multilevel mixed-effect linear or logistic models to assess changes from inclusion.

RESULTS

Between 2020 and 2023, 1968 patients aged 65-100 years (mean, 81) were included; 1064 (54.1%) were male and 59 (3%) were institutionalized. Of these 1968 patients, 826 were hospitalized for infectious diseases and 1142 for non-infectious conditions. At inclusion, European Quality of Life 5 Dimensions and 3 Lines scores ranged from -0.7 to 1 (full HRQOL), with a median of 0.7 across all visits and groups. Compared with controls, patients hospitalized for infectious diseases had lower scores on the Activities of Daily Living (ADL) scale (median, 4.5 vs. 5.0; p 0.020) and the Instrumental ADL scale (median, 3.0vs. 4.0; p < 0.001). At discharge, Instrumental ADL scores were lower in patients hospitalized for infectious diseases than in controls (median, 4.0 vs. 5.0, p 0.003), indicating reduced functioning. The proportion of frail patients, determined by a Multidimensional Prognostic Index score between 0.67 and 1, was significantly higher among patients hospitalized for infectious diseases (n = 113/801, 14.1%) than controls (n = 108/1111, 9.7%; p 0.012). At six months, no statistically significant differences were observed between groups in changes from inclusion in HRQOL (European Quality of Life 5 Dimensions and 3 Lines, p 0.436), frailty (Multidimensional Prognostic Index, p 0.269), and functioning (ADL, p 0.993).

DISCUSSION

Hospitalization for infectious diseases and non-infectious diseases or conditions had a similar impact on HRQOL in non-institutionalized older adults.

Diagnostic Significance of Metagenomic Next-Generation Sequencing in Immunocompromised Patients With Suspected Pulmonary Infection

Immunocompromised hosts are highly vulnerable to lung infections, but the efficacy of traditional diagnosis is unsatisfactory. Metagenomic next-generation sequencing (mNGS) has high throughput and broad coverage. Its value in different types of immunocompromised patients has yet to be fully explored. Therefore, the study aims to evaluate the value of mNGS in immunocompromised patients. Clinical data from immunocompromised patients with suspected pulmonary infection (PI) (September 2018-2021) were retrospectively analysed. Patients were categorised into PI (87 cases) and non-pulmonary infection (NPI, 14 cases) groups. The diagnostic performance between mNGS and conventional microbiological tests (CMTs) was compared. Subgroup analyses were also conducted based on whether the patients received organ transplantation, including the comparison of the diagnostic performance of mNGS and culture and the spectrum of characteristics among them. mNGS demonstrated significantly elevated diagnostic sensitivity (p < 0.001) over traditional methods, with a pronounced advantage in identifying mixed PIs (p < 0.05). Among immunocompromised cohorts, mNGS outperformed cultures, showing higher positivity rates in both organ transplant (p < 0.001) and non-transplant patients (p < 0.001). Mixed infections, predominantly bacterial-fungal, were more prevalent in transplant recipients with reduced lymphocytes and CD4+ T cells. Pathogen profiles differed, with Pneumocystis jirovecii, Cytomegalovirus, and Pseudomonas aeruginosa predominating in organ transplant recipients, and P. jirovecii, P. aeruginosa , Streptococcus pneumoniae and Streptococcus pallidum in non-transplant individuals. mNGS is valuable in diagnosing PI and mixed infections in immunocompromised patients, which may be particularly suitable for identifying mixed infections in patients with organ transplants and low lymphocyte and CD4+ T lymphocyte counts.

Comprehensive surveillance of antimicrobial susceptibility across adult and pediatric populations in Catalonia: Insights from community, hospital, and long-term care facility settings

BACKGROUND

This study presents comprehensive data on antimicrobial susceptibility across healthcare settings and age groups in Catalonia, Spain.

METHODS

Susceptibility data were collected from 37 microbiology laboratories between 2020 and 2022 for community-acquired infections (CAIs), and 2021 and 2022 for hospital and long-term care facilities (LTCFs). Susceptibility was calculated based on the proportion of susceptible strains among the total strains.

RESULTS

Pediatrics: Community-acquired infections (CAIs): in urinary tract infections (UTIs), extended-spectrum beta-lactamase production (ESBL-P) Escherichia coli was 3.8%. Streptococcus pneumoniae was highly susceptible to penicillins (97.5%). Community-acquired methicillin-resistant Staphylococcus aureus was 6.8%. Hospital-acquired infections (HAIs): ESBL-P in E. coli and Klebsiella pneumoniae were 6.7% and 9.4%. Carbapenem resistance in Enterobacter cloacae complex was less than 1%. Extremely drug-resistant Pseudomonas aeruginosa was 1.6%.

ADULTS

CAIs: In UTIs, E. coli showed high susceptibility to fosfomycin (>95%) and 9% of ESBL-P. In respiratory tract infections, Streptococcus pyogenes exhibited reduced susceptibility to macrolides (67%) and clindamycin (75.1%), while Haemophilus influenzae and S. pneumoniae remained susceptible to penicillins (78% and 96%). HAIs: E. coli showed 12.8% of ESBL-P and K. pneumoniae 20%. Carbapenem resistance was mainly identified in E. cloacae (2.8%) and K. pneumoniae (2.2%). P. aeruginosa showed high susceptibility to meropenem (87%). Methicillin-resistance was detected in 22% of S. aureus. Long-term care facilities (LTCFs): E. coli causing UTI was highly susceptible to carbapenems (99%), nitrofurantoin (96%), and fosfomycin (93%) with 25.8% of ESBL-P. K. pneumoniae showed 40% ESBL-P and 2.9% of carbapenem resistance. P. aeruginosa exhibited decreased susceptibility to quinolones (69.5%) and highly susceptibility to meropenem (88.5%).

CONCLUSION

The data underscore the necessity of stratified susceptibility reports by setting, type of infection, and age.

Revision for humeral stem loosening: a systematic review

INTRODUCTION

Humeral loosening (HL) is an uncommon indication for revision shoulder arthroplasty. This systematic review describes patient characteristics (prosthetic type removed, reimplanted, and septic vs. aseptic loosening status), re-revision rate, and outcomes following revision surgery for a loose humeral stem.

MATERIALS AND METHODS

An electronic database search of PubMed, Scopus, Embase, and Cochrane was conducted accordant to the Preferred Reporting Items for Systematic Reviews and Meta-analyses method. Studies that reported information on patients who had revision arthroplasty due to HL and reported their postrevision outcomes were included in this review.

RESULTS

Our review included 13 studies, from which 119 revision cases due to HL were extracted. The prostheses subtypes revised for HL were 48.7% (58/119) anatomic total shoulder arthroplasties (TSAs), 46.2% (55/119) reverse shoulder arthroplasties (RSAs), and 5.0% (6/119) hemiarthroplasties (HAs). The implants used to revise patients with HL were 52.2% (59/113) RSAs, 35.4% (40/113) HAs, and 12.4% (14/113) TSAs. Septic loosening occurred in 11.7% (14/119) of the cases. Ninety-seven cases provided details regarding subsequent revisions, of which 28.9% (28/97) were re-revised. The following outcome scores were available: mean satisfaction rate was 71.4% (n = 49), the mean total American Shoulder and Elbow Surgeons score was 52.5 (range 30-66) (n = 28), and the mean Constant score was 40.3 (range 34-41.3) (n = 14).

CONCLUSION

The most revised implants for HL were TSAs and RSAs. Reverse shoulder arthroplasties were the most common implants used for revision, followed by HAs. Aseptic loosening accounted for most cases, suggesting that infection is rarely the primary cause of HL. There is a pronounced risk of re-revision for recurrent HL. The irregular reporting of validated outcome scores makes it difficult to draw definitive conclusions regarding the treatments of these patients.

Strategies for periprosthetic joint infection management in resource-limited settings: the applicability of EBJIS criteria

BACKGROUND AND PURPOSE

Periprosthetic joint infection (PJI) is a significant and challenging healthcare issues. Accurate diagnosis is essential for effective treatment. The aim of our study is to underscore the usefulness of the new EBJIS definition and criteria when applied in a developing country department.

METHODS

We conducted a retrospective analysis of a single-center cohort of consecutive revision arthroplasties (January 2018-June 2024). This study was carried out at the Department of Orthopedics and Trauma Surgery in the University Hospital Fattouma Bourguiba in Monastir, Tunisia. Were included in our research patients who underwent revision surgery for arthroplasties due to septic failure. Exclusion criteria were: surgery performed within the previous six weeks, antibiotic-loaded bone cement spacer in place, the second step of a two-stage revision and periprosthetic fractures.

RESULTS

A total of 46 patients were included in the study. According to the EBJIS criteria, our cohort was divided into two groups: "likely infection" including 12 patients (26.1%) and "confirmed infection" with 34 patients (73.9%). Clinical signs like inflammation (Se 85.3%, PPV 76.32%) and pain (Se 76.47%, PPV 70.27%) demonstrate higher sensitivity but low specificity. Among paraclinical tests, a CRP level > 10 mg/dL is highly sensitive (97.06%), while PMN > 80% shows perfect specificity (100%). Tissue samples with more than two positives and cultures with the same microorganism exhibit high sensitivity (96.66% and 80%) and PPV (84.85% and 85.71%).

CONCLUSION

Establishing PJI diagnosis is challenging and depends on paraclinical testing. We highlight the lack of important diagnostic instruments in settings with limited resources.

Efficacy and Safety of Aerosol Inhalation of Colistin Sulfate for the Treatment of Carbapenem-Resistant Klebsiella pneumoniae Infection in the Peri-Operative Period of Liver Transplantation: A Single-Center Retrospective Study

Objective: This study intended to evaluate the clinical efficacy and safety of colistin sulfate aerosol inhalation in combination with ceftazidime-avibactam for the treatment of pulmonary carbapenem-resistant Klebsiella pneumoniae (CRKP) infection during the peri-operative period of liver transplantation. Materials and Methods: A retrospective analysis was designed to investigate 52 patients who developed pulmonary CRKP infection after liver transplantation between December 1, 2019, and November 30, 2022. On the basis of whether they received colistin sulfate aerosol inhalation, the patients were divided into the treatment group (n = 29) and the control group (n = 23). The baseline information, infection status, CRKP enzyme type, inflammatory markers, liver and kidney function, and prognosis were compared and analyzed. Results: There were no significant differences in patient characteristics, infection status, and drug resistance enzyme type between the treatment group (treated with colistin sulfate aerosol inhalation and ceftazidime and avibactam sodium for injection) and the control group (treated with ceftazidime and avibactam sodium for injection alone). Colistin sulfate aerosol inhalation treatment reduced concentrations of inflammatory markers, with post-treatment white blood cell count, procalcitonin, and C-reactive protein significantly lower than pre-treatment levels (p < 0.05). Except for C-reactive protein at 14 days (p = 0.032), the two groups had no significant differences in other indicators. There were no significant differences in alanine aminotransferase, aspartate aminotransferase, total bilirubin, and glomerular filtration rate after treatment, indicating no discernible alteration in liver and kidney function. In addition, the treatment group took a significantly shorter time to normalize body temperature compared with the control group (p = 0.025), but there were no significant differences in the cure with no colonization rate and all-cause mortality rate between the two groups. Conclusions: The combination of colistin sulfate aerosol inhalation and ceftazidime and avibactam sodium for injection is effective in treating pulmonary CRKP infection during the peri-operative period of liver transplantation. It does not impose an additional burden on liver and kidney function, providing a new treatment option for this type of infection.

Antibiotic conjugates: Using molecular Trojan Horses to overcome drug resistance

Antimicrobial resistance (AMR) has become a global health crisis due to the rapid emergence of multi-drug-resistant bacteria. The paucity of novel antibiotics in the clinical pipeline has exacerbated this issue, thereby warranting the development of new antibacterial therapies. The 'Trojan Horse' strategy entails conjugating antibiotics with bioactive components that not only facilitate the entry of antibiotic molecules into bacterial cells by circumventing the membrane barriers, but also augment the effects of conventional antibiotics against recalcitrant pathogens. These Trojan Horse elements can also serve as a promising tool for repurposing drugs with hitherto unexamined antimicrobial activity, or drugs with limited clinical utility due to considerable toxic side effects. In this review, we have discussed the current state of research on antibiotic conjugates with monoclonal antibodies (mAbs), antimicrobial peptides (AMPs) and the iron-chelating siderophores. The rationale and mechanisms of different antibiotic conjugates have been summarized, and the preclinical and clinical evidence pertaining to the activity of these conjugates against drug-resistant pathogens have been reviewed. Furthermore, the challenges associated with the clinical translation of these novel antimicrobials, and the future research directions have also been discussed. While antibiotic conjugates offer an attractive alternative to conventional antimicrobials, there are several obstacles to their clinical translation. A greater understanding of the mechanisms underlying AMR, and continuing advances in genetic engineering, synthetic biology, and bioinformatics will be crucial in designing more selective, potent, and safe antibiotic conjugates for tackling multi-drug resistant (MDR) infections.

The use of Ceftobiprole in treatment pathways in Spain: an expert panel review

BACKGROUND

Ceftobiprole is a fifth-generation β-lactam approved in Spain solely for the treatment of community- and hospital-acquired pneumonia.

OBJECTIVES

To discuss the use of ceftobiprole in the Spanish healthcare setting, and to review and define its positioning for treatment of infections, both in hospital and outpatient settings.

METHODS

In November 2023, an in-person meeting was held, with ten healthcare professionals with expertise in infectious diseases and/or hospital-at-home settings in attendance.

RESULTS

The experts discussed the use of ceftobiprole in treating CAP and HAP, and in off-label indications where data exist to support this. In clinical trials and real-world studies, ceftobiprole has shown comparable efficacy and safety to other clinically approved antimicrobials for the treatment of skin and soft tissue, bone and joint, bacteraemia and endocarditis infections. The panel considered the use of ceftobiprole in hospital at home/outpatient parenteral antimicrobial therapy settings for all indications discussed.

CONCLUSIONS

Experts concluded that ceftobiprole may be a suitable alternative therapy in complex infections caused by Gram-positive and select Gram-negative bacteria. They agreed that use in CAP and HAP could be expanded and that there was potential for use in all unlicensed indications discussed. The panel noted the benefits of its broad spectrum in polymicrobial infections, whilst the ability to administer the drug by continuous perfusion could enable its use in outpatient settings. Further research could highlight its suitability across additional conditions and populations.

Sex differences in bacterial meningitis and associations with socioeconomic indicators: a systematic review and meta-analysis with metaregression

INTRODUCTION

We aimed to describe global sex-specific proportions and case fatality ratios of bacterial meningitis and to explore their associations with the Human Development Index (HDI) and Gender Inequality Index (GII).

METHODS

Google Scholar and MEDLINE (via PubMed.gov) were searched in January 2022 using the terms "bacterial meningitis" and "mortality". Studies with a mean observation period after the year 1940 and reporting ≥10 patients with community-acquired bacterial meningitis and their survival status were included, irrespective of the participants' age. Studies that selected participants by specific risk factors, reported specific pathogens only, or had >10% missing outcomes were disregarded. Data were extracted by one researcher and validated by a second researcher. The main outcomes, sex-specific proportions and case fatality ratios, were analysed using random-effects models. Associations with HDI and GII were explored using metaregression.

RESULTS

In this meta-analysis with metaregression, from 371 studies with 157 656 meningitis episodes, 217 (58%) reported the patients' sex and 41 (11%) reported sex-specific outcomes. Proportion of males was 58% (95% CI 57%-59%, prediction interval (PI) 45%-71%). Case fatality ratios were slightly higher in females (male-to-female fatality ratio, 0.89, 95% CI 0.78 to 1.01, PI 0.53-1.49). The size of the male proportion was strongly associated with HDI (per index point, -0.64, 95% CI -0.88 to -0.40; R2 16%; p<0.001) and GII (per index point, 0.61, 95% CI 0.39 to 0.83; R2 19%; p<0.001). Sex-specific case fatality ratios were weakly associated with HDI (per index point, 0.53, 95% CI -0.19 to 1.25; R2 2%; p=0.15) and GII (per index point, -0.58, 95% CI -1.55 to 0.39; R2 7%; p=0.24).

CONCLUSION

Based on worldwide reporting from the last 80 years, we show that indicators of human development and gender inequality are associated with sex-based disparities and case fatality ratios in bacterial meningitis.

Amphiphilic mPEG-PLGA copolymer nanoparticles co-delivering colistin and niclosamide to treat colistin-resistant Gram-negative bacteria infections

Colistin is the last line of defense against multidrug-resistant (MDR) Gram-negative bacterial infections, yet it is restricted due to high drug resistance and toxicity. The combination therapy of colistin and niclosamide exhibits excellent synergistic antibacterial activity against Gram-negative bacteria. How to co-deliver these two drugs with vastly different pharmacokinetic properties in sufficient amounts to the infection site is the core issue that must be resolved for the clinical translation of this drug combination. Here, we designed and prepared a nanosystem capable of co-loading colistin and niclosamide with different physicochemical properties into mPEG-PLGA nanoparticles (COL/NIC-mPEG-PLGA-NPs) to overcome the resistance of multiple colistin-resistant bacteria to colistin and alleviate its toxicity. Mechanistic studies revealed that the COL/NIC-mPEG-PLGA-NPs enhanced the affinity of delivered COL to the modified membrane of colistin-resistant bacteria. The increased membrane permeability caused by colistin promotes an influx of niclosamide, which reduces efflux pump activity and generates intracellular ROS stress, eliminating colistin-resistant bacteria. In addition, the nanoparticles proved non-toxic both in vitro and in vivo. Overall, our study has profound insights into the use of nanosystems with high biosafety for the treatment of infections caused by colistin-resistant bacteria.

Accelerating antimicrobial stewardship: An AI-CDSS approach to combating multidrug-resistant pathogens in the era of increasing resistance

OBJECTIVES

The World Health Organization has identified Klebsiella pneumoniae (KP) and Pseudomonas aeruginosa (PA) as significant public health threats owing to high antibiotic resistance. Traditional antibiotic susceptibility testing (AST) methods, crucial for determining the most suitable treatment regimen, typically require approximately 48-96 h (2-4 days) to yield results, including bacterial culture, rapid identification via matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), and subsequent AST, which is too long for urgent clinical decisions. Here, we developed an artificial intelligence-clinical decision support system (AI-CDSS) utilizing machine learning to analyze MALDI-TOF MS data for antibiotic resistance prediction for these pathogens.

METHODS

From 165,299 bacterial specimens, we selected 12,967 KP and 9,429 PA cases. Predictive models, the core of the AI-CDSS, were built using advanced machine learning algorithms, such as the random forest classifier (RFC) and light gradient boosting machine (LGBM), with GridSearchCV and 5-fold cross-validation optimization and robustness.

RESULTS

Both the RFC and LGBM models demonstrated strong predictive performance, with area under the curve values predominantly ranging from 0.91 to 0.95. Sensitivity, specificity, positive predictive value, and negative predictive value primarily exceeded 80 %, ensuring reliable detection of resistance patterns. The AI-CDSS was designed to provide real-time, clinically actionable recommendations, enabling targeted antibiotic selection up to one day faster than conventional AST.

CONCLUSIONS

Integrating MALDI-TOF MS with machine learning in AI-CDSS significantly enhanced clinical decision-making, representing a major advancement in the rapid management of infectious diseases and antimicrobial stewardship.

Shoulder Arthroplasty: Current Evidence and Techniques on Infection Prevention

The incidence and indications for shoulder arthroplasty are expanding. Although the procedure is generally successful, complications can occur. One of the most devastating is prosthetic joint infection of the shoulder. Efforts to prevent prosthetic joint infection of the shoulder vary from mechanical to pharmacologic. We review evidence-based prevention efforts ranging from preoperative optimization to pharmaceutical prophylaxis to draping techniques. Our paired review on diagnosis and treatment is also referenced.

Antimicrobial Suppressive Therapy in Prosthetic Valve Endocarditis Rejected from Surgery despite Indication

BACKGROUND

Prosthetic valve endocarditis (PVE) incidence is rising in older patients, often rejected for surgery, leading them to a poor prognosis. Optimal antibiotic management is unknown for these patients. We compared the efficacy and safety of suppressive (SAT) versus conventional antimicrobial therapy (CAT) in this setting.

METHODS

We conducted a prospective, multicentric, cohort study in southwest France including patients with PVE rejected from surgery despite indication, and surviving the initial 6 weeks of intravenous therapy. Beyond this period, patients could or not receive SAT, according to endocarditis team decision. Primary outcome was a composite endpoint of one-year all-cause mortality and PVE-related hospitalization. Secondary outcome was the incidence and nature of SAT-related adverse events.

RESULTS

Between 2012 and 2022, 88 patients were included in the study, 42 receiving SAT and 46 CAT. Mean age was 69.4 ±16.4 years and patients were highly comorbid (mean Charlson Comorbidity Index 5.6 ± 2.7). Main organisms included Streptococcus spp. (26/88, 29.5%) and Staphylococcus aureus (25/88, 28.4%). The primary composite outcome occurred in 7/42 (16.7%) patients in the SAT group, and 16/46 (34.8%) in the CAT group. Using a Cox model, SAT was significantly and independently associated with a lower incidence of one-year primary outcome (Hazard ratio 0.23, 95% CI 0.08 - 0.67, p=0.007). Adverse effects in the SAT group were reported for 6/42 patients (14.3%). These effects were limited, causing only one treatment discontinuation.

CONCLUSION

In patients with PVE rejected from surgery despite indication, SAT may be safe and associated with better outcomes than CAT.

Periprosthetic Joint Infection Mortality After Total Hip Arthroplasty is Comparable to 5-Year Rates of Common Cancers: A Meta-Analysis

BACKGROUND

Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is a rare, but devastating complication with elevated morbidity and mortality. While associated with increased mortality, the reported range is broad and most often reported after 2-stage exchange arthroplasty. This study aimed to report the overall mortality after PJI following primary THA, PJI mortality at one, three, and 12 months, and mortality after common PJI treatments. We hypothesized that mortality after THA PJI would be high, increase over time, and be highest after a 2-stage exchange.

METHODS

A meta-analysis of articles from six databases, queried from inception to December 2023, was performed. Full-length articles reporting mortality following PJI after primary THA were included. Articles with oncologic, infectious, or traumatic THA indications were excluded. Articles investigating high-risk patient populations, including those who had solid organ transplants, active cancer diagnoses, and synchronous PJI, were excluded. There were two independent reviewers who reviewed articles. Mortality over time and after treatment (debridement, antibiotics, and implant retention [DAIR], 1- and 2-stage exchange arthroplasty) was collected. A meta-analysis of proportions with inverse-variance proportion models was constructed for overall mortality.

RESULTS

A total of 19,917 patients who had PJI after THA from 20 studies were included. Overall mortality was 11.0% (95% CI [confidence interval]: 5 to 18.8) at a mean follow-up of 40.3 months (range, one to 240). Pooled mortality at one, three, and 12 months was 1.1, 3.7, and 10.0%, respectively. Mortality following treatment with DAIR, 1-stage, and 2-stage exchange was 7.8% (95% CI: 2.3 to 15.9), 1.6% (95% CI: 0 to 14), and 9.2% (95% CI: 5.4 to 13.9), respectively. Considerable heterogeneity was present.

CONCLUSIONS

Mortality after THA PJI is high (11.0%) within three years of arthroplasty and comparable to 5-year rates of cancers such as breast (11%) and prostate (1%) cancers. A multidisciplinary approach, like those adopted in the treatment of cancer, is warranted to reduce the burden of this devastating complication.

Assessment of in vitro antimicrobial activities of ceftolozane/tazobactam and ceftazidime/avibactam against carbapenem-resistant Pseudomonas aeruginosa clinical isolates

BACKGROUND

Carbapenem resistant Pseudomonas aeruginosa (P. aeruginosa) is a global health concern that poses a challenge to treat in health care facilities. Ceftazidim/avibactam and ceftolozane/tazobactam have a potential role in treatment of multi-drug resistant phenotypes including carbapenem resistant P. aeruginosa. Therefore, we aimed to assess the in vitro antimicrobial activity of ceftazidime/avibactam and ceftolozane/tazobactam against carbapenem-resistant P. aeruginosa (CRPA) strains with different β-lactamase/carbapenemase genes.

METHODS

Sixty CRPA isolates identified from clinical samples were examined for antimicrobial susceptibility including ceftazidim/avibactam and ceftolozane/tazobactam by Vitek2 compact system, and carbapenemase production by modified carbapenem inactivation method (mCIM) test and carbapenemase producing genes by polymerase chain reaction (PCR).

RESULTS

Isolates were resistant to imipenem in 96.7% and meropenem in 88.3%. of isolates. Carbapenemase production by mCIM test was 70% compared to 73.3% by (PCR). Carbapenemase encoding genes blaNDM, blaVIM and blaOXA-48 were detected in 60%, 41.7% and 25% respectively while blaIMP and blaKPC weren't identified in this study. Among CRPA, both ceftazidim/avibactam and ceftolozane/tazobactam; were sensitive in only 11.7% of the isolates. Resistance to ceftazidim/avibactam and ceftolozane/tazobactam in isolates owning blaNDM, blaVIM, blaOXA-48 and those having combined blaNDM, blaVIM and blaOXA-48 carbapenemase resistance genes were 97.2%, 92%, 100% and 100% respectively.

CONCLUSION

Modified carbapenem inactivation method test gave satisfactory results and could be used as an alternative to expensive genotypic methods. Ceftazidim/avibactam and ceftolozane/tazobactam were unsuccessful against carbapenem resistant P. aeruginosa isolates carrying carbapenemase genes especially metallo-β lactamase genes. Therefore, it is essential to detect susceptibility patterns to newly introduced β-Lactam/β-Lactamase inhibitor combinations due to the emerging resistance to these therapeutics.

Management of Gram-positive multiresistant bacteria prosthetic joint infection: a narrative review on current and innovative strategies

BACKGROUND

Prosthetic joint infection (PJI) is a devastating complication of arthroplasty surgery, mostly caused by Gram-positive pathogens, including S. aureus and coagulase-negative staphylococci (CNS). Multidrug resistance is of major concern in this setting: i) it can negatively impact outcome, restricting the use of the most effective antimicrobials; ii) it may influence the choice of surgical strategies; and iii) it restrains the therapeutic options to newly labelled antimicrobials with limited experience in PJI.

OBJECTIVES

To provide a comprehensive overview of the clinical impact of antimicrobial resistance in Gram-positive PJI and on current and innovative therapeutic strategies.

SOURCES

The review is based on PubMed searches for relevant topics, including multiresistant staphylococci PJI and the discussed specific therapeutic approaches. Given the very few randomized trials in this setting, discussion is mostly based on observational studies and the experience and opinion of the authors.

CONTENT

Methicillin resistance is an important concern in staphylococcal PJI, especially in CNS. However, its impact on outcome is controversial. Conversely, rifampicin and/or fluoroquinolone resistance are associated with worse prognosis, and might be considered when defining difficult-to-treat pathogens in the PJI setting. There is very little experience with recently developed anti-Gram-positive antimicrobial in PJI, but evaluations of their antibiofilm activities are promising, and some of them might represent significant advances regarding antimicrobial tolerance (such as tedizolid) or PK profiles (such as dalbavancin) during long-term treatment required for PJI. Evaluation of innovative strategies in this setting is crucial, including repositioning of current surgical options using local antimicrobial delivery, PK monitoring and modelling to optimize antimicrobial therapy, suppressive antimicrobial treatment and/or phage-based approaches.

IMPLICATIONS

Prosthetic joint infections caused by resistant Gram-positive bacteria - including rifampicin- and/or fluoroquinolone-resistant staphylococci - may be associated with a poorer prognosis. It is therefore essential to optimise medical and surgical management, and to find new therapeutic alternatives.

Conditional lethality and suppressor analysis of plasmid-based temperature-sensitive fabZ expression in Pseudomonas aeruginosa

FabZ, a β-hydroxyacyl-ACP dehydratase in the Type II fatty acid synthesis pathway, is essential for the viability of Pseudomonas aeruginosa by ensuring proper fatty acid elongation and membrane stability. However, the precise genetic interactions between fabZ and lipid A biosynthesis genes, such as lpxA and lpxC, as well as the potential existence of other suppressor genes of fabZ in P. aeruginosa, remain unclear. To explore these genetic interactions and identify potential suppressor genes, we constructed a conditional fabZ mutant, ΔfabZ(p_ts-fabZ), by deleting the chromosomal fabZ gene and complementing it with a temperature-sensitive plasmid-borne copy. The ΔfabZ(p_ts-fabZ) mutant exhibited lethality and cell morphology defects at a restrictive temperature, confirming its essentiality. Genetic interaction analyses revealed that deletion of lpxA or lpxC failed to rescue ΔfabZ(p_ts-fabZ) lethality at restrictive temperature. Through suppressor screening, we isolated a mutant strain capable of rescuing ΔfabZ lethality and identified lpxH as the suppressor gene using genome resequencing. Further analysis revealed that the fabZ and lpxH double mutant (ΔfabZΔlpxH) produced odd-chain fatty acids, identified as pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) through fatty acid methyl ester (FAME) analysis coupled with gas chromatography-mass spectrometry (GC-MS), and supplementation with these fatty acids restored the growth and morphology of ΔfabZ(p_ts-fabZ) and ΔlpxH(p_ts-lpxH) mutants at restrictive temperature, suggesting their critical role in membrane stability. These results indicate that deletion of lpxH serves as a genetic suppressor of ΔfabZ lethality, highlighting a previously unrecognized compensatory mechanism involving odd-chain fatty acid synthesis essential for membrane stability in P. aeruginosa.

A Systematic Literature Review of the Epidemiology of Complicated Urinary Tract Infection

INTRODUCTION

Urinary tract infections (UTIs) are common bacterial infections and present with heterogeneous clinical phenotypes. Whereas many uncomplicated UTIs resolve spontaneously or with antibiotic treatment, a complicated UTI (cUTI) presents with greater morbidity and a higher risk of treatment failures. The goal of this study was to estimate the real-world epidemiology of cUTI, including acute pyelonephritis (AP) and catheter-associated UTIs (CAUTIs), and its associated mortality internationally.

METHODS

A systematic literature search was conducted using PubMed, Embase, Cochrane, and EconLit databases for relevant articles published between July 2013 and July 2023 covering Europe and the following countries: France, Italy, Germany, Spain, the UK, China, Japan, and the US (US). Search terms relating to cUTI, AP, CAUTI, outcomes of interest (epidemiology), and real-world research designs were used. There were no language limitations (protocol registry: PROSPERO-CRD42023454794).

RESULTS

Database searches yielded 1014 unique records, of which 91 met the prespecified inclusion criteria; bibliography and conference abstract searches yielded 27 additional records for a total of 118 records for inclusion. Disease presentation and reported outcomes varied widely across studies, and most studies reporting incidence and prevalence of cUTI were from the US (21 of 29). No studies reporting incidence or prevalence rates of cUTI in China, Germany, or the UK were identified. Overall, high antibiotic resistance rates were reported in both inpatient and outpatient settings. The inpatient cohort mortality rates were highly variable (0-50%) depending on the patient population.

CONCLUSIONS

While disease presentation and reported outcomes varied widely across studies, cUTIs represent a considerable burden in terms of incidence, prevalence, drug resistance, and mortality, yet vast knowledge gaps remain in the literature. There is a crucial need to address these gaps to effectively evaluate new treatments and improve future analyses of cUTI burden and outcomes.

Application of [99mTc]Tc-GSA in the diagnosis of Staphylococcus aureus infections

INTRODUCTION

Staphylococcus aureus can cause a variety of conditions such as bacteremia, sepsis, toxic shock syndrome, pneumonia, and infective endocarditis; therefore, a rapid and accurate diagnosis should be made to pinpoint the site of infection. This study aimed to use the existing nuclear medicine tracer [99mTc]Tc-dimercaptosuccinic acid galactosyl human serum albumin ([99mTc]Tc-GSA) as a simple technique for the early diagnosis of S. aureus infection.

METHODS

The in vitro studies evaluated the accumulation of [99mTc]Tc-GSA in S. aureus. In addition, the effect of metabolic and vital activity and inhibition of asialoglycoprotein receptors on [99mTc]Tc-GSA accumulation were evaluated. In vivo studies were performed on the biodistribution and imaging of [99mTc]Tc-GSA in the S. aureus SR3637 mouse thigh infection model.

RESULTS

In vitro studies have confirmed that [99mTc]Tc-GSA accumulates to the same extent as 2-deoxy-2-[18F]fluoro-d-glucose, and it was thought that [99mTc]Tc-GSA binds to the receptors that recognize the saccharide molecules and glycan chains expressed in S. aureus. In addition, in the distribution and imaging of [99mTc]Tc-GSA, it was confirmed that the latter accumulates at the infection site and shows a clear contrast with the non-infected site.

CONCLUSION

The application of [99mTc]Tc-GSA to the imaging diagnosis of S. aureus infection is expected to non-invasively detect the localization of S. aureus in real time, pinpoint the site of infection and determine the number of viable bacteria, and help in the selection of optimal therapeutic agents and treatments.

Outcomes of infective endocarditis in patients with end-stage renal disease in Spain: a population-based study

BACKGROUND

Patients with end-stage renal disease (ESRD) have a higher risk of infective endocarditis (IE) and a worse prognosis associated with it. Our aim is to analyze the clinical characteristics and outcomes of patients with IE and ESRD in Spain, while exploring potential differences between patients undergoing dialysis and other patients with ESRD.

METHODS

Retrospective observational population-based study analyzing 9,008 episodes of IE recorded between 2016 and 2019, using data from the Spanish Minimum Basic DataSet. Among these, 428 patients had ESRD, including 332 who were undergoing dialysis. A multivariable and multilevel logistic regression model was constructed to assess the association between various factors and in-hospital mortality in ESRD patients.

RESULTS

Compared to patients without ESRD, those with ESRD were younger, had more comorbidities, and showed a higher prevalence of infections caused by Staphylococcus aureus (31.8% vs. 18.4%; p < 0.001) and coagulase-negative staphylococci (19.2% vs. 14%; p = 0.006). ESRD patients also experienced septic shock more frequently as an in-hospital complication (12.1% vs. 8.9%; p = 0.007). Additionally, they underwent cardiac surgery less often (12.6% vs. 19.6%; p < 0.001) and had significantly higher in-hospital mortality rates (33.4% vs. 26.9%; p = 0.003) than patients without ESRD. Among ESRD patients, those undergoing dialysis had more comorbidities and a higher proportion of S. aureus infections (36.1% vs. 16.7%; p < 0.001). The multilevel analysis revealed that neither dialysis nor cardiac surgery were independently associated with in-hospital mortality.

CONCLUSIONS

Patients with ESRD and IE exhibit distinct clinical and microbiological characteristics compared to other IE patients. Additionally, they are less likely to undergo cardiac surgery and experience significantly higher in-hospital mortality rates. In ESRD patients with IE, neither dialysis treatment nor cardiac surgery were identified as independent risk factors for mortality.

Outcomes after suppressive antimicrobial therapy for prosthetic joint infection: a prospective cohort study

The objective of this study was to describe the use of and outcomes after suppressive antimicrobial therapy (SAT) in a large prospective peri-prosthetic joint infection (PJI) cohort. SAT was defined as antimicrobial therapy continuing beyond 12 months from PJI diagnosis or where there was an early intention for SAT. The primary outcome was "treatment failure" at 24 months, defined as any of (i) clinical evidence of (ii) further surgery for or (iii) death from PJI. Secondary outcomes included quality of life (QOL) scores using Short Form 12 (SF-12) and Oxford hip (OHS) and knee (OKS) scores. SAT was prescribed for 223 of 720 (31.0%) in the cohort. Patients prescribed SAT were more likely to be older, have comorbidities, chronic PJI, higher C-reactive protein, sinus tract, or be treated with debridement and implant retention. The most frequently prescribed antimicrobials for SAT were ciprofloxacin (64 [21%]), amoxicillin (42 [14%]), and rifampicin (35 [12%]). Treatment failure was more common in the SAT group (75/185 [40.1%] vs 85/447 [19.0%]). After propensity score-adjusted analysis, SAT remained associated with higher rates of treatment failure (aOR 2.48, 95% CI [1.66-3.72]). Although 24-month QOL scores were lower in the SAT group, there were similar improvements from baseline in functional joint scores in SAT and non-SAT groups (OHS median interquartile range [IQR] +8.5 [19.0] vs +7.0 [22.0]; P = 0.78 and OKS +8.0 [20.0] vs +7.0 [22.0]; P = 0.53). SAT use for PJI is common, and in this study, it was not associated with improved outcomes. Identifying patients most likely to benefit from SAT should be explored in carefully designed controlled trials.